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

• US 7,818,151 B2
• Filed: 05/02/2006
• Issued: 10/19/2010
• 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, Chen, Jang Fung, Geh, Bernd
• Primary Examiner(s): Craig; Dwin M
• Application Number:
  US11/415,423
• Publication Number:
  US 20070260437A1
• Time in Patent Office: 1,631 Days
• Field of Search: 703/2, 703/6, 716/4, 716 19- 21
• 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:

projecting radiation through a mask using the lithography tool to generate the image containing short-range flare;

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

generating a simulated image corresponding to the image generated by the lithography tool using 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

changing the values of the short-range flare model parameters used for generating the simulated image 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 changing the short-range flare model parameter values includes utilizing 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 providing 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. The method according to claim 1, wherein the optimized short-range flare model parameters are adapted to be incorporated into a power spectral density characterization that is used in a simulator for simulating the imaging performance of the lithographic tool and that is used to generate the simulated image.

8. The method according to claim 7, wherein the optimized short-range flare model parameters comprise ABC model parameters for the power spectral density characterization.

9. A computer program product comprising a computer readable storage 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:

receiving data corresponding to the image containing short-range flare which has been generated by projecting radiation through a mask using the lithography tool;

receiving measured short-range flare data that has been obtained by measuring the short-range flare in the image;

generating a simulated image corresponding to the image generated by the lithography tool using 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

changing the values of the short-range flare model parameters used for generating the simulated image 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.

10. The computer program product according to claim 9, wherein the step of measuring short-range flare utilizes one of a disappearing box test and a sensor based test.

11. The computer program product according to claim 9, 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.

12. The computer program product according to claim 9, wherein the step of changing the short-range flare model parameter values includes utilizing 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 providing the new set of the short-range flare model parameters to the step of performing the simulation.

13. 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, wherein the image containing the short-range flare is generated by projecting radiation through a mask using the lithography tool;

a second unit configured for generating a simulated image corresponding to the image generated by the lithography tool using 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 changing the values of the short-range flare model parameters used for generating the simulated image 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.

14. The apparatus according to claim 13, wherein the first unit utilizes one of a disappearing box test and a sensor based test to measure the short-range flare.

15. The apparatus according to claim 13, 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.

16. The apparatus according to claim 13, 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.