# US 10,312,137 B2 · Hardmask layer for 3D NAND staircase structure in semiconductor applications

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- Number: US 10,312,137 B2
- Document ID: US10312137B2
- Status: Granted
- Kind: B2
- Application number: 15/175,880
- Filed: 2016-06-07
- Published: 2017-12-07
- Granted: 2019-06-04
- Earliest claimed: 2016-06-07
- Assignees: Applied Materials, Inc.
- Applicants: Applied Materials, Inc.
- Inventors: Eswaranand Venkatasubramanian; Susmit Singha Roy; Pramit Manna; Abhijit Basu Mallick
- Web page: https://patentgrep.com/patent/US10312137B2

## CPC

- H10W 20/089: {using processes for implementing desired shapes or dispositions of the openings, e.g. double patterning}
- H10B 41/27: the channels comprising vertical portions, e.g. U-shaped channels
- H10B 41/35: with a cell select transistor, e.g. NAND
- H10B 43/27: the channels comprising vertical portions, e.g. U-shaped channels
- H10B 43/35: with cell select transistors, e.g. NAND
- H10P 14/6336: {in the presence of a plasma [PECVD]}
- H10P 14/68: Organic materials, e.g. photoresists
- H10P 50/73: {using masks for insulating materials}
- H10P 76/405: {characterised by their composition, e.g. multilayer masks}
- H10P 76/4083: {characterised by their behaviours during the lithography processes, e.g. soluble masks or redeposited masks}
- H10P 76/4085: {characterised by the processes involved to create the masks}
- H10P 76/4088: {Processes for improving the resolution of the masks}
- H10W 20/056: {by filling conductive material into holes, grooves or trenches}
- H10W 20/42: Vias, e.g. via plugs
- H10W 20/435: {Cross-sectional shapes or dispositions of interconnections}
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- H10B: ELECTRONIC MEMORY DEVICES
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

Embodiments of the present disclosure provide an apparatus and methods for forming a hardmask layer that may be utilized to transfer patterns or features to a film stack with accurate profiles and dimension control for manufacturing three dimensional (3D) stacked semiconductor devices. In one embodiment, a method of forming a hardmask layer on a substrate includes forming a seed layer comprising boron on a film stack disposed on a substrate by supplying a seed layer gas mixture in a processing chamber, forming a transition layer comprising born and tungsten on the seed layer by supplying a transition layer gas mixture in the processing chamber, and forming a bulk hardmask layer on the transition layer by supplying a main deposition gas mixture in the processing chamber.

## Claims

### Claim 1

A method of forming a hardmask layer on a substrate comprises:
forming a seed layer comprising boron on a film stack disposed on a substrate by supplying a seed layer gas mixture in a processing chamber, wherein the seed layer gas mixture comprises at least a boron containing gas and a nitrogen containing gas;
forming a gradient transition layer comprising boron and tungsten on the seed layer by supplying a transition layer gas mixture in the same processing chamber, wherein the transition layer gas mixture is supplied to the processing chamber by ramping down a gas flow rate of the boron containing gas while maintaining a steady gas flow rate of the nitrogen containing gas to form the transition layer, and gradually ramping up a gas flow rate of a tungsten containing gas in the transition layer gas mixture; and
forming a bulk hardmask layer comprising tungsten on the transition layer by supplying a deposition gas mixture in the same processing chamber, wherein the nitrogen containing gas is continuously supplied at the steady gas flow rate while forming the bulk hardmask layer.

### Claim 2 (depends on 1)

The method of claim 1, wherein the film stack further comprises a first layer and a second layer repeatedly formed in the film stack.

### Claim 3 (depends on 2)

The method of claim 2, wherein the first layer is a silicon oxide layer and the second layer is a silicon nitride layer.

### Claim 4 (depends on 1)

The method of claim 1, wherein the transition layer has a higher tungsten concentration with the increase of a thickness of the transition layer.

### Claim 5 (depends on 1)

The method of claim 1, wherein a gas flow rate of the tungsten containing gas is ramped up in the transition gas mixture while the gas flow rate of the boron containing gas is ramped down.

### Claim 6 (depends on 1)

The method of claim 1, wherein the forming the bulk hardmask layer further comprises:
steadily supplying the tungsten containing gas in the processing chamber.

### Claim 7 (depends on 4)

The method of claim 4, wherein forming the seed layer further comprises:
steadily supplying the boron containing gas and the nitrogen containing gas in the processing chamber.

### Claim 8 (depends on 1)

The method of claim 1, wherein the film stack includes repeating layer structures formed in three dimensional NAND memory devices.

### Claim 9 (depends on 4)

The method of claim 4, wherein forming the seed layer further comprises supplying a hydrogen containing gas into the processing chamber.

### Claim 10 (depends on 4)

The method of claim 4, wherein the boron containing gas is B2H6 and the nitrogen containing gas is at least one of N2 and NH3.

### Claim 11 (depends on 1)

The method of claim 1, wherein the tungsten containing gas is WF6.

### Claim 12 (depends on 1)

The method of claim 1, wherein the seed layer is a boron nitride layer and the transition layer is a boron tungsten nitride layer and the bulk hardmask layer is a tungsten nitride layer.

### Claim 13

A method of forming a hardmask layer comprising:
supplying a gas mixture including at least a boron containing gas and a nitrogen containing gas onto a surface of a substrate disposed in a processing chamber to form a seed layer on the substrate;
ramping down the boron containing gas and ramping up a tungsten containing gas supplied in the gas mixture while maintaining a steady flow of the nitrogen containing gas into the same processing chamber to form a gradient transition layer on the seed layer; and
continuously supplying the tungsten containing gas in the gas mixture until the tungsten containing gas reaching to a predetermined flow rate and maintaining the tungsten containing gas at a steady predetermined flow rate to form a bulk hardmask layer comprising tungsten in the same processing chamber, wherein the nitrogen containing gas is continuously supplied at the steady gas flow rate while maintaining the tungsten containing gas at the steady predetermined flow rate.

### Claim 14 (depends on 13)

The method of claim 13, wherein the seed layer is a boron nitride layer, the transition layer is a boron tungsten nitride layer, and the bulk hardmask layer is a tungsten nitride layer.