US5864394A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Surface inspection system
Assignee: Tencor Instruments Inc
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Filing: 1995-09-29
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Granted: 1999-01-26
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Expires: 2015-09-29
Abstract
Abstract A high throughput surface inspection system with enhanced detection sensitivity is described. The acquired data is processed in real time at a rate of below 50 MHz thereby reducing the cost for data processing. Anomalies are detected and verified by comparing adjacent repeating patterns and the height of the surface is monitored and corrected dynamically to reduce misregistration errors between adjacent repeating patterns. Local thresholds employing neighborhood information are used for detecting and verifying the presence of anomalies. The sampled point spread function of the combined illumination and collection system is exploited for anomaly detection and verification.
Inventors
- 👤 John R. Jordan, III
- 👤 Mehrdad Nikoonahad
- 👤 Keith B. Wells
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 12:53
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/95; G01N21/956; G01N21/95623; G01N21/94; G01N21/9501; G01N21/95607; G01R; G01R31/00; G01R31/28; G01R31/302; G01R31/308; G01N21/8806; G01N2021/8822; G01N2021/8825; G01R31/282; G01R31/2831; H; H10; H10P; H10P74/00; H10P74/20; H10P74/203
Claims Analysis
Total Claims: 130
Claim 1
Independent Claim
150 words
An inspection system for detecting anomalies on a surface, comprising: means for optically scanning the surface; means for collecting light scattered by the surface and deriving an intensity value for at least a first pixel location from the collected light; means for determining an error threshold for said at least first pixel location from intensity values stored for at least a corresponding second pixel location and its neighboring pixel locations of a reference image of the surface, said error threshold being determined by the difference between an intensity value stored for the second pixel location and a maximum or minimum of intensity values stored for the second pixel location and its neighboring pixel locations in the reference image; and means for identifying anomalies by comparing the difference between the intensity value for the at least first pixel location and that stored for the second pixel location to said error threshold.
Claim 2
Dependent Claim
150 words
An inspection system for detecting anomalies on a surface, comprising: means for optically scanning the surface; means for collecting light scattered by the surface and deriving an intensity value for at least a first pixel location from the collected light; means for determining an error threshold for said at least first pixel location from intensity values stored for at least a corresponding second pixel location and its neighboring pixel locations of a reference image of the surface, said error threshold being determined by the difference between an intensity value stored for the second pixel location and a maximum or minimum of intensity values stored for the second pixel location and its neighboring pixel locations in the reference image; and means for identifying anomalies by comparing the difference between the intensity value for the at least first pixel location and that stored for the second pixel location to said error threshold.
Claim 3
Dependent Claim
54 words
The system of claim 1, said surface having a plurality of repeating patterns thereon, said at least first and second pixel locations being in adjacent patterns, wherein said determining means includes buffer means storing the intensity values for said second pixel location and its neighboring pixel locations of the reference image of the surface.
Claim 4
Dependent Claim
43 words
The inspection system of claim 1, wherein the intensity value of collected light for the first pixel location and the stored intensity values for said second pixel location are spatially registered to an accuracy of better than plus or minus a pixel location.
Claim 5
Dependent Claim
48 words
The system of claim 3, wherein said optically scanning means directs a focused light beam at an oblique angle to scan said surface, said system further comprising means for measuring specular reflection of the light beam and for dynamically correcting the height of the surface during the scan.
Claim 6
Dependent Claim
59 words
The system of claim 1, wherein the intensity value of collected light for the first pixel location and the stored intensity values for said second pixel location are spatially registered to an accuracy of better than plus or minus a multiple of a pixel location, and wherein said determining means interpolates by multiplying the error threshold by a multiple.
Claim 7
Dependent Claim
33 words
The system of claim 1, said collecting and deriving means deriving said intensity value for said first pixel location from the collected light at said first pixel location and its adjacent pixel locations.
Claim 8
Dependent Claim
74 words
The system of claim 1, said system having a point spread function with said second pixel location at or near the peak of the function, wherein the neighboring pixel locations adjacent to said second pixel location form a two dimensional array defining a matrix having a center with said second pixel location at the center of the matrix, said matrix covering substantially the point spread function of the system above a predetermined intensity level.
Claim 9
Dependent Claim
13 words
The system of claim 7, said matrix being a three by three matrix.
Claim 10
Dependent Claim
47 words
The system of claim 1, wherein said identifying means also compares the difference between the intensity value for the first pixel location and that stored for the second pixel location to a second threshold that is proportional to the intensity value stored for the second pixel location.
Claim 11
Dependent Claim
41 words
The system of claim 1, wherein said identifying means also compares the difference between the intensity value for the first pixel location and that stored for the second pixel location to a third threshold that is a function of system noise.
Claim 12
Dependent Claim
127 words
The system of claim 1, wherein said collecting and deriving means derives intensity values for said first pixel location and for its adjacent pixel locations from the collected light; said system further comprising: a memory storing intensity values for the second pixel location of a reference image of the surface, and for neighboring pixel locations of the second pixel in the reference image corresponding in position to the adjacent pixel locations of the at least first pixel location; wherein said identifying means also identifies anomalies by ascertaining whether each of some of the intensity values for the first pixel location and its adjacent pixel locations exceeds or is less than that stored for the corresponding pixel location of the second pixel location and its neighboring pixel locations.
Claim 13
Dependent Claim
104 words
The system of claim 11, said system having a point spread function with said first pixel location at or near the peak of the function, wherein the pixel locations adjacent to said first pixel location form a two dimensional first matrix with the at least first pixel location at the center of the first matrix, said first matrix covering substantially the point spread function of the system above a predetermined threshold, said neighboring pixel locations of the second pixel location forming a second matrix of the same size as the first matrix with the second pixel location at the center of the second matrix.
Claim 14
Dependent Claim
51 words
The system of claim 12, wherein said identifying means identifies anomalies by ascertaining whether each of the intensity values for the first pixel location and its adjacent pixel locations exceeds or is less than that stored for the corresponding pixel location of the second pixel location and its neighboring pixel locations.
Claim 15
Dependent Claim
15 words
The system of claim 12, said first and second matrices being three by three matrices.
Claim 16
Dependent Claim
45 words
The system of claim 1, further comprising means for verifying the identified anomaly by ascertaining whether the intensity value of the first pixel location is a multiple of the intensity value of second pixel location, said multiple being in the range of 2 to 16.
Claim 17
Dependent Claim
92 words
The system of claim 1, further comprising: a memory storing intensity values for said second pixel location and its neighboring pixel locations; and means for verifying an identified anomaly by convolving a convolution matrix with the intensity values at said first pixel location and its adjacent pixel locations to obtain a first convolved value, and with the intensity values at said second pixel location and its neighboring pixel locations to obtain a second convolved value, and determining whether the difference between the first and second convolved values exceeds a predetermined convolution threshold.
Claim 18
Dependent Claim
14 words
The system of claim 16, said convolution threshold being a function of system noise.
Claim 19
Dependent Claim
15 words
The system of claim 16, said convolution threshold being proportional to the second convolved value.
Claim 20
Dependent Claim
157 words
The system of claim 16, said system having a point spread function with said first pixel location at or near the peak of the function, wherein the pixel locations adjacent to said first pixel location form a two dimensional first pixel location matrix with the at least first pixel location at the center of the first pixel location matrix, said first pixel location matrix covering substantially the point spread function of the system, said neighboring pixel locations of the second pixel location forming a second pixel location matrix of the same size as the first pixel location matrix with the second pixel location at the center of the second pixel location matrix; wherein the verifying means convolves said convolution matrix with the intensity values at said first pixel location matrix to obtain said first convolved value and convolves said convolution matrix with the intensity values at said second pixel location matrix to obtain said second convolved value.
Claim 21
Dependent Claim
21 words
The system of claim 19, said convolution matrix and said first and second pixel location matrices being five by five matrices.
Claim 22
Dependent Claim
148 words
An inspection system for detecting anomalies on a surface, comprising: means for optically scanning the surface; means for collecting light scattered by the surface and deriving intensity values for said first pixel location and for its adjacent pixel locations from the collected light; a memory storing intensity values for a second pixel location of a reference image of the surface, said second pixel location corresponding in position to the at least first pixel location, and for neighboring pixel locations of the second pixel in the reference image corresponding in position to the adjacent pixel locations of the at least first pixel location; means for identifying anomalies by ascertaining whether each of some of the intensity values for the first pixel location and its adjacent pixel locations exceeds or is less than that stored for the corresponding pixel location of the second pixel location and its neighboring pixel locations.
Claim 23
Dependent Claim
148 words
An inspection system for detecting anomalies on a surface, comprising: means for optically scanning the surface; means for collecting light scattered by the surface and deriving intensity values for said first pixel location and for its adjacent pixel locations from the collected light; a memory storing intensity values for a second pixel location of a reference image of the surface, said second pixel location corresponding in position to the at least first pixel location, and for neighboring pixel locations of the second pixel in the reference image corresponding in position to the adjacent pixel locations of the at least first pixel location; means for identifying anomalies by ascertaining whether each of some of the intensity values for the first pixel location and its adjacent pixel locations exceeds or is less than that stored for the corresponding pixel location of the second pixel location and its neighboring pixel locations.
Claim 24
Dependent Claim
105 words
The system of claim 21, said system having a point spread function with said first pixel location at or near the peak of the function, wherein the pixel locations adjacent to said first pixel location form a two dimensional first matrix with the at least first pixel location at the center of the first matrix, said first matrix covering substantially the point spread function of the system above a predetermined intensity level, said neighboring pixel locations of the second pixel location forming a second matrix of the same size as the first matrix with the second pixel location at the center of the second matrix.
Claim 25
Dependent Claim
15 words
The system of claim 22, said first and second matrices being three by three matrices.
Claim 26
Dependent Claim
54 words
The system of claim 21, said surface having a plurality of repeating patterns thereon, said at least first and second pixel locations being in adjacent patterns, wherein said determining means includes buffer means storing the intensity values for said second pixel location and its neighboring pixel locations of the reference image of the surface.
Claim 27
Dependent Claim
43 words
The inspection system of claim 21, wherein the intensity value of collected light for the first pixel location and the stored intensity values for said second pixel location are spatially registered to an accuracy of plus or minus a pixel location or better.
Claim 28
Dependent Claim
48 words
The system of claim 25, wherein said optically scanning means directs a focused light beam at an oblique angle to scan said surface, said system further comprising means for measuring specular reflection of the light beam and for dynamically correcting the height of the surface during the scan.
Claim 29
Dependent Claim
100 words
An inspection system for determining an anomaly on a surface, comprising: means for providing the intensity value for at least a first pixel location on the surface; a memory storing an intensity value for at least a second pixel location of a reference image of the surface, said second pixel location corresponding in position to the at least first pixel location; means for verifying the anomaly by ascertaining whether the intensity value of the at least first pixel location is a multiple of the intensity value of second pixel location, said multiple being in the range of 2 to 16.
Claim 30
Dependent Claim
100 words
An inspection system for determining an anomaly on a surface, comprising: means for providing the intensity value for at least a first pixel location on the surface; a memory storing an intensity value for at least a second pixel location of a reference image of the surface, said second pixel location corresponding in position to the at least first pixel location; means for verifying the anomaly by ascertaining whether the intensity value of the at least first pixel location is a multiple of the intensity value of second pixel location, said multiple being in the range of 2 to 16.
Claim 31
Dependent Claim
159 words
The system of claim 27, said system having a point spread function with said at least first pixel location at or near the peak of the function, wherein the pixel locations adjacent to said first pixel location form a two dimensional first matrix with the at least first pixel location at the center of the first matrix, said first matrix covering substantially the point spread function of the system above a predetermined intensity level, said neighboring pixel locations of the second pixel location forming a second matrix of the same size as the first matrix with the second pixel location at the center of the second matrix; wherein said providing means provides said intensity value for said first pixel location by deriving an average intensity value from the intensity values at the first matrix; and wherein the intensity value for the second pixel location stored in said memory is an average of the intensity values at the second matrix.
Claim 32
Dependent Claim
15 words
The system of claim 28, said first and second matrices being three by three matrices.
Claim 33
Dependent Claim
159 words
An inspection system for determining an anomaly on a surface, comprising: means for providing the intensity values for at least a first pixel location and its adjacent pixel locations on the surface; a memory storing intensity values for a second pixel location of a reference image of the surface, said second pixel location corresponding in position to the at least first pixel location, and for neighboring pixel locations of the second pixel in the reference image corresponding in position to the adjacent pixel locations of the at least first pixel location; means for determining an anomaly by convolving a convolution matrix with the intensity values at said first pixel location and its adjacent pixel locations to obtain a first convolved value, and with the intensity values at said second pixel location and its neighboring pixel locations to obtain a second convolved value, and determining whether the difference between the first and second convolved values exceeds a predetermined convolution threshold.
Claim 34
Dependent Claim
159 words
An inspection system for determining an anomaly on a surface, comprising: means for providing the intensity values for at least a first pixel location and its adjacent pixel locations on the surface; a memory storing intensity values for a second pixel location of a reference image of the surface, said second pixel location corresponding in position to the at least first pixel location, and for neighboring pixel locations of the second pixel in the reference image corresponding in position to the adjacent pixel locations of the at least first pixel location; means for determining an anomaly by convolving a convolution matrix with the intensity values at said first pixel location and its adjacent pixel locations to obtain a first convolved value, and with the intensity values at said second pixel location and its neighboring pixel locations to obtain a second convolved value, and determining whether the difference between the first and second convolved values exceeds a predetermined convolution threshold.
Claim 35
Dependent Claim
161 words
The system of claim 30, said system having a point spread function with said first pixel location at or near the peak of the function, wherein the pixel locations adjacent to said first pixel location form a two dimensional first pixel location matrix with the at least first pixel location at the center of the first pixel location matrix, said first pixel location matrix covering substantially the point spread function of the system above a predetermined threshold, said neighboring pixel locations of the second pixel location forming a second pixel location matrix of the same size as the first pixel location matrix with the second pixel location at the center of the second pixel location matrix; wherein the verifying means convolves said convolution matrix with the intensity values at said first pixel location matrix to obtain said first convolved value and convolves said convolution matrix with the intensity values at said second pixel location matrix to obtain said second convolved value.
Claim 36
Dependent Claim
21 words
The system of claim 31, said convolution matrix and said first and second pixel location matrices being five by five matrices.
Claim 37
Dependent Claim
14 words
The system of claim 31, wherein said surface is that of a non-patterned surface.
Claim 38
Dependent Claim
54 words
The system of claim 31, said surface having a plurality of repeating patterns thereon, said at least first and second pixel locations being in adjacent patterns, wherein said determining means includes buffer means storing the intensity values for said second pixel location and its neighboring pixel locations of the reference image of the surface.
Claim 39
Dependent Claim
48 words
The system of claim 31, wherein the convolution matrix has a perimeter and a core, and wherein the values at the perimeter are positive and the values at the core are negative or the values at the perimeter are negative and the values at the core are positive.
Claim 40
Dependent Claim
22 words
The system of claim 35, wherein said values at the perimeter are equal, and said values at the core are also equal.
Claim 41
Dependent Claim
23 words
The system of claim 35, wherein the sum of said values at the perimeter and said values at the core is substantially zero.
Claim 42
Dependent Claim
14 words
The system of claim 30, said convolution threshold being a function of system noise.
Claim 43
Dependent Claim
15 words
The system of claim 30, said convolution threshold being proportional to the second convolved value.
Claim 44
Dependent Claim
145 words
An inspection method for detecting anomalies on a surface, comprising the steps of: optically scanning the surface; collecting light scattered by the surface and deriving an intensity value for at least a first pixel location from the collected light; determining an error threshold for said at least first pixel location from intensity values stored for at least a corresponding second pixel location and its neighboring pixel locations of a reference image of the surface, said error threshold being determined by the difference between the intensity value stored for the second pixel location and a maximum or minimum of intensity values stored for the second pixel location and its neighboring pixel locations in the reference image; and identifying anomalies by comparing the difference between the intensity value for the at least first pixel location and that stored for the second pixel location to said error threshold.
Claim 45
Dependent Claim
145 words
An inspection method for detecting anomalies on a surface, comprising the steps of: optically scanning the surface; collecting light scattered by the surface and deriving an intensity value for at least a first pixel location from the collected light; determining an error threshold for said at least first pixel location from intensity values stored for at least a corresponding second pixel location and its neighboring pixel locations of a reference image of the surface, said error threshold being determined by the difference between the intensity value stored for the second pixel location and a maximum or minimum of intensity values stored for the second pixel location and its neighboring pixel locations in the reference image; and identifying anomalies by comparing the difference between the intensity value for the at least first pixel location and that stored for the second pixel location to said error threshold.
Claim 46
Dependent Claim
52 words
The method of claim 40, said surface having a plurality of repeating patterns thereon, said at least first and second pixel locations being in adjacent patterns, wherein said determining step includes storing the intensity values for said second pixel location and its neighboring pixel locations of the reference image of the surface.
Claim 47
Dependent Claim
52 words
The inspection method of claim 40, wherein said scanning, collecting and deriving steps are such that the intensity value of collected light for the first pixel location and the stored intensity values for said second pixel location are spatially registered to an accuracy of better than plus or minus a pixel location.
Claim 48
Dependent Claim
47 words
The method of claim 42, wherein said optically scanning step directs a focused light beam at an oblique angle to scan said surface, said method further comprising step of measuring specular reflection of the light beam and dynamically correcting the height of the surface during the scan.
Claim 49
Dependent Claim
59 words
The method of claim 40, wherein the intensity value of collected light for the first pixel location and the stored intensity values for said second pixel location are spatially registered to an accuracy of better than plus or minus a multiple of a pixel location, and wherein said determining step interpolates by multiplying the error threshold by a multiple.
Claim 50
Dependent Claim
33 words
The method of claim 40, said collecting and deriving step deriving said intensity value for said first pixel location from the collected light at said first pixel location and its adjacent pixel locations.
Claim 51
Dependent Claim
71 words
The method of claim 40, said method characterized by a point spread function with said second pixel location at or near the peak of the function, wherein the pixel locations adjacent to said second pixel location form a two dimensional matrix having a center with said second pixel location at the center of the matrix, said matrix covering substantially the point spread function characterizing the method above a predetermined intensity level.
Claim 52
Dependent Claim
13 words
The method of claim 46, said matrix being a three by three matrix.
Claim 53
Dependent Claim
47 words
The method of claim 40, wherein said identifying step also compares the difference between the intensity value for the first pixel location and that stored for the second pixel location to a second threshold that is proportional to the intensity value stored for the second pixel location.
Claim 54
Dependent Claim
44 words
The method of claim 40, wherein said identifying step also compares the difference between the intensity value for the first pixel location and that stored for the second pixel location to a third threshold that is a function of noise inherent in the method.
Claim 55
Dependent Claim
125 words
The method of claim 40, wherein said collecting and deriving step derives intensity values for said first pixel location and for its adjacent pixel locations from the collected light; said method further comprising: storing intensity values for the second pixel location of a reference image of the surface, and for neighboring pixel locations of the second pixel in the reference image corresponding in position to the adjacent pixel locations of the at least first pixel location; wherein said identifying step also identifies anomalies by ascertaining whether each of some of the intensity values for the first pixel location and its adjacent pixel locations exceeds or is less than that stored for the corresponding pixel location of the second pixel location and its neighboring pixel locations.
Claim 56
Dependent Claim
105 words
The method of claim 50, said method characterized by a point spread function with said first pixel location at or near the peak of the function, wherein the pixel locations adjacent to said first pixel location form a two dimensional first matrix with the at least first pixel location at the center of the first matrix, said first matrix covering substantially the point spread function characterizing the method above a predetermined threshold, said neighboring pixel locations of the second pixel location forming a second matrix of the same size as the first matrix with the second pixel location at the center of the second matrix.
Claim 57
Dependent Claim
51 words
The method of claim 51, wherein said identifying step identifies anomalies by ascertaining whether each of the intensity values for the first pixel location and its adjacent pixel locations exceeds or is less than that stored for the corresponding pixel location of the second pixel location and its neighboring pixel locations.
Claim 58
Dependent Claim
15 words
The method of claim 51, said first and second matrices being three by three matrices.
Claim 59
Dependent Claim
45 words
The method of claim 40, further comprising step for verifying the identified anomaly by ascertaining whether the intensity value of the first pixel location is a multiple of the intensity value of second pixel location, said multiple being in the range of 2 to 16.
Claim 60
Dependent Claim
88 words
The method of claim 40, further comprising: storing intensity values for said second pixel location and its neighboring pixel locations; and verifying an identified anomaly by convolving a convolution matrix with the intensity values at said first pixel location and its adjacent pixel locations to obtain a first convolved value, and with the intensity values at said second pixel location and its neighboring pixel locations to obtain a second convolved value, and ascertaining whether the difference between the first and second convolved values exceeds a predetermined convolution threshold.
Claim 61
Dependent Claim
17 words
The method of claim 55, said convolution threshold being a function of noise inherent in the method.
Claim 62
Dependent Claim
15 words
The method of claim 55, said convolution threshold being proportional to the second convolved value.
Claim 63
Dependent Claim
158 words
The method of claim 55, said method characterized by a point spread function with said first pixel location at or near the peak of the function, wherein the pixel locations adjacent to said first pixel location form a two dimensional first pixel location matrix with the at least first pixel location at the center of the first pixel location matrix, said first pixel location matrix covering substantially the point spread function characterizing the method, said neighboring pixel locations of the second pixel location forming a second pixel location matrix of the same size as the first pixel location matrix with the second pixel location at the center of the second pixel location matrix; wherein the verifying step convolves said convolution matrix with the intensity values at said first pixel location matrix to obtain said first convolved value and convolves said convolution matrix with the intensity values at said second pixel location matrix to obtain said second convolved value.
Claim 64
Dependent Claim
21 words
The method of claim 58, said convolution matrix and said first and second pixel location matrices being five by five matrices.
Claim 65
Dependent Claim
143 words
An inspection method for detecting anomalies on a surface, comprising the steps of: optically scanning the surface; collecting light scattered by the surface and deriving intensity values for said first pixel location and for its adjacent pixel locations from the collected light; storing intensity values for a second pixel location of a reference image of the surface, said second pixel location corresponding in position to the at least first pixel location, and for neighboring pixel locations of the second pixel in the reference image corresponding in position to the adjacent pixel locations of the at least first pixel location; identifying anomalies by ascertaining whether each of some of the intensity values for the first pixel location and its adjacent pixel locations exceeds or is less than that stored for the corresponding pixel location of the second pixel location and its neighboring pixel locations.
Claim 66
Dependent Claim
143 words
An inspection method for detecting anomalies on a surface, comprising the steps of: optically scanning the surface; collecting light scattered by the surface and deriving intensity values for said first pixel location and for its adjacent pixel locations from the collected light; storing intensity values for a second pixel location of a reference image of the surface, said second pixel location corresponding in position to the at least first pixel location, and for neighboring pixel locations of the second pixel in the reference image corresponding in position to the adjacent pixel locations of the at least first pixel location; identifying anomalies by ascertaining whether each of some of the intensity values for the first pixel location and its adjacent pixel locations exceeds or is less than that stored for the corresponding pixel location of the second pixel location and its neighboring pixel locations.
Claim 67
Dependent Claim
106 words
The method of claim 60, said method characterized by a point spread function with said first pixel location at or near the peak of the function, wherein the pixel locations adjacent to said first pixel location form a two dimensional first matrix with the at least first pixel location at the center of the first matrix, said first matrix covering substantially the point spread function characterizing the method above a predetermined intensity level, said neighboring pixel locations of the second pixel location forming a second matrix of the same size as the first matrix with the second pixel location at the center of the second matrix.
Claim 68
Dependent Claim
15 words
The method of claim 61, said first and second matrices being three by three matrices.
Claim 69
Dependent Claim
52 words
The method of claim 60, said surface having a plurality of repeating patterns thereon, said at least first and second pixel locations being in adjacent patterns, wherein said determining step includes storing the intensity values for said second pixel location and its neighboring pixel locations of the reference image of the surface.
Claim 70
Dependent Claim
43 words
The inspection method of claim 60, wherein the intensity value of collected light for the first pixel location and the stored intensity values for said second pixel location are spatially registered to an accuracy of plus or minus a pixel location or better.
Claim 71
Dependent Claim
48 words
The method of claim 64, wherein said optically scanning step directs a focused light beam at an oblique angle to scan said surface, said method further comprising step for measuring specular reflection of the light beam and for dynamically correcting the height of the surface during the scan.
Claim 72
Dependent Claim
97 words
An inspection method for determining an anomaly on a surface, comprising the steps of: providing the intensity value for at least a first pixel location on the surface; storing an intensity value for at least a second pixel location of a reference image of the surface, said second pixel location corresponding in position to the at least first pixel location; verifying the anomaly by ascertaining whether the intensity value of the at least first pixel location is a multiple of the intensity value of second pixel location, said multiple being in the range of 2 to 16.
Claim 73
Dependent Claim
97 words
An inspection method for determining an anomaly on a surface, comprising the steps of: providing the intensity value for at least a first pixel location on the surface; storing an intensity value for at least a second pixel location of a reference image of the surface, said second pixel location corresponding in position to the at least first pixel location; verifying the anomaly by ascertaining whether the intensity value of the at least first pixel location is a multiple of the intensity value of second pixel location, said multiple being in the range of 2 to 16.
Claim 74
Dependent Claim
160 words
The method of claim 66, said method characterized by a point spread function with said at least first pixel location at or near the peak of the function, wherein the pixel locations adjacent to said first pixel location form a two dimensional first matrix with the at least first pixel location at the center of the first matrix, said first matrix covering substantially the point spread function characterizing the method above a predetermined intensity level, said neighboring pixel locations of the second pixel location forming a second matrix of the same size as the first matrix with the second pixel location at the center of the second matrix; wherein said providing step provides said intensity value for said first pixel location by deriving an average intensity value from the intensity values at the first matrix; and wherein the intensity value for the second pixel location stored in said memory is an average of the intensity values at the second matrix.
Claim 75
Dependent Claim
15 words
The method of claim 67, said first and second matrices being three by three matrices.
Claim 76
Dependent Claim
156 words
An inspection method for determining an anomaly on a surface, comprising the steps of: providing the intensity values for at least a first pixel location and its adjacent pixel locations on the surface; storing intensity values for a second pixel location of a reference image of the surface, said second pixel location corresponding in position to the at least first pixel location, and for neighboring pixel locations of the second pixel in the reference image corresponding in position to the adjacent pixel locations of the at least first pixel location; determining an anomaly by convolving a convolution matrix with the intensity values at said first pixel location and its adjacent pixel locations to obtain a first convolved value, and with the intensity values at said second pixel location and its neighboring pixel locations to obtain a second convolved value, and determining whether the difference between the first and second convolved values exceeds a predetermined convolution threshold.
Claim 77
Dependent Claim
156 words
An inspection method for determining an anomaly on a surface, comprising the steps of: providing the intensity values for at least a first pixel location and its adjacent pixel locations on the surface; storing intensity values for a second pixel location of a reference image of the surface, said second pixel location corresponding in position to the at least first pixel location, and for neighboring pixel locations of the second pixel in the reference image corresponding in position to the adjacent pixel locations of the at least first pixel location; determining an anomaly by convolving a convolution matrix with the intensity values at said first pixel location and its adjacent pixel locations to obtain a first convolved value, and with the intensity values at said second pixel location and its neighboring pixel locations to obtain a second convolved value, and determining whether the difference between the first and second convolved values exceeds a predetermined convolution threshold.
Claim 78
Dependent Claim
162 words
The method of claim 69, said method characterized by a point spread function with said first pixel location at or near the peak of the function, wherein the pixel locations adjacent to said first pixel location form a two dimensional first pixel location matrix with the at least first pixel location at the center of the first pixel location matrix, said first pixel location matrix covering substantially the point spread function characterizing the method above a predetermined threshold, said neighboring pixel locations of the second pixel location forming a second pixel location matrix of the same size as the first pixel location matrix with the second pixel location at the center of the second pixel location matrix; wherein the verifying step convolves said convolution matrix with the intensity values at said first pixel location matrix to obtain said first convolved value and convolves said convolution matrix with the intensity values at said second pixel location matrix to obtain said second convolved value.
Claim 79
Dependent Claim
21 words
The method of claim 70, said convolution matrix and said first and second pixel location matrices being five by five matrices.
Claim 80
Dependent Claim
14 words
The method of claim 70, wherein said surface is that of a non-patterned surface.
Claim 81
Dependent Claim
52 words
The method of claim 70, said surface having a plurality of repeating patterns thereon, said at least first and second pixel locations being in adjacent patterns, wherein said determining step includes storing the intensity values for said second pixel location and its neighboring pixel locations of the reference image of the surface.
Claim 82
Dependent Claim
48 words
The method of claim 70, wherein the convolution matrix has a perimeter and a core, and wherein the values at the perimeter are positive and the values at the core are negative or the values at the perimeter are negative and the values at the core are positive.
Claim 83
Dependent Claim
22 words
The method of claim 74, wherein said values at the perimeter are equal, and said values at the core are also equal.
Claim 84
Dependent Claim
23 words
The method of claim 74, wherein the sum of said values at the perimeter and said values at the core is substantially zero.
Claim 85
Dependent Claim
17 words
The method of claim 69, said convolution threshold being a function of noise inherent in the method.
Claim 86
Dependent Claim
15 words
The method of claim 69, said convolution threshold being proportional to the second convolved value.
Claim 87
Independent Claim
191 words
A system for detecting anomalies on a surface; comprising: means for directing a focused beam of light at a grazing angle toward said surface; means for causing relative motion between the beam and the surface so that the entire surface is scanned with said beam; means for detecting the specular reflection from the said surface and dynamically measuring the height of the said surface during scan; means for dynamically correcting the height of said surface during scan; means for collecting light scattered from the surface and converting such light into an electrical signal; means for digitally processing said electrical signal for detecting anomalies, said digital processing means detecting anomalies by comparing the difference between the intensity value for at least a first pixel location and that stored for at least a second pixel location of a reference image of the surface to an error threshold, said error threshold being determined by the digitally processing means from the difference between the intensity value stored for the second pixel location and a maximum or minimum of intensity values stored for the second pixel location and its neighboring pixel locations of the reference image.
Claim 88
Independent Claim
191 words
A system for detecting anomalies on a surface; comprising: means for directing a focused beam of light at a grazing angle toward said surface; means for causing relative motion between the beam and the surface so that the entire surface is scanned with said beam; means for detecting the specular reflection from the said surface and dynamically measuring the height of the said surface during scan; means for dynamically correcting the height of said surface during scan; means for collecting light scattered from the surface and converting such light into an electrical signal; means for digitally processing said electrical signal for detecting anomalies, said digital processing means detecting anomalies by comparing the difference between the intensity value for at least a first pixel location and that stored for at least a second pixel location of a reference image of the surface to an error threshold, said error threshold being determined by the digitally processing means from the difference between the intensity value stored for the second pixel location and a maximum or minimum of intensity values stored for the second pixel location and its neighboring pixel locations of the reference image.
Claim 89
Dependent Claim
36 words
The system of claim 79, said directing means directing said beam to illuminate an area on the surface defining a spot, wherein the size of the spot is in the range of 5 to 15 micrometers.
Claim 90
Dependent Claim
23 words
The system of claim 79, wherein the grazing angle of illumination of the beam is in the range of 10 to 85 degrees.
Claim 91
Dependent Claim
61 words
The system of claim 79, wherein said relative motion causing means causes relative motion between the beam and the surface so that the beam scans a scan path covering substantially the entire surface, said path including a plurality of strips of sweeps, wherein each of at least some of such sweeps has a span shorter than the dimensions of the surface.
Claim 92
Dependent Claim
24 words
The system of claim 82, wherein the span of at least some of such sweeps is in the range of 2 to 10 mm.
Claim 93
Dependent Claim
54 words
The system of claim 79, said directing means directing said beam to illuminate a plurality of areas on the surface during the scan, each area on the surface defining a spot, said collecting and converting means converting the collected light into electrical signals representing light collected from 2 to 10 pixels within each spot.
Claim 94
Dependent Claim
32 words
The system of claim 79, wherein the detecting and measuring means includes a position sensitive detector for detecting the specular reflection from the surface and measuring the surface height of the wafer.
Claim 95
Dependent Claim
42 words
The system of claim 85, said dynamically correcting means including a piezostage, wherein the position sensitive detector provides a DC voltage output for controlling the piezostage which can dynamically correct the height of the wafer in response to the DC voltage output.
Claim 96
Dependent Claim
71 words
The system of claim 86, said digitally processing means detecting anomalies by comparing the intensity value for at least a first pixel location and that stored for at least a second pixel location of a previously scanned reference image of the surface, wherein the dynamically correcting means corrects the height of the wafer so that the first and second pixel locations are spatially aligned to within 0.25 of a pixel location.
Claim 97
Dependent Claim
78 words
The system of claim 79, said surface having a repeating pattern thereon, wherein said collecting and converting means collects light scattered by the surface at or near a first pixel location in a first pattern of the repeating pattern and converts such light into a first signal, and said processing means including a buffer for storing the electrical signal for a second pixel location from a pattern adjacent to said first pattern for comparison with the first signal.
Claim 98
Independent Claim
182 words
A method for detecting anomalies on a surface; comprising the steps of: directing a focused beam of light at a grazing angle toward said surface; causing relative motion between the beam and the surface so that the entire surface is scanned with said beam; detecting the specular reflection from the said surface and dynamically measuring the height of the said surface during scan; dynamically correcting the height of said surface during scan; collecting light scattered from the surface and converting such light into an electrical signal; and digitally processing said electrical signal for detecting anomalies, said digitally processing step detecting anomalies by comparing the difference between the intensity value for at least a first pixel location and that stored or at least second pixel location of a reference image of the surface to an error threshold, said error threshold being determined in the digitally processing step by the difference between the intensity value stored for the second pixel location and a maximum or minimum of intensity values stored for the second pixel location and its neighboring pixel locations of the reference image.
Claim 99
Independent Claim
182 words
A method for detecting anomalies on a surface; comprising the steps of: directing a focused beam of light at a grazing angle toward said surface; causing relative motion between the beam and the surface so that the entire surface is scanned with said beam; detecting the specular reflection from the said surface and dynamically measuring the height of the said surface during scan; dynamically correcting the height of said surface during scan; collecting light scattered from the surface and converting such light into an electrical signal; and digitally processing said electrical signal for detecting anomalies, said digitally processing step detecting anomalies by comparing the difference between the intensity value for at least a first pixel location and that stored or at least second pixel location of a reference image of the surface to an error threshold, said error threshold being determined in the digitally processing step by the difference between the intensity value stored for the second pixel location and a maximum or minimum of intensity values stored for the second pixel location and its neighboring pixel locations of the reference image.
Claim 100
Dependent Claim
36 words
The method of claim 89, said directing step directing said beam to illuminate an area on the surface defining a spot, wherein the size of the spot is in the range of 5 to 15 micrometers.
Claim 101
Dependent Claim
23 words
The method of claim 89, wherein the grazing angle of illumination of the beam is in the range of 10 to 85 degrees.
Claim 102
Dependent Claim
61 words
The method of claim 91, wherein said relative motion causing step causes relative motion between the beam and the surface so that the beam scans a scan path covering substantially the entire surface, said path including a plurality of strips of sweeps, wherein each of at least some of such sweeps has a span shorter than the dimensions of the surface.
Claim 103
Dependent Claim
54 words
The method of claim 91, said directing step directing said beam to illuminate a plurality of areas on the surface during the scan, each area on the surface defining a spot, said collecting and converting step converting the collected light into electrical signals representing light collected from 2 to 10 pixels within each spot.
Claim 104
Dependent Claim
71 words
The method of claim 91, said digitally processing step detecting anomalies by comparing the intensity value for at least a first pixel location and that stored for at least a second pixel location of a previously scanned reference image of the surface, wherein the dynamically correcting step corrects the height of the wafer so that the first and second pixel locations are spatially aligned to within 0.25 of a pixel location.
Claim 105
Independent Claim
162 words
A method for detecting anomalies on a surface of a semiconductor wafer; comprising: directing a focused beam of light towards said surface to illuminate an area of the surface defining a spot; causing relative motion between the beam and the wafer so that the beam scans a serpentine path covering substantially the entire surface; collecting light scattered along said path for detecting anomalies and converting the collected light to an electrical signal; wherein the spot size and said directing and causing steps are such that the beam substantially inspects the entire surface of the wafer at a throughput in excess of about 40 wafers per hour for 150 mm diameter wafers, at a throughput in excess of about 20 wafers per hour for 200 mm diameter wafers, and at a throughput in excess of about 10 wafers per hour for 300 mm diameter wafers; and digitally processing said electrical signal for detecting anomalies at a data clock rate less than 50 MHz.
Claim 106
Independent Claim
162 words
A method for detecting anomalies on a surface of a semiconductor wafer; comprising: directing a focused beam of light towards said surface to illuminate an area of the surface defining a spot; causing relative motion between the beam and the wafer so that the beam scans a serpentine path covering substantially the entire surface; collecting light scattered along said path for detecting anomalies and converting the collected light to an electrical signal; wherein the spot size and said directing and causing steps are such that the beam substantially inspects the entire surface of the wafer at a throughput in excess of about 40 wafers per hour for 150 mm diameter wafers, at a throughput in excess of about 20 wafers per hour for 200 mm diameter wafers, and at a throughput in excess of about 10 wafers per hour for 300 mm diameter wafers; and digitally processing said electrical signal for detecting anomalies at a data clock rate less than 50 MHz.
Claim 107
Dependent Claim
30 words
The method of claim 95, said directing step being such that the spot has a spot size whose minimum dimension is in the range of about 5 to 15 microns.
Claim 108
Independent Claim
118 words
A method for detecting anomalies on a surface, comprising the steps of: directing a focused beam of light towards said surface to illuminate an area of the surface defining a spot; causing relative motion between the beam and the surface so that the beam scans a serpentine path covering substantially the entire surface; collecting light scattered along said path for detecting anomalies and converting the collected light to an electrical signal; wherein the spot size and said directing and causing steps are such that the surface is inspected at a speed not less than about 1.5 cm 2 /s; and digitally processing said electrical signal for detecting anomalies at a data clock rate of less than 50 MHz.
Claim 109
Independent Claim
118 words
A method for detecting anomalies on a surface, comprising the steps of: directing a focused beam of light towards said surface to illuminate an area of the surface defining a spot; causing relative motion between the beam and the surface so that the beam scans a serpentine path covering substantially the entire surface; collecting light scattered along said path for detecting anomalies and converting the collected light to an electrical signal; wherein the spot size and said directing and causing steps are such that the surface is inspected at a speed not less than about 1.5 cm 2 /s; and digitally processing said electrical signal for detecting anomalies at a data clock rate of less than 50 MHz.
Claim 110
Dependent Claim
30 words
The method of claim 97, said directing step being such that the spot has a spot size whose minimum dimension is in the range of about 5 to 15 microns.
Claim 111
Independent Claim
128 words
A method for detecting anomalies on a surface, comprising the steps of: directing a beam of light towards said surface to illuminate an area of the surface defining a spot; causing relative motion between the beam and the surface so that the beam scans a serpentine path covering substantially the entire surface; and collecting light scattered along said path for detecting anomalies and converting the collected light to an electrical signal; said surface having dimensions of not less than 200 mm in any direction along the surface, wherein said directing and causing steps are such that the beam scans substantially the entire surface in about 50 to 90 seconds; and digitally processing said electrical signal for detecting anomalies at a data clock rate of less than 50 MHz.
Claim 112
Independent Claim
128 words
A method for detecting anomalies on a surface, comprising the steps of: directing a beam of light towards said surface to illuminate an area of the surface defining a spot; causing relative motion between the beam and the surface so that the beam scans a serpentine path covering substantially the entire surface; and collecting light scattered along said path for detecting anomalies and converting the collected light to an electrical signal; said surface having dimensions of not less than 200 mm in any direction along the surface, wherein said directing and causing steps are such that the beam scans substantially the entire surface in about 50 to 90 seconds; and digitally processing said electrical signal for detecting anomalies at a data clock rate of less than 50 MHz.
Claim 113
Dependent Claim
24 words
The method of claim 96, wherein the span of at least some of such sweeps is in the range of 2 to 10 mm.
Claim 114
Dependent Claim
30 words
The method of claim 99, said directing step being such that the spot has a spot size whose minimum dimension is in the range of about 5 to 15 microns.
Claim 115
Independent Claim
140 words
A method for detecting anomalies on a surface, comprising the steps of: directing a focused beam of light towards said surface to illuminate an area of the surface defining a spot whose size is in the range of about 5 to 15 micrometers; causing relative motion between the beam and the surface so that the beam scans a serpentine path covering substantially the entire surface, said surface having dimensions of not less than 200 mm in any direction along the surface, wherein said directing and causing steps are such that the beam scans substantially the entire surface in about 50 to 90 seconds; collecting light scattered along said path for detecting anomalies and converting the collected light to an electrical signal; and digitally processing said electrical signal for detecting anomalies at a data clock rate of less than 50 MHz.
Claim 116
Independent Claim
140 words
A method for detecting anomalies on a surface, comprising the steps of: directing a focused beam of light towards said surface to illuminate an area of the surface defining a spot whose size is in the range of about 5 to 15 micrometers; causing relative motion between the beam and the surface so that the beam scans a serpentine path covering substantially the entire surface, said surface having dimensions of not less than 200 mm in any direction along the surface, wherein said directing and causing steps are such that the beam scans substantially the entire surface in about 50 to 90 seconds; collecting light scattered along said path for detecting anomalies and converting the collected light to an electrical signal; and digitally processing said electrical signal for detecting anomalies at a data clock rate of less than 50 MHz.
Claim 117
Independent Claim
77 words
The method of claims 101, wherein the spot size and said directing and causing steps are such that the beam substantially inspects the entire surface of the wafer at a throughput in excess of about 40 wafers per hour for 150 mm diameter wafers, at a throughput in excess of about 20 wafers per hour for 200 mm diameter wafers, and at a throughput in excess of about 10 wafers per hour for 300 mm diameter wafers.
Claim 118
Dependent Claim
61 words
The method of claim 101, wherein said relative motion causing step causes relative motion between the beam and the surface so that the beam scans a scan path covering substantially the entire surface, said path including a plurality of strips of sweeps, wherein each of at least some of such sweeps has a span shorter than the dimensions of the surface.
Claim 119
Dependent Claim
61 words
The method of claim 103, said directing step directing said beam to illuminate a plurality of areas on the surface during the scan, each area on the surface defining a spot, said collecting and converting step converting the collected light into electrical signals representing light collected from N pixels within each spot, N being in the range of 2 to 10.
Claim 120
Dependent Claim
28 words
The method of claim 104, said data clock rate being proportional to N and the span of the sweeps and inversely proportional to the size of the spot.
Claim 121
Independent Claim
172 words
A system for detecting anomalies on a surface, comprising: means for directing a focused beam of light towards said surface at an oblique angle of θ from the normal direction to the surface to illuminate a plurality of areas on the surface during the scan, each such illuminated area on the surface defining a spot of size w, said collecting and converting step converting the collected light into electrical signals representing light collected from N pixels within each spot; means for causing relative motion between the beam and the surface so that the beam scans a serpentine path covering substantially the entire surface, said path including a plurality of strips of sweeps of effective length l shorter than the dimensions of the surface, wherein the beam scans each sweep in time T; means for collecting light scattered along said path for detecting anomalies and converting the collected light to an electrical signal; and means for digitally processing said electrical signal for detecting anomalies, at a data clock rate substantially proportional to Nl/wT.
Claim 122
Independent Claim
172 words
A system for detecting anomalies on a surface, comprising: means for directing a focused beam of light towards said surface at an oblique angle of θ from the normal direction to the surface to illuminate a plurality of areas on the surface during the scan, each such illuminated area on the surface defining a spot of size w, said collecting and converting step converting the collected light into electrical signals representing light collected from N pixels within each spot; means for causing relative motion between the beam and the surface so that the beam scans a serpentine path covering substantially the entire surface, said path including a plurality of strips of sweeps of effective length l shorter than the dimensions of the surface, wherein the beam scans each sweep in time T; means for collecting light scattered along said path for detecting anomalies and converting the collected light to an electrical signal; and means for digitally processing said electrical signal for detecting anomalies, at a data clock rate substantially proportional to Nl/wT.
Claim 123
Dependent Claim
106 words
The system of claim 106, said surface having a repeating pattern thereon, wherein said collecting and converting means collects light scattered by the surface at or near a first pixel location in a first pattern of the repeating pattern and converts such light into a first signal, and said processing means including a buffer for storing a second electrical signal for a second pixel location from a pattern adjacent to said first pattern for comparison with the first signal; wherein the processing means includes a buffer for storing the second electrical signal, said buffer means having a size proportional to N 2 ld cosθ/w 2 .
Claim 124
Dependent Claim
65 words
The system of claim 1, wherein each of the intensity values stored for the second pixel and for its neighboring pixel locations is an averaged intensity value over a neighborhood around each respective pixel location, and the intensity value for the first pixel location derived by the collecting and deriving means is an average of intensity values over a neighborhood around the first pixel location.
Claim 125
Dependent Claim
35 words
The system of claim 1, said determining means including a circuit for finding the maximum or minimum of stored intensity values for the second pixel location and its neighboring pixel locations in the reference image.
Claim 126
Dependent Claim
65 words
The method of claim 40, wherein each of the intensity values stored for the second pixel and for its neighboring pixel locations is an averaged intensity value over a neighborhood around each respective pixel location, and the intensity value for the first pixel location derived in the collecting and deriving step is an average of intensity values over a neighborhood around the first pixel location.
Claim 127
Dependent Claim
136 words
An inspection system for detecting anomalies on a surface, comprising: means for optically scanning the surface; means for collecting light scattered by the surface and deriving an intensity value for at least a first pixel location from the collected light; means for determining an error threshold for said at least first pixel location from intensity values stored for at least a corresponding second pixel location and its neighboring pixel locations of a reference image of the surface, said error threshold being determined by the difference between two intensity values stored for the second pixel location and its neighboring pixel locations in the reference image; and means for identifying anomalies by comparing the difference between the intensity value for the at least first pixel location and that stored for the second pixel location to said error threshold.
Claim 128
Dependent Claim
136 words
An inspection system for detecting anomalies on a surface, comprising: means for optically scanning the surface; means for collecting light scattered by the surface and deriving an intensity value for at least a first pixel location from the collected light; means for determining an error threshold for said at least first pixel location from intensity values stored for at least a corresponding second pixel location and its neighboring pixel locations of a reference image of the surface, said error threshold being determined by the difference between two intensity values stored for the second pixel location and its neighboring pixel locations in the reference image; and means for identifying anomalies by comparing the difference between the intensity value for the at least first pixel location and that stored for the second pixel location to said error threshold.
Claim 129
Dependent Claim
131 words
An inspection method for detecting anomalies on a surface, comprising the steps of: optically scanning the surface; collecting light scattered by the surface and deriving an intensity value for at least a first pixel location from the collected light; determining an error threshold for said at least first pixel location from intensity values stored for at least a corresponding second pixel location and its neighboring pixel locations of a reference image of the surface, said error threshold being determined by the difference between two intensity values stored for the second pixel location and its neighboring pixel locations in the reference image; and identifying anomalies by comparing the difference between the intensity value for the at least first pixel location and that stored for the second pixel location to said error threshold.
Claim 130
Dependent Claim
131 words
An inspection method for detecting anomalies on a surface, comprising the steps of: optically scanning the surface; collecting light scattered by the surface and deriving an intensity value for at least a first pixel location from the collected light; determining an error threshold for said at least first pixel location from intensity values stored for at least a corresponding second pixel location and its neighboring pixel locations of a reference image of the surface, said error threshold being determined by the difference between two intensity values stored for the second pixel location and its neighboring pixel locations in the reference image; and identifying anomalies by comparing the difference between the intensity value for the at least first pixel location and that stored for the second pixel location to said error threshold.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-01-25 | 2002-07-27 | 2003-01-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-01-25 | 2006-07-27 | 2007-01-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-01-25 | 2010-07-27 | 2011-01-26 | $7700.00 | Window Closed / Lapsed |