US4744713A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Misalignment sensor for a wafer feeder assembly
Assignee: Texas Instruments Inc
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Filing: 1986-05-21
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Granted: 1988-05-17
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Expires: 2006-05-21
Abstract
Abstract In an ion implantation device having a wafer holder assembly with a plurality of wafer holders each with a retractable wafer clamp and a wafer feeder for loading a wafer onto each wafer holder, there is provided a misalignment sensor which includes a light source for directing a collimated beam of light onto each wafer holder once a wafer has been loaded onto a corresponding wafer holder but before being clamped. A light sensor is coupled to the light souce for detecting light reflected at a predetermined angle from a loaded wafer. A display is provided for indicating misalignment of a wafer in response to the absence of reflected light being detected by the sensor at a predetermined time following loading.
Inventors
- 👤 Julius G. Hrovath
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 23:58
CPC Classifications
H; H10; H10P; H10P72/00; H10P72/50; H10P72/53; Y; Y10; Y10S; Y10S414/00; Y10S414/135; Y10S414/136; Y10S414/139
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
121 words
In an ion implantation device having a wafer holder assembly with a plurality of wafer holders each having a retractable wafer clamp and wafer feeder for loading wafers onto respective wafer holders, and a misalignment sensor, comprising: a light source for directing a collimated beam of light onto each wafer once a wafer has been loaded onto a corresponding wafer holder but before being clamped; a light sensor positioned relative to said light source for detecting light reflected from a loaded wafer at a predetermined angle from the direction of the incident beam of light; and means for indicating a misaligned wafer in response to the absence of reflected light being detected by said sensor within a predetermined time following loading.
Claim 2
Dependent Claim
121 words
In an ion implantation device having a wafer holder assembly with a plurality of wafer holders each having a retractable wafer clamp and wafer feeder for loading wafers onto respective wafer holders, and a misalignment sensor, comprising: a light source for directing a collimated beam of light onto each wafer once a wafer has been loaded onto a corresponding wafer holder but before being clamped; a light sensor positioned relative to said light source for detecting light reflected from a loaded wafer at a predetermined angle from the direction of the incident beam of light; and means for indicating a misaligned wafer in response to the absence of reflected light being detected by said sensor within a predetermined time following loading.
Claim 3
Dependent Claim
93 words
A sensor according to claim 1, wherein said indicating means includes a feed switch mounted on said wafer feeder to indicate when a feed arm thereof is extended corresponding to said feeder feeding a wafer onto said wafer holder, an actuator activated by the closing of said feed switch to close a first switch in parallel with said feed switch and by the detection of reflected light to open said first switch and close a second switch coupled to a processor which issues a signal indicating that a wafer has been correctly loaded.
Claim 4
Dependent Claim
39 words
A sensor according to claim 2, including a time delay relay in parallel with said actuator activated by the closing of said feed switch responsive to close a circuit containing an audio/visual alarm on the de-energizing of said actuator.
Claim 5
Dependent Claim
14 words
A sensor according to claim 2, wherein said light source is an infrared laser.
Claim 6
Dependent Claim
17 words
A sensor according to claim 2, wherein said feed arm switch and said first switch are microswitches.
Claim 7
Independent Claim
104 words
A method of detecting misloading of a wafer on a wafer holder of an ion implanter, comprising: directing a collimated beam of light onto a wafer loaded onto said wafer holder at said wafer holder's wafer loading position immediately following loading of a wafer thereon; detecting reflected light from a wafer loaded onto said wafer holder at a predetermined angle with respect to the direction of incidence of said collimated beam equal to twice the angle of incidence onto a properly loaded wafer mounted thereon; and means for indicating when reflected light is not detected following loading of a wafer onto a wafer holder.
Claim 8
Independent Claim
104 words
A method of detecting misloading of a wafer on a wafer holder of an ion implanter, comprising: directing a collimated beam of light onto a wafer loaded onto said wafer holder at said wafer holder's wafer loading position immediately following loading of a wafer thereon; detecting reflected light from a wafer loaded onto said wafer holder at a predetermined angle with respect to the direction of incidence of said collimated beam equal to twice the angle of incidence onto a properly loaded wafer mounted thereon; and means for indicating when reflected light is not detected following loading of a wafer onto a wafer holder.
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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) | 1991-05-17 | 1991-11-16 | 1992-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-17 | 1995-11-16 | 1996-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-17 | 1999-11-16 | 2000-05-17 | $7700.00 | Window Closed / Lapsed |