# US 11,443,941 B2 · Silicon on insulator structure and method of making the same

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- Number: US 11,443,941 B2
- Document ID: US11443941B2
- Status: Granted
- Kind: B2
- Application number: 17/161,318
- Filed: 2021-01-28
- Published: 2022-06-09
- Granted: 2022-09-13
- Earliest claimed: 2020-12-08
- Assignees: Zing Semiconductor Corporation; Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences
- Applicants: Zing Semiconductor Corporation; Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences
- Inventors: Xing Wei; Nan Gao; Zhongying Xue
- Web page: https://patentgrep.com/patent/US11443941B2

## CPC

- H10P 14/2922: {being non-crystalline insulating materials, e.g. glass or polymers}
- H10P 90/1916: {with separation or delamination along an ion implanted layer, e.g. Smart-cut}
- H10P 14/38: {characterised by treatments done after the formation of the materials}
- H10P 50/00: Etching of wafers, substrates or parts of devices
- H10P 50/242: {of Group IV materials}
- H10P 50/642: {Chemical etching}
- H10P 90/1906: {Preparing SOI wafers}
- H10W 10/181: {Semiconductor-on-insulator [SOI] isolation regions, e.g. buried oxide regions of SOI wafers}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

A method of making a silicon on insulator structure comprises: providing a bonded structure, the bonded structure comprises the first substrate, the second substrate and the insulating buried layer, the insulating buried layer is positioned between the first substrate and the second substrate; peeling off a layer of removing region of the first substrate from the bonded structure to obtain a first film; at a first temperature, performing a first etching to etch the first film to remove a first thickness of the first film; at a second temperature, performing a second etching to etch the first film to planarize the first film and remove a second thickness of the first film, the first temperature being lower than the second temperature, the first thickness being greater than the second thickness, and a sum of the first thickness and the second thickness being a total etching thickness of the first film.

## Claims

### Claim 1

A method of making a silicon on insulator (SOI) structure, comprising steps of:
Step S1: providing a bonded structure, the bonded structure comprises the first substrate, the second substrate and the insulating buried layer, the insulating buried layer is positioned between the first substrate and the second substrate;
Step S2: peeling off a layer of removing region of the first substrate from the bonded structure to obtain a first film;
Step S3: at a first temperature, performing a first etching to etch the first film to remove a first thickness of the first film; and
Step S4: at a second temperature, performing a second etching to etch the first film to planarize the first film and remove a second thickness of the first film, the first temperature being lower than the second temperature, the first thickness being greater than the second thickness, and a sum of the first thickness and the second thickness being a total etching thickness of the first film;
wherein
the first etching is performed with parameters of: etching temperature being 900° C. 1000° C., flow of the first carrier gas being 40 slm˜120 slm, and volume fraction of the first etching gas being lower than 1%;
the second etching is performed with parameters of: etching temperature being higher than 1050° C., flow of the second carrier gas being 40 slm˜120 slm, volume fraction of the second etching gas being lower than 0.5%, and volume fraction of the second etching gas being lower than volume fraction of the first etching gas; and
both of the first etching gas and the second etching gas comprise HCl gas.

### Claim 2 (depends on 1)

The method according to claim 1, wherein Step S3 comprises: performing the first etching to etch the first film to remove the first thickness of the first film with a first etching gas, using hydrogen as a first carrier gas, in a rapid thermal annealing (RTA) equipment or an epitaxy equipment.

### Claim 3 (depends on 1)

The method according to claim 1, wherein a proportion of the first thickness to the total etching thickness is no greater than 70%.

### Claim 4 (depends on 1)

The method according to claim 1, wherein Step S4 comprises: performing the second etching to planarize the first film to remove the second thickness of the first film with a second etching gas, using hydrogen as a second carrier gas, in a rapid thermal annealing (RTA) equipment or an epitaxy equipment.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the bonded structure is formed with steps comprises:
providing the first substrate and the second substrate;
growing a first oxide layer on a front surface of the first substrate;
performing ion implantation from the front surface of the first substrate toward the first substrate to obtain a damaged layer; and
bonding the front surface of the first substrate and a front surface of the second substrate to form the bonded structure.

### Claim 6 (depends on 5)

The method according to claim 5, wherein when thickness of the insulating buried layer is smaller than 4000 Å, the insulating buried layer comprise the first oxide layer.

### Claim 7 (depends on 5)

The method according to claim 5, wherein when thickness of the insulating buried layer is greater than 4000 Å, the insulating buried layer comprise the first oxide layer and a second oxide layer, and during the growth of the first oxide layer on the front surface of the first substrate, the second oxide layer is formed on the front surface of the second substrate.

### Claim 8 (depends on 7)

The method according to claim 7, wherein thickness of the first oxide layer is 100 Å-4000 Å, and thickness of the second oxide layer is 100 Å-30000 Å.

### Claim 9 (depends on 5)

The method according to claim 5, wherein Step S2 comprises:
performing a first annealing for the bonded structure, peeling off the bonded structure along with the damaged layer, and obtain the SOI structure constructed by the first film on the insulating buried layer, the second substrate, the insulating buried layer and the first film;
performing a second annealing for the SOI structure; and
rinsing a surface of the first film.

### Claim 10 (depends on 9)

The method according to claim 9, wherein the second annealing is performed in oxygen-containing atmosphere, and a layer of silicon oxide is grown on the surface of the first film; and the rinsing step is used to remove the layer of silicon oxide.

### Claim 11 (depends on 1)

A silicon on insulator (SOI) structure, made with the method according to claim 1.