Method of computer-assisted design of integrated circuit chips, and library of delay time values for computer-assisted design of such chips

1. A computer-assisted design method of placing a plurality of integrated circuit chips on a semiconductor wafer, said method comprising:

exposing each of a plurality of unit areas on the semiconductor wafer to a beam of radiation to form logic gates thereon;

detecting, from each of the exposed areas, a plurality of exposure-dependent delay time values representing delay times associated with interconnections of the logic gates, the delay times resulting from physical factors of said beam at a plurality of different positions within such exposed area;

storing the detected exposure-dependent delay time values in a library; and

calculating a propagation delay time associated with the exposed areas based on the delay time values of logic gates in said library.

2. The computer-assisted design method of claim 1 , wherein:

the unit areas are exposed by simultaneously exposing a plurality of integrated circuit chips within each of said unit areas to said beam of radiation, and

said exposure-dependent delay time values depend on relative positions of the exposed integrated circuit chips within said unit area.

3. The computer-assisted design method of claim 2 , wherein said exposure-dependent delay time values are detected by detecting exposure-dependent delay time values of capacitive load components associated with interconnections between logic gates.

4. The computer-assisted design method of claim 1 , wherein:

the unit areas are exposed by exposing only one integrated circuit chip within each of said unit areas, and

each of said exposure-dependent delay time values comprises a function of position within the exposed integrated circuit chip.

5. The computer-assisted design method of claim 1 , wherein:

the unit areas are exposed by exposing only one integrated circuit chip within each of said unit areas, and

each of said exposure-dependent delay time values comprises a function of distance from the center of an associated unit area to the exposed integrated circuit chip.

6. The computer-assisted design method of claim 1 , wherein storing the detected exposure-dependent delay time values comprises storing a plurality of chip-position dependent delay time values in said library.

7. The computer-assisted design method of claim 1 , wherein storing the detected exposure-dependent delay time values comprises storing a plurality of delay time values of a random component in said library.

8. The computer-assisted design method of claim 1 , wherein storing the detected exposure-dependent delay time values comprises adding to said library a plurality of chip-position dependent delay time values and a plurality of delay time values of a random component.

9. The computer-assisted design method of claim 8 , wherein storing the detected exposure-dependent delay time values comprises:

detecting a plurality of device parameters from a plurality of groups of test chips, the test chips of each group being located in an identical position on a plurality of semiconductor wafers;

calculating average values of said device parameters respectively detected from said groups of test chips to produce said chip-position dependent delay time values; and

calculating a plurality of differences between said device parameters and said average values to produce said delay time values of a random component.

10. The computer-assisted design method of claim 8 , further comprising storing in said library delay time values of capacitive load components associated with interconnections between logic gates.

11. A method of creating a library of delay time values for computer-assisted design of integrated circuit chips, said method comprising:

detecting a plurality of device parameters from a plurality of groups of test chips having logic gates thereon, the test chips of each of the groups being formed at an identical position on a plurality of test wafers;

calculating an average value of said device parameters detected from each of said groups of test chips to produce a plurality of chip-position dependent delay time values for a plurality of said logic gates;

calculating a plurality of differences between said device parameters and said average value to produce a plurality of delay time values of a random component for said logic gates;

successively exposing a plurality of unit areas of a test wafer to a beam of radiation, each of said unit areas containing at least one test chip;

detecting, from each of said exposed unit areas, a plurality of exposure-dependent delay time values for said logic gates, representing delay times resulting from physical factors of said beam at a plurality of different positions within such exposed area; and

storing said chip-position dependent delay time values, said delay time values of a random component, and said exposure-dependent delay time values in the library.

12. The method of claim 11 , further comprising:

detecting a plurality of device parameters from the test chips of said exposed unit areas to produce a plurality of exposure-dependent delay time values of capacitive load components associated with interconnections between said logic gates; and

storing the exposure-dependent delay time values of capacitive load components in said library.

13. The method of claim 11 , further comprising:

calculating an average value of said exposure-dependent delay time values; and

storing the average value in said library.