精密雷射微加工在生物醫學、電子及材料加工等領域的科學研究和工業應用中扮演著重要的地位。它們依賴對加工深度的高精確控制，尤其是加工盲孔或差結構的雷射鑽孔。在本篇論文我們提出一種雷射微加工即時監測系統。為即時監測雷射加工深度系統，我們利用一共焦結構(confocal structure)和一光偵測器(photodetector)，發展一測量微小孔洞深度的方法，此方法可達微米(μm)的精確度。經實驗証明此方法對一直徑約100微米、深度為數十微米的孔洞具有優於95%的深度準確度。並利用兩個透鏡組去證實，適當地選擇共焦結構的透鏡焦距可以有效地增加位置的敏靈度。此方法可以適用於不同結構的盲孔雷射鑽孔，例如單一材料或不同材料的多層結構，以及不同材料，例如合金和矽晶片，也非常容易和工業及研究導向的雷射加工流程整合。

The precision laser micro-machining plays an important role in the science research and industrial applications among the biomedical, electronics, and material processing fields. They rely on high precise control of the process depth, especially laser drilling for blind-hole or heterodyne structure. In this paper, we present a on-line monitoring of laser micromachining system. A micron-precision micro-hole depth detection scheme has been developed which utilizes a confocal structure and a photodetector. This scheme is experimentally confirmed to posses an accuracy of greater than 95% for micro-holes on the order of one-hundred microns in diameter. And utilize two lens groups to verify, chosen the lens focus of the confocal structure appropriately can increase the position effectively. This method can be suitable for different structure, such as single substructure or multilayer bulk heterodyne structure, and for difference material, alloy and silicon wafer, and could be easily be integrated for the control of industrial and research oriented laser micro-machining process.

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