US6081659A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Comparing aerial image to actual photoresist pattern for masking process characterization
Assignee: Bell Semiconductor LLC
•
Filing: 1999-04-26
•
Granted: 2000-06-27
•
Expires: 2019-04-26
Abstract
Abstract A method of simulating a masking process in which a process simulator is used to produce an aerial image. The simulator is configured to receive input information. The input information includes a digital representation of a patterned mask and a data set. Each element of the data set corresponds to one of a plurality of parameters associated with the masking process. The simulator is configured to produce an aerial image based upon the input information. The aerial image represents the simulator estimation of a pattern that would be produced by the masking process using the patterned mask under conditions specified by the data set. The method further includes the step of supplying the input information to the simulator to produce the aerial image. A first data base is then generated from the aerial image. The first data base is a digital representation of the aerial image. Thereafter, the pattern is produced on a semiconductor substrate using the masking process and the patterned mask. The pattern is produced under the conditions specified by the data set. A second data base is then generated wherein the second data base is a digital representation of the actual pattern. The first data base and the second data base are then compared to produce an error data base. The error data base is indicative of differences between the aerial image and the pattern. Thereafter, the process simulator is modified based upon the error data base to minimize the differences between a successive iteration of the aerial image and the pattern.
Inventors
- 👤 Mario Garza
- 👤 Keith K. Chao
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 08:12
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/36
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
167 words
In the field of semiconductor processing, a method of simulating a photoresist process, comprising: supplying a first database comprising a digital representation of an aerial image of an estimated photoresist pattern, wherein said aerial image was produced by a process simulator simulation of a photoresist process using a patterned mask under conditions specified by a data set, wherein each element of said data set corresponds to one of a plurality of parameters associated with said photoresist process; supplying a second database comprising a digital representation of an actual photoresist pattern, wherein said actual photoresist pattern was produced by a process using said photoresist process and said patterned mask under the conditions specified by said data set; comparing said first database with said second database to produce an error database indicative of differences between said aerial image and said actual photoresist pattern; and modifying said process simulator based upon said error database to minimize said differences between a successive iteration of said aerial image and said photoresist pattern.
Claim 2
Dependent Claim
167 words
In the field of semiconductor processing, a method of simulating a photoresist process, comprising: supplying a first database comprising a digital representation of an aerial image of an estimated photoresist pattern, wherein said aerial image was produced by a process simulator simulation of a photoresist process using a patterned mask under conditions specified by a data set, wherein each element of said data set corresponds to one of a plurality of parameters associated with said photoresist process; supplying a second database comprising a digital representation of an actual photoresist pattern, wherein said actual photoresist pattern was produced by a process using said photoresist process and said patterned mask under the conditions specified by said data set; comparing said first database with said second database to produce an error database indicative of differences between said aerial image and said actual photoresist pattern; and modifying said process simulator based upon said error database to minimize said differences between a successive iteration of said aerial image and said photoresist pattern.
Claim 3
Dependent Claim
95 words
The method of claim 1, wherein said process simulator comprises a computer, said computer including: a storage device, wherein said storage device is configured with computer instructions designed to generate, upon execution, said aerial image from said patterned mask and said data set; an input device for receiving said patterned mask and said data set and for storing said patterned mask and said data set in said storage device; and a processor coupled to said input device and said storage device, for executing said computer instructions and storing said aerial image in said storage device.
Claim 4
Dependent Claim
30 words
The method of claim 2, wherein said input device comprises a disk drive configured to receive a disk including a digital representation of said patterned mask and said data set.
Claim 5
Dependent Claim
27 words
The method of claim 2, wherein said computer further includes: an output device for providing either a hard copy or a digital representation of said aerial image.
Claim 6
Dependent Claim
67 words
The method of claim 1, wherein said plurality of parameters associated with said photoresist process include parameters selected from the group consisting of at least one of: resist contrast (γ), resist thickness, resist sensitivity, resist solids content, resist viscosity, soft bake temperature, soft bake duration, exposure intensity, exposure duration, source wavelength, source coherency, develop time, developer concentration, developer temperature, developer agitation method, post-bake temperature, and post-bake time.
Claim 7
Dependent Claim
37 words
The method of claim 1, wherein said supplying said second database comprises: scanning said actual photoresist pattern with a scanning electron microscope to produce a scanned image; and digitizing said scanned image to produce said second database.
Claim 8
Dependent Claim
55 words
The method of claim 1, wherein said aerial image includes an alignment mark and said actual photoresist pattern includes a corresponding alignment mark and wherein said comparing said first database with said second database is facilitated by superimposing said alignment mark of said aerial image with said corresponding alignment mark of said actual photoresist pattern.
Claim 9
Dependent Claim
18 words
The method of claim 1, wherein said patterned mask comprises features distorted by an optimal proximity correction routine.
Claim 10
Dependent Claim
173 words
In the field of semiconductor processing, a method of simulating a photoresist process, comprising: supplying an aerial image from a process simulator of an estimated photoresist pattern that would be produced by a photoresist process using a patterned mask under conditions specified by a data set, wherein each element of said data set corresponds to one of a plurality of parameters associated with said photoresist process; generating a first database comprising a digital representation of said aerial image; supplying an actual photoresist pattern, wherein said actual photoresist pattern was produced by a process using said photoresist process and said patterned mask under the conditions specified by said data set; generating a second database comprising a digital representation of said actual photoresist pattern; comparing said first database with said second database to produce an error database indicative of differences between said aerial image and said actual photoresist pattern; and modifying said process simulator based upon said error database to minimize said differences between a successive iteration of said aerial image and said photoresist pattern.
Claim 11
Dependent Claim
173 words
In the field of semiconductor processing, a method of simulating a photoresist process, comprising: supplying an aerial image from a process simulator of an estimated photoresist pattern that would be produced by a photoresist process using a patterned mask under conditions specified by a data set, wherein each element of said data set corresponds to one of a plurality of parameters associated with said photoresist process; generating a first database comprising a digital representation of said aerial image; supplying an actual photoresist pattern, wherein said actual photoresist pattern was produced by a process using said photoresist process and said patterned mask under the conditions specified by said data set; generating a second database comprising a digital representation of said actual photoresist pattern; comparing said first database with said second database to produce an error database indicative of differences between said aerial image and said actual photoresist pattern; and modifying said process simulator based upon said error database to minimize said differences between a successive iteration of said aerial image and said photoresist pattern.
Claim 12
Dependent Claim
67 words
The method of claim 9, wherein said plurality of parameters associated with said photoresist process include parameters selected from the group consisting of at least one of: resist contrast (γ), resist thickness, resist sensitivity, resist solids content, resist viscosity, soft bake temperature, soft bake duration, exposure intensity, exposure duration, source wavelength, source coherency, develop time, developer concentration, developer temperature, developer agitation method, post-bake temperature, and post-bake time.
Claim 13
Dependent Claim
37 words
The method of claim 9, wherein said generating said second database comprises: scanning said actual photoresist pattern with a scanning electron microscope to produce a scanned image; and digitizing said scanned image to produce said second database.
Claim 14
Dependent Claim
55 words
The method of claim 9, wherein said aerial image includes an alignment mark and said actual photoresist pattern includes a corresponding alignment mark and wherein said comparing said first database with said second database is facilitated by superimposing said alignment mark of said aerial image with said corresponding alignment mark of said actual photoresist pattern.
Claim 15
Dependent Claim
18 words
The method of claim 9, wherein said patterned mask comprises features distorted by an optimal proximity correction routine.
References Cited (Backward Citations)
US4812962A
Cited
US5434102A
Cited
US5725973A
Cited
GB2291219A
Cited
EP0698916A2
Cited
US5745388A
Cited
US5633713A
Cited
US5681674A
Cited
US5682323A
Cited
US5553274A
Cited
US5553273A
Cited
US5879844A
Cited
US5705301A
Cited
EP0822452A2
Cited
US5801954A
Cited
US5862058A
Cited
US5795688A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-06-27 | 2003-12-27 | 2004-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-06-27 | 2007-12-27 | 2008-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-06-27 | 2011-12-27 | 2012-06-27 | $7700.00 | Window Closed / Lapsed |