The effect of pretreatment process on electroless nickel bumping for different Al pads

Xiao Chen Fu, Guo Wei Xiao, Pui Chung Law, Philip Ching Ho Chan

Research output: Chapter in book / Conference proceedingConference article published in proceeding or bookAcademic researchpeer-review

Abstract

We present a study on optimization of pretreatment process of the electroless plating to obtain good aspect and process steadiness of nickel UBM on different aluminum surface morphology. Pitch 250um and circular Al pads with 85um opening in the passivation layer were prepared for our study. Six kinds of aluminum pads were produced by the sputtering system: Varian-3180. The compounds of the Al targets were 98.95%Al-l%Si-0.05%Ti in the Varian sputtering system and some set parameters of sputtering system were varied, the heterogeneous surface morphology of aluminum samples was gained in our research. All the samples underwent the electroless zinc/nickel/gold plating with tow kinds of different pretreatments. The effect of aluminium surface morphology on the nickel UBM was observed. The results demonstrated that the preircatment of Al pad surface by heat sodium hydroxide and mixed acid provided denser zinc seeds. That led to better electroless nickel plating. The reasonable and acceptable pretreatment of Al pad surface is critical for the nickel UBM.
Original languageEnglish
Title of host publicationInternational Conference on Solid-State and Integrated Circuits Technology Proceedings, ICSICT
Pages603-606
Number of pages4
Publication statusPublished - 1 Dec 2004
Externally publishedYes
Event2004 7th International Conference on Solid-State and Integrated Circuits Technology Proceedings, ICSICT 2004 - Beijing, China
Duration: 18 Oct 200421 Oct 2004

Conference

Conference2004 7th International Conference on Solid-State and Integrated Circuits Technology Proceedings, ICSICT 2004
CountryChina
CityBeijing
Period18/10/0421/10/04

Keywords

  • Electroless plating
  • Flip-chip
  • Micro-etch
  • UBM

ASJC Scopus subject areas

  • Engineering(all)

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