US4332477A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Flatness measuring apparatus
Assignee: Canon Inc
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Filing: 1980-12-11
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Granted: 1982-06-01
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Expires: 2000-12-11
Abstract
Abstract A flatness measuring apparatus or the like for measuring the flatness of a thin specimen such as a wafer for producing semi-conductor devices by detecting, with a photoreceptor, the first-order time-differentiated signal of the reflection angle of a laser scanning beam representing the surface configuration and electrically integrating said signal in time, said apparatus being featured in having a signal forming apparatus for providing, in case said thin specimen is inclined from a standard position, a correction signal corresponding to the amount of said inclination.
Inventors
- 👤 Masatoshi Sato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 20:32
CPC Classifications
G; G01; G01B; G01B11/00; G01B11/26; G01B11/30; G01B11/306
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
109 words
A flatness measuring apparatus, comprising: a scanning optical system for scanning a tested surface with a constant incident angle; a position detector for detecting the normal reflection angle from said tested surface; time-axis generating means for generating a square-wave output during a measuring time corresponding to the width of measurement; inclination signal generating means for generating a signal corresponding to the inclination of said tested surface with respect to a standard position thereof, and ratio calculating means for providing a ratio between the signal from said inclination signal generating means and a signal obtained by electrically integrating, with respect to time, the signal provided by said time-axis generating means.
Claim 2
Dependent Claim
109 words
A flatness measuring apparatus, comprising: a scanning optical system for scanning a tested surface with a constant incident angle; a position detector for detecting the normal reflection angle from said tested surface; time-axis generating means for generating a square-wave output during a measuring time corresponding to the width of measurement; inclination signal generating means for generating a signal corresponding to the inclination of said tested surface with respect to a standard position thereof, and ratio calculating means for providing a ratio between the signal from said inclination signal generating means and a signal obtained by electrically integrating, with respect to time, the signal provided by said time-axis generating means.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-05-31 | 1985-11-30 | 1986-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-05-31 | 1989-11-30 | 1990-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-05-31 | 1993-11-30 | 1994-06-01 | $7700.00 | Window Closed / Lapsed |