# US 12,183,589 B2 · Tin oxide mandrels in patterning

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- Number: US 12,183,589 B2
- Document ID: US12183589B2
- Status: Granted
- Kind: B2
- Application number: 17/302,847
- Filed: 2021-05-13
- Published: 2021-08-26
- Granted: 2024-12-31
- Earliest claimed: 2018-01-30
- Assignees: Lam Research Corporation
- Applicants: Lam Research Corporation
- Inventors: Jengyi Yu; Samantha S. H. Tan; Seongjun Heo; Boris Volosskiy; Sivananda Krishnan Kanakasabapathy; Richard Wise; Yang Pan; Hui-Jung Wu
- Web page: https://patentgrep.com/patent/US12183589B2

## CPC

- H10P 50/267: {using plasmas}
- C04B 41/5346: {Dry etching}
- C04B 41/91: involving the removal of part of the materials of the treated articles, e.g. etching
- C23C 16/0227: {by cleaning or etching}
- C23C 16/045: {Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates}
- C23C 16/34: Nitrides {(C23C16/303 takes precedence)}
- C23C 16/401: {containing silicon}
- C23C 16/45538: {Plasma being used continuously during the ALD cycle}
- C23C 16/52: Controlling or regulating the coating process {(C23C16/45557, C23C16/279 take precedence)}
- H10P 50/20: Dry etching; Plasma etching; Reactive-ion etching
- H10P 50/283: {by chemical means}
- H10P 50/285: {of materials not containing Si, e.g. PZT or Al2O3}
- H10P 50/287: {by chemical means}
- H10P 50/69: {using masks for semiconductor materials}
- H10P 50/71: {using masks for conductive or resistive materials}
- H10P 52/00: Grinding, lapping or polishing of wafers, substrates or parts of devices
- H10P 72/0454: {surrounding a central transfer chamber}
- H10P 72/0606: {Position monitoring, e.g. misposition detection or presence detection}
- H10P 72/0612: {Production flow monitoring, e.g. for increasing throughput}
- H10P 76/4085: {characterised by the processes involved to create the masks}
- H10P 95/70: Chemical treatments
- H10P 14/3412: {including tin}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)

## Abstract

Tin oxide films are used as mandrels in semiconductor device manufacturing. In one implementation the process starts by patterning a tin oxide layer using at least one of a hydrogen-based etch chemistry and a chlorine-based etch chemistry, and using patterned photoresist as a mask, thereby providing a substrate having a plurality of protruding tin oxide features (mandrels). Next, a conformal layer of spacer material is formed both on the horizontal surfaces and on the sidewalls of the mandrels. The spacer material is then removed from the horizontal surfaces exposing the tin oxide material of the mandrels, without fully removing the spacer material residing at the sidewalls of the mandrels. Next, mandrels are selectively removed (e.g., using hydrogen-based etch chemistry), while leaving the spacer material that resided at the sidewalls of the mandrels. The resulting spacers can be used for patterning underlying layers on the substrate.

## Claims

### Claim 1

A method of processing a semiconductor substrate, the method comprising:
(a) providing a semiconductor substrate having a patterned photoresist layer overlying a tin oxide layer;
(b) etching a plurality of openings in the tin oxide layer using the patterned photoresist layer as a mask, wherein etching the plurality of openings comprises etching the tin oxide layer using a hydrogen-based etch chemistry to form a tin hydride;
(c) at least partially removing the photoresist layer using an oxygen-based etch chemistry and forming a plurality of tin oxide mandrels;
(d) depositing a layer of spacer material over the tin oxide mandrels such that the spacer material coats sidewalls of the tin oxide mandrels and horizontal portions of the tin oxide mandrels;
(e) removing the spacer material from the horizontal portions of the tin oxide mandrels, and
(f) removing the tin oxide mandrels to form a plurality of spacers on the semiconductor substrate.

### Claim 2 (depends on 1)

The method of claim 1, wherein (b) comprises etching the tin oxide layer using the hydrogen-based etch chemistry, and wherein the etching comprises contacting the semiconductor substrate with H2 activated in a plasma and Cl2 activated in a plasma.

### Claim 3 (depends on 2)

The method of claim 2, wherein a process gas used for etching the tin oxide layer further comprises an inert gas.

### Claim 4 (depends on 2)

The method of claim 2, wherein a process gas used for etching the tin oxide layer further comprises an inert gas selected from the group consisting of argon, N2, and combinations thereof.

### Claim 5 (depends on 1)

The method of claim 1, wherein (b) comprises etching the tin oxide layer using the hydrogen-based etch chemistry, wherein the etching comprises contacting the semiconductor substrate with a plasma formed in a process gas comprising H2 and Cl2, wherein H2 concentration in the process gas is at least 50%.

### Claim 6 (depends on 1)

The method of claim 1, wherein (b) comprises etching the tin oxide layer using the hydrogen-based etch chemistry, wherein the etching comprises contacting the semiconductor substrate with a plasma formed in a process gas comprising H2 and Cl2, wherein H2 concentration in the process gas is at least 80%.

### Claim 7 (depends on 1)

The method of claim 1, wherein etching of the tin oxide layer in (b) is conducted using an etch chemistry that etches tin oxide at a higher etch rate than photoresist.

### Claim 8 (depends on 1)

The method of claim 1, wherein (b) comprises etching the tin oxide layer using the hydrogen-based etch chemistry, wherein the etching comprises forming a plasma in a process gas comprising a hydrogen-containing gas selected from the group consisting of H2, HBr, NH3, H2O, a hydrocarbon, and combinations thereof.

### Claim 9 (depends on 1)

The method of claim 1, wherein the semiconductor substrate provided in (a) comprises one or more intermediate layers between the tin oxide layer and the patterned photoresist layer, and wherein etching a plurality of openings in the tin oxide layer using the patterned photoresist layer as a mask comprises transferring a pattern of the patterned photoresist layer to the one or more intermediate layers.

### Claim 10 (depends on 1)

The method of claim 1, wherein the photoresist is completely removed in (c) after the openings in the tin oxide layer are formed.

### Claim 11 (depends on 1)

The method of claim 1, wherein the semiconductor substrate provided in (a) comprises one or more intermediate layers between the tin oxide layer and the patterned photoresist layer, wherein etching a plurality of openings in the tin oxide layer using the patterned photoresist layer as a mask comprises transferring a pattern of the patterned photoresist layer to the one or more intermediate layers, and wherein the photoresist is completely removed in (c) before the openings in the tin oxide layer are formed.

### Claim 12 (depends on 1)

The method of claim 1, further comprising:
(g) after (f) using the plurality of spacers as a mask to etch one or more underlying layers.

### Claim 13 (depends on 1)

The method of claim 1, wherein removing the tin oxide mandrels in (e) comprises etching the tin oxide mandrels using a hydrogen-based etch chemistry.

### Claim 14 (depends on 1)

The method of claim 1, wherein removing the tin oxide mandrels in (f) comprises etching the tin oxide mandrels using a hydrogen-based etch chemistry by exposing the semiconductor substrate to a process gas comprising a gas selected from the group consisting of H2, HBr, and NH3, and combinations thereof.

### Claim 15 (depends on 1)

The method of claim 1, wherein removing the spacer material from the horizontal portions of the tin oxide mandrels comprises using an etch chemistry that etches the spacer material at a faster rate than the tin oxide layer.

### Claim 16 (depends on 1)

The method of claim 1, wherein the spacer material is selected from the group consisting of a silicon-containing material, a carbon-containing material, and a metal oxide.

### Claim 17 (depends on 1)

The method of claim 1, wherein the spacer material is a silicon-containing material, and wherein (c) comprises removing the spacer material from horizontal surfaces using a fluorocarbon etch chemistry selectively to tin oxide.

### Claim 18 (depends on 1)

The method of claim 1, wherein (c) comprises removing the photoresist using the oxygen-based etch chemistry to expose the tin oxide layer.

### Claim 19 (depends on 1)

The method of claim 1, further comprising:
(g) after (f), using the spacers to form a plurality of openings in an etch stop layer underlying the spacers, and in a target layer, underlying the etch stop layer.

### Claim 20

A method of processing a semiconductor substrate, the method comprising:
(a) providing a semiconductor substrate having a patterned photoresist layer overlying a tin oxide layer;
(b) etching a plurality of openings in the tin oxide layer using the patterned photoresist layer as a mask, wherein etching the plurality of openings comprises etching the tin oxide layer using (i) a hydrogen-based etch chemistry to form a tin hydride and (ii) a chlorine-based etch chemistry;
(c) at least partially removing the photoresist layer using an oxygen-based etch chemistry and forming a plurality of tin oxide mandrels;
(d) depositing a layer of spacer material over the tin oxide mandrels such that the spacer material coats sidewalls of the tin oxide mandrels and horizontal portions of the tin oxide mandrels;
(e) removing the spacer material from the horizontal portions of the tin oxide mandrels; and
(f) removing the tin oxide mandrels to form a plurality of spacers on the semiconductor substrate.