High Speed Copper Electrodeposition for Through Silicon Via(TSV)

Copper electrodeposition in high aspect ratio via is one of the key technologies for 3D packaging. High speed copper electrodeposition is needed to achieve high TSV throughput. To inhibit the top surface of TSV, the ODT, was micro contact printed on the chip surface. ODT micro contact printing effectively inhibits the copper electrodepositon at the top surface. With SDDAC, V-shapes were formed in the via cross section and these V-shape shapes lead to bottom up via filling. Since the current density is lower for higher rotation disk rotation speed from the potential-current density curves, the copper electrodeposition is inhibited at the via openings. This leads to the V-shape cross sections. We succeeded to fill the 10 μm in diameter and 70μm in depth via within 37 minutes. This was achieved with shortening the off time to 100ms, ODT micro contact printing and adding 1mg/L of SDDACC additive.