Method, program product and apparatus for obtaining short-range flare model parameters for lithography simulation tool

• US 20070260437A1
• Filed: 05/02/2006
• Published: 11/08/2007
• Est. Priority Date: 05/02/2006
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Masktools B.V. (ASML Holding NV)
• Inventors: Coskun, Tamer, Park, Sangbong, Geh, Bernd, Chen, Jang
• Granted Patent: US 7,818,151 B2
• Time in Patent Office: Days
• US Class Current: 703/6
• CPC Class Codes: G03F 7/705 Modelling or simulating from physical phenomena up to complete wafer processes or whole workflow in wafer productions
• CPC Class Codes: G03F 7/70941 Stray fields and charges, e.g. stray light, scattered light, flare, transmission loss

Abstract

A process of obtaining short-range flare model parameters representing a short-range flare which degrades a contrast of an image generated by a lithography tool, is disclosed. Short-range flare is measured from the image to obtain measured short-range flare data. A simulation is performed based on short-range flare model parameters to obtain simulated short-range flare data. The simulated short-range flare data is compared with the measured short range flare data. It is determined whether the short-range flare model parameters used in the simulation is appropriate based on the comparison result. The short-range flare model parameters is optimized according to the measured short-range data and the simulated short-range flare data if the short-range flare model parameters used for the simulation is not appropriate.

Claims

1. A method of obtaining short-range flare model parameters representing a short-range flare which degrades a contrast of an image generated by a lithography tool, comprising the steps of:

measuring short-range flare from the image to obtain measured short-range flare data;

performing a simulation based on short-range flare model parameters to obtain simulated short-range flare data;

comparing the simulated short-range flare data with the measured short range flare data;

determining whether the short-range flare model parameters used in the simulation is appropriate based on the comparison result; and

optimizing the short-range flare model parameters according to the measured short-range data and the simulated short-range flare data if the short-range flare model parameters used for the simulation is not appropriate.

2. The method according to claim 1, wherein the step of measuring short-range flare utilizes one of a disappearing box test and a sensor based test.

3. The method according to claim 1, wherein the step of performing the simulation includes the steps of

providing initial short-range flare model parameters for the first time of the simulation, and

performing the simulation based on the initial short-range flare model parameters to generate initial simulated short-range flare data for comparison with the measured short-range flare data.

4. The method according to claim 1, wherein the step of optimizing utilizes a genetic algorithm to generate new set of the short-range flare model parameters based on the measured short-range data and the simulated short-range flare data, and provides the new set of the short-range flare model parameters to the step of performing the simulation.

5. A method for performing a lithography simulation, comprising the steps of:

obtaining optimized short-range flare model parameters according to claim 1;

and

performing a lithography simulation in consideration of the optimized short-range flare model parameters.

6. A method for performing a lithography simulation, comprising the steps of:

obtaining optimized short-range flare model parameters for a reference lithography system according to claim 1;

and

performing proximity matching to match the Optical Proximity Effect (OPE) of a given a lithography system to the OPE of the reference lithography system in consideration of the optimized short-range flare model.

7. A computer program product having a computer readable medium bearing a computer program for obtaining short-range flare model parameters representing a short-range flare which degrades a contrast of an image generated by a lithography tool, the computer program, when executed, causing a computer to perform the steps of:

measuring short-range flare from the image to obtain measured short-range flare data;

performing a simulation based on short-range flare model parameters to obtain simulated short-range flare data;

comparing the simulated short-range flare data with the measured short range flare data;

determining whether the short-range flare model parameters used in the simulation is appropriate based on the comparison result; and

optimizing the short-range flare model parameters according to the measured short-range data and the simulated short-range flare data if the short-range flare model parameters used for the simulation is not appropriate.

8. The computer program product according to claim 7, wherein the step of measuring short-range flare utilizes one of a disappearing box test and a sensor based test.

9. The computer program product according to claim 7, wherein the step of performing the simulation includes the steps of

providing initial short-range flare model parameters for the first time of the simulation, and

performing the simulation based on the initial short-range flare model parameters to generate initial simulated short-range flare data for comparison with the measured short-range flare data.

10. The computer program product according to claim 7, wherein the step of optimizing utilizes a genetic algorithm to generate new set of the short-range flare model parameters based on the measured short-range data and the simulated short-range flare data, and provides the new set of the short-range flare model parameters to the step of performing the simulation.

11. An apparatus for obtaining short-range flare model parameters representing a short-range flare which degrades a contrast of an image generated by a lithography tool, the apparatus comprising:

a first unit configured for measuring short-range flare from the image to obtain measured short-range flare data;

a second unit configured for performing a simulation based on short-range flare model parameters to obtain simulated short-range flare data;

a third unit configured for comparing the simulated short-range flare data with the measured short range flare data;

a fourth unit configured for determining whether the short-range flare model parameters used in the simulation is appropriate based on the comparison result; and

a fifth unit configured for optimizing the short-range flare model parameters according to the measured short-range data and the simulated short-range flare data if the short-range flare model parameters used for the simulation is not appropriate.

12. The apparatus according to claim 11, wherein the first unit utilizes one of a disappearing box test and a sensor based test to measure the short-range flare.

13. The apparatus according to claim 11, wherein the second unit is further configured for receiving initial short-range flare model parameters for the first time of the simulation, and performing the simulation based on the initial short-range flare model parameters to generate initial simulated short-range flare data for comparison with the measured short-range flare data.

14. The apparatus according to claim 11, wherein the fifth unit utilizes a genetic algorithm to generate new set of the short-range flare model parameters based on the measured short-range data and the simulated short-range flare data, and provides the new set of the short-range flare model parameters to the second unit.