Title :
A bump reflow process with alcohol
Author :
Liu, Y. ; Zeng, S. ; Ma, J. ; Kuang, Y.
Author_Institution :
Dept. of Mater. Sci. & Eng., Tsinghua Univ., Beijing, China
Abstract :
This paper presents Pb-Sn bump reflow processing with alcohol. In one process, before a mild acid is used to remove the oxide and contamination layers on the solder surface, the bumps are reflowed in the alcohol. In the another process, the bumps are reflowed in the alcohol without the same pretreatment. By comparing the morphography, microstructure, and bump content with or without pretreatment, it is found that the mild acid helps to remove the reactive product derived from etching UBM. The function of alcohol is analysed. It is found that the alcohol prevents the bump from oxidizing, the alcohol convection strips off the oxide and contamination layers, and the alcohol acts as a weak reducing agent
Keywords :
crystal microstructure; crystal morphology; flip-chip devices; integrated circuit packaging; lead alloys; microassembling; oxidation; reduction (chemical); reflow soldering; surface contamination; tin alloys; Pb-Sn bump reflow processing; PbSn; UBM etching; alcohol; alcohol convection; bump content; bump oxidation prevention; bump reflow process; contamination layer stripping; flip chip interconnects; mild acid contamination layer removal; mild acid oxide layer removal; oxide layer stripping; pretreatment; reactive product removal; solder surface; weak reducing agent; Chemical analysis; Etching; Materials science and technology; Microstructure; Optical microscopy; Packaging; Strips; Surface contamination; Surface cracks; Tin;
Conference_Titel :
Electronic Materials and Packaging, 2000. (EMAP 2000). International Symposium on
Conference_Location :
Hong Kong
Print_ISBN :
0-7803-6654-9
DOI :
10.1109/EMAP.2000.904150
