Patent Document

FIELD OF INVENTION  
       [0001]     The present invention relates to interconnect structures for conductively contacting terminals. Particularly, the present invention relates to interconnect structures of a probe apparatus for testing semiconductor devices.  
       BACKGROUND OF INVENTION  
       [0002]     A conventional probe apparatus for testing semiconductor devices includes a number of interconnect structures for temporarily contacting test terminals of the tested device. As the semiconductor technology advances, the tested devices become increasingly smaller while the number of simultaneously accessed terminals continues to increase. At the same time, commercial competition forces the industry to provide semiconductor testing at ever decreasing cost. To meet these demands, there exists a need for further improvement of probe apparatus.  
         [0003]     A crucial component in a probe apparatus are the interconnect structures that are tightly arrayed within a probe apparatus. The interconnect structures are configured for a reliable electrical contacting during a high number of test cycles. With advancement of semiconductors, interconnect structures become increasingly smaller and tighter arrayed.  
         [0004]     Interconnect structures need to meet several functional criteria. Firstly, they need to be sufficiently flexible and resilient to compensate for positioning discrepancies of test terminals. Secondly, the interconnect structures needs to scratch along the terminal&#39;s surface to remove any eventual insulating oxides and films prior to establishing a conductive contact to the test terminals. This scratching also known in the art as scribing is accomplished by endowing the interconnect structure with an elastic deformation characteristic that results in a relative motion of the interconnect&#39;s end along the test terminal&#39;s surface during an initial positioning. Thirdly, the interconnect structures must be simple in shape and configuration to be cost effectively fabricated in high numbers. Fourthly, the interconnect structures need to be configured for a cost effective assembly in ever increasing numbers and tighter spacing.  
         [0005]     In the prior art, two main designs for interconnect structures have been implemented to address the needs stated above. According to a first design interconnect structures are fabricated as well-known buckling beams made of wire having a round and/or rectangular cross section. Buckling beams are oriented in a certain manner with respect to the tested terminals such that they buckle upon initial contact with the test terminals. The resilient buckling of the beams provides for suspension and scribing. Unfortunately, the buckling beams need to be held at both ends with sufficient lateral space to permit buckling in the middle of the buckling beams. This results in a relative complicate and cost intensive assembly.  
         [0006]     In a second design concept, the interconnect structures are fabricated as spring like features directly on a face of a larger structure of the probe apparatus with which they are rigidly connected. Such larger structure may include a well-known space transformer and/or a well-known printed circuit board [PCB] transformer. During the contacting with the test terminal, the resilient deflection of the interconnect structures is opposed by the larger structure on which the interconnect structures are fabricated and with which they are rigidly connected.  
         [0007]     The advantage of the second design concept is that the interconnect structures need not be held on both ends as is required for the buckling beam probes. Unfortunately, the effort for fabricating spring like interconnect structures directly on the face of a larger structure is relatively high. This is, because for a required contact force between the interconnect structure and the test terminal, the spring type interconnect needs to have a structural strength that is significantly higher than that of a buckling beam. Also, since the deflection of each spring like structure is opposed by the larger structure, each interface between the two of them may be exposed to high stresses. As a result, the interface may need additional structural support. In the prior art, complicated fabrication steps are performed for fabricating spring like interconnect structures. Such fabrication steps include multiple layer depositions and multiple layer shaping operations.  
         [0008]     In the prior art, several problems associated with the fabrication of small scale interconnect structures directly on the face of a larger structure remain unresolved. One problem is to position and transport the miniature structure during its fabrication. A second problem is to precisely position an eventually pre-fabricated structure in its final assembly position on a larger structure. A third problem is to attach the eventually pre-fabricated structure in its final assembly position. The attachment is particularly problematic, where stresses are at a maximum in the attachment interface. The present invention addresses these problems.  
       SUMMARY  
       [0009]     An interconnect assembly combines prefabricated interconnect structures that are attached on terminals of a larger structure. The interconnect assembly is preferably part of a probe apparatus for testing semiconductor devices.  
         [0010]     The interconnect structures are prefabricated preferably from sheet metal. The interconnect structures feature an attachment face with which they are attached to the terminals. The attachment face is part of a base, which also features an access face in close proximity and substantially opposing the attachment face.  
         [0011]     The attachment is accomplished by a separate attachment tool that is brought into contact with the access face through which a bonding energy is excerpted onto the base. The bonding energy is transmitted through the base towards the interface between attachment face and terminal. As a result of the bonding energy, a metallurgical bonding takes place between the terminal and the attachment face. Bonding energy may be excerpted in the well-known forms of thermal, electrical and/or mechanical energy. The metallurgical bonding includes soldering, brazing or welding.  
         [0012]     Laterally protruding from the base is a suspension element with a contacting end on its distal end. The contacting end is configured for an eventual removing of an eventual oxide layer on top of the contact terminal—well-known as scribing. The contacting end is also configured for establishing a conductive contact with the contact terminal while the contacting end is forced against the contact terminal by a spring force of the suspension element.  
         [0013]     The suspension element has a predetermined bending characteristic, which provides for the spring force and the scribing movement on a contact terminal during initial positioning movement of the interconnect assembly relative to the contact terminal.  
         [0014]     During initial fabrication of the interconnect structure prior and during its attachment to the larger structure&#39;s terminal, the interconnect structure is combined and held in a carrier structure. The carrier structure and the interconnect structures are preferably of monolithic sheet metal. Once the attachment is completed, the interconnect structure is separated from the carrier structure in a well-known fashion.  
         [0015]     Various techniques may be utilized for fabricating the interconnect structures. Such fabrication techniques may include, photolithographic etching, stamping, bending, forging, plating, laser machining, electric discharge machining, electron beam machining, surface treating, and heat-treating. The interconnect structures may be arranged on the carrier structure for a multiple simultaneous attachment or for a sequential attachment to a number of attachment terminals.  
         [0016]     The attachment interface between terminal and attachment face may be configured substantially independently from other dimensional constrains like, for example, the suspension element&#39;s shape and/or the suspension elements bending characteristic. This is particularly advantageous for configurations of the interconnect structure in which the spring force results in a high bending momentum within the attachment interface.  
         [0017]     The suspension element may be configured to provide the spring force with substantially constant internal stress over its length. In such configuration and for a required spring force and suspension element material, a maximum deflection is provided with a minimum of suspension element length.  
         [0018]     The suspension element may be further shaped in a backwards-looping fashion such that the contacting end and the attachment interface are substantially centered with respect to the spatial orientation of the spring force. In that fashion, bending momentum in the attachment face may be substantially eliminated.  
         [0019]     The attachment terminals serve firstly to transmit electrical signals from conductive leads onto the interconnect structure. The attachment terminals serve secondly to transmit force and bending momentum that eventually result from thee spring force onto the larger structure. For the second reason, the terminals may be embedded in the larger structure for an increased structural interlocking between the larger structure and the attachment terminal. The increased structural interlocking may reduce an eventual risk of delimitation between the attachment terminal and the larger structure.  
         [0020]     The larger structure may be a well-known space transformer or a well-known printed circuit board [PCB] transformer of the probe apparatus. Interconnect structures may be also attached in different sizes and on opposing faces of a single space transformer. 
     
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0021]      FIG. 1  shows a perspective view of a first embodiment interconnect assembly with a portion of a larger structure.  
         [0022]      FIG. 2  illustrates the interconnect assembly of  FIG. 1  in perspective cut view.  
         [0023]      FIG. 3  depicts a perspective view of an extended portion of the larger structure in a first configuration.  
         [0024]      FIG. 4  shows a portion of a first carrier structure positioned on top of the larger structure of  FIG. 3  for attachment of the interconnect structures held within the first carrier structure.  
         [0025]      FIG. 5  illustrates the first carrier structure and larger structure of  FIG. 3  during a fabrication step in which a first number of interconnect structures are attached to the carrier structure.  
         [0026]      FIG. 6  depicts the first carrier structure and larger structure of  FIG. 3  during a fabrication step in which the first number of interconnect structures are cut off the carrier structure while a second number of interconnect structures is attached to the carrier structure.  
         [0027]      FIG. 7  shows the larger structure of  FIG. 3  populated with interconnect structures of  FIGS. 5 and 6  simultaneously attached to the terminals of the larger structure.  
         [0028]      FIG. 8  illustrates an extended portion of the larger structure in a second configuration partially populated with a number of interconnect structures sequentially attached to some of the terminals of the larger structure.  
         [0029]      FIG. 9  depicts the larger structure of  FIG. 8  with an additional interconnect structure held within a portion of a second carrier structure. The additional interconnect structure is positioned with its base in the vicinity of an unpopulated terminal for a following sequential attachment operation.  
         [0030]      FIG. 10  shows the larger structure of  FIG. 8  with the interconnect structure of  FIG. 9  being attached to the unpopulated terminal of  FIG. 9 .  
         [0031]      FIG. 11  illustrates the larger structure of  FIG. 8  with the attached interconnect structure of  FIG. 10  being cut off from the second carrier structure.  
         [0032]      FIG. 12  shows the larger structure of  FIG. 8  populated with the additional interconnect structure of  FIG. 11 .  
         [0033]      FIG. 13  depicts a perspective view of a second embodiment interconnect assembly with a portion of a larger structure.  
         [0034]      FIG. 14  illustrates a portion of a probe apparatus. 
     
    
     DETAILED DESCRIPTION  
       [0035]     As shown in  FIG. 1  and according to a first embodiment of the invention, an interconnect assembly  1  includes a prefabricated interconnect structure  10  attached to a conductive terminal  22  accessible on a face  21  of the larger structure  20 . Prior to attachment, the interconnect structure  10  is prefabricated with an attachment base  15 , a suspension element  13  and a contacting end  12 . The attachment base  15  has an access face  18  and an attachment face  17  that substantially opposes the access face  18 .  
         [0036]     Rigid connection between the interconnect structure  10  and the attachment terminal  22  is provided by metallurgical bonding in an attachment interface between the attachment face  17  and a terminal face  23 . Metallurgical bonding in context with the present invention includes soldering, brazing and welding. The metallurgical bonding provides a connection that is electrically conductive and structurally substantially rigid opposing at least a bending stress resulting in the attachment interface from an operational spring force at the contacting end  12 . The metallurgical bonding may be established along the entire attachment interface or within region of the attachment interface.  
         [0037]     The attachment interface may be defined in conjunction with well-known particularities of well-known attachment techniques and/or in conjunction with the forces resulting in the interface from the spring force to minimize stress within the regions as may be appreciated by anyone skilled in the art. In the exemplary case of utilizing laser energy as bonding energy for establishing a metallurgical bonding, the attachment interface may include a number of dot like weld points distributed in a suitable fashion between an attachment face  17 ,  117  (see  FIG. 13 ) and a terminal face  22 ,  82  (see  FIG. 8 ). In another exemplary case where sonic energy is utilized as bonding energy for establishing a metallurgical bonding, the attachment interface may include a friction weld area distributed between an attachment face  17 ,  117  and a terminal face  22 ,  82  in accordance with well-known particularities of sonic friction welding.  
         [0038]     The suspension element  13  protrudes from the attachment base  15  adjacent the attachment face  17  and adjacent the access face  18  such that the attachment of the attachment face  17  to the terminal face  23  and an access to the access face  18  are substantially unimpeded. The suspension element  13  has a deformation characteristic resulting in a bending movement  143  in responds to a positioning movement  142  induced to the larger structure  20  relative to a contacting terminal  151 ,  162  (see  FIG. 14 ) while the contacting end  12  is held in a fashion opposing the positioning movement  142 . The bending movement translates into a well-known scribing movement  144  along the contacting terminal&#39;s  151 ,  162  surfaces and a spring force forcing the contacting end  12  towards the contacting terminals  151 ,  162 .  
         [0039]     The spring force in turn causes an internal bending stress along the suspension element  13  as is well-known in the mechanical arts. The suspension element  13  may be configured to provide the spring force with a substantially constant internal bending stress along its length between the base  15  and the contacting end  12 . In such configuration and for a required spring force and suspension element material, a maximum deflection is provided with a minimum length of the suspension element  13 . Constant internal stress may be accomplished by adjusting the cross section of the suspension element  13  along the length of the suspension element  13  as it is well appreciated in the art.  
         [0040]     The main purpose of the interconnect structure  10  is to establish a conductive contact between the attachment terminal  22  and a contact terminal  151 ,  162 . For that purpose, the contacting end  12  is configured for an eventual removing of an oxide layer form the contact terminals  151 ,  162  during the scribing. Configurations of the contacting end  12  may include a sharp edge, a pointed edge, an inverted V-shape terminating in a pointed edge, a tip protruding from a face, or the like. The contacting end  12  may be specially coated, solution treated and/or heat treated for an increased wear resistance and metal-to-metal electrical contact performance.  
         [0041]     The larger structure  20  extends substantially within a assembly plane  24  with a number of terminal faces  23  being preferably parallel and in plane with the assembly plane  24  (see also  FIG. 3 ). At this point it is noted that in context with the present invention, the term “larger structure” defines any structure having at least one attachment terminal  22 ,  82  (see  FIG. 8 ) and having an extension substantially larger than the extension of the attachment terminal  22 ,  82  within the attachment plane  24 ,  84  (see  FIG. 8 ). The interconnect structure  10  is shaped preferably along a contour plane  11  that is preferably about perpendicular to the assembly plane  24 . In the context of the present invention, the contour plane  11  is a plane perpendicular to the attach face  17  and parallel to the scribing movement  144 . The suspension element  13  protrudes in an angle relative to the attachment face  17  such that sufficient clearance is maintained between the suspension element  13  on one side and the larger structure  20  and eventually adjacent interconnect structures  10  on the other side during operational resilient deformation of the suspension element  13  and the contacting end  12 .  
         [0042]     The terminal  22  may be conductively connected to a conductive lead  27  for communicating an electric signal towards and/or away from the interconnect structure  10 . The conductive lead  27  may propagate within the larger structure  10  or on its face  21 . In case the terminal  22  protrudes all through the larger structure  20 , the conductive lead  27  may also be connected to the terminal  22  on an opposite face (not shown) of the larger structure  20 .  
         [0043]     As shown in  FIG. 2 , the terminal  22  may be embedded in the larger structure  20  for an increased structural interlocking between the larger structure  20  and the attachment terminal  22 . Forces and momentum eventually resulting from the spring force are thereby transmitted from the base  15  onto the larger structure  20  with a reduced risk of well-known delamitation between the terminal  22  and the larger structure  20 .  
         [0044]      FIG. 3  depicts a perspective view of an extended portion of the larger structure  20  in a first configuration in which a dependent terminal spacing  28  and  29  are defined by a fabrication spacing  31  and  32 , which will be explained in the following under  FIG. 4 . There, a portion of a first carrier structure  19  is positioned on top of the larger structure  10  as depicted in  FIG. 3 . Each of a number of interconnect structures  10  is connected to the first carrier structure  19  via a cutoff bridge  16 .  
         [0045]     The first carrier structure  19  may be positioned with respect to the larger structure  10  in a well-known fashion. For example, well-known reference holes (not shown) may be placed correspondingly in the larger structure  20  and the first carrier structure  19  such that well-known alignment pins (not shown) snuggly and perpendicularly protruding through the reference holes may align the first carrier structure  19  with respect to the larger structure  20 . In aligned position, each attachment face  17  is placed adjacent and at least partially overlapping a terminal face  23 . Each interconnect structure  10  is fabricated and held within the first carrier structure  19  such that each attachment face  17  is substantially in plane with a fabrication plane  14  of the first carrier structure  19 . Hence, all interconnect structures  10  within the first carrier structure  19  may be brought simultaneous into attachment position by merely positioning the first carrier plate  19  with respect to the larger structure  20 . For that purpose, the terminal spacing  28 ,  29  is selected in correspondence with the fabrication spacing  31 ,  32 . In attachment position, assembly plane  24  and fabrication plane  14  are substantially parallel and substantially coincident.  
         [0046]     The fabrication spacing  31 ,  32  is defined to provide sufficient separation for the fabrication steps of the individual interconnect structures  10 . Fabrication steps of the interconnect structures  10  include a partial separation and contouring of an interconnect structure blank, shaping of the interconnect structure blank and eventual finishing operations. The fabrication spacing  31 ,  32  is further influenced by a required minimum stiffness of the first carrier structure  19 . The minimum stiffness may be defined for handling the first carrier structure  19  between fabrication steps and/or for positioning the first carrier structure  19  onto the larger structure  20 .  
         [0047]     Partial separation may be accomplished with well-known techniques such as photolithographic etching, stamping, laser cutting, plasma cutting and the like. Shaping may be accomplished by well-known techniques such as bending, forging, deep-drawing and the like. Finishing operations may include coating, surface finishing, contour finishing, solution treatment, and heat treatment. Fabrication steps may be performed simultaneously and/or sequentially.  
         [0048]     The simultaneously positioned interconnect structures  10  may be simultaneously attached by a number of attachment tools  50 . In such case, the attachment tools  50  may be spaced apart in accordance with the spacing of the access faces  18  within the first carrier structure  19 . Each attachment tool  50  is configured to excerpt a bonding energy via the access face  18  through the base  15  onto the attachment face  17  and the terminal face  23 . The bonding energy is of well-known nature to cause a heating of and/or between the attachment face  17  and the terminal face  23  to a level, where metallurgical bonding in the interface between attachment face  17  and the terminal face  23  occurs. Bonding energy may include thermal energy, electrical energy and/or mechanical energy. Correspondingly, the attachment tool  50  may be part of a soldering apparatus, a laser welding apparatus, an electrical welding apparatus, or a friction welding apparatus. Soldering, bracing or welding may accomplish metallurgical bonding between the attachment face  17  and the terminal face  23 . Metallurgical bonding may be further accomplished without use of an attachment tool like, for example with well-known fabrication techniques in which the terminal faces  23  and the attachment faces  17  are immersed in a liquid solder bath.  
         [0049]     Following the attachment operation, the interconnect structures  10  may be separated from the first carrier structure  19 . As illustrated in  FIG. 6 , a number of cutoff tools  60  may simultaneously cut through a number of cutoff bridges  16 . Well-known electric pulse melting, laser cutting and so forth may accomplish the cutoff operation. The cutoff operation is preferably performed in a fashion that avoids or minimizes debris.  
         [0050]     Separation may be further accomplished by temporarily fully separating the interconnect structure  10  from the first carrier structure  19  followed by press fitting the interconnect structure  10  back into a friction based fit within the first carrier structure  19 . In that fashion, the interconnect structure  10  may be finally separated from the first carrier structure  10  by merely pressing it out of its press fit. The attachment tool  50  may be utilized for pressing the interconnect structure  10  out of its press fit.  
         [0051]     As shown in  FIG. 7 , a final interconnect assembly  1  according to the first configuration features interconnect structures  10  simultaneously attached to the terminals  22  with a spacing substantially equal to the fabrication spacing  31 ,  32 .  
         [0052]      FIGS. 8-12  show a second configuration of the interconnect assembly  2  and its fabrication steps in which the interconnect structures  10  are sequentially assembled with an assembly spacing  41 ,  42  that is substantially independent from fabrication spacing  31 ,  32 . According to  FIG. 8 , a larger structure  80  has a number of attachment terminals  82  arrayed on the larger structure  80  with spacing  41 ,  42 . A number of interconnect structures  10  are attached to the terminal faces  83 . The interconnect assembly  2  is shown in  FIG. 8  in an intermediate fabrication state to illustrate the differences to the interconnect assembly  1 . A final interconnect assembly  2  may feature interconnect structures  10  attached to each of the attachment terminals  82 .  
         [0053]     The sequential attachment is explained in the following for a single interconnect structure  10 .  FIG. 9  depicts a fabrication step in which an interconnect structure  90  is brought with its attachment face  17  into proximity of an unpopulated terminal face  83 . The interconnect structure  90  is held within a second carrier structure  90  such that the positioning of the interconnect structure  90  is unimpeded by prior attached interconnect structures  10  that are already part of the interconnect assembly  2 . The fabrication position of the interconnect structure  90  within the second carrier structure  99  is defined in a fashion that takes into account the spatial limitation at the attachment position of the interconnect structure  90 . This is an important fact for selecting the spacing  41 ,  42  and/or selecting an assembly orientation of the interconnect structures  10  independently from the fabrication spacing  31 ,  32  and independently from an eventual fabrication orientation of the interconnect structure  90  within the second carrier structure  99 .  
         [0054]     As shown in  FIG. 9 , the fabrication position of the interconnect structure  90  is selected such that the second carrier structure  99  remains sufficiently above the interconnect structures  10  while the attachment face  17  is brought into attachment position. To accomplish this, the cutoff bridge  16  holds the interconnect structure  90  at its contacting tip  12 . As it may be appreciated by anyone skilled in the art, the cutoff bridge  16  may be placed at any location suitable for  6 fabrication of the interconnect structure  10 ,  90  and for positioning the attachment face  17  with respect to the terminal face  23 ,  83 .  
         [0055]     In a following step illustrated in  FIG. 10 , the interconnect structure  90  is attached to the unpopulated terminal  83  by the attachment tool  50  in a fashion similar as described for the interconnect assembly  1 . The attachment tool  50  may also operate to push onto the access face  18  such that an eventual gap remaining after initial attachment positioning between the attachment face  18  and the terminal face  83  is closed. The resilience of the suspension element  13  may assist thereby to absorb for the resulting offset between the base  15  and the carrier structure  99 .  
         [0056]     After attachment, the interconnect structure  90  is separated by the cutoff tool  60  in a fashion similar to that explained for the interconnect assembly  1 . In the case, where the attachment face  18  was forced into contact with the terminal face  83  by the attachment tool  50 , the internal stress of the suspension element  13  is released as soon as the cutoff operation is completed. Consequently, the cutoff interconnect structure  90  bounces back into its original fabrication shape as is depicted in  FIG. 12 . For the purpose of visibility, the interconnect structure  90  is hatched in  FIG. 12 .  
         [0057]     Whereas in the first configuration, the interconnect structures  10  are simultaneously attached, in the second configuration the interconnect structures  10  are sequentially attached. The teachings separately presented for the interconnect assembly  1 ,  2  may be combined in ways that are well appreciated by anyone skilled in the art. Hence, the scope of the invention includes embodiments in which sequential and parallel attachment may be combined to optimize the fabrication process in conjunction with particularities of the interconnect assembly  1 ,  2 . For example, an interconnect assembly  1 ,  2  may feature a number of distinctly oriented and grouped interconnect structures  10  for contacting a single contact terminal  151 ,  162 , with a number of contacting ends  12 . In such a case, sequential attachment may be split into groups of equally oriented interconnect structures  10 . A larger structure  20 ,  80  may be consequently populated by a sequential repetition of simultaneous attachment of groups of equally oriented interconnect structures  10 .  
         [0058]      FIG. 13  depicts another embodiment of an interconnect assembly, in which an interconnect structure  110  has a backwards looping suspension element  113  that positions the contacting end  112  substantially centrally together with the attachment face  117  in direction of the positioning movement  142 . In that fashion, the attachment interface is kept substantially free of bending stress regardless of the spring force.  
         [0059]      FIG. 14  illustrates a portion of a probe apparatus  140  in testing position after positioning movement  142  towards a tested circuit chip  160 . The larger structure  20 / 80  is a well-known space transformer with interconnect structures  10  attached on top and bottom. The interconnect structures  10  that are attached on the bottom contact the test terminals  162  of the tested chip  160 . The interconnect structures  10  attached on the top of the space transformer  20 / 80  are in contact with terminals  151  of a well-known printed circuit board [PCB] transformer  150 . Nevertheless, interconnect structures  10  may also be attached to the PCB transformer contacting terminals (not shown) on the space transformer  20 / 80 .  
         [0060]     Carrier plates  19 ,  99  as well as interconnect structures  10 ,  100  are preferably fabricated from sheet metal. The sheet metal is preferably monolithic. In other embodiments, the raw material from which the interconnect structures  10 ,  110  are fabricated is a sandwiched compound material including a number of layers specifically configured for their final placement in one or more elements of the interconnect structure  10 ,  110 . Layers may be selectively removed in well-known fabrication techniques.  
         [0061]     The carrier structures  19 ,  99  are sacrificial and disposed of after attachment of the interconnect structures  10 ,  90 ,  100  to the attachment terminals  22 ,  82  and after completion of the cut off operation. The carrier structures  19 ,  99  may be configured as substantially finite elements containing a certain number of interconnect structures  10 ,  90 ,  100 . The carrier structures  19 ,  99  may also be substantially infinite elements configured as a band continuously forwarded as interconnect structure(s)  10 ,  90 ,  100  are used up during the assembly procedure. The term “substantially finite” means in context with the present invention a limited area extension selected primarily for a feasible handling of a single carrier structure  19 ,  99  within and during the assembly process of the interconnect structures  10 ,  90 ,  100 . The term “substantially infinite” means in context with the present invention a band like configuration in which the length of the band is limited primarily by feasibility of handling outside the assembly process as is well appreciated by anyone skilled in the art.  
         [0062]     A first fabrication apparatus may prefabricate the interconnect structures  10 ,  90 ,  100  in a continuous fashion as is well known for progressive dies. Such fabrication apparatus may be combined with a second fabrication apparatus for positioning and metallurgical bonding the interconnect structures  10 ,  90 ,  100  as explained above. The second fabrication apparatus may be configured in a way similar to a well-known tape application bonding apparatus. For an infinite carrier structure, an interconnect assembly may be fabricated by merely providing a roll of sheet metal band on which the interconnect structures  10 ,  90 ,  100  are prefabricated immediately prior their final assembly. The infinite carrier structure progresses thereby through a number of prefabrication stages in a rate that corresponds to the rate with which the interconnect structures  10 ,  90 ,  100  are attached to the attachment terminals  22 ,  82 .  
         [0063]     Accordingly, the scope of the invention described in the specification above is set forth in the following claims and their legal equivalent:

Technology Category: g