PATENT DOCUMENT

Publication Number: US-11398692-B2
Application Number: US-202017032488-A
Country: US
Kind Code: B2

Title: Socket with integrated flex connector

Abstract:
The connector portion of a flex connector may be integrated into a socket, by forming a complete cutout in the socket in which the connector is located, or by forming the socket with a portion having a reduced thickness relative to the rest of the socket, with the connector being positioned in this portion of reduced thickness between the socket and an MLB. Another flex connector may be formed vertically above the first flex connector, mounted to the top surface of the package and clamped in place by a heat sink on top of the stack. Providing both top and bottom flex connectors may multiply the number of available connections for a given footprint. A heatsink positioned on top of the stack may include a spring assembly on a bottom portion to engage specified portions of the stack with a predefined force to ensure correct loading.

Claims:
What is claimed is: 
     
       1. An electronic structure comprising:
 a multi-layer board (MLB) having a top surface; 
 a flex connector including a set of flex electrical connectors, the flex connector being positioned on said MLB top surface with said set of flex electrical connectors oriented away from said MLB; 
 a socket having a top surface and a bottom surface, the socket including a plurality of socket electrical connectors extending therethrough between said top and bottom surfaces; 
 wherein the socket includes a first portion with a first thickness between said top and bottom surfaces, and a void completely through a thickness of a second portion, wherein the flex connector extends through said void; 
 wherein the socket is positioned with said first portion in contact with said MLB, and a portion of said flex connector including said set of flex electrical connectors positioned within the void in the socket; and 
 a package positioned directly on said socket on a side of said socket opposite said MLB, wherein said package comprises a ledge portion directly contacting and in electrical communication with said flex connector. 
 
     
     
       2. The electronic structure in accordance with  claim 1 , wherein said flex connector includes a flexible printed circuit (FPC) and a connector portion. 
     
     
       3. The electronic structure in accordance with  claim 2 , wherein the connector portion includes the set of flex electrical connectors. 
     
     
       4. The electronic structure in accordance with  claim 1 , wherein said flex connector is a first flex connector, and further comprising:
 a second flex connector positioned vertically above said first flex connector and mounted to and in electrical communication with a surface of said package opposite said socket. 
 
     
     
       5. The electronic structure in accordance with  claim 4 , wherein said ledge portion comprises said surface of said package opposite said socket at which said package is in electrical communication with said second flex connector. 
     
     
       6. The electronic structure in accordance with  claim 4 , wherein:
 the package has an overall vertical thickness and comprises a package substrate having a vertical thickness less than the package overall vertical thickness; and 
 a combined vertical thickness of the second flex connector and of the package substrate is the same as the overall vertical thickness of the package. 
 
     
     
       7. The electronic structure in accordance with  claim 1 , wherein said package is a first package and said set of flex electrical connectors is a first set of electrical connectors located at a first end of said flex connector, and further comprising:
 a second package; and 
 a second set of flex electrical connectors located at a second end of said flex connector; 
 wherein said second set of flex electrical connectors is connected to said second package. 
 
     
     
       8. An electronic structure comprising:
 a multi-layer board (MLB) having a top surface and a plurality of board electrical connections; 
 a flexible printed circuit (FPC) including a set of flex electrical connectors, the FPC being positioned on said MLB top surface with said set of flex electrical connectors oriented away from said MLB; 
 a socket having a top surface and a bottom surface, the socket including a plurality of socket electrical connectors extending therethrough between said top and bottom surfaces; 
 wherein the socket includes a first portion with a first thickness between said top and bottom surfaces, and a second portion with a second thickness between said top and bottom surfaces, wherein said first thickness is greater than said second thickness; 
 wherein the socket is positioned with said first portion in contact with said MLB, and a portion of said FPC including said set of flex electrical connectors is positioned between said second portion and said MLB; 
 wherein a vertical thickness of said socket in said first portion is the same as a combined vertical thickness of the socket and the FPC in the second portion; and 
 wherein said set of flex electrical connectors is vertically aligned with at least some of said plurality of socket electrical connectors. 
 
     
     
       9. The electronic structure in accordance with  claim 8 , further comprising:
 a package positioned on and in electrical communication with said socket on a side of said socket opposite said MLB, said package directly contacting said socket in said second portion, and said socket directly contacting said flex connector in said second portion. 
 
     
     
       10. The electronic structure in accordance with  claim 8 , wherein the set of flex electrical connectors is a set of flex electrical connector pads, and the plurality of socket electrical connectors is a plurality of socket electrical connector pins. 
     
     
       11. The electronic structure in accordance with  claim 9 , wherein said FPC is a first FPC, and further comprising:
 a second flex connector including a second FPC and a second connector portion positioned vertically above said first FPC and mounted to and in electrical communication with a surface of said package opposite said socket. 
 
     
     
       12. The electronic structure in accordance with  claim 11 , wherein said package comprises a ledge portion comprising said surface of said package opposite said socket at which said package is in electrical communication with said second flex connector. 
     
     
       13. The electronic structure in accordance with  claim 9 , wherein said package is a first package and said set of flex electrical connectors is a first set of electrical connectors located at a first end of said FPC, and further comprising:
 a second package; and 
 a second set of flex electrical connectors located at a second end of said FPC; 
 wherein said second set of flex electrical connectors is connected to said second package. 
 
     
     
       14. The electronic structure in accordance with  claim 11 , wherein:
 the package has an overall vertical thickness and comprises a package substrate having a vertical thickness less than the package overall vertical thickness; and 
 a combined vertical thickness of the second flex connector and of the package substrate is the same as the overall vertical thickness of the package. 
 
     
     
       15. An electronic structure comprising:
 a multi-layer board (MLB) having a top surface; 
 a flex connector including a set of flex electrical connectors, the flex connector being positioned on said MLB top surface with said set of flex electrical connectors oriented away from said MLB; 
 a socket having a top surface and a bottom surface, the socket including a plurality of socket electrical connectors extending therethrough between said top and bottom surfaces; 
 wherein the socket includes a first portion with a first thickness between said top and bottom surfaces, and a second portion with a second thickness between said top and bottom surfaces, wherein said first thickness is greater than said second thickness; 
 wherein the socket is positioned with said first portion in contact with said MLB, and a portion of said flex connector including said set of flex electrical connectors positioned between said second portion and said MLB; 
 a heat sink positioned on a side of said socket opposite said MLB, the heat sink including
 a heat conducting body including at least one cavity; 
 at least one load controlling insert positioned in said at least one cavity and attached to said body; 
 wherein said load controlling insert is configured and arranged to variably control load transmitted through said insert from said body; 
 wherein said at least one load controller insert is a force control assembly comprising:
 a variable force generating member; and 
 walls defining a cavity, said variable force generating member being captured in said cavity between said walls and said heat conducting body. 
 
 
 
     
     
       16. The heat sink in accordance with  claim 15 , wherein said variable force generating member comprises a coil spring, a disc spring, wave spring, or polymer sleeve spring.

Description:
BACKGROUND 
     Field 
     Embodiments described herein relate to electronic packaging. More particularly, embodiments relate to sockets, flexible connectors, and heat sinks. 
     Background Information 
     When mounting a processor package to a printer circuit board (“PCB”) or multi-layer board (“MLB”), flexible connectors (commonly referred to as “flex connectors”) are often used to connect the processor package with other board components. The flex connectors extend laterally from the processor package, restricting the number of connections that can be made for any particular footprint. Also, when mounting a processor package to an MLB via a processor socket, typically a pair of screws are used, which can unevenly distribute the clamping forces. 
     SUMMARY 
     Embodiment are described of electronic packages and packaging processes including sockets including one or more integrated flex connector. In an embodiment, an electronic structure includes a multi-layer board (MLB) having a top surface, a flex connector including a set of electrical connectors, with the flex connector being positioned on said MLB top surface with said set of electrical connectors oriented away from said MLB, a socket having a top surface and a bottom surface, the socket including a plurality of electrical connectors extending therethrough between said top and bottom surfaces, wherein the socket includes a first portion with a first thickness between said top and bottom surfaces, and a second portion with a second thickness between said top and bottom surfaces, wherein said first thickness is greater than said second thickness, and wherein the socket is positioned with said first portion in contact with the MLB, and a portion of the flex connector including the set of electrical connectors positioned between said second portion and said MLB. 
     In some embodiments, the second thickness is zero thereby forming a void in the second portion, and the flex connector extends through the void. A package may be positioned on the socket on a side of the socket opposite the MLB, with the package directly contacting the said flex connector. The flex connector may be a first flex connector, and a second flex connector may be provided, positioned vertically above the first flex connector and mounted to and in electrical communication with a surface of the package opposite the socket. 
     In some embodiments, the package includes a ledge portion including the surface of the package opposite the socket at which the package is in electrical communication with the second flex connector. The package may have an overall vertical thickness and include a package substrate having a vertical thickness less than the package overall vertical thickness, and a combined vertical thickness of the second flex connector and of the package substrate may be the same as the overall vertical thickness of the package. 
     In embodiments, the package is a first package and the set of flex electrical connectors is a first set of electrical connectors located at a first end of the flex connector, and further including a second package, and a second set of electrical connectors located at a second end of the flex connector, wherein the second set of flex electrical connectors is connected to the second package. 
     In embodiments, the set of flex electrical connectors is vertically aligned with at least some of the plurality of socket electrical connectors. 
     A package may be positioned on and in electrical communication with the socket on a side of the socket opposite the MLB, with the package directly contacting the socket in the second portion, and the socket directly contacting the flex connector in the second portion. A vertical thickness of the socket in the first portion may be the same as the combined vertical thicknesses of the socket and the flex connector in the second portion. 
     A heat sink may be positioned on a side of the socket opposite the MLB. The heat sink may include a heat conducting body including at least one cavity, and at least one load controlling insert positioned in said at least one cavity and attached to said body, wherein the load controlling insert may be configured and arranged to variably control load transmitted through said insert from said body. The at least one load controlling insert may include at least one force control assembly. 
     An at least one force control assembly may include a variable force generating member, and walls defining a cavity, and the variable force generating member may be captured in the cavity between the walls and the heat conducting body. In embodiments, the variable force generating member may include a coil spring, a disc spring, a wave spring, or a polymer sleeve spring. The at least one force control assembly may include a fastener connecting the at least one force control assembly to the heat conducting body. 
     The fastener may include a screw having a screw thread, and the heat conducting body may include a bore having a matching screw thread, in which force transmitted by the at least one force control assembly is adjustable by adjusting the screw relative to the bore in the body. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Inventions of the present disclosure will now be described in more detail with reference to exemplary embodiments of apparatus and methods, given only by way of example, and with reference to the accompanying drawings, in which: 
         FIG. 1  illustrates an exploded perspective view of an embodiment of electronic components to be mounted to an MLB; 
         FIG. 2  illustrates an enlarged view of the embodiment of  FIG. 1 ; 
         FIG. 3A  illustrates a top plan view of the embodiment of  FIG. 1 ; 
         FIG. 3B  illustrates a cross-sectional view taken at line A-A in  FIG. 3A ; 
         FIG. 3C  illustrates a highly enlarged view of a portion of the cross-section of  FIG. 3B ; 
         FIG. 4  illustrates an exploded perspective view of another embodiment of electronic components to be mounted to an MLB; 
         FIG. 5  illustrates a highly enlarged view of a portion of a cross-sectional view of the embodiment of  FIG. 4 , in a view similar to that of  FIG. 3C ; 
         FIG. 6A  illustrates an exemplary embodiment of a process of assembling electronic components; 
         FIG. 6B  illustrates a process flow chart for the process of  FIG. 6A ; 
         FIG. 7A  illustrates another exemplary embodiment of a process of assembling electronic components; 
         FIG. 7B  illustrates a process flow chart for the process of  FIG. 7A ; 
         FIG. 8  illustrates a top plan view of an intermediate operation of assembling multiple sets of electronic subcomponents on a single MLB; 
         FIG. 9A  illustrates a bottom plan view of an embodiment of a heat sink; 
         FIG. 9B  illustrates a cross-sectional view taken at line C-C of the embodiment of  FIG. 9A ; 
         FIG. 9C  illustrates a cross-sectional view similar to  FIG. 3B , with a heat sink of  FIG. 9A  positioned at the top of a stack of components; and 
         FIG. 10  illustrates a highly enlarged cross-sectional view of a portion of  FIG. 9C . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the drawing figures, like reference numerals designate identical or corresponding elements throughout the several figures. 
     The singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a processor” includes reference to one or more of such processors. 
     In various embodiments, description is made with reference to figures. However, certain embodiments may be practiced without one or more of these specific details, or in combination with other known methods and configurations. In the following description, numerous specific details are set forth, such as specific configurations, dimensions and processes, etc., in order to provide a thorough understanding of the embodiments. In other instances, well-known packaging techniques have not been described in particular detail in order to not unnecessarily obscure the embodiments. Reference throughout this specification to “one embodiment” means that a particular feature, structure, configuration, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrase “in one embodiment” in various places throughout this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, configurations, or characteristics may be combined in any suitable manner in one or more embodiments. 
     The terms “over”, “to”, “between”, and “on” as used herein may refer to a relative position of one layer with respect to other layers. One layer “over”, or “on” another layer in “contact” with another layer may be directly in contact with the other layer or may have one or more intervening layers. One layer “between” layers may be directly in contact with the layers or may have one or more intervening layers. 
     In one aspect, embodiments described herein may include a flex connector integrated into a socket. For example, the socket may be a package socket for connecting a package such as a processor package to an MLB, such as a PCB. Such integration may allow for high speed signals to escape from the package substrate through the socket into the flex connector, which may enable lower power and/or signal loss, instead of through the MLB. A hybrid socket as described herein, which may include two different contacts in one housing, may eliminate the need for a separate specific flex connector to interface with the package substrate. Such a hybrid socket may also allow for better package substrate-to-socket contact registration, at least because a first socket portion to provide electrical communication between the package substrate and MLB, and a second socket portion to provide electrical connection between the package substrate and flex connector, may be formed as a single component, e.g., an injection molded component. 
     In another aspect, embodiments described herein may include a topside flex connector, in which a flex connector may be integrated on a top side of a package substrate, which may allow for a higher density (e.g., IO count) product in the same footprint as prior devices not including a topside flex connector. High speed signals escaping through a topside flex connector on a top routing layer in a package substrate may have much lower loss, as they may not encounter core/plated-through hole (PTH) vias in the package substrate or MLB and may be routed in a lower loss flex connector instead of a MLB with more loss. For a given IO count, deploying both the topside and the bottom side flex connectors may result in significantly shorter signal trace lengths on the package for both the top and bottom routed flex connectors. These shorter trace lengths may further reduce the trace losses as the package, as trace loss per unit length is greater than that of the flex or MLB. 
     In yet another aspect, embodiments described herein may include a compression mechanism for a microprocessor stack. As a socketed product may require a heatsink and compression to establish contact between a package, a socket, and an MLB, the same heatsink may include helical spring loaded pedestals which can align with the a topside flex connector and provide requisite loading to maintain the connector in contact with the package. 
       FIG. 1  illustrates a first exemplary embodiment of an electronic structure  100  implementing a socket having an integrated flex connector.  FIG. 1  illustrates a heat sink  102 , which may overlay a package  104 . The package  104  may in turn overlay and be in electrical communication with a socket  106 . The socket  106  may in turn overlay and be in electrical communication with a multi-layer board (MLB)  108 , which may be a PCB. Each of the heat sink  102 , package  104 , socket  106 , and/or MLB  108  may include alignment features  110 , which may be any known alignment features such as pegs and holes, which align adjacent components to predetermined orientations so that the combination of components can function. Fasteners  111  may also be provided to extend from below MLB  108 , through one or more of the socket and package, and into and/or through the heat sink  102 . Fasteners  111 , which may be screws, rivets, or the like, function to compress the components between the heat sink  102  and the MLB  108 , via nuts or the like (not illustrated) on ends of the fasteners. 
       FIG. 1  also illustrates an upper flex connector  112  positioned to make electrical connections with top portions of package  104 , and a lower flex connector  114  positioned to make electrical connections with lower portions of package  104  through a cutout in socket  106 . 
       FIG. 2  illustrates an enlarged view of portions of  FIG. 1 . Socket  106  includes a void or cutout  116  formed by sidewalls  118 , which may include a first sidewall  122  and intersecting sidewalls  120 . Cutout  116  may have a side opening  124 , or may include another first sidewall  122  which also intersects with sidewalls  120  to form a closed hole (not illustrated). Flex connector  114  may include a connector portion  126  which may include a set of electrical connectors  171  (see, e.g.,  FIGS. 6A, 7A ) oriented away from the MLB  108 , and a conducting flexible portion  128 , which may include one or more electrical routing layers to conduct electrical signals from the connector portion  126  and through the flexible portion  128 . It is to be appreciated that while the flexible portion  128  is shown as terminating, this section can extend from a first connector portion  126  at one end to a second connector portion  126  at a second end to connect between two sockets  106  and packages  104 . Similarly, the upper flex connector  112  can also include a flexible portion between two connector portions to connect between two sockets and packages. 
     Cutout  116  is sized and configured so that at least connector portion  126  of flex connector  114  extends vertically through the cutout of the socket  106  and makes electrical contact with overlying portions of package  104 , when the package, socket, flex connector, and MLB  108  are pressed together.  FIG. 2  also illustrates fasteners  111  and alignment features  110 . The flex connector  114  may be attached to the MLB  108  before the flex connector is connected to the package  104 , or the flex connector  114  may be attached to the MLB after the flex connector is connected to the package. The flex connector  114  may be held in place on the MLB  108  by a low strength mechanism, which may include magnets, low strength adhesive, or the like, between the flex connector and the MLB, which may facilitate the assembly process. Locator features (not illustrated) between flex connector  114  and MLB  108  may be provided, and may include clearance fit pegs and holes, in addition to the low strength mechanism. Flex connector  114  may also include a precise alignment feature with an overlying package substrate portion of the package  104 , which may be molded into the connector (e.g. a peg), and a vertically aligned through hole may be formed in the package substrate that can hold the flex connector in place until compression hardware is installed, such as that described in greater detail elsewhere herein. 
       FIGS. 3A-3C  illustrate several additional views of electronic structure  100 .  FIG. 3A  illustrates a top plan view of a stack including package  104 , socket  106 , and MLB  108 , including upper flex connector  112 .  FIG. 3B  illustrates a cross-sectional view taken at line A-A of  FIG. 3A , and  FIG. 3C  illustrates portion B from  FIG. 3B . In the implementation of  FIG. 3C , MLB  108  may be positioned at the bottom of a stack. Socket  106  overlies MLB  108  and is in electrical communication with the MLB. Lower flex connector portion  126 , with its connected flexible portion  128 , may be positioned in the cutout of the socket  106 , as illustrated in  FIGS. 1 and 2 , with the top surface of the portion  126  being at the same height as top portions of the socket  106 . Package substrate  105  of package  104  may overlie both socket  106  and portion  126  and make electrical connections therewith. Upper flex connector  112  may overlie package substrate  105  and make electrical connections therewith, at connector portion  200 . Thus, within the same footprint of a package  104 , multiple flex connectors may be vertically stacked, and may make electrical connections with different sides of the same package. Flex connector  112  may further be laterally separated from a compartment portion  158  of package  104 , providing a gap  155 , or may form an interference fit therewith. For example, compartment portion  158  may be a lid, or molding layer over one or more dies and/or components. For example, the compartment portion  158  may include one or more systems or sub-systems of the package  104 . 
       FIG. 4  illustrates a second exemplary embodiment of an electronic structure  150  including a socket having an integrated flex connector.  FIG. 4  illustrates a heat sink  102 , package  104 , and MLB  108 , with upper flex connector  112  and lower flex connector  114 , which may be substantially similar to those described and illustrated with reference to  FIGS. 1-3C . Electronic structure  150  may include a socket  152  which may be similar in some respects to socket  106 , but includes a trench or cutout portion  153 , demarcated by a line in the drawing, which is not entirely through a thickness of the socket and is thus different from cutout  116 . Instead, cutout portion  153  forms a shelf on the bottom surface of the socket  152  in which the connector portion of flex connector  114  may be positioned. Cutout portion  153  may otherwise be substantially similar to cutout portion  116 . 
       FIG. 5  illustrates a cross-sectional view through an electronic structure  150 , and shows heat sink  102 , package  104 , which may include compartment portion  158  and package substrate  105 , socket  152 , lower flex connector  114 , and MLB  108 , which may be stacked together and electrically interconnected as described elsewhere herein. In the intermediate embodiment of  FIG. 5 , upper flex connector  112  is optionally not included, or may be included but out of the plane of the cross-sectional view. Socket  152  may include a plurality of electrical conductors extending vertically therethrough, which may be socket spring pins  159 , and which may provide electrical communication between package  104  and MLB  108 . One or more of socket spring pins  159  may be located in cutout portion  153  and may provide electrical communication between package  104  and flex connector  114 , a portion of which may be located in the shelf portion of the socket  152 . Socket  152  thus defines at least two portions  154 ,  156 . A first portion  154  has a first thickness  155  between upper and lower surfaces of socket  152 , and may provide electrical communication between package  104  and MLB  108 . A second portion  156 , which corresponds to a linear portion of cutout  153 , is thinner than portion  154 , e.g., has a second thickness  157  that is less than the first thickness by an amount which may be equal to the vertical thickness of a connector portion of flex connector  114  that is captured between socket  152  and MLB  108 . Socket spring pins  159  in the portion  156  may thus be shorter than the socket spring pins  159  in portion  154 . Providing socket  152  with cutout portion  153  may permit use of standard flex connectors to make electrical connections through the socket with a package  104 , without requiring adaptation of the package&#39;s external electrical connections to match those of the flex connector. 
       FIGS. 6A and 6B  together illustrate and describe an embodiment of a process of assembling a stack of components. With reference first to  FIG. 6A  alone, the stack may include: an upper compression member, which may be a heat sink  102 ; package  104 , including a lower surface  160  including electrical connectors  163 ; socket  152 , which may include shelf  161  on a bottom portion as described elsewhere herein, and having an upper surface  172  and a bottom surface  174 ; lower flex connector  114 , which may include a top surface  166  including electrical connectors  171 , and a bottom surface  164 ; and MLB  108 , which may include a top surface  162  having electrical connections  165  thereon. 
     With reference to both  FIG. 6A  and  FIG. 6B , an example of an assembly method is illustrated. In a first operation  180 , a flex connector is aligned and placed on an MLB. Thereafter, in operation  182 , a socket is aligned on top of the flex connector onto the MLB, which may ensure that electrical connector pads of the flex are registered with pins of the socket for electrical communication therethrough, as well as ensuring registration of electrical connector pads or pins of the socket to those of the MLB. Thereafter in operation  184 , a package is placed in the socket, which may ensure that electrical connector pads of the package are registered with pins in the socket. Thereafter, in operation  186 , an upper compression member, which may be a heat sink, is positioned on top of the package and a compressive enabling force is applied down from and by the heat sink, which may establish electrical contact between the package, socket, flex connector, and MLB by compressing the stack of components together. A process as described with reference to  FIGS. 6A and 6B  may also be used to assemble any of the embodiments of  FIGS. 1-3C , with the lower flex connector&#39;s connector portion extending completely through a cutout portion of an overlying socket and directly connecting to a package. 
       FIGS. 7A and 7B  together illustrate and describe an embodiment of a process of assembling a stack of components. With reference first to  FIG. 7A  alone, the stack may include: an upper compression member, which may be a heat sink  102 ; package  104 , including a lower surface  160  including electrical connectors  163 ; socket  152 , which may include shelf or trench  161  on a bottom portion as described elsewhere herein, and which has an upper surface  172  and a lower surface  174 ; lower flex connector  114 , which may include a top surface  169  including electrical connectors  171 , and a bottom surface; and MLB  108 , which may include a top surface  162  having electrical connections  165  thereon. Package  104  may include a substrate  105  which may include a ledge area  204  adjacent to the compartment to receive and electrically connect to a flex connector  112 . Ledge area  204  may include a top surface  206  including electrical connectors  167 . 
     With reference to both  FIG. 7A  and  FIG. 7B , an example of an assembly method is illustrated. In a first operation  210 , a flex connector is aligned and placed on an MLB. Thereafter, in operation  212 , a socket is aligned on top of the flex connector onto the MLB, which may ensure that electrical connector pads of the flex connector are registered with pins of the socket for electrical communication therethrough, as well as ensuring registration of electrical connector pads or pins of the socket to those of the MLB. Thereafter, in operation  214 , a package is placed in the socket, which may ensure that electrical connector pads of the package are registered with pins in the socket. Thereafter, in operation  216 , an upper flex connector, which may include a connector portion  200  extending toward the package substrate  105 , may be aligned and placed onto the upper surface of the package substrate,  206 , in the ledge section  204  of the package substrate. The upper flex connector positioned in operation  216  may be held in place on the upper surface of the package substrate ledge,  206 , by a low strength mechanism, which may include magnets, low strength adhesive, or the like, between the flex connector and the upper surface of the package substrate ledge  206 . The combined height of the upper flex connector  112 , including the connector portion  200 , and of the package substrate  105  in ledge section  204  may be the same as the overall height of the package  104 . Thereafter, in operation  218 , an upper compression member, which may be a heat sink, is positioned on top of the package and the upper flex connector, and a compressive enabling force is applied down from and by the heat sink, which may establish electrical contact between the package, socket, flex connector, and MLB by compressing the stack of components together. A process as described with reference to  FIGS. 7A and 7B  may be used to assemble any of the embodiments of  FIGS. 1-3C , with the lower flex connector&#39;s connector portion extending completely through an overlying socket and directly connecting to a package. 
     Dashed lines  168 ,  170  may indicate that flex connector  112  and/or  114 , and MLB  108 , may extend well beyond the portions illustrated in the drawing figure. Lines  168 ,  170  may also indicate that a second stack, which may be the same as or different from the stack illustrated in  FIGS. 6A and 7A , is adjacent thereto and may be assembled at the same time, implementing operations which may be the same as those illustrated in and described with reference to  FIGS. 6A and 6B , and  FIGS. 7A and 7B . Thus, lines  168  and  170  may indicate that a process as described with reference to  FIGS. 6A and 6B , or with reference to  FIGS. 7A and 7B , may include forming two or more stacks simultaneously, with opposite ends of flex connector  112  and/or  114  interconnecting at least two of the stacks, and the stacks may be formed on the same MLB and electrically interconnected therethrough. 
       FIG. 8  illustrates a top plan view of a point of a process of interconnecting multiple stacks via flex connector  112  and/or flex connector  114 . As discussed above,  FIG. 8  illustrates that multiple stacks of components may be assembled on the same MLB  108 , which assembly may be simultaneous, with flex connector  112  and/or flex connector  114  electrically connecting two or more of the stacks. Flex connector  112  and/or flex connector  114  may be an assembly of a flexible printed circuit (FPC) and a connector at the end of the FPC, which may be pre-assembled together. Thus, when flex connector  112  and/or flex connector  114  is connected between two or more stacks, e.g., two or four stacks as illustrated in  FIG. 8 , the term flex connector includes, but is not limited to, an FPC, optionally of a custom length, with connectors on either end of the FPC.  FIG. 8  also illustrates that a package  104  may be configured to include multiple ledge portions (two being illustrated for each, but more than two may also be provided) located at different lateral sides of the package, and thus numerous combinations of upper flex connector(s) and lower flex connector(s) may be made for any one package. 
       FIG. 9A  illustrates an embodiment of a heat sink  300 . Heat sink  300  may include a body  302  formed of one or more materials which act to transfer heat through the body, e.g., between upper and lower surfaces, e.g., copper. Body  302  may include one or more through holes  350  extending through the body from top to bottom, which may be located at any location in the body. Hole or holes  350  may align with the other alignment features described herein, e.g., fasteners  111 , so that the heat sink  300  can be forced into contact with other components described elsewhere herein. In an embodiment, heat sink  300  is used and assembled with components in a manner similar to heat sink  102 , and may hold one or more other components between the heat sink and an MLB, such as MLB  108 . 
     Heat sink  300  may include one or more load controlling inserts  304  which may be positioned within corresponding cavities  306  formed in the body  302 , and are formed of a material which can transmit forces as described herein, e.g., aluminum. Inserts  304  may be positioned so that, when body  302  is positioned over a stack of components, for example a stack such as that illustrated in  FIG. 7A , with the inserts on the bottom of the body, the one or more inserts align over part or all of a flex connector, such as connector  112 , and may more specifically be positioned over a top side of a connector portion  126  of a flex connector. As described in greater detail elsewhere herein, a load controlling insert  304  may apply an adjustable force to one or more components in the stack, e.g., a connector portion of a flex connector, which may assist in creating and maintaining electrical contact between the connector portion and an adjacent component in the stack. 
       FIG. 9B  illustrates a cross-sectional view taken at line C-C in  FIG. 7A , and illustrates body  302  including a cavity  306  in which an exemplary load controlling insert  304  is mounted. Insert  304  may include one or more force control assemblies  308 . Each force control assembly, of which three are illustrated only by way of a non-limiting example, is configured to transmit a variable force from the body  302  to a component underlying the assembly  308 . The drawing figures show a linear arrangement of force control assemblies  308 ; however, other arrangements are also possible. Other embodiments can be arranged in a rectangle, triangle, circle, or any other geometric shape or pattern, to distribute compressive forces from the body  302  to an underlying component in the stack. 
     Each assembly  308  can be identical to other such assemblies  308  in a single body  302 , or they can be different in size and/or force transmission. Assemblies  308  are illustrated as being generally rectangular, but may also be any other shape, e.g., circular or polygonal. 
       FIG. 9C  illustrates a cross-sectional view similar to  FIG. 3B , with heat sink  300  positioned at the top of a stack of components, which may be any of the components described elsewhere herein. Body  302  is held to MLB  108  using fasteners (not illustrated), which may be fasteners  111 , with the other components between as described elsewhere herein. A connector portion  126  of a flex connector may be positioned directly adjacent and underneath load controlling insert  304 , with the insert  304  exerting a load on the connector portion which may be dependent on one or more predetermined settings of the force control assemblies  308 . 
       FIG. 10  illustrates a greatly enlarged cross-sectional view of a portion of load controlling insert  304 , including a single force control assembly  308 . A through bore  320  may be formed in body  302 , which may be internally threaded. Assembly  308  may include a fastener  322  which connects and secures the assembly  308  to the body  302 . Fastener  322  may be a screw, a rivet, a press-fit shaft, or any other fastener which can secure assembly  308  to body  302 . In an embodiment illustrated in  FIG. 10 , fastener  322  is a screw, and includes external threads which mate with internal threads of bore  320 , when provided. Fastener  322  may be circular in cross-section, e.g., when the fastener is a screw, but may also have any other cross-sectional shape. 
     Fastener  322  may include a first section  324  which fits into bore  320  and is secured therein. Fastener  322  may include a second section  326 , which may be contiguous with first section  324 , and may have an outer dimension, which may be an outer diameter, larger than an outer dimension or diameter of first section  324 . When the outer dimension of the second section  326  is larger than the outer dimension of the first section  324 , a shoulder  346  is formed between the two sections. Fastener  322  may also include a third section  328 , which may be contiguous with second section  326 , and may have an outer dimension, which may be an outer diameter, larger than an outer dimension or diameter of second section  326 . When the outer dimension of the third section  328  is larger than the outer dimension of the second section  326 , a shoulder  338  is formed between the two sections. Fastener  322  may optionally include a torque transmission element opening at the end of the fastener opposite first section  324 , so that when the fastener must be rotated about its longitudinal axis, e.g., when it is a screw, a mating driver can transmit torque to the fastener. 
     Assembly  308  may include a variable force transmission member  330  interposed between the body  302  and the insert  304 . In an illustrated embodiment of  FIG. 10 , member  330  may be a coil spring, but member  330  is not so limited and may be any of a disc spring or stack thereof, wave spring or stack thereof, polymer sleeve spring, or any other such device which functions to transmit a variable amount of force. The member  330  is captured between the body  302  and the insert  304  in a cavity  334  formed between an outer retaining wall  332 , which may be cylindrical, and an inner post  336 . Inner post  336  may be hollow and receive within it at least portions of fastener  322 . Inner post  336  may include an inner shoulder  340  defined within cavity  342 , the inner shoulder  340  defined at a point along the cavity at which the inner dimension, which may be a diameter, changes from a first, smaller dimension to a second, larger dimension. Inner shoulder  340  may act as a limit or stop against motion of the fastener  322 , e.g., by engaging against shoulder  338 . Cavity  342  includes an opening  344 . 
     In operation, variable force transmission member  330  is positioned at least partially in cavity  334 . Fastener  322  is then inserted through opening  344  into and through cavity  342 , until first section  324  is at least partially in bore  320 . Shoulder  338  and inner shoulder  340  engage each other, holding the insert  304  in place. If fastener  322  is a screw, the fastener is turned so that it threads into the internal threads of bore  320  a predetermined amount, which may be less than an amount when shoulder  346  engages body  302 . In this manner, the amount of force transmitted by member  330  can be tailored to specific needs of the components of the stack, e.g., so that a connector portion of a flex connector, as illustrated in  FIG. 9C , is not damaged but is still held in place and maintains its electrical connections. If the fastener  322  is a rivet or press-fit fastener, it is secured in a known manner to the body  302  without necessarily rotating the fastener in bore  320 ; however, the longitudinal length of the rivet or press-fit fastener also may determine an amount by which the member  330  is pre-loaded, if at all. In embodiments, the insert  304  floats relative to the body  302 , because of the dual actions of the fastener  322  and the variable force generating member  330 . 
     In utilizing the various aspects of the embodiments, it would become apparent to one skilled in the art that combinations or variations of the above embodiments are possible for integrating sockets and flex connectors. Although the embodiments have been described in language specific to structural features and/or methodological acts, it is to be understood that the appended claims are not necessarily limited to the specific features or acts described. The specific features and acts disclosed are instead to be understood as embodiments of the claims useful for illustration. The entirety of each of the aforementioned documents is incorporated by reference herein.

Metadata:
Filing Date: 20200925
Publication Date: 20220726
Grant Date: 20220726
Priority Date: 20200925
Inventors: HARDIKAR, MAHESH S.
SECKER, DAVID A.
SWAMINATHAN, RAJASEKARAN
KOLLIPARA, RAVINDRANATH T.
ATKINSON, ROBERT R.
Assignee: APPLE INC
CPC Classifications: [{"code": "H05K2201/10962", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01R13/24", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K2203/167", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K2201/0311", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01R12/716", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K2201/10378", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K3/325", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01R12/716", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01R13/24", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 80821672