Study on the behaviors of Cu filling in special through-silicon-vias by the simulation of electric field distribution

• A new kind of chip with a special TSV structure was used in this paper.
• ANSYS® was used to simulate the overall electric field distribution.
• Simulation and electroplating shows bottom-up filling of conventional TSV.
• Deposition of special TSV is mainly controlled by the electric field distribution.

The filling mechanism of a special through silicon vias (TSV) structure is investigated by electrochemical test and simulation technique compared with the conventional TSV structure in this paper. The effects of additives in methanesulfonic solution are briefly studied by cyclic voltammetry to obtain the suitable copper plating condition for conventional TSV. The electric field distribution in the special TSV during the electrodeposition has been simulated by the software ANSYS. Different from the conventional TSV, the electric field gathered at the bottom of the via in the initial stage of special TSV, which benefit the bottom up filling in the via. And after the deposited copper spread to the whole surface of the chip, the electric field distribution becomes similar to the conventional TSV. With the help of the additives, the void free copper electrodeposition in special TSV was finally achieved.

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