US5532499A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Beam spot position detector having a detector moving mechanism
Assignee: Applejack 199 LP
•
Filing: 1994-10-03
•
Granted: 1996-07-02
•
Expires: 2014-10-03
Abstract
Abstract A method for measuring surface topography characterized by making multiple scans of the surface with a laser scanning unit and utilizing the multiple scans to create representations of the surface's topography. The surface topography data can also be used to calculate the compressive or tensile stress caused by a thin film applied to the surface of a semiconductor wafer. The apparatus of the present invention scans a laser beam across a surface in an x direction, and detects displacements of a reflected portion of the laser beam in a z direction. A pair of photodetectors are used to translate z direction displacements of the reflected beam into analog signals which are digitized and input into a microcomputer for analysis. The multiple scans of the surface are preferably accomplished by placing the workpiece on a pedestal which can be rotated to various angular positions.
Inventors
- 👤 David Cheng
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 10:19
CPC Classifications
H; H10; H10P; H10P72/00; H10P72/06; H10P72/0616; G; G01; G01B; G01B11/00; G01B11/16; G01B11/24; G01B11/255; G01B11/30; G01B11/306
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
240 words
A beam spot position detector assembly comprising: a first photodetector having a first substantially planar photosensitive surface and operative to develop a first signal in response to a spot from a beam of radiant energy which impinges upon at least part of said first photosensitive surface; a second photo detector having a second substantially planar photosensitive surface and operative to develop a second signal in response to said spot which impinges upon at least part of said second photosensitive surface, said first photosensitive surface and said second photosensitive surface being substantially coplanar and abutting along an elongated, linear interface; processing means coupled to said first photodetector and said second photodetector and responsive to said first signal and said second signal and operative to develop a beam spot position signal representative of the position of said beam spot relative to said linear interface; means for moving said first photodetector and said second photodetector in a direction parallel to their planar surfaces and perpendicular to said linear interface; and means for maintaining a beam spot within a linear region of said first photodetector and said second photodetector by controlling said moving means to maintain said beam spot within a linear region distance of said linear interface, said linear region distance being a distance from said linear interface wherein said beam spot position signal changes generally linearly with changes in displacement of said beam spot in said direction perpendicular to said linear interface.
Claim 2
Dependent Claim
240 words
A beam spot position detector assembly comprising: a first photodetector having a first substantially planar photosensitive surface and operative to develop a first signal in response to a spot from a beam of radiant energy which impinges upon at least part of said first photosensitive surface; a second photo detector having a second substantially planar photosensitive surface and operative to develop a second signal in response to said spot which impinges upon at least part of said second photosensitive surface, said first photosensitive surface and said second photosensitive surface being substantially coplanar and abutting along an elongated, linear interface; processing means coupled to said first photodetector and said second photodetector and responsive to said first signal and said second signal and operative to develop a beam spot position signal representative of the position of said beam spot relative to said linear interface; means for moving said first photodetector and said second photodetector in a direction parallel to their planar surfaces and perpendicular to said linear interface; and means for maintaining a beam spot within a linear region of said first photodetector and said second photodetector by controlling said moving means to maintain said beam spot within a linear region distance of said linear interface, said linear region distance being a distance from said linear interface wherein said beam spot position signal changes generally linearly with changes in displacement of said beam spot in said direction perpendicular to said linear interface.
Claim 3
Dependent Claim
29 words
A beam spot position detector as recited in claim 1 wherein said processing means comprises means for obtaining a difference signal from said first signal and said second signal.
Claim 4
Dependent Claim
30 words
A beam spot position detector as recited in claim 2 wherein said processing means further comprises means for obtaining a sum signal from said first signal and said second signal.
Claim 5
Dependent Claim
31 words
A beam spot position detector as recited in claim 3 wherein said processing means further comprises means for obtaining a normalized signal by dividing said difference signal by said sum signal.
Claim 6
Dependent Claim
50 words
A beam spot position detector as recited in claim 4 wherein said linear region distance is about ten percent of the distance from said linear interface to a point on said planar surfaces of said first and second photodetectors where said beam spot is located just outside said linear interface.
Claim 7
Dependent Claim
19 words
A beam spot position detector as recited in claim 5 wherein said linear region distance is about 0.01 millimeters.
Claim 8
Independent Claim
240 words
An apparatus for detecting a position of a beam spot, comprising: a first photodetector having a first substantially planar photosensitive surface and operative to develop a first signal in response to a spot from a beam of radiant energy which impinges upon at least part of said first photosensitive surface; a second photodetector having a second substantially planar photosensitive surface and operative to develop a second signal in response to said spot which impinges upon at least part of said second photosensitive surface, said first photosensitive surface and said second photosensitive surface being substantially coplanar and abutting along an elongated, linear interface; a processor coupled to said first photodetector and said second photodetector and responsive to said first signal and said second signal and operative to develop a beam spot position signal representative of the position of said beam spot relative to said linear interface: a translater for translating said first photodetector and said second photodetector in a direction parallel to their planar surfaces and perpendicular to said linear interface; and a controller for maintaining a beam spot within a linear region of said first photodetector and said second photodetector by controlling said translater to maintain said beam spot within a linear region distance of said linear interface, said linear region distance being a distance from said linear interface wherein said beam spot position signal changes generally linearly with changes in displacment in said direction perpendicular to said linear interface.
Claim 9
Independent Claim
240 words
An apparatus for detecting a position of a beam spot, comprising: a first photodetector having a first substantially planar photosensitive surface and operative to develop a first signal in response to a spot from a beam of radiant energy which impinges upon at least part of said first photosensitive surface; a second photodetector having a second substantially planar photosensitive surface and operative to develop a second signal in response to said spot which impinges upon at least part of said second photosensitive surface, said first photosensitive surface and said second photosensitive surface being substantially coplanar and abutting along an elongated, linear interface; a processor coupled to said first photodetector and said second photodetector and responsive to said first signal and said second signal and operative to develop a beam spot position signal representative of the position of said beam spot relative to said linear interface: a translater for translating said first photodetector and said second photodetector in a direction parallel to their planar surfaces and perpendicular to said linear interface; and a controller for maintaining a beam spot within a linear region of said first photodetector and said second photodetector by controlling said translater to maintain said beam spot within a linear region distance of said linear interface, said linear region distance being a distance from said linear interface wherein said beam spot position signal changes generally linearly with changes in displacment in said direction perpendicular to said linear interface.
Claim 10
Dependent Claim
47 words
An apparatus as recited in claim 7 wherein said linear region distance is about ten percent of the distance from said linear interface to a point on said planar surfaces of said first and second photodetectors where said beam spot is located just outside said linear interface.
Claim 11
Dependent Claim
16 words
An apparatus as recited in claim 8 wherein said linear region distance is about 0.01 millimeters.
Claim 12
Dependent Claim
26 words
An apparatus as recited in claim 7 wherein said processor comprises a mechanism for obtaining a difference signal from said first signal and said second signal.
Claim 13
Dependent Claim
27 words
An apparatus as recited in claim 10 wherein said processor further comprises a mechanism for obtaining a sum signal from said first signal and said second signal.
Claim 14
Dependent Claim
28 words
An apparatus as recited in claim 11 wherein said processor further comprises a mechanism for obtaining a normalized signal by dividing said difference signal by said sum signal.
Claim 15
Independent Claim
215 words
A method for detecting a position of a beam spot comprising the steps of: developing a first signal in response to a spot from a beam of radiant energy which impinges upon at least part of a first substantially planar photosensitive surface of a first photodetector; developing a second signal in response to said spot which impinges upon at least part of a second substantially planar photosensitive surface of a second photodetector, said first photosensitive surface and said second photosensitive surface being substantially coplanar and abutting along an elongated, linear interface; developing a beam spot position signal representative of the position of said beam spot relative to said linear interface in response to receiving said first signal and said second signal; and maintaining a beam spot within a linear region of said first photodetector and said second photodetector by controlling a translater to maintain said beam spot within a linear region distance of said linear interface, said translater being operative to translate said first photodetector and said second photodetector in a direction parallel to their planar surfaces and perpendicular to the linear interface, said linear region distance being a distance from said linear interface wherein said beam spot position signal changes generally linearly with changes in displacment in said direction perpendicular to said linear interface.
Claim 16
Independent Claim
215 words
A method for detecting a position of a beam spot comprising the steps of: developing a first signal in response to a spot from a beam of radiant energy which impinges upon at least part of a first substantially planar photosensitive surface of a first photodetector; developing a second signal in response to said spot which impinges upon at least part of a second substantially planar photosensitive surface of a second photodetector, said first photosensitive surface and said second photosensitive surface being substantially coplanar and abutting along an elongated, linear interface; developing a beam spot position signal representative of the position of said beam spot relative to said linear interface in response to receiving said first signal and said second signal; and maintaining a beam spot within a linear region of said first photodetector and said second photodetector by controlling a translater to maintain said beam spot within a linear region distance of said linear interface, said translater being operative to translate said first photodetector and said second photodetector in a direction parallel to their planar surfaces and perpendicular to the linear interface, said linear region distance being a distance from said linear interface wherein said beam spot position signal changes generally linearly with changes in displacment in said direction perpendicular to said linear interface.
Claim 17
Dependent Claim
47 words
A method as recited in claim 13 wherein said linear region distance is about ten percent of the distance from said linear interface to a point on said planar surfaces of said first and second photodetectors where said beam spot is located just outside said linear interface.
Claim 18
Dependent Claim
16 words
A method as recited in claim 14 wherein said linear region distance is about 0.01 millimeters.
Claim 19
Dependent Claim
29 words
A method as recited in claim 13 wherein said step of developing a beam spot signal includes obtaining a difference signal from said first signal and said second signal.
Claim 20
Dependent Claim
29 words
A method as recited in claim 16 wherein said step of developing a beam spot signal includes obtaining a sum signal from said first signal and said second signal.
Claim 21
Dependent Claim
30 words
A method as recited in claim 17 wherein said step of developing a beam spot signal includes obtaining a normalized signal by dividing said difference signal by said sum signal.
References Cited (Backward Citations)
US3406292A
Cited
US3679307A
Cited
US4145140A
Cited
US4386272A
Cited
US4386272C1
Cited
US4297034A
Cited
US4506149A
Cited
US4672196A
Cited
US4815857A
Cited
US4788421A
Cited
US4667113A
Cited
US5162642A
Cited
US4900940A
Cited
US5134303A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-07-02 | 2000-01-01 | 2000-07-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-07-02 | 2004-01-01 | 2004-07-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-07-02 | 2008-01-01 | 2008-07-02 | $7700.00 | Window Closed / Lapsed |