# US 10,372,870 B2 · Homotopy optimized parasitic extraction

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- Number: US 10,372,870 B2
- Document ID: US10372870B2
- Status: Granted
- Kind: B2
- Application number: 15/201,279
- Filed: 2016-07-01
- Published: 2018-01-04
- Granted: 2019-08-06
- Earliest claimed: 2016-07-01
- Assignees: Mentor Graphics Corporation
- Applicants: Mentor Graphics Corporation
- Inventors: Sandeep Koranne
- Web page: https://patentgrep.com/patent/US10372870B2

## CPC

- G06F 30/398: Design verification or optimisation, e.g. using design rule check [DRC], layout versus schematics [LVS] or finite element methods [FEM] (optical proximity correction [OPC] design processes G03F1/36)
- G06F 30/39: Circuit design at the physical level (physical level design for reconfigurable circuits G06F30/347)
- Y02E 60/00: Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y04S 40/20: Information technology specific aspects, e.g. CAD, simulation, modelling, system security
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y04S: SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS

## Abstract

Aspects of the disclosed technology relate to techniques of parasitic extraction. A signature for a set of geometric elements of a layout design is computed based on contour-related information. The set of geometric elements corresponds to a net of connected equipotential interconnects of a circuit design. Based on comparing the signature with signatures for sets of geometric elements that have computed parasitic element values, parasitic element values for the set of geometric elements are determined.

## Claims

### Claim 1

One or more non-transitory computer-readable media storing computer-executable instructions for causing one or more processors to perform a method, the method comprising:
receiving layout design data of an integrated circuit comprising a plurality of nets, each net being a connected group of equipotential interconnects and comprising a set of geometrical elements;
computing a first signature of a first net of the nets based on contour-related information;
obtaining a second signature of a second net of the nets;
determining that the following conditions are true:
the first signature matches a first precomputed signature of a first precomputed net;
the second signature matches a second precomputed signature of a second precomputed net; and
relative location information of the first and second nets matches relative location information of the first and second precomputed nets;
responsive to the determining, assigning a precomputed parasitic capacitance value to the first net; and
forwarding the layout design data, with the precomputed parasitic capacitance value assigned to the first net, to an electronic design automation tool for physical verification.

### Claim 2 (depends on 1)

The one or more non-transitory computer-readable media recited in claim 1, wherein the first signature is computed based on third signatures for geometric elements on individual physical layers and on fourth signatures for interconnects between the physical layers.

### Claim 3 (depends on 2)

The one or more non-transitory computer-readable media recited in claim 2, wherein the third signatures for geometric elements on individual physical layers are derived using a mathematical function.

### Claim 4 (depends on 1)

The one or more non-transitory computer-readable media recited in claim 1, wherein the contour-related information is generated based on a rasterizing scanline analysis of the geometrical elements on individual physical layers.

### Claim 5 (depends on 1)

The one or more non-transitory computer-readable media of claim 1, wherein the method further comprises:
computing a third signature of a third net of the nets;
determining that the third signature does not match any previously computed signature of the nets; and
responsive to the determining for the third signature, computing parasitic element values for the third net.

### Claim 6 (depends on 1)

The one or more non-transitory computer-readable media of claim 1, wherein the method further comprises:
computing a third signature of a third net of the nets;
determining that the third signature matches a third precomputed signature of a third precomputed net, and relative location information of the second and third nets does not match relative location information of the second and third precomputed nets; and
responsive to the not matching determination, computing a parasitic capacitance value for the third net.

### Claim 7

A method, executed by at least one processor of a computer, comprising:
by the at least one processor of the computer:
receiving layout design data of an integrated circuit comprising a plurality of nets, each net being a set of equipotential interconnects corresponding to a set of geometrical elements;
computing a first signature for a first one of the nets based on contour-related information; and
obtaining a second signature of a second one of the nets matching a first precomputed signature of a first precomputed net;
determining that:
the first signature matches a second precomputed signature of a second precomputed net; and
relative location information of the first and second nets matches relative location information of the second and first precomputed nets;
subsequent to the determining, associating a precomputed parasitic capacitance value with the first net; and
forwarding the layout design data, with the associated precomputed parasitic capacitance value of the first net, to an electronic design automation tool for physical verification.

### Claim 8 (depends on 7)

The method recited in claim 7, wherein the first signature is computed based on third signatures for geometric elements on individual physical layers and on fourth signatures for interconnects between the physical layers.

### Claim 9 (depends on 8)

The method recited in claim 8, wherein the third signatures for geometric elements on individual physical layers are derived using a mathematical function.

### Claim 10 (depends on 7)

The method recited in claim 7, wherein the contour-related information is generated based on a rasterizing scanline analysis of the geometrical elements on individual physical layers.

### Claim 11 (depends on 7)

The method of claim 7, further comprising:
computing a third signature of a third net of the nets;
determining that the third signature does not match any previously computed signature of the nets; and
responsive to the determining for the third signature, computing parasitic element values for the third net.

### Claim 12 (depends on 11)

The method of claim 11, wherein the parasitic element values for the third net comprise a parasitic resistance value, a parasitic capacitance value, or both.

### Claim 13 (depends on 7)

The method of claim 7, further comprising:
computing a third signature of a third net of the nets;
determining that the third signature matches a third precomputed signature of a third precomputed net, and relative location information of the second and third nets does not match relative location information of the first and third precomputed nets; and
responsive to the not matching determination, computing a parasitic capacitance value for the third net.

### Claim 14

A system comprising:
one or more processors with memory coupled thereto, the one or more processors programmed to perform a method, the method comprising:
receiving layout design data of an integrated circuit comprising a plurality of nets, each net being a connected group of equipotential interconnects and comprising a set of geometrical elements;
computing a first signature of a first net of the nets based on second signatures of respective geometric elements on single physical layers and on third signatures of interconnects between the single physical layers, the second signatures being based on contour-related information; and
determining parasitic element values for the first net based on comparing the first signature with fourth signatures of previously computed second nets, the second nets having previously computed parasitic element values; and
forwarding the layout design data, with the determined parasitic element values for the first net, to an electronic design automation tool for physical verification.

### Claim 15 (depends on 14)

The system recited in claim 14, wherein the determining comprises:
associating some of the previously computed parasitic element values with the first net if the first signature matches one of the fourth signatures; and
computing new parasitic element values for the first net and adding the first signature to the fourth signatures if the first signature matches none of the fourth signatures.

### Claim 16 (depends on 14)

The system recited in claim 14, wherein the determining comprises:
associating some of the computed parasitic element values with the first net if the first signature matches one of the fourth signatures, a fifth signature for a second net matches another one of the fourth signatures, and relative location information of the first net and the second net matches one for corresponding two sets of computed geometric elements relative location information of the two previously computed second nets corresponding to the matched fourth signatures.

### Claim 17 (depends on 14)

The system recited in claim 14, wherein the second signatures for geometric elements on single physical layers are derived using a mathematical function.

### Claim 18 (depends on 14)

The system recited in claim 14, wherein the contour-related information is generated based on a rasterizing scanline analysis of the respective geometrical elements on single physical layers.

### Claim 19 (depends on 14)

The system of claim 14, wherein the parasitic element values comprise parasitic resistance values, parasitic capacitance values, or both.

### Claim 20 (depends on 5)

The one or more non-transitory computer-readable media of claim 5, wherein the parasitic element values for the third net comprise parasitic resistance values, parasitic capacitance values, or both.