Multi-Chip Module (MCM) of a Computer System

Abstract

A MCM system board uses a stiffener arrangement to enhance mechanical, thermo and electrical properties by incorporating an LGA compression connector in a computer system. The present designs of large scale computing systems (LSCS) in IBM use a MCM that is attached to a system board and held together by a stiffening frame. Due to the nature of the manufacturing of the system board, there can be significant gaps formed in the mounting area of the MCM between the board and the stiffener. A method is described that not only fills the void, it also, in addition promotes thermo conduction of excess heat away from the MCM and at the same time promotes enhanced electrical properties of the LGA connections of the MCM to the system board.

1 . A multi-chip module (MCM) of a computer system, comprising: 
 a thermo-conducting gel package positioned and compressed between a mechanical stiffener and a printed circuit board (PCB) system board, wherein said thermo-conducting gel package is formed as a self-conforming insulator structure shaped like a cushion of two separate insulating layers filled with a non-compressible thermo-conducting gel paste insulating material and causing said gel package to conform to all irregularities and to apply equal contact pressure to a printed board surface after assembly of said thermo-conducting gel package after positioning and compression of said thermo-conducting gel package between said mechanical stiffener and said printed circuit board promoting better thermo properties of said MCM in said the computer system.    
   
   
       2 . The multi-chip module (MCM) of a computer system according to  claim 1  wherein said thermo-conducting gel package compressed between said mechanical stiffener and said PCB printed circuit board comprising a non-compressible insulating thermo paste.  
   
   
       3 . The multi-chip module (MCM) of a computer system according to  claim 1  wherein said thermo-conducting gel package is in direct contact with heat carrying electrical plated through holes (PTH) of said PCB system board.  
   
   
       4 . The multi-chip module (MCM) of a computer system according to  claim 1  where a land grid array (LGA) of said MCM generates heat which is transported is transported to the mechanical stiffener acting as a solid mass heat sink through the thermo conducting gel package.  
   
   
       5 . The multi-chip module (MCM) of a computer system according to  claim 1  wherein heat removal from said MCM reduces the thermo-flexing of the PCB system board.  
   
   
       6 . The multi-chip module (MCM) of a computer system according to  claim 3  wherein heat removal from said MCM reduces the thermo-flexing of the PCB system board and enables said PCB system board to support increased system operational speeds.  
   
   
       7 . The multi-chip module (MCM) of a computer system according to  claim 3  wherein said thermo-conductive gel package pressure on said PCB system board provides uniform counter pressure on the PCB system board in the MCM's contact area with the mechanical stiffener.  
   
   
       8 . The multi-chip module (MCM) of a computer system according to  claim 7  wherein said thermo-conductive gel package forms a void filling structure between the PCB system board and the supporting heat sink mechanical stiffener.  
   
   
       9 . The multi-chip module (MCM) of a computer system according to  claim 1  wherein said thermo-conductive gel package reduces heat fluxing of the PCG system board by the structural support provided by the gel package.  
   
   
       10 . The multi-chip module (MCM) of a computer system according to  claim 1  wherein said thermo-conductive gel package is compressed in said MCM to provide constant counter pressure in an land grid array (LGA) connection area of said MCM to lower the contact resistance of MCM-LGA electrical interface connections.