即時薄膜光學參數量測系統之開發

Development of in situ optical parameters measurement system in thin film

黃富榮(Fu-rong Huang)

指導教授 ： 李朱育

國立中央大學/工學院/光機電工程研究所/碩士(2014年)

摘要

本論文是在開發薄膜成長率、折射率，以及消光係數之即時量測系統。用於薄膜製程時，即時監控薄膜參數，有效提高製程品質。基於干涉原理與薄膜光學理論，以一道雷射光垂直入射薄膜，在薄膜上表面與下表面產生兩道反射光，反射光由光偵測器接受後，藉由入射光強與反射光強之比，獲得薄膜反射率曲線，再透過軟體計算出薄膜光學參數。
實驗分別在空氣膜以及濺鍍機鍍膜上進行薄膜參數量測。於空氣膜實驗中，利用楔形稜鏡與載玻片相隔一段距離，以此距離中之空氣為薄膜，透過壓電陶瓷(PZT)位移平台推動載玻片模擬薄膜成長。濺鍍實驗中，使用磁控射頻濺鍍系統，在矽基板上濺鍍氧化鋅薄膜。以上各項實驗數據，通過程式軟體量測並計算出薄膜光學參數。另外會對所量測到之反射率曲線進行弦波擬合，分別擬合出週期、振幅，以及直流項，再經由公式轉換為成長率、折射率，以及消光係數達到即時監控之目的。

關鍵字

薄膜 ； 反射率 ； 成長率 ； 折射率 ； 即時量測 ； 弦波擬合

並列摘要

The purpose of this paper is to measure the growth rate and optical parameters of the thin film during epitaxial growth. Measurements are based on interferometry and thin film theorem. Using a Laser Diode light source propagating into thin film, the thin film reflected light will be measured by detector. Then the signal of reflected light is transmitted to a PC via a DAQ card and particular algorithms developed to solve for the optical factors growth rate G, refractive index n and extinction coefficient k.
We design an air layer that can change its thickness by using a piezoelectric (PZT) actuator. Another experiment, ZnO thin film is deposited on Silicon wafer by radio-frequency (RF) sputtering system. When thin film grows, the reflectance curve will be measured. Through the special equations, we can obtain the growth rate, refractive index and extinction coefficient. Besides, the curve fitting method has been proposed to fit the reflectance curve. This method aims to in situ monitor the epitaxial thin film.

並列關鍵字

thin film ； reflectance ； growth rate ； refractive index ； in situ monitor ； curve fitting

參考文獻

[1]. O. S. Heavens, Optical Properties of Thin Solid Films (Dover Publications, 1965).

[2]. F. L. McCrackin, E. Passaglia, R. R. Stromberg, and H. L. Steinberg, “Measurement of the thickness and refractive index of very thin films and the optical properties of surfaces by ellipsometry,” J. Res. Natl. Bur. Stand. 67A(4), 363－377 (1963).

[3]. Z. H. Lu, J. P. McCaffrey, B. Brar, G. D. Wilk, R. M. Wallace, L. C. Feldman, and S. P. Tay, “SiO2 film thickness metrology by x-ray photoelectron spectroscopy,” Appl. Phys. Lett. 71, 2764－2766 (1997).

[4]. A. M. Goodman, “Optical interference method for the approximate determination of refractive index and thickness of a transparent layer,” Appl. Opt. 17, 2779－2787 (1978).

[5]. E. Steinsland, T. Finstad, A. Ferber, and A. Haniieborg, “In situ measurement of etch rate of single crystal silicon,” in Solid-state Sensors and Actuators (IEEE, 1997), pp. 707－710.