Review of Recent Advances in Electrically Conductive Adhesive Materials and Technologies in Electronic Packaging

Abstract

Electrically Conductive Adhesives (ICAs: Isotropic Conductive Adhesives; ACAs: An-isotropic Conductive Adhesives; and NCAs: Non-conductive Adhesives) offer promising material solutions for fine pitch interconnects, low cost, low-temperature process and environmentally clean approaches in the electronic packaging technology. ICAs have been developed and used widely for traditional solder replacement, especially in surface mount devices and flip chip application. These also need to be lower cost with higher electrical/mechanical and reliability performances. ACAs have been widely used in flat panel display modules for high resolution, lightweight, thin profile and low power consumption in 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. Also, ACAs have been attracting much attention for their simple and lead-free processing as well as cost-effective packaging method for semiconductor packaging applications. 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 a 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 of the recent developments and applications of electrically conductive adhesives for electronic packaging with focus on fine pitch capability, electrical/mechanical/thermal performance and wafer level packaging application is presented.