Effect of Surface Treatment on the Mechanical Strength of Ultrasonically Bonded Chip on Copper-Coated Glass for Ultra-Fine Pitch Application in Microelectronics

Abstract

This study was focused on the effect of surface treatment on the mechanical strength of ultrasonically bonded copper chips on copper-coated glass. The plasma treatment was performed with two different gases, either N(2) + O(2), or N(2) + H(2), for treatment times up to 18s. Wet treatment was also carried out with 5vol% H(2)SO(4). Surface analysis was carried out after the treatment using Auger electron spectroscopy (AES) and it was found that treatment conditions greatly affected the joint strength. Wet cleaning with 5vol% H(2)SO(4) effectively removed oxides from the Cu surface, while addition of O(2) gas into N(2) gas plasma was good for removing carbides. The treatment conditions greatly affected the removal of contaminants on the Cu surface and the bondability between Cu bumps and Cu-coated glass substrates. (C) 2009 The Japan Society of Applied Physics