학술논문
A study about solder bumping process by using the electro-plating method
Document Type
Conference
Author
Source
Advances in Electronic Materials and Packaging 2001 (Cat. No.01EX506) Electronics materials and packaging Electronic Materials and Packaging, 2001. EMAP 2001. Advances in. :170-177 2001
Subject
Language
Abstract
Solder bump whose pitch is 150-300 /spl mu/m was fabricated on Si substrate by electroplating with the medium thickness (/spl sim/30 /spl mu/m) photoresist. TiW/Cu/Cu mini bump was used as a UBM (under bump metallurgy) layer. TiW (0.3 /spl mu/m)/Cu (0.7 /spl mu/m) was deposited by sputtering and Cu mini bump (5-15 /spl mu/m) was formed by electroplating. After UBM formation, subsequently, solder bump of mushroom shape was formed by electroplating. In electroplated solder bumping process, the control of the composition is one of the most important key technologies. However, during the formation of a solder mushroom, the composition of solder bump changes due to the variation of plating area. In order to obtain the uniform solder composition with the variance of plating area, applied current was controlled under the consideration of plating area. By controlling the applied current, the composition of solder bump can be controlled within 4%. Solder ball size after reflow could be controlled by calculating the amount of plated solder and measuring the mushroom diameter.