# US 10,770,349 B2 · Critical dimension control for self-aligned contact patterning

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- Number: US 10,770,349 B2
- Document ID: US10770349B2
- Status: Granted
- Kind: B2
- Application number: 15/902,362
- Filed: 2018-02-22
- Published: 2018-08-23
- Granted: 2020-09-08
- Earliest claimed: 2017-02-22
- Assignees: Applied Materials, Inc.
- Applicants: Applied Materials, Inc.
- Inventors: Abhijit Basu Mallick; Ziqing Duan
- Web page: https://patentgrep.com/patent/US10770349B2

## CPC

- H10W 20/069: {by forming self-aligned vias or self-aligned contact plugs}
- H10P 14/432: {using selective deposition}
- H10P 14/69393: {the material containing tantalum, e.g. Ta2O5}
- H10W 20/056: {by filling conductive material into holes, grooves or trenches}
- H10W 20/057: {by selectively depositing, e.g. by using selective CVD or plating}
- H10W 20/0693: {by forming self-aligned vias}
- H10W 20/0696: {by using sacrificial placeholders, e.g. using sacrificial plugs}
- H10W 20/076: {in via holes or trenches}
- H10P 14/6314: {of a metallic layer}
- H10P 14/6316: {Formation by nitridation, e.g. nitridation of the substrate}
- H10P 50/285: {of materials not containing Si, e.g. PZT or Al2O3}
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

Processing methods to create self-aligned contacts are described. A conformal liner can be deposited in a feature in a substrate surface leaving a gap between the walls of the liner. A tungsten film can be deposited in the gap of the liner and volumetrically expanded. The expanded film can be removed and replaced with a contact material to a make a contact. In some embodiments, a conformal tungsten film can be formed in the feature leaving a gap between the walls. A dielectric can be deposited in the gap and the conformal tungsten film can be volumetrically expanded to grow two pillars. The pillars can be removed and replaced with a contact material to make two contacts.

## Claims

### Claim 1

A method of forming a contact pattern, the method comprising:
providing a substrate having a substrate surface with a feature, the feature having sidewalls and a bottom;
forming a conformal liner in the feature, leaving a gap between the conformal liner on the sidewalls of the feature;
filling the gap between the sidewalls of the conformal liner with tungsten; and
volumetrically expanding the tungsten by nitridation to grow a pillar of tungsten nitride extending above the substrate surface.

### Claim 2 (depends on 1)

The method of claim 1, wherein the tungsten is deposited by atomic layer deposition.

### Claim 3 (depends on 1)

The method of claim 1, wherein volumetrically expanding the tungsten grows a pillar of tungsten nitride straight up to extend above the substrate surface.

### Claim 4 (depends on 1)

The method of claim 1, wherein the gap between the sidewalls of the conformal liner has a width less than or equal to about 10 nm.

### Claim 5 (depends on 1)

The method of claim 1, wherein the conformal liner comprises a low-k dielectric.

### Claim 6 (depends on 5)

The method of claim 5, wherein the conformal liner comprises multiple layers, wherein at least one layer is a low-k dielectric.

### Claim 7 (depends on 6)

The method of claim 6, wherein at least one layer of the multiple layers comprises TaN.

### Claim 8 (depends on 5)

The method of claim 5, wherein the low-k dielectric comprises one or more of SiN, SiCN, SiO2, TiN, TaN, TiSiN, Si or C.

### Claim 9 (depends on 1)

The method of claim 1, wherein the conformal liner has an average thickness in the range of about 2 nm to about 15 nm.

### Claim 10 (depends on 9)

The method of claim 9, wherein the feature has a width in the range of about 15 nm to about 40 nm and the conformal liner has an average thickness sufficient to form a gap in the conformal liner with a width in the range of about 5 nm to about 15 nm.

### Claim 11 (depends on 1)

The method of claim 1, further comprising removing the tungsten nitride pillar to leave an opening and depositing a contact material in the opening.

### Claim 12

A method of forming a contact pattern, the method comprising:
providing a substrate having a substrate surface with a feature therein, the feature having sidewalls and a bottom;
forming a conformal tungsten film in the feature, leaving a gap between the tungsten film on the sidewalls of the feature;
filling the gap in the tungsten film with a gapfill material; and
volumetrically expanding the tungsten by nitridation to grow two pillars of tungsten nitride extending above the substrate surface.

### Claim 13 (depends on 12)

The method of claim 12, further comprising removing the pillars to leave two openings and depositing a contact material in the openings.

### Claim 14 (depends on 12)

The method of claim 12, wherein the conformal tungsten film is formed by atomic layer deposition.

### Claim 15 (depends on 12)

The method of claim 12, wherein volumetrically expanding the tungsten grows pillars of tungsten nitride straight up to extend above the substrate surface.

### Claim 16 (depends on 12)

The method of claim 12, wherein the conformal tungsten film has an average thickness in the range of about 2 nm to about 10 nm.

### Claim 17 (depends on 12)

The method of claim 12, wherein the conformal tungsten film has an average thickness in the range of about 2 nm to about 5 nm and the conformal tungsten film is substantially continuous.

### Claim 18 (depends on 12)

The method of claim 12, wherein the gapfill material comprises a dielectric.

### Claim 19 (depends on 12)

The method of claim 12, wherein the feature has a width in the range of about 10 nm to about 30 nm.

### Claim 20

A method of forming a contact pattern, the method comprising:
providing a substrate having a substrate surface with a feature therein, the feature having sidewalls and a bottom and a width in the range of about 10 nm to about 30 nm;
forming a conformal tungsten film in the feature by atomic layer deposition leaving a gap between the tungsten film on the sidewalls of the feature, the conformal tungsten film having an average thickness in the range of about 2 nm to about 10 nm;
filling the gap in the conformal tungsten film with a gapfill material comprising a dielectric;
volumetrically expanding the tungsten by nitridation to grow two pillars of tungsten nitride straight up to extend above the substrate surface;
removing the two pillars of tungsten nitride to leave two openings; and
depositing a contact material in the openings.