Influence of surface morphology to laser cleaning efficiency

Y. W. Zheng, Y. F. Lu, Z. H. Mai, W. D. Song

Research output: Contribution to journalConference article

1 Scopus citations

Abstract

Laser cleaning is an effective cleaning method that can be widely used in microelectronic industry. Mechanisms of laser induced removal of particulate contaminants from solid substrates, such as Si wafer, are of great concern. The previous works on laser cleaning are mostly based on perfectly flat surface model, while few of them are objected to the influence of surface morphology. In the IC process, however, the Si surface morphology will change dramatically after few steps of processing, therefore its influence to laser cleaning efficiency is inevitable. In this experiment, the cleaning efficiencies of 2.5 and 1.0 μm spherical silica particles from Si with different surface morphologies are investigated. These surfaces were achieved by anisotropic etching of Si wafers in KOH solvent, with etching times raging from 1 minute to 30 minutes. Atomic force microscope (AFM) observation showed the Rp-v roughness of thus-processed Si surfaces ranges from 1.6 nm to 70 nm, and rms roughness ranges from 0.1 nm to 9.0 nm. For both kinds of particles, the cleaning efficiencies decrease with increasing surface roughness. The possible reason is that the rough surface may buffer the sudden thermal expansion of the substrate, making the particles more difficult to be removed.

Original languageEnglish (US)
Pages (from-to)287-296
Number of pages10
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume3898
StatePublished - Dec 1 1999
EventProceedings of the 1999 Photonic Systems and Applications in Defence and Manufacturing - Singapore, Singapore
Duration: Dec 1 1999Dec 3 1999

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ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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