Patent Abstract:
In one aspect, the invention includes a method of forming integrated circuit packages. A base having a plurality of pins extending upwardly therefrom is provided. A support is provided over the base. The support has an upper surface and a plurality of holes extending therethrough. The pins extend through the holes and upwardly beyond the upper surface of the support. An actuator is provided beneath the support. A board having a plurality of integrated circuits bonded thereto is provided. The integrated circuits form a repeating pattern of integrated circuit packages across the board, and the board has a plurality of holes extending through it. The board is placed over the support upper surface with the pins extending into the holes in the board. While the board is over the support upper surface, it is cut to separate the integrated circuit packages from one another. After the cutting, the support is vertically displaced by the actuator to lift the support off the pins. 
     In another aspect, the invention encompasses an integrated circuit package separator for separating integrated circuit packages from a board.

Full Description:
TECHNICAL FIELD 
     The invention pertains to methods of forming integrated circuit packages, as well as to devices for separating integrated circuit packages. 
     BACKGROUND OF THE INVENTION 
     Circuit constructions having integrated circuit (IC) chips bonded to circuit boards (such as SIMMs and DIMMs) can be fabricated by joining IC chips on a single large circuit board comprising a plurality of the constructions. The circuit board can be subsequently cut to separate discrete constructions from one another. The discrete constructions are referred to herein as integrated circuit packages. The smaller the individual circuit packages, the more likely it is for industry processing to utilize the above-described method of forming the packages on a single large board and subsequently cutting individual packages from the board. 
     An exemplary prior art process of separating integrated circuit packages is described with reference to FIG.  1 . FIG. 1 illustrates a board assembly  10  having a plurality of IC chips  12  (only some of which are labeled) bonded thereto. Chips  12  are aligned into individual IC package configurations  14  (only some of which are labeled) to form a repeating pattern of integrated circuit packages  14  across the board assembly  10 . Dashed lines  16  are shown to illustrate the boundaries between individual IC packages  14 . In the shown exemplary embodiment, assembly  10  comprises three separate circuit boards  11 ,  13  and  15 . The number and size of individual circuit boards can vary depending on the number and size of IC packages that are ultimately to be formed. 
     Each of boards  11 ,  13  and  15  comprises a pair of lateral waste sections  21 ,  23  and  25 , respectively. The lateral waste sections  21 ,  23  and  25  are separated from the remainder of boards  11 ,  13  and  15 , respectively, by imaginary dashed lines  20 ,  22  and  24 . In further processing, the individual IC packages  14  are separated from one another by cutting through boards  11 ,  13  and  15  along the regions illustrated by dashed lines  16 . During the cutting to separate IC packages  14  from one another, boards  11 ,  13  and  15  are also cut along regions illustrated by dashed lines  20 ,  22  and  24  to remove waste portions  21 ,  23  and  25  from the lateral sides of the boards, and accordingly from lateral edges of the ultimately formed IC packages. 
     Orifices  19  (only some of which are labeled) are provided throughout circuit boards  11 ,  13  and  15 . Specifically, pairs of orifices  19  are provided in each IC package  14 , and at least two orifices  19  are provided in each of waste portions  21 ,  23  and  25 . 
     FIG. 1 further illustrates an IC package separator  40  comprising a cutting mechanism  42  (shown schematically as a cutting wheel, although other cutting mechanisms, such as, for example, router bits or linear blades, are known to persons of ordinary skill in the art), a retaining table  44 , and a control mechanism  45  configured to control orientation of cutting wheel  42  relative to table  44 . Retaining table  44  can comprise, for example, an x-y table (i.e., a table horizontally adjustable in x and y directions; an “X”, “Y” and “Z” axis system is illustrate in a lower corner of FIG.  1 ). Control mechanism  45  can control the x and y orientation of table  44  and the z (i.e., vertical) orientation of cutting mechanism  42  to precisely cut a board retained on table  44 . Table  44 , cutting mechanism  42 , and control mechanism  45  can be comprised by commercially available cutting systems, such as, for example, Advanced Technology Incorporated&#39;s CM 101  single spindle router (or, more generally, a circuit board depanelization router). 
     FIG. 1 also illustrates that table  44  comprises an upper platform  46 . A subplate  48  is provided over platform  46 , and a stripper plate  50  is provided over subplate  48 . Subplate  48  comprises a plurality of upwardly extending pins  60  (only some of which are labeled), and stripper plate  50  comprises a number of orifices  62  configured to slide over pins  60 . Subplate  48  is retained on table  44  by downwardly extending pins (not shown) which are aligned with and precisely received within orifices (not shown) extending within platform  46  of table  44 . 
     Orifices  19  of boards  11 ,  13  and  15  align with pins  60 . In operation, boards  11 ,  13  and  15  are slid over pins  60  until the pins protrude through orifices  19 . Typically, orifices  19  are only about 0.003 inches wider than pins  60  to insure tight alignment of boards  11 ,  13  and  15  with subplate  48 . After boards  11 ,  13  and  15  are retained on table  44  by pins  60 , cutting mechanism  42  is utilized to cut along the regions illustrated by dashed lines  16 ,  20 ,  22  and  24 . Such cutting separates discrete integrated circuit packages  14  from one another, as well as from waste regions  21 ,  23  and  25 . The separated circuit packages are retained on table  44  by pins  60  extending through the packages. Specifically, each of individual packages  14  comprises a pair of orifices  19  and is thereby retained on table  44  by a pair of pins  60 . 
     After the IC packages are separated from one another, stripper plate  50  is manually lifted off of subplate  42  to lift the IC packages  14  from pins  60 . Once stripper plate  50  is lifted off from pins  60 , the individual IC packages can be separated from stripper plate  50 . An exemplary method of removing the IC packages from stripper plate  50  is to tilt plate  50  and allow the packages to slide off plate  50 . After the packages  14  are removed, plate  50  can be returned to over  48  and used again for separating IC packages. 
     Difficulties can occur in utilizing the assembly of FIG. 1 for separating IC packages. For instance, separated IC packages can be broken as stripper plate  50  is lifted from subplate  48 . It would be desirable to reduce or eliminate such problems. 
     SUMMARY OF THE INVENTION 
     In one aspect, the invention encompasses a method of forming integrated circuit packages. A base having a plurality of pins extending upwardly therefrom is provided. A support is provided over the base. The support has an upper surface and a plurality of holes extending therethrough. The pins extend through the holes and upwardly beyond the upper surface of the support. An actuator is provided beneath the support. A board having a plurality of integrated circuits bonded thereto is provided. The integrated circuits form a repeating pattern of integrated circuit packages across the board, and the board has a plurality of holes extending through it. The board is placed over the support upper surface with the pins extending into the holes in the board. While the board is over the support upper surface, it is cut to separate the integrated circuit packages from one another. After the cutting, the support is vertically displaced by the actuator to lift the support off the pins. 
     In another aspect, the invention encompasses an integrated circuit package separator for separating integrated circuit packages from a board. The board comprises a plurality of integrated circuits bonded thereto, and has a plurality of holes extending within it. The separator includes a base having a plurality of pins extending upwardly therefrom and a support over the base. The support has an upper surface, a plurality of holes extending therethrough, and a pair of opposing ends. The pins extend through the holes in the support and upwardly beyond the upper surface of the support. The support and pins are configured such that the pins extend into the holes in the board when the board is placed over the support upper planar surface. The separator further includes a pair of actuators beneath the support and configured to vertically displace the support and lift the support off the pins. Additionally, the separator includes a cutting mechanism configured to cut the board while the board is over the support upper planar surface and thereby separate the integrated circuit packages from one another. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred embodiments of the invention are described below with reference to the following accompanying drawings. 
     FIG. 1 is a diagrammatic, perspective, exploded view of a prior art IC package separator and circuit board assembly. 
     FIG. 2 is a diagrammatic top view of an IC package separator of the present invention. 
     FIG. 3 is a diagrammatic, perspective, exploded view of an IC package separator of the present invention with a stripper plate of the present invention and a circuit board. 
     FIG. 4 is a view of the FIG. 3 assembly with the circuit board retained on the IC separator. 
     FIG. 5 is a view of the FIG. 4 assembly after the retained circuit board is cut to separate individual IC packages from one another. 
     FIG. 6 is a view of the FIG. 5 assembly after a stripper plate is lifted to release separated IC packages from retaining pins. 
    
    
     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). 
     An IC package separator of the present invention and a method of operation of such separator are described below with reference to FIGS. 2-6. In referring to FIGS. 2-6, similar numbering to that utilized above in describing prior art FIG. 1 will be used, with differences indicated by the suffix “a” or by different numerals. 
     Referring to FIG. 2, a separator  100  of the present invention is shown in top view. Separator  100  comprises a table  44   a  and a subplate  48   a  provided over table  44   a . Table  44   a  can comprise, for example, an x-y table similar to the table  44  described above with reference to FIG.  1 . Subplate  48   a , like the above-described substrate  48  of FIG. 1, can be joined to table  44   a  through a plurality of downwardly extending pins (not shown), and comprises a plurality of upwardly extending pins  60  (only some of which are labeled) configured to retain a circuit board assembly (not shown). 
     Subplate  48   a  differs from subplate  48  of FIG. 1 in that subplate  48   a  comprises notches  102  at its ends. Notches  102  are provided to allow room for a pair of forcer plates  104  and  106  to move vertically (in and out of the page of FIG. 2) relative to table  48   a . Forcer plates  104  and  106  comprise upwardly extending pins  108  and  110 , respectively. Base plate  48   a  comprises an upper planar surface  115 , and forcer plates  104  and  106  comprise upper planar surfaces  117  and  119 , respectively. Upper planar surfaces  115 ,  117  and  119  ultimately support a circuit board assembly (not shown in FIG.  2 ). Planar surfaces  115 ,  117  and  119  are preferably substantially coplanar with one another to avoid distorting (e.g., bending) a supported circuit board assembly. 
     Forcer plates  104  and  106  are connected to actuators  112  and  114 , respectively, configured to vertically displace forcer plates  104  and  106 . In the exemplary shown embodiment, forcer plates  104  and  106  are connected to the actuators with screws  116 . It is to be understood, however, that other mechanisms could be utilized for joining forcer plates  104  and  106  to actuators  112  and  114 , including, for example, welding. 
     Actuators  112  and  114  are pneumatic (preferably air-powered) and connected to a gas source  120 . An advantage of utilizing air powered actuators is that most wafer fabrication plants have a source of clean dry air available. Accordingly, it is relatively convenient to couple air powered actuators  112  and  114  into existing fabrication plants by simply connecting them to existing air lines. However, it is to be understood that the actuators can be powered by other sources besides air, including, for example, other fluids, such as liquids, as well as non-pneumatic and non-hydraulic sources, such as, for example, electricity. 
     Separator apparatus  100  comprises a cutting assembly (not shown in FIG. 2) and a controller (not shown in FIG.  2 ), analogous to the cutting assembly  42  and controller  45  of FIG.  1 . 
     Referring to FIG. 3, IC circuit package separator  100  is shown in exploded view with a circuit board assembly  10  identical to the assembly described above with reference to FIG.  1 . 
     A stripper plate  50   a  is provided between subplate  48   a  and circuit board assembly  10 . Stripper plate  50   a  is similar to the stripper plate  50  of FIG. 1 in that plate  50   a  comprises a plurality of orifices  62  configured for receipt of pins  60 . However, stripper plate  50   a  differs from plate  50  of FIG. 1 in that plate  50   a  also comprises orifices  122  configured for receipt of upwardly extending pins  108  and  110  of forcer plates  104  and  106 . Pins  108  and  110  are preferably tapered pins, such as can be obtained from McMaster-Carr. Exemplary pins have a dimension of 0.248 inches at base, 0.2324 inches at top, and a length of 0.75 inches. The taper of the pins can assist in aligning support  50   a  over the pins during placement of support  50   a  onto base  48   a.    
     Stripper plate  50   a  further differs from plate  50  of FIG. 1 in that plate  50   a  is configured for receipt of a series of panels  132 ,  134  and  136 . Stripper plate  50   a  can comprise, for example, static-reduced plastic having a thickness of greater than {fraction (3/16)} inches, and panels  132 ,  134  and  136  can comprise, for example, aluminum. In the shown embodiment, panels  132 ,  134  and  136  are held to stripper plate  50   a  by a plurality of screws  138  (only some of which are labeled). It will be recognized, however, that other mechanisms can be utilized for holding panels  132 ,  134  and  136  to stripper plate  50   a , including riveting. Alternatively, panels  132 ,  134  and  136  can be molded as part of stripper plate  50   a.    
     Panels  132 ,  134  and  136  comprise ribs  140 ,  142  and  144 , respectively (only some of which are labeled). Ribs  140 ,  142  and  144  can assist in supporting board assembly  10 . Specifically, IC chips  12  are frequently provided on both an upper surface of circuit board assembly  10 , and a bottom surface (not shown). Ribs  140 ,  142  and  144  (also referred to as blocks) have upper surfaces  141 ,  143  and  145 , respectively, which contact the bottom surfaces of circuit boards  11 ,  13  and  15  at locations between the IC chips  12  on the bottom of the board. Preferably, such upper surfaces are provided at a height approximately equal to a thickness of integrated circuit chip components  12 . Accordingly, when boards  11 ,  13  and  15  are rested on panels  132 ,  134  and  136 , respectively, the boards rest on the upper surfaces of blocks  140 ,  142  and  144  while leaving integrated circuit chip components on the underside of boards  11 ,  13  and  15  extending between block upper surfaces  141 ,  143  and  145  and panels  132 ,  134  and  136 . An exemplary block height (or thickness) of blocks  140 ,  142  and  144  for a DRAM having IC chips  12  with a TSOP dimensional package is 0.040 inches ±0.005 inches. As another example, if IC chips  12  have a SOJ dimensional package, the block height is preferably 0.140 inches ±0.005 inches. 
     Blocks  140 ,  142  and  144  can be formed as one piece with panels  132 ,  134  and  136 . Alternatively, blocks  140 ,  142  and  144  can be formed as discrete pieces from panels  132 ,  134  and  136  that are subsequently fastened to the panels. 
     In the shown embodiment, blocks  140 ,  142  and  144  are provided in a one-to-one correspondence with integrated chip packages  14 . Also, in the shown exemplary embodiment each of panels  132 ,  134  and  136  is identical to one another, and in a one-to-one correspondence with individual boards  11 ,  13  and  15 . It is to be understood, however, that the invention encompasses other embodiments (not shown) wherein the blocks are not provided in a one-to-one correspondence with packages  14 , wherein the panels are not identical to one another, and wherein the panels are not in a one-to-one correspondence with the individual boards. 
     Pins  60  extend upwardly beyond upper surfaces  141 ,  143  and  145  of blocks  140 ,  142  and  144 , and are configured to retain circuit board assembly  10  over stripper panel  50   a . In the shown embodiment, pins  60  do not extend through panels  132 ,  134  and  136 . However, it is to be understood that the invention encompasses other embodiments wherein pins  60  do extend through such panels. 
     FIG. 3 shows a side perspective view of actuator  112 . In such view it can be seen that several ports  150 ,  152 ,  153 ,  154   155  and  156  are provided between actuator  112  and gas source  120 . Valves (not shown) are provided between source  120  and one or more of ports  150 ,  152 ,  153 ,  154 ,  155  and  156 . Such valves enable fluid to be selectively flowed from source  120  into one or more of ports  150 ,  152 ,  153 ,  154 ,  155  and  156  to selectively control raising and lowering of forcer plate  104  with actuator  112 . For instance, flow of gas into port  152  can force a pneumatic cylinder to lift forcer plate  104 , and flow of gas into port  150  can force the pneumatic cylinder to lower forcer plate  104 . 
     Ports  154  and  156  are connected to release valves  163  and  165 , respectively, which enable a pressure on at least one side of the pneumatic cylinder of actuator  112  to be maintained at ambient pressure (generally, about 1 atmosphere). Specifically, release valves  163  and  165  comprise outlet ports  157  and  159 , respectively, which vent to a surrounding environment. Persons of ordinary skill in the art will recognize that one or more of ports  150 ,  157  and  159  are utilized as gas outlet ports during lifting of forcer plate  104 , and port  152  comprises a gas inlet port during such lifting. In preferred embodiments of the present invention, the release valves are associated with an outlet side of actuator  112  to enable equilibration of a pressure at such outlet side to ambient prior to (and/or during) lifting of forcer plate  104 . Specifically, the release valves enable gas to be drained from outlet lines (more specifically, the gas is drained through ports  157  and  159  which are open to ambient conditions) prior to, and/or during, lifting with the actuator. Actuator  114  (FIG. 2) is preferably identical to actuator  112  and connected to an identical valve and port assembly as that shown connected to actuator  112 . Accordingly, actuator  114  is also connected with release valves configured to equilibrate a back-pressure of the actuator to ambient prior to, and/or during, lifting of stripper panel  50   a . The equilibration of pressure at the outlet ends of both of actuators  112  and  114  to ambient during a lifting operation can enable both actuators to have an identical back-pressure during the lifting operation. This can facilitate having both actuators lift simultaneously and in unison. Such simultaneous lifting can avoid distortion (such as, for example, bending) of circuit board assembly  10  during the lifting. 
     Stripper plate  50   a  has an upper planar surface  160  and a pair of opposing ends  162  and  164 . Opposing ends  162  and  164  overlie forcer plates  104  and  106 , respectively. In operation, actuators  112  and  114  are utilized to lift opposing ends  162  and  164  simultaneously and in unison. Such can be accomplished by, for example, maintaining approximately equal gas pressure at both of actuators  112  and  114  during lifting, and is found to reduce breakage of integrated circuit packages relative to prior art methods. The term “approximately” in the previous sentence is utilized to indicate the gas pressure at both actuators is equal within operational parameters. 
     A method of operation of separator  100  is described with reference to FIGS. 4-6. In referring to FIGS. 4-6, subplate  48   a  is referred to as a base, and stripper plate  50   a  is referred to as a support. Referring first to FIG. 4, circuit board assembly  10  is shown retained on support  50   a . Specifically, circuit board assembly  10  is placed over support upper surface  160  with pins  60  extending through orifices  19  of the circuit boards  11 ,  13  and  15 . Pins  60  and board assembly  10  are aligned such that each of the integrated circuit packages  14  is retained to the support  50   a  by at least one pin, and, in the shown embodiment, is retained by 2 pins. In the FIG. 4 processing step, actuators  112  and  114  (FIG. 2) are in a lowered position. 
     Referring to FIG. 5, the individual integrated circuit packages  14  are separated from one another by cutting through boards  11 ,  13  and  15 . 
     Referring to FIG. 6, actuators  112  and  114  (FIG. 2) are utilized to vertically displace support  50   a  from base  48   a . Preferably, such vertical displacement comprises lifting both of ends  162  and  164  of support  50   a  substantially simultaneously and substantially in unison with one another. (As used in the preceding sentence, the term “substantially” indicates that the lifting of both ends is simultaneous and in unison within operational parameters.) In exemplary applications the upper surface  160  of support  50   a  is level prior to the lifting and remains level during the lifting. The lifting of support  50   a  releases separated circuit packages  14  from pins  60 . After such release, support  50   a  can be, for example, manually lifted from pins  108  and  110 , and the separated packages removed from support  50   a.    
     In compliance with the statute, the invention has been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the invention is not limited to the specific features shown and described, since the means herein disclosed comprise preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalents.

Technology Classification (CPC): 8