Patent US4448635A successfully refreshed from Google Patents.
US4448635A
Expired / Lapsed
US
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Method of etching cavities and apertures in substrates and device for carrying out said method
Assignee: US Philips Corp
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Filing: 1983-02-04
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Granted: 1984-05-15
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Expires: 2003-02-04
Abstract
Abstract Deep cavities and apertures can be obtained with little undercutting (great etching factor) by etching in an artificial gravitational field (under the influence of centrifugal or centripetal forces).
Inventors
- 👤 Hendrik K. Kuiken
- 👤 Rudolf P. Tijburg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 07:49
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/02
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
62 words
A method of etching cavities and apertures in a substrate comprising subjecting said substrate to the action of an etchant characterized in that the etching takes place in an artificial gravitational field causing a relative movement of the etchant in regard to the substrate solely by virtue of the difference of the density between the etchant and the products formed during etching.
Claim 2
Independent Claim
62 words
A method of etching cavities and apertures in a substrate comprising subjecting said substrate to the action of an etchant characterized in that the etching takes place in an artificial gravitational field causing a relative movement of the etchant in regard to the substrate solely by virtue of the difference of the density between the etchant and the products formed during etching.
Claim 3
Dependent Claim
54 words
An etching method as claimed in claim 1, characterized in that the substrate to be etched is arranged relative to the artificial gravitational field in such manner that it experiences a force which is directed away from the surface in the case in which the formed etching products increase the density of the etchant.
Claim 4
Dependent Claim
53 words
An etching method as claimed in claim 1, characterized in that the substrate to be etched is arranged relative to the artificial gravitational field in such manner that it experiences a force which is directed towards the surface in the case in which the formed etching products increase the density of the etchant.
Claim 5
Dependent Claim
57 words
An etching method as claimed in claim 1, characterized in that the substrate to be etched is arranged relative to the artificial gravitational field in such manner that it experiences a force which is perpendicular to and is directed towards the surface in the case in which the formed etching products decrease the density of the etchant.
Claim 6
Dependent Claim
54 words
An etching method as claimed in claim 1, characterized in that the substrate to be etched is arranged relative to the artificial gravitational field in such manner that it experiences a force which is directed away from the surface in the case in which the formed etching products decrease the density of the etchant.
Claim 7
Dependent Claim
69 words
A method as claimed in claim 1, characterized in that the acceleration of the gravitational field used is chosen to be so that ##EQU2## wherein a and a r are the acceleration to be used and the acceleration in a blank experiment, respectively, and 1 and l r are the diameter of the cavity to be etched and the diameter of a Benard cell in the blank experiment, respectively.
References Cited (Backward Citations)
DE143333C
Cited
US2869266A
Cited
US2867929A
Cited
US3383255A
Cited
US3730799A
Cited
US4137118A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-05-15 | 1987-11-14 | 1988-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-05-15 | 1991-11-14 | 1992-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-05-15 | 1995-11-14 | 1996-05-15 | $7700.00 | Window Closed / Lapsed |