Laser recovery of grinding-induced subsurface damage in the edge and notch of a single-crystal silicon wafer

Keiichiro Niitsu, Yu Tayama, Takatoshi Kato, Jiwang Yan

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

The edges and notches of silicon wafers are usually machined by diamond grinding, and the grinding-induced subsurface damage causes wafer breakage and particle contamination problems. However, the edge and notch surfaces have large curvature and sharp corners, thus it is difficult to be finished by chemo-mechanical polishing. In this study, a nanosecond pulsed Nd:YAG laser was used to irradiate the edge and notch of a boron-doped single-crystal silicon wafer to recover the grinding-induced subsurface damage. The reflection loss and the change of laser fluence when irradiating a curved surface were considered, and the damage recovery behavior was investigated. The surface roughness, crystallinity, and hardness of the laser recovered region were measured by using white light interferometry, laser micro-Raman spectroscopy, and nanoindentation, respectively. The results showed that after laser irradiation the damaged region was recovered to a single-crystal structure with nanometric surface roughness, and the surface hardness was also improved. This study demonstrates that laser recovery is a promising post-grinding process for improving the surface integrity of the edge and notch of silicon wafers.

Original languageEnglish
Article number015013
JournalSurface Topography: Metrology and Properties
Volume7
Issue number1
DOIs
Publication statusPublished - 2019 Feb 7

Keywords

  • curved surface
  • laser recovery
  • single-crystal silicon
  • subsurface damage
  • surface topography
  • wafer edge

ASJC Scopus subject areas

  • Instrumentation
  • Process Chemistry and Technology
  • Surfaces, Coatings and Films
  • Materials Chemistry

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