白光相移干涉術之三維表面量測

Abstract

研究白光相移干涉術進行三維表面量測的應用。分別使用傳統PZT相移法與消色差相移法進行量測，比較討論兩種相移法的結果。 量測系統採用的架構為Linnik式干涉儀，所使用的白光為鹵素燈，涵蓋可見光範圍的多波長光源。然而考慮到理論上推導光譜為高斯功率光譜密度分佈的多色光源，因此加入窄帶通濾波片(中心波長629.5nm)與寬帶通濾波片(中心波長550nm)，以能為了更精確滿足理論要求。為了檢驗量測結果，與ZYGO儀器所量測的結果進行比較。 使用相移法，一般可達非常精密的縱向解析，但還是有著縱向深度量測的限制。如能結合白光同調長度短的特性，進行最大強度位置掃描，便可大大提升縱向量測範圍。

In order to study the application of white-light phase-shifting interferometry (PSI) in three dimension surface measurement ,we use traditional PZT phase shifting and achromatic phase shifting .We compare and discuss the results from both the phase-shifting methods. The measurement system is a Linnik interferometer. The light source is a halogen lamp,which is a polychromatic light source,covering the visible spectral range . In the theory we assume that the polychromatic light source has a Gaussian power spectral density, so we use a narrow bandwidth filter with central wavelength 629.5nm and broad bandwidth filter with central wavelength 550nm, to satisfy the theoretical requirement. To verify our measurement results,we compare the surface profiles measured by our interferometer with that by Zygo instrument. By using phase shifting, we can achieve high vertical resolution, but have a limited vertical depth. If we consider the characteristics of the short coherence length of white-light and make a vertical scanning to find the location of maximum intensity, we can greatly improve the measurement of vertical range.