Investigations of fluxless flip-chip bonding using vacuum ultraviolet and formic acid vapor surface treatment

N. Unami, H. Noma, K. Sakuma, A. Shigetou, S. Shoji, J. Mizuno

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Citations (Scopus)

Abstract

We studied the effects of surface treatment using vacuum ultraviolet (VUV) and formic acid vapor for SnCu-Au flip-chip bonding. Sn-rich solder bumps are widely used for flip-chip interconnections because of low melting temperature and high mechanical strength. For fine pitch interconnections, surface modification is needed before the bonding process. X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES) were used to investigate Sn surfaces. The results showed how the VUV/O 3 surface treatment removes the carbon-based organic contaminants from the Sn surfaces and the formic acid treatment reduces the metal oxides of Sn. Combination of VUV/O 3 and formic acid treatments improved shear strength of a bonded sample. The average shear strength of each bump with VUV/O 3 and/or formic acid treatment is about twice that of a bump with no treatment.

Original languageEnglish
Title of host publicationAPM 2011 Proceedings - 2011 International Symposium on Advanced Packaging Materials
Pages220-225
Number of pages6
DOIs
Publication statusPublished - 2011
Event2011 International Symposium on Advanced Packaging Materials, APM 2011 - Xiamen, China
Duration: 2011 Oct 252011 Oct 28

Publication series

NameProceedings - International Symposium on Advanced Packaging Materials
ISSN (Print)1550-5723

Conference

Conference2011 International Symposium on Advanced Packaging Materials, APM 2011
CountryChina
CityXiamen
Period11/10/2511/10/28

ASJC Scopus subject areas

  • Industrial and Manufacturing Engineering
  • Materials Science(all)

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    Unami, N., Noma, H., Sakuma, K., Shigetou, A., Shoji, S., & Mizuno, J. (2011). Investigations of fluxless flip-chip bonding using vacuum ultraviolet and formic acid vapor surface treatment. In APM 2011 Proceedings - 2011 International Symposium on Advanced Packaging Materials (pp. 220-225). [6105704] (Proceedings - International Symposium on Advanced Packaging Materials). https://doi.org/10.1109/ISAPM.2011.6105704