US6128768A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of extracting layout parasitics for nets of an integrated circuit using a connectivity-based approach
Assignee: Synopsys Inc
•
Filing: 1997-07-16
•
Granted: 2000-10-03
•
Expires: 2017-07-16
Abstract
Abstract A layout parasitic extraction system is disclosed. The present invention is a connectivity-based approach for extracting layout parasitics. The present invention creates a connectivity-based database, where geometries of a layout are organized by net. The present invention allows net-by-net extraction of layout parasitics using a connectivity-based database. Furthermore, a user can select a net or nets for extraction. The present invention outputs a database containing nets and their extracted layout parasitics. The present invention can create a netlist format file from a database containing nets and their extracted parasitics to allow back annotation of layout parasitics into a circuit schematic or for use for other software (possibly from a third-party).
Inventors
- 👤 William Wai Yan Ho
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 13:19
CPC Classifications
G; G06; G06F; G06F30/00; G06F30/30; G06F30/39; G06F30/398
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
155 words
A method of extracting layout parasitic information comprising: providing a netlist database describing devices and nets of a circuit design; providing a layout database describing geometries of the circuit design; creating from the netlist database and layout database a connectivity-based database where the geometries of the circuit design are organized by nets; providing a predefined structure database comprising a plurality of predefined structures and a plurality of previously extracted parasitic values corresponding to the predefined structures; tracing along a selected net of the connectivity database to find parasitic structures formed by the geometries of the selected net; comparing each of the parasitic structures of the selected net of the connectivity database to the predefined structures in the predefined structure database; and for each parasitic structure of the connectivity-based database that matches one of the predefined structures, using a previously extracted parasitic value from the predefined structure database in determining layout parasitics for the selected net.
Claim 2
Independent Claim
155 words
A method of extracting layout parasitic information comprising: providing a netlist database describing devices and nets of a circuit design; providing a layout database describing geometries of the circuit design; creating from the netlist database and layout database a connectivity-based database where the geometries of the circuit design are organized by nets; providing a predefined structure database comprising a plurality of predefined structures and a plurality of previously extracted parasitic values corresponding to the predefined structures; tracing along a selected net of the connectivity database to find parasitic structures formed by the geometries of the selected net; comparing each of the parasitic structures of the selected net of the connectivity database to the predefined structures in the predefined structure database; and for each parasitic structure of the connectivity-based database that matches one of the predefined structures, using a previously extracted parasitic value from the predefined structure database in determining layout parasitics for the selected net.
Claim 3
Dependent Claim
39 words
The method of claim 1 further comprising: for each parasitic structure of the connectivity database that does not match one of the predetermined structures, calculating a calculated parasitic value to use in determining layout parasitics for the selected net.
Claim 4
Dependent Claim
23 words
The method of claim 2 further comprising: adding to the predefined structure database each parasitic structure where a calculated parasitic value was found.
Claim 5
Dependent Claim
17 words
The method of claim 2 wherein the calculated parasitic value is calculated using a field solver program.
Claim 6
Dependent Claim
12 words
The method of claim 1 wherein the parasitic structures comprise parasitic resistances.
Claim 7
Dependent Claim
12 words
The method of claim 1 wherein the parasitic structures comprise parasitic capacitances.
Claim 8
Dependent Claim
13 words
The method of claim 1 wherein the layout database is in GDSII format.
Claim 9
Dependent Claim
14 words
The method of claim 1 wherein the selected net is selected by a user.
Claim 10
Dependent Claim
18 words
The method of claim 1 wherein the netlist database and layout database are formed before the connectivity-based database.
Claim 11
Dependent Claim
54 words
The method of claim 1 wherein the calculating a calculated parasitic value comprises: determining a width W of a regular polygon touching an irregular polygon; creating a polygon subsection including the irregular polygon and portions of the regular polygon extending approximately a distance of W/2 in at least two directions from the irregular polygon.
Claim 12
Dependent Claim
10 words
The method of claim 1 wherein the geometries comprise transistors.
Claim 13
Dependent Claim
18 words
The method of claim 1 wherein the connectivity-based database includes connectivity information for transistors of the circuit design.
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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) | 2003-10-03 | 2004-04-03 | 2004-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-10-03 | 2008-04-03 | 2008-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-10-03 | 2012-04-03 | 2012-10-03 | $7700.00 | Window Closed / Lapsed |