S-Space College of Engineering/Engineering Practice School (공과대학/대학원) Dept. of Mechanical Aerospace Engineering (기계항공공학부) Theses (Master's Degree_기계항공공학부)
Improvement of Measurement Repeatability for White Light Phase Shifting Interferometry by Phase Compensation
위상보정을 이용한 백색광 위상 천이 간섭계에서의 반복능 향상에 관한 연구
- 공과대학 기계항공공학부
- Issue Date
- 서울대학교 대학원
- White Light Phase Shifting Interferometry (WLPSI); Phase error; Phase compensation; Repeatability
- 학위논문 (석사)-- 서울대학교 대학원 : 기계항공공학부, 2016. 2. 박희재.
- In this thesis, the measurement repeatability of White Light Phase Shifting Interferometry (WLPSI) is improved using phase compensation algorithm. In WLPSI, phases which include height information of a target can be obtained by calculating intensities of captured images. The mechanical vibration of a stage, however, could affect each phase of an image. In consequence of the vibration, phase errors are implicated at each phase and these errors could bring out the unstable repeatability. In order to enhance the repeatability, a phase compensation method is introduced based on the phase variation theory.
At the ideal measurement, a set interval of PZT actuator is equal when scanning. Based on the theory, the phase variation is proportional to the scanning interval. Therefore, the phase compensation method can be applied using the relation between the phase variation and the interval.
In order to verify the performance of the suggested method, measurement of three types of micro patterns and Standard Step Height Sample with vibration is carried out. As a result, the repeatability of measurement is improved by applying proposed phase compensation method.