# US 12,117,733 B2 · Method for measuring critical dimension

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- Number: US 12,117,733 B2
- Document ID: US12117733B2
- Status: Granted
- Kind: B2
- Application number: 17/584,889
- Filed: 2022-01-26
- Published: 2023-07-27
- Granted: 2024-10-15
- Earliest claimed: 2022-01-26
- Assignees: Nanya Technology Corporation
- Applicants: Nanya Technology Corporation
- Inventors: Chia-Chung Lin
- Web page: https://patentgrep.com/patent/US12117733B2

## CPC

- G03F 7/70625: {Dimensions, e.g. line width, critical dimension [CD], profile, sidewall angle or edge roughness}
- G03F 7/095: having more than one photosensitive layer (G03F7/075 takes precedence)
- G03F 7/168: {Finishing the coated layer, e.g. drying, baking, soaking}
- G03F 7/38: Treatment before imagewise removal, e.g. prebaking {(G03F7/265 takes precedence)}
- G03F 7/40: Treatment after imagewise removal, e.g. baking
- G03F 7/70608: {Monitoring the unpatterned workpiece, e.g. measuring thickness, reflectivity or effects of immersion liquid on resist}
- G03F 7/70655: {Non-optical, e.g. atomic force microscope [AFM] or critical dimension scanning electron microscope [CD-SEM]}
- G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G)

## Abstract

The present application discloses a method for measuring critical dimension. The method for measuring critical dimension includes providing a substrate; forming a resist layer over the substrate; monitoring a volatile byproduct evolved from the resist layer to obtain a first amount of the volatile byproduct; exposing the resist layer to a radiation source; heating the resist layer; monitoring the volatile byproduct evolved from the resist layer to obtain a second amount of the volatile byproduct; and deducting the critical dimension according to a difference between the first amount of the volatile byproduct and the second amount of the volatile byproduct.

## Claims

### Claim 1

A method for measuring critical dimension, comprising:
providing a substrate;
forming a resist layer over the substrate, wherein the resist layer comprises a solvent, a nonactivated polymer resin, a photoacid generator, and a photosensitizer generator;
exposing the resist layer to a radiation source in a first wavelength;
exposing the resist layer to a radiation source in a second wavelength different from the first wavelength;
heating the resist layer;
continuously monitoring a volatile byproduct evolved from the resist layer from a first time point after forming the resist layer over the substrate to a second time point after heating the resist layer, to obtain a concentration curve of the volatile byproduct; and
deducting the critical dimension according to an integration of the concentration curve between the first time point and the second time point;
wherein the photosensitizer generator is sensitive to the second wavelength and the photoacid generator is not sensitive to the second wavelength.

### Claim 2 (depends on 1)

The method for measuring critical dimension of claim 1, wherein the first wavelength is less than 300 nm, and the second wavelength is greater than 300 nm.

### Claim 3 (depends on 2)

The method for measuring critical dimension of claim 2, wherein the solvent comprises propylene glycol monomethyl ether acetate, water, or a volatile amine-containing compound.

### Claim 4 (depends on 1)

The method for measuring critical dimension of claim 1, wherein the volatile byproduct comprises carbon dioxide, propylene glycol monomethyl ether acetate, water, alcohols, volatile amine-containing compounds, hydrocarbons, aldehydes, vinyl ether, and/or sulfides.

### Claim 5 (depends on 4)

The method for measuring critical dimension of claim 4, further comprising performing a soft bake process between forming the resist layer over the substrate and exposing the resist layer to the radiation source in the first wavelength.

### Claim 6 (depends on 5)

The method for measuring critical dimension of claim 5, wherein performing the soft bake process comprising heating the resist layer to about a glass-transition temperature of the nonactivated polymer resin.

### Claim 7 (depends on 6)

The method for measuring critical dimension of claim 6, wherein continuously monitoring the volatile byproduct evolved from the resist layer is achieved by a residual gas analyzer.

### Claim 8 (depends on 7)

The method for measuring critical dimension of claim 7, wherein the residual gas analyzer is integrated within a post-exposure bake module of a photolithography track system.

### Claim 9 (depends on 8)

The method for measuring critical dimension of claim 8, further comprising correlating the critical dimension deducted from integration of the concentration curve between the first time point and the second time point with physical failure analysis results.

### Claim 10 (depends on 9)

The method for measuring critical dimension of claim 9, further comprising performing a development process after heating the resist layer.