Electrodeposition of Nanotwin Cu by Pulse Current for Through-Si-Via (TSV) Process

Abstract

Recently, the through-Si-via (TSV) had been focused as an optimal solution for interconnecting the 3-dimensionaly stacked semiconductor devices. One of core processes in the TSV technology is the Cu filling process which electrochemically forms the Cu in the via with high aspect ratio. The nanotwin Cu is effective candidate for replacing the conventional electrodeposited Cu due to its ultrahigh mechanical strength and good electrical conductivity. In this work, the formation of the nanotwin Cu in the TSV by applying pulse current was systematically studied. Also, TSV filling behavior by electrodeposition with pulse current was compared with direct current. The variation of mechanical properties as well as the electrical resistivity of electrodeposited Cu by the pulse current also investigated.

Electrodeposition of Nano-Twinned Cu and their Applications in Electronics

“…Previous research suggests that internal TSV twin formation is one solution to this problem. [90][91][92][93] Yoo et al used galvanostatic PED in commercial-additivecontaining CuSO 4 -H 2 SO 4 electrolytes to fill TSVs with twinned Cu and optimized the filling by changing t on , t off , and the PED frequency. 90 Under the optimal PED conditions, 6 μm-diameter × 60 μm-deep TSVs were filled with twin lamellas (Fig.…”