Formation of fine pitch solder bump with high uniformity by the tilted electrode ring

경사진 전극링을 이용한 고균일도의 미세 솔더범프 형성

The bubble flow from the wafer surface during plating process was studied in this paper. The plating shape in the opening of photoresist becomes gradated shape in the fountain plating system, because bubbles from the wafer surface are difficult to escape from the deep openings, vias. So, we designed the tilted electrode ring contact to get uniform bump height on all over the wafer and evaluated the film uniformity by SEM and ${\alpha}-step$. In ${\alpha}-step$ measurement, film uniformities in the fountain plating system and the tilted electrode ring contact system were ${\pm}16.6%,\;{\pm}4%$ respectively.