US5901063A
Expired / Lapsed
US
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System and method for extracting parasitic impedance from an integrated circuit layout
Assignee: Ansys Inc
•
Filing: 1997-02-21
•
Granted: 1999-05-04
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Expires: 2017-02-21
Abstract
Abstract A comprehensive system and method allow an integrated circuit designer to extract accurate estimates of parasitic impedances in interconnection lines of an integrated circuit. The method includes collecting values of electrical characteristic parameters to provide a technology profile for a particular fabrication process. An Interconnect Primitive Library builder provides a collection of interconnect `primitives` that any interconnect structure fabricated under the fabrication process can be broken down into, and combines it with the technology profile for simulations in a 3-dimensional field solver to extract parameterized coupling capacitances and other characteristic impedances for each interconnect primitive. An extraction tool traces a signal path of an integrated circuit and decomposes the interconnect structures on the signal path into interconnect primitives and maps them to the Interconnect Primitive Library. An RC network module provides an RC network based on the characterized parametric values in the mapped interconnect primitives. The RC network thus provided can be used to accurately estimate signal delays in a circuit simulator or delay calculator.
Inventors
- 👤 Keh-Jeng Chang
- 👤 Douglas Kaufman
- 👤 Martin Walker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 15:11
CPC Classifications
G; G06; G06F; G06F30/00; G06F30/30; G06F30/39; G06F30/398
Claims Analysis
Total Claims: 76
Claim 1
Independent Claim
153 words
A system for extracting parasitic impedances from an integrated circuit layout, comprising: a database including values of physical parameters characterizing conductor and dielectric layers fabricated in a fabrication process; an interconnect primitive library organized according to a set of interconnect primitives, such that an interconnect structure fabricated under said fabrication process includes a component which maps into one of said interconnect primitives, said interconnect primitive library including, for each of said interconnect primitive, parameterized data of parasitic impedances, based on said values of said physical parameters; and a network extraction tool, said network extraction tool (i) analyzing structures within a predetermined distance in conductor layers of said integrated circuit in vicinities along a signal path of said integrated circuit, and (ii) mapping components of said structures to said interconnect primitives of said interconnect primitive library to provide an electrical network model of said signal path, based on said mapping and said parameterized data.
Claim 2
Independent Claim
153 words
A system for extracting parasitic impedances from an integrated circuit layout, comprising: a database including values of physical parameters characterizing conductor and dielectric layers fabricated in a fabrication process; an interconnect primitive library organized according to a set of interconnect primitives, such that an interconnect structure fabricated under said fabrication process includes a component which maps into one of said interconnect primitives, said interconnect primitive library including, for each of said interconnect primitive, parameterized data of parasitic impedances, based on said values of said physical parameters; and a network extraction tool, said network extraction tool (i) analyzing structures within a predetermined distance in conductor layers of said integrated circuit in vicinities along a signal path of said integrated circuit, and (ii) mapping components of said structures to said interconnect primitives of said interconnect primitive library to provide an electrical network model of said signal path, based on said mapping and said parameterized data.
Claim 3
Dependent Claim
35 words
A system as in claim 1, wherein each interconnect primitive represents a capacitance coupling between a component of a structure in a selected conductor layer and a component of a structure in said signal path.
Claim 4
Dependent Claim
19 words
A system as in claim 2, wherein said structure in said signal path is in said selected conductor layer.
Claim 5
Dependent Claim
31 words
A system as in claim 3, wherein parasitic impedances of said interconnect primitive are adjusted for shielding effects arising from conductor layers other than said conductor layer of said signal path.
Claim 6
Dependent Claim
48 words
A system as in claim 3, wherein said capacitance coupling is characterized by a dimension of said component of said structure in said signal path and the distance separating said component of said structure in said signal path and the nearest structure thereto in said selected conductor layer.
Claim 7
Dependent Claim
16 words
A system as in claim 2, wherein said selected conductor layer is a substrate conductor layer.
Claim 8
Dependent Claim
48 words
A system as in claim 6, wherein said capacitance coupling is characterized by a dimension of said component of said structure in said signal path and the distance separating said component of said structure in said signal path and the nearest structure thereto in said selected conductor layer.
Claim 9
Dependent Claim
24 words
A system as in claim 2, wherein said structure in said signal path is in a different conductor layer than said selected conductor layer.
Claim 10
Dependent Claim
34 words
A system as in claim 8, wherein said interconnect primitive is further identified according to bins, each bin representing a predetermined range of distances from said component of said structure in said signal path.
Claim 11
Dependent Claim
33 words
A system as in claim 9, wherein said predetermined range of distances is process-specific and wherein said bins are characterized by a dimension of said component of said structure in said signal path.
Claim 12
Dependent Claim
23 words
A system as in claim 9, wherein said network extraction tool estimates said coupling capacitance by interpolating between interconnect primitives of neighboring bins.
Claim 13
Dependent Claim
22 words
A system as in claim 11, wherein said interpolating step includes using a function which diminishes with distance more rapidly than linearly.
Claim 14
Dependent Claim
34 words
A system as in claim 9, wherein said network extraction tool estimates said capacitance coupling taking into consideration the extent to which said structure in said selected conductor layer is present in each bin.
Claim 15
Dependent Claim
30 words
A system as in claim 8, wherein a selected surface of said structure in said selected conductor layer has a major extent in a direction orthogonal to said signal path.
Claim 16
Dependent Claim
21 words
A system as in claim 8, wherein said component of said structure in said selected conductor layer includes an edge thereof.
Claim 17
Dependent Claim
33 words
A system as in claim 15, wherein said capacitance coupling is characterized by a distance between said component in said selected conductor layer and its nearest neighboring structure in said selected conductor layer.
Claim 18
Dependent Claim
31 words
A system as in claim 8, wherein said component of said structure in said selected conductor layer is a surface oriented towards said component of said structure in said signal path.
Claim 19
Dependent Claim
32 words
A system as in claim 8, wherein said component of said structure in said selected conductor layer comprises a surface oriented away from said component of said structure in said signal path.
Claim 20
Dependent Claim
25 words
A system as in claim 8, wherein said interconnect primitive is characterized by a dimension of said component of said structure in said signal path.
Claim 21
Dependent Claim
42 words
A system as in claim 8, wherein said interconnect primitive is characterized by a spacing between said component of said structure in said signal path and the nearest structure thereto in the same conductor layer as said structure in said signal path.
Claim 22
Dependent Claim
24 words
A system as in claim 2, wherein said network extraction tool provides a capacitor in said electrical network model to represent said interconnect primitive.
Claim 23
Dependent Claim
30 words
A system as in claim 1, wherein said network extraction tool divides said structures into change areas, each change area representing a change in dimension in one of said structures.
Claim 24
Dependent Claim
50 words
A system as in claim 1, wherein said network extractor tool divides said signal path into a right portion and a left portion along a direction of signal propagation in said signal path, said network extraction tool analyzing structures in said right portion independently of structures in said left portion.
Claim 25
Dependent Claim
41 words
A system as in claim 1, wherein said network extraction tool analyzes coupling between a structure in a conductor layer of said signal path and a structure in a selected conductor layer other than said conductor layer of said signal path.
Claim 26
Dependent Claim
54 words
A system as in claim 24, wherein said network extraction tool selects a said selected conductor layer one at a time from a plurality of conductor layers in increasing order of a distance from said structure in said conductor layer of said signal path, taking into account shielding effects of conductor layers already selected.
Claim 27
Dependent Claim
79 words
A system as in claim 25, wherein said network extraction tool separately takes into account (i) shielding effects arising from capacitance coupling between said structure in said conductor layer of said signal path and structures in conductor layers on the same side of said selected conductor layer, and (ii) shielding effects arising from capacitance coupling between said structure in said conductor layer of said signal path and structures in conductor layers on opposite sides of said selected conductor layer.
Claim 28
Dependent Claim
23 words
A system as in claim 1, wherein each interconnect primitive is identified, in part, in said interconnect primitive library by a conductor layer.
Claim 29
Dependent Claim
31 words
A system as in claim 1, wherein said structures include vias, and wherein said network extraction tool provides in said electrical network model a resistor to represent each of said vias.
Claim 30
Dependent Claim
37 words
A system as in claim 1, further comprising an interconnect primitive library building tool, said interconnect library building tool assembling said interconnect primitive library using said values of said physical parameters and an electric field distribution solver.
Claim 31
Dependent Claim
20 words
A system as in claim 1, wherein said physical parameters include resistivity for each conductor layer in said fabrication process.
Claim 32
Dependent Claim
16 words
A system as in claim 1, wherein said physical parameters include a resistance for a via.
Claim 33
Dependent Claim
25 words
A system as in claim 1, wherein said network extraction tool traces said signal path along polygons in a conductor layer of said signal path.
Claim 34
Dependent Claim
27 words
A system as in claim 1, wherein said network extraction tool is configurable to trace said signal path up to terminals of transistors of said integrated circuit.
Claim 35
Dependent Claim
30 words
A system as in claim 1, wherein said network extraction tool is configurable to trace said signal path up to a pin of a macro cell of said integrated circuit.
Claim 36
Dependent Claim
41 words
A system as in claim 1, wherein said network extraction tool provides in said electrical network model, for each structure in a selected type of structures in said signal path, a "pi" network to represent the parasitic impedances of said structure.
Claim 37
Dependent Claim
41 words
A system as in claim 1, wherein said network extraction tool provides in said electrical network model, for each structure of a selected type of structure in said signal path, a three-terminal network to represent the parasitic impedance of said structure.
Claim 38
Dependent Claim
32 words
A system as in claim 1, wherein said network extraction tool provides said electrical network model in a format suitable for use as an input file to a specified circuit simulation tool.
Claim 39
Independent Claim
155 words
A method for extracting parasitic impedances from an integrated circuit layout, comprising: including in a database values of physical parameters characterizing conductor and dielectric layers fabricated in a fabrication process; organizing an interconnect primitive library according to a set of interconnect primitives, such that an interconnect structure fabricated under said fabrication process includes a component which maps into one of said interconnect primitives, said interconnect primitive library including, for each of said interconnect primitive, parameterized data of parasitic impedances, based on said values of said physical parameters; and providing a network extraction tool, said network extraction tool (i) analyzing structures within a predetermined distance in conductor layers of said integrated circuit in vicinities along a signal path of said integrated circuit, and (ii) mapping components of said structures to said interconnect primitives of said interconnect primitive library to provide an electrical network model of said signal path, based on said mapping and said parameterized data.
Claim 40
Independent Claim
155 words
A method for extracting parasitic impedances from an integrated circuit layout, comprising: including in a database values of physical parameters characterizing conductor and dielectric layers fabricated in a fabrication process; organizing an interconnect primitive library according to a set of interconnect primitives, such that an interconnect structure fabricated under said fabrication process includes a component which maps into one of said interconnect primitives, said interconnect primitive library including, for each of said interconnect primitive, parameterized data of parasitic impedances, based on said values of said physical parameters; and providing a network extraction tool, said network extraction tool (i) analyzing structures within a predetermined distance in conductor layers of said integrated circuit in vicinities along a signal path of said integrated circuit, and (ii) mapping components of said structures to said interconnect primitives of said interconnect primitive library to provide an electrical network model of said signal path, based on said mapping and said parameterized data.
Claim 41
Dependent Claim
36 words
A method as in claim 38, wherein each interconnect primitive represents a capacitance coupling between a component of a structure in one of said conductor layers and a component of a structure in said signal path.
Claim 42
Dependent Claim
19 words
A method as in claim 39, wherein said structure in said signal path is in said selected conductor layer.
Claim 43
Dependent Claim
31 words
A method as in claim 40, wherein parasitic impedances of said interconnect primitive are adjusted for shielding effects arising from conductor layers other than said conductor layer of said signal path.
Claim 44
Dependent Claim
48 words
A method as in claim 40, wherein said capacitance coupling is characterized by a dimension of said component of said structure in said signal path and the distance separating said component of said structure in said signal path and the nearest structure thereto in said selected conductor layer.
Claim 45
Dependent Claim
16 words
A method as in claim 39, wherein said selected conductor layer is a substrate conductor layer.
Claim 46
Dependent Claim
48 words
A method as in claim 43, wherein said capacitance coupling is characterized by a dimension of said component of said structure in said signal path and the distance separating said component of said structure in said signal path and the nearest structure thereto in said selected conductor layer.
Claim 47
Dependent Claim
24 words
A method as in claim 39, wherein said structure in said signal path is in a different conductor layer than said selected conductor layer.
Claim 48
Dependent Claim
34 words
A method as in claim 45, wherein said interconnect primitive is further identified according to bins, each bin representing a predetermined range of distances from said component of said structure in said signal path.
Claim 49
Dependent Claim
33 words
A method as in claim 46, wherein said predetermined range of distances is process-specific and wherein said bins are characterized by a dimension of said component of said structure in said signal path.
Claim 50
Dependent Claim
23 words
A method as in claim 46, wherein said network extraction tool estimates said coupling capacitance by interpolating between interconnect primitives of neighboring bins.
Claim 51
Dependent Claim
22 words
A method as in claim 48, wherein said interpolating step includes using a function which diminishes with distance more rapidly than linearly.
Claim 52
Dependent Claim
34 words
A method as in claim 46, wherein said network extraction tool estimates said capacitance coupling taking into consideration the extent to which said structure in said selected conductor layer is present in each bin.
Claim 53
Dependent Claim
30 words
A method as in claim 45, wherein a selected surface of said structure in said selected conductor layer has a major extent in a direction orthogonal to said signal path.
Claim 54
Dependent Claim
21 words
A method as in claim 45, wherein said component of said structure in said selected conductor layer includes an edge thereof.
Claim 55
Dependent Claim
33 words
A method as in claim 52, wherein said capacitance coupling is characterized by a distance between said component in said selected conductor layer and its nearest neighboring structure in said selected conductor layer.
Claim 56
Dependent Claim
31 words
A method as in claim 45, wherein said component of said structure in said selected conductor layer is a surface oriented towards said component of said structure in said signal path.
Claim 57
Dependent Claim
32 words
A method as in claim 45, wherein said component of said structure in said selected conductor layer comprises a surface oriented away from said component of said structure in said signal path.
Claim 58
Dependent Claim
25 words
A method as in claim 45, wherein said interconnect primitive is characterized by a dimension of said component of said structure in said signal path.
Claim 59
Dependent Claim
42 words
A method as in claim 45, wherein said interconnect primitive is characterized by a spacing between said component of said structure in said signal path and the nearest structure thereto in the same conductor layer as said structure in said signal path.
Claim 60
Dependent Claim
24 words
A method as in claim 39, wherein said network extraction tool provides a capacitor in said electrical network model to represent said interconnect primitive.
Claim 61
Dependent Claim
30 words
A method as in claim 38, wherein said network extraction tool divides said structures into change areas, each change area representing a change in dimension in one of said structures.
Claim 62
Dependent Claim
50 words
A method as in claim 38, wherein said network extractor tool divides said signal path into a right portion and a left portion along a direction of signal propagation in said signal path, said network extraction tool analyzing structures in said right portion independently of structures in said left portion.
Claim 63
Dependent Claim
41 words
A method as in claim 38, wherein said network extraction tool analyzes coupling between a structure in a conductor layer of said signal path and a structure in a selected conductor layer other than said conductor layer of said signal path.
Claim 64
Dependent Claim
54 words
A method as in claim 61, wherein said network extraction tool selects a said selected conductor layer one at a time from a plurality of conductor layers in increasing order of a distance from said structure in said conductor layer of said signal path, taking into account shielding effects of conductor layers already selected.
Claim 65
Dependent Claim
79 words
A method as in claim 62, wherein said network extraction tool separately takes into account (i) shielding effects arising from capacitance coupling between said structure in said conductor layer of said signal path and structures in conductor layers on the same side of said selected conductor layer, and (ii) shielding effects arising from capacitance coupling between said structure in said conductor layer of said signal path and structures in conductor layers on opposite sides of said selected conductor layer.
Claim 66
Dependent Claim
23 words
A method as in claim 38, wherein each interconnect primitive is identified, in part, in said interconnect primitive library by a conductor layer.
Claim 67
Dependent Claim
31 words
A method as in claim 38, wherein said structures include vias, and wherein said network extraction tool provides in said electrical network model a resistor to represent each of said vias.
Claim 68
Dependent Claim
37 words
A method as in claim 38, further comprising an interconnect primitive library building tool, said interconnect library building tool assembling said interconnect primitive library using said values of said physical parameters and an electric field distribution solver.
Claim 69
Dependent Claim
20 words
A method as in claim 38, wherein said physical parameters include resistivity for each conductor layer in said fabrication process.
Claim 70
Dependent Claim
16 words
A method as in claim 38, wherein said physical parameters include a resistance for a via.
Claim 71
Dependent Claim
25 words
A method as in claim 38, wherein said network extraction tool traces said signal path along polygons in a conductor layer of said signal path.
Claim 72
Dependent Claim
27 words
A method as in claim 38, wherein said network extraction tool is configurable to trace said signal path up to terminals of transistors of said integrated circuit.
Claim 73
Dependent Claim
30 words
A method as in claim 38, wherein said network extraction tool is configurable to trace said signal path up to a pin of a macro cell of said integrated circuit.
Claim 74
Dependent Claim
41 words
A method as in claim 38, wherein said network extraction tool provides in said electrical network model, for each structure in a selected type of structure in said signal path, a "pi" network to represent the parasitic impedances of said structure.
Claim 75
Dependent Claim
41 words
A method as in claim 38, wherein said network extraction tool provides in said electrical network model, for each structure of a selected type of structure in said signal path, a three-terminal network to represent the parasitic impedance of said structure.
Claim 76
Dependent Claim
32 words
A method as in claim 38, wherein said network extraction tool provides said electrical network model in a format suitable for use as an input file to a specified circuit simulation tool.
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