Abstract:
An electrical connector assembly ( 100 ) made in accordance with a preferable embodiment of the present invention comprises an electrical socket ( 20 ) with a plurality of contacts received therein, an IC module ( 30 ) mounted onto the electrical socket ( 20 ) so as to make electrical connection therebetween, a heat sink assembly ( 40 ) pressing on the IC module ( 30 ) and including a heat spreader ( 401 ), and a clip ( 50 ) fastening the heat sink assembly ( 40 ) above the IC module ( 30 ). The IC module ( 30 ) comprises a substrate ( 301 ) and at least one die ( 302 ) attached on a top surface of the substrate ( 301 ). The clip (50) has a set of first fingers ( 504 ) for pressing the die ( 301 ) of the IC module ( 30 ) and a set of second fingers ( 505 ) for pressing the substrate ( 301 ) of the IC module ( 30 ).

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an electrical connector assembly, and more particularly to an electrical connector assembly, in which an IC module is evenly applied pressure force so as to prevent potential warpage thereof. 
   2. Background of the Invention 
   U.S. Pat. No. 5,722,848 issued to Lai on Mar. 3, 1998 discloses a typical connector socket, which is generally referred to a ZIF (Zero Insertion Force) socket. The socket includes a base with a plurality of terminals received therein, and a cover moveably attached to the base. A lever with a cam mechanism is arranged between the base and the cover at a front portion so as to actuate the cover to move between a first position and a second position. When the lever is located in a vertical position, the cover is kept at the first position, in which a number of through holes in the cover are completely in alignment with corresponding passageways in the base, Then the pin legs of an IC module can be inserted from the cover into the passageways without any engagement with the terminals. When the IC module is completely seated on the cover, the lever is then manually operated by a user to move from the vertical position to a horizontal position, and simultaneously actuates the cover to move from the first position to the second position. The IC module attached on the cover moves together with the cover and the pin legs thereof gradually contact with the terminals in the electrical socket. The electrical socket of Lai is commonly available for a desk-top computer. 
   The IC module socket that used on a notebook is substantially similar to that used on the desktop computer, and the only difference is that the lever in Lai is replaced by a screw configured with a cam feature. When the screw is rotated, the cover is actuated to move along the base, therefore the pin legs of the IC module are then in contact with the terminals in the base. 
   As rapid development of computer technology, the number of input/output (I/O) of the IC module is accordingly increasing as well. In order to increase the number of I/O, conductive pads are introduced to replace the pin-type legs so as to directly and electrically contact with the terminals in the socket. U.S. Pat. No. 7,001,197 issued to Shirai on Feb. 21, 2006 just discloses this type of IC socket, which can be generally called a LGA socket. 
   As clearly shown in the Figures of Shirai, this type of electrical socket has different configuration with that of Lai, and includes a metal stiffener enclosing an insulating housing, on which an IC module is disposed. A metal clip is pivotally assembled to one end of the stiffener, and a lever is pivotally assembled to the other end of the stiffener. When the clip is operated to a closed position with respect to the stiffener, the lever locks the clip. By this arrangement, the clip is able to tightly press the IC module toward the housing to ensure reliable electrical connection between the IC module and the socket. 
   Shirai is feasible to be applied on the desktop computer because there is enough space in the computer for the operation of the lever. However, it is almost impossible to be applied on the notebook, due to the small space limited by the contour of the notebook. 
   The IC module generally includes a substrate, and a die/dies on the substrate. Even the IC module is rigid, it is still likely to deform or warp if downward force applied thereon is not evenly distributed. 
   SUMMARY OF THE INVENTION 
   One object of the present invention is to provide an electrical connector assembly employing a clip to fasten a heat sink assembly. 
   Another object of the present invention is to provide a clip for providing pressure force evenly distributed to an IC module. 
   In order to achieve the first object, an electrical connector assembly made in accordance with a preferable embodiment of the present invention comprises an electrical socket with a plurality of contacts received therein, an IC module mounted onto the electrical socket so as to make electrical connection therebetween, a heat sink assembly pressing on the IC module and including a heat spreader, and a clip fastening the heat sink assembly above the IC module. The IC module comprises a substrate and at least one die attached on a top surface of the substrate. The clip has a set of first fingers for pressing the die of the IC module and a set of second fingers for pressing the heat spreader. 
   In order to achieve the second object, a clip made in accordance with a preferable embodiment of the present invention for pressing a heat sink assembly toward an IC module comprises a base portion, a set of first fingers extending from the base portion and having first free ends distributed at a relative periphery position, and a set of second fingers extending from the base portion and having second free ends distributed at a relative central position. The first free ends are not coplanar with the second free ends. 
   Other objects, advantages and novel features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which: 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded, isometric view of an electrical connector assembly according to a first embodiment of the present invention; 
       FIG. 2  is an assembled, isometric view of  FIG. 1 ; 
       FIG. 3  is an exploded, isometric view of an electrical connector assembly according to a second embodiment of the present invention; 
     FIG  4  is an assembled, isometric view of  FIG. 3 ; 
       FIG. 5  is an exploded, isometric view of an electrical connector assembly according to third embodiment of the present invention, in which the electrical socket and the IC module are not shown; and 
       FIG. 6  is an assembled, isometric view of  FIG. 5 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Embodiment A 
   Referring to  FIG. 1  to  FIG. 2 , an electrical connector assembly  100  in accordance with a first embodiment of the present invention includes an electrical socket  20  mounted on a PCB (printed circuit board)  10 , an IC module  30  disposed on the electrical socket  20 , a heat sink assembly  40  engaging with the IC module  30 , and a clip  50  securely attached to the PCB  10  for pressing the heat sink assembly  40  toward the IC module  30 . 
   The electrical socket  20  includes a rectangular base portion  201  and four side walls  202  extending integrally from the base portion  201  so as to together define an receiving cavity (not labeled) for the IC module  30 . A number of contacts (not shown) are mounted within the base portion  201  to establish electrical connection with the IC module  30 . 
   The IC module  30  includes a substrate  301  and a pair of dies  302  disposed on the substrate  301 . The heat sink assembly  40  comprises a heat spreader  401  and a pair of heat pipes  403 . The heat spreader  401  has two slots  402  at the bottom thereof respectively for receiving the heat pipes  403 . The slots  402  extend through a bottom surface of the heat spreader  401  so as to allow the heat pipes  403  to directly touch the dies  302  of the IC module  30 . 
   The clip  50 , capable of being secured to the PCB  10 , is provided to press the heat sink assembly  40  toward the IC module  30 . The clip  50  comprises a substantial rectangular base portion  501 , four legs  502  extending from corners of the base portion  501  and having holes  503  adapted to engage with screws (not shown) to secure the clip  50  to the PCB  10 . A set of first fingers  504 , for pressing the substrate  301  of the IC module  30 , extend outward and downward integrally from four periphery edges of the base portion  501 , and each of these first fingers  504  is formed with a first free end  5041  which directly engages with the substrate  301  of the IC module  30 . A set of second fingers  505 , for pressing the heat spreader  401 , extend inward and downward integrally from a substantial central position of the base portion  501 , and each of these second fingers  505  is formed with a second free end  5051  which directly engages with the heat spreader  401 . Apparently, the first free ends  5041  are non-coplanar with the second free ends  5051 , and the height difference between the first free ends  5041  and the second free ends  5051  is accurately dimensioned corresponding to the stack height of the die  302  and the heat spreader  401 , so that the dies  302  and the substrate  301  of the IC module  30  are simultaneously exerted pressure force, respectively from the heat sink assembly  40  and the first fingers  504 . In other words, the pressure force evenly distributed is provided to be applied onto the IC module  30  and therefore the potential warpage of the IC module  30  is prevented. 
   Embodiment B 
   Referring to  FIG. 3  and  FIG. 4 , in this second embodiment, an electrical connector assembly  200  is provided to include an electrical socket  20 , an IC package  30  to be seated on the electrical socket  20 , a heat sink assembly  70 , and a clip assembly  60  employed to secure the heat sink assembly  70 . The electrical socket  20  and the IC module  30  have the same structure as that in the first embodiment, and details of which are not repeatly described herein. 
   The clip assembly  60  includes a first clip  601  and a pair of second clips  602 . The second clips  602  are arranged opposite to each other and located under two ends of the first clip  601 . The first clip  601  has three parallel spring beams  6011 , each of which is formed with a recessed pressing portion  6013  at a central position thereof, and a pair of mounting portion  6012  formed at opposite ends of the spring beams  6011  and perpendicular to the spring beams  6011 . Among these three parallel spring beams  6011 , the one at the middle position has two securing holes  6014  respectively formed at two ends thereof, and correspondingly, a pair of securing holes  6015  are respectively formed on the mounting portions  6012  as well. The second clip  602  has a mounting portion  6021  formed with three mounting holes  6022 , and a pair of clipping portions  6023  extending from the mounting portion  602 . Among the three mounting holes  6022  on the second clip  602 , the central one is in alignment with the securing holes  6014 ,  6015  of the first clip  601 , so as to facilitate screws (not shown) to mount the clip assembly  60  to a PCB. 
   The heat sink assembly  70  comprises a pair of heat pipes  701  and a heat spreader  702  under the heat pipes  701 . The heat pipes  701  can be attached to the first clip  601  by interferencely engaging with two neighboring spring beams  6011  and positioning therebetween. Besides, soldering method is also feasible for securing the heat pipes  701  to the first clip  601 . The pressing portions  6013  press on the heat spreader  702 , which farther directly presses on the dies of the IC module  30 . Simultaneously the clipping portions  6023  of the second clips  602  press on the substrate of IC module  30  so that the dies and the substrate of the IC module  30  are simultaneously exerted pressure force, respectively from the heat sink assembly  70  and the second clip  602 . In other words, the pressure force evenly distributed is provided to be applied onto the IC module  30  and therefore the potential warpage of the IC module  30  is prevented. 
   Embodiment C 
   An electrical connector assembly  300  as a third embodiment is illustrated in  FIG. 5  and  FIG. 6 , in which the electrical socket and the IC module that have the same structures as that described the first and the second embodiments, are omitted in  FIG. 5  and  FIG. 6 . In this embodiments the clip assembly  90 , provided to secure a heat sink assembly  80 , includes a clip  901  and a loading frame  902 . The clip  901  has two pairs of recessed pressing portions  9011  extending downward from two opposite edges thereof. The loading frame  902  has a pair of row edges  9021  and there parallel column beams  9022  perpendicular to the row edges  9021 . Each of the column beams  9022  is formed with an elevated portion  9023 . The heat sink assembly  80  includes a pair of heat pipes  801  adapted to be located on the recessed pressing portions  9011  of the clip  901 , and a heat spreader  802  positioned under the clip  901  and between the two pairs of the recessed pressing portions  9011 . When the heat sink assembly  80  is in an assembled state, the recessed pressing portions  9011  abut against the row edges  9021  of the loading frame  902 , and then the loading frame  902  directly press on the substrate of the IC package. The elevated portions  9023  are lifted up to abut against the heat spreader  802 , and are dimensioned to allow the dies of the IC module to accurately touch the heat spreader  802 . Therefore, the dies and the substrate of the IC module are simultaneously exerted pressure force, and potential warpage of the IC module is thereby prevented. 
   While preferred embodiments in accordance with the present invention have been shown and described, equivalent modifications and changes known to persons skilled in the art according to the spirit of the present invention are considered within the scope of the present invention as defined in the appended claims.