Microvia Filling with Nickel-Tungsten Alloy to Decrease the Coefficient of Thermal Expansion of Electronic Circuit Interconnections

作者：Ying‐Chen Lin, Hening Huang, H.-W. Wang, Wei‐Ping Dow, Jing‐Yuan Lin, P.‐H. Chang, Heui Chang Lee · 发表于：ECS Electrochemistry Letters · 年份：2015 · DOI：10.1149/2.0031509eel · 被引用次数：11 · 研究领域：3D IC and TSV technologies、Electronic Packaging and Soldering Technologies、Electrodeposition and Electroless Coatings

A nickel-tungsten alloy plating formula was developed to electrochemically fill the microvias of printed circuit boards and the through-silicon vias (TSVs) of wafers. The plating solution was composed of Ni(SO 3 NH 2 ) 2 , citric acid, sodium citrate, Na 2 WO 4 , chloride ions, and 2-mercapto-5-benzimidazolesulfonic acid. A void-free Ni-W superfilling of a microvia and a TSV were achieved. The tungsten content in the filled alloy varied from 1.5 atom% to 5.5 atom%, depending on the plating temperature. The coefficient of thermal expansion of the filled Ni-W was theoretically calculated according the tungsten content, which was lower than that of copper.