ABSTRACT
Electronic packages nowadays are becoming smaller, lighter with higher in/out (I/O) count and better performance and must be cost competitive. The trend in electronic packaging runs from bulky plastic ball grid arrays (PBGAs) with solder joints to miniature flip-chips with anisotropic conductive adhesive interconnects. Meanwhile, the environmentally-friendly manufacturing is another important goal for the electronic packaging industry. In particular, the use of anisotropic conductive adhesives (ACAs) instead of soldering and underfill encapsulation helps to achieve such goals. The interest in using an ACA, instead of solder, comes partly from the fact
that the use of an ACA for the direct interconnection of flipped silicon chips to printed circuits (flip-chip packaging), offers numerous advantages such as reduced thickness, improved environmental compatibility, lower assembly process temperature, increased metallization options, reduced cost, and decreased equipment needs [1-9]. There are also several review papers on the topic of ACAs [10, 11]. The application of ACA joints in such cases as smart cards, disk drives, and driver chips for electronic assemblies has attracted much interest and has been widespread, including on glass substrates [12-16], flexible circuits [17-20], rigid board [21, 22], and ceramic substrate [23, 24].
