Method and apparatus for source mask optimization configured to increase scanner throughput for a patterning process

Patent metadata

Field	Value
Publication number	US-2020249578-A1
Application number	US-202016777941-A
Country	US
Kind code	A1
Filing date	Jan 31, 2020
Priority date	Feb 1, 2019
Publication date	Aug 6, 2020
Grant date	—

Abstract

A method for optimization to increase lithographic apparatus throughput for a patterning process is described. The method includes providing a baseline dose for an EUV illumination and an initial pupil configuration, associated with a lithographic apparatus. The baseline dose and the initial pupil configuration are configured for use with a dose anchor mask pattern and a corresponding dose anchor target pattern for setting an illumination dose for corresponding device patterns of interest. The method includes biasing the dose anchor mask pattern relative to the dose anchor target pattern; determining an acceptable lower dose for the biased dose anchor mask pattern and the initial pupil configuration; unbiasing the dose anchor mask pattern relative to the dose anchor target pattern; and determining a changed pupil configuration and a mask bias for the device patterns of interest based on the acceptable lower dose and the unbiased dose anchor mask pattern.

First claim

What is claimed is:

1 . A method for configuring an extreme ultra violet (EUV) lithographic apparatus, the method comprising:
providing a baseline dose for an EUV illumination and an initial pupil configuration, wherein the baseline dose and the initial pupil configuration are configured for use with a dose anchor mask pattern and a corresponding dose anchor target pattern for setting an illumination dose for corresponding device patterns of interest; biasing the dose anchor mask pattern relative to the dose anchor target pattern; determining an acceptable lower dose for the biased dose anchor mask pattern and the initial pupil configuration; unbiasing the dose anchor mask pattern relative to the dose anchor target pattern; and determining a changed pupil configuration and a mask bias for the device patterns of interest based on the acceptable lower dose and the unbiased dose anchor mask pattern.

2 . The method of claim 1 , wherein biasing the dose anchor mask pattern relative to the dose anchor target pattern comprises dimensionally shifting the dose anchor mask pattern relative to the dose anchor target pattern in one or more dimensions.

3 . The method of claim 1 , wherein biasing the dose anchor mask pattern relative to the dose anchor target pattern comprises dimensionally shifting one or more edges of one or more features of the dose anchor mask pattern.

4 . The method of claim 3 , wherein the one or more features of the dose anchor mask pattern are one dimensional or two dimensional.

5 . The method of claim 1 , wherein biasing the dose anchor mask pattern relative to the dose anchor target pattern is symmetrical or asymmetrical.

6 . The method of claim 1 , wherein biasing the dose anchor mask pattern relative to the dose anchor target pattern comprises enlarging one or more device patterns and a corresponding mask bias of the device patterns of interest.

7 . The method of claim 1 , wherein determining the acceptable lower dose for the biased dose anchor mask pattern and the initial pupil configuration comprises a dose and focus optimization.

8 . The method of claim 1 , wherein providing the baseline dose for the EUV illumination and the initial pupil configuration comprises:
optimizing a freeform or parametric pupil and the dose anchor mask pattern; optimizing a continuous transmission mask (CTM) and extracting main and assist features; optimizing pupil and polygon masks at different dose levels; mapping a discrete pupil; performing a dose and focus optimization; determining the baseline dose and the initial pupil configuration based on the dose and focus optimization; and providing the baseline dose for the EUV illumination and the initial pupil configuration.

9 . The method of claim 8 , further comprising, after determining the changed pupil configuration based on the acceptable lower dose, or a higher dose, and the unbiased dose anchor mask pattern:
normalizing an intensity of the EUV illumination to optimize a free form illumination mask co-optimization with a fixed dose and a fixed illumination intensity set at the acceptable lower dose, or the higher dose, with a pupil telecentricity penalty; mapping a continuous pupil produced by the changed pupil configuration to a discrete pupil; performing a dose and focus optimization using a dose anchor feature and a focus anchor feature, simultaneously or sequentially; performing a mask only optimization of the device patterns of interest with the discrete pupil at the acceptable lower dose; optimizing the acceptable lower dose based on a difference between Abbe and Hopkins model outputs; optimizing the mask bias for the device patterns of interest through a slit using the optimized acceptable lower dose; and determining lithographic apparatus throughput based on the optimized acceptable lower dose and a relative lithographic apparatus throughput model.

10 . The method of claim 1 , further comprising, after determining the changed pupil configuration and the mask bias for the device patterns of interest:
performing a discrete mirror state optimization at the acceptable lower dose, or a higher dose; optimizing the acceptable lower dose based on a difference between Abbe and Hopkins model outputs; optimizing the mask bias for the device patterns of interest through a slit using the optimized acceptable lower dose, or the higher dose; and determining lithographic apparatus throughput based on the optimized acceptable lower dose and a relative lithographic apparatus throughput model.

11 . The method of claim 1 , wherein the providing the baseline dose, the biasing the dose anchor mask pattern, the determining the acceptable lower dose, the unbiasing the dose anchor mask pattern, and the determining the changed pupil configuration and the mask bias are performed for an aerial image model.

12 . The method of claim 1 , wherein the providing the baseline dose, the biasing the dose anchor mask pattern, the determining the acceptable lower dose, the unbiasing the dose anchor mask pattern, and the determining the changed pupil configuration and the mask bias are performed for a resist image model.

13 . The method of claim 1 , wherein the providing the baseline dose, the biasing the dose anchor mask pattern, the determining the acceptable lower dose, the unbiasing the dose anchor mask pattern, and the determining the changed pupil configuration and the mask bias are performed at any numerical aperture and/or wavelength.

14 . The method of claim 1 , wherein the providing the baseline dose, the biasing the dose anchor mask pattern, the determining the acceptable lower dose, the unbiasing the dose anchor mask pattern, and the determining the changed pupil configuration and the mask bias are performed as part of a memory chip, logic chip, and/or microprocessor chip fabrication process.

15 . The method of claim 1 , wherein the providing the baseline dose, the biasing the dose anchor mask pattern, the determining the acceptable lower dose, the unbiasing the dose anchor mask pattern, and the determining the changed pupil configuration and the mask bias are performed as part of an illumination mask optimization (SMO) process.

16 . The method of claim 1 , wherein the providing the baseline dose, the biasing the dose anchor mask pattern, the determining the acceptable lower dose, the unbiasing the dose anchor mask pattern, and the determining the changed pupil configuration and the mask bias are performed such that a performance parameter is maintained at an acceptable level.

17 . The method of claim 16 , wherein the performance parameter is one or more selected from: normalized image log slope (NILS), depth of focus (DOF), line edge roughness (LER), local CD uniformity (LCDU), or stochastic edge placement error (SEPE).

18 . The method of claim 1 , further comprising determining a lithographic apparatus throughput for the EUV lithographic apparatus.

19 . The method of claim 18 , wherein the lithographic apparatus throughput is determined based on a relative throughput model comprising one or more machine specific constants, a transmission penalty, an illumination power, the acceptable lower dose or a higher dose, the baseline dose, and a relative change between the baseline dose and the acceptable lower dose or the higher dose.

20 . The method of claim 1 , wherein the baseline dose and the initial pupil configuration are configured for use with the dose anchor mask pattern and the corresponding dose anchor target pattern for

Assignees

• Asml Netherlands Bv

Inventors

• Hsu Duan-Fu Stephen
• Liu Jingjing

Classifications

• G03F7/70558 Primary

  Dose control, i.e. achievement of a desired dose · CPC title

• G03F7/70625

  Dimensions, e.g. line width, critical dimension [CD], profile, sidewall angle or edge roughness · CPC title

• G03F7/70441

  Optical proximity correction [OPC] · CPC title

• G03F7/70091 Primary

  Illumination settings, i.e. intensity distribution in the pupil plane or angular distribution in the field plane; On-axis or off-axis settings, e.g. annular, dipole or quadrupole settings; Partial coherence control, i.e. sigma or numerical aperture [NA] · CPC title

• G03F7/705 Primary

  Modelling or simulating from physical phenomena up to complete wafer processes or whole workflow in wafer productions · CPC title