Effects of solvents, activators, and additives on sintering properties of Cu paste for die attach

초록

Cu sintering has attracted considerable attention because of its low electrical resistance, high thermal conductivity, low resistance to ion migration, and reasonable price. But, the unique oxidation tendency of Cu is the leading cause of hindering Cu sintering. Several methods have been proposed to solve this oxidation problem. In this study, Cu paste for die attachment was prepared by selecting appropriate solvents, activators, and additives. The sintering properties and bonding strength of Cu paste were governed by the molecular weight and the chain length of the solvent. Among various solvents, the highest shear strength was observed in the case of polyethylene glycol (PEG) solvent. The addition of dicarboxylic acid allowed for a faster reduction rate of copper oxide, which improved Cu sintering performance. A Cu binder with a stable reduction reaction and storage stability was developed by applying a phenol-based antioxidant.

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