US5538833A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High resolution phase edge lithography without the need for a trim mask
Assignee: GlobalFoundries Inc
•
Filing: 1994-08-03
•
Granted: 1996-07-23
•
Expires: 2014-08-03
Abstract
Abstract A process of phase edge lithography is employed in the manufacture of very large scale integrated (VLSI) chips in which chrome images are biased on a phase edge of a phase shift mask (PSM) and the mask overexposed to compensate for the positive bias. This overexposure eliminates any residual images from the phase edge mask with minimum impact to the desired images. This simple process results in a trim-less phase edge process that takes advantage of the improved resolution and process latitude of phase edge PSMs while avoiding layout impacts caused by a trim mask or other phase edge elimination methods.
Inventors
- 👤 Richard A. Ferguson
- 👤 Lars W. Liebmann
- 👤 Ronald M. Martino
- 👤 Thomas H. Newman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 09:52
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/26; G03F1/34; H; H10; H10P; H10P76/00
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
77 words
A method of high resolution phase edge trim-less lithography comprising the steps of: providing a phase edge phase shift mask (PSM) with chrome images on the mask biased a predetermined amount; overexposing a resist using the mask to compensate for the positive bias of the mask thereby eliminating any residual images produced by the mask with minimum impact to desired images; and processing the exposed resist to yield an exposure pattern of improved resolution and process latitude.
Claim 2
Independent Claim
77 words
A method of high resolution phase edge trim-less lithography comprising the steps of: providing a phase edge phase shift mask (PSM) with chrome images on the mask biased a predetermined amount; overexposing a resist using the mask to compensate for the positive bias of the mask thereby eliminating any residual images produced by the mask with minimum impact to desired images; and processing the exposed resist to yield an exposure pattern of improved resolution and process latitude.
Claim 3
Dependent Claim
31 words
The process according to claim 1 wherein the chrome images on the mask are oversized by a predetermined amount, the step of overexposing returning features of the images to intended sizes.
Claim 4
Dependent Claim
13 words
The process according to claim 2 wherein the overexposure is at least 10-15%.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-07-23 | 2000-01-22 | 2000-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-07-23 | 2004-01-22 | 2004-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-07-23 | 2008-01-22 | 2008-07-23 | $7700.00 | Window Closed / Lapsed |