Patent US6904581B1 successfully refreshed from Google Patents.
US6904581B1
Expired / Lapsed
US
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System and method for placement of dummy metal fills while preserving device matching and/or limiting capacitance increase
Assignee: Magma Design Automation LLC
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Filing: 2002-05-30
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Granted: 2005-06-07
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Expires: 2022-05-30
Abstract
Abstract Systems and methods for placement of dummy metal fills while preventing disturbance of device matching and optionally limiting capacitance increase are disclosed. A computer-automated method for locating dummy fills in an integrated circuit fabrication process generally comprises receiving an input layout of the integrated circuit and specification of device matching for the integrated circuit and locating the dummy fills in the integrated circuit according to dummy rules while preserving device matching. Locating the dummy fills may include locating the dummy fills along the at least one axis of symmetry where device matching is along an axis of symmetry and locating the dummy fills so as to preserve matching of the repeated elements where device matching is repeated matched elements. The method may also include designating at least one net of the integrated circuit as a critical net, the critical nets being only a subset of all nets of the integrated circuit, identifying metal conductors corresponding to each designated critical net from the layout file, and delineating a net blocking exclusion zone extending a distance of a minimum net blocking distance (NBD) from the metal conductor for each metal conductor identified, wherein the step of locating locates the dummy fills outside of the net blocking exclusion zone.
Inventors
- 👤 Soo-Young Oh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 14:02
CPC Classifications
G; G06; G06F; G06F30/00; G06F30/30; G06F30/39
Claims Analysis
Total Claims: 45
Claim 1
Independent Claim
159 words
A computer-automated method for locating dummy fills in an integrated circuit fabrication process, comprising: receiving as input layout of the integrated circuit, specification of device matching for the integrated circuit, and a maximum allowable capacitance increase; locating the dummy fills in the integrated circuit according to dummy rules while preserving device matching; designating at least one net of the integrated circuit as a critical net, the at least one critical net comprising only a subset of all nets of the integrated circuit; identifying metal conductors corresponding to each designated critical net from the layout file; determining a minimum net blocking distance that limits the maximum capacitance increase to the set maximum allowable capacitance increase; and for each metal conductor identified, delineating a net blocking exclusion zone extending a distance of the minimum net blocking distance from the metal conductor, wherein the step of locating the dummy fills includes locating the dummy fills outside of the net blocking exclusion zone.
Claim 2
Dependent Claim
159 words
A computer-automated method for locating dummy fills in an integrated circuit fabrication process, comprising: receiving as input layout of the integrated circuit, specification of device matching for the integrated circuit, and a maximum allowable capacitance increase; locating the dummy fills in the integrated circuit according to dummy rules while preserving device matching; designating at least one net of the integrated circuit as a critical net, the at least one critical net comprising only a subset of all nets of the integrated circuit; identifying metal conductors corresponding to each designated critical net from the layout file; determining a minimum net blocking distance that limits the maximum capacitance increase to the set maximum allowable capacitance increase; and for each metal conductor identified, delineating a net blocking exclusion zone extending a distance of the minimum net blocking distance from the metal conductor, wherein the step of locating the dummy fills includes locating the dummy fills outside of the net blocking exclusion zone.
Claim 3
Dependent Claim
19 words
The method of claim 1 , wherein said determining the minimum net blocking distance comprises utilizing capacitance simulation software.
Claim 4
Dependent Claim
17 words
The method of claim 2 , wherein said capacitance simulation software is one of PASCAL™ and RAPHAEL™.
Claim 5
Dependent Claim
24 words
The method of claim 1 , wherein said determining the minimum net blocking distance comprises evaluating only the at least one designated critical net.
Claim 6
Dependent Claim
24 words
The system of claim 1 , wherein the maximum capacitance increase input is a capacitance increase level that ensures functionality of the integrate circuit.
Claim 7
Independent Claim
192 words
A system for locating dummy fills in an integrated circuit fabrication process, comprising: an input for receiving data that includes layout of the integrated circuit, specification of device matching for the integrated circuit, a maximum capacitance increase, and designation of at least one net of the integrated circuit as a designated critical net, the at least one critical net comprising only a subset of and less than all nets of the integrated circuit; a dummy fill locator that locates the dummy fills in the integrated circuit according to dummy rules while preserving device matching and that locates the dummy fills outside of the net blocking exclusion zone according to dummy rules; a metal conductor identification processor for identifying metal conductors corresponding to each designated critical net from the layout file; an exclusion zone processor for delineating a net blocking exclusion zone extending a distance of a minimum net blocking distance from the metal conductor for each metal conductor identified; and a minimum net blocking distance processor for determining the minimum net blocking distance, the minimum net blocking distance being a distance that limits the maximum capacitance increase to the received maximum capacitance.
Claim 8
Independent Claim
192 words
A system for locating dummy fills in an integrated circuit fabrication process, comprising: an input for receiving data that includes layout of the integrated circuit, specification of device matching for the integrated circuit, a maximum capacitance increase, and designation of at least one net of the integrated circuit as a designated critical net, the at least one critical net comprising only a subset of and less than all nets of the integrated circuit; a dummy fill locator that locates the dummy fills in the integrated circuit according to dummy rules while preserving device matching and that locates the dummy fills outside of the net blocking exclusion zone according to dummy rules; a metal conductor identification processor for identifying metal conductors corresponding to each designated critical net from the layout file; an exclusion zone processor for delineating a net blocking exclusion zone extending a distance of a minimum net blocking distance from the metal conductor for each metal conductor identified; and a minimum net blocking distance processor for determining the minimum net blocking distance, the minimum net blocking distance being a distance that limits the maximum capacitance increase to the received maximum capacitance.
Claim 9
Dependent Claim
24 words
The system of claim 6 , wherein the maximum capacitance increase input is a capacitance increase level that ensures functionality of the integrate circuit.
Claim 10
Dependent Claim
25 words
The system of claim 6 , wherein said minimum net blocking distance processor comprises a capacitance simulation software to determine the minimum net blocking distance.
Claim 11
Dependent Claim
17 words
The system of claim 8 , wherein said capacitance simulation software is one of PASCAL™ and RAPHAEL™.
Claim 12
Dependent Claim
22 words
The system of claim 6 , wherein said minimum net blocking distance processor evaluates only the at least one designated critical net.
Claim 13
Dependent Claim
59 words
A computer-automated method for locating dummy fills in an integrated circuit fabrication process, comprising the steps of: receiving as input layout of the integrated circuit and specification of at least one axis of symmetry along which the integrated circuit has device matching; and locating the dummy fills in the integrated circuit according to dummy rules while preserving device matching.
Claim 14
Dependent Claim
59 words
A computer-automated method for locating dummy fills in an integrated circuit fabrication process, comprising the steps of: receiving as input layout of the integrated circuit and specification of at least one axis of symmetry along which the integrated circuit has device matching; and locating the dummy fills in the integrated circuit according to dummy rules while preserving device matching.
Claim 15
Dependent Claim
27 words
The method of claim 1 , wherein said step of locating the dummy fills comprises: locating the dummy fills along the at least one axis of symmetry.
Claim 16
Dependent Claim
99 words
The method of claim 1 , further comprising the steps of: designating at least one net of the integrated circuit as a critical net, the at least one critical net comprising only a subset of all nets of the integrated circuit; identifying metal conductors corresponding to each designated critical net from the layout file; and for each metal conductor identified, delineating a net blocking exclusion zone extending a distance of a minimum net blocking distance from the metal conductor, wherein the step of locating the dummy fills includes locating the dummy fills outside of the net blocking exclusion zone.
Claim 17
Dependent Claim
41 words
The method of claim 13 , further comprising the step of receiving critical net input for the at least one critical net to be designated, said receiving input being one of from a user and from output of a CAD tool.
Claim 18
Dependent Claim
28 words
The method of claim 13 , further comprising receiving the minimum net blocking distance as an input from one of a user and output of a software program.
Claim 19
Dependent Claim
14 words
The method of claim 13 , further comprising setting the minimum net blocking distance.
Claim 20
Dependent Claim
34 words
The method of claim 13 , further comprising: receiving a maximum allowable capacitance increase; and determining the minimum net blocking distance that limits the maximum capacitance increase to the set maximum allowable capacitance increase.
Claim 21
Dependent Claim
19 words
The method of claim 17 , wherein said determining the minimum net blocking distance comprises utilizing capacitance simulation software.
Claim 22
Dependent Claim
17 words
The method of claim 18 , wherein said capacitance simulation software is one of PASCAL™ and RAPHAEL™.
Claim 23
Dependent Claim
24 words
The method of claim 17 , wherein said determining the minimum net blocking distance comprises evaluating only the at least one designated critical net.
Claim 24
Dependent Claim
23 words
The method of claim 13 , wherein said identifying comprises identifying all metal conductors corresponding to the at least one designated critical net.
Claim 25
Dependent Claim
20 words
The method of claim 13 , wherein said identifying comprises one of net tracing and tagging using the layout file.
Claim 26
Dependent Claim
33 words
The method of claim 22 , wherein said identifying comprises net tracing where the layout file is in GDS-II format and said identifying comprises tagging where the layout file contains net connectivity information.
Claim 27
Dependent Claim
28 words
The method of claim 22 , wherein when the layout file contains net connectivity information, the layout file is in one of annotated GDS-II format and LEF/DEF format.
Claim 28
Dependent Claim
50 words
The method of claim 13 , wherein said net blocking exclusion zone includes at least a blocked zone in a designated signal net layer containing the corresponding metal conductor and in any other layers that are within a distance of the minimum net blocking distance from the corresponding metal conductor.
Claim 29
Dependent Claim
29 words
The method of claim 13 , wherein said locating the dummy fills comprises utilizing at least one of a model-based dummy filling process and a rule-based dummy filling process.
Claim 30
Independent Claim
64 words
A system for locating dummy fills in an integrated circuit fabrication process, comprising: an input for receiving data that includes layout of the integrated circuit and specification of at least one axis of symmetry along which the integrated circuit has device matching; and a dummy fill locator that locates the dummy fills in the integrated circuit according to dummy rules while preserving device matching.
Claim 31
Independent Claim
64 words
A system for locating dummy fills in an integrated circuit fabrication process, comprising: an input for receiving data that includes layout of the integrated circuit and specification of at least one axis of symmetry along which the integrated circuit has device matching; and a dummy fill locator that locates the dummy fills in the integrated circuit according to dummy rules while preserving device matching.
Claim 32
Dependent Claim
31 words
The system of claim 27 , wherein said dummy fill locator preserves device matching by locating the dummy fills along the at least one axis of symmetry according to dummy rules.
Claim 33
Dependent Claim
117 words
The system of claim 27 , wherein the input data also designates at least one net of the integrated circuit as a designated critical net, the at least one critical net comprising only a subset of and less than all nets of the integrated circuit, further comprising: a metal conductor identification processor for identifying metal conductors corresponding to each designated critical net from the layout file; and an exclusion zone processor for delineating a net blocking exclusion zone extending a distance of a minimum net blocking distance from the metal conductor for each metal conductor identified, wherein the dummy fill locator also locates the dummy fills outside of the net blocking exclusion zone according to dummy rules.
Claim 34
Dependent Claim
23 words
The system of claim 29 , wherein the critical net input is from one of a user and output of a CAD tool.
Claim 35
Dependent Claim
18 words
The system of claim 29 , wherein the input additionally receives the minimum net blocking distance as input.
Claim 36
Dependent Claim
53 words
The system of claim 29 , wherein the input additionally receives a maximum capacitance increase as input, the system further comprising: a minimum net blocking distance processor for determining the minimum net blocking distance, the minimum net blocking distance being a distance that limits the maximum capacitance increase to the received maximum capacitance.
Claim 37
Dependent Claim
24 words
The system of claim 32 , wherein the maximum capacitance increase input is a capacitance increase level that ensures functionality of the integrate circuit.
Claim 38
Dependent Claim
25 words
The system of claim 32 , wherein said minimum net blocking distance processor comprises a capacitance simulation software to determine the minimum net blocking distance.
Claim 39
Dependent Claim
17 words
The system of claim 34 , wherein said capacitance simulation software is one of PASCAL™ and RAPHAEL™.
Claim 40
Dependent Claim
22 words
The system of claim 32 , wherein said minimum net blocking distance processor evaluates only the at least one designated critical net.
Claim 41
Dependent Claim
25 words
The system of claim 29 , wherein said metal conductor identification processor identifies all metal conductors corresponding to the at least one designated critical net.
Claim 42
Dependent Claim
25 words
The system of claim 29 , wherein said metal conductor identification processor performs at least one of net tracing and tagging using the layout file.
Claim 43
Dependent Claim
45 words
The system of claim 38 , wherein said metal conductor identification processor performs net tracing where the layout file is in GDS-II format and said metal conductor identification processor performs tagging where the layout file is in one of annotated GDS-II format and LEF/DEF format.
Claim 44
Dependent Claim
56 words
The system of claim 29 , wherein said exclusion zone processor delineates the net blocking exclusion zone to include at least a blocked zone in a designated signal net layer containing the corresponding metal conductor and in any other layers that are within a distance of the minimum net blocking distance from the corresponding metal conductor.
Claim 45
Dependent Claim
27 words
The system of claim 29 , wherein said dummy fill locator utilizes at least one of a model-based dummy fill locator and a rule-based dummy fill locator.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2008-06-06 | 2008-12-06 | 2009-06-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2012-06-06 | 2012-12-06 | 2013-06-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2016-06-06 | 2016-12-06 | 2017-06-07 | $7700.00 | Window Closed / Lapsed |