# US 10,312,475 B2 · CVD thin film stress control method for display application

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- Number: US 10,312,475 B2
- Document ID: US10312475B2
- Status: Granted
- Kind: B2
- Application number: 15/613,667
- Filed: 2017-06-05
- Published: 2018-11-15
- Granted: 2019-06-04
- Earliest claimed: 2017-05-15
- Assignees: Applied Materials, Inc.
- Applicants: Applied Materials, Inc.
- Inventors: Tae Kyung Won; Soo Young Choi; Sanjay D. Yadav; Carl A. Sorensen; Chien-Teh Kao; Suhail Anwar; Young Dong Lee
- Web page: https://patentgrep.com/patent/US10312475B2

## CPC

- H10K 77/111: {Flexible substrates}
- H10K 59/873: {Encapsulations}
- H10K 85/111: {comprising aromatic, heteroaromatic, or aryl chains, e.g. polyaniline, polyphenylene or polyphenylene vinylene}
- H10K 71/40: Thermal treatment, e.g. annealing in the presence of a solvent vapour
- H10K 2102/00: Constructional details relating to the organic devices covered by this subclass
- H10K 2102/311: {Flexible OLED}
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES

## Abstract

Embodiments of the present disclosure generally describe a method for depositing a barrier layer of SiN using a high density plasma chemical vapor deposition (HDP-CVD) process, and in particular, controlling a film stress of the deposited SiN layer by biasing the substrate during the deposition process.

## Claims

### Claim 1

A method of forming a film layer, comprising:
heating a substrate, disposed on a substrate support in a processing chamber, to a substrate temperature of below about 100° C.;
flowing a silicon precursor gas and a nitrogen precursor gas into the processing chamber;
forming a high density plasma of the nitrogen precursor gas and the silicon precursor gas;
depositing a silicon nitride layer on the substrate; and
controlling a film stress of the deposited silicon nitride layer by biasing the substrate while depositing the silicon nitride layer, wherein biasing the substrate comprises applying a biasing power to an electrode disposed in or on the substrate support, and wherein the applied biasing power is between about 130 millaWatts and about 2300 millaWatts per cm2 of substrate surface area.

### Claim 2 (depends on 1)

The method of claim 1, wherein the film stress of the silicon nitride layer is controlled by biasing the substrate to have a compressive or tensile stress of less than about 150 MPa.

### Claim 3 (depends on 2)

The method of claim 2, wherein the film stress of the silicon nitride layer is controlled to have a compressive stress of less than about 150 MPa.

### Claim 4 (depends on 2)

The method of claim 2, wherein the silicon nitride layer forms a barrier layer of a thin film encapsulation structure, wherein the thin film encapsulation structure comprises a first barrier layer deposited over an OLED device, an organic buffer layer deposited on the first barrier layer, and the silicon nitride layer deposited on the organic buffer layer, the silicon nitride layer forming a second barrier layer.

### Claim 5 (depends on 4)

The method of claim 4, wherein a thickness of the second barrier layer is less than about 2000 Å.

### Claim 6 (depends on 1)

The method of claim 1, wherein the silicon precursor gas comprises silane (SiH4), disilane (Si2H6), trisilane (Si3H3), tetrasilane (Si4H10), silicon tetrafluoride (SiF4), silicon tetrachloride (SiCl4), dichlorosilane (SiH2Cl2), or mixtures thereof.

### Claim 7 (depends on 1)

The method of claim 1, wherein the nitrogen precursor gas comprises nitrogen gas, ammonia, diazene, hydrazine (N2H4), or mixtures thereof.

### Claim 8 (depends on 1)

The method of claim 1, wherein the high density plasma has an electron density of more than about 1011/cm3.

### Claim 9 (depends on 1)

The method of claim 1, wherein the electrode is coupled to an RF power source having a frequency of between about 200 kHz and about 1 MHz.

### Claim 10 (depends on 9)

The method of claim 9, wherein an RF power supplied by the RF power source is between about 130 millaWatts/cm2 and about 1400 milliWatts/cm2.

### Claim 11 (depends on 1)

The method of claim 1, wherein the high density plasma is formed using an inductively coupled RF plasma source, a linear microwave plasma source, or an electron cyclotron resonance plasma source.

### Claim 12 (depends on 1)

The method of claim 1, wherein a chamber pressure is maintained at below about 1 Torr.

### Claim 13

A method of forming a film layer comprising:
flowing a silicon precursor gas and a nitrogen precursor gas into a processing chamber;
biasing an electrode coupled to a substrate support disposed in the processing chamber;
forming a plasma of the nitrogen precursor gas and the silicon precursor gas, wherein the plasma has an electron density of more than about 1011/cm3;
depositing a silicon nitride layer on a substrate disposed on the substrate support while maintaining a substrate temperature of between about 50° C. and about 150° C.; and
controlling a film stress of the deposited silicon nitride layer by biasing the substrate while depositing the silicon nitride layer, wherein biasing the substrate comprises applying a biasing power to an electrode disposed in or on the substrate support, and wherein the applied biasing power is between about 130 millaWatts and about 2300 millaWatts per cm2 of substrate surface area.

### Claim 14 (depends on 13)

The method of claim 13, wherein the electrode is coupled to an RF power source and wherein the RF power source has a frequency of between about 200 kHz and about 1 MHz.

### Claim 15 (depends on 13)

The method of claim 13, wherein the substrate comprises glass, a flexible polymer, or a combination thereof.

### Claim 16 (depends on 13)

The method of claim 13, wherein the electrode is coupled to an RF power source and wherein the RF power source has a frequency of less than about 10 MHz.

### Claim 17 (depends on 13)

The method of claim 13, wherein the plasma is formed using a microwave plasma source, an inductively coupled plasma source, a linear microwave plasma source, or an electron cyclotron resonance plasma source.

### Claim 18 (depends on 13)

The method of claim 13, wherein the silicon nitride layer forms a barrier layer of a thin film encapsulation structure, wherein
the thin film encapsulation structure comprises:
a first barrier layer deposited over an OLED device;
an organic buffer layer deposited on the first barrier layer; and
the silicon nitride layer is deposited on the organic buffer layer, wherein
the silicon nitride layer forms a second barrier layer, and
each of the first and second barrier layers have a thickness less than about 2000 Å.

### Claim 19

A method of forming a thin film encapsulation structure, comprising:
heating a substrate, disposed on a substrate support in a processing chamber, to a temperature of below about 100° C.;
flowing a silicon precursor gas and a nitrogen precursor gas into the processing chamber;
forming a plasma of the nitrogen precursor gas and the silicon precursor gas, the plasma having an electron density of more than about 1011/cm3;
depositing a silicon nitride layer onto the substrate; and
controlling a film stress of the deposited silicon nitride layer by biasing the substrate while depositing the silicon nitride layer, wherein
biasing the substrate comprises applying a biasing power to an electrode disposed in or on the substrate support,
the applied biasing power is between about 130 millaWatts and about 2300 millaWatts per cm2 of substrate surface area,
the film stress of the deposited silicon nitride layer is controlled to less than about 150 MPa of compressive stress, and
the silicon nitride layer forms a barrier layer of the thin film encapsulation structure, the thin film encapsulation structure comprising a first barrier layer deposited over an OLED device, an organic buffer layer deposited on the first barrier layer, and the silicon nitride layer deposited on the organic buffer layer, the silicon nitride layer forming a second barrier layer having a thickness less than about 2000 Å.