JP2009192520A5

JP2009192520A5 -

Info

Publication number: JP2009192520A5
Application number: JP2008169243A
Authority: JP
Filing date: 2008-06-27
Publication date: 2012-01-12

Description

このような目的達成のため、本発明に係る表面検査装置は、所定の繰り返しパターンが形成された被検基板の表面に偏光した照明光を照射する照明部と、前記照明光が照射された前記被検基板からの反射光による前記被検基板の表面像を形成する結像光学系と、前記表面像が形成される位置に配置された撮像面を有し、複数の画素を備える二次元撮像素子と、前記二次元撮像素子からの出力信号に基づいて前記反射光の偏光状態を算出し、該偏光状態に基づいて前記被検基板の欠陥を検出する検出部とを備え、前記結像光学系は、互いに透過軸の向きが異なる複数種の偏光素子を含む偏光素子アレイを有し、前記二次元撮像素子は、該二次元撮像素子の画素の領域がそれぞれ前記偏光素子の領域に対応するように配置される。 In order to achieve such an object, a surface inspection apparatus according to the present invention includes an illumination unit that irradiates polarized illumination light on a surface of a substrate to be tested on which a predetermined repetitive pattern is formed, and the illumination light that has been irradiated Two-dimensional imaging having an imaging optical system for forming a surface image of the test substrate by reflected light from the test substrate and an imaging surface disposed at a position where the surface image is formed, and having a plurality of pixels comprising a device, wherein the calculating the polarization state of the reflected light based on an output signal from the two-dimensional imaging device, and a detecting section for detecting a defect in the inspection target substrate based on the polarization state, said imaging optical The system includes a polarizing element array including a plurality of types of polarizing elements having different transmission axis directions, and the two-dimensional imaging element has a pixel area corresponding to the polarizing element area, respectively. Are arranged as follows.

なお、上述の発明において、前記偏光状態は、前記反射光が楕円偏光である場合の楕円率および長軸方位角のうち少なくとも一方であり、前記検出部は、前記二次元撮像素子からの出力信号の強度に基づいて前記偏光状態を算出し、該偏光状態に基づいて前記被検基板の欠陥を検出することが好ましい。 In the above-described invention, the polarization state is at least one of ellipticity and major axis azimuth when the reflected light is elliptically polarized, and the detection unit outputs an output signal from the two-dimensional image sensor. It is preferable to calculate the polarization state based on the intensity of the light and detect a defect of the substrate to be detected based on the polarization state .

また、上述の発明において、前記検出部は、前記二次元撮像素子からの出力信号に基づいて前記偏光状態を信号強度として算出し、該信号強度と、記憶部に予め記憶された正常パターンでの信号強度とを比較して、前記被検基板の欠陥を検出することが好ましい。 In the above-described invention, the detection unit calculates the polarization state as a signal intensity based on an output signal from the two-dimensional image sensor, and the signal intensity and a normal pattern stored in advance in the storage unit . It is preferable to detect a defect of the test substrate by comparing the signal intensity .

さらに、上述の発明において、前記偏光した照明光が直線偏光であることが好ましい。 Furthermore, in the above-described invention, it is preferable that the polarized illumination light is linearly polarized light .

また、上述の発明において、前記被検基板の表面における前記直線偏光の振動方向と前記繰り返しパターンの繰り返し方向とのなす角度を所定の角度に設定する角度設定部を備えることが好ましい。 In the above-described invention, it is preferable that an angle setting unit that sets an angle formed by the vibration direction of the linearly polarized light on the surface of the test substrate and the repeating direction of the repeating pattern to a predetermined angle is provided .

また、上述の発明において、前記照明光が平行光であることが好ましい。 Moreover, in the above-mentioned invention, it is preferable that the illumination light is parallel light .

また、上述の発明において、前記結像光学系は、前記照明光が照射された前記被検基板からの正反射光による前記被検基板の表面像を形成することが好ましい。
また、前記照明光は、前記繰り返しパターンの繰り返しピッチの２倍より長い波長の光であることが好ましい。
また、前記二次元撮像素子は、該二次元撮像素子の画素の領域がそれぞれ複数の画素単位で前記偏光素子の領域に対応するように配置されることが好ましい。 In the above-described invention, it is preferable that the imaging optical system forms a surface image of the test substrate by specular reflection light from the test substrate irradiated with the illumination light .
Further, the illumination light is preferably light having a wavelength longer than twice the repetition pitch of the repeating pattern.
Moreover, it is preferable that the two-dimensional image sensor is arranged so that the pixel area of the two-dimensional image sensor corresponds to the area of the polarization element in units of a plurality of pixels.

Claims

An illumination unit that irradiates polarized illumination light onto the surface of the test substrate on which a predetermined repeating pattern is formed;
An imaging optical system for forming a surface image of the test substrate by the reflected light from the test substrate irradiated with the illumination light ;
A two-dimensional imaging device having an imaging surface arranged at a position where the surface image is formed, and comprising a plurality of pixels;
A detection unit that calculates a polarization state of the reflected light based on an output signal from the two-dimensional image sensor, and detects a defect of the substrate to be detected based on the polarization state ;
The imaging optical system has a polarization element array including a plurality of types of polarization elements having different transmission axis directions,
The surface inspection apparatus , wherein the two-dimensional image sensor is arranged such that a pixel region of the two-dimensional image sensor corresponds to a region of the polarizing element .

The polarization state is at least one of ellipticity and major axis azimuth when the reflected light is elliptically polarized,
The said detection part calculates the said polarization state based on the intensity | strength of the output signal from the said two-dimensional image sensor, and detects the defect of the said test substrate based on this polarization state. The surface inspection apparatus described.

The detection unit calculates the polarization state as a signal intensity based on an output signal from the two-dimensional imaging device , and compares the signal intensity with a signal intensity in a normal pattern stored in advance in the storage unit. The surface inspection apparatus according to claim 1, wherein a defect of the substrate to be tested is detected.

The surface inspection apparatus according to any one of claims 1 to 3, wherein the polarized illumination light is linearly polarized light .

Surface inspection apparatus according to claim 4, characterized in that it comprises an angle setting unit for setting the angle between the repetition direction of the vibration direction and the repetitive pattern of the linearly polarized light on the surface of the test substrate at a predetermined angle .

The surface inspection apparatus according to claim 1, wherein the illumination light is parallel light .

7. The imaging optical system forms a surface image of the test substrate by regular reflection light from the test substrate irradiated with the illumination light . The surface inspection apparatus according to one item.

The surface inspection apparatus according to any one of claims 1 to 7, wherein the illumination light is light having a wavelength longer than twice the repetition pitch of the repetitive pattern.

9. The two-dimensional image sensor is arranged such that a pixel area of the two-dimensional image sensor corresponds to the area of the polarization element in units of a plurality of pixels, respectively. The surface inspection apparatus as described in any one of Claims.