Cell generation method and cell generation system
First Claim
1. A method of generating cells for a semiconductor integrated circuit, said method comprising the steps of:
- (a) determining locations of transistors in a cell;
(b) finding wire routings between said transistors on a gridded plane; and
(c) performing a compaction process on a placement/wiring result on said gridded plane;
said step (a) including;
(a-1) initializing a grouping of transistors, said grouping being arranged in accordance with diffusion sharing;
(a-2) modifying said grouping;
(a-3) finding locations of transistors in said modified grouping;
(a-4) evaluating said locations found at said step (a-3); and
(a-5) making a judgment of whether to accept said locations found at said step (a-3) according to said evaluation made at said step (a-4).
1 Assignment
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Accused Products
Abstract
Densely-packed leaf cells for semiconductor integrated circuits are generated. The placement of transistors in a leaf cell is determined, and wire routings between the transistors are found on a gridded plane, and a compaction operation is performed on a placement/wiring result on the gridded plane. More specifically, locations of transistors in a leaf cell are determined (i) by a step of initializing a transistor grouping arranged in accordance with diffusion sharing, (ii) by a step of modifying the transistor grouping, (iii) by a step of finding locations of transistor in the modified transistor grouping, (iv) by a step of evaluating a result of the step (iii); and (v) by a step of making a judgment of whether to accept a result of step (iii) according to a result of step (iv).
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Citations
16 Claims
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1. A method of generating cells for a semiconductor integrated circuit, said method comprising the steps of:
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(a) determining locations of transistors in a cell; (b) finding wire routings between said transistors on a gridded plane; and (c) performing a compaction process on a placement/wiring result on said gridded plane; said step (a) including; (a-1) initializing a grouping of transistors, said grouping being arranged in accordance with diffusion sharing; (a-2) modifying said grouping; (a-3) finding locations of transistors in said modified grouping; (a-4) evaluating said locations found at said step (a-3); and (a-5) making a judgment of whether to accept said locations found at said step (a-3) according to said evaluation made at said step (a-4). - View Dependent Claims (2)
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3. A semiconductor integrated circuit arranged with densely-packed leaf cells comprising:
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a plurality of transistors adjacent to each other in a vertical direction, wherein said plurality of transistors are spaced apart from one another to achieve a space-saving cell layout design and arranged in groupings to provide a diffusion sharing; a plurality of vertical and horizontal wire routing regions located between said transistors comprising channel graphs thereby forming a gridded plane, said vertical and horizontal wire routing regions comprising laminated interconnection layers; and a plurality of contacts connecting said interconnection layers.
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4. A method of generating cells for a semiconductor integrated circuit, said method comprising the steps of:
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(a) determining locations of transistors in a cell; (b) finding wire routings between said transistors on a gridded plane; and (c) performing a compaction process on a placement/wiring result on said gridded plane; said step (b) including; (b-1) arranging a grid structure having a plurality of grid vertexes and a plurality of grid edges; (b-2) giving a detour wire routing length equivalent to generation of one contact; (b-3) finding a shortest distance from a starting point located at each said grid vertex to a target point; (b-4) initializing a detour distance to zero; (b-5) when no wire routings are found within a wire routing length range defined by a sum of said shortest distance and said detour distance, increasing said detour distance by one and searching an interconnection layer for a wire routing which goes through some of said plurality of grid edges from said starting point to said target point and which goes around an existing interconnection line; and (b-6) when said increased detour distance exceeds said given detour wire routing length, generating one contact and searching a different interconnection layer for a wire routing which goes through some of said plurality of grid edges from said starting point to said target point and which jumps over said existing interconnection line. - View Dependent Claims (5)
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6. A semiconductor integrated circuit arranged with densely-packed leaf cells comprising:
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a plurality of transistors adjacent to each other in a vertical direction, wherein said plurality of transistors are spaced apart from one another to achieve a space-saving cell layout design and arranged in groupings to provide a diffusion sharing; a plurality of vertical and horizontal wire routing regions located between said transistors comprising channel graphs thereby forming a gridded plane, said vertical and horizontal wire routing regions comprising laminated interconnection layers; a plurality of contacts connecting said interconnection layers; and a detour wire having a routing length to provide a contact disposed between said routing regions, wherein said groupings are arranged in a graph in which said transistors correspond to respective graph edges, wherein nets correspond to respective graph vertexes, and wherein at least one of said graph vertexes has a share state of a transistor in a corresponding net.
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7. A method of generating cells for a semiconductor integrated circuit, said method comprising the steps of:
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(a) determining locations of transistors in a cell; (b) finding wire routings between said transistors on a gridded plane; and (c) performing a compaction process on a placement/wiring result on said gridded plane; said step (c) including; (c-1) assigning inter-transistor position constraints; (c-2) finding, based on said position constraints, a cluster of transistors capable of being under-packed; (c-3) arranging a gridded plane to supreme forms of existing placement components; (c-4) shifting each transistor belonging to said cluster on said gridded plane such that each said transistor is underpacked as low as possible; (c-5) re-routing said transistors belonging to said cluster on said gridded plane; and (c-6) under-packing said transistors belonging to said cluster and interconnection lines thereof such that said transistors and said interconnection lines are under-packed as low as possible towards said existing placement components.
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8. A semiconductor integrated circuit arranged with densely-packed leaf cells comprising:
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a plurality of transistors adjacent to each other in a vertical direction, wherein said plurality of transistors are spaced apart from one another to achieve a space-saving cell layout design and arranged in groupings to provide a diffusion sharing; a plurality of vertical and horizontal wire routing regions located between said transistors comprising channel graphs thereby forming a gridded plane, said vertical and horizontal wire routing regions comprising laminated interconnection layers; a plurality of contacts connecting said interconnection layers; and a cluster of transistors comprising a plurality of said plurality of transistors, wherein each transistor in a cluster of transistors is underpacked as low as possible.
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9. An apparatus for generating cells for a semiconductor integrated circuit, said apparatus comprising:
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(a) means for determining locations of transistors in a cell; (b) means for finding wire routings between said transistors on a gridded plane; and (c) means for performing a compaction process on a placement/wiring result on said gridded plane; said means (a) including; (a-1) means for initializing a grouping of transistors, said grouping being arranged in accordance with diffusion sharing; (a-2) means for modifying said grouping; (a-3) means for finding locations of transistors in said modified grouping; (a-4) means for evaluating said locations found by said means (a-3); and (a-5) means for making a judgment of whether to accept said locations found by said means (a-3) according to said evaluation made by said means (a-4).
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10. An apparatus for generating cells for a semiconductor integrated circuit, said apparatus comprising:
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(a) means for determining locations of transistors in a cell; (b) means for finding wire routings between said transistors on a gridded plane; and (c) means for performing a compaction process on a placement/wiring result on said gridded plane; said means (b) including; (b-1) means for arranging a grid structure having a plurality of grid vertexes and a plurality of grid edges; (b-2) means for giving a detour wire routing length equivalent to generation of one contact; (b-3) means for finding a shortest distance from a starting point located at each said grid vertex to a target point; (b-4) means for initializing a detour distance to zero; (b-5) means for, when no wire routings are found within a wire routing length range defined by a sum of said shortest distance and said detour distance, increasing said detour distance by one and searching an interconnection layer for a wire routing which goes through some of said plurality of grid edges from said starting point to said target point and which goes around an existing interconnection line; and (b-6) means for, when said increased detour distance exceeds said given detour wire routing length, generating one contact and searching a different interconnection layer for a wire routing which goes through some of said plurality of grid edges from said starting point to said target point and which jumps over said existing interconnection line.
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11. An apparatus for generating cells for a semiconductor integrated circuit, said apparatus comprising:
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(a) means for determining locations of transistors in a cell; (b) means for finding wire routings between said transistors on a gridded plane; and (c) means for performing a compaction process on a placement/wiring result on said gridded plane; said means (c) including; (c-1) means for assigning inter-transistor position constraints; (c-2) means for finding, based on said position constraints, a cluster of transistors capable of being under-packed; (c-3) means for arranging a gridded plane to supreme forms of existing placement components; (c-4) means for shifting each transistor belonging to said cluster on said gridded plane such that each said transistor is under-packed as low as possible; (c-5) means for re-routing said transistors belonging to said cluster on said gridded plane; and (c-6) means for under-packing said transistors belonging to said cluster and interconnection lines thereof such that said transistors and said interconnection lines are under-packed as low as possible towards said existing placement components.
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12. A method of determining locations of transistors in a cell for a semiconductor integrated circuit, said method comprising the steps of:
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(a) initializing a grouping of transistors, said grouping being arranged in accordance with diffusion sharing; (b) modifying said grouping; (c) finding locations of transistors in said modified grouping; (d) evaluating said locations found at said step (c); and (e) making a judgment of whether to accept said locations found at said step (c) according to said evaluation made at said step (d). - View Dependent Claims (13)
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14. A method of finding a wire routing in a semiconductor integrated circuit, said method comprising the steps of:
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(a) arranging a grid structure having a plurality of grid vertexes and a plurality of grid edges; (b) giving a detour wire routing length equivalent to generation of one contact; (c) finding a shortest distance from a starting point located at each said grid vertex to a target point; (d) initializing a detour distance to zero; (e) when no wire routings are found within a wire routing length range defined by a sum of said shortest distance and said detour distance, increasing said detour distance by one and searching an interconnection layer for a wire routing which goes through some of said plurality of grid edges from said starting point to said target point and which goes around an existing interconnection line; and (f) when said increased detour distance exceeds said given detour wire routing length, generating one contact and searching a different interconnection layer for a wire routing which goes through some of said plurality of grid edges from said starting point to said target point and which jumps over said existing interconnection line. - View Dependent Claims (15)
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16. A method of performing compaction for semiconductor integrated circuits, said method comprising the steps of:
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(a) assigning inter-placement component position constraints; (b) finding, based on said position constraints, a cluster of placement components capable of being under-packed; (c) arranging a gridded plane to the supreme form of existing placement components; (d) shifting each placement component belonging to said cluster on said gridded plane such that each said placement component is under-packed as low as possible; (e) re-routing said placement components belonging to said cluster on said gridded plane; and (f) under-packing said placement components belonging to said cluster and interconnection lines thereof such that said placement components and said interconnection lines are under-packed as low as possible towards said existing placement components.
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Specification