INSPECTION DEVICE AND SUBSTRATE PROCESSING APPARATUS

• US 20160314575A1
• Filed: 04/22/2016
• Published: 10/27/2016
• Est. Priority Date: 04/23/2015
• Status: Active Grant

• Current Assignee: SCREEN Holdings Co., Ltd.
• Original Assignee: SCREEN Holdings Co., Ltd.
• Inventors: NAKAGAWA, Koji, MATSUO, Tomohiro
• Granted Patent: US 10,043,694 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G03F 7/7065 Defects, e.g. optical inspection of patterned layer for defects
• CPC Class Codes: G06T 2207/30148 Semiconductor; IC; Wafer
• CPC Class Codes: G06T 7/001 using an image reference approach
• CPC Class Codes: H01L 21/67288 Monitoring of warpage, curvature, damage, defects or the like

Abstract

Surface image data of a non-defective sample substrate is acquired, and surface image data of a substrate to be inspected is acquired. Differences between gradation values are calculated for pixels of the surface image data of the substrate to be inspected and corresponding pixels of the surface image data of the sample substrate. A constant value is added to the difference between gradation values of each pixel. In the case where the value acquired by addition is in a predetermined allowable range, it is determined that there is no defect for the substrate to be inspected. In the case where the value acquired by addition is outside of the allowable range, it is determined that the substrate to be inspected is defective. A defect in appearance on the substrate to be inspected is detected based on a pixel of which the value is outside of the allowable range.

Claims

1. An inspector that performs appearance inspection for a substrate, comprising:

an image data acquirer that acquires image data of a substrate with no defect in appearance as first image data, and acquires image data of a substrate to be inspected as second image data by picking up an image of the substrate to be inspected; and

a determiner that calculates values related to differences between gradation values of pixels of the first image data acquired by the image data acquirer and gradation values of corresponding pixels of the of second image data acquired by the image data acquirer as pieces of difference information, and determines whether there is a defect in appearance on the substrate to be inspected based on whether each piece of calculated difference information is in a predetermined allowable range.

2. The inspector according to claim 1, wherein

the determiner detects a defect in appearance on the substrate based on a pixel of which the piece of difference information is outside of the allowable range.

3. The inspector according to claim 1, wherein

the pieces of difference information include values acquired by addition of a constant value to values of the differences.

4. The inspector according to claim 1, wherein

the determiner determines that there is a defect in appearance on the substrate to be inspected in the case where the number of pieces of difference information being outside of the allowable range is not less than a predetermined number.

5. The inspector according to claim 1, wherein

the determiner performs smoothing of the first image data acquired by the image data acquirer, produces first correction image data by subtracting a gradation value of each pixel of first image data after smoothing from a gradation value of each pixel of first image data before smoothing, performs smoothing of the second image data acquired by the image data acquirer, produces second correction image data by subtracting a gradation value of each pixel of second image data after smoothing from a gradation value of each pixel of second image data before smoothing, and calculates differences between gradation values of pixels of the produced first correction image data and gradation values of pixels of the produced second correction image data as the pieces of difference information for the pixels of the first image data and the corresponding pixels of the second image data.

24. A substrate processor arranged to be adjacent to an exposer that performs exposure processing on a substrate, comprising:

a coater that forms a photosensitive film on a substrate before exposure processing by the exposer;

a developer that performs development processing on the photosensitive film on the substrate after the exposure processing by the exposer; and

the inspector according to claim 1 that performs appearance inspection for the substrate after the formation of the photosensitive film by the coater.

25. The substrate processor according to claim 24, wherein

the inspector performs the appearance inspection for the substrate after the formation of the photosensitive film by the coater and after the development processing by the developer.

6. An inspector that performs appearance inspection for a substrate, comprising:

an image data acquirer that acquires image data of a substrate with no defect in appearance as first image data, and acquires image data of a substrate to be inspected as second image data by picking up an image of the substrate to be inspected;

a range setter that sets an allowable range for determining whether there is a defect in appearance on the substrate; and

a determiner that calculates values related to differences between gradation values of pixels of the first image data acquired by the image data acquirer and gradation values of pixels of the second image data acquired by the image data acquirer, the pixels of the first and second image data being considered to correspond to each other, and determines whether there is a defect in appearance on the substrate to be inspected based on whether each piece of calculated difference information is in the allowable range set by the range setter, wherein

the range setter calculates, for each of a plurality of predetermined target pixels of the first image data, differences between gradation values of a target pixel and a plurality of pixels in a constant region including the target pixel, determines, for each of the plurality of predetermined target pixels of the first image data, a representative value in a range from a minimum value to a maximum value of a plurality of differences by a predetermined method based on the plurality of calculated differences, and respectively sets values related to a minimum value and a maximum value of the plurality of representative values respectively determined for the plurality of target pixels as a lower limit value and an upper limit value of the allowable range.

7. The inspector according to claim 6, wherein

the predetermined method is a method of determining, for each of the plurality of predetermined target pixels of the first image data, an average value of the differences between a gradation value of the target pixel and gradation values of the plurality of pixels in the constant region including the target pixels as the representative value.

8. The inspector according to claim 6, wherein

the predetermined method is a method of determining, for each of the plurality of predetermined target pixels of the first image data, a maximum value of the differences between a gradation value of the target pixel and gradation values of the plurality of pixels in the constant region including the target pixels as the representative value.

9. The inspector according to claim 6, wherein

the pieces of difference information include values acquired by addition of a constant value to differences between gradation values of pixels of the first image data and gradation values of pixels of the second image data, the pixels of the first and second image data being considered to correspond to each other, and

values related to the minimum value and the maximum value of the plurality of representative values include values acquired by respective addition of the constant value to the minimum value and the maximum value of the plurality of representative values.

10. The inspector according to claim 6, wherein

the range setter sets a first value smaller than the minimum value of the plurality of representative values by a predetermined value as the lower limit value of the allowable range instead of the value related to the minimum value of the plurality of representative values, and sets a second value larger than the maximum value of the plurality of representative values by a predetermined value as the upper limit value of the allowable range instead of the value related to the maximum value of the plurality of representative values.

11. The inspector according to claim 6, wherein

the determiner detects a defect in appearance on the substrate based on a pixel of which a piece of difference information is outside of the allowable range.

12. The inspector according to claim 6, wherein

the determiner determines that there is a defect in appearance on the substrate to be inspected in the case where the number of pieces of difference information outside of the allowable range is not less than a predetermined number.

13. The inspector according to claim 6, wherein

the determiner performs smoothing of the first image data acquired by the image data acquirer, produces first correction image data by subtracting a gradation value of each pixel of first image data after smoothing from a gradation value of each pixel of first image data before smoothing, performs smoothing of the second image data acquired by the image data acquirer, produces second correction image data by subtracting a gradation value of each pixel of second image data after smoothing from a gradation value of each pixel of second image data before smoothing, and calculates differences between gradation values of pixels of the produced first correction data and gradation values of pixels of the produced second correction data, the pixels of the produced first and second correction data being considered to correspond to each other, as the pieces of difference information for the pixels of the first image data and corresponding pixels of the second image data, and

the range setter calculates, for each of a plurality of target pixels of the first correction image data produced by the determiner instead of the first image data, differences between a gradation value of the target pixel and gradation values of the plurality of pixels in the constant region including the target pixel, and determines, for each of the plurality of target pixels of the first correction image data produced by the determiner instead of the first image data, the representative value in the range from the minimum value to the maximum value of the plurality of differences by the predetermined method based on the plurality of calculated differences.

26. A substrate processor arranged to be adjacent to an exposer that performs exposure processing on a substrate, comprising:

a coater that forms a photosensitive film on the substrate before the exposure processing by the exposer;

a developer that performs development processing on the photosensitive film on the substrate before the exposure processing by the exposer; and

the inspector according to claim 6 that performs appearance inspection for the substrate after the formation of the photosensitive film by the coater.

27. The substrate processor according to claim 26, wherein

the inspector performs the appearance inspection for the substrate after the formation of the photosensitive film by the coater and the development processing by the developer.

14. An inspector that performs appearance inspection for a substrate, comprising:

an image data acquirer that acquires image data indicating a first image of a substrate with no defect in appearance as first image data, and acquires image data indicating a second image of a substrate to be inspected as second image data by picking up an image of the substrate to be inspected;

a corrector that corrects correspondence relationships between pixels of the first image data and pixels of the second image data; and

a determiner that calculates values related to differences between gradation values of pixels of the first image data acquired by the image data acquirer and gradation values of corresponding pixels of the second image data acquired by the image data acquirer as pieces of difference information based on the correspondence relationship corrected by the corrector, and determines whether there is a defect in appearance on the substrate to be inspected based on whether each piece of calculated difference information is in a predetermined allowable range, wherein

the first image is constituted by a plurality of first unit images,

the first image data includes a plurality of pieces of first unit image data respectively indicating the plurality of first unit images,

the second image is constituted by a plurality of second unit images,

the second image data includes a plurality of pieces of second unit image data respectively indicating the plurality of second unit images, and

the corrector detects relative deviation amounts between first and second unit images by comparing the pieces of first unit image data of the plurality of first unit images and the pieces of the second unit image data of the plurality of second unit images, the plurality of first and second unit images being located at corresponding positions, calculates a deviation amount for every pixel of the first and second images based on a plurality of deviation amounts detected for the plurality of first and second unit images, and corrects the correspondence relationship between a pixel of the first image data and a pixel of the second image data based on the calculated deviation amount for every pixel to resolve the deviation.

15. The inspector according to claim 14, wherein

the determiner detects a defect in appearance on the substrate based on a pixel of which the piece of difference information is outside of the allowable range.

16. The inspector according to claim 14, wherein

the corrector

calculates, for first and second unit images located at positions corresponding to each other, a plurality of coincidence degrees indicating degrees of coincidence between pieces of one unit image data and pieces of another unit image data based on differences between gradation values of pixels located at corresponding positions, while moving the other unit image with respect to the one unit image,

detects a movement amount of the other unit image in the case where the calculated coincidence degree is maximized as a relative deviation amount between the first and second unit images.

17. The inspector according to claim 14, wherein

the corrector

calculates, for first and second unit images located at positions corresponding to each other, a plurality of coincidence degrees indicating degrees of coincidence between pieces of one unit image data and pieces of another unit image data based on differences between gradation values of pixels located at corresponding positions, while moving the other unit image with respect to the one unit image,

detects, in the case where magnitude of variations of the calculated coincidence degrees is larger than a predetermined threshold value, a movement amount of the other unit image in the case where the coincidence degree is in a predetermined range of the coincidence degree and the deviation amount is minimized as a relative deviation amount between the first and second unit images, and

interpolates, in the case where magnitude of variations of the calculated coincidence degrees is not more than the predetermined threshold value, a relative deviation amount between the first and second unit images based on a deviation amount detected for other first and second unit images adjacent to the first and second unit images.

18. The inspector according to claim 14, wherein

each of the plurality of first and second unit images includes a representative pixel located at a predetermined position in the unit image, and

the corrector determines a relative deviation amount detected for each of the plurality of first and second unit images as a relative deviation amount for each representative pixel of each of the plurality of first and second unit images, and interpolates a deviation amount of pixels except for the plurality of representative pixels of the first and second pixels based on the determined deviation amount for every representative pixel.

19. The inspector according to claim 14, further comprising an emphasis processor that performs emphasis processing on the first and second image data such that contrast between the first and second images is emphasized under a predetermined condition, wherein

the corrector detects the relative deviation amount between the first and second unit images by comparing the pieces of first and second unit image data on which the emphasis processing is performed by the emphasis processor.

20. The inspector according to claim 14, further comprising an optimization processor that optimizes a deviation amount for every pixel calculated by the corrector, wherein

the optimization processor calculates differences between the deviation amount calculated for each pixel and correction amounts of a plurality of pixels surrounding the pixel, determines whether to treat the pixel as a target of interpolation based on a result of calculation, and determines, for each of one or a plurality of pixels that are treated as the target of interpolation, a deviation amount of the pixel based on a deviation amount calculated for one or a plurality of pixels that is not treated as a target of interpolation among pixels surrounding the pixel, and

the corrector performs correction of the correspondence relationship based on a deviation amount for every pixel optimized by the optimization processor.

21. The inspector according to claim 14, wherein

the pieces of difference information include values acquired by addition of a constant value to values of differences between gradation values of pixels of the first image data and gradation values of corresponding pixels of the second image data.

22. The inspector according to claim 14, wherein

the determiner determines that there is a defect in appearance on the substrate to be inspected in the case where the number of pieces of difference information outside of the allowable range is not less than a predetermined number.

23. The inspector according to claim 14, wherein

the determiner performs smoothing of the first image data, produces first correction image data by subtracting a gradation value of each pixel of first image data after smoothing from a gradation value of each pixel of first image data before smoothing, performs smoothing of the second image data, produces second correction image data by subtracting a gradation value of each pixel of second image data after smoothing from a gradation value of each pixel of second image data before smoothing, and calculates differences between gradation values of pixels of the first correction image data produced based on correspondence relationships corrected by the corrector and gradation values of corresponding pixels of the second correction image data produced based on the correspondence relationships corrected by the corrector as the pieces of difference information for pixels of the first image data and corresponding pixels of the second image data.

28. A substrate processor arranged to be adjacent to an exposer that performs exposure processing on a substrate, comprising:

a coater that forms a photosensitive film on the substrate before the exposure processing by the exposer;

a developer that performs development processing on the photosensitive film on the substrate after the exposure processing by the exposer; and

the inspector according to claim 14 that performs appearance inspection for the substrate after the formation of the photosensitive film by the coater.

29. The substrate processor according to claim 28, wherein

the inspector performs the appearance inspection for the substrate after the formation of the photosensitive film by the coater and after the development processing by the developer.