US5381004A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Particle analysis of notched wafers
Assignee: Applied Materials Inc
•
Filing: 1993-08-31
•
Granted: 1995-01-10
•
Expires: 2013-08-31
Abstract
Abstract A method for reducing targeting errors that arise when trying to locate contaminant particles on a notched semiconductor wafer using a high-magnification imaging device, based on estimates of wafer feature positions obtained from a scanning device. The present invention scans a notched semiconductor wafer with a scanning device to obtain scanning device coordinates for the positions of: (i) the wafer center; (ii) the wafer notch; and (iii) contaminant particles on the wafer. Next, the present invention finds the wafer notch and wafer center with an imaging device and obtains their estimated imaging device coordinates. Subsequently, the present invention calculates estimated transformation parameters for a coordinate transformation between the coordinate systems of the scanning device and the imaging device based on the scamping device coordinates and the estimated imaging device coordinates of the wafer notch and the wafer center. Finally, the present invention transforms the scanning device coordinates of the particles on the wafer to estimated imaging device coordinates using the estimated transformation parameters.
Inventors
- 👤 Yuri S. Uritsky
- 👤 Harry Q. Lee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 18:50
CPC Classifications
H; H10; H10P; H10P74/00; H10P74/23; G; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/8851; H01; H01J; H01J37/00; H01J37/252; H01J37/256; H10W; H10W46/00; H10W46/201; H10P74/20; H10P74/203; H10W46/501
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
146 words
A method for locating particles on a notched semiconductor wafer, the method comprising: (a) scanning a notched semiconductor wafer with a scanning device to obtain scanning device coordinates pertaining to the positions of: (i) the center of the wafer, (ii) the wafer notch, and (iii) contaminant particles on the wafer; (b) finding the wafer notch with an imaging device and obtaining its estimated imaging device coordinates; (c) finding the wafer center with an imaging device and obtaining its estimated imaging device coordinates; (d) calculating estimated transformation parameters for a coordinate transformation between the coordinate systems of the scanning device and the imaging device based on the scanning device coordinates and the estimated imaging device coordinates of the wafer notch and the wafer center; and (e) transforming the scanning device coordinates of the particles on the wafer to estimated imaging device coordinates using the estimated transformation parameters.
Claim 2
Independent Claim
146 words
A method for locating particles on a notched semiconductor wafer, the method comprising: (a) scanning a notched semiconductor wafer with a scanning device to obtain scanning device coordinates pertaining to the positions of: (i) the center of the wafer, (ii) the wafer notch, and (iii) contaminant particles on the wafer; (b) finding the wafer notch with an imaging device and obtaining its estimated imaging device coordinates; (c) finding the wafer center with an imaging device and obtaining its estimated imaging device coordinates; (d) calculating estimated transformation parameters for a coordinate transformation between the coordinate systems of the scanning device and the imaging device based on the scanning device coordinates and the estimated imaging device coordinates of the wafer notch and the wafer center; and (e) transforming the scanning device coordinates of the particles on the wafer to estimated imaging device coordinates using the estimated transformation parameters.
Claim 3
Dependent Claim
28 words
A method as defined in claim 1, wherein: the wafer notch is positioned in a laser scanning device specimen holder in predetermined orientation prior to scanning the wafer.
Claim 4
Dependent Claim
40 words
A method as defined in claim 2, wherein: the wafer notch is positioned in a laser scanning device specimen holder with the notch point at an angle of approximately 120 degrees from a predetermined axis prior to scanning the wafer.
Claim 5
Dependent Claim
21 words
A method as defined in claim 1, further comprising: loading the wafer on an image scanning device in a predetermined orientation.
Claim 6
Dependent Claim
32 words
A method as defined in claim 4, wherein the wafer is loaded on an image scanning device with the notch point at an angle of approximately 45 degrees from a predetermined axis.
Claim 7
Dependent Claim
44 words
A method as defined in claim 1, wherein the step of calculating estimated transformation parameters is also based upon an estimated angle of rotation determined from the scanning device coordinates and the estimated imaging device coordinates of the wafer notch and the wafer center.
Claim 8
Dependent Claim
43 words
A method as defined in claim 1, wherein the step of finding the wafer notch with an imaging device and obtaining its estimated imaging device coordinates includes: finding the imaging device coordinates of the intersection of two straight lines along the notch perimeter.
Claim 9
Dependent Claim
64 words
A method as defined in claim 1, wherein the step of finding the wafer notch with an imaging device and obtaining its estimated imaging device coordinates includes: locating points along the circumference of the notch and determining the imaging device coordinates of the center of the notch curvature using a least squares fit based upon the imaging device coordinates of the notch circumference points.
Claim 10
Dependent Claim
21 words
A method as defined in claim 8, wherein the number of points located along the circumference of the notch is four.
Claim 11
Dependent Claim
108 words
A method as defined in claim 1, wherein the step of finding the wafer notch with an imaging device and obtaining its estimated imaging device coordinates includes: finding the imaging device coordinates of the intersection of two straight lines along the notch perimeter; locating points along the circumference of the notch; determining the imaging device coordinates of the center of the notch curvature using a least squares fit based upon the coordinates of the notch circumference points; and averaging (i) the imaging device coordinates of the intersection of two straight lines along the notch perimeter, and (ii) the imaging device coordinates of the center of the notch curvature.
Claim 12
Dependent Claim
57 words
A method as defined in claim 1, wherein the step of finding the wafer center with an imaging device and obtaining its estimated imaging device coordinates includes: locating at least three points on the circumference of the wafer and determining the imaging device coordinates of the intersection of perpendicular bisectors of chords drawn between adjacent circumference points.
Claim 13
Dependent Claim
76 words
A method as defined in claim 1, wherein the step of finding the wafer center with an imaging device and obtaining its estimated imaging device coordinates includes: locating four points on the circumference of the wafer; for each unique combination of three points, determining the imaging device coordinates of the intersection of perpendicular bisectors of chords drawn between adjacent circumference points; and averaging the intersection imaging device coordinates determined for each unique combination of three points.
Claim 14
Dependent Claim
63 words
A method as defined in claim 1, wherein the step of finding the wafer center with an imaging device and obtaining its estimated imaging device coordinates includes: locating at least three points on the circumference of the wafer and determining the imaging device coordinates of the center of the points using a least squares fit based upon the coordinates of the circumference points.
Claim 15
Dependent Claim
56 words
A method as defined in claim 1, wherein the step finding the wafer center with an imaging device and obtaining its estimated imaging device coordinates includes: locating at least two points on the circumference of the wafer and determining the imaging device coordinates of the intersection of lines drawn perpendicular to tangents of the circumference points.
Claim 16
Dependent Claim
170 words
A method as defined in claim 1, wherein the step of finding the wafer center an the imaging device and obtaining its estimated imaging device coordinates includes: locating at least three points on the circumference of the wafer and determining the imaging device coordinates of the intersection of perpendicular bisectors of chords drawn between adjacent circumference points; locating at least three points on the circumference of the wafer and determining the imaging device coordinates of the center of the points using a least squares fit based upon the coordinates of the circumference points; locating at least two points on the circumference of the wafer and determining the imaging device coordinates of the intersection of lines drawn perpendicular to tangents of the circumference points; and averaging the imaging device coordinates of the intersection of perpendicular bisectors of chords drawn between adjacent circumference points, the imaging device coordinates of the center of the points, and the imaging device coordinates of the intersection of lines drawn perpendicular to tangents of the circumference points.
Claim 17
Dependent Claim
93 words
A method as defined in claim 1, further comprising: (f) finding at least two reference particles with an imaging device using their estimated imaging device coordinates and obtaining their actual imaging device coordinates; (g) calculating actual transformation parameters for a coordinate transformation between the coordinate systems of the scanning device and the imaging device based on the scanning device coordinates and the actual imaging device coordinates of the reference particles; and (h) transforming the scanning device coordinates of the remaining particles on the wafer to imaging device coordinates using the actual transformation parameters.
Claim 18
Dependent Claim
36 words
A method as defined in claim 16, wherein the step of calculating actual transformation parameters includes inverse mapping the actual imaging device coordinates of the reference particles to the scanning device coordinates of the reference particles.
Claim 19
Dependent Claim
101 words
A method as defined in claim 16, wherein the step of calculating actual transformation parameters further includes: determining an actual angle of rotation based on the scanning device coordinates of the reference particles and the actual imaging device coordinates of the reference particles; determining actual imaging device coordinates of the wafer center based on the scanning device coordinates of the wafer center, the actual imaging device coordinates of the reference particles, and the actual angle of rotation; and using the actual angle of rotation and using the actual imaging device coordinates of the wafer center to determine the actual transformation parameters.
Claim 20
Independent Claim
322 words
A method for locating particles on a notched semiconductor wafer, the method comprising: (a) scanning a notched semiconductor wafer with a scanning device to obtain scanning device coordinates pertaining to the positions of: (i) the center of the wafer, (ii) the wafer notch, and (iii) contaminant particles on the wafer; (b) finding the wafer notch with an imaging device and obtaining its estimated imaging device coordinates; (c) finding the wafer center with an imaging device and obtaining its estimated imaging device coordinates; (d) determining an estimated angle of rotation based on the estimated imaging device coordinates of the wafer notch and the wafer center; (e) calculating estimated transformation parameters for a coordinate transformation between the coordinate systems of the scanning device and the imaging device based on the scanning device coordinates and the estimated imaging device coordinates of the wafer notch and the wafer center, and based on the estimated angle of rotation; (f) transforming the scanning device coordinates of the particles on the wafer to estimated imaging device coordinates using the estimated transformation parameters; (g) finding at least two reference particles with an imaging device using their estimated imaging device coordinates and obtaining their actual imaging device coordinates; (h) determining an actual angle of rotation based on scanning device coordinates of the reference particles and the actual imaging device coordinates of the reference particles; (i) determining actual imaging device coordinates of the wafer center based on the scanning device coordinates of the wafer center, the actual imaging device coordinates of the reference particles, and the actual angle of rotation; (j) calculating actual transformation parameters for a coordinate transformation between the coordinate systems of the scanning device and the imaging device based on the actual angle of rotation and using the actual imaging device coordinates of the wafer center; and (k) transforming the scanning device coordinates of the remaining particles on the wafer to imaging device coordinates using the actual transformation parameters.
Claim 21
Independent Claim
322 words
A method for locating particles on a notched semiconductor wafer, the method comprising: (a) scanning a notched semiconductor wafer with a scanning device to obtain scanning device coordinates pertaining to the positions of: (i) the center of the wafer, (ii) the wafer notch, and (iii) contaminant particles on the wafer; (b) finding the wafer notch with an imaging device and obtaining its estimated imaging device coordinates; (c) finding the wafer center with an imaging device and obtaining its estimated imaging device coordinates; (d) determining an estimated angle of rotation based on the estimated imaging device coordinates of the wafer notch and the wafer center; (e) calculating estimated transformation parameters for a coordinate transformation between the coordinate systems of the scanning device and the imaging device based on the scanning device coordinates and the estimated imaging device coordinates of the wafer notch and the wafer center, and based on the estimated angle of rotation; (f) transforming the scanning device coordinates of the particles on the wafer to estimated imaging device coordinates using the estimated transformation parameters; (g) finding at least two reference particles with an imaging device using their estimated imaging device coordinates and obtaining their actual imaging device coordinates; (h) determining an actual angle of rotation based on scanning device coordinates of the reference particles and the actual imaging device coordinates of the reference particles; (i) determining actual imaging device coordinates of the wafer center based on the scanning device coordinates of the wafer center, the actual imaging device coordinates of the reference particles, and the actual angle of rotation; (j) calculating actual transformation parameters for a coordinate transformation between the coordinate systems of the scanning device and the imaging device based on the actual angle of rotation and using the actual imaging device coordinates of the wafer center; and (k) transforming the scanning device coordinates of the remaining particles on the wafer to imaging device coordinates using the actual transformation parameters.
Claim 22
Dependent Claim
184 words
A method as defined in claim 19, further comprising: repeating steps (a) through (k) to process additional wafers; for each wafer, determining an error in the estimated angle of rotation based on the difference between the estimated angle of rotation and the actual angle of rotation; for each wafer, determining an error in the estimated imaging device coordinates of the wafer center based on the difference between the estimated imaging device coordinates of the wafer center and the actual imaging device coordinates of the wafer center; averaging the error in the estimated angle of rotation of the processed wafers to obtain an average rotation error; averaging the error in the estimated imaging device coordinates of the wafer center of the processed wafers to obtain an average center error; wherein each step (h) of determining an actual angle of rotation further includes correcting the actual angle of rotation using the average rotation error; and wherein each step (i) of determining actual imaging device coordinates of the wafer center further includes correcting the actual imaging device coordinates of the wafer center using the average center error.
Claim 23
Independent Claim
287 words
A method for locating particles on a notched semiconductor wafer, the method comprising: (a) scanning a notched semiconductor wafer with a scanning device to obtain scanning device coordinates pertaining to the positions of: (i) the center of the wafer, (ii) the wafer notch, and (iii) contaminant particles on the wafer; (b) loading the wafer on an image scanning device in a predetermined orientation; (c) finding the wafer notch with an imaging device; (d) obtaining the wafer notch estimated imaging device coordinates by finding the imaging device coordinates of the intersection of two straight lines along the notch perimeter; (e) determining the estimated imaging device coordinates of the wafer center by locating at least three points on the circumference of the wafer and determining the imaging device coordinates of the intersection of perpendicular bisectors of chords drawn between adjacent circumference points; (f) calculating estimated transformation parameters for a coordinate transformation between the coordinate systems of the scanning device and the imaging device based on the scanning device coordinates and the estimated imaging device coordinates of the wafer notch and the wafer center; (g) transforming the scanning device coordinates of the particles on the wafer to estimated imaging device coordinates using the estimated transformation parameters; (h) finding at least two reference particles with an imaging device using their estimated imaging device coordinates and obtaining their actual imaging device coordinates; (i) calculating actual transformation parameters for a coordinate transformation between the coordinate systems of the scanning device and the imaging device based on the scanning device coordinates and the actual imaging device coordinates of the reference particles; and (j) transforming the scanning device coordinates of the remaining particles on the wafer to imaging device coordinates using the actual transformation parameters.
Claim 24
Independent Claim
287 words
A method for locating particles on a notched semiconductor wafer, the method comprising: (a) scanning a notched semiconductor wafer with a scanning device to obtain scanning device coordinates pertaining to the positions of: (i) the center of the wafer, (ii) the wafer notch, and (iii) contaminant particles on the wafer; (b) loading the wafer on an image scanning device in a predetermined orientation; (c) finding the wafer notch with an imaging device; (d) obtaining the wafer notch estimated imaging device coordinates by finding the imaging device coordinates of the intersection of two straight lines along the notch perimeter; (e) determining the estimated imaging device coordinates of the wafer center by locating at least three points on the circumference of the wafer and determining the imaging device coordinates of the intersection of perpendicular bisectors of chords drawn between adjacent circumference points; (f) calculating estimated transformation parameters for a coordinate transformation between the coordinate systems of the scanning device and the imaging device based on the scanning device coordinates and the estimated imaging device coordinates of the wafer notch and the wafer center; (g) transforming the scanning device coordinates of the particles on the wafer to estimated imaging device coordinates using the estimated transformation parameters; (h) finding at least two reference particles with an imaging device using their estimated imaging device coordinates and obtaining their actual imaging device coordinates; (i) calculating actual transformation parameters for a coordinate transformation between the coordinate systems of the scanning device and the imaging device based on the scanning device coordinates and the actual imaging device coordinates of the reference particles; and (j) transforming the scanning device coordinates of the remaining particles on the wafer to imaging device coordinates using the actual transformation parameters.
References Cited (Backward Citations)
US4037941A
Cited
US4611292A
Cited
US4659220A
Cited
US4878247A
Cited
US4900695A
Cited
US5267017A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-01-09 | 1998-07-11 | 1999-01-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-01-09 | 2002-07-11 | 2003-01-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-01-09 | 2006-07-11 | 2007-01-10 | $7700.00 | Window Closed / Lapsed |