精密薄膜光學檢測系統之檢測光源特性研究與分析

Characterization of Probe Lasers for Precision Thin Films Optical Inspection System

郭啟全(Chil-Chyuan Kuo) ； 趙金聖(Chin-Sheng Chao)

《建國科大學報》 29卷2期 (2010/01) Pp. 1-22

https://doi.org/10.6995/JCTU.201001.0001

摘要

檢測光源(probe laser)的功率穩定度與雷射光束飄移(beam wander)精確度(precision)是影響精密薄膜光學檢測正確性的重要因素，這一些因素也是評估檢測光源是否可以勝任於工業界生產線上長時間進行精密薄膜光學檢測之重點。本研究應用光束輪廓分析儀(beam profiler)，針對線上光學技術最常使用三種檢測光源：無線性偏極He-Ne雷射、線性偏極He-Ne雷射與Diode雷射進行特性評估與分析。實驗結果發現，線性偏極He-Ne雷射為精密薄膜光學檢測系統之最佳檢測光源，主要原因為雷射功率變化穩定度(stability)與雷射光束飄移精確度(precision)佳。He-Ne雷射功率變化穩定度與雷射光束飄移精確度優於Diode雷射，因此He-Ne雷射適合應用於薄膜光學檢測，但是必須於開機30分鐘以後才可開始進行檢測。線性偏極He-Ne雷射開機後第12小時，非常適合精密薄膜光學檢測，主要原因為雷射功率變化穩定度與雷射光束飄移精確度達到最佳值。對於長時間之精密薄膜光學檢測，本研究提出一個適合於工業界生產線上，進行長時間精密薄膜光學檢測之雙He-Ne雷射之光學檢測系統，此一系統中之每一隻He-Ne雷射可進行長達18小時之薄膜光學檢測，兩隻He-Ne雷射交替進行薄膜光學檢測，根據He-Ne雷射在正常操作條件下可使用之壽命，此系統可使用於精密薄膜光學檢測達半年至1年2個月之久。

關鍵字

檢測光源 ； 薄膜光學檢測系統 ； 穩定度 ； 精確度

並列摘要

The peak power density stability and beam wander precision of probe laser are important factors affecting the inspection results in precision thin-film optical measurements. These factors are also the core to evaluate the probe laser for in-line long-time operation of precision thin-film optical measurements. The peak power density and beam wander of three commonly used liner helium-neon (He-Ne) and random He-Ne, and diode laser as functions of time are investigated experimentally using beam profiler. It is found that the linear polarization He-Ne laser is a promising candidate of probe laser employed in precision thin-film optical measurements due to better peak power density stability and beam wander precision. Generally, both peak power density stability and beam wander precision of He-Ne laser are better than that of diode laser, but adequate warm-up of He-Ne laser for 30 minutes is required before thin-film optical measurements. After 12-hour operation, the linear polarization He-Ne laser is suitable for precision thin-film optical measurements because both peak power density stability and beam wander precision reach the minimum level. A system which is composed of two linear polarization He-Ne lasers for long-time operation of thin-film optical measurements is proposed in this paper. This system could be operated around half year to one year and two months in the precision thin-film optical measurements under the normal operating life of He-Ne laser by switching the probe laser every 18 hours.

並列關鍵字

probe lasers ； thin-film optical inspection system ； stability ； precision