US3737237A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Monitoring deposition of films
Assignee: National Aeronautics and Space Administration
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Filing: 1971-11-18
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Granted: 1973-06-05
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Expires: 1991-11-18
Abstract
Abstract A system using dual wavelength characteristics of light passing through a film being deposited to generate an output signal that changes rapidly at the point when the deposition process should stop or change. Photodetectors are used to sense the light intensity changes at the two wavelengths and the monitored signal represents the ratio of their sums and difference signal strengths.
Inventors
- 👤 J Zurasky
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 07:11
CPC Classifications
G; G01; G01B; G01B11/00; G01B11/02; G01B11/06; G01B11/0616; G01B11/0625; G01B11/0633
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
177 words
A monitor for determining the thickness of a thin film being deposited, comprising: a light source which directs a light beam so it will be incident on the film being deposited, a dichroic filter to split the resulting light beam acted upon by said film so that said resulting light beam is divided into two branch light beams of differing wavelengths, a first filter of a known light transmission wavelength acting upon one of said branch light beams, a second filter of a known light transmission wavelength acting upon the other of said branch light beams, a first means for producing an electrical signal representative of the intensity of light transmitted by said first filter, a second means for producing an electrical signal representative of the intensity of light transmitted by said second filter, a readout device which receives said electrical signals of said first and second means and gives a ratio readout of the sum and difference of said electrical signals which readout changes rapidly at the point where film deposition must be stopped or changed.
Claim 2
Dependent Claim
177 words
A monitor for determining the thickness of a thin film being deposited, comprising: a light source which directs a light beam so it will be incident on the film being deposited, a dichroic filter to split the resulting light beam acted upon by said film so that said resulting light beam is divided into two branch light beams of differing wavelengths, a first filter of a known light transmission wavelength acting upon one of said branch light beams, a second filter of a known light transmission wavelength acting upon the other of said branch light beams, a first means for producing an electrical signal representative of the intensity of light transmitted by said first filter, a second means for producing an electrical signal representative of the intensity of light transmitted by said second filter, a readout device which receives said electrical signals of said first and second means and gives a ratio readout of the sum and difference of said electrical signals which readout changes rapidly at the point where film deposition must be stopped or changed.
Claim 3
Dependent Claim
16 words
A monitor according to claim 1 wherein: said light source projects a collimated modulated light beam.
Claim 4
Dependent Claim
188 words
A monitor for deposition of thin films in an evaporation chamber, comprising: a light source which directs a collimated light beam into said evaporation chamber so said light beam will be incident on the thin film being deposited, a mirrow device for reflecting the resulting light beam acted upon by said film into a dichroic filter so that said resulting beam is divided into two branch light beams, one of the branch light beams being directed through a first filter of a known transmission wavelength, and the other of said branch light beams being directed through a second filter of a slightly different transmission wavelength, a first photodetector means for producing an electrical signal representative of the light transmitted by said first filter, a second photodector means for producing an electrical signal representative of the light transmitted by said second filter, and an amplifier and readout device for receiving said electrical signals from said first and second photodetectors for giving a ratio readout of the sum and difference between said two electrical signals which readout rapidly changes at the point where film deposition must be stopped or changed.
Claim 5
Dependent Claim
188 words
A monitor for deposition of thin films in an evaporation chamber, comprising: a light source which directs a collimated light beam into said evaporation chamber so said light beam will be incident on the thin film being deposited, a mirrow device for reflecting the resulting light beam acted upon by said film into a dichroic filter so that said resulting beam is divided into two branch light beams, one of the branch light beams being directed through a first filter of a known transmission wavelength, and the other of said branch light beams being directed through a second filter of a slightly different transmission wavelength, a first photodetector means for producing an electrical signal representative of the light transmitted by said first filter, a second photodector means for producing an electrical signal representative of the light transmitted by said second filter, and an amplifier and readout device for receiving said electrical signals from said first and second photodetectors for giving a ratio readout of the sum and difference between said two electrical signals which readout rapidly changes at the point where film deposition must be stopped or changed.
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) | 1976-06-04 | 1976-12-04 | 1977-06-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-04 | 1980-12-04 | 1981-06-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-04 | 1984-12-04 | 1985-06-05 | $7700.00 | Window Closed / Lapsed |