Thin module system and method

Abstract

A flexible circuit has contacts for mounting in a socket or card edge connector. The flexible circuit includes integrated circuit devices mounted on both sides of the edge connector contacts. Preferably, the flexible circuit is wrapped about an edge of a rigid substrate and presents contacts on both sides of the substrate for mounting in a socket. Multiple flexible circuits may be overlaid with the same strategy. The flexible circuit may exhibit one or two or more conductive layers, and may have changes in the layered structure or have split layers.

1 . A memory expansion board comprising: 
 (a) a rigid substrate having two opposing lateral sides and an edge;    (b) a flex circuit wrapped about the edge of the rigid substrate, the flex circuit having a first side and a second side, a portion of the flex circuit attached to at least one of the lateral sides of the rigid substrate, the flex circuit having plural contacts adapted for connection to a circuit board socket, the plural contacts being disposed near the edge of the rigid substrate on the outside side of the flex circuit;    (c) plural memory CSPs mounted on the first side and second side of the flex circuit.    
   
   
       2 . The memory expansion board of  claim 1  in which the plural CSPs each have a top surface and one or more of the top surfaces of the plural CSPs is attached to the rigid substrate.  
   
   
       3 . The memory expansion board of  claim 1  in which the rigid substrate is made of a conductive material.  
   
   
       4 . The memory expansion board of  claim 1  in which the rigid substrate is made of a thermally conductive material.  
   
   
       5 . The memory expansion board of  claim 1  in which the rigid substrate has an extension.  
   
   
       6 . The memory expansion board of  claim 1  further comprising at least one alignment opening of the flex circuit matching at least one alignment opening of the rigid substrate.  
   
   
       7 . The memory expansion board of  claim 1  further comprising at least one alignment opening of the flex circuit matching at least one alignment protrusion of the rigid substrate.  
   
   
       8 . The memory expansion board of  claim 1  further comprising at least one alignment tab of the rigid substrate.  
   
   
       9 . A circuit module comprising: 
 a substrate having a first and a second lateral side and a first perimeter edge and a second perimeter edge;    a flex circuit having a first side and a second side, the first side having expansion board contacts adapted for connection to an expansion board slot and having a set of contact arrays, the flex circuit being wrapped about the first perimeter edge of the substrate to place the expansion board contacts of the first side closer to the first perimeter edge of the substrate than is disposed the set of contact arrays and to place the second side of the flex circuit closer to the lateral sides of the substrate than is disposed the first side of the flex circuit.    
   
   
       10 . A circuit module comprising: 
 a substrate having a first and a second lateral side and a first perimeter edge and a second perimeter edge;    a flex circuit having a first side and a second side, the first side having expansion board contacts adapted for connection to an expansion board slot and having a set of contact arrays, the flex circuit being wrapped about the first perimeter edge of the substrate to place the expansion board contacts of the first side closer to the second perimeter edge of the substrate than is disposed the set of contact arrays and to place the second side of the flex circuit closer to the lateral sides of the substrate than is disposed the first side of the flex circuit.    
   
   
       11 . A circuit module comprising a flex circuit having a first side having contacts adapted for connection to a socket, a second side, and being imposed with a bend to form an open-ended pocket having an inward side and an outward side and being open at one end and closed at the other end of the pocket, the first side of the flex circuit being on the outward side of the pocket and the second side of the flex circuit being on the inward side of the pocket.  
   
   
       12 . The circuit module of  claim 11  further comprising a rigid interposer disposed at least partially in the open-ended pocket of the flex circuit.  
   
   
       13 . The circuit module of  claim 12  in which the rigid interposer is made of a conductive material.  
   
   
       14 . The circuit module of  claim 11  further comprising a support member disposed at least partially in the open-ended pocket of the flex circuit.  
   
   
       15 . The circuit module of  claim 11  further comprising a heat-conducting member disposed at least partially in the open-ended pocket of the flex circuit.  
   
   
       16 . The circuit module of  claim 12 , in which the rigid interposer has a necked narrow portion disposed adjacent to the closed end of the pocket.  
   
   
       17 . The circuit module  11  in which the flex circuit has two end portions, each end portion having a plurality of memory CSPs mounted on the first and second sides of the flex circuit.  
   
   
       18 . A circuit module comprising: 
 (a) a flex circuit having an inner side and an outer side;    (b) plural CSPs mounted along the inner side and the outer side of the flex circuit;    (c) a bend in the flex circuit between first and second portions of the flex circuit, the first and second portions each having contacts arranged along their outer side, the contacts for mounting the circuit module in a card edge connector, the bend separating a first set of the plural CSPs from a second set of the plural CSPs;    (d) a support structure about which the flex circuit transits through the bend.    
   
   
       19 . The circuit module of  claim 18  in which at least one of the CSPs on the inner side of the flex circuit is adhesively connected to the support structure.  
   
   
       20 . The circuit module of  claim 18  in which at least one of the CSPs on the inner side of the flex circuit is thermally connected to the support structure.  
   
   
       21 . The circuit module of  claim 18  in which a portion of the flex circuit is laminated to the support structure.  
   
   
       22 . The circuit module of  claim 18  in which the bend in the flex circuit creates an open-ended pocket having a closed end and an open end and the support structure exhibits a first portion having a first thickness at the closed end of the pocket and presents a second portion having a second thickness at the open end of the pocket in the flex circuit.  
   
   
       23 . The circuit module of  claim 18  in which the support structure has a first portion and a second portion, the first portion being thinner than the second portion.  
   
   
       24 . A method for devising a circuit module comprising the steps of: 
 providing a flex circuit having first and second sides and first and second long perimeter edges and first and second short perimeter edges with a set of module contacts along the first side and first and second pluralities of CSPs disposed laterally about the set of module contacts to place the first plurality of CSPs nearer the first long perimeter edge of the flex circuit than is disposed the set of module contacts and the second plurality of CSPs nearer the second long perimeter edge of the flex circuit than is disposed the set of module contacts;    a substrate having first and second lateral sides and a first long perimeter edge and a second long perimeter edge;    wrapping the flex circuit about the substrate to dispose the second side of the flex circuit closer to the first and second lateral sides of the substrate than is disposed the first side of the flex circuit and to dispose the set of module contacts nearer the first long perimeter edge of the substrate than the second long perimeter edge of the substrate and to place the first plurality of CSPs closer to the first lateral side of the substrate than is disposed the second plurality of CSPs.    
   
   
       25 . The method of  claim 24  in which the provided flex circuit has third and fourth pluralities of CSPs.  
   
   
       26 . The method of  claim 24  in which the CSPs are each stacked modules composed of two or more individual CSPs.  
   
   
       27 . A method for providing increased memory capacity for a computer system comprising the steps of: 
 providing a circuit module in accordance with  claim 1  and inserting said module into an expansion slot.    
   
   
       28 . A method for providing increased memory capacity for a computing system comprising the steps of: 
 providing a circuit module devised in accordance with  claim 24  and inserting said module into an expansion slot on a motherboard.    
   
   
       28 . A method of assembling a circuit module comprising the steps: 
 providing a flex circuit having a first side and a second side, the first side having a plurality of pads for mounting components and a plurality of contacts for insertion in an expansion board slot; the second side having a plurality of pads for mounting components;    mounting plural CSPs along the first side of the flex circuit;    mounting plural discrete components along the first side of the flex circuit;    mounting plural CSPs along the second side of the flex circuit;    mounting plural discrete components along the second side of the flex circuit;    providing a rigid substrate having first and second major surfaces and an edge; and    wrapping the flex circuit about the edge of the rigid substrate, with the first side facing outward, such that a first set of the plurality of contacts are disposed proximal to the edge of the rigid substrate.    
   
   
       29 . The method of  claim 28  in which the step of wrapping the flex circuit further includes wrapping such that a second set of the plurality of contacts are disposed proximal to the edge of the rigid substrate.  
   
   
       30 . The method of  claim 28  further including the step of attaching at least one of the plural CSPs along the second side of the flex circuit to the rigid substrate.  
   
   
       31 . The method of  claim 28  further including the step of thermally connecting at least one of the plural CSPs along the second side of the flex circuit to the rigid substrate.  
   
   
       32 . The method of  claim 28  further including the step of attaching a heat radiating clip to selected ones of the plural CSPs.  
   
   
       33 . The method of  claim 28  further including the step of attaching a heat radiating element to at least one of the CSPs along the first side of the flex circuit.  
   
   
       34 . The method of  claim 28  further including the step of inserting the plurality of contacts at least partially into an expansion board slot for connection to an operating environment.  
   
   
       35 . A method of assembling a circuit module comprising the steps: 
 providing a flex circuit having a first side and a second side and a plurality of contacts along the first side for insertion in an expansion board slot;    mounting at least first and second CSPs along the first side of the flex circuit;    providing a rigid substrate having first and second major sides and an edge;    wrapping the flex circuit about the rigid substrate to dispose the first of the at least first and second CSPs closer to the first major side of the rigid substrate than the second major side of the substrate and dispose the second of the at least first and second CSPs closer to the second major side of the rigid substrate than the first major side of the substrate and attaching the flex circuit to the rigid substrate such that the plural contacts are presented proximal to the edge of the rigid substrate for insertion into the expansion board slot.    
   
   
       36 . The method of  claim 35  in which the step of attaching the flex circuit to the rigid substrate comprises lamination.  
   
   
       37 . The method of  claim 35  further comprising mounting third and fourth CSPs along the second side of the flex circuit.  
   
   
       38 . The method of  claim 35  in which the rigid substrate is made of heat conducting material.  
   
   
       39 . The method of  claim 35  in which the rigid substrate has first portion and a second portion, the first portion being thinner than the second portion.  
   
   
       40 . The method of  claim 35  further including the step of thinning the rigid substrate along the edge of the rigid substrate.  
   
   
       41 . The method of  claim 35  further including the step of aligning a tooling hole of the flex circuit with a tooling hole of the rigid substrate.  
   
   
       42 . A populated flexible circuit comprising: 
 a flexible circuit having a first major side and a second major side, the flexible circuit exhibiting along the first major side, first-side first and second sets of contact site arrays between which is located a row of connector contacts, the second major side of the flexible circuit exhibiting second-side first and second sets of contact site arrays which correspond to the first-side first and second sets of contact site arrays, each of the first-side and second-side first and second sets of contact site arrays comprising at least two surface mount arrays, the flexible circuit providing connections between the at least two surface mount arrays of each of the first-side first and second sets of contact site arrays and the at least two surface mount arrays of each of the second-side first and second sets of contact site arrays;    a plurality of CSPs that populate the at least two surface mount arrays of each of the first-side first and second sets of contact site arrays and the at least two surface mount arrays of each of the second-side first and second sets of contact site arrays.    
   
   
       43 . A circuit assembly comprising: 
 a flexible circuit having a first major side and a second major side, the flexible circuit having at least one or more rows of surface mount arrays on the first major side and two or more rows of surface mount arrays on the second major side, the flexible circuit having a arcuate bend between a selected two of the two or more rows of surface mount arrays on the second major side, the second major side facing inward to the arcuate bend, the flexible circuit having an end edge and connector contacts disposed proximal to the end edge;    a plurality of CSPs that populate the one or more rows of surface mount arrays of the first major side and the two or more rows of surface mount arrays of the second major side, each of the CSPs having a top major surface;    a support substrate partially within the arcuate bend, the support substrate having a first side and a second side and an edge, at least one of the top major surfaces of the plurality of CSPs populating the two or more rows of surface mount arrays of the second major side being attached to the support substrate, the edge of the support substrate being adapted for insertion into a card edge connector.    
   
   
       44 . A circuit assembly comprising: 
 a flexible circuit having a first major side and a second major side, the flex circuit having two or more rows of surface mount arrays on the second major side, the flexible circuit having an arcuate bend between a selected two of the two or more rows of surface mount arrays on the second major side, the second major side facing inward to the arcuate bend, the flexible circuit having an end edge and connector contacts disposed proximal to the end edge;    a plurality of CSPs that populate the two or more rows of surface mount arrays of the second major side, each of the CSPs having a top major surface;    a support substrate partially within the arcuate bend, the support substrate having a first side and a second side and an edge, at least one of the top major surfaces of the plurality of CSPs populating the two or more rows of surface mount arrays of the second major side being attached to the support substrate, the edge of the support substrate being adapted for insertion into a card edge connector.    
   
   
       45 . A circuit module comprising: 
 a rigid substrate having two opposing lateral sides and two opposing end edges;    a flexible circuit wrapped about at least one of the two opposing end edges, the flexible circuit having a first side and a second side each having one or more rows of contact site arrays, a portion of the flex circuit being attached to at least one of the lateral sides of the circuit board, the flex circuit having plural contacts adapted for electrical connection to a card edge connector.    
   
   
       46 . The circuit module of  claim 45  in which the plural contacts are on the first side of the flex circuit, and in which a portion of the second side of the flex circuit opposite at least some of the plural contacts is laminated to the rigid substrate.  
   
   
       47 . A circuit module comprising: 
 a circuit board having two opposing lateral sides and an edge;    a flex circuit wrapped around the edge of the rigid substrate, the flex circuit having an inner side and an outer side, the inner and outer sides each having two or more rows of contact site arrays, a portion of the flex circuit being laminated to at least one of the lateral sides of the circuit board, the flex circuit having plural contacts adapted for electrical connection to the circuit board;    a plurality of CSPs mounted to the two or more rows of contacts site arrays of the inner side and the outer side of the flex circuit.    
   
   
       48 . A method to encourage the extraction of thermal energy from a CSP that operates in conjunction with at least one other CSP comprising the steps of: 
 providing a first CSP having a top surface and a bottom surface, there being CSP contacts along the bottom surface;    providing a thermally conductive substrate member and attaching the first CSP to the thermally conductive substrate member;    providing a flex circuit and attaching the first CSP to the flex circuit, the attachment being effectuated employing the CSP contacts of the first CSP and employing the thermally conductive substrate member as a support for a part of the flex circuit;    providing a second CSP having a bottom surface and CSP contacts and attaching the second CSP to the flex circuit, the attachment being effectuated employing the CSP contacts of the second CSP so that the CSP contacts of the first CSP are separated from the CSP contacts of the second CSP by a part of the flex circuit.    
   
   
       49 . The method of  claim 48  further comprising a set of contacts electrically connected to the flex circuit to provide connective facility for the first and second CSPs to an operating environment.  
   
   
       50 . The method of  claim 48  in which the thermally conductive substrate member is comprised of a metal.  
   
   
       51 . The method of  claim 50  in which the thermally conductive substrate member is comprised of aluminum.  
   
   
       52 . The method of  claim 50  in which the thermally conductive substrate member is comprised of a radiative portion having fins.  
   
   
       53 . The method of  claim 48  in which the thermally conductive substrate member is comprised of FR4 and a metallic layer.  
   
   
       54 . The method of  claim 48  in which the attachment of the first CSP to the thermally conductive substrate member is by the top surface of the first CSP.  
   
   
       55 . A circuit module to encourage the extraction of thermal energy from a CSP that operates in conjunction with at least one other CSP comprising: 
 a first CSP having a top surface and a bottom surface and CSP contacts, the CSP contacts being along the bottom surface;    a thermally conductive substrate member attached to the first CSP;    a flex circuit attached to the first CSP, the attachment being effectuated employing the CSP contacts of the first CSP, the thermally conductive substrate member being a support for a part of the flex circuit;    a second CSP attached the flex circuit, the attachment being effectuated employing the CSP contacts of the second CSP so that the CSP contacts of the first CSP are separated from the CSP contacts of the second CSP by at least a part of the flex circuit.    
   
   
       56 . A circuit module comprising: 
 a substrate having first and second lateral sides and a cavity;    flex circuitry having a first portion adjacent to the first lateral side of the substrate and a second portion adjacent to the second lateral side of the substrate;    the flex circuitry having edge card connector contacts;    a connector having first and second parts which are selectively joinable;    the first part of the connector being connected to the first portion of the flex circuitry and the second part of the connector being connected to the second portion of the flex circuitry, the first and second parts of the flex circuitry being joined in the cavity of the substrate.