Abstract:
A method and apparatus for loading IC&#39;s into a socket lid is disclosed. The IC is first loaded into a lid. Once the IC has been loaded into the lid, the lid is rotated into a closed position on the frame. The lid is then locked in place on the frame by rotating at least one locking lever into a closed lacked position, where the locking lever forces the lid down against the socket contacts against a spring.

Description:
BACKGROUND 
       [0001]    Many integrated circuits (IC) are mounted to a printed circuit (PC) board using a socket. One type of socket is a land grid arrays (LGA) socket. Older style sockets have holes in the socket that mate with pins attached to the underside of an IC. LGA sockets have protruding pins or spring contacts which touch contact pads on the underside of an IC. LGA sockets typically do not require any insertion force when installing the IC into the socket. The IC is held into the socket against the spring contacts by a lid. The lid is clamped in place once the IC has been loaded into the socket. 
         [0002]    Aligning and inserting or removing the IC from the socket can be difficult. Many ICs have special tools designed to assist the insertion of the IC into the socket. Even using the special tool the spring contacts may be damaged when the IC is being inserted or removed from the socket. When the spring contacts in the socket become damaged, the socket must be replaced. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0003]      FIG. 1A  is an isometric top view of a detachable lid assembly  100  in an example embodiment of the invention. 
           [0004]      FIG. 1B  is an isometric top view of a socket bottom  150  in an example embodiment of the invention. 
           [0005]      FIG. 1C  is an isometric top cutaway view of socket assembly  180  in an example embodiment of the invention. 
           [0006]      FIG. 1D  is an isometric top view of a section of a detachable lid assembly in an example embodiment of the invention. 
           [0007]      FIG. 2A  is an isometric top view of a socket assembly  290  in an example embodiment of the invention. 
           [0008]      FIG. 2B  is a close-up isometric view of the spring loading part of socket assembly  290 . 
           [0009]      FIG. 2C  is an isometric top view of detachable lid assembly  200  in an example embodiment of the invention. 
           [0010]      FIG. 2D  is an isometric bottom view of detachable lid assembly  200  in an example embodiment of the invention. 
           [0011]      FIG. 3(A-C)  is a pictorial representation for the assembly steps of a socket assembly in an example embodiment of the invention. 
           [0012]      FIG. 4A  is an isometric top view of a socket assembly  490  in as example embodiment of the invention. 
           [0013]      FIG. 4B  is an isometric top view of independent detachable IC holder  480 , in an example embodiment of the invention. 
           [0014]      FIG. 4C  is an isometric bottom view of independent detachable IC holder  480 , in an example embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]      FIGS. 1-4  and the following description depict specific examples to teach those skilled in the art how to make and use the best mode of the invention. For the purpose of teaching inventive principles, some conventional aspects have been simplified or omitted. Those skilled in the art will appreciate variations from these examples that fall within the scope of the invention. Those skilled in the art will appreciate that the features described below can be combined in various ways to form multiple variations of the invention. As a result, the invention is not limited to the specific examples described below, but only by the claims and their equivalents. 
         [0016]    In one example embodiment of the invention, an LGA socket will have a spring loaded lid. The spring loaded lid may have a bracket attached to the lid. The IC will be mounted into the lid/bracket. The spring will force the lid away from the contacts in the socket until a locking lever is moved into a closed position. Because the spring loaded lid is force away from the socket contacts, damage to the contacts in the socket may be reduced. 
         [0017]      FIG. 1A  is an isometric top view of a detachable lid assembly  100  in an example embodiment of the invention. Detachable lid assembly  100  comprises lid  102 , bracket  104  and integrated circuit (IC)  106 . Lid  102  is typically fabricated from a stiff material, for example metal. Bracket  104  is fabricated from a flexible material, for example Thermal Plastic Polyurethane (TPU). IC  106  may be any type of semiconductor device, for example a CPU, an application specific integrated circuit (ASIC), a memory device, or the like. Lid  102  has at least one tongue  108  that extends from one side of lid  102 . Lid  102  has hinge pin  110  attached to lid  102  on the opposite side from tongue  106 . 
         [0018]      FIG. 1B  is an isometric top view of a socket bottom  150  in an example embodiment of the invention. Socket bottom  150  comprises frame  152 , two locking levers ( 154   a  and  154   b ), socket contacts  156  and spring  164 . Socket bottom  150  is attached to PC board  168  with screws  158 . In some example embodiments of the invention, a stiffener plate (not shown) maybe used on the bottom side of PC board  168  capturing PC board  168  between the stiffener plate and the frame  152 . The PC board  168  may be the mother board for a personal computer, the processor board of a blade, the memory board of a memory system, or the like. 
         [0019]    A U-shaped tab  162  is formed at one end of frame  152 . The inside of U-shaped tab  162  forms a pivot channel that males with hinge pin  110  on lid  102 . A pivot channel is a structure that allows the hinge pin to move vertically with respect to the frame, but restricts horizontal motion of the hinge pin. In addition the pivot channel allows the hinge pin to rotate inside the pivot channel about the long axis of the hinge pin. During assembly, the detachable lid assembly is positioned at an angle with respect to socket base  150  with the hinge pin closest to the socket base. The hinge pin  110  is then snapped into the U-shaped tab on the frame  152 . When detachable lid  102  is snapped into socket base  150 , hinge pin  110  fits into the pivot channel (inside the curved section of U-shaped tab  162 ). Spring  164 , forces hinge pin  110  against the top of the pivot channel. The width X′ of U-shaped tab  162  fits inside the gap X of hinge pin  110 . In one example embodiment of the invention, the position of hinge pin  110  with respect to the pivot channel is used to align IC  106  to the socket contacts  156 . In other embodiments, the IC may be aligned to the socket contacts  156  by one or more edges surrounding socket contacts  156 . Once the detachable lid  102  has been snapped into the frame, the lid  102  can be rotated, inside the pivot channel, onto the socket bottom  150 . In the open position detachable lid  102  will make an angle of between 45 and 115 degrees with respect to the socket contacts. The two locking levers can then be rotated from the open position into the closed position. As the locking levers are rotated into the closed position, locking bars  160   a  and  160   b  mate with the lid  102  and force the IC mounted in the lid  102  against the socket contacts  156 . 
         [0020]      FIG. 1C  is an isometric top cutaway view of socket assembly  180  in an example embodiment of the invention. Socket assembly  180  comprises detachable lid  102 , IC  106 , frame  152 , spring  164 , screws  158 , locking lever  154   b  and locking bars  160   a  and  160   b.    FIG. 1C  shows detachable lid  102  in the closed position with both locking levers in the closed position. Locking bar  150   b  is shown forcing tongue  108  downward, and locking bar  160   a  is shown forcing hinge pin  110  downward. Before locking lever  154   a  (see  FIG. 1   b ) is rotated into the closed position, looking bar  160   a  does not force hinge pin  110  downwards. Therefore when locking lever  160   a  is in the open position, spring  164  keeps hinge pin  110  pressed against the top of the pivot channel. When locking lever  154   a  (see  FIG. 1   b ) is rotated into the closed position, locking bar  160   a  forces hinge pin  110  downwards by distance d, forcing the underside of IC  106  against the socket contacts  156 . In one example embodiment of the invention distance d is between 0.5-3.5 mm. Distance d may be 2.4 mm. 
         [0021]    Because spring  164  keeps hinge pin  110  up against the top of the pivot channel until locking lever is rotated into the closed position, the bottom surface of IC  106  may not make contact with socket contacts  156  until IC  106  is properly aligned with the socket contacts  156 . In one embodiment of the invention, the bottom surface of the IC may not touch the socket contacts when the hinge pin is at the top of the pivot channel and the lid is in the closed position. In other embodiment, the bottom surface of the IC may be resting on, or slightly compressing, the socket contacts when the hinge pin is at the top of the pivot channel and the lid is in the closed position. In one example embodiment of the invention, the force acting against hinge pin  110  by spring  164  is between 1 lbs and 3 lbs when the hinge pin is at the top of the pivot channel, and between 6 lbs and 10 lbs when the hinge pin is at the bottom of the pivot channel. The spring force may be 2 lbs when the hinge pm is at the top of the pivot channel, and 7 lbs when the hinge pin is at the bottom of the pivot channel. In some example embodiments the spring force is supplies by two springs. In one example embodiment, the lid  200  may not be detachable, but may be permanently attached to the socket frame. 
         [0022]    In another example embodiment of the invention, hinge pin  110  may not be cylindrical in shape.  FIG. 1D  is an isometric top view of a section of a detachable lid assembly in another example embodiment of the invention. Hinge pin  110  in  FIG. 1D  is not a separated cylindrical part held by tabs of the lid  102 . Hinge pin  110  in  FIG. 1D  is formed as part of the sheet metal of lid  102  and comprises a flat section of length X. When detachable lid  102  is snapped into socket base  150 , the flat hinge pin  110  fits into the pivot channel (inside the curved section of U-shaped tab  162 ). Spring  164 , forces hinge pin  110  against the top of the pivot channel. The width X′ of U-shaped tab  162  fits inside the gap X of hinge pin  110 . The flat hinge pin is able to move vertically with respect to the frame, but is restricted in horizontal motion. In addition the pivot channel allows the flat hinge pin to rotate inside the pivot channel about the long axis of the hinge pin. 
         [0023]    In another example embodiment of the invention, the lid may be divided into two parts: a detachable part and a spring loaded part.  FIG. 2A  is an isometric top view of a socket assembly  290  in an example embodiment of the invention. Socket assembly  290  comprises: frame  252 , screws  258 , socket contacts  256 , two locking levers  254   a  and  254   b,  detachable lid  200 , spring loaded lid  270  and IC  206 .  FIG. 2   a  shows detachable lid  200  detached from spring loaded lid  270  with IC  206  ready to be installed into detachable lid  200 . Spring loaded lid  270  is shown in the open position making an angle of approximately 95 degrees with respect to socket contacts  256 . 
         [0024]      FIG. 3(A-C)  is a pictorial representation for the steps used to assemble a socket assembly in an example embodiment of the invention. At step one ( FIG. 3   a ) the IC is loaded into the detachable lid. At step  2  ( FIG. 3   b ) the detachable lid is inserted into the spring loaded lid while the spring loaded lid is in its open position. Spring loaded lid makes a large angle (45-115 degrees) with respect to socket contacts  256  when in the open position. At step  3  ( FIG. 3   c ) the two part lid (the detachable lid and the spring loaded lid) is rotated down onto the socket bottom (as shown by arrow  1 ). At step  4  ( FIG. 3   c ) the lower locking lever is rotated into its closed position (shown by arrow  2 ), thereby capturing tongue  208  and forcing one end of the IC mounted in the two part lid down against the socket contacts. At step  5  ( FIG. 3   c ) the upper locking level is rotated into its closed position (as shown by arrow  3 ), compressing springs  264  and pushing hinge pin  210  down in the pivot channel, thereby forcing the other end of IC mounted in the two part lid down against the socket contacts. 
         [0025]    The two locking levers are installed into frame  252  with one locking lever 
         [0026]    mounted at each end of frame  252  (see  FIG. 2   a ). Each locking lever ( 254   a  and  254   b ) has a locking bar  260   a  and  260   b.  Locking bar  260   a  is shows in front of spring loaded lid  270  (for clarity). In actual operation, locking bar  260   a  is located behind spring loaded lid  270  (as shown in  FIG. 2   b ). Both locking levers ( 254   a  and  254   b ) can be rotated between an open position and a closed position. Both locking levers are shown in the open position in  FIG. 2   a.  When locking lever  254   b  is rotated into its closed position, locking bar  260   b  captures tongue  208 , forcing detachable lid downward. When locking lever  254   a  is rotated into its closed position, locking bar  260   a  forces spring loaded lid downward. 
         [0027]      FIG. 2B  is a close-up isometric view of the spring loading part of socket assembly  290 . A hinge pin  210  is attached to one end of spring loaded lid  270 . Hinge pin  210  is captured inside slots formed in two parallel tabs  262  bent vertically from frame  253 . The two slots form a pivot channel. A pivot channel is a structure that allows the hinge pin to move vertically with respect to the frame, but restricts horizontal motet of the hinge pin. In addition the pivot channel allows the hinge pin to rotate inside the pivot channel about the cylindrical axis of the hinge pin. At least one spring  264  is attached to hinge pin  210  and pushes against the bottom of socket assembly  290 , forcing hinge pin  210  up into the top of the pivot channel. Hinge pin  210  can move distance d downwards inside the pivot channel by compressing spring  264 . Hinge pin  210  is free to rotate around its cylindrical axis inside pivot channel. Locking lever  254   a  is shown in the open position with locking bar  260   a  behind spring loaded lid. 
         [0028]      FIG. 2C  is an isometric top view of detachable lid assembly  200  in an example embodiment of the invention.  FIG. 2D  is an isometric bottom view of detachable lid assembly  200  in an example embodiment of the invention. Detachable lid assembly  200  comprises lid  202 , IC holder  280 , and 2 stiffeners  284 . Lid  202  is fabricated from a stiff material, for example metal. Lid  202  has tongue  208  formed at one end IC holder  280  is attached to lid  202 . Stiffeners  284  are attached to IC holder with IC holder in-between the lid and the stiffeners (see  FIG. 2   d ). IC holder is formed to retain an IC inserted into IC holder. In one embodiment, IC holder  280  may be fabricated from a flexible material and uses an interference, fit to retain the IC in another embodiment, the IC may snap into IC holder  280  and be retained by the snap features in IC holder  280 . 
         [0029]    Detachable lid is configured to be inserted into the spring loaded lid  270 . Stiffeners  284  mate with channels formed in the spring loaded lid, allowing the detachable lid to be slid into the spring loaded lid. IC holder may have 2 “click” detents  282  formed in the top surface of IC holder  280 , one on each side. The “click” detents  282  snap into corresponding features in the spring loaded lid  270  to let a user know when the detachable lid has been fully inserted into the spring loaded lid  270 . By depressing the “click” features, detachable lid can be removed from the spring loaded lid. 
         [0030]    In another example embodiment of the invention, the spring loaded lid may have an independent detachable IC holder that slides into the lid when the lid is in the open position.  FIG. 4A  is an isometric top view of a socket assembly  490  in an example embodiment of the invention. Socket assembly  490  comprises: frame  452 , screws  458 , socket contacts  456 , two locking levers  454   a  and  454   b , independent detachable IC holder  480 , spring loaded lid  402  and IC  406 .  FIG. 4A  shows independent detachable IC holder  480  detached from spring loaded lid  402  and ready to be installed into spring loaded lid  402  (as shown by arrows). IC is shown loaded into the independent detachable IC holder  480 . Spring loaded lid  402  is shown in the open position making an angle (between 45 and 115 degrees) with respect to socket contacts  456 . In one example embodiment, when independent detachable IC holder  480  is slid into spring loaded lid  402 , the edges of independent detachable IC holder  480  fit into channels in spring loaded lid. Independent detachable IC holder  480  may have features that snap into place and lock independent detachable IC holder  480  into spring loaded lid  402  when independent detachable IC holder  480  is fully installed. 
         [0031]      FIG. 4B  is an isometric top view of independent detachable IC holder  480 , in an example embodiment of the invention.  FIG. 4C  is an isometric bottom view of independent detachable IC holder  480 , in an example embodiment of the invention. In  FIG. 4B  two slide in detents  490  can be seen formed into the two sides of the independent detachable IC holder  480 . The two slide in detents interact with two pins  496  (one pin can be seen in  FIG. 4A ) formed in the two channels on spring loaded lid  402 . The two slide in detents “snap” into place when the independent detachable IC holder  480  is fully inserted into spring loaded lid  402 . Two friction stop features  492  are formed on the bottom side (see  FIG. 4C ) of independent detachable IC holder  480 . The friction stop features interact with the two channels formed in spring loaded lid to hold the independent detachable IC holder  480  into the spring loaded lid. 
         [0032]    In one example embodiment, IC  406  will be loaded into independent detachable IC holder before the IC is provided to a user. In another example embodiment, IC  406  will be loaded into independent detachable IC holder when IC is loaded into socket assembly  490 . Independent detachable IC holder is formed to retain an IC inserted into the independent detachable IC holder. In one embodiment, independent detachable IC holder  280  may be fabricated from a flexible material and uses an interference fit to retain the IC. In another embodiment, the IC may snap into independent detachable IC bolder  280  and be retained by snap features in IC holder  280 . In another example embodiment of the invention, IC may be held in place using glue or epoxy. 
         [0033]    In some example embodiment of the invention, the spring loaded lid will be friction loaded such that the lid will be held in place at any angle between the open position and the closed position. In one example embodiment of the invention, the friction loading will be supplied by the interaction of the hinge pin against the pivot channel and the spring. The spring and the pivot channel remain stationary as the hinge pin rotates when the lid is rotated between the open position and the closed position. The spring pushes against the hinge pin creating friction between the hinge pin and the spring. The hinge pin is also forced against the top side of the pivot channel creating friction between the hinge pin and the pivot channel. The tolerance between the hinge pin and the spring and pivot channel, as well as the spring force of the spring, can be adjusted to hold the lid in place at any position between the open and closed position. 
         [0034]    In another example embodiment of the invention, the friction loading may be supplemented by the interaction of the tabs  262  and the ends of the hinge pin  210 . Tabs  262  may be bent slightly inward such that the distance between the tabs is smaller at the top of the pivot channel than at the bottom of the pivot channel. As hinge pin moves towards the top of the pivot channel the tabs  262  will act like springs holding the edges of lid  270  between them. The tolerance between the edges of lid  270  and the angle of the tabs  262 , can be adjusted to help hold the lid in place at any position between the open and closed position.