US3721592A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Etching method employing an etching mask while suppressing underetching
Assignee: US Philips Corp
•
Filing: 1970-05-04
•
Granted: 1973-03-20
•
Expires: 1990-05-04
Abstract
Abstract The invention relates to etching with the aid of a mask while limiting underetching as much as possible by using an etchresistant and stable mask and by filling up after some time of etching, the cavities produced by underetching underneath the metal film with an etch-resistant resist by means of a photomechanical method.
Inventors
- 👤 Werdt R De
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 20:05
CPC Classifications
H; H10; H10P; H10P95/00; C; C03; C03C; C03C15/00; C23; C23F; C23F1/00; C23F1/02; G; G03; G03F; G03F7/00; G03F7/0035; H10P50/00; H10P50/69; H10P50/691; H10P50/692; H10P50/693; H10P50/695; H10W; H10W74/00; H10W74/40; H10W74/43; Y; Y10; Y10S; Y10S148/00; Y10S148/051; Y10S148/106; Y10S438/00; Y10S438/942; Y10S438/945; Y10S438/948; Y10S438/95
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
13 words
A method as claimed in claim 1 wherein the mask is of metal.
Claim 2
Dependent Claim
13 words
A method as claimed in claim 2 wherein the mask is of nickel.
Claim 3
Independent Claim
222 words
A method of removing by etching first portions of a surface layer while leaving a second portion of the surface layer intact and without excessive underetching of the second portion, comprising: a. forming on the surface so as to cover the second portion a non-deformable mask which is etch-resistant and which is radiation-impermeable, b. subjecting the first surface portions to a first etching treatment with an etchant to which the mask is resistant until some first surface portions are removed including an underetched area underneath the non-deformable mask edges, c. coating the surface including the mask, the etched first surface portions and the underetched area underneath the mask with a positive radiation-sensitive etch-resistant layer, d. exposing the radiation-sensitive etch-resistant layer from above the non-deformable mask to radiation to which the mask is impermeable but the etch-resistant layer sensitive whereby the layer portions in the underetched area and shielded by the mask remain unexposed to the radiation, e. selectively removing exposed portions of the radiation-sensitive etch-resistant layer leaving unexposed etch-resistant layer portions in the underetched area, f. and thereafter while the mask and etch-resistant layer portions remain in place subjecting the surface layer to a second etching treatment with an etchant to which the mask and the etch-resistant layer portions remaining are resistant until additional regions of the first surface portions are removed.
Claim 4
Dependent Claim
26 words
A method as set forth in claim 4 wherein the mask is of metal with a thickness of at least of the order of 0.1 micrometers.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-19 | 1976-09-18 | 1977-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-19 | 1980-09-18 | 1981-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-19 | 1984-09-18 | 1985-03-20 | $7700.00 | Window Closed / Lapsed |