Vibration insensitive interferometry for multilayer thin-film thickness profile measurement

• Main Authors: GHIM YOUNG SIK, RHEE HYUG GYO, SEO YONG BUM
• Format: Patent
• Language: English; Korean
• Published: 02.09.2021
• Subjects: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS; MEASURING LENGTH, THICKNESS OR SIMILAR LINEARDIMENSIONS; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PHYSICS; TESTING

The present invention relates to an apparatus and method for measuring the thickness and profile of a multilayer thin film using vibration-insensitive interferometry, and more specifically, to an apparatus for measuring the thickness and profile of an object to be measured coated with multilayer thin film. The apparatus for measuring the thickness and profile of a multilayer thin film using vibration-insensitive interferometry is characterized by comprising: an illumination optical module having a light source for emitting light; a polarization beam splitter which reflects a first polarized wave of light emitted from the illumination optical module and allows a second polarized wave to be transmitted therethrough; a first quarter wave plate which converts the reflected light reflected by the object to be measured into a second polarized/reflected wave after the first polarized wave reflected by the polarization beam splitter passes therethrough; a second quarter wave plate which converts the reflected light reflected by a reference reflector into a first polarized/reflected wave after the second polarized wave reflected by the polarization beam splitter passes therethrough; a third quarter wave plate through which the second polarized/reflected wave that has passed through the polarization beam splitter and the first polarized/reflected wave reflected by the polarization beam splitter pass and which generates an interference signal by generating a phase delay between the second polarized/reflected wave and the first polarized/reflected wave; an imaging optical system to which the interference signal passes through the third quarter wave plate and is incident; a slit which allows only a selected line of the interference signal pattern that has passed through the imaging optical system to pass therethrough; an image spectrometer which convert a line interference signal that has passed through the slit into a spectral pattern; a polarization camera which acquires and measuring spectral images having different phase shift states; and an analysis means which measures and analyzes the profile of the object to be measured from the spectral images having the different phase shift states. In accordance with the present invention, the apparatus has the effect of measuring the reflectance of an object to be measured by acquiring a plurality of reflected signal images. 본 발명은 진동둔감 간섭법을 이용한 다층박막 두께 및 형상 측정장치 및 측정방법에 관한 것으로, 보다 상세하게는 다층 박막이 코팅된 측정대상물의 두께 및 형상을 측정하기 위한 장치에 있어서, 광을 출사시키는 광원을 갖는 조명광학모듈; 상기 조명광학모듈에서 출사된 광의 제1편광파를 반사시키고, 제2편광파를 투과시키는 편광빔스플리터; 상기 편광빔스플리터에 의해 반사된 제1편광파가 통과된 후, 상기 측정대상물에 반사된 반사광을 제2편광 반사파로 변환시키는 제1쿼터파장판; 상기 편광빔스플리터에 투과된 제2편광파가 통과된 후, 기준반사판에 반사된 반사광을 제1편광 반사파로 변환시키는 제2쿼터파장판; 상기 편광빔스플리터를 투과한 제2편광 반사파와, 상기 편광빔스플리터에 의해 반사된 제1편광 반사파가 통과되어 상기 제2편광 반사파와 상기 제1편광 반사파의 위상지연을 발생시켜 간섭신호를 생성하는 제3쿼터파장판; 상기 제3쿼터파장판을 통과한 후, 간섭신호가 입사되는 이미징 광학계; 상기 이미징 광학계를 통과한 간섭신호 패턴의 선택된 라인만을 투과시키는 슬릿; 상기 슬릿을 통과한 라인 간섭 신호를 분광 패턴으로 변환하는 영상분광기; 서로 다른 위상천이 상태를 갖는 분광 영상을 획득, 측정하는 편광카메라; 및 상기 서로 다른 위상천이 상태를 갖는 분광 영상으로부터 측정대상물의 형상을 측정, 분석하는 분석수단;을 포함하는 것을 특징으로 하는 진동둔감 간섭법을 이용한 다층박막 두께 및 형상 측정장치에 관한 것이다.