关键词: 种子层, 先进封装, 铜蚀刻, 电偶腐蚀, 凸点

Abstract: In the wet etching process of copper seed layer for advanced packaging, there is an anisotropic phenomenon in the etching of electroplated copper coating.The results of the study have been shown that in the etching liquid system of phosphoric acid and hydrogen peroxide, the amount of electroplated copper etching of bumps due to galvanic corrosion is about 4.9 times the amount of copper seed layer etching.By analyzing the energy spectrum data and etching effect of the tin and nickel coatings on the bump, it is found that there are passivation layers on the surface of the tin and nickel coatings in the bump structure, which results in the etching amount of the tin and nickel coatings being much lower than that of the copper coatings.In the etching solutions with different additives, the effect of inhibiting the galvanic corrosion of the copper coatings on the bumps can be achieved by complexing copper or destroying the passivation layers on the surface of the tin and nickel coatings.Among them, the composite additive reduces the amount of transverse etching of the copper coating on the bump by about 82%, and there is no risk of residue from the additive.

Key words: seed layer, advanced packaging, copper etching, galvanic corrosion, bump