Title :
Solder bump forming using micro punching technology
Author :
Kato, Yoshimasa ; Ueoka, Yosihito ; KOno, Eiichi ; Hagimoto, Eiji
Author_Institution :
Lab. of Production Mater. Eng., NEC Corp., Kawasaki, Japan
Abstract :
A new solder bump forming method using a micro punching technology was developed for flip chip interconnection. The aim of a new method is to form an accurate bump in volume, with a low cost. The micro punching technology can be applied to various kinds of solder material and can form a very small diameter bump. A punched cylindrical piece has minimum 50 μm diameter and 30 μm thickness. Two kinds of solder bump forming methods were developed. One is direct method, that a punched solder piece is directly pressed on a substrate. Various material solder bumps were formed by this method. Another is transferring method, that punched solder pieces are pressed on a temporary plate and then transferred onto a substrate. Using transferring method, pressure to a bump is 20 mN or less. Solder bumps formed by the micro punching technology have 3 μm height accuracy after reflow
Keywords :
flip-chip devices; integrated circuit interconnections; reflow soldering; direct method; flip chip interconnection; micro punching technology; reflow; solder bump forming; transferring method; Assembly; Bonding; Costs; Flip chip; National electric code; Packaging; Punching; Shape; Testing; Wire;
Conference_Titel :
Electronic Manufacturing Technology Symposium, 1995, Proceedings of 1995 Japan International, 18th IEEE/CPMT International
Conference_Location :
Omiya
Print_ISBN :
0-7803-3622-4
DOI :
10.1109/IEMT.1995.541007
