Accurate approximation of resistance in a wire with irregular biasing and determination of interconnect capacitances in VLSI layouts in the presence of Catastrophic Optical Proximity Correction

1. An apparatus for calculating an approximate electrical performance value for a target wire shape, having a left neighbor and a right neighbor shape in a chip, when using a Design Automated Application (DA application) that is limited to determining one of two possible distances to a neighbor wire shape of the target wire shape at any one time, comprising:

a computer connected to a memory and to a database; and

a DA application and a Bias Calculation (BC) program in the memory;

wherein the BC program contains a plurality of instructions to cause a processor of the computer to interact with the DA application and to:

pass a scanline over the target wire shape to generate data;

determine from the data, a first separation distance from the left neighbor;

responsive to determining the first separation distance, biasing a width of the target wire shape symmetrically using the first separation distance to determine a first bias width;

calculate, using the first bias width, a first electrical performance value for the target wire shape;

determine, from the data, a second separation distance from the right neighbor;

responsive to determining the second separation distance, bias the width of the target wire shape symmetrically using the second separation distance to determine a second bias width;

calculate, using the second bias width, a second electrical performance value for the target wire shape;

calculate the approximate electrical performance value by averaging the first value and the second value to obtain the approximate electrical performance value; and

using the approximate electrical performance value to validate a design specification of the chip.

2. The apparatus of claim 1 , when the electrical performance value is a resistance value, the plurality of instructions are adapted to cause the processor to perform steps comprising:

determining a first spacing-dependent full bias for a first side using a plurality of separations for one or more first side neighbor wire shapes, and using the first spacing-dependent full bias, computing a first target wire shape resistance;

determining a second spacing-dependent full bias for a second side using a plurality of second separations for one or more second side neighbor wire shapes, and using the second spacing-dependent full bias to compute a second target wire shape resistance;

calculating an approximate resistance value by averaging the first resistance value and the second resistance value; and

using the approximate resistance value for a design validation.

3. The apparatus of claim 1 , wherein when the electrical performance value is a capacitance value, the plurality of instructions are adapted to cause the processor to perform steps comprising:

calculating a first biased target wire shape capacitance by determining a first lateral capacitance, a first layer capacitance, and a second layer capacitance of a first neighbor on a first side of the target wire shape using a target wire shape width corrected with a first spacing-dependent full bias;

calculating a second biased target wire shape capacitance by determining a second lateral capacitance, a third layer capacitance to the first layer shape, and a fourth layer capacitance to the second layer shape of a second neighbor on a second side of the target wire shape using a second target wire shape width corrected with a second spacing-dependent full bias;

averaging the first layer capacitance, the second layer capacitance, the third layer capacitance and the fourth layer capacitance to get an approximate layer capacitance value;

averaging the first lateral capacitance value and the second lateral capacitance value to get an approximate lateral capacitance value; and

using the sum of the approximate layer capacitance value and the approximate lateral capacitance value for design validation.

4. The apparatus of claim 1 , further comprising:

wherein a plurality of first order errors cancel.

5. The apparatus of claim 1 , further comprising:

wherein the approximate electrical value is calculated without an impact on a consumption of a memory or a performance resource caused by a simultaneous calculation of a full bias for both the first side and the second side of the target wire shape.

6. A computer implemented method comprising:

loading a Bias Calculation program (BC program) into a memory connected to a computer, the memory containing a Design Automated Software Application (DA application), the DA application limited to determining one of two possible distances to a neighbor wire shape of a target wire shape at any one time;

using the BC program, interfacing with the DA application, and causing a processor of the computer to perform steps comprising:

passing a scanline over the target wire shape to generate data;

determining from the data, a first separation distance from the left neighbor;

responsive to determining the first separation distance, biasing a width of the target wire shape symmetrically using the first separation distance to determine a first bias width;

calculating, using the first bias width, a first electrical performance value for the target wire shape;

determining, from the data, a second separation distance from the right neighbor;

responsive to determining the second separation distance, biasing the width of the target wire shape symmetrically using the second separation distance to determine a second bias width;

calculating, using the second bias width, a second electrical performance value for the target wire shape;

calculating an approximate electrical performance value for the target wire shape, by averaging the first electrical performance value and the second electrical performance value to obtain the approximate electrical performance value; and

using the approximate electrical performance value to validate a design specification of a chip.

7. The computer implemented method of claim 6 , further comprising:

when the electrical performance value is a resistance value, causing the processor to perform steps comprising:

determining a first spacing-dependent full bias for a first side using a plurality of separations for one or more first side neighbor wire shapes, and using the first spacing-dependent full bias, computing a first target wire shape resistance;

determining a second spacing-dependent full bias for a second side using a plurality of second separations for one or more second side neighbor wire shapes, and using the second spacing-dependent full bias to compute a second target wire shape resistance;

calculating an approximate resistance value by averaging the first resistance value and the second resistance value; and

using the approximate resistance value for a design validation.

8. The computer implemented method of claim 6 , wherein when the electrical performance value is a capacitance value, causing the computer to perform steps comprising:

calculating a first biased target wire shape capacitance by determining a first lateral capacitance, a first layer capacitance, and a second layer capacitance of a first neighbor on a first side of the target wire shape using a target wire shape width corrected with a first spacing-dependent bias;

calculating a second biased target wire shape capacitance by determining a second lateral capacitance, a third layer capacitance to the first layer shape, and a fourth layer capacitance to the second layer shape of a second neighbor on a second side of the target wire shape using a second target wire shape width corrected with a second spacing-dependent full bias;

averaging the first layer capacitance, the second layer capacitance, the third layer capacitance and the fourth layer capacitance to get an approximate layer capacitance value;

averaging the first lateral capacitance value and the second lateral capacitance value to get an approximate lateral capacitance value; and

using the sum of the approximate layer capacitance value and the approximate lateral capacitance value for design validation.

9. The computer implemented method of claim 6 , further comprising:

wherein a plurality of first order errors cancel.

10. The computer implemented method of claim 6 , further comprising:

wherein the approximate electrical value is calculated without an impact on a consumption of a memory or a performance resource caused by a simultaneous calculation of a full bias for both the first side and the second side of the target wire shape.

11. A computer program product comprising:

a non-transitory computer readable storage device, the computer readable storage device containing a plurality of instructions configured to cause a computer to perform steps comprising:

interfacing with a Design Automated Software Application (DA application) that is limited to determining one of two possible distances to a neighbor wire shape of the target wire shape at any one time;

passing a scanline over the target wire shape to generate data;

determining from the data, a first separation distance from the left neighbor;

responsive to determining the first separation distance, biasing a width of the target wire shape symmetrically using the first separation distance to determine a first bias width;

calculating, using the first bias width, a first electrical performance value for the target wire shape;

determining, from the data, a second separation distance from the right neighbor;

responsive to determining the second separation distance, biasing the width of the target wire shape symmetrically using the second separation distance to determine a second bias width;

calculating, using the second bias width, a second electrical performance value for the target wire shape; and

using the approximate electrical performance value to validate a design specification of a chip.

12. The computer program product of claim 11 , further comprising:

when the electrical performance value is a resistance value, causing the processor to perform steps comprising:

determining a first spacing-dependent full bias for a first side using a plurality of separations for one or more first side neighbor wire shapes, and using the first spacing-dependent full bias, computing a first target wire shape resistance;

determining a second spacing-dependent full bias for a second side using a plurality of second separations for one or more second side neighbor wire shapes, and using the second spacing-dependent full bias to compute a second target wire shape resistance;

calculating an approximate resistance value by averaging the first resistance value and the second resistance value; and

using the approximate resistance value for a design validation.

13. The computer program product of claim 11 , wherein when the electrical performance value is a capacitance value, causing the computer to perform steps comprising:

calculating a first biased target wire shape capacitance by determining a first lateral capacitance, a first layer capacitance, and a second layer capacitance of a first neighbor on a first side of the target wire shape using a target wire shape width corrected with a first spacing-dependent bias;

calculating a second biased target wire shape capacitance by determining a second lateral capacitance, a third layer capacitance to the first layer shape, and a fourth layer capacitance to the second layer shape of a second neighbor on a second side of the target wire shape using a second target wire shape width corrected with a second spacing-dependent full bias;

averaging the first layer capacitance, the second layer capacitance, the third layer capacitance and the fourth layer capacitance to get an approximate layer capacitance value;

averaging the first lateral capacitance value and the second lateral capacitance value to get an approximate lateral capacitance value; and

using the sum of the approximate layer capacitance value and the approximate lateral capacitance value for design validation.

14. The computer program product of claim 11 , further comprising:

wherein a plurality of first order errors cancel.

15. The computer program product of claim 11 , further comprising:

wherein the approximate electrical value is calculated without an impact on a consumption of a memory or a performance resource caused by a simultaneous calculation of a full bias for both the first side and the second side of the target wire shape.