Flexible land grid array connector

Abstract

An LGA connector is used to interconnect an LGA package and a printed circuit board. The LGA connector includes an elastomeric body with a plurality of through-holes. Metal films are formed on inner walls of through-holes and splay out around the mouths of their upper and lower openings. The metal films are formed by vacuum metallization, sputtering, chemical plating, electrical plating or PVD. The through-holes have a funnel-like shape to absorb external stresses and redirect the stress to shrink the through-hole diameters. Moreover, the metal films' elastic deformation is larger than conventional metal conductive fillers so as to improve reliability.

Description

BACKGROUND [0001] 1. Field of Invention [0002] The present invention relates to a flexible land grid array connector. More particularly, the present invention relates to a flexible connector between a land grid array connector and a printed circuit board. [0003] 2. Description of Related Art [0004] Integrated circuits are typically housed within a package, which is designed to protect the circuit from damage, provide adequate heat dissipation during operation, and provide electrical connection between the integrated circuits and the leads of a printed circuit board. Several conventional package types, such as land grid array (LGA), pin grid array (PGA), ball grid array (BGA) and column grid array (CGA), are designed to provide the above functions. [0005] The current trend for connector design in the computer field is to provide both high-density and high-reliability connections between various major circuit devices of a computer. High reliability for such connections is essential du...

AI Technical Summary

Benefits of technology

[0009] It is therefore an objective of the present invention to provide a flexible LGA connector, so as to provide reliable electrical connection and enhance its durability.

[0010] In accordance with the foregoing and other objectives of the present invention, an LGA connector is used to interconnect an LGA package and a printed circuit board. The LGA connector includes an elastomeric body with a plurality of through-holes. Metal films are formed on inner walls of the through-holes and splay out around the mouths of their upper and lower openings. The metal films are formed by vacuum metallization, sputtering, chemical plating, electrical plating or PVD (physical vapor deposition). The through-holes have a funnel-like shape to absorb external stresses by redirecting the stress to shrink the diameters of the through-holes. Moreover, the metal films' elastic deformation is larger than conventional metal conductive fillers so as to improve reliability.

[0011] According to another preferred embodiment, a triple-layered elastomeric body is provided when corresponding contact electrodes of an LGA package and a printed circuit board are mismatched in position. An upper elastomeric layer and a lower elastomeric layer made of rubber exist, which have a plurality of funnel-like through-holes formed by etching. A metal layer is formed on an inner wall and around each upper and lower opening of each through-hole of each layer. An interconnection elastomeric layer made of rubber exists, which has a plurality of funnel-like through-holes formed by etching. A metal layer is formed on an inner wall and around each upper and lower opening of each through-hole so as to interconnect the metal layer of the upper and lower elastomeric layer. Thus, the LGA connector in this preferred embodiment can interconnect an LGA package and a printed circuit board even when corresponding contact electrodes are mismatched in position.

Problems solved by technology

As both module size and distance from which solder connections are located to the center of the module (i.e., the distance from neutral point, hereafter DNP) continue to increase, even CGA solder connections can become unreliable, especially due to thermal fatigue.

These same concerns about broken interconnections also apply to PGA applications when the DNP is too large.

As the number of lands is increased, the pitch between contacts decreases and manufacturing problems consequently increase.

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