Abstract:
An adapter or housing for a module, such as a single in-line memory module (SIMM) or the like, and method of using the same are disclosed where the SIMM and attached housing fit a predetermined shape SIMM socket. The housing replaces SIMM board material that would otherwise be used to help secure the SIMM to a predetermined shape SIMM socket or connector. The configuration of the housing allows a SIMM or the like to be snapped or slid and secured into the housing. If desired, an adhesive, potting material and other bonding material can be used to secure the SIMM board to the housing and/or pot the SIMM within the housing.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [1]    1. This application is a continuation of application Ser. No. 09/205,872, filed Dec. 4, 1998, which is a divisional of application Ser. No. 08/705,533, filed Aug. 29, 1996, now U.S. Pat. No. 5,892,660 issued Apr. 6, 1999.  
     
    
     
       BACKGROUND OF THE INVENTION  
         [2]    2. 1. Field of the Invention  
           [3]    3. This invention relates generally to modules used in computers, such as single in-line memory modules (SIMMs) and the like. More specifically, the present invention relates to a SIMM housing including a smaller printed circuit board to form a standard outline module.  
           [4]    4. 2. State of the Art  
           [5]    5. An integrated circuit (IC) typically includes a semiconductor die (die) electrically attached to a lead frame providing physical support for the die and connecting the die to external circuitry, such as a printed circuit board. In such an arrangement, the lead frame and die are connected by forming wire bonds between the lead fingers of the lead frame and the bond pads located on a surface of the die. The die and lead frame are then typically encapsulated within a plastic package, although ceramic and metal packages may also be used, depending on the operating environment and the packaging requirements of the die.  
           [6]    6. As the demand for memory, in particular random access memory (RAM), surpassed the memory capability of a single die, multi-chip modules (MCMs) were developed having a number of memory devices attached to a single substrate, such as a printed circuit board. A single in-line memory module (SIMM) is a multi-chip memory module having multiples of the same basic die, where the semiconductor memory chips are aligned in a row and interconnected to a printed circuit board to, in effect, create a single device with the memory capacity of the combined memory chips. Internal circuitry of the printed circuit board connects each chip to terminals attached along one edge of the printed circuit board. The terminals are configured for attachment to an edge-type connector, such as a SIMM socket as is known in the art. As the demand for additional memory on a single device has increased, other devices, such as a dual in-line memory module (DIMM), have also been developed. Such devices, while providing the desired memory capability on a single printed circuit board, are relatively expensive to manufacture, requiring manufacture and/or purchase of relatively expensive components.  
           [7]    7. As an increase in supply of SIMMs in the marketplace has dropped the price of RAM, an even greater need to decrease the cost of manufacturing SIMMs exists. Because of advances in chip manufacturing technology and efficiency, manufacturers can produce thousands of chips per day. With such high volume production rates, small improvements in efficiency and/or cost reduction per chip can make substantial differences in the daily cost of manufacturing. While manufacturers have continued to streamline processes to improve efficiency and decrease production costs, the amount of materials used to form many standard components has remained relatively constant.  
           [8]    8. One of the components of a SIMM is a printed circuit board, typically comprised of a fire-retardant, epoxy resin/glass cloth laminate, commonly referred to as FR-4. The epoxy resin used in the formation of the FR-4 board is typically diglycidyl ether of 4,4′ -bis(hydroxyphenyl) methane, or other low-molecular weight polymers of it. Fire retardancy is imparted by including enough tetrabromobisphenol-A to provide 15% to 20% bromine content. Sometimes, about 10% of higher functionality epoxy is added to raise the glass transition point and improve chemical resistance of the resin by increasing cross-link density.  
           [9]    9. Other materials used in the manufacture of FR-4 boards include curing agents such as dicyandiamide (DICY) and catalysts such as tertiary amines. DICY has low solubility in common organic solvents, so that the full stoichiometric capability for linking the epoxy-bond network is not used. The molding flow is suited for multi-layer laminating needed for printed circuit boards, and the cured physical properties are good with strain to fracture ratio of about 0.04, thereby providing enough resiliency for good metal or glass bond interfaces.  
           [10]    10. While FR-4 is the preferred material for the SIMM board, it is a relatively expensive part of the SIMM and can account for a substantial portion of the cost of the entire SIMM. Other high-performance boards based on such high glass-transition-temperature materials, such as polyamide-glass or cyanate-glass, may also be used, but are substantially more expensive than FR-4. In addition to the cost of materials, the care necessary to ensure an aesthetically pleasing component requires special attention to be paid to the quality of workmanship. This additional care may require more detailed or additional inspection of each component and slow the rate of production.  
           [11]    11. It is known in the art to provide containers for “plug-in” peripheral cards in the form of printed circuit boards contained within an exterior package. These devices are termed “PCMCIA style peripheral devices” (PCMCIA being the acronym for Personal Computer Memory Card International Association) and are designed to be plugged-in and removed by the user. Hence, the cards are typically housed within a metal case that protects the memory devices contained therein from being physically contacted and/or damaged by the user or environment. Such a device is illustrated in U.S. Pat. No. 5,397,857 to Farquhar et al.  
           [12]    12. SIMMs, on the other hand, are not typically housed and, as previously described, are simply printed circuit boards having a row of memory chips attached thereto and a row of connectors along one edge. While typically being removably attached to a computer card, SIMMs tend to remain untouched once installed in a computer unless the amount of memory is changed by adding to or replacing one or more SIMMs.  
           [13]    13. An exception to a conventional SIMM configuration is taught in U.S. Pat. No. 5,109,318 to Funari et al. As described in U.S. Pat. No. 5,109,318, a housing for a conventional SIMM serves as a heat sink. Such a heat sink housing would add to the cost of the finished SIMM.  
           [14]    14. Therefore, a need exists for the fabrication of less costly SIMMs and the like by reducing the quantity of material used to make the SIMM board while allowing the SIMM to be mounted to an industry-standard SIMM socket. In addition, the ability to cover the SIMM and any aesthetic anomalies thereon has the added benefit of speeding the production rate of SIMMs.  
         BRIEF SUMMARY OF THE INVENTION  
         [15]    15. Accordingly, a module, such as a single in-line memory module (SIMM) or the like is provided comprised of a SIMM board and a SIMM holder or adapter configured to mate with a predetermined configuration SIMM socket. The adapter, preferably made of a single-piece molded plastic, houses a reduced-size SIMM board, effectively replacing a portion of the board material with a less-expensive adapter material. Such a SIMM, while compatible with SIMM sockets known in the art, requires less board material and is less expensive to produce than conventional SIMMs.  
           [16]    16. In a preferred embodiment, a module, such as a SIMM holder or adapter, includes two memory board retaining members, each having a substantially longitudinally extending slot sized and shaped to receive and secure a memory board such as a printed circuit board. The retaining members are also configured to be at least partially received within a standard SIMM socket as is known in the art. That is, a portion of each retaining member fits into the SIMM socket to occupy the space that would otherwise be filled by a conventional SIMM board. In other words, the portion of the retaining member that fits in the SIMM socket fills the gap or gaps between the end or ends of the SIMM socket and the reduced-size SIMM board and helps to align the reduced-size SIMM board relative to the socket.  
           [17]    17. In another preferred embodiment, the retaining members are held in relative relation to one another by a cross-member depending from and extending between the retaining members. The cross member preferably includes a longitudinally extending groove or slot sized and shaped to receive the top edge of a module board. Thus, the cross-member and its associated retaining members form a C-shaped adapter that can hold a module board therein.  
           [18]    18. In yet another preferred embodiment, the SIMM socket adapter according to the present invention is in the form of a housing having two retaining members and at least one longitudinally extending wall extending from one retaining member to the other. Such a wall covers at least a portion of the SIMM board and provides structural strength for the adapter. A SIMM board positioned within the housing can be potted as is known in the art. Thus, the need to ensure that the SIMM board and the chips and other components located thereon are aesthetically pleasing is not necessary.  
           [19]    19. In yet another preferred embodiment, the SIMM socket adapter includes two socket connectors attached to and separated by a module housing. The module housing may include only one side wall, in which case at least one protrusion or retaining portion on each side of the board may be needed to secure the board to the adapter, or may include side walls on both sides of the module board, in which case the board becomes essentially “sandwiched” between the two side walls. In either case, the board and any components thereon can be potted by methods known in the art.  
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [20]    20.FIG. 1 is a perspective view of a prior art SIMM;  
         [21]    21.FIG. 2 is a perspective view of a first preferred embodiment of a SIMM adapter according to the present invention;  
         [22]    22.FIGS. 3A and 3B are schematic views of a reduced-size SIMM sized to fit within the SIMM adapter of FIG. 2;  
         [23]    23.FIG. 4 is a perspective view of the SIMM of FIGS. 3A and 3B inserted into the SIMM adapter of FIG. 2.  
         [24]    24.FIG. 5 is a perspective view of a second embodiment of a SIMM adapter according to the present invention;  
         [25]    25.FIGS. 6A and 6B are schematic drawings of a third embodiment of a SIMM adapter according to the present invention;  
         [26]    26.FIG. 7 is a schematic drawing of a fourth embodiment of a SIMM adapter according to the present invention;  
         [27]    27.FIGS. 8A and 8B are schematic drawings of a fifth embodiment of a SIMM adapter according to the present invention;  
         [28]    28.FIG. 9 is a perspective view of a sixth embodiment of a SIMM adapter according to the present invention;  
         [29]    29.FIG. 10 is a perspective view of a seventh embodiment of a SIMM adapter according to the present invention;  
         [30]    30.FIG. 11 is a side view of a general illustration of the SIMM adapter of the present invention connected to another circuit board; and  
         [31]    31.FIG. 12 is a view of a module and module adapter of the present invention in conjunction with a computer.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [32]    32. Referring to FIG. 1, a prior art, single in-line memory module (SIMM)  10  is illustrated and comprised of a module board  12 , typically a printed circuit board, with a plurality of semiconductor devices  14  attached thereto. In a SIMM, each of the semiconductor devices  14  are usually the same type and size and arranged in a row longitudinally across the printed circuit board  12 . The printed circuit board  12  is generally rectangular in shape and has a row of contacts  13  along a bottom edge  15  of the board  12 . The printed circuit board  12  also includes holes  16  and  18  proximate each end  20  and  22  of the board  12 , respectively, and a J-shaped notch  24  on the corner  26  of the board  12  to assist alignment of the contacts  13  with a SIMM socket or connector as is known in the art. As illustrated by dashed lines  28  and  30 , the printed circuit board  12  material, typically FR-4, between the dashed line  28  and the end  20  and between the dashed line  30  and the end  22  is merely used to attach and align the SIMM  10  to a SIMM socket, and could be eliminated from the SIMM  10  without any loss of functionality. In order to properly attach and align the SIMM  10  to an industry standard SIMM socket, however, without the use of the adapter according to the present invention, the portions  17  and  19  of the board  12  extending beyond the lines  28  and  30  are needed.  
         [33]    33. Referring now to FIGS. 2, 3A,  3 B, and  4 , a first preferred embodiment of an adapter or housing  40  according to the present invention is illustrated. The housing  40 , generally a rectangular box shape, is comprised of a first side wall  42  and a second side wall  44  depending from and extending between a first connector or retaining member  46  and a second connector or retaining member  48 . The walls  42  and  44  and the connectors  46  and  48  of the housing  40  form a chamber  41  into which a SIMM  60  or the like can be inserted (see FIGS. 3A and 3B), the walls  42  and  44  being separated a distance sufficient to allow clearance for the SIMM  60  and any chips  66  or components  68  thereon. The walls  42  and  44  may also include holes  43  and  45  and other features of a conventional SIMM  10  so that the housing  40  and the SIMM  60  therein properly fit within a SIMM socket as known in the art.  
         [34]    34. To keep a SIMM  60  or the like securely positioned within the chamber  41 , the connectors  46  and  48  define slots  50  and  52 , respectively, that longitudinally extend along a length of each connector  46  and  48 . The slots  50  and  52  are sized and spaced from one another so that a SIMM board  62  fits snugly therein. In addition, the connectors  46  and  48  include extended portions or tabs  54  and  56 , respectively, that are aligned with and generally the same width as the slots  50  and  52 , and thus generally the same width W as the SIMM board  62 . As shown in FIG. 4, when the SIMM  60  is properly inserted into the housing  40 , the tabs  54  and  56  extend substantially the same distance as the bottom edge  64  of the SIMM  60  so that the end surfaces  55  and  57  of the tabs  54  and  56 , respectively, are substantially flush with the bottom edge  64 . If desired, once the SIMM  60  is properly inserted, any spaces between the SIMM  60  and the inside of the housing  40  could be potted or otherwise filled with a potting or other compound known in the art to ensure that the SIMM  60  remains fixed to the housing  40 .  
         [35]    35. Referring now to FIG. 5, another preferred embodiment of a holder or adapter  70  according to the present invention is illustrated. This embodiment is similar to the housing  40  of FIG. 2 but has only one side wall  72  extending between the end portions or connectors  74  and  76 . Thus, a SIMM such as SIMM  10 , with portions  17  and  19  removed, can be inserted therein with the semiconductor devices  14  facing the inside of the side wall  72 , or inserted with the semiconductor devices  14  being exposed. Preferably, the semiconductor devices  14  face the inside of the side wall  72  so that any aesthetic anomalies on the SIMM  10  are covered by the side wall  72 . In addition, a J-shaped recess  78  may be incorporated in the connector  74  to substantially duplicate the configuration of the SIMM  10  for proper seating of the adapter  70  and SIMM  10  within a conventional SIMM socket. Moreover, as with the housing  40 , any spaces between the SIMM  10  and the inside of the side wall  72  can be potted or otherwise filled with other materials known in the art.  
         [36]    36. To illustrate that the present invention has applicability to various memory modules, the SIMM  60  of FIGS. 3A and 3B is of a different configuration than the SIMM  10  of FIG. 1, SIMM  10  being an older type conventional SIMM and the SIMM  60  being a more current SIMM version. Unlike the SIMM  10  of FIG. 1, however, SIMM  60 , while otherwise having a conventional configuration, does not have the same length L as the conventional SIMM  10 , (i.e., not including the portions  17  and  19  of the SIMM  10  illustrated in FIG. 1). By reducing the size or length L and thus the amount of material necessary to form the module board  62 , the overall cost of manufacturing the SIMM  60  is decreased. However, to connect and properly align such a reduced-size SIMM  60  to a conventional SIMM socket, as known in the art, the SIMM  60  can employ the adapter  40  of the present invention, preferably made of a less expensive material than the material used to form the SIMM board  62 . Thus, the adapter  40  may be comprised of a single-piece molded plastic housing, or formed of other materials known in the art.  
         [37]    37. In yet another preferred embodiment of the present invention, an adapter  80  and SIMM  82  is illustrated in FIGS. 6A and 6B. The adapter  80  is comprised of two connectors or end portions  84  and  86  having a thickness T substantially equal to a thickness of the SIMM board  88  of the SIMM  82 . A C-shaped side wall  90  extends between and depends from the end portions  84  and  86  and substantially covers chips  92  of the SIMM  82 . The end portions  84  and  86  extend a distance beyond the side wall toward the bottom edge  94  of the SIMM board  88  so that the edges  96  and  98  of the end portions  84  and  86 , respectively, are substantially longitudinally flush with the bottom edge  94 . Thus, the side wall  90  is set back a distance from the bottom edge  94  to expose the connectors  100  of the SIMM  82 . The SIMM board  88  is held in relation to the adapter  80  by retaining portions or protrusions  106  and  108  that extend over a portion of the back surface  109  of the SIMM board  88 . Thus, to assemble the SIMM  82  to the adapter  80 , the SIMM  82  can simply be snapped into the adapter  80 . As with other preferred embodiments herein described, the adapter  80  can include holes  102  and  104  and other features of conventional SIMM boards.  
         [38]    38.FIG. 7 is another preferred embodiment of an adapter  110  similar to the adapter  80  shown in FIGS. 6A and 6B, but having a pair of C-shaped side walls  112  and  114  housing a SIMM  116 . As with other embodiments described herein, because the adapter  110  substantially encloses the SIMM  116  and thus protects the components of the SIMM  116 , it is not necessary to provide packaged chips on the SIMM  116  as is typically done with conventional SIMMs. Thus, individual dice  118  can be wire bonded  120  to the SIMM board  122  as shown or flip-chip bonded to the board  122  as is known in the art. The chamber  124  can then be filled with a potting or other material known in the art to form a hermetic or near hermetic seal around the dice  118 .  
         [39]    39.FIGS. 8A and 8B illustrate yet another preferred embodiment of an adapter  130  that is comprised of two end retaining members  132  and  134  similar to other embodiments herein described. The retaining members  132  and  134  of this embodiment, however, are held in relative relation to one another by a slotted or channeled cross-member  136 . The adapter  130  thus fits around at least a portion of the perimeter of a SIMM, such as SIMM  60 , and will properly align the SIMM  60  to a SIMM socket known in the art. If desired, an adhesive or other bonding material can be inserted into the slot  138  to hold the adapter  130  onto the SIMM  60 .  
         [40]    40. In FIG. 9, the adapter  140  may simply be comprised of two connectors or retaining members  142  and  144 . The retaining members  142  and  144  form an adapter  140  similar to the adapter of FIGS. 8A and 8B but without the cross-member  136 . Further illustrated in FIG. 9 is the use of a T-shaped board represented by dashed lines  144 . Thus, the present invention can be adapted to be used in conjunction with various boards and board configurations.  
         [41]    41.FIG. 10 illustrates an adapter  150  similar to the connector  142  of the adapter  140  shown in FIG. 9. The adapter  150  is comprised of a single connector  152  that may be adhesively or otherwise attached to a SIMM board and is configured to resemble the portion of a conventional SIMM board that it is replacing. Preferably, an adhesive or other bonding material is applied to at least a portion of surface  154  and the surface  154  is attached to the back of a SIMM board with abutment portion  156  abutting the side of the SIMM board. If only one side of a SIMM board is being replaced, then only one connector  152  is needed. A similar adapter, however, could be used for the opposite side of the SIMM board.  
         [42]    42.FIG. 11 generally illustrates the module adapter  200  of the present invention installed on another circuit board  202  having a connector  204  therein. The module adapter  200  illustrates the various embodiments of the present invention shown in drawing FIGS. 2 through 10 set forth and described hereinbefore wherein the module adapter comprises either an adapter housing  40 , an adapter  70  comprising a housing having only one side wall  72  extending between the end portions or connectors  74  and  76 , an adapter  80  comprised of two connectors or end portions  84  and  86 , an adapter  110  having a pair of C-shaped side walls  112  and  114 , an adapter  130  comprising retaining members  132  and  134  held in relative relation to one another by a slotted or channeled cross-member  136 , an adapter  140  comprised of two connectors or retaining members  152  and  144 , or an adapter  150  comprised of a single connector  142  attached to a portion of a SIMM board.  
         [43]    43. Referring to drawing FIG. 12, the module and module adapter  200  is shown in conjunction with a computer  300  being connected to a circuit board  302  therein. In this manner, a module and module adapter  200 , the module having a variety of components therein, can be connected to any circuit board  302  of a computer  300  for use therewith.  
         [44]    44. In addition to the embodiments illustrating adapters formed from single-piece molded plastics and the like, it will be appreciated by those skilled in the art that separate components and/or component material could be combined to form such an adapter. Moreover, it will be appreciated by those skilled in the art that variously configured memory modules could be benefitted by the adapters of the present invention. Further, while the invention has been describe with relation to memory devices, the invention may be practiced on many other multi-chip modules where it is desirable to save printed circuit board or other substrate material.  
         [45]    45. It should be noted that the term “SIMM” as used in the specification and appended claims is intended as exemplary and not limiting, the invention having applicability to any multi-chip module. In addition, while preferred embodiments were illustrated as having packaged dice attached to the SIMM board, the invention makes possible the use of bare dice that are wire bonded, flip-chip bonded, or otherwise connected to the substrate.  
         [46]    46. It will also be appreciated by one of ordinary skill in the art that one or more features of any 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. For example, each of the adapters could be L-shaped to secure a portion of the top edge and sides of the module board. 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.