Influence of multi-walled carbon nanotube (MWCNT) concentration on the thermo-mechanical reliability properties of solderable anisotropic conductive adhesives (SACAs)

Abstract

In the present work, the influence of multi-walled carbon nanotube (MWCNT) concentration on the thermo-mechanical reliability properties of carbon nanotube (CNT)-filled solderable anisotropic conductive adhesives (SACAs) containing low-melting-point-alloy (LMPA) fillers was investigated. To measure the reliability-related properties of SACA assemblies, six types of SACAs with different MWCNT concentrations (from 0 to 2 wt%) were formulated, and two types of reliability tests, thermal shock (TS) and high-temperature and high-humidity (HTHH) tests, were conducted on these samples. All of the CNT-filled SACA assemblies with different MWCNT concentrations showed proper and stable electrical reliability during each aging test, due to the molten LMPA fillers forming a metallurgical interconnection between the corresponding metallization regions. Although the mechanical strength of the CNT-filled SACA joints degraded after aging tests due to excessive intermetallic compound (IMC) layer growth, the CNT-filled SACAs with an MWCNT concentration below 0.1 wt% exhibited better mechanical reliability properties than those of SACAs without MWCNTs due to the initially achieved high bonding strength of the SACA joints, enabled by the reinforcing effects of the MWCNTs within the polymer composites.