Abstract:
A device for processing wafer-shaped articles comprises a rotary chuck mounted for rotation within a surrounding enclosure. The rotary chuck has mounted therein at least one sensor, a microprocessor connected to the at least one sensor so as to receive output signals therefrom, and a wireless transmitter connected to the microprocessor so as to receive output signals therefrom and transmit signals exteriorly of the device.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates generally to an apparatus for processing wafer-shaped articles, such as semiconductor wafers, and more particularly relates to such an apparatus comprising a spin chuck comprising an in situ temperature monitoring capability. 
         [0003]    2. Description of Related Art 
         [0004]    Semiconductor wafers are subjected to various surface treatment processes such as etching, cleaning, polishing and material deposition. To accommodate such processes, a single wafer may be supported in relation to one or more treatment fluid nozzles by a chuck associated with a rotatable carrier, as is described for example in U.S. Pat. Nos. 4,903,717 and 5,513,668. 
         [0005]    Alternatively, a chuck in the form of a ring rotor adapted to support a wafer may be located within a closed process chamber and driven without physical contact through an active magnetic bearing, as is described for example in International Publication No. WO 2007/101764 and U.S. Pat. No. 6,485,531. 
         [0006]    It can be important to monitor process conditions occurring during wafer processing, so as to maintain the process parameters within desired specifications. One technique for monitoring process conditions involves the use of a test wafer that is equipped with sensors and is connected via a conductor to a transceiver that reads out the sensed data and communicates that data to a monitoring station, as described for example in U.S. Pat. No. 6,889,568. 
         [0007]    It would be desirable, however, to be able to monitor wafer processing conditions in situ, during processing of an actual work piece rather than a test wafer. It would furthermore be desirable to enable such monitoring with a system that requires a minimum of intervention to the processing environment. 
       SUMMARY OF THE INVENTION 
       [0008]    Thus, in one aspect, the present invention relates to a device for processing wafer-shaped articles, comprising a rotary chuck mounted for rotation within a surrounding enclosure. The rotary chuck has mounted therein at least one sensor, a microprocessor connected to the at least one sensor so as to receive output signals therefrom, and a wireless transmitter connected to the microprocessor so as to receive output signals therefrom and transmit signals exteriorly of the device. 
         [0009]    In preferred embodiments of the device according to the present invention, the rotary chuck comprises a circular series of pins positioned so as to contact an edge region of a wafer-shaped article of a predetermined diameter. 
         [0010]    In preferred embodiments of the device according to the present invention, the circular series of pins projects from an upper surface of the rotary chuck, and the at least one sensor, the microprocessor and the wireless transmitter are mounted beneath the upper surface of the rotary chuck. 
         [0011]    In preferred embodiments of the device according to the present invention, a battery is mounted in the rotary chuck and supplies power to at least the microprocessor and the wireless transmitter. 
         [0012]    In preferred embodiments of the device according to the present invention, a coil is mounted in the rotary chuck and is electrically connected to the battery so as to permit the battery to be recharged by a current induced wirelessly in the coil. 
         [0013]    In preferred embodiments of the device according to the present invention, a magnet is mounted in a stationary manner within the enclosure and adjacent the rotary chuck such that upon rotation of the rotary chuck a current is induced in the coil. 
         [0014]    In preferred embodiments of the device according to the present invention, a capacitor is mounted in the rotary chuck and is connected to at least the microprocessor and the wireless transmitter. 
         [0015]    In preferred embodiments of the device according to the present invention, a coil is mounted in the rotary chuck and is electrically connected to the capacitor so as to permit the capacitor to be charged by a current induced wirelessly in the coil. 
         [0016]    In preferred embodiments of the device according to the present invention, a magnet is mounted in a stationary manner within the enclosure and adjacent the rotary chuck such that upon rotation of the rotary chuck a current is induced in the coil. 
         [0017]    In preferred embodiments of the device according to the present invention, the at least one sensor, the microprocessor and the wireless transmitter are positioned such that their weight is distributed evenly with respect to an axis of rotation of the rotary chuck. 
         [0018]    In preferred embodiments of the device according to the present invention, the at least one sensor comprises at least three sensors positioned beneath an upper surface of the rotary chuck and symmetrically with respect to an axis of rotation of the rotary chuck. 
         [0019]    In preferred embodiments of the device according to the present invention, the at least one sensor comprises at least one temperature sensor. 
         [0020]    In preferred embodiments of the device according to the present invention, the at least one sensor comprises at least one first temperature sensor that senses temperature by contact with an object whose temperature is to be sensed, and at least one second temperature sensor that senses temperature without contacting an object whose temperature is to be sensed. 
         [0021]    In preferred embodiments of the device according to the present invention, a control station is positioned exteriorly of the enclosure, the control station comprising a controller for controlling operations of the rotary chuck, the control station further comprising a wireless receiver that receives signals from the wireless transmitter. 
         [0022]    In preferred embodiments of the device according to the present invention, the wireless transmitter is a Bluetooth transceiver. 
         [0023]    In preferred embodiments of the device according to the present invention, the at least one sensor comprises a g-force sensor. Alternatively, PT100 or PT1000 sensors may be used for temperature measurement, and/or a humidity sensor or an infrared temperature sensor may also be used. 
         [0024]    In preferred embodiments of the device according to the present invention, the at least one sensor comprises a thermocouple. 
         [0025]    In another aspect, the present invention relates to a rotary chuck for processing wafer-shaped articles, comprising a chuck body having mounted therein at least one sensor, a microprocessor connected to the at least one sensor so as to receive output signals therefrom, and a wireless transmitter connected to the microprocessor so as to receive output signals therefrom and transmit signals to a remote receiver. 
         [0026]    In preferred embodiments of the rotary chuck according to the present invention, the chuck body comprises a circular series of pins positioned so as to contact an edge region of a wafer-shaped article of a predetermined diameter. 
         [0027]    In preferred embodiments of the rotary chuck according to the present invention, the circular series of pins projects from an upper surface of the chuck body, and the at least one sensor, the microprocessor and the wireless transmitter are mounted beneath the upper surface of the chuck body. 
         [0028]    In preferred embodiments of the rotary chuck according to the present invention, a battery is mounted in the chuck body and supplies power to at least the microprocessor and the wireless transmitter. 
         [0029]    In preferred embodiments of the rotary chuck according to the present invention, a coil is mounted in the chuck body and is electrically connected to the battery so as to permit the battery to be recharged by a current induced wirelessly in the coil. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]    Other objects, features and advantages of the invention will become more apparent after reading the following detailed description of preferred embodiments of the invention, given with reference to the accompanying drawings, in which: 
           [0031]      FIG. 1  is an explanatory cross-sectional side view of an apparatus according to a first embodiment of the invention; 
           [0032]      FIG. 2  is an explanatory cross-sectional side view of an apparatus according to a second embodiment of the invention; 
           [0033]      FIG. 3  is a plan view of the upper side of the plate  28  shown in  FIG. 1 ; and 
           [0034]      FIG. 4  is a plan view of the lower side of the plate  28  shown in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0035]    Referring now to  FIG. 1 , a device for treating surfaces of wafer-shaped articles according to a first embodiment of the invention comprises a closed process chamber  15 , in which is arranged an annular spin chuck  16 . Spin chuck  16  is a magnetic rotor that is surrounded by a magnetic stator  17  positioned outside the chamber  15 , so that the magnetic rotor is freely rotating and levitating within the chamber  15  without touching the chamber walls. The chamber  15  is closed at its upper end by lid  14  rigidly secured thereto. 
         [0036]    Further structural details of such a magnetic rotor chuck are described, for example, in commonly-owned U.S. patent application publication no. 2013/0134128. 
         [0037]    The annular spin chuck  16  has a circular series of downwardly-depending gripping pins  19 , which releasably hold a wafer W during processing. A lower dispense unit  22  is provided so as to supply liquid and/or gas to the side of the wafer W that faces downwardly within chamber  15 . A heater  31  is disposed within the chamber  15 , so as to heat the wafer W to a desired temperature depending upon the process being performed. Heater  31  preferably comprises a multitude of blue LED lamps, whose radiation output tends to be absorbed preferentially by silicon wafers relative to the components of the chamber  15 . 
         [0038]    An upper dispense unit comprises an outer gas conduit  27  and an inner liquid conduit  25  arranged coaxially within the outer gas conduit  25 . Conduits  25 ,  27  both traverse the lid  14 , and permit liquid and gas to be supplied to the side of the wafer W that faces upwardly within chamber  15 . 
         [0039]    A plate  28  is rigidly secured to the annular spin chuck  16 , or in the alternative may be formed integrally therewith. Plate  28  therefore rotates with the spin chuck  16  and is a part of the spin chuck  16 . The upper dispense unit passes through a central opening formed in plate  28 . Plate  28  may comprise additional through apertures (not shown), so as to act as a gas showerhead for dispensing gas in a distributed manner into the chamber  15 . 
         [0040]    Plate  28  carries various process monitoring equipment, as shown more fully in  FIGS. 3 and 4 . In this embodiment, plate  28  carries six temperature sensors  52 - 1 ,  52 - 2 ,  52 - 3 ,  52 - 4 ,  52 - 5 ,  52 - 6 , which are positioned on the side of the plate  29  that faces the wafer W, which in this case is the downwardly-facing side of plate  28 . Temperature sensors  52 - 1  . . .  52 - 6  may be of the contact or non-contact type, or they may be a combination of both types. A preferred example of a contact type temperature sensor is a thermocouple. It will be understood that a “contact” sensor in this context does not connote a sensor that contacts the wafer W, but rather a sensor that reads the temperature of the ambient with which it is in contact. A preferred example of a non-contact temperature sensor is an infrared temperature sensor. 
         [0041]    Temperature sensors  52 - 1 ,  52 - 2 ,  52 - 3 ,  52 - 4 ,  52 - 5 ,  52 - 6  each provide a signal representing the sensed temperature to respective conductors  54 - 1 ,  54 - 2 ,  54 - 3 ,  54 - 4 ,  54 - 5 ,  54 - 6 , as shown in  FIG. 4 , which conductors pass through the plate  28  and are joined with the conductors  58  and  59  formed on the opposite side of plate  28 , as shown in  FIG. 3 . 
         [0042]    In particular, each sensor  52 - 1 ,  52 - 2 ,  52 - 3 ,  52 - 4 ,  52 - 5 ,  52 - 6  thereby provides its signal output to its respective sensor IC  51 - 1 ,  51 - 2 ,  51 - 3 ,  51 - 4 ,  51 - 5 ,  51 - 6 , which processes and outputs a temperature readout signal via its respective conductor  59  to the circular bus  58 . Bus  58  provides for communication between sensor ICs  51 - 1 , . . .  51 - 6 , and microprocessor  53  and Bluetooth transceiver  55 . Bus  58  also allows these components to be powered via battery  64 , which in turn can be charged by current induced wirelessly in the induction coil  57 . 
         [0043]    The components shown in  FIG. 3  are mounted on the plate that faces away from the wafer W undergoing processing, which in the case of  FIG. 1  is the upwardly-facing surface of plate  28 . One or more of the sensors  52 - 1 ,  52 - 2 ,  52 - 3 ,  52 - 4 ,  52 - 5 ,  52 - 6  may be a g-force sensor rather than a temperature sensor. One or more of the sensors  52 - 1 ,  52 - 2 ,  52 - 3 ,  52 - 4 ,  52 - 5 ,  52 - 6  may be, instead of a temperature sensor, a sensor of processing chamber pressure, gas flow rate within the chamber  15 , gaseous chemical composition within the chamber, ion current density, ion current energy, light energy density, and vibration of the wafer, in addition to or instead of a g-force sensor. 
         [0044]    The outputs of sensor ICs  51 - 1 , . . .  51 - 6  are supplied to microprocessor  53 , which integrates the data and provides an output to Bluetooth transceiver  55 . As shown in  FIG. 1 , Bluetooth transceiver  55  communicates wirelessly with the Bluetooth transceiver  62  of a control station  60 . The data supplied to control station  60  via Bluetooth transceivers  55 ,  62  may thus be used to control various process parameters, such as duration of heating, speed and duration of rotation of the spin chuck, timing and duration of dispensing of process liquids, etc. 
         [0045]    Battery  64  may instead be a capacitor that is charged via the induction coil  57 . In  FIG. 1 , an embodiment is shown wherein a magnet  56  is mounted in a stationary manner within the chamber  15 , and adjacent the rotary chuck  16  such that a current is induced in the coil  57  when the chuck is rotated. This embodiment therefore has the advantage of generating the power necessary for the in situ monitoring system. 
         [0046]      FIG. 2  shows an alternative embodiment in which the chuck is rotated by a conventional electric motor. The chuck  21  of  FIG. 2  comprises gripping fingers  19  extending upwardly from the chuck, which engage the peripheral edge of a wafer W to position the wafer a fixed distance above the chuck&#39;s upper surface. 
         [0047]    A treatment liquid dispenser comprises liquid conduit  24  which extends axially through a central bore in chuck  10  to a liquid nozzle  6  located at the upper surface of the chuck. Liquid conduit  24  and liquid nozzle  6  are adapted to conduct one or more treatment liquids to the back surface of a wafer, preferably while the wafer W and chuck  10  are rotating. 
         [0048]    The spin chuck  21  includes a non-rotating nozzle head  20  and a base body  10 , which is mounted onto a rotating support plate  41 . The support plate  41  is connected to a rotating hollow shaft  42  (rotor), which is part of a hollow shaft motor  40 . The hollow shaft motor has an outer stator  40  and an inner rotor. The stator  40  is connected to a machine frame part  43 ,  44  with a frame plate  43  and a connecting part  44 . The cylinder-like non-rotating nozzle head  20  is connected to the connecting part  44 . 
         [0049]    Plate  28  is integrated into the upper cover of chuck  21  in this embodiment. Thus, for example, each of the gripping pins  19  passes through a corresponding opening formed in the upper cover. However, the layout of the monitoring system on plate  28  in this embodiment is the same as in the preceding embodiment. The main difference is that, because the plate  28  faces a downwardly-facing surface of the wafer W, the components shown in  FIG. 3  are on the lower surface of plate  28  and the components shown in  FIG. 4  are on the upper surface. Other components of the preceding embodiment, e.g. the stationary magnet and surrounding process chamber, are omitted for ease of reference. 
         [0050]    While the present invention has been described in connection with various preferred embodiments thereof, it is to be understood that those embodiments are provided merely to illustrate the invention, and that the invention is not limited to those embodiments, but rather includes that which is encompassed by the true scope and spirit of the appended claims.