Focus centering method for digital lithography

Patent metadata

Field	Value
Publication number	US-2018024448-A1
Application number	US-201715649249-A
Country	US
Kind code	A1
Filing date	Jul 13, 2017
Priority date	Jul 19, 2016
Publication date	Jan 25, 2018
Grant date	—

Abstract

Embodiments disclosed herein generally relate to adjusting a focus setting for a digital lithography system. The method includes scanning a surface of a photoresist. The photoresist is formed on a substrate. A focus setting for the digital lithography system is determined. A plurality of exposure location on the photoresist are located. A sidewall width of the exposure is measured for a plurality of focus settings. The focus setting is adjusted in response to determining a minimum sidewall width.

First claim

What is claimed is:

1 . A method of adjusting focus setting for a digital lithography system, comprising:
scanning a surface of a photoresist formed on a substrate; determining a focus setting for the digital lithography system, comprising:
locating a plurality of exposures on the photoresist; and
measuring a sidewall width of each exposure for a plurality of focus settings; and
adjusting the focus setting in response to determining a minimum sidewall width.

2 . The method of claim 1 , wherein the focus settings range from −100 μm to 100 μm.

3 . The method of claim 2 , wherein the focus settings range from −30 μm to 30 μm.

4 . The method of claim 1 , wherein measuring a sidewall width of the exposure for a plurality of focus settings, comprises:
measuring a sidewall width at a plurality of points along the sidewall of the exposure.

5 . The method of claim 1 , wherein determining a focus setting for the digital lithography system, further comprises:
determining a focus setting for the digital lithography system for each image projection system in the digital lithography system.

6 . The method of claim 1 , wherein the surface of the photoresist is scanned using a three-dimensional optical profiler.

7 . The method of claim 6 , wherein the three-dimensional optical profiler uses light emitting diodes as a light source.

8 . A computer system for adjusting a focus setting for a digital lithography system, comprising:
a processor; and a memory storing instructions that, when executed by the processor, cause the computer system to:
scanning a surface of a photoresist formed on a substrate;
determining a focus setting for the digital lithography system, comprising:
locating a plurality of exposures on the photoresist; and
measuring a sidewall width of each exposure for a plurality of focus settings; and

adjusting the focus setting in response to determining a minimum sidewall width.

9 . The computer system of claim 8 , wherein the focus settings range from −100 μm to 100 μm.

10 . The computer system of claim 9 , wherein the focus settings range from −30 μm to 30 μm.

11 . The computer system of claim 8 , wherein measuring a sidewall width of the exposure for a plurality of focus settings, comprises:
measuring a sidewall width at a plurality of points along the sidewall of the exposure.

12 . The computer system of claim 8 , wherein determining a focus setting for the digital lithography system, further comprises:
determining a focus setting for the digital lithography system for each image projection system in the digital lithography system.

13 . The computer system of claim 8 , wherein the surface of the photoresist is scanned using a three-dimensional optical profiler.

14 . The computer system of claim 8 , wherein the three-dimensional optical profiler uses light emitting diodes as a light source.

15 . A non-transitory computer-readable medium storing instructions that, when executed by a processor, cause a computer system to adjust a focus setting for a digital lithography system, by performing the steps of:
scan a surface of a photoresist formed on a substrate; determine a focus setting for the digital lithography system, comprising:
locate a plurality of exposures on the photoresist; and
measure a sidewall width of each exposure for a plurality of focus settings; and
adjust the focus setting in response to determining a minimum sidewall width.

16 . The non-transitory computer-readable medium of claim 15 , wherein the focus settings range from −100 μm to 100 μm.

17 . The non-transitory computer-readable medium of claim 16 , wherein the focus settings range from −30 μm to 30 μm.

18 . The non-transitory computer-readable medium of claim 15 , wherein measuring a sidewall width of the exposure for a plurality of focus settings, comprises:
measuring a sidewall width at a plurality of points along the sidewall of the exposure.

19 . The non-transitory computer-readable medium of claim 15 , wherein determining a focus setting for the digital lithography system, further comprises:
determining a focus setting for the digital lithography system for each image projection system in the digital lithography system.

20 . The non-transitory computer-readable medium of claim 15 , wherein the surface of the photoresist is scanned using a three-dimensional optical profiler.

Assignees

• Applied Materials Inc

Inventors

• Tung Yeishin
• Van Den Broeke Douglas Joseph
• Manens Antoine P
• Chen Jang Fung

Classifications

• G03F7/70641

  Focus · CPC title

• G03F7/70275 Primary

  Multiple projection paths, e.g. array of projection systems, microlens projection systems or tandem projection systems · CPC title

• G03F7/70625

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

• G03F9/7026 Primary

  Focusing · CPC title

• G03F7/70291

  Addressable masks, e.g. spatial light modulators [SLMs], digital micro-mirror devices [DMDs] or liquid crystal display [LCD] patterning devices · CPC title