Abstract:
Electronic assemblies and their manufacture are described. One assembly includes a land grid array package including a plurality of land contacts. The assembly also includes a first socket adapted to engage a first group of the plurality of land contacts, and a second socket adapted to engage a second group of the plurality of land contacts. The first socket and the second socket are each coupled to a board. The first socket and the second socket are separate structures on the board. Other embodiments are described and claimed.

Description:
RELATED ART 
       [0001]    Integrated circuits may be formed on semiconductor wafers made of materials such as silicon. The semiconductor wafers are processed to form various electronic devices. The wafers are diced into semiconductor chips (a chip is also known as a die), which may then be attached to a package substrate using a variety of known methods. One type of package substrate is known as a land grid array (LGA) package, which typically includes flat plated gold pads as input/output contacts on the package. The package substrate may then be attached to a printed circuit board (PCB) such as a motherboard through a socket. One advantage of a socket connection is that it is generally possible to remove the package substrate from the socket if desired. The socket typically includes a frame. The socket includes upper contacts that are positioned to electrically couple to the land contacts to the LGA package substrate, and lower contacts that are coupled to the board using, for example, solder bumps. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0002]    Embodiments are described by way of example, with reference to the accompanying drawings, which are not drawn to scale, wherein: 
           [0003]      FIG. 1  illustrates a top view of a dual socket arrangement, in accordance with certain embodiments; 
           [0004]      FIG. 2  illustrates a side cross-sectional view of a dual socket arrangement, in accordance with certain embodiments; 
           [0005]      FIG. 3  illustrates a top view of a dual socket arrangement, including an IC chip on an LGA substrate that is positioned in the sockets, in accordance with certain embodiments; 
           [0006]      FIG. 4  illustrates a side cross-sectional view of a dual socket arrangement, including an IC chip on an LGA substrate that is positioned in the sockets, in accordance with certain embodiments; 
           [0007]      FIG. 5  illustrates a top view of a multiple socket arrangement including four sockets, in accordance with certain embodiments; 
           [0008]      FIG. 6  illustrates a side cross-sectional view of a multiple socket arrangement including four sockets, in accordance with certain embodiments; 
           [0009]      FIG. 7  illustrates a top view of a four socket arrangement, further including an IC chip on an LGA substrate that is positioned in the sockets, in accordance with certain embodiments; 
           [0010]      FIG. 8  illustrates a side cross-sectional view of a four socket arrangement, further including an IC chip on an LGA substrate that is positioned in the sockets, in accordance with certain embodiments; 
           [0011]      FIG. 9  illustrates a flow chart of process operations, in accordance with certain embodiments; 
           [0012]      FIG. 10  illustrates an electronic system arrangement in which embodiments may find application. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    As electronic devices continue to increase in density, reduction of the height of the electronic assembly becomes essential. As more contacts are needed on a package, a socket likewise needs more contacts. The ability to increase the number of contacts in existing LGA socket structures is very limited. As a result, an LGA socket with a larger area for contacts has been contemplated. However, the combination of larger socket area and the need for reduced socket height leads to problems. An increased socket area coupled with reduced height leads to problems with warpage of the socket structure. Socket structures are typically formed from polymer materials. If the LGA socket is substantially warped, then one or more of the following problems may occur, including: (i) non-uniform electrical contact between the package substrate contacts and the contacts in the socket; (ii) stress concentration on parts of the package, which can lead to a shorter lifetime; (iii) difficulties in fitting the package into the socket and applying force to hold the package in the socket without damaging the package. 
         [0014]    Certain embodiments relate to assemblies and methods that permit the use of additional contacts while keeping the socket height minimal.  FIGS. 1-2  illustrate a dual socket embodiment including two LGA sockets  10 ,  20 .  FIG. 1  is a top view and  FIG. 2  is a side cross-sectional view along the dotted line A-A′. As seen in  FIG. 1 , the socket  10  includes sidewalls  12 ,  14 , and  16  extending around three sides of the socket. The fourth side  18  of the socket  10  does not have a sidewall, so that an LGA package can fit within the socket  10  and extend beyond side  18 . The socket  20  similarly includes three sidewalls  22 ,  24 , and  26 . The fourth side  28  has no sidewall, and a package may be positioned to fit in both sockets  10  and  20 , extending over the sides  18  and  28  and within the walls  12 ,  14 ,  16 ,  22 ,  24 , and  26 . As illustrated in the embodiment of  FIGS. 1-2 , a gap  19  exists between the side  18  of socket  10  and the side  24  of socket  20 . The gap  19  may be very narrow so as to permit contacts on the package substrate located close to the gap  19  to be able to be properly positioned onto socket contacts. The sockets  10  and  20  may be formed as separate structures whose frames are not directly attached to each other. It may be possible in certain embodiments that the adjacent sockets could be touching, however, the sockets themselves are independent structures which may be coupled to a board separately. 
         [0015]    As illustrated in  FIG. 2 , a plurality of socket contacts  30  are positioned in each of the sockets  10  and  20 . These contacts  30  are electrically coupled through pathways  32  to contacts  34  on the bottom of the sockets  10  and  20 . The contacts  34  may be coupled to a board such as, for example, a motherboard, using, for example, solder bumps  34 . 
         [0016]      FIGS. 3-4  illustrate a top view and a side cross-sectional view (along the dotted line B-B′) of a dual socket arrangement such as illustrated in  FIGS. 1-2 , including an LGA package substrate having an integrated circuit (IC) chip  6  positioned thereon. The package fits within the walls  12 ,  14 ,  16  of socket  10  and within the walls  22 ,  24 ,  26  of socket  20 . The package also extends over the gap  19  between the sockets  10  and  20 . As illustrated in  FIG. 4 , the LGA substrate includes land contacts  40  that are positioned in electrical contact with the socket contacts  30  in each of the sockets  10  and  20 . A first group G 1  of the land contacts  40  will be positioned within the socket  10 , and a second group G 2  of the land contacts  40  will be positioned within the socket  20 , as indicated by the dotted line brackets in  FIG. 4 . Any suitable LGA contact structure may be used. In addition, any suitable apparatus and method for applying a force to ensure proper contact between the land contacts on the package and the socket contacts may be utilized, if desired. Certain embodiments may utilize a single apparatus to apply a force to hold the LGA package to both sockets at the same time. 
         [0017]    Embodiments also may utilize more than two socket structures into which a single package is positioned.  FIGS. 5 and 6  illustrate a top view and a side cross-section view (along the dotted line C-C′) of an embodiment in which four LGA sockets  101 ,  103 ,  105 , and  107  are utilized to contain an LGA package. The sockets each include two sidewalls forming a corner region, with socket  101  including sidewalls  110  and  112 , socket  103  including sidewalls  114  and  116 , socket  105  including sidewalls  118  and  120 , and socket  107  including sidewalls  122  and  124 .  FIGS. 7 and 8  illustrate a top view and a side cross-sectional view (along the dotted line D-D′) of a socket arrangement such as in  FIGS. 5 and 6 , including a package substrate  108  and IC chip  106  positioned on the four sockets  101 ,  103 ,  105 , and  107 . In this embodiment, with four sockets being used, the sockets may be formed to be very thin, because the individual socket area may be relatively small. 
         [0018]    In addition, when two sockets were used to contain a package, as described above, each socket included three sidewalls, which may be used to assist in positioning the package. When four sockets are used, each socket includes two sidewalls, as illustrated in  FIGS. 5 and 7 . It should be appreciated that the sidewalls, while illustrated as extending along the entire length of a side of the socket, may also be formed to extend along only a part of a side of the socket, or could have a number of spaced apart openings. In other embodiments, the wall may be formed from a number of spaced apart structures such as pins. A purpose for the wall is to assist in the positioning of the substrate in the socket, so the wall may act as an alignment mechanism. As a result, a continuous wall may not be necessary to ensure proper positioning of the substrate in the socket. 
         [0019]    In addition, various embodiments may include any number of sockets may be used, with certain embodiments including either two or four. Depending on the number of sockets used, it is possible that no walls would be need for sockets that are positioned in an interior region. In addition, depending on the layout of the package contacts, the sockets could vary in size and shape from one another. 
         [0020]      FIG. 9  illustrates a flowchart of operations, in accordance with certain embodiments. Box  300  is providing an LGA package having first and second groups of separate land contacts. Box  302  is bringing the first group of land contacts into electrical contact with socket contacts in the first socket. Box  304  is bringing the second group of land contacts into electrical contact with socket contacts in the second socket. In certain embodiments the first group and the second group are brought into contact with the socket contacts at the same time or approximately the same time. 
         [0021]    Certain embodiments may provide one or more of the following advantages when compared with conventional single socket mounting of packages. First, in accordance with certain embodiments, a more thin and less warped socket may be manufactured because the socket may have a smaller area. Second, by using multiple thin sockets that are less likely to have warpage problems, more area may be available for obtaining a higher number of contacts. Third, it may be simpler to produce a greater number of smaller sockets, instead of forming a single large socket. 
         [0022]    Assemblies including components formed as described in embodiments above may find application in a variety of electronic components.  FIG. 10  schematically illustrates one example of an electronic system environment in which aspects of described embodiments may be embodied. Other embodiments need not include all of the features specified in  FIG. 10 , and may include alternative features not specified in  FIG. 10 . 
         [0023]    The system  401  of  FIG. 10  may include at least one central processing unit (CPU)  403 . The CPU  403 , also referred to as a microprocessor, may be a die which is attached to an integrated circuit package substrate  405 , which is then coupled to a printed circuit board  407  (for example, a motherboard) through sockets  419  and  421 . The sockets  419  and  421  to which the package substrate  405  containing the CPU  403  is coupled are an example of an assembly that may be formed in accordance with embodiments such as described above, including multiple socket structures to contain a package. A variety of other system components, including, but not limited to memory and other components discussed below, may also include structures formed in accordance with embodiments such as described above. 
         [0024]    The system  401  may further include memory  409  and one or more controllers  411   a ,  411   b  . . .  411   n,  which are also disposed on the motherboard  407 . The motherboard  407  may be a single layer or multi-layered board which has a plurality of conductive lines that provide communication between the circuits in the package  405  and other components mounted to the board  407 . Alternatively, one or more of the CPU  403 , memory  409  and controllers  411   a ,  411   b  . . .  411   n  may be disposed on other cards such as daughter cards or expansion cards. The CPU  403 , memory  409  and controllers  411   a,    411   b  . . .  411   n  may each be seated in sockets or may be connected directly to a printed circuit board or all integrated in the same package. A display  415  may also be included. 
         [0025]    Any suitable operating system and various applications execute on the CPU  403  and reside in the memory  409 . The content residing in memory  409  may be cached in accordance with known caching techniques. Programs and data in memory  409  may be swapped into storage  413  as part of memory management operations. The system  401  may comprise any suitable computing device, including, but not limited to, a mainframe, server, personal computer, workstation, laptop, handheld computer, netbook, tablet, book reader, handheld gaming device, handheld entertainment device (for example, MP3 (moving picture experts group layer-3 audio) player), PDA (personal digital assistant) telephony device (wireless or wired), network appliance, virtualization device, storage controller, network controller, router, etc. 
         [0026]    The controllers  411   a,    411   b  . . .  411   n  may include one or more of a system controller, peripheral controller, memory controller, hub controller, I/O (input/output) bus controller, video controller, network controller, storage controller, communications controller, etc. For example, a storage controller can control the reading of data from and the writing of data to the storage  413  in accordance with a storage protocol layer. The storage protocol of the layer may be any of a number of known storage protocols. Data being written to or read from the storage  413  may be cached in accordance with known caching techniques. A network controller can include one or more protocol layers to send and receive network packets to and from remote devices over a network  417 . The network  417  may comprise a Local Area Network (LAN), the Internet, a Wide Area Network (WAN), Storage Area Network (SAN), etc. Embodiments may be configured to transmit and receive data over a wireless network or connection. In certain embodiments, the network controller and various protocol layers may employ the Ethernet protocol over unshielded twisted pair cable, token ring protocol, Fibre Channel protocol, etc., or any other suitable network communication protocol. 
         [0027]    Terms such as “first”, “second”, and the like as used herein to not necessarily denote any particular order, quantity, or importance, but are used to distinguish one element from another. Terms such as “top”, bottom”, “upper”, and “lower” and the like as used herein refer to the orientation of features as illustrated in the attached figures. 
         [0028]    While certain exemplary embodiments have been described above and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative and not restrictive, and that embodiments are not restricted to the specific constructions and arrangements shown and described since modifications may occur to those having ordinary skill in the art.