Journal of the Korean Society for Precision Engineering (한국정밀공학회지)

Korean Society for Precision Engineering (한국정밀공학회)
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A New Method of Noncontact Measurement for 3D Microtopography in Semiconductor Wafer Implementing a New Optical Probe based on the Precision Defocus Measurement

비초점 정밀 계측 방식에 의한 새로운 광학 프로브를 이용한 반도체 웨이퍼의 삼차원 미소형상 측정 기술

  • 박희재 (서울대학교 공과대학 기계공학부) ;
  • 안우정 (서울대학교 대학원 기계설계학과)
  • Published : 2000.01.01
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Abstract

In this paper, a new method of noncontact measurement has been developed for a 3 dimensional topography in semiconductor wafer, implementing a new optical probe based on the precision defocus measurement. The developed technique consists of the new optical probe, precision stages, and the measurement/control system. The basic principle of the technique is to use the reflected slit beam from the specimen surface, and to measure the deviation of the specimen surface. The defocusing distance can be measured by the reflected slit beam, where the defocused image is measured by the proposed optical probe, giving very high resolution. The distance measuring formula has been proposed for the developed probe, using the laws of geometric optics. The precision calibration technique has been applied, giving about 10 nanometer resolution and 72 nanometer of four sigma uncertainty. In order to quantitize the micro pattern in the specimen surface, some efficient analysis algorithms have been developed to analyse the 3D topography pattern and some parameters of the surface. The developed system has been successfully applied to measure the wafer surface, demonstrating the line scanning feature and excellent 3 dimensional measurement capability.

Keywords

References

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