# US 10,312,103 B2 · Alternating hardmasks for tight-pitch line formation

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- Number: US 10,312,103 B2
- Document ID: US10312103B2
- Status: Granted
- Kind: B2
- Application number: 15/445,112
- Filed: 2017-02-28
- Published: 2018-08-30
- Granted: 2019-06-04
- Earliest claimed: 2017-02-28
- Assignees: International Business Machines Corporation
- Applicants: International Business Machines Corporation
- Inventors: Sean D. Burns; Nelson M. Felix; Chi-Chun Liu; Yann A. M. Mignot; Stuart A. Sieg
- Web page: https://patentgrep.com/patent/US10312103B2

## CPC

- H10P 50/696: {Process specially adapted to improve the resolution of the mask}
- H10D 30/024: {of fin field-effect transistors [FinFET]}
- H10D 84/0158: {the components including FinFETs}
- H10D 84/038: {using silicon technology, e.g. SiGe}
- H10P 50/242: {of Group IV materials}
- H10P 50/692: {characterised by their composition, e.g. multilayer masks or materials}
- H10P 50/694: {characterised by their behaviour during the process, e.g. soluble masks or redeposited masks}
- H10P 50/695: {characterised by the process involved to create the mask, e.g. lift-off masks or sidewalls or to modify the mask}
- H10P 76/4085: {characterised by the processes involved to create the masks}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

A method for forming fins includes forming a three-color hardmask fin pattern on a fin base layer. The three-color hardmask fin pattern has hardmask fins of three mutually selectively etchable compositions. A region on the three-color hardmask fin pattern is masked, leaving one or more fins of a first color exposed. All exposed fins of the first color are etched away with a selective etch that does not remove fins of a second color or a third color. The mask and all fins of a second color are etched away. Fins are etched into the fin base layer by anisotropically etching around remaining fins of the first color and fins of the third color.

## Claims

### Claim 1

A wafer, comprising:
a plurality of fins of three distinct materials, comprising fins of a first material (A), fins of a second material (B), and fins of a third material (C), wherein the fins are arranged in contact with one another in a pattern of ABCBABCBA and are disposed directly on a layer of a fourth distinct material; and
fin caps disposed on the fins of the first material, with a top surface that has a height higher than a top surface of the fins of the second material and a bottom surface that has a height lower than the top surface of the fins of the second material.

### Claim 2 (depends on 1)

The wafer of claim 1, wherein the first material comprises amorphous silicon, the second material comprises carbon, and the third material comprises silicon dioxide.

### Claim 3 (depends on 1)

The wafer of claim 1, wherein the fins of the second material have a height that is below the height of the fins of the third material.

### Claim 4 (depends on 1)

The wafer of claim 1, wherein the fourth material comprises silicon nitride.

### Claim 5 (depends on 1)

The wafer of claim 1, wherein the fin caps have a thickness of about 5 nm.

### Claim 6 (depends on 1)

The wafer of claim 1, wherein the fin caps comprise the fourth material.

### Claim 7 (depends on 1)

The wafer of claim 1, wherein the fin caps comprise a fifth distinct material.

### Claim 8 (depends on 1)

The wafer of claim 1, further comprising a semiconductor layer under the layer of the fourth material.

### Claim 9

A wafer, comprising:
a plurality of fins of three distinct materials, comprising fins of a first material (A), fins of a second material (B), and fins of a third material (C), wherein the fins are arranged in contact with one another in a pattern of ABCBABCBA and are disposed directly on a layer of a fourth distinct material;
fin caps disposed on the fins of the first material, formed from a material selected from the group consisting of the fourth material and a fifth distinct material.

### Claim 10 (depends on 9)

The wafer of claim 9, wherein the first material comprises amorphous silicon, the second material comprises carbon, and the third material comprises silicon dioxide.

### Claim 11 (depends on 9)

The wafer of claim 9, wherein the fins of the second material have a height that is below the height of the fins of the first material and the fins of the third material.

### Claim 12 (depends on 9)

The wafer of claim 9, wherein the fourth material comprises silicon nitride.

### Claim 13 (depends on 9)

The wafer of claim 9, wherein the fin caps have a thickness of about 5 nm.

### Claim 14 (depends on 9)

The wafer of claim 9, further comprising a semiconductor layer under the layer of the fourth material.

### Claim 15 (depends on 9)

The wafer of claim 9, wherein a top surface of the fin caps has a height higher than a top surface of the fins of the second material and wherein a bottom surface of the fin caps has a height lower than the top surface of the fins of the second material.