Effect of laser irradiation on generation and growth of whiskers in tin-electroplated film

Yutaka Mitooka, Koji Murakami, Makoto Hino, Masao Takamizawa, Jun Takada

Research output: Contribution to journalArticle

Abstract

In order to suppress generation and growth of whiskers, the effect of laser irradiation on tin-electroplated film on copper was studied by scanning electron microscopy and X-ray diffraction method. In the case of as-plated film, whiskers were generated on the electroplated tin film of 1 mμ thickness within 432 ks. Residual stress of this film and the number of whiskers increased with the amount of copper-tin intermetallic compounds (Cu6Sn 5) which developed between the plated film and the copper substrate. On the other hand, in electroplated tin film subjected to diode laser of 300 W for 100 to 1000 ms, no whiskers were formed even after 10 Ms. Residual stress of tin after laser irradiation was tensional at first, then, the stress did not change appreciably after 2.6 Ms. Uniform layer of Cu6Sn5 was formed immediately after laser irradiation, and the morphology showed no meaningful change even after 10 Ms. Whiskers are thought to be suppressed by covering the interface between tin and copper with layer of Cu 6Sn5 and by reducing nonuniformity of stress field.

Original languageEnglish
Pages (from-to)2247-2252
Number of pages6
JournalMaterials Transactions
Volume50
Issue number9
DOIs
Publication statusPublished - Sep 1 2009

Keywords

  • Intermetallic compound
  • Laser irradiation
  • Residual stress
  • Tin plating
  • Whisker

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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