서지주요정보
음향광학변조필터를 이용한 투명 박막의 입체 형상 측정 = Volumetric thickness profile measurements of transparent thin film with acousto-optic tunable filter
서명 / 저자 음향광학변조필터를 이용한 투명 박막의 입체 형상 측정 = Volumetric thickness profile measurements of transparent thin film with acousto-optic tunable filter / 김대석.
저자명 김대석 ; Kim, Dae-Suk
발행사항 [대전 : 한국과학기술원, 2002].
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등록번호

8013640

소장위치/청구기호

학술문화관(문화관) 보존서고

DME 02053

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초록정보

In recent years, the demand for measuring surface profiles of transparent thin films deposited on patterned structures has grown in various fields such as chemical mechanical planarization (CMP) and micro opto-electro-mechanical systems (MOEMS). So far, it was difficult to measure the film surface profile accurately by using non-destructive methods like optical measurement when a thin film is deposited on a patterned sample. The available and common methods for such measurements are destructive methods like scanning electron microscope (SEM) or mechanical stylus profilometer. However, although such destructive approaches can produce accurate measurements, they are undesirable due to long measurement times and destruction of samples. Thus, novel non-destructive methods for volumetric thickness profile measurement of a transparent film, thinner than the white light coherence length of 3~4 ㎛, that is deposited on a patterned sample is described in this thesis as an attempt to solve such shortcomings. The proposed AOTF based volumetric thickness profile measurement system consists of a visible acousto-optic tunable filter (AOTF) for wavelength scanning, a CCD sensor for 2-dimensional imaging, and a Michelson interferometer with a specially designed reference beam blocking mechanism. This thesis presents new three approaches for measuring the volumetric thickness profile as follows. The first one is peak detection method in the spectral domain. The key idea is to divide the measurement into two states using a beam blocking mechanism to separately obtain the two unknowns of thickness and surface profile. Such separate measurements are required to compensate for the phase change effect caused by the multi-reflected beams from the thin film. The final thin film volumetric thickness profile information is measured by obtaining the number of peaks and phase deviations from the two separately scanned spectral intensity values. The second is phase model fitting method with the capability of simultaneous volumetric thickness profile measurement. The thickness profile information is obtained through least square fitting with a phase model $Φ_m (k) = 2kh + ψ(k,d) + offset$, which has three unknowns of surface profile h, thickness d, and indeterminate initial phase offset. The accurate phase information in the spectral domain can be obtained by introducing a concept of spectral carrier frequency. Experimental results for a metal patterned sample shows that the thickness profile can be determined with an error range of around 10 nm. The third method called phase calculation method has fast and accurate volumetric thickness profile measurement capability. This method combines the benefits of the previously mentioned two methods. In this approach, the two phase information are obtained separately with the help of beam blocking plate. The first phase function compensates for the phase change effect caused by the multi-reflected beams from the thin film and the other is a total phase function for the interference between a reference mirror plane and the film deposited patterned sample. Compensation for the phase change effect was achieved by measuring the 3 dimensional film thickness information separately prior to surface profile measurement. Then the final thin film surface profile information was measured by using the total phase function which is obtained through spectral frequency domain signal processing. This total phase calculation algorithm is based on the newly proposed spectral carrier frequency concept.

서지기타정보

서지기타정보
청구기호 {DME 02053
형태사항 viii, 86 p. : 삽도 ; 26 cm
언어 한국어
일반주기 저자명의 영문표기 : Dae-Suk Kim
지도교수의 한글표기 : 김수현
공동교수의 한글표기 : 공홍진
지도교수의 영문표기 : Soo-Hyun Kim
공동교수의 영문표기 : Hong-Jin Kong
수록잡지명 : "Fast thickness profile measurement using AOTF(Acousto-Optic Tunable Filter) based peak detection method". Measurement science and technologh(Rapid communication), (2002)
학위논문 학위논문(박사) - 한국과학기술원 : 기계공학전공,
서지주기 참고문헌 : p. 81-86
주제 음향광학변조필터
입체형상
박막
분광영상
위상
AOTF
volumetric thickness profile
thin film
spectral imaging
phase
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