Apparatus for measuring film thickness formed on object, apparatus and method for measuring spectral reflectance of object, and apparatus and method of inspecting foreign material on object

Abstract

A film thickness measurement apparatus (1) comprises an ellipsometer (3) for acquiring a polarization state of a film on a substrate (9) and a light interference unit (4) for acquiring spectral intensity of the film on the substrate (9). In an optical system (45) of the light interference unit (4), a light shielding pattern (453a) is disposed in an aperture stop part (453), and an illumination light from a light source (41) is emitted to the substrate (9) through the optical system (45). A reflected light from the substrate (9) is guided to a light shielding pattern imaging part (43), where an image of the light shielding pattern (453a) is acquired. When the ellipsometer (3) performs a film thickness measurement, a tilt angle of the substrate (9) is obtained on the basis of the image of the light shielding pattern (453a) and a light receiving unit (32) acquires a polarization state of the reflected light. An calculation part (51) obtains a thickness of a film with high precision from the polarization state of the reflected light by using the obtained tilt angle.

Description

technical field [0001] The invention relates to a technique for measuring the thickness of a thin film formed on an object, a technique for measuring the spectral reflection coefficient of an object, and a technique for detecting foreign matter on an object. Background technique [0002] As a method for measuring the thickness of a thin film formed on the surface of an object, ellipsometry or reflectance spectroscopy, or a method called white light interferometry that does not involve ellipsometry (hereinafter, these two methods called "white light interferometry, etc."). Generally speaking, ellipsometry allows high-precision film thickness measurement of thin films; while measurements compared with ellipsometry, white light interferometry, etc. allow measurement of thicker films or multi-layer films. [0003] Japanese Patent Application Laid-Open Publication No. 61-182507 discloses a method for determining the thickness of a film on an object from the refractive index meas...

AI Technical Summary

Problems solved by technology

In addition, since the measurement area is very small, it is impossible to achieve high-precision film thickness measurement when extremely tiny foreign matter (such as submicron particles) adheres to the surface of the object

[0006] On the other hand, in white light interferometry etc., it is necessary to correct the measurement using a reference object whose reflection coefficient is known, and if this reflection coefficient changes due to natural oxidation of the surface of the reference object, it is impossible to correct the measurement correctly value

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