Effect of dispersion condition of multi-walled carbon nanotube (MWNT) on bonding properties of solderable isotropic conductive adhesives (ICAs)

Abstract

Carbon nanotubes have been considered as reinforcements in composite materials because of their exceptional mechanical, electrical, and thermal properties. In this paper, the effect of dispersion conditions of multi-walled carbon nanotubes (MWNTs) on bonding properties of solderable isotropic conductive adhesives (ICA) was investigated. Two types of ICAs, untreated pristine MWNT-filled ICAs and acid-treated MWNT (a-MWNT)-filled ICAs were formulated with 1 wt% MWNTs and 83 wt% low-melting-point alloy (LMPA) fillers. X-ray photoelectron spectroscopy analysis was conducted to characterize the surface chemical states of pristine and a-MWNTs and verify the effectiveness of a-MWNTs. The fracture surface of the polymer matrix and solderable ICAs with a-MWNTs showed good dispersion conditions through field-emission scanning electron microscope. After the interconnection process, the a-MWNT-filled solderable ICA showed uniform dispersion of MWNTs in the polymer matrix and formed a stable metallurgical conduction path because of the good rheology-coalescence-wetting behavior of LMPA. Alternatively, pristine MWNT-filled ICA showed poor dispersion and an unstable conduction path formed by aggregated MWNTs.