Abstract:
Methods and apparatuses for in-situ cleaning of semiconductor electroplating electrodes to remove plating metal without requiring !the manual removal of the electrodes from the semiconductor plating equipment. The electrode is placed into the plating liquid and, an electrical current having reverse polarity is passed between the electrode and plating liquid. Plating deposits which have accumulated on the electrode are electrochemically dissolved and removed from the electrode.

Description:
TECHNICAL FIELD 
     The technical field of this invention is methods for cleaning and maintaining electrodes used in electroplating apparatus used in the electroplating of metals onto semiconductor workpieces. 
     BACKGROUND OF THE INVENTION 
     In the production of semiconductor wafers and other semiconductor articles it is necessary to plate metals onto the semiconductor surface to provide conductive areas which transfer electrical current. There are two primary types of plating layers formed on the wafer or other semiconductor workpiece. One is a blanket layer used to provide a metallic layer which covers large areas of the wafer. The other is a patterned layer which is discontinuous and provides various localized areas that form electrically conductive paths within the layer and to adjacent layers of the wafer or other device being formed. 
     The plating of copper onto semiconductor articles has in particular proven to be a great technical challenge and at this time has not achieved commercial reality due to practical problems of forming copper layers on semiconductor devices in a reliable and cost efficient manner. 
     In the electroplating of copper, aluminum, tin, nickel, and other metals there is a reoccurring problem of buildup of the metal being plated on the electrodes. In typical processes the anode is present in the plating bath and the cathode is connected to the wafer or other semiconductor article being plated. Deposits of the plating metal occur not only on the wafer but also at the cathodes. When these deposits of plating metal become substantial, then they must be removed. Removal is needed to prevent unintended attachment of the electrodes to the wafer being plated, and to prevent small particles of plating metal from breaking free and lodging on the wafer in a local which results in a defect. 
     Under prior knowledge it has been it has been necessary to remove the deposits from the cathodes on a frequent basis using a manual maintenance procedure. The prior techniques have required manual removal of the cathodes from the processing equipment with associated cleaning and reinstallation back into the processing equipment. Such maintenance requirements have a very derogatory effect on production throughput because the machine is shut down and service is then performed. Even if the maintenance allows installation of new or substitute electrodes, the down-time is substantial and a significant economic loss for the semiconductor device manufacturer. 
     Thus, there is a need in the art for improved techniques, apparatus, and maintenance procedures for removing accumulated plating deposits from the electrodes of semiconductor plating systems. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred embodiments of the invention are described below with reference to the accompanying drawings, which are briefly described below. 
     FIG. 1 is an environmental view of the semiconductor processing head of the present invention showing two processing heads in a processing station, one in a deployed, “closed” or “processing” position, and one in an “open” or “receive wafer” position. 
     FIG. 2 is an isometric view of the semiconductor processing head of the present invention. 
     FIG. 3 is a side elevation view of the processing head of the present invention showing the head in a “receive wafer” position. 
     FIG. 4 is a side elevation view of the processing head of FIG. 3 showing the head in a rotated position ready to lower the wafer into the processing station. 
     FIG. 5 is a side elevation view of the processing head of FIG. 3 showing the head operator pivoted to deploy the processing head and wafer into the bowl of the processing station. 
     FIG. 6 is a schematic front elevation view of the processing head indicating the portions detailed in FIGS. 7 and 8. 
     FIG. 7 is a front elevation sectional view of the left half of the processing head of the apparatus of the present invention also showing a first embodiment of the wafer holding fingers. 
     FIG. 8 is a front elevation sectional view of the left half of the processing head of the apparatus of the present invention also showing a first embodiment of the wafer holding fingers. 
     FIG. 9 is an isometric view of the operator base and operator arm of the apparatus of the present invention with the protective cover removed. 
     FIG. 10 is a right side elevation view of the operator arm of the present invention showing the processing head pivot drive mechanism. 
     FIG. 11 is a left side elevation view of the operator arm of the present invention showing the operator arm drive mechanism. 
     FIG. 12 is schematic plan view of the operator arm indicating the portions detailed in FIGS. 13 and 14. 
     FIG. 13 is a partial sectional plan view of the right side of the operator arm showing the processing head drive mechanism. 
     FIG. 14 is a partial sectional plan view of the left side of the operator arm showing the operator arm drive mechanism. 
     FIG. 15 is a side elevational view of a semiconductor workpiece holder constructed according to a preferred aspect of the invention. 
     FIG. 16 is a front sectional view of the FIG. 1 semiconductor workpiece holder. 
     FIG. 17 is a top plan view of a rotor which is constructed in accordance with a preferred aspect of this invention, and which is taken along line  3 — 3  in FIG.  16 . 
     FIG. 18 is an isolated side sectional view of a finger assembly constructed in accordance with a preferred aspect of the invention and which is configured for mounting upon the FIG. 17 rotor. 
     FIG. 19 is a side elevational view of the finger assembly of FIG.  18 . 
     FIG. 20 is a fragmentary cross-sectional enlarged view of a finger assembly and associated rotor structure. 
     FIG. 21 is a view taken along line  7 — 7  in FIG.  4  and shows a portion of the preferred finger assembly moving between an engaged and disengaged position. 
     FIG. 22 is a view of a finger tip of the preferred finger assembly and shows an electrode tip in a retracted or disengaged position (solid lines) and an engaged position (phantom lines) against a semiconductor workpiece. 
     FIG. 23 is a sectional view showing a second embodiment semiconductor processing station having a workpiece support assembly and a plating station bowl assembly. 
     FIG. 24 is an enlarged sectional view similar to FIG. 23 showing only portions of the workpiece support. 
     FIG. 25 is an exploded perspective view of portions of the workpiece support shown in FIG.  24 . 
     FIG. 26 is an exploded perspective view of portions of a rotor assembly forming part of the workpiece support shown in FIG.  24 . 
     FIG. 27 is a perspective view showing an interior face of the rotor assembly. 
     FIG. 28 is a perspective view showing the interior face of the rotor assembly with a wafer supported thereon. 
     FIG. 29 is an enlarged perspective view showing an actuator transmission which mounts on the rotor assembly and controls motion of workpiece-engaging fingers. 
     FIG. 30 is an exploded perspective assembly view of the actuator transmission shown in FIG.  29 . 
     FIG. 31 is a longitudinal sectional view of the actuator transmission shown in FIG.  29 . 
     FIG. 32 is a longitudinal sectional view of one preferred form of electrode assembly which can be used in the second embodiment processing system. 
     FIG. 33 is a longitudinal sectional view of one preferred form of electrode assembly which can be used in the second embodiment processing system. 
     FIG. 34 is a longitudinal sectional view of one preferred form of electrode assembly which can be used in the second embodiment processing system. 
     FIG. 35 is a longitudinal sectional view of one preferred form of electrode assembly which can be used in the second embodiment processing system. 
     FIG. 36 is a longitudinal sectional view of one preferred form of electrode assembly which can be used in the second embodiment processing system. 
     FIG. 37 is a sectional view showing an enlarged distal tip portion of a further electrode before being pre-conditioned in accordance with another aspect of the invention. 
     FIG. 38 is a sectional view showing the enlarge distal tip portion of the previous figure after being pre-conditioned. 
     FIG. 39 is a longitudinal sectional view of one preferred form of electrode assembly which can be used in the second embodiment processing system. 
     FIG. 40 is a sectional view showing the electrode assembly of FIG. 39 in position ready to engage a semiconductor workpiece. 
     FIG. 41 is a sectional view showing the electrode assembly of FIG. 39 in an engaged position with a semiconductor workpiece. 
     FIG. 42 is a longitudinal sectional view showing the plating station bowl shown in FIG.  23 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     This disclosure of the invention is submitted in furtherance of the constitutional purposes of the U.S. Patent Laws “to promote the progress of science and useful arts” (Article 1, Section 8). 
     
       
         
               
             
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 Listing of Subsections of Detailed Description and 
               
               
                 Pertinent Items with Reference Numerals and Page Numbers 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 
                   Workpiece Support 
                 
                 11 
               
               
                   
                 semiconductor processing machine 400 
                 11 
               
               
                   
                 workpiece supports 401 
                 11 
               
               
                   
                 Workpiece support 402 
                 11 
               
               
                   
                 Workpiece support 403 
                 11 
               
               
                   
                 semiconductor manufacturing chamber 404 
                 11 
               
               
                   
                 beam emitter 81 
                 11 
               
               
                   
                 operator base 405 
                 12 
               
               
                   
                 processing head 406 
                 12 
               
               
                   
                 operator arm 407 
                 12 
               
               
                   
                 wafer holder 408 
                 12 
               
               
                   
                 fingers 409 
                 12 
               
               
                   
                 Workpiece holder 408 
                 12 
               
               
                   
                 workpiece spin axis 410 
                 12 
               
               
                   
                 process pivot axis 411 
                 12 
               
               
                   
                 operator pivot axis 412 
                 12 
               
               
                   
                 workpiece W 
                 12 
               
               
                   
                 fingertips 414 
                 12 
               
               
                   
                 processing bowl 417 
                 13 
               
               
                   
                 left and right forks 418 and 419 
                 14 
               
               
                   
                 
                   Operator Base 
                 
                 14 
               
               
                   
                 operator base back portion 420 
                 14 
               
               
                   
                 operator base left yoke arm 421 
                 14 
               
               
                   
                 operator base right yoke arm 422 
                 14 
               
               
                   
                 yoke arm fasteners 423 
                 14 
               
               
                   
                 operator arm bearings 424 
                 15 
               
               
                   
                 operator arm 425 
                 15 
               
               
                   
                 
                   Operator Arm 
                 
                 15 
               
               
                   
                 process arm rear cavity 426 
                 15 
               
               
                   
                 lift motor 452 
                 15 
               
               
                   
                 rotate motor 428 
                 15 
               
               
                   
                 processing head left pivot shaft 429 
                 16 
               
               
                   
                 processing head right pivot shaft 430 
                 16 
               
               
                   
                 
                   Operator Arm-Processing Head Rotate 
                 
               
               
                   
                 
                   Mechanism 
                 
                 16 
               
               
                   
                 Processing head rotate mechanism 431 
                 16 
               
               
                   
                 rotate shaft 432 
                 16 
               
               
                   
                 securing collar 433 
                 16 
               
               
                   
                 rotate motor support 434 
                 17 
               
               
                   
                 rotate encoder 435 
                 17 
               
               
                   
                 rotate pulley inboard bearing 436 
                 17 
               
               
                   
                 rotate belt 437 
                 18 
               
               
                   
                 processing head pulley 438 
                 18 
               
               
                   
                 rotate belt tensioner 439 
                 18 
               
               
                   
                 tensioner hub 468 
                 19 
               
               
                   
                 processing head shaft bearing 440 
                 19 
               
               
                   
                 processing head rotate bearing 469 
                 19 
               
               
                   
                 processing head shaft bearing 441 
                 19 
               
               
                   
                 cable brackets 442 and 443 
                 19 
               
               
                   
                 rotate overtravel protect 444 
                 20 
               
               
                   
                 rotate flag 447 
                 20 
               
               
                   
                 Rotate optical switches 445 and 446 
                 20 
               
               
                   
                 
                   Operator Arm-Lift Mechanism 
                 
                 21 
               
               
                   
                 operator arm lift mechanism 448 
                 21 
               
               
                   
                 lift motor shaft 454 
                 21 
               
               
                   
                 lift gear drive 453 
                 22 
               
               
                   
                 lift drive shaft 456 
                 22 
               
               
                   
                 lift bushing 449 
                 22 
               
               
                   
                 anchor plate 458 
                 22 
               
               
                   
                 anchor fasteners 457 
                 22 
               
               
                   
                 Lift bearing 450 
                 22 
               
               
                   
                 lift bearing support 460 
                 22 
               
               
                   
                 operator arm frame 461 
                 22 
               
               
                   
                 lift anchor 451 
                 22 
               
               
                   
                 lift overtravel protect 462 
                 23 
               
               
                   
                 lift optical switch low 463 
                 23 
               
               
                   
                 lift optical switch high 464 
                 23 
               
               
                   
                 lift flag 465 
                 23 
               
               
                   
                 lift motor encoder 455 
                 24 
               
               
                   
                 lift motor 452 
                 24 
               
               
                   
                 slotted lift flag mounting slots 467 
                 24 
               
               
                   
                 lift flag fasteners 466 
                 24 
               
               
                   
                 
                   Processing Head 
                 
                 24 
               
               
                   
                 processing head housing 470 
                 24 
               
               
                   
                 circumferential grooves 471 
                 25 
               
               
                   
                 rotate shaft openings 474 and 475 
                 25 
               
               
                   
                 left and right processing head mounts 472 
                 25 
               
               
                   
                 processing head door 476 
                 25 
               
               
                   
                 processing head void 477 
                 25 
               
               
                   
                 
                   Processing Head Spin Motor 
                 
                 26 
               
               
                   
                 workpiece holder 478 
                 26 
               
               
                   
                 spin axis 479 
                 26 
               
               
                   
                 spin motor 480 
                 26 
               
               
                   
                 top motor housing 481 
                 26 
               
               
                   
                 spin motor shaft 483 
                 27 
               
               
                   
                 workpiece holder rotor 484 
                 27 
               
               
                   
                 rotor hub 485 
                 27 
               
               
                   
                 rotor hub recess 486 
                 27 
               
               
                   
                 workpiece shaft snap-ring 488 
                 27 
               
               
                   
                 rotor recess groove 489 
                 27 
               
               
                   
                 spin encoder 498 
                 28 
               
               
                   
                 optical tachometer 499 
                 28 
               
               
                   
                 
                   Processing Head Finger Actuators 
                 
                 30 
               
               
                   
                 Pneumatic piston 502 
                 30 
               
               
                   
                 actuator spring 505 
                 30 
               
               
                   
                 cavity end cap 507 
                 30 
               
               
                   
                 retaining ring 508 
                 31 
               
               
                   
                 pneumatic inlet 503 
                 31 
               
               
                   
                 pneumatic supply line 504 
                 31 
               
               
                   
                 actuator plate 509 
                 31 
               
               
                   
                 actuator plate connect screw 510 
                 31 
               
               
                   
                 Wave springs 529 
                 31 
               
               
                   
                 bushing 512 
                 31 
               
               
                   
                 pneumatic piston recess 511 
                 31 
               
               
                   
                 finger actuator contacts 513 
                 32 
               
               
                   
                 
                   Processing Head Workpiece Holder 
                 
                 32 
               
               
                   
                 finger actuator lever 514 
                 32 
               
               
                   
                 finger stem 515 
                 32 
               
               
                   
                 finger diaphragm 519 
                 32 
               
               
                   
                 workpiece holder rotor 484 
                 32 
               
               
                   
                 finger opening 521 
                 32 
               
               
                   
                 rotor diaphragm lip 523 
                 33 
               
               
                   
                 finger spring 520 
                 33 
               
               
                   
                 finger actuator tab 522 
                 33 
               
               
                   
                 finger collar or nut 517 
                 33 
               
               
                   
                 shoulder 518 
                 33 
               
               
                   
                 finger actuator mechanism 500 
                 33 
               
               
                   
                 cavity 501 
                 34 
               
               
                   
                 
                   Semiconductor Workpiece Holder - 
                 
                 34 
               
               
                   
                 
                   Electroplating Embodiment 
                 
               
               
                   
                 semiconductor workpiece holder 810 
                 34 
               
               
                   
                 bottom half or bowl 811 
                 34 
               
               
                   
                 
                   Processing Head and Processing Head 
                 
                 35 
               
               
                   
                 
                   Operator 
                 
               
               
                   
                 workpiece support 812 
                 35 
               
               
                   
                 spin head assembly 814 
                 35 
               
               
                   
                 lift/rotate assembly 816 
                 35 
               
               
                   
                 motor 818 
                 36 
               
               
                   
                 rotor 820 
                 36 
               
               
                   
                 rotor spin axis 822 
                 36 
               
               
                   
                 finger assembly 824 
                 36 
               
               
                   
                 actuator 825 
                 36 
               
               
                   
                 rotor center piece 826 
                 37 
               
               
                   
                 spokes 828 
                 37 
               
               
                   
                 rotor perimeter piece 830 
                 37 
               
               
                   
                 
                   Finger Assembly 
                 
                 38 
               
               
                   
                 finger assembly frame 832 
                 38 
               
               
                   
                 angled slot 832a 
                 39 
               
               
                   
                 flnger assembly frame outer flange 834 
                 39 
               
               
                   
                 inner drive plate portion 836 
                 39 
               
               
                   
                 
                   Finger Assembly Drive System 
                 
                 39 
               
               
                   
                 bearing 838 
                 39 
               
               
                   
                 collet 840 
                 39 
               
               
                   
                 bearing receptacle 839 
                 39 
               
               
                   
                 spring 842 
                 40 
               
               
                   
                 spring seat 844 
                 40 
               
               
                   
                 
                   Finger Assembly Electrical System 
                 
                 40 
               
               
                   
                 pin connector 846 
                 40 
               
               
                   
                 finger 848 
                 40 
               
               
                   
                 nut 850 
                 41 
               
               
                   
                 anti-rotation pin 852 
                 41 
               
               
                   
                 finger tip 854 
                 41 
               
               
                   
                 electrode contact 858 
                 41 
               
               
                   
                 
                   Finger Assembly Drive System Interface 
                 
                 42 
               
               
                   
                 finger actuator 
                 42 
               
               
                   
                 actuation ring 863 
                 42 
               
               
                   
                 first movement path axis 864 
                 43 
               
               
                   
                 secondary linkage 865 
                 43 
               
               
                   
                 link arm 867 
                 43 
               
               
                   
                 actuator torque ring 869 
                 43 
               
               
                   
                 pneumatic operator 871 
                 43 
               
               
                   
                 
                   Engaged and Disengaged Positions 
                 
                 44 
               
               
                   
                 arrow A 
                 44 
               
               
                   
                 workpiece standoff 865 
                 45 
               
               
                   
                 bend 866 
                 45 
               
               
                   
                 
                   Finger Assembly Seal 
                 
                 46 
               
               
                   
                 seal 868 
                 46 
               
               
                   
                 rim portion 870 
                 46 
               
               
                   
                 
                   Methods and Operation 
                 
                 47 
               
               
                   
                 
                   Second Embodiment Processing Station - 
                 
                 53 
               
               
                   
                 
                   Generally 
                 
               
               
                   
                 second semiconductor processing station 900 
                 53 
               
               
                   
                 workpiece support assembly 901 
                 53 
               
               
                   
                 processing bowl 917 
                 53 
               
               
                   
                 processing or manufacturing chamber 904 
                 54 
               
               
                   
                 
                   Workpiece Support Generally 
                 
                 54 
               
               
                   
                 rotor assembly 984 
                 54 
               
               
                   
                 
                   Workpiece Support Head Operator 
                 
                 54 
               
               
                   
                 processing head 906 
                 54 
               
               
                   
                 head operator 907 
                 54 
               
               
                   
                 upper portion 908 
                 54 
               
               
                   
                 head connection shaft 909 
                 54 
               
               
                   
                 horizontal pivot axis 910 
                 54 
               
               
                   
                 
                   Workpiece Support Main Part 
                 
                 55 
               
               
                   
                 processing head housing 970 
                 55 
               
               
                   
                 processing head frame 982 
                 55 
               
               
                   
                 door plate 983 
                 55 
               
               
                   
                 door ring member 984 
                 55 
               
               
                   
                 frame-pivot shaft connection 985 
                 55 
               
               
                   
                 pivot shaft connection base 935 
                 55 
               
               
                   
                 first housing part 971 
                 56 
               
               
                   
                 housing cap 972 
                 56 
               
               
                   
                 main part mechanism chamber 973 
                 56 
               
               
                   
                 peripheral groove 986 
                 56 
               
               
                   
                 inflatable door seal 987 
                 56 
               
               
                   
                 annular rotor receiving groove 988 
                 56 
               
               
                   
                 
                   Workpiece Support Rotor Drive 
                 
                 57 
               
               
                   
                 workpiece spin motor 980 
                 57 
               
               
                   
                 stator armatures 916 
                 57 
               
               
                   
                 motor shaft 918 
                 57 
               
               
                   
                 bottom motor bearing 921 
                 57 
               
               
                   
                 bottom motor housing 922 
                 57 
               
               
                   
                 top motor housing 923 
                 57 
               
               
                   
                 top motor bearing 927 
                 57 
               
               
                   
                 fasteners 924 
                 57 
               
               
                   
                 frame extensions 925 
                 57 
               
               
                   
                 top frame piece 926 
                 58 
               
               
                   
                 
                   Workpiece Support Rotor Assembly 
                 
                 58 
               
               
                   
                 rotor assembly 930 
                 58 
               
               
                   
                 rotor shaft 931 
                 58 
               
               
                   
                 rotor shaft hub 932 
                 58 
               
               
                   
                 shaft hub receptacle 933 
                 58 
               
               
                   
                 inner rotor part 934 
                 58 
               
               
                   
                 inner rotor part hub 935 
                 58 
               
               
                   
                 peripheral band 936 
                 58 
               
               
                   
                 snap-ring 937 
                 58 
               
               
                   
                 transmission receptacles 937 
                 58 
               
               
                   
                 fasteners 941 
                 59 
               
               
                   
                 rotor face panel 943 
                 59 
               
               
                   
                 apertures 787 
                 59 
               
               
                   
                 support standoffs 721 
                 59 
               
               
                   
                 workpiece peripheral guide pins 722 
                 59 
               
               
                   
                 reinforcing ribs 942 
                 59 
               
               
                   
                 side wall 944 
                 59 
               
               
                   
                 finger passageways 949 
                 60 
               
               
                   
                 rotor shaft mounting nut 888 
                 60 
               
               
                   
                 angular position encoder 498 
                 60 
               
               
                   
                 
                   Workpiece Detection Subsystem 
                 
                 61 
               
               
                   
                 mounting 738 
                 61 
               
               
                   
                 detector 739 
                 61 
               
               
                   
                 workpiece detector windows 741 
                 62 
               
               
                   
                 
                   Workpiece Support Finger Actuator 
                 
                 63 
               
               
                   
                 finger pivot axes 953 
                 64 
               
               
                   
                 workpiece standoff supports 721 
                 64 
               
               
                   
                 finger actuator transmission 960 
                 65 
               
               
                   
                 finger head mounting receptacle 954 
                 65 
               
               
                   
                 locking pin groove 955 
                 65 
               
               
                   
                 finger mounting pin 956 
                 65 
               
               
                   
                 transmission base 961 
                 65 
               
               
                   
                 mounting cutout 962 
                 65 
               
               
                   
                 transmission shaft 963 
                 65 
               
               
                   
                 shaft channel or groove 964 
                 66 
               
               
                   
                 shaft camming control member 965 
                 66 
               
               
                   
                 ball 966 
                 66 
               
               
                   
                 ball support fastener 967 
                 66 
               
               
                   
                 interior shaft passageway 968 
                 66 
               
               
                   
                 spring retainer 969 
                 66 
               
               
                   
                 finger mounting spring 938 
                 66 
               
               
                   
                 set screw 939 
                 66 
               
               
                   
                 transmission head 656 
                 66 
               
               
                   
                 bearing 657 
                 66 
               
               
                   
                 head pieces 658 and 659 
                 67 
               
               
                   
                 head fasteners 660 
                 67 
               
               
                   
                 head guide rods 661 
                 67 
               
               
                   
                 two guide passageways 662 
                 67 
               
               
                   
                 head bias springs 664 
                 67 
               
               
                   
                 shaft seal 667 
                 67 
               
               
                   
                 transmission head depression ring 683 
                 67 
               
               
                   
                 operator output connection ring 684 
                 67 
               
               
                   
                 pneumatic actuator engines 691 
                 67 
               
               
                   
                 pneumatic manifolds 692 
                 67 
               
               
                   
                 
                   Electrode Fingers With Submerged 
                 
                 68 
               
               
                   
                 
                   Conductive Current Transfer Areas 
                 
               
               
                   
                 finger assembly 631 
                 68 
               
               
                   
                 finger shaft 632 
                 68 
               
               
                   
                 finger head 633 
                 68 
               
               
                   
                 locking pin 956 
                 68 
               
               
                   
                 dielectric sheathing 634 and 635 
                 68 
               
               
                   
                 contact head 636 
                 68 
               
               
                   
                 contact face 637 
                 68 
               
               
                   
                 submersion line 639 
                 69 
               
               
                   
                 first electrically conductive segment 642 
                 69 
               
               
                   
                 second electrically conductive segment 643 
                 69 
               
               
                   
                 third electrically conductive segment 644 
                 69 
               
               
                   
                 third dielectric segment 653 
                 70 
               
               
                   
                 third dielectric sheath 654 
                 70 
               
               
                   
                 distal contact insert part 655 
                 70 
               
               
                   
                 insert receptacle 616 
                 70 
               
               
                   
                 contact face 617 
                 70 
               
               
                   
                 electrode finger 979 
                 71 
               
               
                   
                 dielectric sheath 621 
                 71 
               
               
                   
                 
                   Electrode Fingers With Dielectric Sheaths 
                 
                 72 
               
               
                   
                 
                   Covering Submerged Areas 
                 
               
               
                   
                 electrode finger 681 
                 72 
               
               
                   
                 dielectric sheath 682 
                 72 
               
               
                   
                 contact insert side walls 619 
                 72 
               
               
                   
                 insert contact part or tip 655 
                 73 
               
               
                   
                 
                   Pre-Conditioning of Electrode Contact Faces 
                 
                 74 
               
               
                   
                 electrode 614 
                 74 
               
               
                   
                 distal exposed surface 615 
                 74 
               
               
                   
                 dielectric sheath 616 
                 74 
               
               
                   
                 
                   Methods Using Workpiece-Engaging 
                 
                 76 
               
               
                   
                 
                   Electrode Assembly With Sealing Boot 
                 
               
               
                   
                 electrode finger 583 
                 76 
               
               
                   
                 electrode shaft 584 
                 76 
               
               
                   
                 head 633 
                 76 
               
               
                   
                 cover or boot 585 
                 76 
               
               
                   
                 distal contact lip 586 
                 76 
               
               
                   
                 contact insert part 655 
                 76 
               
               
                   
                 skirt portion 587 
                 76 
               
               
                   
                 electrode shaft distal end surface 588 
                 76 
               
               
                   
                 contact face 617 
                 76 
               
               
                   
                 substrate or other subjacent layer 561 
                 77 
               
               
                   
                 thin metallic seed layer 562 
                 77 
               
               
                   
                 via or other opening 563 
                 77 
               
               
                   
                 photoresist layer 564 
                 77 
               
               
                   
                 
                   Plating Bowl Assembly 
                 
                 80 
               
               
                   
                 electroplating bowl assembly 303 
                 80 
               
               
                   
                 process bowl or plating vessel 316 
                 80 
               
               
                   
                 outer bowl side wall 617 
                 80 
               
               
                   
                 bowl bottom 319 
                 80 
               
               
                   
                 bowl rim assembly 314 
                 80 
               
               
                   
                 cup assembly 320 
                 80 
               
               
                   
                 fluid cup portion 321 
                 80 
               
               
                   
                 cup side 322 
                 80 
               
               
                   
                 cup bottom 323 
                 80 
               
               
                   
                 flutes 372 
                 80 
               
               
                   
                 cup main joint 387 
                 80 
               
               
                   
                 riser tube 361 
                 80 
               
               
                   
                 fitting 362 
                 81 
               
               
                   
                 fluid inlet line 325 
                 81 
               
               
                   
                 bowl bottom opening 327 
                 81 
               
               
                   
                 cup fluid inlet openings 324 
                 81 
               
               
                   
                 overflow chamber 345 
                 81 
               
               
                   
                 level detectors 351 and 352 
                 81 
               
               
                   
                 diffuser height adjustment mechanisms 386 
                 82 
               
               
                   
                 mounting fasteners 389 
                 82 
               
               
                   
                 
                   Plating Anode Shield 
                 
                 82 
               
               
                   
                 anode shield 393 
                 82 
               
               
                   
                 anode shield fasteners 394 
                 82 
               
               
                   
                   
               
             
          
         
       
     
     Workpiece Support 
     Turning now to FIG. 1, a semiconductor processing machine  400  having two workpiece supports  401  is shown. Workpiece support  402  is shown in a “open” or “receive wafer” position in order to receive a workpiece or semiconductor wafer for further processing. Workpiece support  403  is shown in a “closed” or “deployed” position wherein the semiconductor wafer has been received by the workpiece support and is being exposed to the semiconductor manufacturing process in the semiconductor manufacturing chamber  404 . FIG. 1 also shows an optional beam emitter  81  for emitting a laser beam detected by robotic wafer conveyors to indicate position of the unit. 
     Turning now to FIG. 2, an enlarged view of the workpiece support  401  is shown. Workpiece support  401  advantageously includes operator base  405 , a processing head  406 , and an operator arm  407 . Processing head  406  preferably includes workpiece holder or wafer holder  408  and which further includes fingers  409  for securely holding the workpiece during further process and manufacturing steps. Workpiece holder  408  more preferably spins about workpiece spin axis  410 . 
     The processing head is advantageously rotatable about processing head pivot axis or, more briefly termed, process pivot axis  411 . In this manner, a workpiece (not shown) may be disposed between and grasped by the fingers  409 , at which point the processing head is preferably rotated about process head pivot axis  411  to place the workpiece in a position to be exposed to the manufacturing process. 
     In the preferred embodiment, operator arm  407  may be pivoted about operator pivot axis  412 . In this manner, the workpiece is advantageously lowered into the process bowl (not shown) to accomplish a step in the manufacture of the semiconductor wafer. 
     Turning now to FIGS. 3-5, the sequence of placing a workpiece on the workpiece support and exposing the workpiece to the semiconductor manufacturing process is shown. In FIG. 3, a workpiece W is shown as being held in place by fingertips  414  of fingers  409 . Workpiece W is grasped by fingertips  414  after being placed in position by robot or other means. 
     Once the workpiece W has been securely engaged by fingertips  414 , processing head  406  can be rotated about process head pivot axis  411  as shown in FIG.  4 . Process head  406  is preferably rotated about axis  411  until workpiece W is at a desired angle, such as approximately horizontal. The operator arm  407  is pivoted about operator arm pivot axis  412  in a manner so as to coordinate the angular position of processing head  406 . In the closed position, the processing head is placed against the rim of bowl  416  and the workpiece W is essentially in a horizontal plane. Once the workpiece W has been secured in this position, any of a series of various semiconductor manufacturing process steps may be applied to the workpiece as it is exposed in the processing bowl  417 . 
     Since the processing head  406  is engaged by the operator arm  407  on the left and right side by the preferably horizontal axis  411  connecting the pivot points of processing head  406 , a high degree of stability about the horizontal plane is obtained. Further, since the operator arm  407  is likewise connected to the operator base  405  at left and right sides along the essentially horizontal line  412  connecting the pivot points of the operator arm, the workpiece support forms a structure having high rigidity in the horizontal plane parallel to and defined by axes  411  and  412 . Finally, since operator base  405  is securely attached to the semiconductor process machine  400 , rigidity about the spin axis  410  is also achieved. 
     Similarly, since processing head  406  is nested within the fork or yoke shaped operator arm  407  having left and right forks  418  and  419 , respectively, as shown in FIG. 2, motion due to cantilevering of the processing head is reduced as a result of the reduced moment arm defined by the line connecting pivot axes  411  and  412 . 
     In a typical semiconductor manufacturing process, the workpiece holder  408  will rotate the workpiece, having the process head  406  secured at two points, that is, at the left and right forks  418  and  419 , respectively, the vibration induced by the rotation of the workpiece holder  408  will be significantly reduced along the axis  411 . 
     A more complete description of the components of the present invention and their operation and interrelation follows. 
     Operator Base 
     Turning now to FIG. 9, operator base  405  is shown. The present invention advantageously includes an operator base  405  which forms an essentially yoke-shaped base having an operator base back portion  420 , an operator base left yoke arm  421 , and an operator base right yoke arm  422 . Yoke arms  421  and  422  are securely connected to the base of the yoke  420 . In the preferred embodiment, the yoke arms are secured to the yoke base by the yoke arm fasteners  423 . The yoke arm base in turn is advantageously connected to the semiconductor process machine  400  as shown in FIG.  1 . 
     The upper portions of the yoke arm advantageously include receptacles for housing the operator arm bearings  424  which are used to support the pivot shafts of the operator arm  425 , described more fully below. 
     Operator Arm 
     Still viewing FIG. 9, the present invention advantageously includes an operator arm  407 . As described previously, operator arm  407  preferably pivots about the operator arm pivot axis  412  which connects the center line defined by the centers of operator arm pivot bearings  424 . 
     Operator arm or pivot arm  407  is advantageously constructed in such a manner to reduce mass cantilevered about operator arm pivot axis  412 . This allows for quicker and more accurate positioning of the pivot arm as it is moved about pivot arm axis  412 . 
     The left fork of the pivot arm  418 , shown more clearly in FIG. 11, houses the mechanism for causing the pivot arm to lift or rotate about pivot arm pivot axis  412 . Pivot arm right fork  419 , shown more clearly in FIG. 10, houses the mechanism for causing the processing head  406  (not shown) to rotate about the process head pivot axis  411 . 
     The process arm rear cavity  426 , shown in FIG. 9, houses the lift motor  452  for causing the operator arm  407  to rotate about pivot arm axis  412 . Process arm rear cavity  426  also houses rotate motor  428  which is used to cause the processing head  406  to rotate about the processing head pivot axis  411 . The rotate motor  428  may more generally be described as a processing head pivot or rotate drive. Processing head  406  is mounted to operator arm  407  at processing head left pivot shaft  429  and processing head right pivot shaft  430 . 
     Operator arm  407  is securely attached to left yoke arm  421  and right yoke arm  422  by operator arm pivot shafts  425  and operator arm pivot bearings  424 , the right of which such bearing shaft and bearings are shown in FIG.  9 . 
     Operator Arm-Processing Head Rotate Mechanism 
     Turning now to FIG. 13, a sectional plan view of the right rear corner of operator arm  407  is shown. The right rear section of operator arm  407  advantageously contains the rotate mechanism which is used to rotate processing head  406  about processing head pivot shafts  430  and  429 . Processing head rotate mechanism  431  preferably consists of rotate motor  428  which drives rotate shaft  432 , more generally described as a processing head drive shaft. Rotate shaft  432  is inserted within rotate pulley  425  which also functions as the operator arm pivot shaft. As described previously, the operator arm pivot shaft/lift pulley is supported in operator arm pivot bearings  424 , which are themselves supported in operator base yoke arm  422 . Rotate shaft  432  is secured within left pulley  424  by securing collar  433 . Securing collar  433  secures rotate pulley  425  to rotate shaft  432  in a secure manner so as to assure a positive connection between rotate motor  428  and rotate pulley  425 . An inner cover  584  is also provided. 
     Rotate motor  428  is disposed within process arm rear cavity  426  and is supported by rotate motor support  434 . Rotate motor  428  preferably is a servo allowing for accurate control of speed and acceleration of the motor. Servo motor  428  is advantageously connected to rotate encoder  435  which is positioned on one end of rotate motor  428 . Rotate encoder  435 , more generally described as a processing head encoder, allows for accurate measurement of the number of rotations of rotate motor  428 , as well as the position, speed, and acceleration of the rotate shaft  432 . The information from the rotate encoder may be used in a rotate circuit which may then be used to control the rotate motor when the rotate motor is a servo. This information is useful in obtaining the position and rate of travel of the processing head, as well as controlling the final end point positions of the processing head as it is rotated about process head rotate axis  411 . 
     The relationship between the rotate motor rotations, as measured by rotate encoder  435 , may easily be determined once the diameters of the rotate pulley  425  and the processing head pulley  438  are known. These diameters can be used to determine the ratio of rotate motor relations to processing head rotations. This may be accomplished by a microprocessor, as well as other means. 
     Rotate pulley  425  is further supported within operator arm  407  by rotate pulley inboard bearing  436  which is disposed about an extended flange on the rotate pulley  425 . Rotate pulley inboard bearing  436  is secured by the body of the operator arm  407 , as shown in FIG.  13 . 
     Rotate pulley  425  advantageously drives rotate belt  437 , more generally described as a flexible power transmission coupling. Referring now to FIG. 10, rotate belt  437  is shown in the side view of the right arm  419  of the operator arm  407 . Rotate belt  437  is preferably a toothed timing belt to ensure positive engagement with the processing head drive wheel, more particularly described herein as the processing head pulley  438 , (not shown in this view). In order to accommodate the toothed timing belt  437 , both the rotate pulley  425  and the processing head pulley  438  are advantageously provided with gear teeth to match the tooth pattern of the timing belt to assure positive engagement of the pulleys with the rotate belt. 
     Rotate mechanism  431  is preferably provided with rotate belt tensioner  439 , useful for adjusting the belt to take up slack as the belt may stretch during use, and to allow for adjustment of the belt to assure positive engagement with both the rotate pulley and the processing head pulley. Rotate belt tensioner  439  adjusts the tension of rotate belt  437  by increasing the length of the belt path between rotate pulley  425  and processing head pulley  438 , thereby accommodating any excess length in the belt. Inversely, the length of the belt path may also be shortened by adjusting rotate belt tensioner  439  so as to create a more linear path in the upper portion of rotate belt  437 . The tensioner  439  is adjusted by rotating it about tensioner hub  468  and securing it in a new position. 
     Turning now to FIG. 13, processing head pulley  438  is mounted to processing head rotate shaft  430  in a secured manner so that rotation of processing head pulley  438  will cause processing head rotate shaft  430  to rotate. Processing head shaft  430  is mounted to operator arm right fork  419  by processing head shaft bearing  440 , which in turn is secured in the frame of the right fork  419  by processing head rotate bearing  469 . In a like manner, processing head shaft  429  is mounted in operator arm left fork  418  by processing head shaft bearing  441 , as shown in FIG.  9 . 
     Processing head pivot shafts  430  and  429  are advantageously hollow shafts. This feature is useful in allowing electrical, optical, pneumatic, and other signal and supply services to be provided to the processing head. Service lines such as those just described which are routed through the hollow portions of processing head pivot shafts  429  and  430  are held in place in the operator arms by cable brackets  442  and  443 . Cable brackets  442  and  443  serve a dual purpose. First, routing the service lines away from operating components within the operator arm left and right forks. Second, cable brackets  442  and  443  serve a useful function in isolating forces imparted to the service cables by the rotating action of processing head  406  as it rotates about processing head pivot shafts  429  and  430 . This rotating of the processing head  406  has the consequence that the service cables are twisted within the pivot shafts as a result of the rotation, thereby imparting forces to the cables. These forces are preferably isolated to a particular area so as to minimize the effects of the forces on the cables. The cable brackets  442  and  443  achieve this isolating effect. 
     The process head rotate mechanism  431 , shown in FIG. 13, is also advantageously provided with a rotate overtravel protect  444 , which functions as a rotate switch. Rotate overtravel protect  444  preferably acts as a secondary system to the rotate encoder  435  should the control system fail for some reason to stop servo  428  in accordance with a predetermined position, as would be established by rotate encoder  435 . Turning to FIG. 13, the rotate overtravel protect  444  is shown in plan view. The rotate overtravel protect preferably consists of rotate optical switches  445  and  446 , which are configured to correspond to the extreme (beginning and end point) portions of the processing head, as well as the primary switch component which preferably is a rotate flag  447 . Rotate flag  447  is securely attached to processing head pulley  438  such that when processing head shaft  430  (and consequently processing head  406 ) are rotated by virtue of drive forces imparted to the processing head pulley  425  by the rotate belt  437 , the rotate flag  447  will rotate thereby tracking the rotate motion of processing head  406 . Rotate optical switches  445  and  446  are positioned such that rotate flag  447  may pass within the optical path generated by each optical switch, thereby generating a switch signal. The switch signal is used to control an event such as stopping rotate motor  428 . Rotate optical switch  445  will guard against overtravel of processing head  406  in one direction, while rotate optical switch  446  will provide against overtravel of the processing head  406  in the opposite direction. 
     Operator Arm-Lift Mechanism 
     Operator arm  407  is also advantageously provided with an operator arm lift mechanism  448  which is useful for causing the operator arm to lift, that is, to pivot or rotate about operator arm pivot axis  412 . Turning to FIG. 14, the operator arm lift mechanism  448  is shown in the sectional plan view of the right rear corner of operator arm  407 . 
     Operator arm lift mechanism  448  is advantageously driven by lift motor  452 . Lift motor  452  may be more generally described as an operator arm drive or operator arm pivot drive. Lift motor  452  is preferably a servo motor and is more preferably provided with an operator encoder, more specifically described as lift motor encoder  456 . When lift motor  452  is a servo motor coupled with lift encoder  456 , information regarding the speed and absolute rotational position of the lift motor shaft  454  may be known from the lift encoder signal. Additionally, by virtue of being a servo mechanism, the angular speed and acceleration of lift motor  452  may be easily controlled by use of the lift signal by an electrical circuit. Such a lift circuit may be configured to generate desired lift characteristics (speed, angle, acceleration, etc.). FIG. 14 shows that the lift operator may also include a brake  455  which is used to safely stop the arm if power fails. 
     Lift motor  452  drives lift motor shaft  454  which in turn drives lift gear drive  453 . Lift gear drive  453  is a gear reduction drive to produce a reduced number of revolutions at lift drive shaft  456  as the function of input revolutions from lift motor shaft  454 . 
     Lift drive gear shaft  456  is secured to lift anchor  451  which is more clearly shown in FIG.  11 . Lift anchor  451  is preferably shaped to have at least one flat side for positively engaging lift bushing  449 . Lift anchor  451  is secured to lift drive shaft  456  by anchor plate  458  and anchor fasteners  457 . In this manner, when lift drive shaft  456  is rotated, it will positively engage lift bushing  449 . Returning to FIG. 14, it is seen that lift bushing  449  is mounted in operator left yoke arm  421 , and is thus fixed with respect to operator base  405 . Lift bearing  450  is disposed about the lift bushing shank and is supported in operator arm  407  by lift bearing support  460  which is a bushing configured to receive lift bearing  450  on a first end and to support lift gear drive  453  on a second end. Lift bearing support  460  is further supported within operator arm  407  by operator arm frame  461 . The lift arm is thus free to pivot about lift bushing  449  by virtue of lift bearing  450 . 
     In operation, as lift motor  452  causes lift gear drive  453  to produce rotations at gear drive shaft  456 , lift anchor  451  is forced against lift bushing  449  which is securely positioned within right operator yoke arm  421 . The reactive force against the lift anchor  451  will cause lift bearing support  460  to rotate relative to lift bushing  449 . Since lift bushing  449  is fixed in operator base  405 , and since operator base  405  is fixed to processing machine  400 , rotation of lift bearing support  460  will cause lift arm  407  to pivot about operator arm pivot axis  412 , thereby moving the processing head  406 . It is advantageous to consider the gear drive shaft (or “operator arm shaft”) as being, fixed with respect to operator base  405  when envisioning the operation of the lift mechanism. 
     Operator lift mechanism  448  is also advantageously provided with a lift overtravel protect  462  or lift switch. The lift rotate protect operates in a manner similar to that described for the rotate overtravel protect  444  described above. Turning now to FIG. 11, a left side view of the operator arm  407  is shown which shows the lift overtravel protect in detail. 
     The lift overtravel protect preferably includes a lift optical switch low  463  and a lift optical switch high  464 . Other types of limit switches can also be used. The switch high  464  and switch low  463  correspond to beginning and endpoint travel of lift arm  407 . The primary lift switch component is lift flag  465 , which is firmly attached to left operator base yoke arm  421 . The lift optical switches are preferably mounted to the movable operator arm  407 . As operator arm  407  travels in an upward direction in pivoting about operator arm pivot axis  412 , lift optical switch high  464  will approach the lift flag  465 . Should the lift motor encoder  455  fail to stop the lift motor  454  as desired, the lift flag  465  will break the optical path of the lift optical switch high  464  thus producing a signal which can be used to stop the lift motor. In like manner, when the operator arm  407  is being lowered by rotating it in a clockwise direction about the operator arm pivot axis  412 , as shown in FIG. 11, overtravel of operator arm  407  will cause lift optical switch low  463  to have its optical path interrupted by lift flag  465 , thus producing a signal which may be used to stop lift motor  452 . As is shown in FIG. 11, lift flag  465  is mounted, to left operator base yoke arm  421  with slotted lift flag mounting slots  467  and removable lift flag fasteners  466 . Such an arrangement allows for the lift flag to be adjusted so that the lift overtravel protect system only becomes active after the lift arm  407  has traveled beyond a preferred point. 
     Processing Head 
     Turning now to FIG. 6, a front elevation schematic view of the processing head  406  is shown. Processing head  406  is described in more detail in FIGS. 7 and 8. Turning now to FIG. 7, a sectional view of the left front side of processing head  406  is shown. Processing head  406  advantageously includes a processing head housing  470  and frame  582 . Processing head  406  is preferably round in shape in plan view allowing it to easily pivot about process head pivot axis  411  ,with no interference from operator arm  407 , as demonstrated in FIGS. 3-5. Returning to FIG. 7, processing head housing  470  more preferably has circumferential grooves  471  which are formed into the side of process head housing  470 . Circumferential grooves  471  have a functional benefit of increasing heat dissipation from processing head  406 . 
     The sides of processing head housing  470  are advantageously provided with rotate shaft openings  474  and  475  for receiving respectively left and right processing head pivot shafts  429  and  430 . Processing head pivot shafts  429  and  430  are secured to the processing head  406  by respective left and right processing head mounts,  472  and  473 . Processing head mounts  472  and  473  are affirmative connected to processing head frame  582  which also supports processing head door  476  which is itself securely fastened to processing head housing  470 . Consequently, processing head pivot shafts  429  and  430  are fixed with respect to processing head  407  and may therefore rotate or pivot with respect to operator arm  407 . The details of how processing head pivot shafts  429  and  430  are received within operator arm  407  were discussed supra. 
     Processing head housing  470  forms a processing head void  477  which is used to house additional processing head components such as the spin motor, the pneumatic finger actuators, and service lines, all discussed more fully below. 
     The processing head also advantageously includes a workpiece holder and fingers for holding a workpiece, as is also more fully described below. 
     Processing Head Spin Motor 
     In a large number of semiconductor manufacturing processes, is desirable to spin the semiconductor wafer or workpiece during the process, for example to assure even distribution of applied process fluids across the face of the semiconductor wafer, or to aid drying of the wafer after a wet chemistry process. It is therefore desirable to be able to rotate the semiconductor workpiece while it is held by the processing head. 
     The semiconductor workpiece is held during the process by workpiece holder  478  described more fully below. In order to spin workpiece holder  478  relative to processing head  406  about spin axis  479 , an electric, pneumatic, or other type of spin motor or workpiece spin drive is advantageously provided. 
     Turning to FIG. 8, spin motor  480  has armatures  526  which drive spin motor shaft  483  in rotational movement to spin workpiece holder  478 . Spin motor  480  is supported by bottom motor bearing  492  in bottom motor housing  482 . Bottom motor housing  482  is secured to processing head  406  by door  476 . Spin motor  480  is thus free to rotate relative to processing head housing  470  and door  476 . Spin motor  480  is preferably additionally held in place by top motor housing  481  which rests on processing head door  476 . Spin motor  480  is rotationally isolated from top motor housing  481  by top motor bearing  493 , which is disposed between the spin motor shaft  483  and top motor housing  481 . 
     The spin motor is preferably an electric motor which is provided with an electrical supply source through pivot shaft  429  and/or  430 . Spin motor  480  will drive spin motor shaft  483  about spin axis  479 . 
     To secure workpiece holder rotor  484  to spin motor shaft  483 , workpiece holder rotor  484  is preferably provided with a rotor hub  485 . Rotor hub  485  defines a rotor hub recess  486  which receives a flared end of workpiece holder shaft  491 . The flared end  487  of workpiece holder shaft  491  is secured within the rotor hub recess  486  by workpiece shaft snap-ring  488  which fits within rotor recess groove  489  above the flared portion  487  of workpiece holder shaft  491 . 
     The workpiece holder shaft  491  is fitted inside of spin motor shaft  483  and protrudes from the top of the spin motor shaft. The top of workpiece holder shaft  491  is threaded to receive thin nut  527  (see FIG.  7 ). Thin nut  527  is tightened against optical tachometer  499  (describe more fully below). Optical tachometer  499  is securely attached to spin motor shaft  483  such that as the spin motor  480  rotationally drives the spin motor shaft  483 , the workpiece holder shaft  491  is also driven. 
     Workpiece holders may be easily changed out to accommodate various configurations which may be required for the various processes encountered in manufacturing of the semiconductors. This is accomplished by removing spin encoder  498  (described below), and then thin nut  527 . Once the thin nut has been removed the workpiece holder  478  will drop away from the processing head  406 . 
     The processing head is also advantageously provided with a spin encoder  498 , more generally described as a workpiece holder encoder, and an optical tachometer  499 . As shown in FIG. 7, spin encoder  498  is mounted to top motor housing  481  by encoder support  528  so as to remain stationary with respect to the processing head  406 . Optical tachometer  499  is mounted on spin motor shaft  483  so as to rotate with the motor  480 . When operated in conjunction, the spin encoder  498  and optical tachometer  499  allow the speed, acceleration, and precise rotational position of the spin motor shaft (and therefore the workpiece holder  478 ) to be known. In this manner, and when spin motor  480  is provided as a servo motor, a high degree of control over the spin rate, acceleration, and rotational angular position of the workpiece with respect to the process head  407  may be obtained. 
     In one application of the present invention the workpiece support is used to support a semiconductor workpiece in an electroplating process. To accomplish the electroplating an electric current is provided to the workpiece through an alternate embodiment of the fingers (described more fully below). To provide electric current to the finger, conductive wires are run from the tops of the fingers inside of the workpiece holder  478  through the electrode wire holes  525  in the flared lower part of workpiece holder shaft  491 . The electrode wires are provided electric current from electrical lines run through processing pivot shaft  429  and/or  430 . 
     The electrical line run through pivot shaft  430 / 429  will by nature be stationary with respect to processing head housing  470 . However, since the workpiece holder rotor is intended to be capable of rotation during the electroplating process, the wires passing into workpiece support shaft  491  through electrode wire holes  525  may rotate with respect to processing head housing  470 . Since the rotating electrode wires within workpiece shaft  491  and the stationary electrical supply lines run through pivot shaft  430 / 429  must be in electrical communication, the rotational/stationary problem must be overcome. In the preferred embodiment, this is accomplished by use of electrical slip ring  494 . 
     Electrical slip ring  494 , shown in FIG. 7, has a lower wire junction  529  for receiving the conductive ends of the electrical wires passing into workpiece holder shaft  491  by electrode wire holes  525 . Lower wire junction  529  is held in place within workpiece holder shaft  491  by insulating cylindrical collar  497  and thus rotates with spin motor shaft  483 . The electrode wires terminate in a single electrical contact  531  at the top of the lower wire junction  529 . Electrical slip ring  494  further has a contact pad  530  which is suspended within the top of workpiece holder shaft  491 . Contact pad  530  is mechanically fastened to spin encoder  498 , which, as described previously, remains stationary with respect to processing head housing  470 . The stationary-to-rotational transition is made at the tip of contact pad  530 , which is in contact with the rotating electrical contact  531 . Contact pad  530  is electrically conductive and is in electrical communication with electrical contact  531 . In the preferred embodiment, contact pad  530  is made of copper-beryllium. A wire  585  carries current to finger assemblies when current supply is needed, such as on the alternative embodiment described below. 
     Processing Head Finger Actuators 
     Workpiece holder  478 , described more fully below, advantageously includes fingers for holding the workpiece W in the workpiece holder, as shown in FIGS. 7 and 8. Since the workpiece holder  478  may be removed as described above, it is possible to replace one style of workpiece holder with another. Since a variety of workpiece holders with a variety of fingers for holding the workpiece is possible, it is desirable to have a finger actuator mechanism disposed within processing head  407  which is compatible with any given finger arrangement. The invention is therefore advantageously provided with a finger actuator mechanism. 
     Turning to FIG. 7, a finger actuator mechanism  500  is shown. Finger actuator mechanism  500  is preferably a pneumatically operated mechanism. A pneumatic cylinder is formed by a cavity  501  within top motor housing  481 . Pneumatic piston  502  is disposed within cavity  501 . Pneumatic piston  502  is biased in an upward position within cavity  501  by actuator spring  505 . Actuator spring  505  is confined within cavity  501  by cavity end cap  507 , which is itself constrained by retaining ring  508 . Pneumatic fluid is provided to the top of pneumatic piston  502  via pneumatic inlet  503 . Pneumatic fluid is provided to pneumatic inlet  503  by pneumatic supply line  504  which is routed through processing head pivot shaft  429  and hence through the left fork  418  of the operator arm  407 . Turning to FIG. 8, it can be seen that a second pneumatic cylinder which is identical to the pneumatic cylinder just described is also provided. 
     Pneumatic piston  502  is attached to actuator plate  509  by actuator plate connect screw  510 . Wave springs  529  provide flexibility to the connecting at screws  510 . Actuator plate  509  is preferably an annular plate concentric with the spin motor  580  and disposed about the bottom motor housing  482 , and is symmetrical about spin axis  479 . Actuator plate  509  is secured against pneumatic piston  502  by bushing  512  which is disposed in pneumatic piston recess  511  about pneumatic piston  502 . Bushing  512  acts as a support for wave springs  529  to allow a slight tilting of the actuator plate  509 . Such an arrangement is beneficial for providing equal action against the finger actuator contracts  513  about the entire actuator plate or ring  509 . 
     When pneumatic fluid is provided to the space above the pneumatic piston  502 , the pneumatic piston  502  travels in a downward direction compressing actuator spring  505 . As pneumatic piston  502  travels downward, actuator plate  509  is likewise pushed downward by flexible bushing  512 . Actuator plate  509  will contact finger, actuator contacts  513  causing the fingers to operate as more fully described below. 
     Actuator seals  506  are provided to prevent pneumatic gas from bypassing the top of the pneumatic piston  502  and entering the area occupied by actuator spring  505 . 
     Processing Head Workpiece Holder 
     Workpiece holder  478  is used to hold the workpiece W, which is typically a semiconductor wafer, in position during the semiconductor manufacturing process. 
     Turning now to FIG. 8, a finger  409  is shown in cross section. Finger  409  advantageously includes a finger actuator contact  513  which is contacted by actuator plate  509 , as described above. Finger actuator contact  513  is connected to finger actuator lever  514  (more generally, “finger extension”) which is cantilevered from and connected to the finger stem  515 . Finger stem  515  is inserted into finger actuator lever  514 . Disposed about the portion of the finger actuator lever which encompasses and secures finger stem  515  is finger diaphragm  519 . Finger diaphragm  519  is preferably made of a flexible material such &lt;as Tetrafluoroethylene, also known as Teflon® (registered trademark of E. I. DuPont de Nemours Company). Finger  409  is mounted to workpiece holder rotor  484  using finger diaphragm  519 . Finger diaphragm  519  is inserted into the finger opening  521  in rotor  484 . The finger diaphragm  519  is inserted into the rotor from the side opposite that to which the workpiece will be presented. Finger diaphragm  519  is secured to rotor  484  against rotor diaphragm lip  523 . Forces are intentionally imparted as a result of contact between the actuator plate  509  and the finger actuator contact  513  when the finger actuator mechanism  500  is actuated. 
     Finger actuator lever  514  is advantageously biased in a horizontal position by finger spring  520  which acts on finger actuator tab  522  which in turn is connected to finger actuator lever  514 . Finger spring  520  is preferably a torsion spring secured to the workpiece holder rotor  484 . 
     Finger stem  515  is also preferably provided with finger collar or nut  517  which holds the finger stem  515  against shoulder  518 . Finger collar  517  threads or otherwise securely fits over the lower end of finger actuator lever  514 . Below the finger collar  517 , finger stem  515  extends for a short distance and terminates in fingertip  414 . Fingertip  414  contains a slight groove or notch which is beneficially shaped to receive the edge of the workpiece W. 
     In actuation, finger actuator plate  509  is pushed downward by finger actuator mechanism  500 . Finger actuator plate  509  continues its downward travel contacting finger actuator contacts  513 . As actuator plate  509  continues its downward travel, finger actuator contacts are pushed in a downward direction. As a result of the downward direction, the finger actuator levers  514  are caused to pivot. 
     In the preferred embodiment, a plurality of fingers are used to hold the workpiece. In one example, six fingers were used. Once the actuator plate  509  has traveled its full extent, the finger stems  515  will be tilted away from the spin axis  479 . The circumference described by the fingertips in this spread-apart position should be greater than the circumference of the workpiece W. Once a workpiece W has been positioned proximate to the fingertips, the pneumatic pressure is relieved on the finger actuator and the actuator spring  505  causes the pneumatic piston  502  to return to the top of the cavity  501 . In so doing, the actuator plate  509  is retracted and the finger actuator levers are returned to their initial position by virtue of finger springs  520 . 
     Semiconductor Workpiece Holder—Electroplating Embodiment 
     FIG. 15 is a side elevational view of a semiconductor workpiece holder  810  constructed according to a preferred aspect of the invention. 
     Workpiece holder  810  is used for processing a semiconductor workpiece such as a semiconductor wafer shown in phantom at W. One preferred type of processing undertaken with workpiece holder  810  is a workpiece electroplating process in which a semiconductor workpiece is held by workpiece holder  810  and an electrical potential is applied to the workpiece to enable plating material to be plated thereon. Such can be, and preferably is accomplished utilizing a processing enclosure or chamber which includes a bottom half or bowl  811  shown in phantom lines in FIG.  1 . Bottom half  811  together with workpiece holder  810  forms a sealed, protected chamber for semiconductor workpiece processing. Accordingly, preferred reactants can be introduced into the chamber for further processing. Another preferred aspect of workpiece holder  810  is that such moves, rotates or otherwise spins the held workpiece during processing as will be described in more detail below. 
     Processing Head and Processing Head Operator 
     Turning now to FIG. 15, semiconductor workpiece holder  810  includes a workpiece support  812 . Workpiece support  812  advantageously supports a workpiece during processing. Workpiece support  812  includes a processing head or spin head assembly  814 . Workpiece support  812  also includes a head operator or lift/rotate assembly  816 . Spin head assembly  814  is operatively coupled with lift/rotate assembly  816 . Spin head assembly  814  advantageously enables a held workpiece to be spun or moved about a defined axis during processing. Such enhances conformal coverage of the preferred plating material over the held workpiece. Lift/rotate assembly  816  advantageously lifts spin head assembly  814  out of engagement with the bottom half  811  of the enclosure in which the preferred processing takes place. Such lifting is preferably about an axis x 1 . Once so lifted, lift/rotate assembly  816  also rotates the spin head and held workpiece about an axis x 2  so that the workpiece can be presented face-up and easily removed from workpiece support  812 . In the illustrated and preferred embodiment, such rotation is about 180° from the disposition shown in FIG.  15 . Advantageously, a new workpiece can be fixed or otherwise attached to the workpiece holder for further processing as described in detail below. 
     The workpiece can be removed from or fixed to workpiece holder  810  automatically by means of a robotically controlled arm. Alternatively, the workpiece can be manually removed from or fixed to workpiece holder  810 . Additionally, more than one workpiece holder can be provided to support processing of multiple semiconductor workpieces. Other means of removing and fixing a semiconductor workpiece are possible. 
     FIG. 16 is a front sectional view of the FIG. 15 semiconductor workpiece holder. As shown, workpiece support  812  includes a motor  818  which is operatively coupled with a rotor  820 . Rotor  820  is advantageously mounted for rotation about a rotor spin axis  822  and serves as a staging platform upon which at least one finger assembly  824  is mounted. Preferably, more than one finger assembly is mounted on rotor  820 , and even more preferably, four or more such finger assemblies are mounted thereon and described in detail below although only two are shown in FIG.  16 . The preferred finger, assemblies are instrumental in fixing or otherwise holding a semiconductor workpiece on semiconductor workpiece holder  810 . Each finger assembly is advantageously operatively connected or associated with a actuator  825 . The actuator is preferably a pneumatic linkage which serves to assist in moving the finger assemblies between a disengaged position, in which a workpiece may be removed from or added to the workpiece holding, and an engaged position in which the workpiece is fixed upon the workpiece holder for processing. Such is described in more detail below. 
     FIG. 17 is a top or plan view of rotor  820  which is effectively taken along line  3 — 3  in FIG.  16 . FIG. 16 shows the preferred four finger assemblies  824 . As shown, rotor  820  is generally circular and resembles from the top a spoked wheel with a nearly continuous bottom surface. Rotor  820  includes a rotor center piece  826  at the center of which lies rotor axis  822 . A plurality of struts or spokes  828  are joined or connected to rotor center  826  and extend outwardly to join with and support a rotor perimeter piece  830 . Advantageously, four, of spokes  828  support respective preferred finger assemblies  824 . Finger assemblies  824  are advantageously positioned to engage a semiconductor workpiece, such as a wafer W which is shown in phantom lines in the position such would occupy during processing. When a workpiece is so engaged, it is fixedly held in place relative to the rotor so that processing can be effected. Such processing can include exposing the workpiece to processing conditions which are effective to form a layer of material on one or more surfaces or potions of a wafer or other workpiece. Such processing can also include moving the workpiece within a processing environment to enhance or improve conformal coverage of a layering material. Such processing can, and preferably does include exposing the workpiece to processing conditions which are effective to form an electroplated layer on or over the workpiece. 
     Finger Assembly 
     Referring now to FIGS. 18-20, various views of a preferred finger assembly are shown. The preferred individual finger assemblies are constructed in accordance with the description below FIG. 18 is an isolated side sectional view of a finger assembly constructed in accordance with a preferred aspect of the invention. FIG. 19 is a side elevational view of the finger assembly turned 90° from the view of FIG.  18 . FIG. 20 is a fragmentary cross-sectional enlarged view of a finger assembly and associated rotor structure. The finger assembly as set forth in FIGS. 18 and 19 is shown in the relative position such as it would occupy when processing head or spin head assembly  814  (FIGS. 15 and 16) is moved or rotated by head operator or lift/rotate assembly  816  into a position for receiving a semiconductor workpiece. The finger assembly is shown in FIGS. 18 and 20 in an orientation of about 180° from the position shown in FIG.  20 . This typically varies because spin head assembly  814  is rotated 180° from the position shown in° FIGS. 15 and 16 in order to receive a semiconductor workpiece. Accordingly, finger assemblies  824  would be so rotated. Lesser degrees of rotation are possible. 
     Finger assembly  824  includes a finger assembly frame  832 . Preferably, finger assembly frame  832  is provided in the form of a sealed contact sleeve which includes an angled slot  832   a , only a portion of which is shown in FIG.  19 . Angled slot  832   a  advantageously enables the finger assembly to be moved, preferably pneumatically, both longitudinally and rotationally as will be explained below. Such preferred movement enables a semiconductor workpiece to be engaged, electrically contacted, and processed in accordance with the invention. 
     Finger assembly frame  832  includes a finger assembly frame outer flange  834  which, as shown in FIG. 20, engages an inner drive plate portion  836  of rotor  820 . Such engagement advantageously fixes or seats finger assembly frame  832  relative to rotor  820 . Such, in turn, enables the finger assembly, or a portion thereof, to be moved relative to the rotor for engaging the semiconductor workpiece. 
     Finger Assembly Drive System 
     Referring to FIGS.  16  and  18 - 20 , the finger assembly includes a finger assembly drive system which is utilized to move the finger assembly between engaged and disengaged positions. The finger assembly drive system includes a bearing  838  and a collet  840  operatively adjacent the bearing. Bearing  838  includes a bearing receptacle  839  for receiving a pneumatically driven source, a fragmented portion of which is shown directly above the receptacle in FIG.  20 . The pneumatically driven source serves to longitudinally reciprocate and rotate collet  840 , and hence a preferred portion of finger assembly  824 . A preferred pneumatically driven source is described below in more detail in connection with the preferred longitudinal and rotational movement effectuated thereby. Such longitudinal reciprocation is affected by a biasing mechanism in the form of a spring  842  which is operatively mounted between finger assembly frame  832  and, a spring seat  844 . The construction develop a bias between finger assembly frame  832  and spring seat  844  to bias the finger into engagement against a wafer. Advantageously, the cooperation between the above mentioned pneumatically driven source as affected by the biasing mechanism of the finger assembly drive system, enable collet  840  to be longitudinally reciprocated in both extending and retracting modes of movement. As such, finger assembly  824  includes a biased portion which is biased toward a first position and which is movable to a second position away from the first position. Other manners of longitudinally reciprocating the finger assembly are possible. 
     Finger Assembly Electrical System 
     Referring to FIGS. 16 and 19, the finger assembly preferably includes a finger assembly electrical system which is utilized to effectuate an electrical bias to a held workpiece and supply electrical current relative thereto. The finger assembly electrical system includes a pin connector  846  and a finger  848 . Pin connect or  846  advantageously provides an electrical connection to a power source (not shown) via wire  585  and associate slip ring mechanism, described above in connection with FIG.  7  and other FIGS. This is for delivering an electrical bias and current to an electrode which is described below. Pin connector  846  al so rides within angled slot  832   a  thereby mechanically defining the limits to which the finger assembly may be both longitudinally and rotationally moved. 
     Finger  848  is advantageously fixed or secured to or within collet  840  by a nut  850  which threadably engages a distal end portion of collet  840  as shown best in FIG.  18 . An anti-rotation pin  852  advantageously secures finger  848  within collet  840  and prevents relative rotation therebetween. Electrical current is conducted from connector  846  through collet  840  to finger  860 , all of which are conductive, such as from stainless steel. The finger and collet can be coated with a suitable dielectric coating  856 , such as TEFLON or others. The collet  840  and finger member  860  are in one form of the invention made hollow and tubular to conduct a purge gas therethrough. 
     Finger assembly  824  may also optionally include a distal tip or finger tip  854 . Tip  854  may also have a purge gas passage formed therethrough. Finger tip  854  advantageously engages against, a semiconductor workpiece (see FIG. 20) and assists in holding or fixing the position of the workpiece relative to workpiece holder  810 . Finger tip  854  also assists in providing an operative electrical connection between the finger assembly and a workpiece to which an electrical biased is to be applied and through which current can move. Finger tip  85  can include an electrode contact  858  for electrically contacting a surface of a semiconductor workpiece once such workpiece is secured as describe below. 
     Finger Assembly Drive System Interface 
     A finger assembly drive system interface is operatively coupled with the finger assembly drive system to effectuate movement of the finger assembly between the engaged and disengaged positions. A preferred finger assembly drive system interface is described with reference to FIGS. 16 and 20. One component of the finger assembly drive system interface is a finger actuator  862 . Fingers actuator  862  is advantageously provided for moving the finger assembly between the engaged and disengaged position. Finger actuator  862  acts by engaging bearing receptacle  839  and moving finger assembly  824  between an engaged position and a disengaged position. In the engaged position, finger tip  854  is engaged against a semiconductor workpiece. In the disengaged position finger tip  854  is moved away from the workpiece. 
     The finger assembly drive system interface includes pneumatic actuator  825  (FIG.  16 ). Pneumatic actuators  825  are operatively connected to an actuation ring  863  and operates thereupon causing the drive plate to move reciprocally in the vertical direction as viewed in FIG.  16 . Finger actuator  862  is operatively connected to actuation ring  863  in a manner which, upon pneumatic actuation, moves the finger actuator into engagement with bearing receptacle  839  along the dashed line in FIG.  20 . Such allows or enables the finger assembly to be moved longitudinally along a first movement path axis  864 . 
     Pneumatic actuator linkage  825  also includes a secondary linkage  865 . Secondary linkage  865  is pneumatic as well and includes a link arm  867 . Link arm  867  is connected or joined to an actuator torque ring  869 . Preferably, torque ring  869  is concentric with rotor  820  (FIG. 17) and circuitously links each of the finger actuators together. A pneumatic operator  871  is advantageously linked with the secondary linkage  865  for applying force and operating the linkage by angularly displacing torque ring  869 . This in turn rotates the finger assemblies into and away from the engaged position. 
     Preferably finger actuator engagement bits  862 , under the influence of pneumatic linkage  825 , moves the finger assembly, and more specifically collet  840  and finger  848  along a first axial movement path along axis  864 . The finger actuator engagement bits  862 , then under the influence of pneumatic operator  871  are turned about the axes of each bit like a screwdriver. This moves collet  840  and finger  848  in a second angular movement. Such second movement turns the fingers sufficiently to produce the angular displacement shown in FIG.  21 . According to a preferred aspect of this invention, such movement of the finger assemblies between the engaged and disengaged positions takes place when spin head assembly  814  has been moved 180° from its FIG. 15 disposition into a face-up condition. 
     The engagement bits  862  can be provided with a purge gas passage therethrough. Gas is supplied via tube  893  and is passed through the finger assemblies. 
     Engaged and Disengaged Positions 
     FIG. 21 is a view of a portion of a finger assembly, taken along line  7 — 7  in FIG.  18 . Such shows in more detail the above-described engaged and disengaged positions and movement therebetween relative to a workpiece W In the disengaged position, finger  848  is positioned adjacent the semiconductor workpiece and the finger tip and electrode contact do not overlap with workpiece W. In the engaged position, the finger tip overlaps with the workpiece and the electrode is brought to bear against the workpiece. From the disengaged position, finger assembly  824 , upon the preferred actuation, is moved in a first direction away from the disengaged position. Preferably, such first direction is longitudinal and along first movement path axis  864 . Such longitudinal movement is linear and in the direction of arrow A as shown in FIGS. 18 and 19. The movement moves the finger assembly to the position shown in dashed lines in FIG.  18 . Such movement is effectuated by pneumatic operator  825  which operates upon actuation ring  863  (FIG.  16 ). This in turn, causes finger actuator  862  to engage with finger assembly  824 . Such linear movement is limited by angled slot  832   a . Thereafter, the finger assembly is preferably moved in a second direction which is different from the first direction and preferably rotational about the first movement path axis  864 . Such is illustrated in FIG. 21 where the second direction defines a generally actuate path between the engaged and disengaged positions. Such rotational movement is effectuated by secondary linkage  865  which pneumatically engages the finger actuator to effect rotation thereof. As so moved, the finger assembly swings into a ready position in which a semiconductor workpiece is ready to be engaged and held for processing. Once the finger assembly is moved or swung into place overlapping a workpiece, the preferred finger actuator is spring biased and released to bear against the workpiece. An engaged workpiece is shown in FIG. 20 after the workpiece has been engaged by finger tip  854  against a workpiece standoff  865 , and spin head assembly  814  has been rotated back into the position shown in FIG.  15 . Such preferred pneumatically assisted engagement takes place preferably along movement path axis  864  and in a direction which is into the plane of the page upon which FIG. 21 appears. 
     As shown in FIG. 18, finger  848  extends away from collet  840  and preferably includes a bend  866  between collet  840  and finger tip  854 . The preferred bend is a reverse bend of around  1800  which serves to point finger tip  854  toward workpiece W when the finger assembly is moved toward or into the engaged position (FIG.  21 ). Advantageously, the collet  840  and hence finger  848  are longitudinally reciprocally movable into and out of the engaged position. 
     Finger Assembly Seal 
     The finger assembly preferably includes a finger assembly seal  868  which is effectuated between finger  848  and a desired workpiece when the finger assembly is moved into the engaged position. Preferably, adjacent finger tip  854 . A seal  868  is mounted adjacent electrode contact  858  and effectively seals the electrode contact therewithin when finger assembly  824  is moved to engage a workpiece. The seal can be made of a suitable flexible, preferably elastomeric material, such as VITON. 
     More specifically, and referring to FIG. 22, seal  868  can include a rim portion  870  which engages workpiece surface W and forms a sealing contact therebetween when the finger assembly is moved to the engaged position. Such seal advantageously isolates finger electrode  860  from the processing environment and materials which may plate out or otherwise be encountered therein. Seal  868  can be provided with an optional bellows wall structure  894  (FIG.  22 ), that allows more axial flexibility of the seal. 
     FIG. 22 shows, in solid lines, seal  868  in a disengaged position in which rim portion  870  is not engaged with workpiece W. FIG. 22 also shows, in phantom lines, an engaged position in which rim portion  870  is engaged with and forms a seal relative to workpiece W. Preferably and advantageously, electrode contact  858  is maintained in a generally retracted position within seal  868  when the finger assembly is in the disengaged position. However, when the finger assembly is moved into the engaged position, seal  868  and rim portion  870  thereof splay outwardly or otherwise yieldably deform to effectively enable the electrode and hence electrode contact  858  to move into the engaged position against the workpiece. One factor which assists in forming the preferred seal between the rim portion and the workpiece is the force which is developed by spring  842  which advantageously urges collet  840  and hence finger  860  and finger tip  858  in the direction of and against the captured workpiece. Such developed force assists in maintaining the integrity of the seal which is developed in the engaged position. Another factor which assists in forming the preferred seal is the yieldability or deformability of the finger tip when it is brought into contact with the workpiece. Such factors effectively create a continuous seal about the periphery of electrode contact  858  thereby protecting it from any materials, such as the preferred plating materials which are used during electroplate processing. 
     Methods and Operation 
     In accordance with a preferred processing aspect of the present invention, and in connection with the above-described semiconductor workpiece holder, a sheathed electrode, such as electrode  860 , is positioned against a semiconductor workpiece surface in a manner which permits the electrode to impart a voltage bias and current flow to the workpiece to effectuate preferred electroplating processing of the workpiece. Such positioning not only allows a desired electrical bias to be imparted to a held workpiece, but also allows the workpiece itself to be mechanically held or fixed relative to the workpiece holder. That is, finger assembly  824  provides an electrical/mechanical connection between a workpiece and the workpiece holder as is discussed in more detail below. 
     Electrode  856  includes an electrode tip or electrode contact  858  which engages the workpiece surface. A seal is thus formed about the periphery of the electrode tip or contact  858  so that a desired electrical bias may be imparted to the workpiece to enable plating material to be plated thereon. According to a preferred aspect of the processing method, the electrode is moved in a first direction, preferably longitudinally along a movement axis, away from a disengaged position in which the workpiece surface is not engaged by the electrode tip or contact  858 . Subsequently, the electrode is rotated about the same movement axis and toward an engaged position in which the electrode tip may engage, so as to fix, and thereafter bias the workpiece surface. 
     Such preferred movement is effectuated by pneumatic linkage  825  and pneumatic operator  871  as described above. 
     According to a preferred aspect of the invention, the seal which is effectuated between the electrode member and the workpiece is formed by utilizing a yieldable, deformable seal member  868  which includes a rim portion  870 . The rim portion  870  serves by contacting the workpiece surface to form a continuous seal as shown in FIG.  8 . The preferred electrode tip is brought into engagement with the workpiece surface by advancing the electrode tip from a retracted position within the seal or other sheath to an unretracted position in which the workpiece surface is engaged thereby. Such movement of the electrode tip between the retracted and unretracted positions is advantageously accommodated by the yieldable features of the seal  868 . 
     In addition to providing the preferred electrical contact between the workpiece and the electrode tip, the finger assembly also forms a mechanical contact or connection between the assembly and the workpiece which effectively fixes the workpiece relative to the workpiece holder. Such is advantageous because one aspect of the preferred processing method includes rotating the workpiece about rotor axis  822  while the workpiece is exposed to the preferred plating material. Such not only ensures that the electrical connection and hence the electrical bias relative to the workpiece is maintained during processing, but that the mechanical fixation of the workpiece on the workpiece holder is maintained as well. 
     The above described pneumatically effectuated movement of the preferred finger assemblies between the engaged and disengaged positions is but one manner of effectuating such movement. Other manners of effectuating such movement are possible. 
     The invention also includes novel methods for presenting a workpiece to a semiconductor process. In such methods, a workpiece is first secured to a workpiece holder. The methods work equally well for workpiece holders known in the art and for the novel workpiece holders disclosed herein. 
     In the next step in the sequence, the workpiece holder is rotated about a horizontal axis from an initial or first position where the workpiece holder was provided with the workpiece to a second position. The second position will be at an angle to the horizontal. The angle of the workpiece holder to the horizontal is defined by the angle between the plane of the workpiece and the horizontal. In the method, the workpiece holder is advantageously suspended about a second horizontal axis which is parallel to the first horizontal axis of the workpiece holder. At this point in the method, the angle between the first and second horizontal axes and a horizontal plane corresponds to the angle between the workpiece holder and the horizontal. The workpiece holder is then pivoted about the second horizontal axis to move the workpiece and the workpiece holder from its initial location to a final location in a horizontal plane. Advantageously, when the workpiece holder is pivoted about the second horizontal axis, the first horizontal axis also pivots about the second horizontal axis. 
     Preferably, during the step of rotating the workpiece holder about the first horizontal axis, the angle of the workpiece holder with respect to some known point, which is fixed with respect to the workpiece holder during the rotation process, is continually monitored. Monitoring allows for precise positioning of the workpiece holder with respect to the horizontal surface. 
     Likewise, during pivoting of the workpiece holder about the second horizontal axis, it is preferable that the angle defined by the line connecting the first and second horizontal axes and the horizontal plane be continually monitored. In this manner, the absolute position of the workpiece holder (and hence the workpiece itself) will be known with respect to the horizontal plane. This is important since the horizontal plane typically will contain the process to which the workpiece will be exposed. 
     It should be noted that in the above and following description, while the workpiece is described as being presented to a horizontal plane, it is possible that the workpiece may also be presented to a vertical plane or a plane at any angle between the vertical and the horizontal. Typically, the processing plane will be a horizontal plane due to the desire to avoid gravitational effects on process fluids to which the workpiece is exposed. In one embodiment after the workpiece has been presented to the processing plane, the workpiece holder is rotated about a spin axis to cause the workpiece to spin in the horizontal plane. Although not required in all semiconductor manufacturing processes, this is a common step which may be added in the appropriate circumstance. 
     The next advantageous step in the method consists of pivoting the workpiece holder about the second horizontal axis back along the path that the workpiece holder was initially pivoted along when presenting the workpiece to the horizontal process plane. There is no requirement that the workpiece holder be pivoted back to the same position whence it began, although doing so may have certain advantages as more fully described below. 
     The method advantageously further consists of the step of rotating the workpiece holder about the first horizontal axis to return the workpiece to the position when it was initially presented to and engaged by the workpiece holder. It is advantageous to rotate the workpiece holder about the first axis in a direction opposite from the initial rotation of the workpiece holder. 
     The advantage of having the workpiece holder terminate at an end position which corresponds to the initial position when the workpiece was loaded into the workpiece holder is efficiency. That is, additional machine movements are not required to position the workpiece holder to receive a new workpiece. 
     The method more preferably includes the step of rotating the workpiece holder about the first horizontal axis at least two support points along the first horizontal axis. This beneficially provides support and stability to the workpiece holder during the rotation process and subsequent movement of the apparatus. 
     The method also more preferably includes the step of pivoting the workpiece holder along with the first horizontal axis about the second horizontal axis at least two support points along the second horizontal axis. This beneficially provides additional support for the workpiece holder while allowing the workpiece holder to be moved in a vertical “Z-axis” direction. 
     Importantly, the only motion described in the above method is rotational motion about several axes. In the method described, there is no translational motion of the workpiece holder in a X-, Y-, or Z-axis without corresponding movement in another axisz as a result of rotating through an arc. 
     Second Embodiment Processing Station—Generally 
     FIG. 23 shows principal components of a second semiconductor processing station  900  incorporating features of the invention. Processing station  900  as shown is specifically adapted and constructed to serve as an electroplating station similar to electroplating station  400  described hereinabove. To reduce unnecessary replication, only the principal parts showing differences and features of the invention are shown and described. Other aspects of the invention are as described above or can be done in a variety of constructions. 
     The two principal parts of processing station  900  are the workpiece support assembly  901  and the processing bowl  917 . The workpiece support  401  will be considered first and the processing bowl and its features will be described in further detail later in this description. As FIG. 23 indicates, portions of the workpiece support  401  mate with the processing bowl to provide a substantially closed processing vessel which encloses a substantially enclosed processing or manufacturing chamber  904 . 
     Workpiece Support Generally 
     The workpiece support processing head holds a wafer W for rotation within the processing chamber  904 . A rotor assembly  984  has a plurality of workpiece-engaging fingers  979  that hold the wafer against features of the rotor. Fingers  979  are also preferably adapted to conduct current between the wafer and a plating electrical power supply (not shown). 
     Workpiece Support Head Operator 
     The workpiece support assembly  901  includes a processing head  906  which is supported by an head operator  907 . Head operator  907  includes an upper portion  908  which is adjustable in elevation to allow height adjustment of the processing head. Head operator  907  also has a head connection shaft  909  which is operable to pivot about a horizontal pivot axis  910 . Pivotal action of the processing head using operator  907  allows the processing head to be placed in an open or face-up position (not shown) for loading and unloading wafer W. FIG. 23 shows the processing head pivoted into a face-down position in preparation for processing. 
     A variety of suitable head operators which provide both elevational and horizontal pivoting action are possible for use in this system. The preferred operators are also fitted with positional encoders (not shown) which indicate both the elevation of the processing head and its angular position as pivoted about horizontal head pivot axis  910 . 
     Workpiece Support Main Part 
     FIGS. 24 and 25 show additional details of the preferred construction of processing head  906 . The processing head includes a main part which moves with and is relatively stationary with respect to the pivot shaft  909 . The main part supports a rotating assembly which will be described in greater detail below. 
     The main part includes a processing head housing  970  and processing head frame  982 . The processing head frame  982  includes a door plate  983 . A door ring member  984  is joined to plate  983  using suitable fasteners to provide a door assembly which serve as the principal parts covering the upper opening of the processing bowl when the processing head is mated with the bowl. 
     The processing head frame also includes a frame-pivot shaft connection  985  which includes two mounting rings which receive and securely connect with the processing head pivot shaft  909 . FIG. 25 shows that the pivot shaft connection mounting rings are made in two parts and secured by fasteners (not shown). The pivot shaft connection base  935  is secured to the door plate  983  using fasteners. 
     Processing head  906  is generally round in shape when viewed in plan view. The processing head main part includes a housing  970  which has a first housing part  971  and a second housing part or housing cap  972 . The processing head housing  970  encloses a main part enclosure which surrounds a processing head main part mechanism chamber  973 . Chamber  973  is used to house additional processing head components, such as the spin motor, the finger actuators, and related service lines, such as discussed more fully below. 
     The upper surface of the door ring member  984  is provided with a groove which receives the lower edge of the first housing piece  971 . The outer periphery of the door ring member also advantageously includes a peripheral groove  986  which mounts an inflatable door seal  987 . Seal  987  seals with portions of the processing bowl to form a more fluid-tight processing chamber therewithin. 
     The lower surface of the door ring member  984  is preferably provided with an annular rotor receiving groove  988  which receives top peripheral portions of the rotor therein in close proximity. This construction allows a gas purge (not shown) to be applied between the door and rotor to help prevent processing vapors from migrating behind the rotor and into to the various mechanisms present in the main part of the processing head. The periphery of the door ring member is further provided with a chamfered lower edge to facilitate mating with the processing bowl. 
     The processing head also advantageously includes a moving assembly in the form of a workpiece holder  978 . The workpiece holder includes fingers  979  for holding a semiconductor workpiece. These features will be more fully described below. 
     Workpiece Support Rotor Drive 
     The processing head main part also includes a workpiece holder drive which moves the workpiece holder relative to the main part of the processing head. The preferred action is for the workpiece holder drive to be in the form of a rotor drive which rotates the workpiece holder. The rotor drive can be an electric motor, pneumatic motor or other suitable drive. As shown, the processing head includes an electric workpiece spin motor  980 . 
     The drive motor  980  has stator armatures  916  which drive motor shaft  918  in rotational movement. Drive motor  980  is supported by bottom motor bearing  921  in bottom motor housing  922 . Bottom motor housing  922  is secured to the main part of the processing head at a central opening in the door plate  983 . Motor  980  is also held in place by a top motor housing  923 . Drive motor  980  is rotationally isolated from top motor housing  923  by a top motor bearing  927 , which is disposed between the spin motor shaft  918  and the top motor housing. Both motor housings are secured to the processing head frame  982  using fasteners  924  which extend down through the motor housings and into the door plate  983 . The fasteners  924  also extend upwardly through frame extensions  925 . Frame extensions  925  support a top frame piece  926 . Cap  972  is screwed onto piece  926  at mating threads along the lower interior portion of the cap. 
     The drive motor is preferably an electric motor provided with a supply of electricity via wiring run through pivot shaft  909  or otherwise extending to the processing head. 
     Workpiece Support Rotor Assembly 
     The hollow shaft  918  of the drive motor receives portion of a rotor assembly therein. The rotor assembly is secured to the motor shaft and is rotated therewith. FIG. 26 shows major portions of the rotor assembly in exploded detail. The rotor assembly  930  includes a rotor shaft  931 . Rotor shaft  931  has a rotor shaft hub  932  which is held within a shaft hub receptacle  933  formed in an inner rotor part  934 . The inner or first rotor part  934 , also called an inner rotor drive plate, has a plurality of spokes which extend from the inner rotor part hub  935  outwardly to connect with a peripheral band  936 . The shaft hub,  932  is held in the hub receptacle  933  using a snap-ring  937 . 
     The inner rotor part  934  also includes a plurality of receptacles  937 . Receptacles  937  are used to mount a plurality of actuator transmission assemblies  960 . The transmission receptacles  937  receive lower portions of the transmission assemblies. The receptacles have bottom openings through which the finger assemblies  979  (see. FIG. 24) extend and are mounted in the transmission assemblies. Additional description is provided below in connection with the finger assembly actuators. 
     FIG. 26 also shows that the rotor assembly  930  preferably includes a second or outer rotor part  940 . The inner and outer rotor parts are secured together by fasteners  941  (see FIG.  24 ). The outer rotor part  940  includes a rotor face panel  943  which extends across the disk-shaped rotor part to form a barrier to processing fluids. 
     The front or exposed side of the outer rotor part is provided with apertures  787  through which finger actuator transmission shafts  963  extend in supporting relationship for the fingers  979 . Workpiece support standoffs  721  are mounted upon the face of the rotor to support the back side of the workpieces in opposition to the forces exerted by the fingers  979 . The face of the rotor can also advantageously be provided with workpiece peripheral guide pins  722  to facilitate proper location of a wafer upon installation upon the face of the rotor. 
     Along the back side of the outer rotor part are reinforcing ribs  942  which align with the spokes of the inner rotor part  934 . The reinforcing ribs  942  receive fasteners  941  and connect the two rotor parts together. At the periphery of the outer rotor part is a side wall  944 . The upper or back edge of the peripheral side wall  944  is in close fitting relationship with the door ring  984  at annular groove  988  to resist migration of processing fluids to the back side of the rotor assembly. 
     The outer rotor part  940  also has an array of bosses  948  at the peripheral end of the reinforcing ribs  942 . Within bosses  948  are finger passageways  949  which allow the finger assemblies  979  to mount in the finger actuator transmission assemblies  960 . The rotor assembly also includes the transmission assemblies and finger assemblies. Additional details of these components as well as additional parts of the finger actuation mechanisms is described in greater detail below. 
     The rotor shaft  931  fits inside of motor shaft  918  and protrudes from the top of the shaft and is held by a rotor shaft mounting nut  888 . Also mounted near the top of the rotor shaft is an optical tachometer  499 . Optical tachometer  499  is securely attached to motor shaft  918  and features, such as notches, formed on the tachometer are optically detected to provide a precise measurement of rotor angular velocity. The optical emitter-detector couplet used with tachometer  499  are not shown, but are mounted on either sides of the wheel to allow selective passage of light therethrough. 
     The rotor assembly is also advantageously provided with a angular position encoder  498 . As shown, encoder  498  is mounted to the top motor housing  923  so as to remain stationary with respect to the main part of the processing head. The angular position encoder  498  and optical tachometer  499  allow the speed, acceleration, and precise rotational position of the motor shaft  918  and rotor assembly to be known and controlled. 
     In one application of the present invention the workpiece support is used to support a semiconductor workpiece in an electroplating process. To accomplish the electroplating an electric current is provided to the workpiece through an alternate embodiment of the fingers (described more fully below). To provide electric current to the electrode fingers  979 , conductive wires (not shown) are run from the transmissions  960  toward the hub of the rotor. Current is supplied to the electrode fingers  979  through the hollow rotor shaft using wires (not shown) connected to a slip ring electrical connector  687  mounted near the upper end of shafts  918  and  931 . 
     Workpiece Detection Subsystem 
     The processing head also preferably includes a wafer or workpiece detection subsystem. This subsystem allows the processing head to through its control system to determine whether there is a workpiece held in the rotor or not. This is of particular significance if the system experiences a power interruption or otherwise is being started in any situation where workpieces may be present in the machine. Operational safeguards can then be included in the control system to prevent mishandling of wafers or processing stations which may have a workpiece held therein. 
     As shown in FIG. 25, the processing head frame part  983  is provided with a mounting  738  which is an appropriately shaped recess used to mount a detector  739 . Detector  739  is preferably an optical emitter-detector unit which emits a beam which passes downwardly as oriented in FIG.  25 . The emitted beam passes through workpiece detector windows  741  (see FIG. 26) formed in the face panel of the outer rotor part. The windows can be discrete inserts, or more preferably, they are thinly dimensioned panel portions of the rotor face panel  943 . The rotor face panel is advantageously made of a material which is transmissive of the detector beam being used. For example, the panel can be made from polyvinylidene fluoride polymer which is thinned to a suitably thin dimension, such as in the approximate range from about 1-5 millimeters. 
     A suitable detector  739  is a Sunx brand model RX-LS200, and other commercially available detectors. The preferred detector uses an infrared beam emitter (not individually shown) which is detected by a pair of beam detectors (not individually shown). The beam emitter and beam detectors are preferably part of the same unit which serves as the workpiece detector. The workpiece detector preferably operated in a trigonometric mode. In the trigonometric mode, the angle of the reflected beam is an important discriminating parameter. Thus any portion of the beam reflected by the detector window  741  is incident upon the pair of detectors at a reflection angle which is outside of the normal detection angel range. Such portions of the beam reflected by the window  741  are thus minimized and the detector is not triggered by such reflectance. Instead, the pair of beam detectors are adjusted to sense a reflected beam which is incident at a reflected angle associated with the wafer or other workpiece surface which is more distant than the window. When there is no workpiece held in the workpiece holder, then the detector senses the absence and this is used by the control system as an indication that there is no wafer present in the wafer support. 
     In general the emitted infrared beam used in the preferred workpiece detector subsystem is sufficient to detect the presence of a wafer or other semiconductor workpiece held in a stationary position with the rotor positioned so that one of the windows  741  is in position aligned to allow the emitted beam to pass therethrough and be reflected by the workpiece back through the window for detection. The detection system described herein is not sufficient to allow detection during rotation of the rotor and any workpiece held thereon. The invention may also be practiced in a situation where sensing can be accomplished while the rotor rotates. 
     The workpiece detector arrangement shown has the distinct benefit of being mounted wholly behind the rotor face panel without provision of any openings which might allow processing fluids to enter the space behind the rotor. This reduces maintenance, improves reliability, and simplifies construction costs. 
     Workpiece Support Finger Actuator 
     The preferred wafer support also includes a plurality of wafer-engaging fingers  979  positioned about the periphery of the wafer or other workpiece. FIG. 27 shows the front face of the outer rotor part  940  in a face-up orientation with fingers  979  extending therefrom. The preferred fingers are J-shaped and mounted for pivotal action about a finger pivot axes  953 . The pivotal action preferably ranges between an outboard position and an inboard position. In the outboard position the J-shaped fingers are positioned outwardly and clear of the wafer peripheral edge. A preferred outboard position is illustrated in FIG.  27 . In the outboard position the hooked portions of the J-shaped fingers are oriented at approximately  15  angular degrees outward from a line drawn tangent to the periphery of the wafer adjacent to the finger. In the inboard position the fingers are positioned inwardly to engage the wafer, as shown in FIG.  28 . In the inboard position the hooked portions of the J-shaped fingers are oriented at approximately  45  angular degrees inward from a line drawn tangent to the periphery of the wafer adjacent to the finger. 
     The face of the rotor assembly is provided with workpiece standoff supports  721  which are in complementary position to the engagement ends of the fingers when the fingers are in a retracted position to hold the wafer. This construction securely captures the wafer or other workpiece between the fingers and the standoffs. 
     In addition to the pivotal action of the engagement fingers, the fingers are also move axially toward and away from the face of the rotor. In the inboard position the fingers are retracted toward the wafer to engage the exposed, front face of the wafer along a marginal band adjacent to the periphery of the wafer. In the outboard position the fingers are extended away from the face of the wafer to prevent rubbing action as the fingers pivot away from the wafer. This compound action including both a pivot component and an axial component is accomplished using a finger actuator transmission  960  shown in perspective relationship to the rotor in FIG.  26 . Transmissions  960  are mounted within the transmission receptacles  937  of the inner rotor part  934 . The transmissions are further mounted by transmission retainers  951  which are secured by fasteners to inner rotor part  934 . 
     FIG. 29 shows the finger actuator transmission  960  in greater detail. The lower end of transmission  960  includes a finger head mounting receptacle  954 . Receptacle  954  is advantageously provided with a locking feature included to secure the fingers in the receptacles. As shown, the receptacle includes a convoluted, bayonet-type, locking pin groove  955 . Locking pin groove  955  receives a transversely mounted finger mounting pin  956  (see FIG. 32) which is a rolled or other suitable pin secured in the head of the finger assembly. 
     FIGS. 29,  30 , and  31  detail the preferred construction of the actuator transmissions  960 . The transmissions include a transmission base  961  which is provided with a mounting cutout  962  which is borne upon by the retainers  951  when installed in the rotor. The base also includes a central passageway within which is received a transmission shaft  963 . Shaft  963  can both pivot and move axially within the central passageway. The shaft and base  961  are constructed to interact in a manner which controls the relative motion of the shaft. This is done to provide the compound pivotal and axial movement of the shaft and a finger  979  which is held therein. As shown, the inactive mechanism is provided in the form of a shaft channel or groove  964  which is engaged by a shaft camming control member  965 . The camming action of the groove is provide by a helical advance over a pivotal movement range of approximately 60 degrees of rotation. The associate axial travel is in the range of approximately 5-20 millimeters, more preferably about 10-15 millimeters. 
     The camming control member  965  is advantageously in the form of a ball  966  held into the groove  964  using a ball support fastener  967 . Fastener  967  has a ball socket which receives portions of the ball. Fastener  967  also serves as a convenient electrical contact terminal when electricity is supplied to the fingers  979 . 
     The shaft  963  is provided with an interior shaft passageway  968  which receives a spring retainer  969 . Spring retainer  969  has an engagement head which mechanically engages with a finger mounting spring  938 . The spring  938  serves to bias a finger assembly into a locked position using the locking pin  956  held in biased relationship by groove  955 . Spring retainer  969  is secured in the passageway by a set screw  939 . 
     FIG. 31 also shows that the transmission  960  preferably includes a transmission head  656 . Transmission head  656  is connected to the upper end of shaft  963  using a bearing  657  which allows the shaft to pivot relative to the head pieces  658  and  659 . Head pieces  658  and  659  capture the bearing between them, and are joined by head fasteners  660 . The head fasteners  660  thread into a pair of head guide rods  661 . Head guide rods  661  are slidably received by two guide passageways  662  formed in the transmission base  961 . The head assembly is biased upwardly by two head bias springs  664 . Engagement between ball  966  and groove  964  limits the upward movement of the head assembly under action by springs  664 . 
     The lower end of shaft  963  is sealed to the base  961  using a shaft seal  667  which helps to keep any abraded metal within the transmission and prevent contamination toward the fingers  979 . Shaft  963 , also has a transverse hole  665  which is used as an electrical connection feature that receives a wire (not shown) run from the slip ring down the rotor shaft. The wire is secured in hole  665  by a set screw (not shown). 
     The transmissions  960  are activated by a transmission head depression ring  683  (see FIG.  24 ). Depression ring  683 , is connected to an operator output connection ring  684  (see FIG.  25 ). The operator output connection ring is secured by fasteners to the output shafts of pneumatic actuator engines  691 . FIG. 25 also shows pneumatic manifolds  692  used to supply the actuator engines. The preferred construction shows three actuator engines  691  which have outputs which move upwardly and downwardly to depress the transmission heads  658  and operate the fingers in the compound axial and pivotal motion already described. The actuator engine outputs are extended to depress rings  683  and  684 , and to depress the transmission heads  658  thus causing the fingers  979  to move from the inboard retracted positions of FIG. 28 to the outboard extended positions of FIG.  27 . 
     Electrode Fingers With Submerged Conductive Current Transfer Areas 
     FIGS. 32-39 show a number of different electrode finger constructions. The different constructions shown have particular application to differing applications. FIG. 32 shows a finger assembly  631  having intended application for contacting a semiconductor wafer during blanket plating of copper. Finger assembly  631  includes a finger shaft  632  which is formed in a J-shape and made from an electrically conductive material, such as stainless steel or tungsten. The finger assembly also preferably includes an integral finger head  633  which is received into the receptacle  954  of the actuator transmission  960 . The head has a pin aperture which receives the locking pin  956  therein for engagement with the locking groove  955  formed in the receptacle of the actuator transmission. 
     Finger assembly  631  also preferably includes dielectric sheathing  634  and  635 . Dielectric sheathing  634  and  635  is advantageously made from a polyvinylidene fluoride coating or layer applied to the shaft of the finger. The dielectric sheathing is preferably provided upon only limited portions of the electrode shaft and adjacent the contact head  636 . The contact head has a contact face  637  which directly bears upon the wafer to pass electrical current between the electrode and wafer. The contact face  637  is approximately equal to a fluid submersion boundary  639 . The submersion boundary indicates the approximate level of the plating liquid during processing. 
     The limited coverage of the dielectric sheathing is for the purpose of improving the uniformity of plating performed upon semiconductor workpieces held in the wafer support. It is believed that the submersible surfaces of the electrode finger are best provided with dielectric sheathing segments which comprise between approximately 25 percent and 75 percent of the submersible area of the electrode. These amounts do not consider the contact face as part of the areas. FIG. 32 show two segments  634  and  635  which cover about 50 percent of the electrode finger shaft exterior surfaces from the submersion line  639  downward, as positioned in a plating liquid bath during processing. The first dielectric segment  634  is adjacent to the contact face  637  a first electrically conductive segment  642  exists between the dielectric segment  634  and the contact face  637 . A second electrically conductive segment  643  exists between first and second dielectric segments  634  and  635 . A third electrically conductive segment  644  exists between the second dielectric segment  635  and submersion line  639 . The electrically conductive segments  642 - 644  provide current transfer areas which cause plating current that is supplied through the finger head  633  to be directly passed to the plating liquid contained in a plating bath. This is believed to provide a more uniform current density and more uniform voltage profile across the surface of a wafer which is being blanket plated with copper or other plating metals. 
     FIG. 33 shows another plating system workpiece support electrode  651  having many of the same features as electrode  631  described immediately above. The same reference numerals have been used to designate similar parts. Differences between finger electrodes  651  and  631  will now be described. Electrode  651  has three current transfer areas  642 - 644 . The size and shape of areas  642 - 644  are somewhat different from the corresponding areas of electrode  631 . More specifically, the second and third current transfer areas  643  and  644  are elongated along the shaft. The second dielectric sheath segment  635  is shortened. A third dielectric segment  653  has been included. The third dielectric sheath  654  forms the submerged dielectric segment  653  and also extends above the submersion line  639  to head  633 . The area of the submerged current transfer segments is between 25 and 75 percent of the submerged surface area, more particularly, about 50 percent. 
     Electrode  651  is also provided with a distal contact insert part  655 . Insert part  655  is received within an insert receptacle  616  formed in the distal end of the electrode shaft. The insert contact tip  655  defines a contact face  617  which bears upon a wafer being held. The insert contact part is made from a conductive material which is preferably non-corrosive material, such as platinum or stainless steel. 
     FIG. 34 shows a further electrode finger construction in the form of electrode finger  979 . Similar parts to electrode fingers  631  and  651  are similarly numbered in this figure. The electrode shaft is covered by a dielectric sheath  621  which largely covers the electrode shaft and leaves only a first current conductive area  642  which is immediately adjacent to the contact face  637 . This construction is contrasted to the electrodes  631  and  651  because electrode finger  979  does not have current transfer areas which comprise  25  percent of the submerged portion of the electrode. It also does not have current transfer areas which are exposed in a manner which is separated by a dielectric segment interpositioned between the contact face  637  and the removed or remote current conductive segment. 
     FIG. 35 shows a further electrode finger  601  which has submerged current transfer areas  642 - 644 . It also has dielectric segments  634  and  635 . Dielectric segment  635  of this figure has a differing shape and coverage area as compared to the other electrodes discussed above. In this construction the dielectric sheath extends along the outer curvature of the electrode J-bend. Curved upper edges extend so as to provide an overlying web portion  603  which covers the inner curvature of the J-bend. Performance in terms of plating uniformity has been found to be superior in some processes which employed the electrode of this figure. 
     The electrodes  631 ,  651  and  601  are preferably used in novel processes according to this invention. These processes include contacting a surface of the semiconductor article or workpiece with an electrode at a contact face thereof. The methods also include submersing a portion or portions of the electrode into a plating bath containing a plating liquid which is typically a solution and mixture have various components known in the art. The methods also preferably include wetting a processed surface of the semiconductor article with the plating bath. Further included is the step of moving or conducting electrical current through the electrode and plating bath to perform an electroplating action to occur upon at least the processed surface of the wafer or other article. The methods further advantageously include diverting a portion of the electrical current directly between the electrode and the plating bath along at least one electrically conductive segment of the electrode. The electrically conductive segment is preferably spaced from the contact face a substantial distance, such as greater than 5 millimeters, and preferably is spaced therefrom by an intervening dielectric sheath. 
     Electrode Fingers With Dielectric Sheaths Covering Submerged Areas 
     FIG. 36 shows another electrode finger  681  which is similar to electrode finger  651 . Finger  681  is similar to finger  651  except it includes a full dielectric sheath  682  which extends from above submersion line  639  to contact insert side walls  619 . This construction preferably uses a coating layer  682 , such as from polyvinylidene fluoride, which can be applied by dipping or otherwise forming the layer over the shaft of the electrode. This construction includes the dielectric layer over the distal end of the electrode shaft and into sealing relationship with the side walls of the insert contact part or tip  655 . The dielectric coating or other layer  682  excludes corrosive processing fluids. Since the contact tip is preferably made from a non-corrosive material, such as platinum, the only material of the electrode which is exposed to direct corrosive action is the non-corrosive tip which is able to maintain good service despite the difficult operating environment. 
     Additionally, the construction of electrode  681  is particularly advantageous because the joint formed between the inserted contact tip  655  and receptacle  616  is covered and protected from direct exposure to the corrosive plating liquid and fumes present in the processing chamber. 
     The invention further includes methods for plating metals onto the surface of a semiconductor workpiece using electrode finger  681 . The methods include contacting a surface of the workpiece with an electrode assembly using a contact face, such as face  617 , on a contact part, such as contact insert part  655 . The contact insert is mounted on the distal end of the electrode shaft. It is further preferably provided with a dielectric layer formed about the distal end in sealing relationship against the contact part. The methods further preferably include submersing or otherwise wetting a processed surface of the workpiece, such as in a plating bath liquid used to plate the workpiece with a plating material. The methods also preferably include excluding the plating bath liquefied from the contact part joint, such as the joint formed between the contact part  655  and receptacle  616 . The methods further include electroplating the workpiece with plating material by passing electrical current through the contact part and between the semiconductor workpiece and electrode assembly. The contact face plating layer is more preferably formed from the plating material as is described below in additional detail. The method is most preferably used to plate copper onto the surface of semiconductor materials, such as silicon or oxides thereof. 
     Pre-Conditioning of Electrode Contact Faces 
     FIGS. 37 and 38 illustrates a further electrode construction in accordance with further inventive aspects of the workpiece support systems and methods described herein. FIG. 37 shows distal end portions of an electrode  614 . Electrode  614  is otherwise similar to electrode  681  described above. At the distal end of electrode finger  614  is a distal exposed surface  615  is made from a suitable material, such as stainless steel or tungsten. A dielectric sheath  616  is advantageously provided along the exterior portions of the electrode adjacent to the distal exposed surface  615 . 
     FIG. 38 shows the electrode  614  with a deposited contact face plating layer  618  formed thereon. The layer  618  is preferably a layer made from the same or a very similar material as is being plated onto the semiconductor workpieces with which electrode  614  is to be used. For example, if copper is being plated onto the semiconductor device, then the layer  618  is a layer plated from the same plating, bath or from a plating bath which will provide a layer  618  which is the same or very similar to the constituency of the copper deposited onto the semiconductor device being plated. In a preferred manner of carrying out this invention, the exposed distal surfaces  615  are placed into a plating bath and electrical current is conducted through the bath and distal end of the electrode  614 . This causes a plating action to occur which deposits the layer  618 . The resulting layer is preferably at least 1 micron in thickness, more preferably in the approximate range of 1-100 microns thick. 
     This method and resulting construction results in a pre-conditioned electrode contact surface which is of the same or very similar material as plated onto the semiconductor device during the later plating operation. The use of the same or similar materials prevents galvanic or other types of chemical reactions from developing due to dissimilarity of the metals involved. 
     The invention further includes additional methods for plating metals onto the surface of a semiconductor workpiece. The preferred methods include contacting a surface of the semiconductor workpiece with an electrode at a contact face forming a part of the electrode. The contact face is covered or substantially covered by a contact face plating layer. The contact face plating layer is formed from a contact face plating material which is the same or chemically similar to thee plating material which is to be plated onto the semiconductor workpiece during processing. The methods also preferably include submersing or otherwise wetting a processed surface of the workpiece into a plating bath or using a plating liquid or fluid. Other means for depositing the plating material as a contact face layer may alternatively be used. The methods further include electroplating workpiece plating material onto the semiconductor workpiece by passing electrical current between the workpiece and the electrode having such contact face plating layer. The methods are of particular advantage in the plating of copper onto semiconductors using a copper contact face plating layer. 
     Methods Using Workpiece-Engaging Electrode Assembly With Sealing Boot 
     FIG. 39 shows a further electrode finger  583  which has features similar to  651  and such similar features are identified with the same reference numbers. Electrode finger  583  differs from finger  651  in that the electrode shaft  584  is covered between the head  633  to the distal end of the electrode shaft with a cover or boot  585 . Boot  585  is preferably made in a manner which provides a continuous cover from near the electrode head  633  to a distal contact lip  586 . The boot includes additional features adjacent the contact insert part  655 . More specifically, the boot includes a skirt portion  587  which extends above the electrode shaft distal end surface  588 . The contact face  617  of (the insert part  655  is preferably about even with the distal contact lip  586  which is formed upon the end of the skirt portion  587 . The skirt portion serves as a deformable seal which comes into contact with a surface of a wafer or other semiconductor workpiece being contacted. 
     FIGS. 40 and 41 illustrate novel methods which advantageously utilize the improved features of electrode finger  583 . The methods involve plating metals onto the surface of semiconductor workpieces, specifically onto a semiconductor wafer W which has a substrate or other subjacent layer  561  which has been previously provided with a thin metallic seed layer  562  which is shown by a heavy black line in that figure. A via or other opening  563  exists in a photoresist layer  564  which overlies the substrate and seed layers. 
     FIG. 40 shows the electrode  583  poised in a disengaged position in preparation for contact with the surface. FIG. 41 shows the electrode  583  retracted against the surface of the workpiece. In the engaged position the contact face  617  is extended through the opening  563  and into direct electrical contact with exposed areas of the seed layer  562  which are not covered by the layer of photoresist or other covering layer. A seal is formed by depressing the skirt  587  and attached lip  586  against the outer surface of the photoresist layer  564 . 
     The novel methods include selecting an electrode assembly having desired features, such the features of electrode finger  583 . More specifically, the selecting step preferably includes selecting an electrode assembly having an electrode contact which is surrounded by an electrode boot or other sealing member. The methods also include engaging coated surface portions, such as photoresist layer  564 , with the sealing member or boot. The sealing can occur about a continuous peripheral sealing line, such as defined by the engagement of lip  586  against the photoresist surface. It is important to engage the lip against the photoresist surface and not against the seed layer  562  because sealing against the seed layer can cause erosive or corrosive effects to occur at or near the line or area of engagement of the boot with the seed layer. Such erosive or corrosive actions can cause the seed layer to become discontinuous or even totally isolated. A discontinuous or isolated contact region will lead to electroplating failure because the needed current will not be communicated in an even manner to the areas adjacent to the electrode which need current to accomplish plating. The engagement of the seal against the coating causes a sealed space to be enclosed within the seal by the electrode boot and the processed surface of the workpiece. 
     The novel methods further include enclosing a via or other opening within the seal. The via is present on the processed surface and has associated exposed seed layer portions therein for allowing electrical contact to be made. The via is needed to allow direct contact between the contact face of the electrode finger assembly and the seed layer which is used to communicate electrical current across the wafer for electroplating a metal thereonto. Thus, the methods further include contacting the seed layer through the via with the electrode contact to form an electrically conductive connection between the electrode assembly and the seed layer. This contacting step is advantageously performed using a contact face which bears upon the seed layer and is enclosed with the sealed space. Other desirable attributes explained hereinabove in connection with other electrodes can also be utilized to advantage in performing this process. 
     The methods still further include wetting the processed surface of the workpiece with a plating or other processing liquid. This is typically done by lowering the wafer holder into position to bring the outer, processed surface of the wafer into direct contact with a plating liquid held in a plating bath, such as described elsewhere herein in additional detail. 
     The methods also preferably include passing electrical current through the electrode and plating bath to cause electroplating to occur upon exposed seed layer areas of the processed surface. Such exposed seed layer areas may be trenches, vias or other features where the photoresist layer  564  is not present to cover the seed layer  562 . The electrical current causes electroplating to occur on such exposed seed layer areas. 
     Still further, the methods preferably include excluding plating or other processing liquid from the sealed space to substantially reduce or eliminate plating or other action in the area immediate adjacent to the contact with the electrode. 
     The methods described above are of particular relevance to plating copper onto semiconductors. 
     Plating Bowl Assembly 
     FIG. 42 shows an electroplating bowl assembly  303 . The process bowl assembly consists of a process bowl or plating vessel  316  having an outer bowl side wall  317 , bowl bottom  319 , and bowl rim assembly  314 . The process bowl is preferably circular in horizontal cross-section and generally cylindrical in shape although other shapes of process bowl may be possible. 
     The invention further advantageously includes a cup assembly  320  which is disposed within process bowl vessel  316 . Cup assembly  320  includes a fluid cup portion  321  having a cup side  322  and a cup bottom  323 . As with the outer process bowl, the fluid cup  321  is preferably circular in horizontal cross-section and cylindrical in shape. The cup assembly also has a depending skirt  371  which extends below the cup bottom  323  and has flutes  372  open therethrough for fluid communication and release of any gas that might collect as the chamber below fills with liquid. The cup assembly can be made using upper and lower portions which couple together at a cup main joint  387 . The cup is preferably made from polypropylene or other suitable material, which is advantageously dielectric. 
     The lower opening in the cup bottom wall is connected to a riser tube  361  which is adjustable in height relative thereto by a threaded connection. The riser tube seals between the bottom wall  319  of the process bowl and the cup bottom  323 . The riser tube is preferably made from polypropylene or other suitable dielectric material. A fitting  362  connects the riser tube  361  and the fluid inlet line  325  to allow adjustment of the anode vertical position. The fitting  362  can accommodate height adjustment of both the riser tube and inlet line  325 . The inlet line is made from a conductive material, such as titanium and is used to conduct electrical current to the anode  334 , as well as supply fluid to the cup. 
     Process fluid is provided to the cup through fluid inlet line  325 . The fluid inlet line rises through riser tube  361  and bowl bottom opening  327  and through cup fluid inlet openings  324 . Plating fluid fills the cup portion  321  through opening  324  as supplied by a plating fluid pump (not shown) or other suitable supply which provides the fluid under at least some pressure for delivery. 
     The upper edge of the cup side wall  322  forms a weir which determines the level of plating liquid within the cup. Excess fluid pours over this top edge surface into the overflow chamber  345 . The fluid held in the overflow chamber  345  is sensed by two level detectors  351  and  352 . One level detector is used to sense a desired high level and the other is used to sense an overfull condition. The level of liquid is preferably maintained within a desired range, for stability of operation. This can be done using several different outflow configurations. A preferred configuration is to sense the high level using detector  351  and then drain fluid through a drain line as controlled by a control valve. It is also possible to use a standpipe arrangement (not illustrate), and such is used as a final, overflow protection device in the preferred plating station  303 . More complex level controls are also possible. 
     The outflow liquid from chamber  345  is preferably returned to a suitable reservoir. The liquid can then be treated with additional plating chemicals or other constituents of the plating or other process liquid and used again. 
     The plating bowl assembly  303  further includes an anode  334 . In the preferred uses according to this invention, the anode is a consumable anode used in connection with the plating of copper or other metals onto semiconductor materials. The specific anode will vary depending upon the metal being plated and other specifics of the plating liquid being used. A number of different consumable anodes which are commercially available may be used as anode  334 . 
     FIG. 42 also shows a diffusion plate  375  provide above the anode  334  for rendering the fluid plating bath above the diffusion plate with less turbulence. Fluid passages are provided over all or a portion of the diffusion plate to allow fluid communication therethrough. The height of the diffusion plate is adjustable using three diffuser height adjustment mechanisms  386  and secured by three mounting fasteners  389 . 
     Plating Anode Shield 
     The invention also includes an anode shield  393  which can be secured to the consumable anode  334  using anode shield fasteners  394 . The anode shield and anode shield fasteners are preferably made from a dielectric material, such as polyvinylidene fluoride or polypropylene. The anode shield is advantageously about 2-5 millimeters thick, more preferably about 3 millimeters thick. 
     The anode shield serves to electrically isolate and physically protect the back side of the anode. It also reduces the consumption of organic plating liquid additives consumed. Although the exact mechanism may not be known at this time, the anode shield is believed to prevent disruption of certain materials which develop over time on the back side of the anode. If the anode is left unshielded the organic chemical plating additives are consumed at a significantly greater rate. With the shield in place these additive are consumed less. The shield is preferably positioned on the anode so as to shield it from direct impingement by the incoming plating liquid. 
     The invention thus also include methods for plating which include other method steps described herein in combination with shielding a consumable anode from direct flow of plating liquids using a dielectric anode shield. 
     As illustrated and described above, the electrodes used to conduct plating power to the workpiece may develop deposits. This is particularly true in those instances in which the electrodes are directly exposed to the electrolyte during electroplating. Accordingly, the reactor may be operated to execute at least two operational cycles: a normal cycle and a cleaning cycle. More particularly, the reactor is operated during the normal cycle to electroplate at least one metal on a surface of one or more semiconductor workpieces. The reactor is then operated during a cleaning cycle to clean the electrodes that were used to electroplate the metal by removing metal that was deposited on the electrodes during the normal operating cycle. The cleaning cycle is executed as an operational step that is separate from the normal cycle in which the workpieces are electroplated. The cleaning cycle takes place “in-situ” in that the cleaning of the electrodes takes place at the site of the reactor. 
     In accordance with one specific embodiment of the method, the electroplating and in-situ cleaning processes are performed in an operational sequence that begins by establishing electrical contact between at least one surface of the workpiece and the electrode. At least one surface of the workpiece is then brought into electrical contact with an electrolyte within the reactor base after which a current is passed through the electrode and the at least one surface of the semiconductor workpiece using an electrical power supply. This application of power results in the electroplating of a metal from the electrolyte onto the surface of the workpiece. The workpiece is then removed from electrical contact with the electrode and the electrode is placed into the electrolyte within the reactor base without a workpiece. With the electrode in contact with the electrolyte, a further current is generated by the electrical power supply for flow between the electrode and the electrolyte in a direction opposite to the direction of current flow during electroplating. The voltage potential used to generate this current may be in the range of about 0.1 to 100 volts, with a range of 1 to 10 volts being suitable. The voltage used may be selected so that it is dependent on the number of workpieces that are processed during the normal cycle of operation. Further, this potential may be generated between the electrode and the anode or, alternatively, between the electrode and an auxiliary electrode. Application of this reversed power causes metal previously plated onto the electrode to electrochemically disperse into the electrolyte and leaves the electrode clean for subsequent use in the electroplating of a further set of workpieces. 
     To enhance cleaning of the electrodes, the reactor head may be rotated in the electrolyte during the cleaning cycle. For example, the reactor head may be rotated at an angular velocity of about 1 to 300 revolutions per minute, with a smaller range of 10 to 100 revolutions per minute also being suitable. The rotation may take place concurrently with the application of the reverse current and may occasionally reverse direction. For example, the rotation may be reversed every 10 seconds to about every one minute.