Journal of Electrical Engineering and information Science

The Korean Institute of Electrical Engineers (대한전기학회)
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The Optimum Condition of Anisotropic Bulk(10) Si Etching with KOH for High Selectivity and Low Surface Roughness

  • Lim, Hyung-Teak (School of Electrical Engineering, Seoul National University) ;
  • Kim, Yong-Kweon (School of Electrical Engineering, Seoul National University) ;
  • Lee, Seung-Ki (Department of Electrical Engineering, Dankook University)
  • Published : 1997.10.01
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Abstract

In this paper, the optimum condition of (110) Si etching with the potassium hydroxide(KOH) etchant is presented. Although several researches on (110) Si anisotropic etching have been studied, there has been lack of effects of mask quality and etching conditions on the selectivity and the roughness o the etched surface. Three kinds of masks (film, emulsion and E-beam mask) were used in order to verify the effect of etching properties. Anisotropic bulk etching depends on the crystalline orientation and the concentration and temperature of the etchant. In order to investigate the effect of etching conditions on selectivity and the roughness of the etched surface, the concentration of the etchant was varied from 35 to 45 per cent in weight with increments by 5 per cent and the temperature was changed from 70 to 90$^{\circ}C$ with increments by 10$^{\circ}C$. The combination of the temperature of 70$^{\circ}C$ and the concentration of 40wt.% was found to be the optimum etching condition for high selectivity. Etched surfaces show minimum surfaces show minimum surface roughness at a temperature of 80$^{\circ}C$ and a concentation of 40wt.%. Comb structures with various comb widths were fabricated and the lengths of the combs wree measured with several etching time durations. A micro comb structure 525$\mu\textrm{m}$ high was fabricated for MEMS application.

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References

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