# US 10,312,146 B2 · Method for fabricating semiconductor device

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- Number: US 10,312,146 B2
- Document ID: US10312146B2
- Status: Granted
- Kind: B2
- Application number: 15/647,031
- Filed: 2017-07-11
- Published: 2019-01-17
- Granted: 2019-06-04
- Earliest claimed: 2017-07-11
- Assignees: United Microelectronics Corp.
- Applicants: United Microelectronics Corp.
- Inventors: Ching-Ling Lin; Wen-An Liang; Chen-Ming Huang
- Web page: https://patentgrep.com/patent/US10312146B2

## CPC

- H10D 84/038: {using silicon technology, e.g. SiGe}
- H10D 30/0243: {using dummy structures having essentially the same shapes as the semiconductor bodies, e.g. to provide stability}
- H10D 30/6219: {characterised by the source or drain electrodes}
- H10D 84/0151: {Manufacturing their isolation regions}
- H10D 84/0158: {the components including FinFETs}
- H10D 84/0193: {the components including FinFETs}
- H10D 84/834: {comprising FinFETs}
- H10D 86/011: {comprising FinFETs}
- H10P 14/65: {characterised by treatments performed before or after the formation of the materials}
- 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 76/405: {characterised by their composition, e.g. multilayer masks}
- H10P 76/4085: {characterised by the processes involved to create the masks}
- H10P 95/90: Thermal treatments, e.g. annealing or sintering
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A method for fabricating a semiconductor structure includes forming a plurality of mandrels over a substrate, wherein the substrate comprises a semiconductor substrate as a base. Then, a first dielectric layer is formed to cover on a predetermined mandrel of the mandrels. A second dielectric layer is formed over the substrate to cover the mandrels. The mandrels are removed, wherein a remaining portion of the first dielectric layer and the second dielectric layer at a sidewall of the mandrels remains on the substrate. An anisotropic etching process is performed over the substrate until a top portion of the semiconductor substrate is etched to form a plurality of fins corresponding to the remaining portion of the first dielectric layer and the second dielectric layer.

## Claims

### Claim 1

A method for fabricating a semiconductor structure, comprising:
forming a plurality of mandrels over a substrate, wherein the substrate comprises a semiconductor substrate as a base;
forming a first dielectric layer to cover on a predetermined mandrel of the mandrels;
forming a second dielectric layer over the substrate to cover the mandrels;
removing the mandrels, wherein a remaining portion of the first dielectric layer and the second dielectric layer at a sidewall of the mandrels remains on the substrate;
performing an anisotropic etching process over the substrate until a top portion of the semiconductor substrate is etched to form a plurality of fins corresponding to the remaining portion of the first dielectric layer and the second dielectric layer, wherein the fins comprises first fins corresponding to the first dielectric layer with the second dielectric layer and second fins corresponding to the second dielectric layer without the first dielectric layer, and the first fins are thicker than the second fins;
removing a dummy fin of the fins, wherein at least one fin of the first fins subjecting to the first dielectric layer at an area adapting for a separately isolated device remains;
depositing oxide over the substrate to form an oxide layer covering the fins as remained; and
performing an annealing process over the substrate, wherein the at least one fin of the first fins has more surface oxidation thickness due to the annealing process than the second fins.

### Claim 2 (depends on 1)

The method of claim 1, further comprising removing a top portion of the oxide layer to expose the fins.

### Claim 3 (depends on 1)

The method of claim 1, the step of forming the first dielectric layer comprises:
forming a global dielectric layer over the substrate;
forming a mask layer over the substrate to cover a predetermined sidewall of the predetermined mandrel;
removing the global dielectric layer using the mask layer as an etching mask; and
removing the mask layer.

### Claim 4 (depends on 3)

The method of claim 3, wherein the mask layer covers both the sidewall of the predetermined mandrels or just one sidewall of the predetermined mandrels.

### Claim 5 (depends on 1)

The method of claim 1, wherein the substrate further comprises a stack dielectric layer on the semiconductor substrate.

### Claim 6 (depends on 1)

The method of claim 1, wherein a thickness of the first dielectric layer is less than a thickness of the second dielectric layer.

### Claim 7 (depends on 1)

The method of claim 1, wherein a thickness of the first dielectric layer is in a range of 1-5 nm.

### Claim 8 (depends on 7)

The method of claim 7, wherein a thickness of the first dielectric layer is in a range of 1-2 nm.

### Claim 9 (depends on 7)

The method of claim 7, wherein a width of the fins is in a range of 15-20 nm.

### Claim 10 (depends on 1)

The method of claim 1, wherein a thickness of the first dielectric layer is used to compensate a semiconductor consumption on a sidewall surface of the fin corresponding to the predetermined mandrel.

### Claim 11 (depends on 1)

The method of claim 1, wherein a ratio of a thickness of the first dielectric layer to a width of the fins is in a range of 10 to 20.

### Claim 12 (depends on 1)

The method of claim 1, wherein the step of removing the mandrels comprises:
performing an etching back process on the first dielectric layer and the second dielectric layer to form a dielectric spacer on a sidewall of the mandrels, wherein the dielectric spacer of the predetermined mandrels comprises the first dielectric layer; and
removing the mandrels.

### Claim 13 (depends on 12)

The method of claim 12, wherein a material of the mandrel is a material, so to be distinct over dielectric material of the first dielectric layer and the second dielectric layer in etching.

### Claim 14 (depends on 13)

The method of claim 13, wherein a material of the mandrels is polysilicon.

### Claim 15 (depends on 13)

The method of claim 13, wherein the first dielectric layer and the second dielectric layer are silicon nitride.

### Claim 16 (depends on 1)

The method of claim 1, wherein the dummy fin as removed is abut to the at least one fin of the fins.

### Claim 17 (depends on 16)

The method of claim 16, wherein the dummy fin also comprises a fin having the first dielectric layer but not to be used.

### Claim 18 (depends on 1)

The method of claim 1, wherein the predetermined mandrel is located at an area adapting for the separately isolated device.