Abstract:
A pivotally mounted load plate may be provided with downwardly extending protrusions that engage corresponding slots in an integral heat spreader. As a result, when the load plate is rotated onto the integral heat spreader, alignment may be maintained.

Description:
BACKGROUND  
       [0001]     This invention relates generally to mounting integrated circuits on circuit boards such as motherboards.  
         [0002]     Conventionally, packaged integrated circuits, such as a processor, may be provided through a socket for securement to a printed circuit board such as a motherboard. There are a variety of different ways of making connections between the integrated circuit and the board. One such way is a land grid array, in which surface mount techniques are utilized to connect the socket to the printed circuit board. A load plate may be utilized to force the integrated circuit into tight electrical connection to the socket.  
         [0003]     One problem that arises is that the force applied through the load plate may result in relative horizontal movement in the plane of the socket between the load plate and an integral heat spreader provided with the integrated circuit package. This may cause the integrated circuit package to be seated improperly within the socket body. Improper seating may result in open circuits.  
         [0004]     Thus, there is a need for better ways to secure packaged integrated circuits to sockets.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]      FIG. 1  is a perspective view of one embodiment of the present invention;  
         [0006]      FIG. 2  is an exploded view of the embodiment shown in  FIG. 1 ;  
         [0007]      FIG. 3  is a top plan view of one embodiment of the present invention with the load plate removed; and  
         [0008]      FIG. 4  is a cross-sectional view taken generally along the line  4 - 4  in  FIG. 1 . 
     
    
     DETAILED DESCRIPTION  
       [0009]     Referring to  FIGS. 1 and 2 , a land grid array socket assembly  10  may include a packaged integrated circuit  24  held within a socket  34  by a load plate  12 . The load plate  12  may hingedly connect to a socket body stiffener  28 . The stiffener  28  is secured to the socket  34 . To this end, U-shaped clips  22  may be provided on the load plate  12  that engage openings  30  in the socket body stiffener  28 . Thus, the load plate  12  may hinge about the openings  30  in the stiffener  28 .  
         [0010]     The load plate  12  may be cammed downwardly to get good electrical connection between contacts on the integrated circuit  24  and the socket  34  by an actuator  16 . The actuator  16 , in one embodiment, may be part of an integral L-shaped bar  14 , having a curved end that may be latched under a catch  32 , in one embodiment, to lock the load plate  12  into engagement with the integrated circuit  24 . In particular, the actuator  16  may be rotated counterclockwise around and down as the load lever  14  is rotated within its tubular retainer  20 .  
         [0011]     Alignment between the load plate  12  and an integral heat spreader  48  may be ensured by downwardly projecting protrusions  42  which engage mating slots  46  in the upper surface of the integral heat spreader  44 . When the load plate  12  is a metal stamping, the protrusions  42  may be formed during the stamping process.  
         [0012]     Thus, referring to  FIG. 2 , the socket body stiffener  28  may receive the socket body  34 . The stiffener  28  also includes the retainer  20  that secures the load lever  14  to the assembly  10 . Thus, the actuator  16  may rotate counterclockwise through about  90  degrees from the closed position, shown in  FIG. 2 , to an open position.  
         [0013]     The packaged integrated circuit  24  may be seated within the integral heat spreader  44 . With the load plate  12  clips  22  engaged in the openings  30  in the stiffener  28 , the load plate  12  may be rotated counter-clockwise over the integral heat spreader  44 . The load lever  14  may be rotated upwardly or counterclockwise from the position shown in  FIG. 2 . The free end  25  of the load plate  12  may be positioned to be engaged and pressed downwardly by the rotating actuator  16  as the load lever  14  rotates to the position shown in  FIGS. 1 and 2 , latched under the catch  32 .  
         [0014]     As all of this is happening, the protrusions  42  and mating slots  46  maintain close alignment between the load plate  12  and the integral heat spreader  44 , preventing horizontal displacement between those parts and the packaged integrated circuit  24 .  
         [0015]     Without the alignment features, such as the slots  46  and protrusions  42 , the play between the clips  22  and openings  30  permit relative movement between the load plate  12  and the stiffener  28  towards or away from the retainer  20 . Depending on the direction of such horizontal displacement, non-uniform pressure is applied to the socket  34  along the line between the openings  30  and retainer  20 . This non-uniform pressure may result in poor electrical connections. The provision of the alignment features keeps the load plate  12  centered over the socket  34  enabling the load plate  12  to apply more uniform pressure to the contacts between the integrated circuit  24  and the socket  34 .  
         [0016]     Thus, referring to  FIG. 3 , the slots  46  in the integral heat spreader  44  are arranged to control horizontal sliding movement during load plate  12  actuation. The slots  46  and protrusions  42  prevent relative movement between the integral heat spreader  44  or integrated circuit package  24  and the load plate  12 .  
         [0017]     As better shown in  FIG. 4 , the load plate  12  downward protrusions  46  can engage the upwardly facing slots  46  in the integral heat spreader  44 . The socket body stiffener  28  then holds the whole assembly together.  
         [0018]     In some embodiments, not only is horizontal movement of the load plate prevented during the socket actuation, reducing the risk of opens caused by improper packaged seating, but the slots  46  in the integral heat spreader  44  may also serve as additional alignment features to ensure that the package  24  is inserted in the right orientation.  
         [0019]     While an embodiment is illustrated in which downward protrusions are formed on the load plate and mating slots are formed on the integral heat spreader, other arrangements for alignment features may be utilized as well. For example, the alignment feature on the load plate may be an indentation that receives a protrusion on the integral heat spreader. Other arrangements and orientations of the alignment features may also be possible. Similarly, the number of alignment features may be varied.  
         [0020]     While the present invention has been described with respect to a limited number of embodiments, those skilled in the art will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of this present invention.