US4548688A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hardening of photoresist
Assignee: Tokyo Electron Ltd
•
Filing: 1983-05-23
•
Granted: 1985-10-22
•
Expires: 2003-05-23
Abstract
Abstract Photoresist is hardened by exposing it to UV radiation while subjecting it to elevated temperatures upon an increase in the degree of polymerization due to exposure to the radiation. The temperature of the photoresist can be controlled by a thermal chuck which contains a thermal ballast of heat conducting material.
Inventors
- 👤 John C. Matthews
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:16
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/20; G03F7/2022; G03F7/2024
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
124 words
A method of hardening a positive photoresist which comprises exposing a film of positive photoresist material to UV radiation containing sufficient dosage of wavelengths of about 320 nm or below to cause said photoresist to harden while subjecting the film to elevated temperature upon increase in the degree of polymerization due to exposure to said UV radiation wherein said elevated temperature, at any instant during the said exposing, is below the flow temperature of the film at the particular instant, and wherein the resist is subjected to elevated temperature during the exposure to the UV radiation which is greater than the initial flow temperature of the resist at the start of the exposure to the UV radiation, and to thereby harden said positive photoresist.
Claim 2
Independent Claim
124 words
A method of hardening a positive photoresist which comprises exposing a film of positive photoresist material to UV radiation containing sufficient dosage of wavelengths of about 320 nm or below to cause said photoresist to harden while subjecting the film to elevated temperature upon increase in the degree of polymerization due to exposure to said UV radiation wherein said elevated temperature, at any instant during the said exposing, is below the flow temperature of the film at the particular instant, and wherein the resist is subjected to elevated temperature during the exposure to the UV radiation which is greater than the initial flow temperature of the resist at the start of the exposure to the UV radiation, and to thereby harden said positive photoresist.
Claim 3
Dependent Claim
15 words
The method of claim 1 wherein said UV radiation contains wavelengths of about 180-320 nm.
Claim 4
Dependent Claim
15 words
The method of claim 1 wherein said UV radiation has wavelengths of about 190-260 nm.
Claim 5
Dependent Claim
14 words
The method of claim 1 wherein said elevated temperature is above about 100° C.
Claim 6
Dependent Claim
14 words
The method of claim 1 wherein said photoresist is a diazo sensitized polymer composition.
Claim 7
Dependent Claim
13 words
The method of claim 5 wherein said polymer is a phenolic-formaldehyde novalak type.
Claim 8
Dependent Claim
14 words
The method of claim 1 wherein said elevated temperature is above about 120° C.
Claim 9
Dependent Claim
17 words
The method of claim 1 wherein the photoresist is heated to elevated temperature of about 200° C.
Claim 10
Dependent Claim
19 words
The method of claim 1 wherein the film of positive photoresist material is about 10,000 to about 20,000 angstroms.
Claim 11
Dependent Claim
48 words
The method of claim 1 which further comprises controlling the temperature of the photoresist during the exposure to radiation so that it rises at approximately the same rate as does the flow temperature while insuring that the temperature of the photoresist never equals or exceeds the flow temperature.
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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) | 1988-10-21 | 1989-04-22 | 1989-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-10-21 | 1993-04-22 | 1993-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-10-21 | 1997-04-22 | 1997-10-22 | $7700.00 | Window Closed / Lapsed |