Single-piece molded module housing

CROSS-REFERENCE TO RELATED APPLICATIONS

0001[0001] This application is a continuation of application Ser. No. 09/737,288, filed Dec. 13, 2000, pending, which is a continuation of application Ser. No. 09/205,872, filed Dec. 4, 1998, now U.S. Pat. No. 6,233,154,B1, issued May 15, 2001, 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

0002[0002] 1. Field of the Invention

0003[0003] 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.

0004[0004] 2. State of the Art

0005[0005] 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.

0006[0006] 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.

0007[0007] 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.

0008[0008] 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.

0009[0009] 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 a strain-to-fracture ratio of about 0.04, thereby providing enough resiliency for good metal or glass bond interfaces.

0010[0010] 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.

0011[0011] 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.

0012[0012] 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.

0013[0013] 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.

0014[0014] 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

0015[0015] 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.

0016[0016] 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.

0017[0017] 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.

0018[0018] 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.

0019[0019] 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

0020[0020]FIG. 1 is a perspective view of a prior art SIMM;

0021[0021]FIG. 2 is a perspective view of a first preferred embodiment of a SIMM adapter according to the present invention;

0022[0022]FIGS. 3A and 3B are schematic views of a reduced-size SIMM sized to fit within the SIMM adapter of FIG. 2;

0023[0023]FIG. 4 is a perspective view of the SIMM of FIGS. 3A and 3B inserted into the SIMM adapter of FIG. 2.

0024[0024]FIG. 5 is a perspective view of a second embodiment of a SIMM adapter according to the present invention;

0025[0025]FIGS. 6A and 6B are schematic drawings of a third embodiment of a SIMM adapter according to the present invention;

0026[0026]FIG. 7 is a schematic drawing of a fourth embodiment of a SIMM adapter according to the present invention;

0027[0027]FIGS. 8A, 8B, and <b>8</b>C are schematic drawings of a fifth embodiment of a SIMM adapter according to the present invention, wherein FIG. 8C illustrates an alternative embodiment to the fifth embodiment illustrated in FIGS. 8A and 8B;

0028[0028]FIG. 9 is a perspective view of a sixth embodiment of a SIMM adapter according to the present invention;

0029[0029]FIG. 10 is a perspective view of a seventh embodiment of a SIMM adapter according to the present invention;

0030[0030]FIG. 11 is a side view of a general illustration of the SIMM adapter of the present invention connected to another circuit board; and

0031[0031]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

0032[0032] Referring to FIG. 1, a prior art, single in-line memory module (SIMM) <b>10</b> is illustrated and comprised of a module board <b>12</b>, typically a printed circuit board, with a plurality of semiconductor devices <b>14</b> attached thereto. In a SIMM, each of the semiconductor devices <b>14</b> is usually the same type and size and arranged in a row longitudinally across the printed circuit board <b>12</b>. The printed circuit board <b>12</b> is generally rectangular in shape and has a row of contacts <b>13</b> along a bottom edge <b>15</b> of the board <b>12</b>. The printed circuit board <b>12</b> also includes holes <b>16</b> and <b>18</b> proximate each end <b>20</b> and <b>22</b> of the board <b>12</b>, respectively, and a J-shaped notch <b>24</b> on the corner <b>26</b> of the board <b>12</b> to assist alignment of the contacts <b>13</b> with a SIMM socket or connector as is known in the art. As illustrated by dashed lines <b>28</b> and <b>30</b>, the printed circuit board <b>12</b> material, typically FR-4, between the dashed line <b>28</b> and the end <b>20</b> and between the dashed line <b>30</b> and the end <b>22</b> is merely used to attach and align the SIMM <b>10</b> to a SIMM socket, and could be eliminated from the SIMM <b>10</b> without any loss of functionality. In order to properly attach and align the SIMM <b>10</b> to an industry standard SIMM socket, however, without the use of the adapter according to the present invention, the portions <b>17</b> and <b>19</b> of the board <b>12</b> extending beyond the lines <b>28</b> and <b>30</b> are needed.

0033[0033] Referring now to FIGS. 2, 3A, <b>3</b>B, and <b>4</b>, a first preferred embodiment of an adapter or housing <b>40</b> according to the present invention is illustrated. The housing <b>40</b>, generally a rectangular box shape, is comprised of a first side wall <b>42</b> and a second side wall <b>44</b> depending from and extending between a first connector or retaining member <b>46</b> and a second connector or retaining member <b>48</b>. The side walls <b>42</b> and <b>44</b> and the connectors <b>46</b> and <b>48</b> of the housing <b>40</b> form a chamber <b>41</b> into which a SIMM <b>60</b> or the like can be inserted (see FIGS. 3A and 3B), the side walls <b>42</b> and <b>44</b> being separated a distance sufficient to allow clearance for the SIMM <b>60</b> and any chips <b>66</b> or components <b>68</b> thereon. The side walls <b>42</b> and <b>44</b> may also include holes <b>43</b> and <b>45</b> and other features of a conventional SIMM <b>10</b> so that the housing <b>40</b> and the SIMM <b>60</b> therein properly fit within a SIMM socket as known in the art.

0034[0034] To keep a SIMM <b>60</b> or the like securely positioned within the chamber <b>41</b>, the connectors <b>46</b> and <b>48</b> define slots <b>50</b> and <b>52</b>, respectively, that longitudinally extend along a length of each connector <b>46</b> and <b>48</b>. The slots <b>50</b> and <b>52</b> are sized and spaced from one another so that a SIMM board <b>62</b> fits snugly therein. In addition, the connectors <b>46</b> and <b>48</b> include extended portions or tabs <b>54</b> and <b>56</b>, respectively, that are aligned with and generally the same width as the slots <b>50</b> and <b>52</b>, and thus generally the same width W as the SIMM board <b>62</b>. As shown in FIG. 4, when the SIMM <b>60</b> is properly inserted into the housing <b>40</b>, the tabs <b>54</b> and <b>56</b> extend substantially the same distance as the bottom edge <b>64</b> of the SIMM <b>60</b> so that the end surfaces <b>55</b> and <b>57</b> of the tabs <b>54</b> and <b>56</b>, respectively, are substantially flush with the bottom edge <b>64</b>. If desired, once the SIMM <b>60</b> is properly inserted, any spaces between the SIMM <b>60</b> and the inside of the housing <b>40</b> could be potted or otherwise filled with a potting or other compound known in the art to ensure that the SIMM <b>60</b> remains fixed to the housing <b>40</b>.

0035[0035] Referring now to FIG. 5, another preferred embodiment of a holder or adapter <b>70</b> according to the present invention is illustrated. This embodiment is similar to the housing <b>40</b> of FIG. 2 but has only one side wall <b>72</b> extending between the end portions or connectors <b>74</b> and <b>76</b>. Thus, a SIMM such as SIMM <b>10</b>, with portions <b>17</b> and <b>19</b> removed, can be inserted therein with the semiconductor devices <b>14</b> facing the inside of the side wall <b>72</b>, or inserted with the semiconductor devices <b>14</b> being exposed. Preferably, the semiconductor devices <b>14</b> face the inside of the side wall <b>72</b> so that any aesthetic anomalies on the SIMM <b>10</b> are covered by the side wall <b>72</b>. In addition, a J-shaped recess <b>78</b> may be incorporated in the connector <b>74</b> to substantially duplicate the configuration of the SIMM <b>10</b> for proper seating of the adapter <b>70</b> and SIMM <b>10</b> within a conventional SIMM socket. Moreover, as with the housing <b>40</b>, any spaces between the SIMM <b>10</b> and the inside of the side wall <b>72</b> can be potted or otherwise filled with other materials known in the art.

0036[0036] To illustrate that the present invention has applicability to various memory modules, the SIMM <b>60</b> of FIGS. 3A and 3B is of a different configuration than the SIMM <b>10</b> of FIG. 1, SIMM <b>10</b> being an older type conventional SIMM and the SIMM <b>60</b> being a more current SIMM version. Unlike the SIMM <b>10</b> of FIG. 1, however, SIMM <b>60</b>, while otherwise having a conventional configuration, does not have the same length L as the conventional SIMM <b>10</b> (i.e., not including the portions <b>17</b> and <b>19</b> of the SIMM <b>10</b> illustrated in FIG. 1). By reducing the size or length L and thus the amount of material necessary to form the SIMM board <b>62</b>, the overall cost of manufacturing the SIMM <b>60</b> is decreased. However, to connect and properly align such a reduced-size SIMM <b>60</b> to a conventional SIMM socket, as known in the art, the SIMM <b>60</b> can employ the adapter <b>40</b> of the present invention, preferably made of a less expensive material than the material used to form the SIMM board <b>62</b>. Thus, the adapter <b>40</b> may be comprised of a single-piece molded plastic housing, or formed of other materials known in the art.

0037[0037] In yet another preferred embodiment of the present invention, an adapter <b>80</b> and SIMM <b>82</b> is illustrated in FIGS. 6A and 6B. The adapter <b>80</b> is comprised of two connectors or end portions <b>84</b> and <b>86</b> having a thickness T substantially equal to a thickness of the SIMM board <b>88</b> of the SIMM <b>82</b>. A C-shaped side wall <b>90</b> extends between and depends from the end portions <b>84</b> and <b>86</b> and substantially covers chips <b>92</b> of the SIMM <b>82</b>. The end portions <b>84</b> and <b>86</b> extend a distance beyond the side wall go toward the bottom edge <b>94</b> of the SIMM board <b>88</b> so that the edges <b>96</b> and <b>98</b> of the end portions <b>84</b> and <b>86</b>, respectively, are substantially longitudinally flush with the bottom edge <b>94</b>. Thus, the side wall <b>90</b> is set back a distance from the bottom edge <b>94</b> to expose the connectors <b>100</b> of the SIMM <b>82</b>. The SIMM board <b>88</b> is held in relation to the adapter <b>80</b> by retaining portions or protrusions <b>106</b> and <b>108</b> that extend over a portion of the back surface <b>109</b> of the SIMM board <b>88</b>. Thus, to assemble the SIMM <b>82</b> to the adapter <b>80</b>, the SIMM <b>82</b> can simply be snapped into the adapter <b>80</b>. As with other preferred embodiments herein described, the adapter <b>80</b> can include holes <b>102</b> and <b>104</b> and other features of conventional SIMM boards.

0038[0038]FIG. 7 shows another preferred embodiment of an adapter <b>110</b> similar to the adapter <b>80</b> shown in FIGS. 6A and 6B, but having a pair of C-shaped side walls <b>112</b> and <b>114</b> housing a SIMM <b>116</b>. As with other embodiments described herein, because the adapter <b>110</b> substantially encloses the SIMM <b>116</b> and thus protects the components of the SIMM <b>116</b>, it is not necessary to provide packaged chips on the SIMM <b>116</b> as is typically done with conventional SIMMs. Thus, individual dice <b>118</b> can be wire bonded <b>120</b> to the SIMM board <b>122</b> as shown or flip-chip bonded to the board <b>122</b> as is known in the art. The chamber <b>124</b> 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 <b>118</b>.

0039[0039]FIGS. 8A, 8B, and <b>8</b>C illustrate yet another preferred embodiment of an adapter <b>130</b> that is comprised of two end retaining members <b>132</b> and <b>134</b> similar to other embodiments herein described. The retaining members <b>132</b> and <b>134</b> of this embodiment, however, are held in relative relation to one another by a slotted or channeled cross-member <b>136</b>. FIG. 8C illustrates an alternative embodiment using multiple cross-members <b>136</b><i>a </i>and <b>136</b><i>b</i>. The second cross-member <b>136</b><i>b </i>provides further structural support and can be channeled to help align and hold the module board. The adapter <b>130</b> thus fits around at least a portion of the perimeter of a SIMM, such as SIMM <b>60</b>, and will properly align the SIMM <b>60</b> to a SIMM socket known in the art. If desired, an adhesive or other bonding material can be inserted into the slot <b>138</b> to hold the adapter <b>130</b> onto the SIMM <b>60</b>.

0040[0040] In FIG. 9, the adapter <b>140</b> may simply be comprised of two connectors or retaining members <b>142</b> and <b>144</b>. The retaining members <b>142</b> and <b>144</b> form an adapter <b>140</b> similar to the adapter of FIGS. 8A and 8B but without the cross-member <b>136</b>. Further illustrated in FIG. 9 is the use of a T-shaped board represented by dashed lines <b>144</b>′. Thus, the present invention can be adapted to be used in conjunction with various boards and board configurations.

0041[0041]FIG. 10 illustrates an adapter <b>150</b> similar to the connector <b>142</b> of the adapter <b>140</b> shown in FIG. 9. The adapter <b>150</b> is comprised of a single connector <b>152</b> 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 <b>154</b> and the surface <b>154</b> is attached to the back of a SIMM board with abutment portion <b>156</b> abutting the side of the SIMM board. If only one side of a SIMM board is being replaced, then only one connector <b>152</b> is needed. A similar adapter, however, could be used for the opposite side of the SIMM board.

0042[0042]FIG. 11 generally illustrates the module adapter <b>200</b> of the present invention installed on another circuit board <b>202</b> having a connector <b>204</b> therein. The module adapter <b>200</b> 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 <b>40</b>, an adapter <b>70</b> comprising a housing having only one side wall <b>72</b> extending between the end portions or connectors <b>74</b> and <b>76</b>, an adapter <b>80</b> comprised of two connectors or end portions <b>84</b> and <b>86</b>, an adapter <b>110</b> having a pair of C-shaped side walls <b>112</b> and <b>114</b>, an adapter <b>130</b> comprising retaining members <b>132</b> and <b>134</b> held in relative relation to one another by a slotted or channeled cross-member <b>136</b>, an adapter <b>140</b> comprised of two connectors or retaining members <b>142</b> and <b>144</b>, or an adapter <b>150</b> comprised of a single connector <b>152</b> attached to a portion of a SIMM board.

0043[0043] Referring to drawing FIG. 12, the module and module adapter <b>200</b> is shown in conjunction with a computer <b>300</b> being connected to a circuit board <b>302</b> therein. In this manner, a module and module adapter <b>200</b>, the module having a variety of components therein, can be connected to any circuit board <b>302</b> of a computer <b>300</b> for use therewith.

0044[0044] 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 benefited by the adapters of the present invention. Further, while the invention has been described 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.

0045[0045] 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.

0046[0046] 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.