Authors: Yoshinori Ejiri, Takehisa Sakurai, Yoshiaki Tsubomatsu, Kiyoshi Hasegawa Company: Hitachi Chemical Co., Ltd. Date Published: 10/14/2012
Abstract: We investigated the copper wire bonding reliability of electroless Ni/Pd/Au plating, electroless Ni/Au plating, and electrolytic Ni/Au plating on a semiconductor package substrate, comparing with the gold wire bonding. We found that the minimum gold thickness of electroless Ni/Pd/Au for the reliable copper wire bonding was 0.1 µm with a 0.1 ?m thick Pd film, and 0.2 ?m with a 0.03 ?m thick Pd film. For electroless Ni/Au and electrolytic Ni/Au, the minimum gold thickness was found to be 0.3 µm. These results indicate that electroless Ni/Pd/Au has the advantage of a lower minimum gold thickness over electroless Ni/Au and electrolytic Ni/Au for copper wire bonding. Thus, we have established electroless Ni/Pd/Au plating technology as beneficial in terms of cost and the amount of gold required for reliable copper wire bonding.