Patent Document

[0001]    This application is a Continuation of U.S. application Ser. No. 09/261,608, filed Feb. 26, 1999 which is incorporated herein by reference. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    This invention relates to electronic systems, and more particularly, it relates to circuit packaging in electronic systems.  
         BACKGROUND OF THE INVENTION  
         [0003]    A personal computer is one example of an electronic system that is constantly being upgraded. Upgrading a personal computer often requires following a complex procedure and using specialized tools. For example, in some personal computers, the process for adding memory modules requires the use of a soldering iron and performing a sequence of operations to secure each memory module to the memory board. Processes that require following a complex procedure and using a soldering iron tend to intimidate many computer users. So, adding memory modules to a personal computer during the upgrade of a personal computer is often performed by a skilled technician. Unfortunately, using a skilled technician to upgrade a personal computer makes the process very expensive.  
           [0004]    Memory upgrade kits exist for some types of personal computers. These kits include memory modules mounted on a printed circuit board. One edge of the printed circuit board has conducting pins for insertion into a matching connector mounted on the memory board. At first glance, for personal computers that support these memory upgrade kits, it appears that adding memory modules to a personal computer using an upgrade kit is a process that is easily performed. Unfortunately, many personal computer users are unable to successfully add memory to their computers using these kits. Users often use an excessive amount of force while attempting to insert the printed circuit board into the matching connector or fail to accurately align memory module pins with the matching connector on the memory board. Using excessive force or failing to accurately align memory module pins with the matching connector often results in broken printed circuit boards and broken memory module pins.  
           [0005]    For these and other reasons there is a need for the present invention.  
         SUMMARY OF THE INVENTION  
         [0006]    The above mentioned problems with packaging circuits and other problems are addressed by the present invention and will be understood by reading and studying the following specification. An apparatus and method for packaging circuits is described.  
           [0007]    In one embodiment, an apparatus includes a module and a socket. The module has an edge, a coupling site, and an alignment feature located along the edge. The socket has an edge, an alignment feature, a guide, and a coupling site. The guide is located along the socket edge and is capable of guiding the module alignment feature into contact with the socket alignment feature as the module is inserted into the socket. During this insertion process, the module edge is in contact with the guide, and the module coupling site is capable of contacting the socket coupling site when the module alignment feature interlocks with the socket alignment feature.  
           [0008]    In another embodiment, an apparatus includes a substrate, a chip, and a socket. The substrate has an alignment feature, and the chip is mounted on the substrate. The socket has an alignment feature, a guide, and a retaining feature. The socket is capable of receiving the substrate and aligning the substrate to the socket using the guide, capable of restricting the lateral motion of the substrate using the retaining feature, and capable of interlocking with the substrate by interlocking the socket alignment feature with the substrate alignment feature while using only a small insertion force.  
           [0009]    In another embodiment, a method of adding integrated circuits to a system includes aligning and sliding operations. In the aligning operation, an edge of a module having an alignment feature is aligned with a guide feature of a socket having an alignment feature. In the sliding operation, the edge of the module slides along the guide feature until the module alignment feature interlocks with the socket alignment feature.  
           [0010]    In another embodiment, a method of adding integrated circuits to a system includes grasping, aligning, sliding and releasing operations. In the grasping operation, a module is grasped. In the aligning operation, an edge of the module is aligned with a guide feature of a socket. In the sliding operation, the edge of the module slides along the guide feature until a module alignment feature interlocks with a socket alignment feature. In the releasing operation, the module is released. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    [0011]FIG. 1 is an exploded perspective view of some embodiments of a chip carrier system of the present invention.  
         [0012]    [0012]FIG. 2 is a side view of some embodiments of an assembled chip carrier system of the present invention.  
         [0013]    [0013]FIG. 3 is a block diagram of a system in which some embodiments of present invention can be practiced. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0014]    In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific preferred embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that logical, mechanical and electrical changes may be made without departing from the spirit and scope of the present inventions. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims.  
         [0015]    [0015]FIG. 1 shows an exploded perspective view of some embodiments of chip carrier system  100  which comprises two basic components, module  103  and socket  106 . FIG. 1 also shows printed circuit board  109  on which chip carrier system  100  can be mounted. Although chip carrier system  100  is capable of packaging and interconnecting a variety of integrated circuits, such as analog circuits, mixed signal application specific circuits, and digital circuits, it is particularly suited through its modular embodiment to applications involving the packaging of memory circuits.  
         [0016]    Module  103 , in one embodiment, comprises substrate  112 , edges  114 ,  115 ,  116 , and  117 , chip  118 , and alignment feature  124 .  
         [0017]    Chip  118  is mounted on substrate  112 . Substrate  112 , in one embodiment, is made of a conducting material, such as copper, aluminum or gold, or an alloy of such a conducting material. One function of substrate  112  is to transfer heat away from chip  118 . Fabricating substrate  112  from a material that is not a good conductor can lead to the catastrophic failure of chip  118 , if the material selected for substrate  112  fails to efficiently transfer heat away from chip  118 .  
         [0018]    Chip  118 , in one embodiment, is mounted face down on substrate  112 , and is secured to substrate  112  using a heat conducting adhesive. The heat conducting adhesive provides a path for the heat generated by chip  118  to flow into substrate  112 . The rate at which heat is removed from chip  118  can be increased by directing air flow across the surface of substrate  112 .  
         [0019]    Chip  118  includes coupling site  127 , which in one embodiment comprises contact pads  130 . Contact pads  130  provide a direct connection to the circuits and devices on chip  118 . In an alternate embodiment, coupling site  127  comprises pins or other similar connectors, and these pins or other similar connectors are in turn coupled to contact pads  130 .  
         [0020]    Edges  114 ,  115 ,  116  and  117  are preferably planar surfaces. A planar surface makes substrate  112  simple to manufacture, easy to grasp, and permits quick insertion of module  103  into socket  106 .  
         [0021]    Alignment feature  124  is used to register module  103  with socket  106 . When module  103  is registered with socket  106  module coupling site  127  is aligned with socket coupling site  133 . Alignment of module coupling site  127  with socket coupling site  133  permits communication between chip  118  and the circuits, chips or devices located on circuit board  109  or coupled to circuit board  109 . Failure to align module coupling site  127  to socket coupling site  133  may result in the isolation of chip  118  from the circuits, chips or devices located on circuit board  109 .  
         [0022]    Alignment feature  124 , in one embodiment, is a curved indentation or notch capable of interlocking with a half-cylinder, which is the corresponding alignment feature located on socket  106 . This configuration of alignment features permits the insertion of module  103  into socket  106  using a low or zero insertion force, yet restricts the motion of module  103  with respect to socket  106  in the non-lateral direction. Restricting the motion of module  103  in the non-lateral direction ensures the continued alignment of coupling site  127  with socket coupling site  133 .  
         [0023]    Socket  106 , in one embodiment, comprises edge  134 , surface  136 , alignment feature  139 , guide  142 , socket coupling site  133 , and retaining feature  147 . Socket  106  is preferably an injection molded component made of nylon or any other suitable plastic material. Alternatively, socket  106  can be machined from a single piece of plastic or other appropriate material.  
         [0024]    Guide  142  is located along edge  134  of socket  106 . Guide  142 , in one embodiment, has the shape of an el, as shown in FIG. 1, and can be fabricated as an integrated component of socket  106 . El shaped guide  142  provides for quick, easy and accurate insertion of module  103  into guide  142 . Once inserted into guide  142 , module  103  slides along the inside edge of guide  142  until it is seated in socket  106 . An advantage of this embodiment is that an untrained person can successfully insert module  103  into socket  106  without damaging components of either module  103  or socket  106 .  
         [0025]    Alignment feature  139  interlocks with module alignment feature  124 . In one embodiment, alignment feature  139  has a smooth shape, such as the shape of a half cylinder as shown in FIG. 1. Using a half cylinder shape, which lacks sharp corners, for alignment feature  139  makes the final alignment and interlocking of module  103  with socket  106  an easy operation to perform. Module  103  slides easily into place once module alignment feature  124  engages socket alignment feature  139 , since there are no sharp corners to interfere with the interlocking of module alignment feature  124  with socket alignment feature  139 . The present invention is not limited to alignment feature  139  having a half cylinder shape. Other shapes will also permit easy insertion of module  103  into socket  106 .  
         [0026]    Socket alignment feature  139  is approximately centered along the longest dimension of surface  136  of socket  106 , and is preferably fabricated as an integrated component of socket  106 . Centering socket alignment feature  139  makes the operation of inserting module  103  into socket  106  and interlocking module  103  with module  106  easier than if the socket alignment feature  139  is located off center. Socket alignment feature  139  also serves to restrict the non-lateral motion of module  103 , which keeps module coupling site  127  aligned with socket coupling site  133 .  
         [0027]    Retaining feature  147  restricts the lateral motion of module  103 . In one embodiment, retaining feature  147  is a lip located along an edge of surface  136 . Restricting the lateral motion of module  103  forces module coupling site  127  to stay coupled to socket coupling site  133 . The location of retaining feature  147  and the amount to which the lateral motion of module  103  is restricted is determined by the characteristics of module coupling site  127  and socket coupling site  133 . If module coupling site  127  comprises pads on an integrated circuit chip, and coupling site  133  comprises contacts for those pads, then the proper amount of restriction is achieved by having retaining feature  147  located such that module  103  couples to socket  106  with an amount of force equivalent to a press fit. As with guide  142 , retaining feature  139  is preferably fabricated as an integrated component of socket  106 .  
         [0028]    Printed circuit board  109  provides a platform for mounting socket  106 , and a platform on which other circuit modules, such as circuit module  150 , can be mounted and coupled to socket  106 . The present invention is not limited to a particular type of printed circuit board technology. Socket  106  can be mounted on a single or multilayer board, and can be secured to the board using an adhesive. Alternatively, socket  106  can be secured to the board using an epoxy.  
         [0029]    [0029]FIG. 2 is a side view of some embodiments of an assembled chip carrier system  100  of the present invention. Module  103  is assembled with socket  106  using a press fit, and the assembled chip carrier system  100  is mounted on printed circuit board  109 . In the embodiments shown, module  103  is interlocked with socket  106  at module alignment feature  124  and socket alignment feature  139 .  
         [0030]    The seating and retention of module  103  in socket  106  is best understood by describing the functioning of socket alignment feature  139 , module alignment feature  124 , retaining feature  147 , and guide  142  in the assembled chip carrier system  100 . Socket alignment feature  139  and module alignment feature  124  restrict the non-lateral motion of module  103  once socket alignment feature  139  is interlocked with module alignment feature  124 . Retaining feature  147  abuts module  103 , and ensures that socket coupling site  133  is in contact with module coupling site  127  by restricting the lateral motion of module  103  after module  103  is seated in socket  106 . Guide  142  assists retaining feature  147  in keeping module coupling site  127  in contact with socket coupling site  133  by restricting the lateral motion of the top of module  103 .  
         [0031]    Signals can flow from chip  118  mounted on substrate  103  to circuit module  150  mounted on printed circuit board  109 . The flow of signals between chip  118  and module  150  is best understood by following the conducting pattern from socket coupling site  133  to circuit module  150 . Module coupling site  127  is in contact with socket coupling site  133 . Conductor  152  couples socket coupling site  133  to socket board contact site  155 . A second conductor  158  couples circuit board contact site  155  to circuit module  150 .  
         [0032]    Referring to FIG. 3, a block diagram of a system level embodiment of the present invention is shown. System  300  comprises processor  305  and memory device  310 , which includes memory cells of one or more of the types described above in conjunction with FIGS.  1 - 2 . Memory device  310  comprises memory array  315 , address circuitry  320 , and read circuitry  330 , and is coupled to processor  305  by address bus  335 , data bus  340 , and control bus  345 . Processor  305 , through address bus  335 , data bus  340 , and control bus  345  communicates with memory device  310 . In a read operation initiated by processor  305 , address information, data information, and control information are provided to memory device  310  through busses  335 ,  340 , and  345 . This information is decoded by addressing circuitry  320 , including a row decoder and a column decoder, and read circuitry  330 . Successful completion of the read operation results in information from memory array  315  being communicated to processor  305  over data bus  340 .  
         [0033]    Memory circuits or cells, when mounted in the chip carrier system of the present invention, become addressable as elements of memory array  315  in the system shown in FIG. 3.  
       Conclusion  
       [0034]    Embodiments of an apparatus and method for packaging circuits has been described. A module and socket capable of being easily aligned, assembled and interlocked has been described. In an alternative embodiment, a substrate, a chip, and a socket also capable of being easily aligned, assembled and interlocked has been described. In addition, a method of aligning a module with the guide feature of a socket, sliding the module along the edge of the guide, and interlocking the module with the socket has been described.  
         [0035]    Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement which is calculated to achieve the same purpose may be substituted for the specific embodiment shown. This application is intended to cover any adaptations or variations of the present invention. Therefore, it is manifestly intended that this invention be limited only by the claims and the equivalents thereof.

Technology Category: h