METHODS AND SYSTEMS FOR PATTERN DESIGN WITH TAILORED RESPONSE TO WAVEFRONT ABERRATION

• US 20150153651A1
• Filed: 12/18/2014
• Published: 06/04/2015
• Est. Priority Date: 07/08/2011
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: FENG, Hanying, CAO, Yu, YE, Jun, ZHANG, Youping
• Granted Patent: US 10,423,075 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G03F 7/70125 Use of illumination settings tailored to particular mask patterns details of setting means G03F7/70091
• CPC Class Codes: G03F 7/70258 Projection system adjustments, e.g. adjustments during exposure or alignment during assembly of projection system
• CPC Class Codes: G03F 7/70483 Information management; Active and passive control; Testing; Wafer monitoring, e.g. pattern monitoring
• 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 7/706 Aberration measurement
• CPC Class Codes: G03F 7/70683 Mark designs
• CPC Class Codes: G06F 17/10 Complex mathematical operations function generation by table look-up G06F1/03; evaluation of elementary functions by calculation G06F7/544

Abstract

The present invention relates to methods and systems for designing gauge patterns that are extremely sensitive to parameter variation, and thus robust against random and repetitive measurement errors in calibration of a lithographic process utilized to image a target design having a plurality of features. The method may include identifying most sensitive line width/pitch combination with optimal assist feature placement which leads to most sensitive CD (or other lithography response parameter) changes against lithography process parameter variations, such as wavefront aberration parameter variation. The method may also include designing gauges which have more than one test patterns, such that a combined response of the gauge can be tailored to generate a certain response to wavefront-related or other lithographic process parameters. The sensitivity against parameter variation leads to robust performance against random measurement error and/or any other measurement error.

Claims

1. A set of test patterns for a projection lithography system, wherein wavefront aberration terms mathematically represent characteristics of wavefront aberration in the projection lithography system, the set of test patterns comprising:

a test pattern that produces a desired response in a lithographic imaging parameter with respect to variation of a certain one of the wavefront aberration terms that mathematically represent characteristics of wavefront aberration in the projection lithography system,

wherein the set of test patterns is adapted to be included with a layout, and wherein the layout with the included set of test patterns is adapted to be imaged via a lithography process performed using the projection lithography system.

2. The set of test patterns according to claim 1, wherein the wavefront aberration terms comprise Zernike coefficients.

3. The set of test patterns according to claim 1, wherein the desired response is a linear response.

4. The set of test patterns according to claim 1, wherein the desired response is a linear response, and wherein the test pattern includes a pair of sub-patterns having offsetting non-linear responses.

5. The set of test patterns according to claim 1, wherein the test pattern includes a pair of sub-patterns that have a geometric relationship with each other that has been determined in accordance with the desired response.

6. The set of test patterns according to claim 5, wherein the desired response is a linear response, and wherein the geometric relationship is mirror symmetry.

7. The set of test patterns according to claim 5, wherein the desired response is a linear response, and wherein the geometric relationship is rotational.

8. The set of test patterns according to claim 1, wherein the certain one of the wavefront aberration terms is an odd-symmetric Zernike term.

9. The set of test patterns according to claim 1, wherein the certain one of the wavefront aberration terms is a spherical Zernike term.

10. The set of test patterns according to claim 1, wherein the desired response is a non-linear response.

11. The set of test patterns according to claim 1, wherein the desired response is a desired signal-to-noise ratio.

12. The set of test patterns according to claim 1, wherein the test pattern comprises substantially binary structures.

13. The set of test patterns according to claim 1, wherein the test pattern comprises phase-shifting structures.

14. The set of test patterns according to claim 1, wherein the test pattern has been derived from other patterns in the layout.

15. The set of test patterns according to claim 1, wherein the imaging of the layout via the lithography process causes formation of structures in a substrate corresponding to the layout.

16. A reticle comprising a set of test patterns for a projection lithography system, wherein wavefront aberration terms mathematically represent characteristics of wavefront aberration in the projection lithography system, the set of test patterns comprising:

a test pattern that produces a desired response in a lithographic imaging parameter with respect to variation of a certain one of the wavefront aberration terms that mathematically represent characteristics of wavefront aberration in the projection lithography system,

wherein the set of test patterns is adapted to be included with a layout, and wherein the layout with the included set of test patterns is adapted to be imaged via a lithography process performed using the projection lithography system.