US4871630A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mask using lithographic image size reduction
Assignee: International Business Machines Corp
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Filing: 1987-07-31
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Granted: 1989-10-03
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Expires: 2007-07-31
Abstract
Abstract Disclosed is a process for reducing lithographic image size for integrated circuit manufacture. A mask of photosensitive material having an opening of a minimum size dictated by the limits of lithography is formed on a substrate. Reduction in the image size is achieved by establishing sidewalls to the interior vertical surfaces of the opening by depositing a conformal layer, followed by anisotropic etching. The dimension of the opening is reduced by the combined thickness of the two opposite insulator sidewalls. In a specific direct application of the disclosed process, a photomask/stencil having a pattern of openings of a minimum size smaller than possible by lighography, per se, is formed.
Inventors
- 👤 Nicholas J. Giammarco
- 👤 Alexander Gimpelson
- 👤 George A. Kaplita
- 👤 Alexander D. Lopata
- 👤 Anthony F. Scaduto
- 👤 Joseph F. Shepard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 00:23
CPC Classifications
H; H10; H10P; H10P76/00; H10P76/40; H10P76/408; H10P76/4085; H10P50/00; H10P50/69; H10P50/691; H10P50/693; H10P50/695; H10P50/696; H10P76/4088
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
131 words
A lithographic mask comprising: a substrate; an underlayer of polyimide or photoresist formed on the substrate; a release layer formed on the underlayer; a radiation-sensitive imaging layer formed on the release layer and having at least one opening extending through the imaging layer, the opening having substantially vertical walls; and inorganic sidewalls of a common and uniform thickness formed on the interior surface of all of the substantially vertical walls, the bottom edge of the sidewalls being adjacent to the release layer, whereby the size of the opening is decreased to a size smaller than that obtainable by lighography; the mask being suitable for use as an ion implantation mask, a contact mask, a mask for growing a recessed isolation oxide or a mask for forming narrow conductor or insulator lines.
Claim 2
Dependent Claim
131 words
A lithographic mask comprising: a substrate; an underlayer of polyimide or photoresist formed on the substrate; a release layer formed on the underlayer; a radiation-sensitive imaging layer formed on the release layer and having at least one opening extending through the imaging layer, the opening having substantially vertical walls; and inorganic sidewalls of a common and uniform thickness formed on the interior surface of all of the substantially vertical walls, the bottom edge of the sidewalls being adjacent to the release layer, whereby the size of the opening is decreased to a size smaller than that obtainable by lighography; the mask being suitable for use as an ion implantation mask, a contact mask, a mask for growing a recessed isolation oxide or a mask for forming narrow conductor or insulator lines.
Claim 3
Dependent Claim
174 words
A lithographic mask comprising: a substrate of semiconductor material, glass, insulator material, photosensitive material or metal; a polyimide underlayer formed directly on the substrate; a photoresist release layer formed directly on the underlayer; a hardened organic photoresist imaging layer having a thickness less than that of the underlayer, formed directly on the release layer and having at least one opening extending through the imaging layer, the opening having substantially vertical walls; and sidewalls of polysilicon, Si x O y , silicon dioxide, silicon nitride or silicon oxynitride, the sidewalls being of a common and uniformed thickness formed directly on the interior surface of all of the substantially vertical walls, the bottom edge of the sidewalls being directly adjacent to the release layer, whereby the size of the opening is decreased to a size smaller than that obtainable by lithography; the mask being configured for use as an ion implantation mask, an etch mask, a contact mask, a mask for growing a recessed isolation oxide or a mask for forming narrow conductor or insulator lines.
Claim 4
Dependent Claim
174 words
A lithographic mask comprising: a substrate of semiconductor material, glass, insulator material, photosensitive material or metal; a polyimide underlayer formed directly on the substrate; a photoresist release layer formed directly on the underlayer; a hardened organic photoresist imaging layer having a thickness less than that of the underlayer, formed directly on the release layer and having at least one opening extending through the imaging layer, the opening having substantially vertical walls; and sidewalls of polysilicon, Si x O y , silicon dioxide, silicon nitride or silicon oxynitride, the sidewalls being of a common and uniformed thickness formed directly on the interior surface of all of the substantially vertical walls, the bottom edge of the sidewalls being directly adjacent to the release layer, whereby the size of the opening is decreased to a size smaller than that obtainable by lithography; the mask being configured for use as an ion implantation mask, an etch mask, a contact mask, a mask for growing a recessed isolation oxide or a mask for forming narrow conductor or insulator lines.
References Cited (Backward Citations)
US4234362A
Cited
US4256514A
Cited
US4259369A
Cited
US4600686A
Cited
JPS59163829A
Cited
JPS59197137A
Cited
EP0150597A1
Cited
JPS61150329A
Cited
JPS62106456A
Cited
US4778739A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-10-02 | 1993-04-03 | 1993-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-02 | 1997-04-03 | 1997-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-02 | 2001-04-03 | 2001-10-03 | $7700.00 | Window Closed / Lapsed |