Patent US2314996A successfully refreshed from Google Patents.
US4454001A
Expired / Lapsed
US
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Interferometric method and apparatus for measuring etch rate and fabricating devices
Assignee: Nokia Bell Labs
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Filing: 1982-08-27
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Granted: 1984-06-12
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Expires: 2002-08-27
Abstract
Abstract A method and apparatus for measuring etch depth during the etching of a device pattern into a nontransparent substrate, is disclosed. The method makes use of the finding that the device patterns etched into substrates produce diffraction patterns when illuminated. Thus, according to the method, a beam of light is directed onto a region of a substrate, into which region a portion of a device pattern is being etched. The light reflected from this region forms a diffraction pattern and, according to the inventive method, the intensity of a diffraction order is detected and recorded as a function of time during the etching procedure. The intensity of the diffraction order varies with time. The etch rate of the substrate is inversely proportional to the period of the oscillations in the recorded intensity-time curve.
Inventors
- 👤 Marek A. Sternheim
- 👤 Willem van Gelder
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:14
CPC Classifications
G; G01; G01B; G01B11/00; G01B11/02; G01B11/06; G01B11/22
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
106 words
A method for fabricating a device, comprising the steps of: etching a pattern into a substrate; and monitoring said etching of said substrate by illuminating a region of said substrate with light and sensing a portion of the light reflected from said region, characterized in that said region of said substrate is a region into which a portion of said pattern is being etched, said sensing step includes the step of detecting the intensity of a diffraction order of the light reflected from said region, and said method further comprises the step of terminating said etching based on the detected number of cycles of said intensity.
Claim 2
Independent Claim
106 words
A method for fabricating a device, comprising the steps of: etching a pattern into a substrate; and monitoring said etching of said substrate by illuminating a region of said substrate with light and sensing a portion of the light reflected from said region, characterized in that said region of said substrate is a region into which a portion of said pattern is being etched, said sensing step includes the step of detecting the intensity of a diffraction order of the light reflected from said region, and said method further comprises the step of terminating said etching based on the detected number of cycles of said intensity.
Claim 3
Dependent Claim
13 words
The method of claim 1 wherein said substrate includes a patterned etch mask.
Claim 4
Dependent Claim
14 words
The method of claim 1 wherein said diffraction order is the zeroth diffraction order.
Claim 5
Dependent Claim
13 words
The method of claim 1 wherein said etching is produced by plasma etching.
Claim 6
Dependent Claim
14 words
The method of claim 1 wherein said etching is produced by reactive ion etching.
Claim 7
Dependent Claim
13 words
The method of claim 1 wherein said etching is produced by ion milling.
Claim 8
Dependent Claim
14 words
The method of claim 1 wherein said etching is produced by wet chemical etching.
Claim 9
Dependent Claim
16 words
The method of claim 1 wherein said etching is produced by a directed beam of energy.
Claim 10
Dependent Claim
17 words
The method of claim 1 wherein said etching is produced by a directed beam of charged particles.
Claim 11
Dependent Claim
21 words
The method of claim 1 further comprising the steps of performing the steps necessary to complete the fabrication of said device.
Claim 12
Independent Claim
109 words
A method for measuring the etch depth of a substrate during a process in which a device pattern is etched into said substrate, comprising the steps of: illuminating a region of said substrate with light; and sensing a portion of the light reflected from said region, characterized in that said region of said substrate is a region into which a portion of said pattern is being etched, said sensing step includes the step of detecting the intensity of a diffraction order of the light reflected from said region, and said method further comprises the step of terminating said etching based on the detected number of cycles of said intensity.
Claim 13
Independent Claim
109 words
A method for measuring the etch depth of a substrate during a process in which a device pattern is etched into said substrate, comprising the steps of: illuminating a region of said substrate with light; and sensing a portion of the light reflected from said region, characterized in that said region of said substrate is a region into which a portion of said pattern is being etched, said sensing step includes the step of detecting the intensity of a diffraction order of the light reflected from said region, and said method further comprises the step of terminating said etching based on the detected number of cycles of said intensity.
Claim 14
Dependent Claim
15 words
The method of claim 11 wherein said substrate is covered by a patterned etch mask.
Claim 15
Dependent Claim
13 words
The method of claim 11 wherein said diffraction order is the zeroth diffraction.
Claim 16
Dependent Claim
113 words
Apparatus for measuring the etch rate of a substrate, during a process in which a device pattern is etched into said substrate, comprising: first means for illuminating a region of said substrate with light; and second means for sensing a portion of the light reflected from said region, characterized in that said first means is adapted for directing light onto a region of said substrate into which a portion of said pattern is being etched, said second means includes means for detecting the intensity of a diffraction order of the light reflected from said region, and said etch rate is inversely proportional to a period of the variation with time of said intensity.
Claim 17
Dependent Claim
113 words
Apparatus for measuring the etch rate of a substrate, during a process in which a device pattern is etched into said substrate, comprising: first means for illuminating a region of said substrate with light; and second means for sensing a portion of the light reflected from said region, characterized in that said first means is adapted for directing light onto a region of said substrate into which a portion of said pattern is being etched, said second means includes means for detecting the intensity of a diffraction order of the light reflected from said region, and said etch rate is inversely proportional to a period of the variation with time of said intensity.
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) | 1987-06-12 | 1987-12-12 | 1988-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-06-12 | 1991-12-12 | 1992-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-06-12 | 1995-12-12 | 1996-06-12 | $7700.00 | Window Closed / Lapsed |