Development of UV-curable anisotropic conductive film by epoxy resin

Abstract

The demand for Anisotropic Conductive Films (ACF) has significantly increased due to the growth in usage of Liquid Crystal Display (LCD) and other electronics. An ACF is a polymer adhesive that contains conductive particles in the polymer matrix. It provides good electrical connection for the circuits in the perpendicular direction of film and excellent adhesion to electronics substrates while providing electrical insulation in all other direction. The most common bonding type of ACF is the heat-compression curing process. However, the high bonding temperature (>160℃) can cause a negative impact on the performance of ACF such as the warpage effect and heat damage to the substrates. In this project, an UV-curable ACF was developed by using low-cost epoxy resin bisphenol A diglycidyl ether (DGEBA). The performances of Epoxy resin E44 and E51 are evaluated. A list of characterization including 4-point probe resistance measurement, 180° adhesion test, Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric analysis (TGA), Differential scanning calorimetry (DSC), 85℃/85% relative humidity test and ANOVA were conducted to investigate contact resistance, adhesion strength, degree of curing, thermal stability, glass transition temperature, and aging performance respectively. Based on our result, the optimized ACF formulation includes the following components: epoxy resin E51, phenoxy resin PKHH, triarylsulfonium hexafluoroantimonate salts and Ag/Ni/PS conductive particles. Economic analysis was also conducted for the profitability of the formulation. The optimized ACF formulation is profitable depending on the gross margin and others production costs.

Date of Award	2020
Original language	English
Awarding Institution	The Hong Kong University of Science and Technology