Layout method and layout apparatus for semiconductor integrated circuit

1. A layout method for a semiconductor integrated circuit by using cell library data, said method comprising:

arranging a plurality of cell patterns in a first direction, as executed by a computer;

specifying one of gate patterns in one of said plurality of cell patterns as a reference gate pattern; and

arranging an additional cell pattern in a second direction orthogonal to the first direction such that a number of gate patterns within a predetermined area comprising the reference gate pattern satisfies a constraint condition.

2. The layout method according to claim 1 , further comprising:

acquiring layout coordinates of gate patterns in each of said plurality of cell patterns,

wherein said arranging an additional cell pattern in a second direction comprises:

determining the predetermined area based on the acquired layout coordinates; and

determining the additional cell pattern to be arranged in the second direction such that the number of gate patterns within the predetermined area satisfies the constraint condition.

3. The layout method according to claim 2 , wherein said cell library data comprises layout coordinates of said gate patterns, and

wherein said acquiring comprises:

extracting the layout coordinates of said gate patterns from said cell library data.

4. The layout method according to claim 2 , wherein said acquiring further comprises:

using layout coordinates of diffusion layer patterns and layout coordinates of polysilicon gate patterns to calculate the layout coordinates of said gate patterns.

5. The layout method according to claim 4 , wherein said cell library data comprises the layout coordinates of the diffusion layer patterns and the layout coordinates of polysilicon gate patterns, and

wherein said acquiring comprises:

extracting the layout coordinates of the diffusion layer patterns and the layout coordinates of polysilicon gate patterns from said cell library data.

6. The layout method according to claim 1 , wherein said specifying comprises:

selecting the specified gate pattern arranged to be adjacent to a cell frame of the cell pattern, as the reference gate pattern.

7. The layout method according to claim 6 , wherein said specifying comprises:

selecting the specified gate pattern arranged at a corner in the cell pattern, as the reference gate pattern.

8. A layout apparatus, comprising:

a storage unit configured to store cell library data; and

an arrangement and wiring tool configured to arrange a plurality of cell patterns in a first direction, by using the cell library data,

wherein said arrangement & wiring tool comprises:

a reference gate specifying section configured to specify one of gate patterns in one of the plurality of cell patterns as a reference gate pattern; and

a layout section configured to arrange an additional cell pattern in a second direction orthogonal to the first direction such that a number of gate patters in a predetermined area comprising the reference gate pattern satisfies a constraint condition.

9. The layout apparatus according to claim 8 , wherein said arrangement and wiring tool further comprises a layout coordinates extracting section configured to acquire layout coordinates of the gate patterns in each of the plurality of cell patterns, and

said layout section determines the predetermined area based on the layout coordinates of the gate patterns, and arranges the additional cell pattern to be adjacent to the cell pattern in the second direction such that the number of gate patterns within the predetermined area satisfies the constraint condition.

10. The layout apparatus according to claim 9 , wherein said cell library data comprises layout coordinates of the gate patterns, and

wherein said layout coordinate extracting section extracts the layout coordinates of the gate patterns from said cell library data.

11. The layout apparatus according to claim 9 , wherein said layout coordinates extracting section calculates the layout coordinates of the gate patterns by using layout coordinates of diffusion layer patterns and layout coordinates of polysilicon gate patterns.

12. The layout apparatus according to claim 11 , wherein said cell library data comprises the layout coordinates of the diffusion layer patterns and the layout coordinates of the polysilicon gate patterns, and

wherein said layout coordinate extracting section extracts the layout coordinates of the diffusion layer patterns and the layout coordinates of the polysilicon gate patterns from said cell library data.

13. The layout apparatus according to claim 8 , wherein said reference gate specifying section selects the gate pattern arranged to be adjacent to a cell frame of the cell pattern, as the reference cell pattern.

14. The layout apparatus according to claim 13 , wherein said reference gate specifying section selects the gate pattern arranged at a corner in the cell pattern as the reference gate pattern.

15. A non-transitory computer-readable medium which stores instructions which when executed by a computer, cause the computer to realize a layout method for a semiconductor integrated circuit by using cell library data, said layout method comprising:

arranging a plurality of cell patterns in a first direction;

specifying one of gate patterns in one of said plurality of cell patterns as a reference gate pattern; and

arranging an additional cell pattern in a second direction orthogonal to the first direction such that a number of gate patterns within a predetermined area comprising the reference gate pattern satisfies a constraint condition.

16. The non-transitory computer-readable medium according to claim 15 , wherein the layout method further comprises:

acquiring layout coordinates of gate patterns in each of the plurality of cell patterns,

wherein said arranging an additional cell pattern in a second direction comprises:

determining the predetermined area based on the acquired layout coordinates; and

determining the additional cell pattern to be arranged in the second direction such that the number of gate patterns within the predetermined area satisfies the constraint condition.

17. The non-transitory computer-readable medium according to claim 16 , wherein said cell library data comprises layout coordinates of said gate patterns, and

wherein said acquiring comprises:

extracting the layout coordinates of said gate patterns from said cell library data.

18. The non-transitory computer-readable medium according to claim 16 , wherein said acquiring further comprises:

using layout coordinates of diffusion layer patterns and layout coordinates of polysilicon gate patterns to calculate the layout coordinates of said gate patterns.

19. The non-transitory computer-readable medium according to claim 18 , wherein said cell library data comprises the layout coordinates of diffusion layer patterns and the layout coordinates of polysilicon gate patterns, and

wherein said acquiring comprises:

extracting the layout coordinates of diffusion layer patterns and the layout coordinates of polysilicon gate patterns from said cell library data.