# US 6,720,132 B2 · Bi-layer photoresist dry development and reactive ion etch method

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- Number: US 6,720,132 B2
- Document ID: US6720132B2
- Status: Granted
- Kind: B2
- Application number: 10/043,015
- Filed: 2002-01-08
- Published: 2003-07-10
- Granted: 2004-04-13
- Earliest claimed: 2002-01-08
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Inventors: Ming Huan Tsai; Hun-Jan Tao
- Web page: https://patentgrep.com/patent/US6720132B2

## CPC

- G03F 7/265: {Selective reaction with inorganic or organometallic reagents after image-wise exposure, e.g. silylation}
- G03F 7/094: {Multilayer resist systems, e.g. planarising layers}
- G03F 7/36: Imagewise removal not covered by groups G03F7/30 - G03F7/34, e.g. using gas streams, using plasma
- G03F 7/075: Silicon-containing compounds
- 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

A method for semiconductor device feature development using a bi-layer photoresist including providing a non-silicon containing photoresist layer over a substrate; providing a silicon containing photoresist layer over the non-silicon containing photoresist layer; exposing an exposure surface of the silicon containing photoresist layer to an activating light source said exposure surface defined by an overlying pattern according to a photolithographic process; developing the silicon containing photoresist layer according to a photolithographic process to reveal a portion the non-silicon containing photoresist layer; and, dry developing said non-silicon containing photoresist layer in a plasma reactor by igniting a plasma from an ambient mixture including at least hydrogen and carbon monoxide.

## Claims

### Claim 1

A method for semiconductor device feature development using a bi-layer photoresist to improve an etching resolution and reduce particulate contamination comprising the steps of:
providing a non-silicon containing organic resinous layer over a substrate to from a first resist layer;
providing a silicon containing photoresist layer over the first resist layer to form a second resist layer;
exposing an exposure surface of the second resist layer to an activating light source and wet developing the second resist layer to form a second resist layer pattern revealing first resist layer portions; and,
dry developing said first resist layer portions according to the second resist layer pattern to reveal the substrate in a plasma process comprising supplying hydrogen (H2) and carbon monoxide (CO) to form a dry development plasma.

### Claim 2 (depends on 1)

The method of claim 1, wherein the the first resist layer comprises a non-photoactive polymer.

### Claim 3 (depends on 1)

The method of claim 1, wherein the activating light source comprises a wavelength selected from the group consisting of about 157 nanometers and about 193 nanometers.

### Claim 4 (depends on 1)

The method of claim 1, wherein the first resist layer has a thickness greater than the second resist layer.

### Claim 5 (depends on 4)

The method of claim 4, wherein the first resist layer has a thickness of about 1000 Angstroms to about 5000 Angstroms and the second resist layer has a thickness of about 500 Angstroms to about 3000 Angstroms.

### Claim 6 (depends on 1)

The method of claim 1, further comprising the step of removing the second resist layer according to a first in-situ ashing process following the step of dry developing.

### Claim 7 (depends on 6)

The method of claim 6, wherein the first in-situ ashing process comprises an oxygen containing plasma said oxygen containing plasma further comprising at least one of nitrogen and fluorine ions said oxygen containing plasma to simultaneously clean plasma contact surfaces.

### Claim 8 (depends on 6)

The method of claim 6, further comprising the step of etching a semiconductor feature through at least a portion of the substrate according to a reactive ion etch process.

### Claim 9 (depends on 8)

The method of claim 8, wherein the semiconductor feature is selected from the group consisting of a via hole, a trench line, a contact hole, a shallow trench isolation feature, and a polysilicon gate feature.

### Claim 10 (depends on 8)

The method of claim 8, further comprising the step of removing the first resist layer according to a second in-situ ashing process following the step of etching.

### Claim 11 (depends on 10)

The method of claim 10, wherein the second in-situ ashing process further comprises an oxygen containing plasma further comprising at least one of nitrogen and fluorine, the oxygen containing plasma to simultaneously clean plasma contact surfaces.

### Claim 12 (depends on 10)

The method of claim 10, wherein the steps of dry developing, the first in-situ ashing process, the reactive ion etch process, and the second in-situ-ashing process, are carried out according to a continuous process.

### Claim 13 (depends on 1)

The method of claim 1, wherein the dry development plasma is formed of gases consisting essentially of hydrogen and carbon monoxide.

### Claim 14 (depends on 13)

The method of claim 13 wherein the dry development plasma is formed of gases consisting essentially of hydrogen, carbon monoxide, and argon.

### Claim 15 (depends on 1)

The method of claim 1, wherein the first resist layer is selected from the group consisting of an I-line photoresist, an acrylic polymer, and a polyvinyl alcohol polymer.

### Claim 16 (depends on 1)

The method of claim 1, wherein the second resist layer comprises a DUV photoresist wherein the silicon comprises silicon incorporated from one of a silylation process and from silicon monomers included in the photoresist.

### Claim 17

A method for etching a semiconductor device feature using a bi-layer photoresist to improve an etching resolution and reduce particulate contamination comprising the steps of:
providing a non-silicon containing organic resinous layer over a dielectric insulating layer to from a first resist layer;
providing a silicon containing photoresist layer over the first resist layer to form a second resist layer;
patterning the second resist layer according to a photolithographic exposure process comprising a wavelength of about 157 nm or about 193 nm;
wet developing the second resist layer to form a patterned second resist layer;
dry etching according to a dry etching chemistry formed by supplying gases consisting essentially of hydrogen (H2), carbon monoxide, and optionally, argon, the first resist layer portions to reveal the dielectric insulating layer to form an etching mask; and,
etching an opening in the dielectric insulating layer.

### Claim 18 (depends on 17)

The method of claim 17, wherein the second resist layer is removed in-situ according to an oxygen ashing process prior to the step of etching.

### Claim 19 (depends on 18)

The method of claim 18, wherein one of fluorine and nitrogen is added during the oxygen ashing process to simultaneously clean plasma contact surfaces including a plasma reactor chamber contact surface.

### Claim 20 (depends on 17)

The method of claim 17, wherein at least the first and second resist layers are removed in-situ according to an oxygen ashing process following the step of etching.

### Claim 21 (depends on 20)

The method of claim 20, wherein one of fluorine and nitrogen is added during the oxygen ashing process to simultaneously clean plasma reactor chamber surfaces.

### Claim 22 (depends on 17)

The method of claim 17, wherein the first resist layer is selected from the group consisting of an I-line photoresist, an acrylic polymer, and a polyvinyl alcohol polymer.

### Claim 23 (depends on 17)

The method of claim 17, wherein the second resist layer comprises a DUV photoresist wherein the silicon comprises silicon incorporated from one of a silylation process and from silicon monomers contained within the photoresist.