Defect inspection method and defect inspection apparatus

Abstract

This invention provides a defect inspection method that can efficiently detect defects present in a silicon carbide substrate in a short amount of time. [Solution] A defect inspection method for detecting defects present in a silicon carbide substrate 100, comprising: an irradiation step of irradiating the entire silicon carbide substrate 100 with inspection light L1 to cause the silicon carbide substrate 100 to emit PL light; an imaging step of photographing the silicon carbide substrate 100 that is emitting PL light; an integration step of calculating an integrated value by accumulating the brightness values ​​of the pixels for each row and / or column, wherein the PL light image captured in the imaging step includes a plurality of pixels arranged in a matrix having a plurality of rows and a plurality of columns; an acquisition step of acquiring the brightness values ​​of the pixels in the rows and / or columns where the integrated value is above a certain level; and a first determination step of determining that the pixels are adhering pixels if the brightness values ​​of the pixels acquired in the acquisition step are above a threshold.

Claims

1. A defect inspection method for detecting defects present in a silicon carbide substrate, The process includes an irradiation step in which an inspection light is shone on the entire silicon carbide substrate to cause the silicon carbide substrate to emit PL light, A photographic step of photographing the silicon carbide substrate that is emitting PL light, The PL emission image captured in the aforementioned imaging step includes a plurality of pixels arranged in a matrix having a plurality of rows and a plurality of columns, and an integration step is performed to calculate an integrated value by accumulating the brightness values ​​of the pixels row and / or column by row, An acquisition step in which the brightness value of the pixels is acquired in rows and / or columns where the cumulative value is above a certain level, A first determination step is performed in which, if the brightness value of the pixel acquired in the acquisition step is equal to or greater than a threshold, the pixel is determined to be an attached object pixel. A defect inspection method that encompasses all of the above.

2. The first determination step determines that a pixel is defective if the brightness value of the pixel acquired in the acquisition step is within a predetermined brightness value range, and determines a candidate for a defective image based on the defective pixel. The defect inspection method according to claim 1, further comprising an extraction step of setting a rectangular region such that the contour of the defect image candidate is inscribed within it, and extracting from the defect image candidate candidates an extended defect image candidate that may be expanded based on the aspect ratio of the rectangular region.

3. The defect inspection method according to claim 2, further comprising the extraction step of extracting an expanded defect image from among the expanded defect image candidates based on the shape of the contour.

4. The aforementioned extraction process is, A binarization step is performed to generate a binarized image by binarizing the PL emission image, A contour generation step of generating the contour from the binarized image, If the shape of the contour is triangular, a second determination step is made to determine that it is a defective shape. To further encompass, The defect inspection method according to claim 3, wherein the expanded defect image is extracted based on the defect shape.

5. The defect inspection method according to claim 3, wherein in the extraction step, the extended defect image is extracted by using an algorithm that has been pre-trained using the candidate defect image, the candidate extended defect image, and the extended defect image as training data.

6. A defect inspection device for detecting defects present in a silicon carbide substrate, An irradiation means is provided to irradiate the entire silicon carbide substrate with inspection light to cause the silicon carbide substrate to emit PL light, A photographic means for photographing the silicon carbide substrate that is emitting PL light, A detection unit for detecting a defect image of the defect from the PL emission image captured by the aforementioned imaging means, Equipped with, The PL emission image includes a plurality of pixels arranged in a matrix having a plurality of rows and a plurality of columns, The detection unit is An integration means for calculating an integrated value obtained by accumulating the brightness values ​​of the aforementioned pixels row and / or column by row, In rows and / or columns where the cumulative value exceeds a certain level, an acquisition means for acquiring the brightness value of the pixels, A defect inspection device having the following features.

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