WO2023146085A1 - Optical inspection apparatus - Google Patents

Optical inspection apparatus Download PDF

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Publication number
WO2023146085A1
WO2023146085A1 PCT/KR2022/018270 KR2022018270W WO2023146085A1 WO 2023146085 A1 WO2023146085 A1 WO 2023146085A1 KR 2022018270 W KR2022018270 W KR 2022018270W WO 2023146085 A1 WO2023146085 A1 WO 2023146085A1
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Prior art keywords
optical system
illumination
light
detector
reflected light
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PCT/KR2022/018270
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French (fr)
Korean (ko)
Inventor
김상준
이성수
장주일
Original Assignee
주식회사 오로스 테크놀로지
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Publication of WO2023146085A1 publication Critical patent/WO2023146085A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/09—Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/28—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/30—Collimators

Definitions

  • the present invention relates to an optical inspection device, and more particularly, to an optical inspection device for finding a measurement region of a sample to be measured.
  • Spectroscopic ellipsometry is used as a method for deriving information such as thickness, refractive index (n), extinction coefficient (k), and optical bandgap of a semiconductor thin film.
  • SE Spectroscopic ellipsometry
  • Spectroscopic ellipsometry is an analysis method that investigates the optical properties of a material by using the property that the polarization state changes according to the refractive index or thickness of the medium after light incident on the material is reflected or transmitted through the surface.
  • a spectroscopic ellipsometer used in the semiconductor industry has a micro focal spot having a size of several tens of ⁇ m. To achieve this, an optical system using a transmissive or reflective optical element is configured.
  • a spectroscopic ellipsometer acquires a spectrum that provides only indirect information about the thickness or optical properties of a thin film constituting a sample as a measurement value, it cannot find a measurement location by itself. Therefore, a separate optical inspection device (navigation optical device) is required to guide the spectroscopic ellipsometer to the measurement location by finding the measurement location, the focal plane, the inclination of the sample, and the like.
  • the present invention is to respond to the above-mentioned needs, and an object of the present invention is to provide an optical inspection device having a new structure capable of finding a measurement position, a focal plane, and a tilt of a sample for other inspection devices such as a spectroscopic ellipsometer.
  • the present invention provides a first illumination optical system configured to irradiate a first illumination light to a measurement position on a sample surface, and configured to condense a first reflected light from the sample surface and form an image on a first detector.
  • an image acquisition unit having an imaging optical system;
  • a second illumination optical system configured to radiate a second illumination light to a measurement position on a sample surface, a beam shaping optical system configured to change a shape of a second reflected light from the sample surface, and the second reflected light passing through the beam shaping optical system forms an image.
  • an optical inspection device including a configured distance sensor.
  • the beam shaping optical system provides an optical inspection device configured to change the shape of the second reflected light to a circular shape when the distance between the objective lens and the sample surface is a reference distance, and to change it to an elliptical shape when the distance is different from the reference distance. do.
  • the beam shaping optical system provides an optical inspection device including a pair of cylinder lenses having power directions orthogonal to each other.
  • the second illumination optical system is an optical inspection device configured to condense a second illumination light at a measurement position on the sample surface and collect second reflected light reflected at the measurement position by using an objective lens of the first illumination optical system.
  • the reference distance provides an optical inspection device that is a distance at which the image acquiring unit is focused.
  • the second illumination light is an infrared ray
  • the optical inspection includes a hot mirror disposed between the first detector and the objective lens to prevent the second illumination light and the second reflected light from being incident on the first detector. provide the device.
  • the second detector provides an optical inspection device of a quad cell.
  • the second illumination light is a laser
  • the second beam splitter is a polarization beam splitter
  • a tilt detection unit including a third illumination optical system configured to radiate third illumination light to a measurement position on the sample surface, and a third detector into which the third reflected light from the sample surface is incident in a non-imaged state Further comprising An optical inspection device is provided.
  • the third illumination light provides an optical inspection device that is a circular light.
  • the optical inspection apparatus has the advantage of precisely measuring the distance to the sample surface using a beam shaping optical system.
  • the image acquisition unit and the distance sensor share optical elements such as an objective lens.
  • FIG. 1 is a conceptual diagram of an optical inspection device according to an embodiment of the present invention.
  • FIG. 2 is a diagram illustrating an example of the beam shaping optical system shown in FIG. 1 .
  • FIG 3 is a diagram illustrating a change in shape of second reflected light according to a distance between an objective lens and a surface of a sample.
  • FIG. 4 is a conceptual diagram of an optical inspection device according to another embodiment of the present invention.
  • an optical inspection device includes an image acquisition unit 100 and a distance detection unit 200 .
  • An optical inspection device may serve to guide other measuring devices such as a spectroscopic ellipsometer to a measuring position.
  • the image acquisition unit 100 is used to acquire an image of the surface of the sample (S).
  • the optical inspection device may check the location of the measurement area using the image acquired by the image acquiring unit 100 .
  • the image acquisition unit 100 includes a first illumination optical system 110 , an imaging optical system 120 and a first detector 130 .
  • the first illumination optical system 110 is configured to irradiate the first illumination light to the measurement position on the surface of the sample S.
  • the first illumination optical system 110 may include a first light source 111 , a first beam splitter 113 and an objective lens 115 .
  • a halogen lamp, a xenon lamp, or a light emitting diode may be used as the first light source 111 .
  • the first light source 111 generates first illumination light in the visible ray region.
  • the first beam splitter 113 serves to reflect a part of the first illumination light emitted from the first light source 111 and guide it toward the objective lens 115 . In addition, a part of the first reflected light collected by the objective lens 115 is transmitted.
  • the objective lens 115 serves to condense the beam reflected from the first beam splitter 113 to the measuring position of the sample S and collect the reflected beam at the measuring position.
  • the objective lens 115 is installed on a lens focus actuator 117.
  • the lens focus actuator 117 serves to adjust the distance between the objective lens 115 and the sample S so that the focal plane of the image acquisition unit 100 is located on the surface of the sample S.
  • the imaging optical system 120 serves to focus the first reflected light from the surface of the specimen S and form an image on the first detector 130 .
  • the imaging optical system 120 utilizes the objective lens 115 and the first beam splitter 113 of the first illumination optical system 110 . Further, a hot mirror 121 and a tube lens 123 are included. The tube lens 123 serves to condense the first reflected light transmitted through the first beam splitter 113 and the hot mirror 121 to the first detector 130 . The hot mirror 121 reflects ultraviolet rays and transmits visible rays. The hot mirror 121 prevents ultraviolet rays from entering the first detector 130 .
  • the first detector 130 may be a CCD or CMOS camera.
  • the image acquisition unit 100 acquires an image of the surface of the specimen S by using the electrical signal from the first detector 130 .
  • the distance detector 200 serves to measure the distance between the objective lens 115 and the surface of the sample S. By controlling the lens focus actuator 117 using the distance measured by the distance detector 200, the focal plane of the image acquisition unit 100 may be positioned on the surface of the sample S.
  • the distance sensor 200 includes a second illumination optical system 210 , a beam shaping optical system 220 , and a second detector 230 .
  • the second illumination optical system 210 serves to radiate the second illumination light to the measurement position on the surface of the sample S.
  • the second illumination optical system 210 includes a second light source 211, a collimator 212 (collimation lens) that makes beams from the second light source 211 parallel, and a second beam splitter 213. Including, the hot mirror 121 of the image acquisition unit 100, the first beam splitter 113 and the objective lens 115 are also used.
  • a laser diode or light emitting diode may be used as the second light source 211 .
  • the second light source 211 generates second illumination light in the infrared region.
  • the second illumination light is reflected from the hot mirror 121 after passing through the second beam splitter 213 .
  • a laser it is preferable to use a polarization beam splitter as the second beam splitter 213 . This is because it is possible to minimize the decrease in the amount of light in the process of reflection and transmission.
  • the second illumination light reflected from the hot mirror 121 is incident on the objective lens 115 after passing through the first beam splitter 113 .
  • the objective lens 115 serves to condense the second illumination light onto the measuring position on the surface of the specimen S and collects the second reflected light reflected from the measuring position.
  • the present invention has an advantage of condensing the first illumination light and the second illumination light by using one objective lens 115 and collecting the first reflected light and the second reflected light.
  • infrared light having a different wavelength band from the first illumination light is used as the second illumination light, and the second reflection light and the first reflection light are separated using the hot mirror 121, and the light is transmitted to the first detector 130. The second reflected light is prevented from being incident.
  • the second reflected light collected by the objective lens 115 is reflected by the hot mirror 121 after passing through the first beam splitter 113 again. Since infrared rays cannot pass through the hot mirror 121 , the second reflected light in the infrared region does not enter the first detector 130 .
  • the second reflected light reflected from the hot mirror 121 is reflected from the second beam splitter 213 toward the second detector 230 .
  • the beam shaping optical system 220 is disposed between the second beam splitter 213 and the second detector 230 .
  • the beam shaping optical system 220 serves to change the shape of the second reflected light.
  • the second reflected light may be changed into a circular shape or an elliptical shape.
  • the beam shaping optical system 220 is configured to change the shape of the second reflected light to a circular shape when the distance between the objective lens 115 and the surface of the sample S is the reference distance, and to change it to an elliptical shape when the distance is different from the reference distance.
  • the reference distance is a distance at which the focal plane of the image acquisition unit 100 is placed on the surface of the specimen S.
  • FIG. 2 is a diagram illustrating an example of the beam shaping optical system shown in FIG. 1 .
  • the beam shaping optical system 220 may include a pair of cylinder lenses 221 and 223 whose power directions (PDs) are orthogonal to each other.
  • PDs power directions
  • cylinder lenses 221 and 223 having various shapes such as a rectangle, a square, a circle, and an ellipse may be used.
  • the cylinder lenses 221 and 223 are lenses that focus light on a line rather than a point.
  • the power direction refers to the curved reflection of the cylinder lenses 221 and 223, which have optical power.
  • a non-power direction (NPD) orthogonal to the power direction does not affect the optical power.
  • the focal lengths of the pair of cylinder lenses 221 and 223 may be the same or different.
  • a spherical lens or an aspheric lens may be used as the beam shaping optical system 220, it is preferable to use a pair of cylinder lenses 221 and 223 in that a shape change of the second reflected light can be maximized.
  • the second reflected light passing through the beam shaping optical system 220 is incident to the second detector 230 without being formed. That is, a lens for forming an image is not disposed between the beam shaping optical system 220 and the second detector 230 .
  • the second detector 230 may be a quad cell having four photodiodes, a CCD, a CMOS camera, or the like. In the case of using a quad cell, it can be confirmed that the focal plane of the image acquisition unit 100 is located on the surface of the sample when the magnitudes of electrical signals output from the four photodiodes are the same.
  • FIG. 3 is a diagram illustrating a change in shape of second reflected light according to a distance between an objective lens and a surface of a sample. As shown in (a) of FIG. 3, it is circular at the reference distance, and as shown in (b), when it is farther than the reference distance, the long axis is deformed into an ellipse tilted by -45 degrees, and shown in (c) As shown, when close, it deforms into an ellipse whose long axis is tilted at +45 degrees.
  • the image acquisition unit 100 may be located on the surface of the sample (S). If the second reflected light is an ellipse whose long axis is tilted by -45 degrees, the objective lens 115 is moved close to the surface of the sample (S), and if the second reflected light is an ellipse whose long axis is tilted by +45 degrees, the objective lens 115 ) may be moved away from the surface of the sample S so that the second reflected light has a circular shape.
  • the beam shaping optical system 220 may change the second reflection light into a circular ring or an elliptical ring.
  • the second illumination light may be formed in a ring shape.
  • FIG. 4 is a conceptual diagram of an optical inspection device according to another embodiment of the present invention. Since the embodiment shown in FIG. 4 is different from the embodiment shown in FIG. 1 in that it further includes the tilt sensor 300, only this will be described in detail.
  • the tilt sensor 300 includes a third illumination optical system 310 and a third detector 320 .
  • the inclination detection unit 300 inspects whether the surface of the specimen S is inclined.
  • the third illumination optical system 310 serves to irradiate the third illumination light to the measurement position on the surface of the sample S.
  • the third illumination optical system 310 includes a third light source 311, a collimator 312 that makes beams from the third light source 311 parallel, a third beam splitter 313, and a fourth beam.
  • a splitter 315 is included, and the hot mirror 121, the first beam splitter 113, and the objective lens 115 of the image acquisition unit 100 are also used as part of the third illumination optical system 310.
  • a laser diode or a light emitting diode may be used as the third light source 311 .
  • the third light source 311 generates third illumination light in the infrared region.
  • the third illumination light is preferably a circular light.
  • the third illumination light is reflected by the fourth beam splitter 315 after passing through the third beam splitter 313 . Then, it is reflected again at the hot mirror 121.
  • polarization beam splitters as the third beam splitter 313 and the fourth beam splitter 315 . This is because it is possible to minimize the decrease in the amount of light in the process of reflection and transmission.
  • the third illumination light reflected from the hot mirror 121 is incident on the objective lens 115 after passing through the first beam splitter 113 .
  • the objective lens 115 serves to condense the third illumination light onto the measuring position on the surface of the sample S and collect the third reflected light reflected from the measuring position.
  • This embodiment has the advantage of condensing the first illumination light, the second illumination light, and the third illumination light by using one objective lens 115 and collecting the first reflection light, the second reflection light, and the third illumination light.
  • infrared rays different from the first illumination light are used as the third illumination light
  • the third reflection light is separated from the first reflection light using the hot mirror 121
  • the third reflection light is reflected to the first detector 130. Prevent light from entering.
  • the third reflected light collected by the objective lens 114 is reflected by the hot mirror 121 after passing through the first beam splitter 113 again. Since infrared rays cannot pass through the hot mirror 121 , the third reflected light in the infrared region does not enter the first detector 130 .
  • the third reflected light reflected from the hot mirror 121 is reflected toward the third detector 320 from the fourth beam splitter 315 . And, after passing through the third beam splitter 313, it is incident on the third detector 320.
  • the third reflected light is incident to the third detector 320 without forming an image. That is, a lens for forming an image is not disposed between the third beam splitter 313 and the third detector 320 .
  • the third detector 320 may be a quad cell having four photodiodes, a CCD, a CMOS camera, or the like.
  • the tilt detection unit 300 inspects whether the surface of the sample S is tilted based on the degree to which the center of the reflected light incident on the third detector 320 deviates from the center of the third detector 320 . If the center of the third reflected light coincides with the center of the third detector 320, it is determined that the surface of the sample is not tilted, and the degree and direction of the tilt of the surface of the sample can be known through the degree and direction out of the center.

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Abstract

The present invention relates to an optical inspection apparatus and, more specifically, to an optical inspection apparatus for finding a measurement region of a sample to be measured. The present invention provides the optical inspection apparatus comprising: an image acquisition unit including a first illumination optical system, which emits first illumination light at a measurement position on the surface of a sample, and an imaging optical system, which concentrates first reflected light from the surface of the sample so as to form an image on a first detector; and a distance detection unit including a second illumination optical system, which emits second illumination light at the measurement position on the surface of the sample, a beam shaping optical system, which changes the shape of second reflected light from the surface of the sample, and a second detector on which the second reflected light having passed through the beam shaping optical system is incident in a state in which no image is formed, wherein the beam shaping optical system allows the shape of the second reflected light having passed through the beam shaping optical system to change according to the distance between the objective lens of the first illumination optical system and the surface of the sample.

Description

광학 검사 장치optical inspection device
본 발명은 광학 검사 장치에 관한 것으로서, 더욱 상세하게는 측정 대상 시료의 측정 영역을 찾기 위한 광학 검사 장치에 관한 것이다.The present invention relates to an optical inspection device, and more particularly, to an optical inspection device for finding a measurement region of a sample to be measured.
반도체 박막의 두께 및 굴절률(refractive index, n), 소광계수(extinction coefficient, k), 광학적 밴드갭(optical bandgap) 등의 정보를 도출하기 위한 방법으로서 분광 타원법(spectroscopic ellipsometry, SE)이 사용된다. 분광 타원법은 물질에 입사된 빛이 표면에서 반사 또는 투과 후, 그 매질의 굴절률이나 두께에 따라 편광 상태가 변화하는 성질을 이용하여 물질의 광학적인 특성을 조사하는 분석법이다.Spectroscopic ellipsometry (SE) is used as a method for deriving information such as thickness, refractive index (n), extinction coefficient (k), and optical bandgap of a semiconductor thin film. . Spectroscopic ellipsometry is an analysis method that investigates the optical properties of a material by using the property that the polarization state changes according to the refractive index or thickness of the medium after light incident on the material is reflected or transmitted through the surface.
반도체 산업 분야에서 사용되는 분광 타원계(spectroscopic ellipsometer)는 수십 ㎛의 크기를 갖는 미세 초점(micro focal spot)을 갖고 있는데, 이를 이루기 위해 투과형 혹은 반사형 광학 소자를 이용한 광학계를 구성하게 된다.A spectroscopic ellipsometer used in the semiconductor industry has a micro focal spot having a size of several tens of μm. To achieve this, an optical system using a transmissive or reflective optical element is configured.
그런데 이러한 분광 타원계는 시료를 구성하는 박막의 두께나 광학적 물성에 대한 간접적인 정보만을 제공하는 스펙트럼을 측정값으로 획득하기 때문에 스스로 측정 위치 등을 찾을 수 없다. 따라서 측정 위치, 초점면, 시료의 기울기 등을 찾아서 분광 타원계를 측정 위치로 안내하기 위한 별도의 광학 검사 장치(네비게이션 광학 장치)가 필요하다.However, since such a spectroscopic ellipsometer acquires a spectrum that provides only indirect information about the thickness or optical properties of a thin film constituting a sample as a measurement value, it cannot find a measurement location by itself. Therefore, a separate optical inspection device (navigation optical device) is required to guide the spectroscopic ellipsometer to the measurement location by finding the measurement location, the focal plane, the inclination of the sample, and the like.
본 발명은 상술한 요구에 대응하기 위한 것으로서, 분광 타원계 등의 다른 검사 장치를 위해 측정 위치, 초점면, 시료의 기울기를 찾을 수 있는 새로운 구조의 광학 검사 장치를 제공하는 것을 목적으로 한다.SUMMARY OF THE INVENTION The present invention is to respond to the above-mentioned needs, and an object of the present invention is to provide an optical inspection device having a new structure capable of finding a measurement position, a focal plane, and a tilt of a sample for other inspection devices such as a spectroscopic ellipsometer.
상술한 목적을 달성하기 위해서, 본 발명은 제1 조명 광을 시료 표면의 측정위치에 조사하도록 구성된 제1 조명 광학계와, 상기 시료 표면으로부터의 제1 반사광을 집광하여 제1 검출기에 결상시키도록 구성된 결상 광학계를 구비하는 이미지 획득부와; 제2 조명 광을 시료 표면의 측정위치에 조사하도록 구성된 제2 조명 광학계와, 상기 시료 표면으로부터의 제2 반사광의 형태를 변경하는 빔 쉐이핑 광학계와, 상기 빔 쉐이핑 광학계를 통과한 제2 반사광이 결상되지 않은 상태로 입사되는 제2 검출기를 구비하며, 상기 빔 쉐이핑 광학계는 상기 제1 조명 광학계의 대물렌즈와 상기 시료 표면 사이의 거리에 따라서 상기 빔 쉐이핑 광학계를 통과한 제2 반사광의 형태가 변화하도록 구성된 거리 감지부를 포함하는 광학 검사 장치를 제공한다.In order to achieve the above object, the present invention provides a first illumination optical system configured to irradiate a first illumination light to a measurement position on a sample surface, and configured to condense a first reflected light from the sample surface and form an image on a first detector. an image acquisition unit having an imaging optical system; A second illumination optical system configured to radiate a second illumination light to a measurement position on a sample surface, a beam shaping optical system configured to change a shape of a second reflected light from the sample surface, and the second reflected light passing through the beam shaping optical system forms an image. and a second detector that is incident without being incident, and the beam shaping optical system changes the shape of the second reflected light passing through the beam shaping optical system according to the distance between the object lens of the first illumination optical system and the sample surface. Provided is an optical inspection device including a configured distance sensor.
또한, 상기 빔 쉐이핑 광학계는 상기 대물렌즈와 상기 시료 표면 사이의 거리가 기준 거리일 경우에는 제2 반사광의 형태를 원형으로 변경하고, 기준 거리와 다를 경우에는 타원형으로 변경하도록 구성된 광학 검사 장치를 제공한다.In addition, the beam shaping optical system provides an optical inspection device configured to change the shape of the second reflected light to a circular shape when the distance between the objective lens and the sample surface is a reference distance, and to change it to an elliptical shape when the distance is different from the reference distance. do.
또한, 상기 빔 쉐이핑 광학계는 파워 방향(power direction)이 서로 직교하는 한 쌍의 실린더 렌즈를 포함하는 광학 검사 장치를 제공한다.In addition, the beam shaping optical system provides an optical inspection device including a pair of cylinder lenses having power directions orthogonal to each other.
또한, 상기 제2 조명 광학계는 상기 제1 조명 광학계의 대물렌즈를 사용하여, 상기 시료 표면의 측정위치에 제2 조명 광을 집광시키고 상기 측정위치에서 반사된 제2 반사광을 수집하도록 구성된 광학 검사 장치를 제공한다.In addition, the second illumination optical system is an optical inspection device configured to condense a second illumination light at a measurement position on the sample surface and collect second reflected light reflected at the measurement position by using an objective lens of the first illumination optical system. provides
또한, 상기 기준 거리는 상기 이미지 획득부의 초점이 맞는 거리인 광학 검사 장치를 제공한다.In addition, the reference distance provides an optical inspection device that is a distance at which the image acquiring unit is focused.
또한, 상기 제2 조명광은 적외선이며, 상기 제1 검출기에 상기 제2 조명광 및 상기 제2 반사광이 입사하는 것을 방지하도록 상기 제1 검출기와, 상기 대물렌즈 사이에 배치되는 핫 미러를 포함하는 광학 검사 장치를 제공한다.In addition, the second illumination light is an infrared ray, and the optical inspection includes a hot mirror disposed between the first detector and the objective lens to prevent the second illumination light and the second reflected light from being incident on the first detector. provide the device.
또한, 상기 제2 검출기는 쿼드 셀(quad cell)인 광학 검사 장치를 제공한다.In addition, the second detector provides an optical inspection device of a quad cell.
또한, 상기 제2 조명 광은 레이저이며, 상기 제2 빔 스플리터는 편광 빔 스플리터인 광학 검사 장치를 제공한다.In addition, the second illumination light is a laser, and the second beam splitter is a polarization beam splitter.
또한, 제3 조명 광을 시료 표면의 측정위치에 조사하도록 구성된 제3 조명 광학계와, 상기 시료 표면으로부터의 제3 반사광이 결상되지 않은 상태로 입사되는 제3 검출기를 포함하는 경사 감지부를 더 포함하는 광학 검사 장치를 제공한다.In addition, a tilt detection unit including a third illumination optical system configured to radiate third illumination light to a measurement position on the sample surface, and a third detector into which the third reflected light from the sample surface is incident in a non-imaged state Further comprising An optical inspection device is provided.
또한, 상기 제3 조명 광은 원형 광인 광학 검사 장치를 제공한다.In addition, the third illumination light provides an optical inspection device that is a circular light.
본 발명에 따른 광학 검사 장치는 빔 쉐이핑 광학계를 이용하여 시료 표면과의 거리를 정밀하게 측정할 수 있다는 장점이 있다. 또한, 이미지 획득부와 거리 감지부가 대물렌즈 등의 광학 요소들을 공유한다는 장점이 있다.The optical inspection apparatus according to the present invention has the advantage of precisely measuring the distance to the sample surface using a beam shaping optical system. In addition, there is an advantage in that the image acquisition unit and the distance sensor share optical elements such as an objective lens.
도 1은 본 발명의 일실시예에 따른 광학 검사 장치의 개념도이다.1 is a conceptual diagram of an optical inspection device according to an embodiment of the present invention.
도 2는 도 1에 도시된 빔 쉐이핑 광학계의 일 예를 나타낸 도면이다.FIG. 2 is a diagram illustrating an example of the beam shaping optical system shown in FIG. 1 .
도 3은 대물렌즈와 시료 표면 사이의 거리에 따른 제2 반사광의 형태변화를 나타낸 도면이다.3 is a diagram illustrating a change in shape of second reflected light according to a distance between an objective lens and a surface of a sample.
도 4는 본 발명의 다른 실시예에 따른 광학 검사 장치의 개념도이다.4 is a conceptual diagram of an optical inspection device according to another embodiment of the present invention.
이하, 첨부된 도면들을 참고하여 본 발명의 일실시예들을 상세히 설명하기로 한다. 그러나 본 발명의 실시예는 여러 가지 다른 형태들로 변형될 수 있으며, 본 발명의 범위가 아래에서 상술하는 실시예들로 한정되는 것으로 해석되어서는 안 된다. 본 발명의 실시예들은 당업계에서 평균적인 지식을 가진 자에게 본 발명을 보다 완전하게 설명하기 위하여 제공되는 것이다. 따라서 도면에서의 요소의 형상 등은 더욱 명확한 설명을 강조하기 위해서 과장된 것이며, 도면상에서 동일한 부호로 표시된 요소는 동일한 요소를 의미한다.Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings. However, embodiments of the present invention may be modified in many different forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. Embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. Therefore, the shapes of elements in the drawings are exaggerated to emphasize more clear description, and elements indicated by the same reference numerals in the drawings mean the same elements.
도 1에 도시된 바와 같이, 본 발명의 일실시예에 따른 광학 검사 장치는 이미지 획득부(100)와, 거리 감지부(200)를 포함한다. 본 발명의 일실시예에 따른 광학 검사 장치는 분광 타원계 등의 다른 측정 장치를 측정 위치로 안내하는 역할을 할 수 있다.As shown in FIG. 1 , an optical inspection device according to an embodiment of the present invention includes an image acquisition unit 100 and a distance detection unit 200 . An optical inspection device according to an embodiment of the present invention may serve to guide other measuring devices such as a spectroscopic ellipsometer to a measuring position.
이미지 획득부(100)는 시료(S) 표면의 이미지 획득에 사용된다. 광학 검사 장치는 이미지 획득부(100)에서 획득된 이미지를 이용하여 측정 영역의 위치를 확인할 수 있다.The image acquisition unit 100 is used to acquire an image of the surface of the sample (S). The optical inspection device may check the location of the measurement area using the image acquired by the image acquiring unit 100 .
이미지 획득부(100)는 제1 조명 광학계(110), 결상 광학계(120) 및 제1 검출기(130)를 구비한다.The image acquisition unit 100 includes a first illumination optical system 110 , an imaging optical system 120 and a first detector 130 .
제1 조명 광학계(110)는 제1 조명 광을 시료(S) 표면의 측정위치에 조사하도록 구성된다. 제1 조명 광학계(110)는 제1 광원(111), 제1 빔 스플리터(113) 및 대물렌즈(115)를 포함할 수 있다. The first illumination optical system 110 is configured to irradiate the first illumination light to the measurement position on the surface of the sample S. The first illumination optical system 110 may include a first light source 111 , a first beam splitter 113 and an objective lens 115 .
제1 광원(111)으로는 할로겐 램프, 제논 램프, 발광다이오드 등을 사용할 수 있다. 제1 광원(111)은 가시광선 영역의 제1 조명 광을 생성한다.A halogen lamp, a xenon lamp, or a light emitting diode may be used as the first light source 111 . The first light source 111 generates first illumination light in the visible ray region.
제1 빔 스플리터(113)는 제1 광원(111)으로부터 나온 제1 조명 광의 일부를 반사시켜 대물렌즈(115) 측으로 안내하는 역할을 한다. 또한, 대물렌즈(115)에서 수집한 제1 반사 광의 일부를 투과시킨다.The first beam splitter 113 serves to reflect a part of the first illumination light emitted from the first light source 111 and guide it toward the objective lens 115 . In addition, a part of the first reflected light collected by the objective lens 115 is transmitted.
대물렌즈(115)는 제1 빔 스플리터(113)에서 반사된 빔을 시료(S)의 측정위치에 집광시키고, 측정위치에서의 반사된 빔을 수집하는 역할을 한다. 대물렌즈(115)는 렌즈 초점 액추에이터(lens focus actuator, 117)에 설치된다.The objective lens 115 serves to condense the beam reflected from the first beam splitter 113 to the measuring position of the sample S and collect the reflected beam at the measuring position. The objective lens 115 is installed on a lens focus actuator 117.
렌즈 초점 액추에이터(117)는 대물렌즈(115)와 시료(S) 사이의 거리를 조절하여 이미지 획득부(100)의 초점면이 시료(S)의 표면에 위치하도록 조절하는 역할을 한다.The lens focus actuator 117 serves to adjust the distance between the objective lens 115 and the sample S so that the focal plane of the image acquisition unit 100 is located on the surface of the sample S.
결상 광학계(120)는 시료(S) 표면으로부터의 제1 반사광을 집광하여 제1 검출기(130)에 결상시키는 역할을 한다.The imaging optical system 120 serves to focus the first reflected light from the surface of the specimen S and form an image on the first detector 130 .
결상 광학계(120)는 제1 조명 광학계(110)의 대물렌즈(115)와 제1 빔 스플리터(113)를 활용한다. 그리고 핫 미러(121, hot mirror)와 튜브 렌즈(123)를 더 포함한다. 튜브 렌즈(123)는 제1 빔 스플리터(113)와 핫 미러(121)를 투과한 제1 반사광을 제1 검출기(130)에 집광하는 역할을 한다. 핫 미러(121)는 자외선을 반사하고, 가시광선을 투과시킨다. 핫 미러(121)는 제1 검출기(130)에 자외선이 입사하는 것을 방지한다.The imaging optical system 120 utilizes the objective lens 115 and the first beam splitter 113 of the first illumination optical system 110 . Further, a hot mirror 121 and a tube lens 123 are included. The tube lens 123 serves to condense the first reflected light transmitted through the first beam splitter 113 and the hot mirror 121 to the first detector 130 . The hot mirror 121 reflects ultraviolet rays and transmits visible rays. The hot mirror 121 prevents ultraviolet rays from entering the first detector 130 .
제1 검출기(130)는 CCD나 CMOS 카메라일 수 있다. 이미지 획득부(100)는 제1 검출기(130)로부터의 전기신호를 이용하여, 시료(S) 표면의 이미지를 획득한다.The first detector 130 may be a CCD or CMOS camera. The image acquisition unit 100 acquires an image of the surface of the specimen S by using the electrical signal from the first detector 130 .
거리 감지부(200)는 대물렌즈(115)와 시료(S) 표면 사이의 거리를 측정하는 역할을 한다. 거리 감지부(200)에서 측정된 거리를 이용하여 렌즈 초점 액추에이터(117)를 제어하면, 이미지 획득부(100)의 초점면을 시료(S) 표면에 위치시킬 수 있다.The distance detector 200 serves to measure the distance between the objective lens 115 and the surface of the sample S. By controlling the lens focus actuator 117 using the distance measured by the distance detector 200, the focal plane of the image acquisition unit 100 may be positioned on the surface of the sample S.
거리 감지부(200)는 제2 조명 광학계(210)와, 빔 쉐이핑 광학계(220)와, 제2 검출기(230)를 포함한다.The distance sensor 200 includes a second illumination optical system 210 , a beam shaping optical system 220 , and a second detector 230 .
제2 조명 광학계(210)는 제2 조명 광을 시료(S) 표면의 측정위치에 조사하는 역할을 한다. 본 실시예에서 제2 조명 광학계(210)는 제2 광원(211)과, 제2 광원(211)으로부터의 빔을 평행으로 만드는 시준기(212, collimation lens)와, 제2 빔 스플리터(213)를 포함하며, 이미지 획득부(100)의 핫 미러(121), 제1 빔 스플리터(113) 및 대물렌즈(115)도 사용한다.The second illumination optical system 210 serves to radiate the second illumination light to the measurement position on the surface of the sample S. In this embodiment, the second illumination optical system 210 includes a second light source 211, a collimator 212 (collimation lens) that makes beams from the second light source 211 parallel, and a second beam splitter 213. Including, the hot mirror 121 of the image acquisition unit 100, the first beam splitter 113 and the objective lens 115 are also used.
제2 광원(211)으로는 레이저 다이오드 또는 발광다이오드를 사용할 수 있다. 제2 광원(211)은 적외선 영역의 제2 조명 광을 생성한다. 제2 조명 광은 제2 빔 스플리터(213)를 투과한 후 핫 미러(121)에서 반사된다. 제2 조명 광으로 레이저를 사용하는 경우에는 제2 빔 스플리터(213)로 편광 빔 스플리터를 사용하는 것이 바람직하다. 반사 및 투과 과정에서 광량이 줄어드는 것을 최소화할 수 있기 때문이다.A laser diode or light emitting diode may be used as the second light source 211 . The second light source 211 generates second illumination light in the infrared region. The second illumination light is reflected from the hot mirror 121 after passing through the second beam splitter 213 . When a laser is used as the second illumination light, it is preferable to use a polarization beam splitter as the second beam splitter 213 . This is because it is possible to minimize the decrease in the amount of light in the process of reflection and transmission.
그리고 핫 미러(121)에서 반사된 제2 조명 광은 제1 빔 스플리터(113)를 투과한 후 대물렌즈(115)에 입사한다. 대물렌즈(115)는 제2 조명 광을 시료(S) 표면의 측정위치에 집광시키고, 측정위치에서의 반사된 제2 반사광을 수집하는 역할을 한다. 본 발명은 하나의 대물렌즈(115)를 이용하여 제1 조명 광과 제2 조명 광을 집광시키고, 제1 반사 광과 제2 반사 광을 수집한다는 장점이 있다.The second illumination light reflected from the hot mirror 121 is incident on the objective lens 115 after passing through the first beam splitter 113 . The objective lens 115 serves to condense the second illumination light onto the measuring position on the surface of the specimen S and collects the second reflected light reflected from the measuring position. The present invention has an advantage of condensing the first illumination light and the second illumination light by using one objective lens 115 and collecting the first reflected light and the second reflected light.
본 발명에서는 제2 조명 광으로 제1 조명 광과 파장 대역이 다른 적외선을 사용하고, 핫 미러(121)를 사용하여 제2 반사 광과 제1 반사 광을 분리하여, 제1 검출기(130)로 제2 반사 광이 입사하는 것을 방지한다.In the present invention, infrared light having a different wavelength band from the first illumination light is used as the second illumination light, and the second reflection light and the first reflection light are separated using the hot mirror 121, and the light is transmitted to the first detector 130. The second reflected light is prevented from being incident.
대물렌즈(115)에서 수집된 제2 반사광은 다시 제1 빔 스플리터(113)를 투과한 후에 핫 미러(121)에서 반사된다. 적외선은 핫 미러(121)를 투과하지 못하므로, 적외선 영역의 제2 반사광이 제1 검출기(130)로 입사하지 않는다.The second reflected light collected by the objective lens 115 is reflected by the hot mirror 121 after passing through the first beam splitter 113 again. Since infrared rays cannot pass through the hot mirror 121 , the second reflected light in the infrared region does not enter the first detector 130 .
핫 미러(121)에서 반사된 제2 반사광은 제2 빔 스플리터(213)에서 제2 검출기(230) 쪽으로 반사된다.The second reflected light reflected from the hot mirror 121 is reflected from the second beam splitter 213 toward the second detector 230 .
빔 쉐이핑 광학계(220)는 제2 빔 스플리터(213)와 제2 검출기(230) 사이에 배치된다. 빔 쉐이핑 광학계(220)는 제2 반사광의 형태를 변경시키는 역할을 한다. 예를 들어, 제2 반사광을 원형 또는 타원형으로 변경시킬 수 있다. 빔 쉐이핑 광학계(220)는 대물렌즈(115)와 시료(S) 표면 사이의 거리가 기준 거리일 경우에는 제2 반사광의 형태를 원형으로 변경하고, 기준 거리와 다를 경우에는 타원형으로 변경하도록 구성될 수 있다. 기준 거리는 이미지 획득부(100)의 초점면이 시료(S) 표면에 놓이는 거리이다.The beam shaping optical system 220 is disposed between the second beam splitter 213 and the second detector 230 . The beam shaping optical system 220 serves to change the shape of the second reflected light. For example, the second reflected light may be changed into a circular shape or an elliptical shape. The beam shaping optical system 220 is configured to change the shape of the second reflected light to a circular shape when the distance between the objective lens 115 and the surface of the sample S is the reference distance, and to change it to an elliptical shape when the distance is different from the reference distance. can The reference distance is a distance at which the focal plane of the image acquisition unit 100 is placed on the surface of the specimen S.
도 2는 도 1에 도시된 빔 쉐이핑 광학계의 일 예를 나타낸 도면이다. 도 2에 도시된 바와 같이, 빔 쉐이핑 광학계(220)는 파워 방향(power direction, PD)이 서로 직교하는 한 쌍의 실린더 렌즈(221, 223)를 포함할 수 있다. 실린더 렌즈(221, 223)로는 직사각형, 정사각형, 원형, 타원형 등 다양한 외형의 실린더 렌즈(221, 223)를 사용할 수 있다. 실린더 렌즈(221, 223)는 점이 아닌 선에 빛의 초점을 맞춘 렌즈이다. 파워 방향은 광학적 파워를 가지고 있는, 실린더 렌즈(221, 223)의 만곡된 반향을 의미한다. 파워 방향과 직교하는 논-파워 방향(non-power direction, NPD)은 광학적 파워에 영향을 주지 않는다. 한 쌍의 실린더 렌즈(221, 223)의 초점 거리는 서로 같을 수도 있으며, 서로 다를 수도 있다.FIG. 2 is a diagram illustrating an example of the beam shaping optical system shown in FIG. 1 . As shown in FIG. 2 , the beam shaping optical system 220 may include a pair of cylinder lenses 221 and 223 whose power directions (PDs) are orthogonal to each other. As the cylinder lenses 221 and 223 , cylinder lenses 221 and 223 having various shapes such as a rectangle, a square, a circle, and an ellipse may be used. The cylinder lenses 221 and 223 are lenses that focus light on a line rather than a point. The power direction refers to the curved reflection of the cylinder lenses 221 and 223, which have optical power. A non-power direction (NPD) orthogonal to the power direction does not affect the optical power. The focal lengths of the pair of cylinder lenses 221 and 223 may be the same or different.
빔 쉐이핑 광학계(220)로 구면 렌즈나 비구면 렌즈를 사용할 수도 있으나, 제2 반사광의 형태 변화를 극대화할 수 있다는 점에서 한 쌍의 실린더 렌즈(221, 223)를 사용하는 것이 바람직하다.Although a spherical lens or an aspheric lens may be used as the beam shaping optical system 220, it is preferable to use a pair of cylinder lenses 221 and 223 in that a shape change of the second reflected light can be maximized.
제2 검출기(230)에는 빔 쉐이핑 광학계(220)를 통과한 제2 반사광이 결상되지 않은 상태로 입사된다. 즉, 빔 쉐이핑 광학계(220)와 제2 검출기(230) 사이에는 결상을 위한 렌즈가 배치되지 않는다. 제2 검출기(230)는 4개의 광 다이오드를 구비하는 쿼드 셀, CCD, CMOS 카메라 등일 수 있다. 쿼드 셀을 사용하는 경우에는 4개의 광 다이오드에서 출력되는 전기신호의 크기가 같아지면 이미지 획득부(100)의 초점면이 시료의 표면에 위치하는 것으로 확인할 수 있다.The second reflected light passing through the beam shaping optical system 220 is incident to the second detector 230 without being formed. That is, a lens for forming an image is not disposed between the beam shaping optical system 220 and the second detector 230 . The second detector 230 may be a quad cell having four photodiodes, a CCD, a CMOS camera, or the like. In the case of using a quad cell, it can be confirmed that the focal plane of the image acquisition unit 100 is located on the surface of the sample when the magnitudes of electrical signals output from the four photodiodes are the same.
도 3은 대물렌즈와 시료 표면 사이의 거리에 따른 제2 반사광의 형태변화를 나타낸 도면이다. 도 3의 (a)에 도시된 바와 같이, 기준 거리일 때에는 원형이며, (b)에 도시된 바와 같이, 기준 거리에 비해서 멀면 장축이 -45도 기울어진 타원형으로 변형되며, (c)에 도시된 바와 같이, 가까우면 장축이 +45도 기울어진 타원형으로 변형된다.3 is a diagram illustrating a change in shape of second reflected light according to a distance between an objective lens and a surface of a sample. As shown in (a) of FIG. 3, it is circular at the reference distance, and as shown in (b), when it is farther than the reference distance, the long axis is deformed into an ellipse tilted by -45 degrees, and shown in (c) As shown, when close, it deforms into an ellipse whose long axis is tilted at +45 degrees.
따라서 제2 검출기(230)에서 확인되는 제2 반사광이 원형이 될 때까지 렌즈 초점 액추에이터(117)를 이용하여 대물렌즈(115)와 시료(S) 표면 사이의 거리를 조절하면 이미지 획득부(100)의 초점면이 시료(S) 표면에 위치하도록 할 수 있다. 만약, 제2 반사광이 장축이 -45도 기울어진 타원형이면, 대물렌즈(115)를 시료(S) 표면에 가깝게 이동시키고, 제2 반사광이 장축이 +45도 기울어진 타원형이면, 대물렌즈(115)를 시료(S) 표면으로부터 멀어지게 이동시켜 제2 반사광이 원형이 되도록 할 수 있다.Therefore, if the distance between the objective lens 115 and the surface of the sample S is adjusted using the lens focus actuator 117 until the second reflected light identified by the second detector 230 becomes circular, the image acquisition unit 100 ) may be located on the surface of the sample (S). If the second reflected light is an ellipse whose long axis is tilted by -45 degrees, the objective lens 115 is moved close to the surface of the sample (S), and if the second reflected light is an ellipse whose long axis is tilted by +45 degrees, the objective lens 115 ) may be moved away from the surface of the sample S so that the second reflected light has a circular shape.
만약, 제2 조명 광이 링 형태라면, 빔 쉐이핑 광학계(220)는 제2 반사 광은 원형 링 또는 타원형 링으로 변경시킬 수 있다. 조리개를 이용하면, 제2 조명 광을 링 형태로 만들 수 있다.If the second illumination light has a ring shape, the beam shaping optical system 220 may change the second reflection light into a circular ring or an elliptical ring. By using the diaphragm, the second illumination light may be formed in a ring shape.
도 4는 본 발명의 다른 실시예에 따른 광학 검사 장치의 개념도이다. 도 4에 도시된 실시예는 경사 감지부(300)를 더 포함한다는 점에서, 도 1에 도시된 실시예와 차이가 있으므로, 여기에 대해서만 상세히 설명한다.4 is a conceptual diagram of an optical inspection device according to another embodiment of the present invention. Since the embodiment shown in FIG. 4 is different from the embodiment shown in FIG. 1 in that it further includes the tilt sensor 300, only this will be described in detail.
경사 감지부(300)는 제3 조명 광학계(310)와 제3 검출기(320)를 포함한다. 경사 감지부(300)는 시료(S)의 표면이 기울어져 있는지 검사한다.The tilt sensor 300 includes a third illumination optical system 310 and a third detector 320 . The inclination detection unit 300 inspects whether the surface of the specimen S is inclined.
제3 조명 광학계(310)는 제3 조명 광을 시료(S) 표면의 측정위치에 조사하는 역할을 한다. 본 실시예에서 제3 조명 광학계(310)는 제3 광원(311)과, 제3 광원(311)으로부터의 빔을 평행으로 만드는 시준기(312)와, 제3 빔 스플리터(313), 제4 빔 스플리터(315)를 포함하며, 이미지 획득부(100)의 핫 미러(121), 제1 빔 스플리터(113) 및 대물렌즈(115)도 제3 조명 광학계(310)의 일부로 사용한다.The third illumination optical system 310 serves to irradiate the third illumination light to the measurement position on the surface of the sample S. In this embodiment, the third illumination optical system 310 includes a third light source 311, a collimator 312 that makes beams from the third light source 311 parallel, a third beam splitter 313, and a fourth beam. A splitter 315 is included, and the hot mirror 121, the first beam splitter 113, and the objective lens 115 of the image acquisition unit 100 are also used as part of the third illumination optical system 310.
제3 광원(311)으로는 레이저 다이오드 또는 발광다이오드를 사용할 수 있다. 제3 광원(311)은 적외선 영역의 제3 조명 광을 생성한다. 제3 조명 광은 원형 광인 것이 바람직하다. 제3 조명 광은 제3 빔 스플리터(313)를 투과한 후 제4 빔 스플리터(315)에서 반사된다. 그리고 핫 미러(121)에서 다시 반사된다. 제3 조명 광으로 레이저를 사용하는 경우에는 제3 빔 스플리터(313)와 제4 빔 스플리터(315)로 편광 빔 스플리터를 사용하는 것이 바람직하다. 반사 및 투과 과정에서 광량이 줄어드는 것을 최소화할 수 있기 때문이다.A laser diode or a light emitting diode may be used as the third light source 311 . The third light source 311 generates third illumination light in the infrared region. The third illumination light is preferably a circular light. The third illumination light is reflected by the fourth beam splitter 315 after passing through the third beam splitter 313 . Then, it is reflected again at the hot mirror 121. When a laser is used as the third illumination light, it is preferable to use polarization beam splitters as the third beam splitter 313 and the fourth beam splitter 315 . This is because it is possible to minimize the decrease in the amount of light in the process of reflection and transmission.
그리고 핫 미러(121)에서 반사된 제3 조명 광은 제1 빔 스플리터(113)를 투과한 후 대물렌즈(115)에 입사한다. 대물렌즈(115)는 제3 조명 광을 시료(S) 표면의 측정위치에 집광시키고, 측정위치에서의 반사된 제3 반사광을 수집하는 역할을 한다. 본 실시예는 하나의 대물렌즈(115)를 이용하여 제1 조명 광, 제2 조명 광 및 제3 조명 광을 집광시키고, 제1 반사 광, 제2 반사 광 및 제3 조명 광을 수집한다는 장점이 있다.The third illumination light reflected from the hot mirror 121 is incident on the objective lens 115 after passing through the first beam splitter 113 . The objective lens 115 serves to condense the third illumination light onto the measuring position on the surface of the sample S and collect the third reflected light reflected from the measuring position. This embodiment has the advantage of condensing the first illumination light, the second illumination light, and the third illumination light by using one objective lens 115 and collecting the first reflection light, the second reflection light, and the third illumination light. there is
본 발명에서는 제3 조명 광으로 제1 조명 광과 다른 적외선을 사용하고, 핫 미러(121)를 사용하여 제3 반사 광과 제1 반사 광을 분리하여, 제1 검출기(130)로 제3 반사 광이 입사하는 것을 방지한다.In the present invention, infrared rays different from the first illumination light are used as the third illumination light, the third reflection light is separated from the first reflection light using the hot mirror 121, and the third reflection light is reflected to the first detector 130. Prevent light from entering.
대물렌즈(114)에서 수집된 제3 반사광은 다시 제1 빔 스플리터(113)를 투과한 후에 핫 미러(121)에서 반사된다. 적외선은 핫 미러(121)를 투과하지 못하므로, 적외선 영역의 제3 반사광이 제1 검출기(130)로 입사하지 않는다.The third reflected light collected by the objective lens 114 is reflected by the hot mirror 121 after passing through the first beam splitter 113 again. Since infrared rays cannot pass through the hot mirror 121 , the third reflected light in the infrared region does not enter the first detector 130 .
핫 미러(121)에서 반사된 제3 반사광은 제4 빔 스플리터(315)에서 제3 검출기(320) 쪽으로 반사된다. 그리고 제3 빔 스플리터(313)를 투과한 후 제3 검출기(320)에 입사한다. The third reflected light reflected from the hot mirror 121 is reflected toward the third detector 320 from the fourth beam splitter 315 . And, after passing through the third beam splitter 313, it is incident on the third detector 320.
제3 검출기(320)에는 제3 반사광이 결상되지 않은 상태로 입사된다. 즉, 제3 빔 스플리터(313)와 제3 검출기(320) 사이에는 결상을 위한 렌즈가 배치되지 않는다. 제3 검출기(320)는 4개의 광 다이오드를 구비하는 쿼드 셀, CCD, CMOS 카메라 등일 수 있다.The third reflected light is incident to the third detector 320 without forming an image. That is, a lens for forming an image is not disposed between the third beam splitter 313 and the third detector 320 . The third detector 320 may be a quad cell having four photodiodes, a CCD, a CMOS camera, or the like.
경사 감지부(300)는 제3 검출기(320)에 입사한 반사광의 중심이 제3 검출기(320)의 중심으로부터 벗어나는 정도를 기준으로 시료(S)의 표면이 기울어져 있는지 검사한다. 제3 반사광의 중심이 제3 검출기(320)의 중심과 일치하면 시료의 표면이 기울어지지 않은 것으로 판단하며, 중심에서 벗어난 정도와 방향을 통해서 시료의 표면이 기울어진 정도와 방향을 알 수 있다.The tilt detection unit 300 inspects whether the surface of the sample S is tilted based on the degree to which the center of the reflected light incident on the third detector 320 deviates from the center of the third detector 320 . If the center of the third reflected light coincides with the center of the third detector 320, it is determined that the surface of the sample is not tilted, and the degree and direction of the tilt of the surface of the sample can be known through the degree and direction out of the center.
이상에서 설명된 실시예들은 본 발명의 바람직한 실시예들을 설명한 것에 불과하고, 본 발명의 권리범위는 설명된 실시예들에 한정되는 것은 아니며, 본 발명의 기술적 사상과 특허청구범위 내에서 이 분야의 당업자에 의하여 다양한 변경, 변형 또는 치환할 수 있을 것이며, 그와 같은 실시예들은 본 발명의 범위에 속하는 것으로 이해되어야 한다.The embodiments described above are merely those of the preferred embodiments of the present invention, the scope of the present invention is not limited to the described embodiments, and within the technical spirit and claims of the present invention, Various changes, modifications, or substitutions may be made by those skilled in the art, and it should be understood that such embodiments fall within the scope of the present invention.
[부호의 설명][Description of code]
100: 이미지 획득부100: image acquisition unit
110: 제1 조명 광학계110: first illumination optical system
115: 대물렌즈115: objective lens
120: 결상 광학계120: imaging optical system
121: 핫 미러121: hot mirror
130: 제1 검출기130: first detector
200: 거리 감지부200: distance sensor
210: 제2 조명 광학계210: second illumination optical system
220: 빔 쉐이핑 광학계220: beam shaping optical system
221, 223: 실린더 렌즈221, 223: cylinder lens
230: 제2 검출기230: second detector
300: 경사 감지부300: slope detection unit
310: 제3 조명 광학계310: third illumination optical system
320: 제3 검출기320: third detector

Claims (10)

  1. 제1 조명 광을 시료 표면의 측정위치에 조사하도록 구성된 제1 조명 광학계와, 상기 시료 표면으로부터의 제1 반사광을 집광하여 제1 검출기에 결상시키도록 구성된 결상 광학계를 구비하는 이미지 획득부와,An image acquisition unit including a first illumination optical system configured to radiate a first illumination light to a measurement position on a sample surface, and an imaging optical system configured to collect first reflected light from the sample surface and form an image on a first detector;
    제2 조명 광을 시료 표면의 측정위치에 조사하도록 구성된 제2 조명 광학계와, 상기 시료 표면으로부터의 제2 반사광의 형태를 변경하는 빔 쉐이핑 광학계와, 상기 빔 쉐이핑 광학계를 통과한 제2 반사광이 결상되지 않은 상태로 입사되는 제2 검출기를 구비하며, 상기 빔 쉐이핑 광학계는 상기 제1 조명 광학계의 대물렌즈와 상기 시료 표면 사이의 거리에 따라서 상기 빔 쉐이핑 광학계를 통과한 제2 반사광의 형태가 변화하도록 구성된 거리 감지부를 포함하는 광학 검사 장치.A second illumination optical system configured to radiate a second illumination light to a measurement position on a sample surface, a beam shaping optical system configured to change a shape of a second reflected light from the sample surface, and the second reflected light passing through the beam shaping optical system forms an image. and a second detector that is incident without being incident, and the beam shaping optical system changes the shape of the second reflected light passing through the beam shaping optical system according to the distance between the object lens of the first illumination optical system and the sample surface. An optical inspection device comprising a configured distance detection unit.
  2. 제1항에 있어서,According to claim 1,
    상기 빔 쉐이핑 광학계는 상기 대물렌즈와 상기 시료 표면 사이의 거리가 기준 거리일 경우에는 제2 반사광의 형태를 원형으로 변경하고, 기준 거리와 다를 경우에는 타원형으로 변경하도록 구성된 광학 검사 장치.The beam shaping optical system is configured to change the shape of the second reflected light to a circular shape when the distance between the objective lens and the sample surface is a reference distance, and to change it to an elliptical shape when it is different from the reference distance.
  3. 제1항에 있어서,According to claim 1,
    상기 빔 쉐이핑 광학계는 파워 방향(power direction)이 서로 직교하는 한 쌍의 실린더 렌즈를 포함하는 광학 검사 장치.The beam shaping optical system includes a pair of cylinder lenses having power directions orthogonal to each other.
  4. 제1항에 있어서,According to claim 1,
    상기 제2 조명 광학계는 상기 제1 조명 광학계의 대물렌즈를 사용하여, 상기 시료 표면의 측정위치에 제2 조명 광을 집광시키고 상기 측정위치에서 반사된 제2 반사광을 수집하도록 구성된 광학 검사 장치.The second illumination optical system is configured to use the objective lens of the first illumination optical system to condense a second illumination light at a measurement position on the sample surface and collect second reflected light reflected at the measurement position.
  5. 제2항에 있어서,According to claim 2,
    상기 기준 거리는 상기 이미지 획득부의 초점이 맞는 거리인 광학 검사 장치.The reference distance is a distance at which the image acquisition unit is focused.
  6. 제1항에 있어서,According to claim 1,
    상기 제2 조명광은 적외선이며,The second illumination light is infrared,
    상기 제1 검출기에 상기 제2 조명광 및 상기 제2 반사광이 입사하는 것을 방지하도록 상기 제1 검출기와, 상기 대물렌즈 사이에 배치되는 핫 미러를 포함하는 광학 검사 장치.and a hot mirror disposed between the first detector and the objective lens to prevent the second illumination light and the second reflected light from being incident on the first detector.
  7. 제1항에 있어서,According to claim 1,
    상기 제2 검출기는 쿼드 셀(quad cell)인 광학 검사 장치.The second detector is an optical inspection device of a quad cell.
  8. 제1항에 있어서,According to claim 1,
    상기 제2 조명 광은 레이저이며,The second illumination light is a laser,
    상기 제2 빔 스플리터는 편광 빔 스플리터인 광학 검사 장치.The second beam splitter is a polarization beam splitter optical inspection device.
  9. 제1항에 있어서,According to claim 1,
    제3 조명 광을 시료 표면의 측정위치에 조사하도록 구성된 제3 조명 광학계와, 상기 시료 표면으로부터의 제3 반사광이 결상되지 않은 상태로 입사되는 제3 검출기를 포함하는 경사 감지부를 더 포함하는 광학 검사 장치.An optical inspection further comprising: a third illumination optical system configured to radiate third illumination light to a measurement position on a sample surface, and a tilt detection unit including a third detector into which third reflected light from the sample surface is incident in a non-imaged state. Device.
  10. 제9항에 있어서,According to claim 9,
    상기 제3 조명 광은 원형 광인 광학 검사 장치.The third illumination light is a circular light optical inspection device.
PCT/KR2022/018270 2022-01-25 2022-11-18 Optical inspection apparatus WO2023146085A1 (en)

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KR100939679B1 (en) * 2007-12-11 2010-02-03 (주)가하 Apparatus and method for adjusting the focus automatically
KR20130028065A (en) * 2010-02-23 2013-03-18 에이에스엠엘 네델란즈 비.브이. Lithographic apparatus and device manufacturing method
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KR102182571B1 (en) * 2020-06-05 2020-11-24 주식회사 엘퓨젼옵틱스 An optical device that is using infrared right for sample inspection and an optical device that is using infrared right for auto focusing on of the wafers
JP2021113987A (en) * 2015-07-17 2021-08-05 ザ トラスティース オブ コロンビア ユニバーシティ イン ザ シティ オブ ニューヨーク Systems and methods for three-dimensional imaging

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KR100939679B1 (en) * 2007-12-11 2010-02-03 (주)가하 Apparatus and method for adjusting the focus automatically
KR20130028065A (en) * 2010-02-23 2013-03-18 에이에스엠엘 네델란즈 비.브이. Lithographic apparatus and device manufacturing method
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