Title :
Evolution of intermetallic compounds at interface between PBGA solder ball and pads during laser reflow soldering
Author :
Tian, Yanhong ; Wang, Chunqing ; Pater, C.K. ; Liu, Deming
Author_Institution :
Nat. Key Lab. of Adv. Welding Production Technol., Harbin Inst. of Technol., China
Abstract :
This paper presents the evolution of Au-Sn and Cu-Sn intermetallic compounds at the interface between the PBGA solder ball and the PBGA metallization (Au/Ni/Cu and Cu pad) substrate during a first laser reflow followed by a second infrared reflow processes. A thin layer of AuSn4 and Cu3Sn intermetallic compounds were observed at the solder bump interface reflowed by laser when the metallization was Au/Ni/Cu and Cu respectively. The morphology of AuSn4 and Cu3Sn IMC were strongly dependent on the laser reflow power and heating time applied, and both changed after the secondary infrared reflow process. The AuSn4 layer formed at the interface in the first laser reflow process dissolved partially after the secondary infrared reflow process, and AuSn4 particles precipitated out at the eutectic cell boundary of the solder. The Cu3Sn IMC converted into a Cu6Sn5 layer at the interface after the secondary infrared reflow process, and Cu6Sn5 particles distributed randomly within the bulk solder.
Keywords :
ball grid arrays; copper alloys; crystal morphology; gold alloys; integrated circuit interconnections; integrated circuit metallisation; integrated circuit packaging; plastic packaging; reflow soldering; tin alloys; Au-Ni-Cu; AuSn4; AuSn4 particle precipitation; Cu pad; Cu3Sn; Cu6Sn5; PBGA metallization; PBGA solder ball/pad interface; eutectic cell boundary; heating time; infrared reflow processes; intermetallic compound evolution; intermetallic compound morphology; laser reflow power; laser reflow soldering; particle distribution; solder bump interface; Atherosclerosis; Electronics packaging; Gold; Infrared heating; Intermetallic; Laser transitions; Metallization; Power lasers; Reflow soldering; Temperature;
Conference_Titel :
Electronic Materials and Packaging, 2002. Proceedings of the 4th International Symposium on
Print_ISBN :
0-7803-7682-X
DOI :
10.1109/EMAP.2002.1188832