# US 10,504,717 B2 · Integrated system and method for source/drain engineering

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- Number: US 10,504,717 B2
- Document ID: US10504717B2
- Status: Granted
- Kind: B2
- Application number: 15/417,496
- Filed: 2017-01-27
- Published: 2018-03-22
- Granted: 2019-12-10
- Earliest claimed: 2016-09-16
- Assignees: Applied Materials, Inc.
- Applicants: Applied Materials, Inc.
- Inventors: Chun Yan; Xinyu Bao; Melitta Manyin Hon; Hua Chung; Schubert S. Chu
- Web page: https://patentgrep.com/patent/US10504717B2

## CPC

- H10P 70/20: {Cleaning during device manufacture}
- H10D 30/024: {of fin field-effect transistors [FinFET]}
- H10D 62/021: {Forming source or drain recesses by etching e.g. recessing by etching and then refilling}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

Implementations described herein generally provide a method of processing a substrate. Specifically, the methods described are used for cleaning and etching source/drain regions on a silicon substrate in preparation for precise Group IV source/drain growth in semiconductor devices. Benefits of this disclosure include precise fin size control in devices, such as 10 nm FinFET devices, and increased overall device yield. The method of integrated clean and recess includes establishing a low pressure processing environment in the processing volume, and maintaining the low pressure processing environment while flowing a first gas over a substrate in a processing volume, depositing a salt on the substrate, heating the processing volume to greater than 90° C., purging the processing volume with a second inert gas, and recessing a source/drain region disposed on the substrate.

## Claims

### Claim 1

A method of processing a workpiece, comprising:
delivering a first gas to a processing volume while maintaining a first pressure in the processing volume;
depositing a NH4F salt on a workpiece in the processing volume while maintaining a second pressure in the processing volume;
heating the workpiece to greater than 90° C. while maintaining the second pressure in the processing volume;
purging the processing volume with a second gas while maintaining the first pressure in the processing volume; and
recessing a source/drain region of a device disposed on the workpiece while maintaining the first pressure in the processing volume, wherein
the second pressure in higher than the first pressure.

### Claim 2 (depends on 1)

The method of claim 1, wherein the device has sub-10 nm trenches.

### Claim 3 (depends on 1)

The method of claim 1, wherein a fin layer is disposed on the source/drain region, further comprising recessing the fin layer.

### Claim 4 (depends on 1)

The method of claim 1, wherein the processing volume is defined by an inductively coupled plasma (ICP) plasma reactor chamber.

### Claim 5 (depends on 1)

The method of claim 1, wherein the first gas is a hydrogen argon gas mixture.

### Claim 6 (depends on 5)

The method of claim 5, wherein the hydrogen is flowed at a rate of between 10-500 sccm, and the argon is flowed at a rate of between 300-1000 sccm.

### Claim 7 (depends on 1)

The method of claim 1, further comprising controlling ion energy near the workpiece with low RF source power between 200-800 watts.

### Claim 8 (depends on 1)

The method of claim 1, wherein the first pressure is between 5 mT to 50 mT in the processing volume.

### Claim 9 (depends on 1)

The method of claim 1, further comprising maintaining a temperature of the processing volume at between 20° C. and 40° C.

### Claim 10 (depends on 1)

The method of claim 1, further comprising maintaining an ion energy of the processing volume at less than 50 electronvolt.

### Claim 11 (depends on 1)

The method of claim 1, wherein depositing the NH4F salt on the workpiece comprises:
delivering a NH3/NF3/Ar gas mixture to the processing volume; and
reacting the gas mixture with a plasma in the processing volume.

### Claim 12 (depends on 11)

The method of claim 11, wherein the argon (Ar) is flowed at a rate of 500-1200 sccm, the ammonia (NH3) is flowed at a rate of 10-100 sccm, and the NF3 is flowed at a rate of 5-20 sccm.

### Claim 13 (depends on 1)

The method of claim 1, wherein heating the workpiece to greater than 90° C. occurs for greater than 1 minute.

### Claim 14 (depends on 1)

The method of claim 1, wherein the second gas is a H2/Ar plasma mixture.

### Claim 15 (depends on 1)

The method of claim 1, wherein recessing a source/drain region includes etching the source/drain region 1-2 nm.

### Claim 16 (depends on 1)

The method of claim 1, wherein the second pressure in between 200 mT to 900 mT in the processing volume.