Feature optimization using enhanced interference mapping lithography

Claim 3

The method of optimizing an intensity profile according to claim 1 , wherein the mathematical expression generated in Step (b) is at least one eigenfunction representing certain characteristics of the optical system.

Claim 4

The method of optimizing an intensity profile according to claim 2 , wherein modifying the mathematical expression of Step (b) includes filtering the at least one eigenfunction.

Claim 5

The method of optimizing an intensity profile according to claim 3 , wherein the at least one eigenfunction is filtered relative to the sidelobes of the eigenfunction.

Claim 6

The method of optimizing an intensity profile according to claim 3 , wherein the at least one eigenfunction is filtered outside of the main lobe of the eigenfunction.

Claim 7

The method of optimizing an intensity profile according to claim 3 , wherein the filtering removes the DC component or certain low spatial frequencies of the eigenfunction.

Claim 8

The method of optimizing an intensity profile according to claim 3 , wherein the filtering enhances the eigenfunction for minimizing local imbalances of in-phase assist features and out-of-phase assist features generated in Step (e).

Claim 9

The method of optimizing an intensity profile according to claim 3 , wherein the interference map in Step (d) is generated by convolving the result of Step (a) with the result of Step (c).

Claim 10

The method of optimizing an intensity profile according to claim 1 , wherein step (e) includes selecting in-phase assist features and out-of-phase assist features corresponding to the interference map.

Claim 11

A program product, comprising executable code transportable by at least one machine readable medium, wherein execution of the code by at least one programmable computer causes the at least one programmable computer to perform a sequence of steps for optimizing an intensity profile of a pattern to be formed in a surface of a substrate for a given mask utilizing an optical system, compromising: (a) mathematically representing a goal function representing desired printing behavior of the given mask; (b) generating a mathematical expression representing certain characteristics of the optical system; (c) modifying the mathematical expression of Step (b); (d) generating an interference map in accordance with the result of Step (c) and Step (a); and (e) determining assist features for the given mask based on the interference map of Step (d), wherein modifying the mathematical expression of Step (b) minimizes undesired printing in the surface of the substrate.

Claim 12

A program product, comprising executable code transportable by at least one machine readable medium, wherein execution of the code by at least one programmable computer causes the at least one programmable computer to perform a sequence of steps for optimizing an intensity profile of a pattern to be formed in a surface of a substrate for a given mask utilizing an optical system, compromising: (a) mathematically representing a goal function representing desired printing behavior of the given mask; (b) generating a mathematical expression representing certain characteristics of the optical system; (c) modifying the mathematical expression of Step (b); (d) generating an interference map in accordance with the result of Step (c) and Step (a); and (e) determining assist features for the given mask based on the interference map of Step (d), wherein modifying the mathematical expression of Step (b) minimizes undesired printing in the surface of the substrate.

Claim 13

The method of optimizing an intensity profile according to claim 10 , wherein the mathematical expression generated in Step (b) is at least one eigenfunction representing certain characteristics of the optical system.

Claim 14

The method of optimizing an intensity profile according to claim 11 , wherein modifying the mathematical expression of Step (b) includes filtering the at least one eigenfunction.

Claim 15

The method of optimizing an intensity profile according to claim 12 , wherein the at least one eigenfunction is filtered relative to the sidelobes of the eigenfunction.

Claim 16

The method of optimizing an intensity profile according to claim 12 , wherein the at least one eigenfunction is filtered outside of the main lobe of the eigenfunction.

Claim 17

The method of optimizing an intensity profile according to claim 12 , wherein the filtering removes the DC component or certain low spatial frequencies of the eigenfunction.

Claim 18

The method of optimizing an intensity profile according to claim 12 , wherein the filtering enhances the eigenfunction for minimizing local imbalances of in-phase assist features and out-of-phase assist features generated in Step (e).

Claim 19

The method of optimizing an intensity profile according to claim 12 , wherein the interference map in Step (d) is generated by convolving the result of Step (a) with the result of Step (c).

Claim 20

The method of optimizing an intensity profile according to claim 10 , wherein step (e) includes selecting in-phase assist features an out-of-phase assist features corresponding to the interference map.

Claim 23

The method of optimizing an intensity profile according to claim 19 , wherein the mathematical expression generated in Step (c) is at least one eigenfunction representing certain characteristics of the optical system.

Claim 24

The method of optimizing an intensity profile according to claim 20 , wherein modifying the mathematical expression of Step (c) includes filtering the at least one eigenfunction.

Claim 25

The method of optimizing an intensity profile according to claim 21 , wherein the at least one eigenfunction is filtered relative to the sidelobes of the eigenfunction.

Claim 26

The method of optimizing an intensity profile according to claim 21 , wherein the at least one eigenfunction is filtered outside of the main lobe of the eigenfunction.

Claim 27

The method of optimizing an intensity profile according to claim 21 , wherein the filtering removes the DC component or certain low spatial frequencies of the eigenfunction.

Claim 28

The method of optimizing an intensity profile according to claim 21 , wherein the filtering enhances the eigenfunction for minimizing local imbalances of in-phase assist features and out-of-phase assist features generated in Step (f).

Claim 29

The method of optimizing an intensity profile according to claim 21 , wherein the interference map in Step (e) is generated by convolving the result of Step (b) with the result of Step (d).

Claim 30

The method of optimizing an intensity profile according to claim 20 , wherein step (f) includes selecting in-phase assist features and out-of-phase assist features corresponding to the interference map.