Internal profile reconstruction of microstructures based on near-infrared light transmission reflection interferometry with optical path compensation
高深寬比微結構的底部及側壁形貌重構是微機電系統領域亟待解決的一個問題。本文提出光程補償近紅外光透射反射干涉技術重構微結構內部形貌的方法, 所采用的近紅外光干涉技術將白光干涉系統中的光源擴展至近紅外光源, 將反射干涉技術擴展至透射反射干涉技術, 近紅外光干涉測量系統由近紅外光光源、干涉顯微鏡、紅外光CCD、高精度壓電陶瓷和數據采集系統組成。設計了具有兩個臺階的GaAs半導體微結構待測樣品, 采用近紅外光垂直掃描干涉法并通過光程補償, 重構了微結構的內部三維形貌, 并與掃描電鏡結果進行對比。光程補償近紅外光透射反射干涉技術測量的臺階相對高度分別為2132 μm和0766 μm, 與掃描電鏡和近紅外光反射干涉測量結果基本一致, 分別對應216%和268%的相對誤差。測量結果表明, 該測量系統能夠測量高深寬比微結構底部及側壁形貌。
The bottom and sidewall profile reconstruction of microstructures with a high aspect ratio is a problem that urgently needs to be solved in the field of MEMS(Micro-Electro-Mechanical system). Microstructures profile reconstruction method is presented based on near-infrared light transmission reflection interferometry with optical path compensation(OPC), which is extended from white light to near-infrared light and from reflection interference to transmission interference. The near-infrared light transmission interferometry system is composed of a near-infrared light source, an interference microscope, an infrared light CCD, piezoelectric ceramics with high accuracy and a data acquisition system. A GaAs sample microstructure with two steps was designed and the method of vertical scanning interference of near-infrared light with OPC was adopted to reconstruct the internal profile of a microstructure, which was then compared with the results of scanning electron microscopy(SEM). Test results show that the relative heights of the measured microstructure steps using near-infrared light transmission reflection interferometry were 2132 μm and 0766 μm with 216% and 268% relative errors, respectively, which agree with the results of SEM and that of the near-infrared light reflection interferometer. The measurement system has the ability to reconstruct the bottom and sidewall profile of microstructures with a high aspect ratio.
基金項目：國家自然科學基金青年基金(No.11705107); 山西省科技攻關項目(No.2015031002-1); 山西大同大學博士學位研究基金(No.2014B15)
韓丙辰：山西太原師范學院 物理學院, 山西 太原 030619
備注：SHI Jian-hua(1978—), male, Associate Professor, from Ningwu County, Shanxi Province, Master′s Research Degree. Present: Deputy Director of the Teaching Evaluation and Supervision Center, and teacher at the Institute of Physics and Energy, mainly engaged in the research of optical processing involving image processing.
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