Influence of Carbon Nanotube Concentration on the Interconnection Properties of Solderable Isotropic and Anisotropic Conductive Adhesive

Abstract

In this paper, two types of multi-walled carbon nanotube (MWCNT)-filled solderable electrically conductive adhesive (SECA) systems were formulated, a solderable isotropic conductive adhesive (SICA) containing 40 vol% of low melting point alloy (LMPA), and a solderable anisotropic conductive adhesive (SACA) with 20 vol% of LMPA, with different MWCNT contents (0, 0.03, 0.5 and 2 wt%). A quad flat package (QFP) interconnection test was conducted for each SECA system to investigate the influence of the MWCNT concentration on the interconnection properties of the SICA and SACA systems. The results indicated that the interconnection properties (i.e., electrical and mechanical properties) of each SECA were enhanced at low MWCNT concentration, due to the reinforcing effects of the MWCNT. However, the interconnection properties of each SECA joint deteriorated with increasing MWCNT concentration over 0.5 wt% because of defects in the conduction path, such as entrapped MWCNT-filled polymer (SICA), or reduction of the conduction path area (SACA) due to increased polymer viscosity and diminished molten LMPA mobility. Key words: Anisotropic conductive adhesive, Defect, Interconnection properties, Isotropic conductive adhesive, Low melting point alloy, Multi-walled carbon nanotube