運用雙頻傅立葉頻譜轉換之即時光學動態三維輪廓量測技術

Dynamic Three-Dimensional Surface Profilometry Using Two-Frequency Fourier Transform

卓嘉弘(Chia-Hung Cho)

指導教授 ： 陳亮嘉

國立臺北科技大學/機電學院/自動化科技研究所/碩士(2007年)

https://doi.org/10.6841/NTUT.2007.00087

摘要

隨著高科技產業技術之成熟，業界對於微機電元件檢測之需求不斷提高，除了高精度外，速度之提升也日漸增益。過去之量測著重於靜態之檢測，但由於在靜態量測中，易受環境擾動而滋生量測誤差，舉凡各種製程與檢測設備如半導體製程設備、三次元量測儀及掃描式探針顯微設備，由於環境振動而影響精度或檢測成像解析度，因此即時量測或動態量測已成為未來發展之趨勢。其動態量測之技術可分為即時相移與傅立葉轉換輪廓術，即時相移主要以硬體為發展重點，以偏極片、波板及分光架構同時獲取三張以上之相位圖；而傅立葉轉換輪廓術主要以提高相位還原之速度為發展重點，其中通濾波皆採用遮罩之方式來獲取頻譜之資訊。
本文主要利用數位微鏡裝置投影其雙週期條紋，來發展動態三維形貌量測之系統，為了達到快速且避免振動之問題，以每秒60張以上之CCD搭配其雙頻傅立葉演算法進行量測，並針對其各級頻譜進行深入之探討，在中通濾波方面主要以頻譜之形貌來獲取，以避免過多之資訊遺失，達到其自動化之動態三維形貌量測，並利用等效週期有效提高其階高限制，其最大量測誤差可保持在5%以下。

關鍵字

自動化光學檢測(AOI) ； 傅立葉轉換 ； 表面形貌量測 ； 三維輪廓 ； 動態量測

並列摘要

This article presents an innovative method in rapidly acquiring accurate geometric 3-D surface morphology of micro electromechanical systems (MEMS) or devices. 3-D surface profilometry has become extremely important for high-tech manufacturing industries with applications in fields such as nanotechnology, biotechnology, broadband communication, and optoelectronics. In such applications, a considerable amount of research and development work has been carried out to increase the performances of 3-D measurement systems based on automatic optical inspection (AOI) techniques. One of significant issues in obtaining accurate dimensional information is dealing anti-vibration problems encountered in in-field inspection environment. To avoid employing expensive anti-vibration facilities and strict operation requirements in in-field 3-D measurement has become a critical problem to break through. At present, the technology can be divided real-time phase shifting and Fourier transform profilometry. Real-time phase shifting is an important direction on hardware innovation, which deploys polarizing filters, plant and beam splitters to obtaining more than three phase maps simultaneously. Fourier transform profilometry(FTP) focuses on entrancing the reconstruction speed for phase unwrapping. Its band-pass filter can be used to obtain the information in the frequency domain using the method of mask.
Therefore, in this research, an optical system incorporating with a digital micro-mirror device (DMD) for two-wavelength moire was developed to detect the object's morphology at a speed up to 60 frames or higher per second. The band-pass filter designed to obtain the phase information is investigated to optimize the 3D surface reconstruction in terms of measurement accuracy and efficiency. Using equivalent wavelength obtained can effectively increase the step height. The maximum measured error can be kept within 5% of the overall measuring range.

並列關鍵字

Automatic optical inspection (AOI) ； Fourier transform ； Surface profilometry ； Three dimensional measurement ； Dynamic measurement

參考文獻

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