Development of hybrid system of double-sided- and tandem- interferometer for precise measurement of refractive index and its temperature dependence of silicon

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K20421
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0301:Mechanics of materials, production engineering, design engineering, fluid engineering, thermal engineering, mechanical dynamics, robotics, aerospace engineering, marine and maritime engineering, and related fields
• Research Institution: National Institute of Advanced Industrial Science and Technology
• Principal Investigator: KAWASHIMA Natsumi 国立研究開発法人産業技術総合研究所, 計量標準総合センター, 研究員 (10908635)
• Project Period (FY): 2021-08-30 – 2023-03-31
• Keywords: 屈折率 / 分散 / 温度依存性 / 厚さ計測 / 広帯域光干渉 / レーザー計測 / 干渉計測 / 光計測

Outline of Final Research Achievements

The aim of this study is to develop a hybrid interferometer capable of simultaneously measuring geometric thickness by a double-sided interferometer using visible laser light and optical thickness by a tandem interferometer using near-infrared low-coherence light to obtain the refractive index of silicon and its temperature dependence with high accuracy.
We confirmed the principle of a tandem low-coherence double-sided interferometer using a low-coherence light source in the visible light. A double-sided interferometer that can measure the geometric thickness of a silicon wafer was developed and connected to an interferometer that compensates for an optical path difference greater than the coherence length. It was confirmed that interference fringe images required to obtain the geometrical thickness can be acquired even though there is an optical path difference greater than the coherence length.

Free Research Field

光計測

Academic Significance and Societal Importance of the Research Achievements

提案するハイブリット光学系で屈折率値及びその温度依存性が高精度に測定できれば、産業界における分光干渉計測の高精度化、高信頼性化に資するとともに、シリコンの物性値に新たな知見を加えることが期待される。