Abstract:
A circuit board carrier and method of using the same. The carrier allows circuit boards to be processed on lead frame-based semiconductor processing equipment. The circuit board carrier contains a structure to secure a circuit board thereto and the carrier is sized and shaped and provided with standardized indexing holes to allow processing of circuit boards on processing equipment configured for lead frame-based processing.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of application Ser. No. 09/421,164, filed Oct. 19, 1999, now U.S. Pat. No. 6,158,595, issued Dec. 12, 2000, which is a continuation of application Ser. No. 09/225,277, filed Jan. 5, 1999, now U.S. Pat. No. 5,992,649, issued Nov. 30, 1999, which is a continuation of application Ser. No. 08/640,147, filed Apr. 30, 1996, now U.S. Pat. No. 5,911,329, issued Jun. 15, 1999. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to an apparatus and method for facilitating circuit board processing and, more specifically, to a reusable circuit board carrier and method of using same that allows circuit boards to be processed on conventional semiconductor device assembly equipment commonly employed with lead frames. 
     2. State of the Art 
     The manufacture of packaged semiconductor devices is a most competitive, high volume industry. Because of its voluminous production nature, even minute improvements in manufacturing efficiency and/or quality can make a considerable difference in overall manufacturing costs when accumulated over hundreds of thousands or even millions of units. Thus, automation of every manufacturing process is essential for one in the industry to compete, and improving those automated processes to make them more efficient and produce fewer defects is necessary to stay competitive. 
     Automation requires large capital expenditures in automated manufacturing and processing equipment. Moreover, such automated equipment is typically configured to process a specific component or component type having a particular standardized configuration, usually to the exclusion of other types of components. For example, dedicated equipment is purchased for fabrication of packaged semiconductor devices wherein a semiconductor die is mounted to a lead frame, wire-bonded thereto, encapsulated by transfer molding and then trimmed and formed to remove mold flashing and extraneous lead frame strip elements and form the external ends of the lead frame leads. Adaptability of at least some of such equipment, however, to accommodate another type of assembly, such as a printed circuit board assembly, would increase the value of the capital investment by providing greater opportunity for use and manufacturing flexibility. 
     One way to increase efficiency in the manufacturing of semiconductor devices is to process the devices in batches. Batch processing allows a group of components to be indexed through a given process station in greater numbers compared to throughputting single components, and results in more efficient utilization of the processing equipment. Thus, processing equipment is typically configured to perform one or more operations on a number of devices in a single cycle, creating faster processing cycle times and a lower cost per unit. 
     In order to accommodate batch processing in the manufacturing of packaged semiconductor devices, it is known in the art to form several similar components together as a unit for processing. For example, lead frames are typically formed as a linear lead frame strip comprised of several lead frames joined together at their peripheries. Thus, all of the lead frames in a lead frame strip can be substantially simultaneously processed by the addition of dice, subsequent wire bonding, and finally encapsulation to form several packaged semiconductor devices, which are separated in a final trim and form operation, as previously described. 
     Lead frame strips commonly employ relatively robust longitudinal rail segments along each edge to stiffen the strip and provide indexing holes for manipulation of the strip within and between processing stations. Lead frames may also be provided with a carrier that not only provides structural support for the lead frame strip during processing, but is adapted to be indexable and/or conveyable by the manufacturing equipment. For example, in U.S. Pat. No. 5,111,935, a universal lead frame carrier is disclosed to hold individual strips of lead frames together with their respective chips for bonding. The lead frame carrier can then be used to systematically move the lead frame from station to station during manufacture. U.S. Pat. No. 4,554,404 discloses another lead frame support. Magazines, such as disclosed in U.S. Pat. No. 4,910,886, may be employed to transport or store a large number of lead frame strips, with or without carriers. 
     Because of the advantages of batch processing and workpiece handling techniques employed in the manufacture of packaged semiconductor devices and, more particularly, to the processing of lead frame-based devices, such processing would also be beneficial in the manufacture of devices using printed circuit boards or other conductive trace-carrying substrates to which semiconductor dice are mounted and electrically connected. Conventional equipment used in the processing of packaged semiconductor devices, however, is typically configured to accommodate lead frame strips and/or packaged semiconductor devices based upon lead frames and is, therefore, not employable in the manufacture of printed circuit board assemblies and the like. Such equipment used in the manufacture of lead frame-based semiconductor devices (e.g., die attachers, wire bonders, drop dispensers and various lead frame magazines) would, however, be useful for the processing of printed circuit boards and other planar die supports, such as ceramic substrates, if a means could be formed to do so. Moreover, utilization of assembly equipment for more than one type of product would significantly reduce capital expenditures necessary for semiconductor manufacturing of different types of assemblies. 
     Different approaches have been employed for handling printed circuit boards, as disclosed in U.S. Pat. Nos. 3,915,307; 3,930,644; 4,109,379; 4,155,447; 4,198,024; 4,291,867; 4,385,781; 4,600,231; 4,763,782; 4,953,061; 5,339,221; 5,406,455; and 5,456,402. However, the foregoing patents are largely directed toward storage or transport of boards, in most instances are directed toward boards of substantial size, such as mother boards, are intended for installation of boards in chassis or other higher-level packaging for operational purposes, or are not adaptable to automated handling on a high-volume basis. 
     U.S. Pat. No. 5,044,615 discloses a printed circuit board holder adapted to retain a plurality of boards with a cam-type mechanism interposed between boards located in laterally and longitudinally adjacent recesses in the holder. The holder is not suitable in size or configuration for use with lead frame assembly processing and transport equipment, and may not provide the close locational tolerances necessary for use of die-attach and wirebonding equipment. 
     Thus, it would be advantageous to provide a reusable circuit board carrier and method of using same that allows circuit boards to be processed on conventional lead frame-based semiconductor device assembly equipment. 
     BRIEF SUMMARY OF THE INVENTION 
     According to the present invention, a reusable circuit board carrier and method of using same is provided to allow circuit boards to be processed on conventional lead frame-based semiconductor device assembly equipment. More specifically, the circuit board carrier provides structure for temporarily aligning and securing a circuit board thereto for handling, storage and processing and allows the circuit board to be removed and replaced by another circuit board after processing has been completed. Moreover, the circuit board carrier may accommodate one or more circuit boards simultaneously in the same manner that multiple lead frames are manipulated together as a lead frame strip. 
     In a preferred embodiment, the circuit board carrier is comprised of an elongate, substantially planar member having a relatively thin cross-section and a generally rectangular perimeter. The circuit board carrier includes one or more board abutment surfaces for aligning at least one circuit board relative to the carrier, as well as structure for immobilizing and holding the aligned circuit board relative to the carrier. The abutment surfaces may include protrusions extending from the attachment surface of the circuit board carrier, the protrusions having various configurations for abutting flat or contoured edge surfaces of the circuit board. In addition, the immobilizing structure may include protrusions that extend from the attachment surface over a portion of the attached circuit board, or capture pins that fit through apertures in the circuit board and the attachment surface to pin the board to the carrier. Biased abutment surfaces that retract to allow insertion of a circuit board onto the carrier and then return to their original position once the circuit board is inserted may also be incorporated. 
     The carrier of the invention is sized and shaped to be transported between and processed on conventional semiconductor device assembly equipment and may include longitudinally extending lateral flanges along its outer edges. In addition, one or both of these flanges may include indexing holes formed therein to be engaged by transport and indexing devices. The carrier may also include an isolation member comprised of a relatively thin, substantially rectangular sheet of material, such as a static dissipative material or other suitable material known in the art, to isolate the circuit board from the carrier. 
     In another preferred embodiment, the circuit board carrier is comprised of two substantially parallel, elongate rails, each having grooves formed therein for holding one or more circuit boards. The circuit board carrier is provided with structure to keep the circuit board or boards from sliding out of the grooves, such as a transverse member having an interference fit with the grooves or otherwise secured to the rails (pin, screw, snap-fit, etc.) or a pivotally mounted member securable at its free end to the opposite rail. The circuit board carrier is sized and shaped to present circuit boards to be processed on conventional lead frame-based semiconductor device assembly equipment and may include indexing holes along the outer edge of one or both elongate rails to accommodate typical indexing equipment. The circuit board carrier includes at least one cross-member for connecting the two rails together, which may be positioned at an end of the rails to accommodate one or more circuit boards slid into the carrier, or proximate a medial portion of the rails so that one or more circuit boards may be carried on either side of the cross-member. 
     As used in the description of the present invention and specifically in the claims appended hereto, the term “circuit board” is not limited to particular structures such as conventional FR4 boards, but encompasses any conductor-carrying, substantially planar substrate or other die support member formed of any suitable material, including without limitation conductor-carrying laminates formed of various materials, silicon or glass substrates with deposited (as by photolithography) conductors, ceramic substrates and other suitable conductor carriers as known in the art. Further, the term circuit board includes and encompasses all types of single- and multi-die assemblies, such as multi-chip modules (MCMs) including different types of dice or the same die type, the latter being exemplified by single in-line memory modules (SIMM&#39;s) or dual in-line memory modules (DIMMs). 
     Although the circuit board carrier of the present invention has been described in relation to several preferred embodiments, it is believed that a major aspect of the invention is that the circuit board carrier allows circuit boards to be processed on conventional lead frame-based semiconductor device assembly equipment. This and other features of the present invention will become apparent from the following detailed description, the accompanying drawings, and the appended claims. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     FIG. 1 is an exploded, perspective view of a first embodiment of a circuit board carrier in accordance with the present invention; 
     FIG. 2 is a close-up exploded schematic view of a capture pin and associated circuit board carrier of the embodiment of FIG. 1; 
     FIG. 3 is a perspective view of the embodiment of the circuit board carrier of FIG. 1 in assembled form; 
     FIGS. 4A and 4B are top and side schematic views, respectively, of a second embodiment of a circuit board carrier in accordance with the present invention; 
     FIGS. 5A and 5B are top and side schematic views, respectively, of a third embodiment of a circuit board carrier in accordance with the present invention; 
     FIG. 6 is a top schematic view of a fourth embodiment of a circuit board carrier in accordance with the present invention; and 
     FIG. 7 is a top schematic view of a fifth embodiment of a circuit board carrier in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 shows a circuit board carrier  10  in an exploded perspective view, circuit board carrier  10  being generally comprised of an elongate, substantially planar member  12  defining an attachment surface  14 . The planar member  12  has a generally rectangular configuration and is sized to be indexed through conventional lead frame-based semiconductor device assembly equipment, as known in the art. Extending longitudinally along the outer edges  16  and  18  of the planar member  12  are two substantially parallel flanges  20  and  22 , respectively. One or both of the flanges  20  and  22  may be provided with a plurality of indexing or tooling holes  24 . Such tooling holes  24  are used in the art for workpiece transport purposes and to position components within an assembly apparatus. It is preferred that flanges  20  and  22  be formed of a rigid, dimensionally stable material such as spring steel, for example, of 0.010″ thickness. This is due to the fact that commonly employed circuit board materials such as FR 4  are neither dimensionally stable nor robust enough to accommodate transport and indexing equipment without alignment problems and potential damage to the unit. Moreover, the separately formed flanges are easily replaceable if worn or damaged, so that an entire carrier need not be scrapped. The flanges may be mechanically or adhesively secured to the main body of the circuit board carrier  10 , as in laterally extending grooves cut or otherwise formed in the sides of planar member  12 . Further, the flanges  20  and  22  might be provided with board position indicators such as notches  25  (broken lines), holes  27  of a different shape than indexing or tooling holes  24 , or segments  29  of a different material detectable by a proximity sensor so that the presence and exact location of a particular board (especially useful on a multi-board carrier) is easily determinable by the wire bonder, die-attach equipment, or other processing apparatus. 
     Circuit board carrier  10  may be of any suitable length to carry more than one circuit board, the ultimate length thereof being dictated by the longest lead fame strip the storage, transport and processing equipment employed with the carrier is designed to accommodate (generally under ten (10) inches or 25.40 cm.). Similarly, the width of circuit board carrier  10  is also dictated by existing equipment and is generally, therefore, under two (2) inches (5.08 cm.), the same as a large lead frame strip. 
     The planar member  12  includes a plurality of board abutment protrusions  26 ,  28 ,  30 ,  32 , and  34  extending from the attachment surface  14 , protrusions  26 ,  30 ,  32  (see FIG. 3) and  34  having a generally rectangular configuration and protrusion  28  having a contoured cross-section to fit a like-contoured edge  36  of a circuit board  38 . The side abutment surfaces of protrusions  26 ,  28 ,  30 ,  32 , and  34  are used to align and maintain the circuit board  38  in exact or precise position relative to the planar member  12 . 
     An exemplary circuit board  38  as schematically shown includes two apertures  40  and  42  proximate its respective ends  44  and  46 . The planar member  12  also includes apertures  48  and  50  sized, shaped and positioned to be in substantial alignment with the apertures  40  and  42  of the circuit board  38  when the circuit board  38  is properly positioned on the attachment surface  14 . The planar member  12  may also include openings  52  and  54  for access to the underside of the circuit board  38 . 
     An isolation member  56  of a dielectric, preferably static-dissipative material as known in the art, sized and shaped to fit between the circuit board  38  and the planar member  12  may also be included in conjunction with the circuit board carrier  10  to isolate the circuit board  38  from the planar member  12 . The isolation member  56  also includes apertures  58  and  60  positioned to align with apertures  40  and  42 . 
     To assemble the circuit board carrier  10  with an attached circuit board  38 , the isolation member  56  is placed on the attachment surface  14  followed by the circuit board  38  such that the isolation member  56  and the circuit board  38  abut the protrusions  26 ,  28 ,  30 ,  32 , and  34 . As such, the apertures  42 ,  60  and  50  should be in alignment, as should apertures  40 ,  58 , and  48 . Capture pin  62  is then inserted into apertures  42 ,  60  and  50  and capture pin  64  inserted into apertures  40 ,  58 , and  48  to hold the circuit board  38 , isolation member  56  and planar member  12  together. 
     As better shown in FIG. 2, the capture pin  64  (which is substantially the same as capture pin  62 ) includes a cap portion  66  at its proximal end  67 , a first substantially semicylindrical member  68 , and a second substantially semi-cylindrical member  70  extending from the bottom surface  71  of the cap portion  66 . Members  68  and  70  are separated by a diametrically extending compression gap  69 . Half-frustoconical protrusions  72  and  74  at the distal end of the capture pin  64  extend from the semi-cylindrical members  68  and  70 , respectively, but have a slightly larger diameter to provide retaining upper edges  76  and  78 , respectively, for abutting downwardly facing annular shoulder  80  in the countersunk base of aperture  48 . The first and second substantially semi-cylindrical members  68  and  70  extend a distance D equal to the combined thickness T 1  of the circuit board  38 , plus the thickness T 2  of the isolation member  56 , plus the thickness T 3  of the portion of the planar member  12  grasped by the half-fustoconical protrusions  72  and  74 . Thus, when the circuit board carrier  10  is assembled, entry of the half-frustoconical protrusions  72  and  74  into aperture  48  squeezes the substantially semi-cylindrical members  68  and  70  together to close compression gap  69  until the protrusions  72  and  74  extend into the counterbore of aperture  48  and upper edges  76  and  78  engage the shoulder  80 . The protrusions  72  and  74  fit wholly within the aperture  48  and do not extend below the bottom surface  82  of the planar member  12 . 
     FIG. 3 shows the circuit board carrier  10  in assembled form with circuit board  38  in place. As illustrated, the one end  84  of the circuit board  38  abuts the carrier protrusion  26 , the contoured edge  36  is abutted by the carrier protrusion  28 , the other end  84  is abutted by carrier protrusion  30 , and the side  86  is abutted by protrusions  32  and  34 . Moreover, the circuit board  38  is securely attached to the planar member  12  by capture pins  62  and  64 , permitting partial or complete inversion of the assembly as desired or required for transport, storage or processing. 
     The circuit board carrier  100  illustrated in FIGS. 4A and 4B is similar to the previously described embodiment, except that a circuit board, such as circuit board  38 , may be held in position by inverted L-shaped protrusions  102  and  104  and biased protrusions  106  and  108 . The inverted L-shaped protrusions  102  and  104  extend transversely across the top surface  110  of the elongate, substantially planar member  112  to laterally position a circuit board  38  on the planar member  112  within the grooves  114  and  116  formed between the L-shaped protrusions  102  and  104  and the top surface  110 . The biased protrusions  106  and  108  extend upwardly from the top surface  110  and are biased by leaf-type biasing members  118  and  120 . The biasing members  118  and  120  are positioned in cut-outs  122  and  124  and attached at their proximal ends  126  and  128  in a cantilevered fashion to the planar member  112 . As shown, biasing members  118  and  120  may be formed integrally with planar member  112 , and of a reduced thickness in comparison thereto on one or both sides of member planar  112  to enhance resiliency. Thus, to secure a circuit board to the circuit board carrier  100 , the protrusions  106  and  108  are depressed to allow lateral passage of the circuit board  38 . The circuit board  38  is then slid into the grooves  114  and  116  until contacted by the protrusion  130  and protrusions  106  and  108  are then allowed to return to their original positions. As with the previously discussed embodiment, the circuit board carrier  100  has the ability to be used for processing circuit boards in conventional lead frame-based semiconductor device assembly equipment. It is also possible to use straight-sided protrusions at the locations of protrusions  102  and  104  (see broken lines in FIG. 4B) and to hold a circuit board  38  against the vertical surfaces of the fixed protrusions with biased protrusions  106  and  108 . Moreover, rather than using leaf-type biasing members such as  118  and  120 , protrusions such as  106  and  108  might be provided with elastomeric or other (such as coil or bowspring) biasing elements  107  and  109  on their inner faces, so that a circuit board may be dropped between the (straight-sided) protrusions, pushed laterally against biasing elements  107  and  109 , and released, biasing elements  107  and  109  then resiliently aligning circuit board  38  against protrusion  130  and between protrusions at the locations of  102  and  104 . 
     Referring now to FIGS. 5A and 5B, another preferred embodiment of a circuit board carrier  150  is illustrated. The circuit board carrier  150  is generally comprised of two longitudinally extending, substantially parallel elongate rails  152  and  154 . The rails  152  and  154  are held in relative position to one another by a cross-member  153  secured proximate the midpoints of the rails  152  and  154 . As illustrated, the circuit board carrier  150  is designed to hold two circuit boards  38 . Those skilled in the art, however, will recognize that it may be possible to accommodate a single circuit board  38  by moving the cross-member  153  to one end  155  and shortening the lengths of the rails  152  and  154 . Moreover, having rails  152  and  154  as illustrated with the cross-member positioned at one end  155  would allow two circuit boards  38  to be held by the circuit board carrier in a mutually abutted relationship. 
     As better seen in FIG. 5B, each of the rails  152  and  154  has a Y-shaped cross-section including longitudinally extending flanges  156  and  158  forming the tail or base of the Y-shape and extensions  160 ,  162  and  164 ,  166  defining longitudinally extending grooves  168  and  170 , respectively. The grooves  168  and  170  are sized and shaped to receive a circuit board  38  that may be slid therein until abutted by the cross-member  153 . The grooves  168  and  170  hold the circuit board  38  from all movement, other than longitudinal, relative to the circuit board carrier  150 . The flanges  156  and  158  may include a plurality of indexing holes  157  to accommodate processing on conventional semiconductor assembly equipment. 
     In order to keep the circuit boards  38  within the circuit board carrier  150  without becoming dislodged from the rails  152  and  154 , a retaining member  172  may be secured to the ends  155  and  174  of the circuit board carrier  150 . Something as simple as a substantially rectangular bar  172  forming an interference fit between the grooves  168  and  170  at their outer ends and may be used to hold circuit boards  38  against longitudinal movement relative to the carrier  150 . Thus, to secure the circuit boards  38  within the circuit board carrier  150 , one circuit board  38  is slid into one end of the grooves  168  and  170  to abut cross-member  153  on one side thereof, and another circuit board  38  is slid into the other end of the grooves  168  and  170  to abut cross-member  153  on the other side thereof. A retaining member  172  is pressed into each end  155  and  174  of the circuit board carrier  150  and the circuit boards  38  may then be processed through conventional semiconductor assembly equipment. Circuit boards  38  are held in exact longitudinal and lateral alignment for processing, longitudinally through their abutment with cross-member  153 , and laterally by the constraining rails  152  and  154 . It is contemplated that retaining members may be mechanically secured to rails  152  and  154  at  176  by screws, pins or preferably a snap-lock type mechanism using resilient elements for tool-free insertion and removal. Further, the interior (facing cross-member  153 ) edges of retaining members  172  may carry an elastomer strip, a leaf spring, or other biasing element  178  to longitudinally, resiliently maintain circuit boards  38  against cross-member  153 . 
     The circuit board carrier  180  illustrated in FIG. 6 is substantially similar to the circuit board carrier  150  of FIGS. 5A and 5B including Y-shaped elongate rails  182  and  184  and cross-member  187 . The circuit board carrier  180 , however, includes pivotally mounted, elongate retaining members  186  and  188  at the carrier&#39;s ends  190  and  192 , respectively. The retaining members  186  and  188  are pivotally mounted to rotate in the plane of the circuit board carrier at their first ends  194  and  195 , respectively, to the rail  182  by cylindrical pins or protrusions  196  and  197  or other means known in the art. The second ends  198  and  199  of the retaining members  186  and  188  define hooked portions  200  and  202 , respectively. Locking protrusions or pegs  203  and  205  are attached proximate the proximal and distal ends of the rail  184  to engage with and hold the hooked portions  200  and  202  relative to the rail  184  upon inward rotation of the retaining members  186  and  188 , respectively. As the retaining members  186  and  188  are rotated to secure the circuit boards  38 , biasing members  206  and  208 , such as leaf-type springs attached to the retaining members  186  and  188 , respectively, are pressed against the ends  210  and  212  of the circuit boards  38  to force the circuit boards  38  toward the cross-member  187 . The engagement of the hooked portions  200  and  202  with the pegs  203  and  205  sufficiently secures the retaining members  186  and  188  to the rail  184  to withstand the force of the biasing members  206  and  208 . 
     FIG. 7 depicts another alternative circuit board carrier  300  comprised of a substantially planar member  302  having a recess  304  in the upper surface thereof and optional underside recesses  306  to provide access to the back of a circuit board  38  disposed in upper recess  304 . Member  302  includes lateral side rails  308  and  310  extending coplanarly therefrom, side rails  308  and  310  including indexing holes  24 , as previously discussed. Inner lateral surfaces  312  and  314  and inner end surface  316  of recess  304  provide alignment surfaces for circuit board  38 , while bow spring  320  abutting inner end surface  322  ensures longitudinal abutment of circuit board  38  against inner end surface  316 . Retainer clip  324  further ensures circuit board security during inversion, and may be augmented by retention tabs  326  and  328 , if desired, extending over circuit board  38  above inner end surface  316 . Other arrangements might be employed, such as a resilient elastomer strip placed along an end surface such as inner end surface  322  inside recess  304  in combination with deflectable plastic retention tabs or even strips extending over parts of the periphery of recess  304 . Resilient straps such as elastomeric bands may also be placed to extend over portions of the circuit board to which dice are not to be mounted, pulled out of the way during circuit board insertion, and released to retain circuit board  38 . 
     It will be further understood and appreciated by those skilled in the art that the present invention, in addition to permitting use of lead frame handling and processing equipment for circuit boards, also affords advantages in board yield. Specifically, circuit boards are formed in groups on large dielectric panels, such as panels of FR4. In circuit boards which are to be handled and processed using the carriers of the invention, no boundaries or other areas on the panel are required, as the boards are singulated and placed in the carriers. Thus, waste or “Thiefage” of panel material is virtually eliminated. Moreover, with certain designs of the inventive carrier wherein substantially the full face of each circuit board is exposed (no borders being required for holding or handling), more circuit board “real estate” is available for location of components, circuit traces, and connectors. 
     In the exemplary embodiments, the circuit board carrier, as illustrated, has an elongated, generally rectangular configuration holding one or two circuit boards. Those skilled in the art, however, will appreciate that the size, shape, number of circuit boards held and/or configuration of the carrier may vary to accommodate the type and/or configuration of assembly equipment through which the carrier is indexed, without departing from the scope of the present invention. Moreover, those skilled in the art will appreciate that there may be other means of attaching the circuit board to the carrier including modifications and combinations of the means described herein. It will also be appreciated by one of ordinary skill in the art that one or more features of the illustrated embodiments may be combined with one or more features from another to form yet another combination within the scope of the invention as described and claimed herein. Thus, while certain representative embodiments and details have been shown for purposes of illustrating the invention, it will be apparent to those skilled in the art that various changes in the invention disclosed herein may be made without departing from the scope of the invention, which is defined in the appended claims. For example, while the invention has been described with reference to certain processing equipment, such as wire bonders and die-attach machines, it will be appreciated that the invention may also be employed with die pick-and-place devices and inverters to effectuate flip-chip die placement on circuit boards in the carriers of the invention. Furthermore, flex-circuits comprising conductive traces on a flexible dielectric sheet or film (also called TAB tape for Tape Automated Bonding) may be employed with the invention to electrically connect dice to circuit boards disposed in the carriers.