プリント配線板におけるビア底部の再結晶化に及ぼす 無電解銅めっき皮膜中のニッケル含有率の影響

Abstract

Electroless copper plating is an important process to improve the electrical reliability at the bottom of the via. In this study, the effects of nickel ions added to the electroless copper plating bath on throwing power, electrical conductivity, and the recrystallization of electro copper plating films were investigated. When the electroless copper plating film to be the seed layer had high purity and low film thickness, the crystal grains of the inner layer copper and the electro copper plating showed continuity with the recrystallization at room temperature. The co-deposition of nickel in the electroless copper plating film increased the sheet resistance and hindered the continuity with the crystal grains of the inner layer copper. When continuity with the crystal grains of the inner layer copper occurred, the solder heat resistance test showed high electrical reliability.