Abstract:
In one embodiment, the present invention includes a load frame to be affixed to a primary surface of a circuit board adjacent to a socket, a load plate having a proximal portion rotatably adapted to the load frame and a distal portion having a tongue member to be locked by a shoulder member adapted to the circuit board on a side of the socket opposite to the frame, and a load lever to mate the load plate to the load frame, where the load lever is rotatable from an open position to an engaged position to lock the tongue member of the load plate under a head of the shoulder member. Other embodiments are described and claimed.

Description:
BACKGROUND 
   Central processing units and similar integrated circuits communicate with other components of a computer system over a printed circuit board that is typically referred to as a mainboard or motherboard. Central processing units and similar processors are often coupled to the mainboard through a socket. The socket serves as an interface for the mainboard and central processing units. The socket aligns the interconnects of the central processing unit and the mainboard. The socket is coupled with a socket loading mechanism that electrically connects the central processing unit to the mainboard. 
   Typically, each socket has a loading mechanism designed especially for it, as variances in size, positioning, loading force and so forth require such specialized loading mechanisms. Furthermore, typical loading mechanisms can have a number of different parts, which raises the cost of developing and manufacturing these mechanisms, as well as attendant complexity during high volume manufacturing of computer systems including such sockets. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of an assembly in accordance with one embodiment of the present invention. 
       FIG. 2  is a side view of partial actuation of an intermediate load mechanism in accordance with an embodiment of the present invention. 
       FIG. 3A  is a side view of further actuation of an intermediate load mechanism in accordance with an embodiment of the present invention. 
       FIG. 3B  is a top view of a fully loaded intermediate load mechanism in accordance with an embodiment of the present invention. 
       FIG. 4A  is a close up view of an intermediate load mechanism in accordance with an embodiment of the present invention. 
       FIG. 4B  is another close up view of an intermediate load mechanism in accordance with an embodiment of the present invention. 
   

   DETAILED DESCRIPTION 
   In various embodiments, an intermediate load mechanism (ILM) is used to apply a preload on a processor to a socket. This preload is used to ensure electrical contact between the socket contacts and the processor package. Some embodiments may include four major components, namely, a load plate, a load lever, a frame and a backing plate. The load lever is the component to which a user applies a finger load to actuate movement into the load plate and eventually apply a resulting preload to the processor package, and more particularly to an integrated heat spreader (IHS), where present. Due to the design of both the lever and load plate there is a mechanical advantage that is produced, minimizing the load applied by the user and maximizing the resulting preload onto the processor IHS via the load plate. The frame is a piece of structure that assembles the load lever to the motherboard surface or other circuit board to which the retention mechanism is attached. In one embodiment, a plurality of screws or other such fasteners are used to fasten the frame to the backside stiffening plate through the circuit board. In turn, the backside stiffening plate is used to control the local warpage of the motherboard under the socket and provide solderball joints protection for dynamic and environmental effects. 
   Embodiments may enable a user to open and close the load plate to give access to the socket and to provide a preload, as mentioned above. The nature of the mechanism allows for a greater package thickness variation due to the kinematics of the design. This will allow for a larger number of processors (i.e., of varying different sizes) to be used with this load mechanism, which reduces assembly factory cost to limit dimensional shifting of the integrated heat spreader. The mechanism also allows a single actuation for opening/closing the load plate and applying the load. That is, the user only needs to interface with the load lever in a single movement to operate the mechanism. This further enables improved assembly feed rate during circuit board manufacture, such as during test operations. 
   Referring now to  FIG. 1 , shown is a perspective view of an assembly in accordance with one embodiment of the present invention. More specifically, as shown in  FIG. 1 , an intermediate load mechanism may be provided in connection with a processor package  20  coupled to a motherboard or other circuit board  10  via a socket  30 . In one embodiment, processor package  20  may include a package substrate to which is coupled to a processor die, over which is adapted an IHS. As shown in  FIG. 1 , the ILM includes a frame  40 . As will be described further below, frame  40  may be adapted to a primary surface of motherboard  10  by fasteners such as a pair of screws. Note that frame  40  is only adapted to be adjacent to a single side of a socket, rather than extending peripherally about the entire socket, reducing cost and footprint, minimizing an amount of board real estate consumed, as well as the number of fasteners needed to adapt it to circuit board  10 . In turn, a load plate  45  is adapted to frame  40  and is actuated by a load lever  50 . To enable support of the load generated by the ILM, a backing plate  60  may be provided on a secondary surface of motherboard  10 . Backing plate  60  may be retained using the fasteners that couple frame  40  to motherboard  10 . Still further, a shoulder screw  65  may be adapted on a side of socket  30  distal to frame  40 . As will be described further below, shoulder screw  65  may aid in mating and retaining load plate  45  in its retention position using a tongue  42  of load plate  45 . While shown with this particular implementation in the embodiment of  FIG. 1 , the scope of the present invention is not limited in this regard. 
   To assemble the ILM to circuit board  10 , first backing plate  60  may be adapted to the secondary surface of circuit board  10 . Shoulder screw  65  may be fastened in place to secure backing plate  60  to circuit board  10 . Then load plate  45  and load lever  50  may be assembled to frame  40 , as load lever  50  acts to mate load plate  45  to frame  40 . Finally, the combined subassembly including load plate  45 , load lever  50  and frame  40  may be installed onto circuit board  10 , e.g., using a pair of screws that further secure to backing plate  60 . 
   After adaptation of an ILM to a circuit board in accordance with an embodiment of the present invention, the ILM may be actuated to allow it to retain a processor package to its socket. Referring now to  FIG. 2 , shown is a side view of a partial actuation of an intermediate load mechanism in accordance with an embodiment of the present invention. As shown in  FIG. 2 , load lever  50  is partially actuated. A user may rotate load lever  50  in a counter clockwise manner. In so doing, load plate  45  touches the primary surface of circuit board  10  as its distal portion (with respect to frame  40 ) rotates in a downward manner. By the continual actuation of load lever  50 , the distal portion of load plate  45  clears the head of shoulder screw  65 , as shown in  FIG. 2 . As the user continues to rotate load lever  50 , it causes load plate  45  to then primarily translate in a horizontal direction (i.e., right to left in  FIG. 2 ) with some vertical translation. Tongue  42  of load plate  45  translates under the head of shoulder screw  65 . Note that tongue  42  may still touch the primary surface of circuit board  10 . 
   Referring now to  FIG. 3A , shown is a side view of further actuation of an intermediate load mechanism in accordance with an embodiment of the present invention. As shown in  FIG. 3A , the rotation of load lever  50  now causes primarily a vertical translation of load plate  45 . When load plate  45  touches the surface of processor package  20  (and more specifically an IHS of the package where present), the distal portion of load plate  45  is caused to lift up off the primary surface of circuit board  10 . In this way, tongue  42  (not shown in  FIGS. 2 and 3A ) contacts the head of shoulder screw  65 . A user may continue to rotate load lever  50  to a final position (e.g., at a horizontal level) with respect to  FIG. 3A  to apply an appropriate preload value. While the scope of the present invention is not limited in this regard, the preload compression may be between approximately 350 and 650 Newtons. 
     FIG. 3B , which is a top view of a fully loaded intermediate load mechanism in accordance with an embodiment of the present invention, shows that load lever  50  hooks into load plate  45  with this same rotational force (i.e., a single movement). A pair of tabs  47  on load plate  45  may center on a center line of the underlying socket. Furthermore, tongue  42  of load plate  45  interfaces the bottom of the head of shoulder screw  65 . Note in the embodiment of  FIG. 3B  that load plate  45  may have an oversized cutout to allow for desired translation. 
   In various embodiments, a series of cam interfaces may be provided to enable controlled actuation of a load plate in accordance with an embodiment of the present invention. More specifically, multiple cam interfaces may be present to control the rotation of the load plate relative to the rotation of the load lever. In this way, the load plate may be prevented from an undesired slamming shut. Furthermore, such features may allow for a single motion of the load lever to open and close the load plate, via a one-handed operation. 
   Referring now to  FIGS. 4A and 4B , shown are close up views of an intermediate load mechanism in accordance with an embodiment of the present invention. As shown in  FIG. 4A , load plate  45  includes a primary cam surface  46 . By presence of this cam surface, after load plate  45  has completed translating, it contacts the edge of frame  40  and load plate  45  is forced to rotate upwardly. Furthermore, ears  48  present on both sides of load plate  45  may pre-align load plate  45  prior to closing around the perimeter of a socket body. Referring also to  FIG. 4B , frame  40  may include a secondary cam surface  42 , which may provide the same function as the primary cam surface  46  after that cam runs out of travel. 
   An assembly in accordance with an embodiment of the present invention may be significantly cheaper than other retention mechanisms, as a reduced number of parts and lesser material are used in the assembly. Embodiments also accommodate a larger variation of package thickness, allowing for greater adoption and flexibility for those who choose to use this assembly. Embodiments may also improve flexibility of board routing, as only three fasteners are used, particularly as one of the fasteners is located away from a socket corner. The single actuation of the mechanism is in contrast to conventional solutions that require a user to disengage the load lever, then as a second step manually open the load lever. To apply an embodiment the user need only rotate the load lever to open the load plate and access the socket. The mechanism also allows easy access to the socket and processor because the load plate rotates away from the socket, and the entire socket is exposed. The end user can thus receive visual indicators for installing the package to the socket, leading to a more robust assembly process and an improved fallout rate. With full visual indication and single step actuation, less chance of pin damage in the socket can be realized. 
   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.