MOCVD晶圓表面溫度即時量測系統之開發

Development of in-situ measurement system of wafer surface temperature in MOCVD process

王俊程(Chun-Cheng Wang)

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(2015年)

摘要

本論文在開發一套晶圓表面溫度即時量測系統。應用於薄膜製程時，即時監控晶圓表面溫度，有效提高製程品質。根據普朗克黑體輻射理論與克希荷夫定理，以發射率修正量測溫度值。實驗以一道雷射光垂直入射晶圓表面，反射光與熱輻射由光偵測器接收，使用鎖相放大技術將熱輻射訊號與反射光訊號分離，並藉由一個標準參考片取得反射光強與反射率之關係、獲得晶圓反射率，再依據克希荷夫定理推算出發射率；透過軟體計算，將所得之熱輻射訊號求解溫度，並以發射率補償量測之溫度值。
本研究量測矽基板以及藍寶石基板於近紅外光940nm之熱輻射訊號。並使用相同波長之雷射二極體量測基板的發射率，藉以修正量測之溫度。溫度量測範圍約於450℃以上時，系統能較穩定地量測到溫度。於低溫段約450℃的系統解析度約為6℃；於高溫段700℃以上時，系統量測解析度皆在0.1℃以內。

關鍵字

光學高溫計 ； MOCVD ； 熱輻射 ； 反射率 ； 發射率 ； 即時量測

並列摘要

The purpose of this paper is to measure the wafer surface temperature during the Metal Organic Chemical Vapor Deposition (MOCVD) process. Measurement are based on Plank’s blackbody radiation theorem and Kirchhoff’s law. A function generator (FG) is used to modulate the laser diode (LD), so that the high-frequency modulated laser beam with a wavelength of 940 nm is normally incident on the wafer. The reflected laser beam and the thermal radiation from the wafer surface are received by a photo diode. Then, the total signals from the reflected laser light and thermal radiation are transmitted to a personal computer (PC) via a data acquisition card (DAQ). A lock-in amplifier is used to demodulate the amplitude of the reflected light signal, and particular algorithms are developed to compute the reflectance and the thermal radiation signal, and solve for the temperature. Moreover, the emissivity can be obtained from the reflectance based on Kirchhoff’s law, to compensate for the temperature.
The experimental results show that the resolution of the temperature at about 450℃ is 6℃, and the resolutions of temperature above 700℃ are within 0.1℃.

並列關鍵字

pyrometer ； MOCVD ； thermal radiation ； reflectance ； emissivity ； in-situ measurement

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