US4482424A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for monitoring etching of resists by monitoring the flouresence of the unetched material
Assignee: Nokia Bell Labs
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Filing: 1983-05-06
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Granted: 1984-11-13
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Expires: 2003-05-06
Abstract
Abstract A method for lithographically fabricating devices is disclosed. In accordance with the method, a sacrificial coating material (SCM), e.g., a resist, mixed with a fluorescent material is deposited onto a substrate and then etched. SCM etching is monitored by subjecting the fluorescent material within the SCM to fluorescence-inducing energy, and detecting the resulting fluorescence. Because the fluorescent material is etched away as the SCM is etched, fluorescence intensity decreases as SCM thickness is reduced. Thus, SCM etch end point is accurately determined because etch end point corresponds to the point in time when the detected fluorescence ceases.
Inventors
- 👤 Abraham Katzir
- 👤 Paul R. Kolodner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:14
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/62; G01N21/63; G01N21/64; H; H10; H10P; H10P95/00; G03; G03F; G03F7/00; G03F7/26; G03F7/30; G01N21/17; G01N21/25; G01N21/31; G01N21/314; G01N2021/3166; G01N2201/00; G01N2201/12; G01N2201/122; G01N2201/1222
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
82 words
A method for fabricating a device, said method comprising the steps of: forming a sacrificial coating material on a substrate; and etching at least a part of said material, Characterized In That said material includes fluorescent material, and said method further comprises the step of monitoring the etching of said sacrificial coating material by subjecting at least a portion of said part to a form of energy which induces unetched fluorescent material within said portion to fluoresce, and sensing the resulting fluorescence.
Claim 2
Independent Claim
82 words
A method for fabricating a device, said method comprising the steps of: forming a sacrificial coating material on a substrate; and etching at least a part of said material, Characterized In That said material includes fluorescent material, and said method further comprises the step of monitoring the etching of said sacrificial coating material by subjecting at least a portion of said part to a form of energy which induces unetched fluorescent material within said portion to fluoresce, and sensing the resulting fluorescence.
Claim 3
Dependent Claim
12 words
The method of claim 1 wherein said substrate includes a non-planar surface.
Claim 4
Dependent Claim
31 words
The method of claim 1 wherein said sacrificial coating material includes a first layer of material deposited onto said substrate, and a second layer of material deposited onto said first layer.
Claim 5
Dependent Claim
22 words
The method of claim 3 wherein said sacrificial coating material further includes a third layer of material deposited onto said second layer.
Claim 6
Dependent Claim
15 words
The method of claim 4 wherein said first layer of material includes said fluorescent material.
Claim 7
Dependent Claim
19 words
The method of claim 1 or claim 2 wherein said etching is discontinued when the sensed fluorescence substantially ceases.
Claim 8
Dependent Claim
38 words
The method of claim 5 wherein said etching step includes the steps of successively etching said third and second layers, the etching of said second layer being discontinued when the sensed fluorescence is first observed to substantially diminish.
Claim 9
Dependent Claim
33 words
The method of claim 5 or 7 wherein said etching step includes the step of etching said first layer, the etching of said first layer being discontinued when the sensed fluorescence substantially ceases.
Claim 10
Dependent Claim
40 words
The method of claim 6 wherein the detected time of cessation of said fluorescence differs from the true etch end point of said sacrificial coating material by an equivalent thickness of said sacrificial coating material less than about 100 Angstroms.
Claim 11
Dependent Claim
40 words
The method of claim 6 wherein the detected time of cessation of said fluorescence differs from the true etch end point of said sacrificial coating material by an equivalent thickness of said sacrificial coating material less than about 10 Angstroms.
Claim 12
Dependent Claim
38 words
The method of claim 8 wherein the detected time of cessation of said fluorescence differs from the true etch end point of said first layer by an equivalent thickness of said first layer less than about 100 Angstroms.
Claim 13
Dependent Claim
38 words
The method of claim 8 wherein the detected time of cessation of said fluorescence differs from the true etch end point of said first layer by an equivalent thickness of said first layer less than about 10 Angstroms.
Claim 14
Dependent Claim
23 words
The method of claim 1 wherein the concentration of said fluorescent material in said sacrificial coating material is greater than about 0.001 percent.
Claim 15
Dependent Claim
24 words
The method of claim 1 wherein the quantum efficiency of said fluorescent material, in said sacrificial coating material, is greater than about 0.01 percent.
Claim 16
Dependent Claim
27 words
The method of claim 1 wherein said sacrificial coating material absorbs more than about 0.01 percent, but less than about 50 percent, of the incident fluorescence-inducing energy.
Claim 17
Dependent Claim
11 words
The method of claim 1 wherein said fluorescent material includes 4-dicyanomethylene-2-methyl-6-p-diethylaminostyryl-4H-pyran.
References Cited (Backward Citations)
US4244799A
Cited
US4246060A
Cited
US4377436A
Cited
JPS5726438A
Cited
JPS5747874A
Cited
EP0062302A2
Cited
US4415402A
Cited
US4394237A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-11-13 | 1988-05-14 | 1988-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-11-13 | 1992-05-14 | 1992-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-11-13 | 1996-05-14 | 1996-11-13 | $7700.00 | Window Closed / Lapsed |