Review of Electrically Conductive Adhesive Technologies for Electronic Packaging

Abstract

Conductive adhesives (ICAs; Isotropic Conductive Adhesive, ACAs; An-isotropic Conductive Adhesive NCAs; Non-conductive Adhesive) offers promising Pb-free process and material solutions for electronic packaging technology to be fine pitch interconnects, low cost and low temperature process and environmentally clean approaches. ICA has been developed and used widely for traditionally solder replacement, especially in surface mount devices and flip chip application. It also need to be lower cost and higher electrical/mechanical and reliability performances. ACAs have been widely used in flat panel display modules to be high resolution, light weight, thin profile and low power consumption in the film forms (Anisotropic Conductive Films; ACFs) for last decades. Multi-layered ACF structures such as double and triple-layered ACFs were developed to meet fine pitch interconnection, low temperature curing and strong adhesion requirements. High mechanical reliability, good electrical performance at high frequency level and effective thermal conductivity for high current density are some of required properties for ACF materials to be pursued for wide usage in flip chip technology. Recently, NCAs are becoming promising for ultra-fine pitch interconnection and low cost joining materials in electronic packaging applications. In this paper, an overview on the recent development and applications of conductive adhesives for electronic packaging with focus on fine pitch capability, electrical/mechanical/thermal performance and wafer level package application are described.