# US 9,437,484 B2 · Etch stop layer in integrated circuits

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- Number: US 9,437,484 B2
- Document ID: US9437484B2
- Status: Granted
- Kind: B2
- Application number: 14/689,929
- Filed: 2015-04-17
- Published: 2016-04-21
- Granted: 2016-09-06
- Earliest claimed: 2014-10-17
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Company, Ltd.
- Inventors: Shiu-Ko JangJian; Tsung-Hsuan Hong; Chun Che Lin; Chih-Nan Wu
- Web page: https://patentgrep.com/patent/US9437484B2

## CPC

- H10W 20/42: Vias, e.g. via plugs
- H10W 20/056: {by filling conductive material into holes, grooves or trenches}
- H10W 20/074: {of dielectric parts comprising thin functional dielectric layers, e.g. dielectric etch-stop, barrier, capping or liner layers}
- H10W 20/075: {of multilayered thin functional dielectric layers}
- H10W 20/077: {on sidewalls or on top surfaces of conductors (H10W20/076 takes precedence)}
- H10W 20/081: {by forming openings in the dielectric parts}
- H10W 20/084: {for dual-damascene structures}
- H10W 20/096: {by contacting with gases, liquids or plasmas}
- H10W 20/425: {Barrier, adhesion or liner layers}
- H10W 20/47: comprising two or more dielectric layers having different properties, e.g. different dielectric constants
- H10W 20/48: Insulating materials thereof
- H10W 20/037: {the barrier, adhesion or liner layers being on top of a main fill metal}
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

An integrated circuit structure includes a dielectric layer and an etch stop layer. The etch stop layer includes a first sub layer including a metal nitride over the first dielectric layer, and a second sub layer overlying or underlying the first sub layer. The second sub layer includes a metal compound comprising an element selected from carbon and oxygen, and is in contact with the first sub layer.

## Claims

### Claim 1

A method comprising:
forming an etch stop layer over a first dielectric layer, wherein the forming the etch stop layer comprises:
forming a metal nitride layer over the first dielectric layer; and
performing a treatment on the metal nitride layer using an oxygen-containing gas or a carbon-containing gas, wherein a top surface layer of the metal nitride layer is converted to a second sub layer of the etch stop layer, and a bottom layer of the metal nitride layer remains untreated to act as a first sub layer of the etch stop layer;
forming a second dielectric layer over the etch stop layer;
etching the second dielectric layer, wherein the etching is stopped on the etch stop layer; and
etching through the etch stop layer.

### Claim 2 (depends on 1)

The method of claim 1, wherein the forming the etch stop layer further comprises:
before the forming the metal nitride layer, forming a third sub layer of the etch stop layer over and contacting the first dielectric layer, with the metal nitride layer being over and contacting the third sub layer, wherein the third sub layer comprises a metal carbide.

### Claim 3 (depends on 2)

The method of claim 2, wherein the third sub layer and the metal nitride layer comprise a same metal.

### Claim 4 (depends on 2)

The method of claim 2, wherein the treatment is performed using the carbon-containing gas, and the second sub layer comprises a metal carbo-nitride.

### Claim 5 (depends on 2)

The method of claim 2, wherein the treatment is performed using the oxygen-containing gas, and the second sub layer comprises a metal oxynitride.

### Claim 6 (depends on 2)

The method of claim 2, wherein the metal nitride layer is formed as substantially free from carbon and nitrogen.

### Claim 7

A method comprising:
forming an etch stop layer over a first dielectric layer, the forming the etch stop layer comprising:
depositing a first sub layer comprising a metal-and-carbon-containing compound over the first dielectric layer;
forming a second sub layer overlying the first sub layer, wherein the second sub layer comprises metal nitride; and
forming a third sub layer overlying the second sub layer, wherein the third sub layer comprises a metal compound comprising an element selected from carbon and oxygen;
forming a second dielectric layer over the etch stop layer;
etching through the second dielectric layer and the etch stop layer; and
forming a via extending into the second dielectric layer and the etch stop layer.

### Claim 8 (depends on 7)

The method of claim 7, wherein the forming the second sub layer comprises depositing metal nitride.

### Claim 9 (depends on 7)

The method of claim 7, wherein the forming the second sub layer and the forming the third sub layer comprise:
depositing a metal nitride layer; and
treating a top portion of the metal nitride layer using an oxygen-containing gas or a carbon-containing gas to form the third sub layer, with the third sub layer being a metal carbo-nitride layer or a metal oxynitride layer, wherein a bottom portion of the metal nitride layer remains not treated as the second sub layer.

### Claim 10 (depends on 9)

The method of claim 9, wherein the treating is performed using the carbon-containing gas, and the third sub layer is the metal carbo-nitride layer.

### Claim 11 (depends on 9)

The method of claim 9, wherein the treating is performed using the oxygen-containing gas, and the third sub layer is the metal oxynitride layer.

### Claim 12 (depends on 7)

The method of claim 7, wherein the forming the second sub layer and the forming the third sub layer comprise:
depositing a metal nitride layer as the second sub layer; and
depositing a metal carbo-nitride layer as the third sub layer.

### Claim 13 (depends on 7)

The method of claim 7, wherein the forming the second sub layer and the forming the third sub layer comprise:
depositing a metal nitride layer as the second sub layer; and
depositing a metal oxynitride layer as the third sub layer.

### Claim 14 (depends on 7)

The method of claim 7, wherein the first sub layer is substantially free from oxygen.

### Claim 15 (depends on 7)

The method of claim 7, wherein the second sub layer is substantially free from oxygen and carbon.

### Claim 16

A method comprising:
forming a metal line in a first low-k dielectric layer;
forming a metal capping layer over and contacting the metal line;
forming an etch stop layer over the metal capping layer and the first low-k dielectric layer, the forming the etch stop layer comprising:
depositing a carbon-containing dielectric layer as a first sub layer, with the first sub layer contacting the metal capping layer, wherein the first sub layer is free from oxygen;
depositing a metal nitride layer as a second sub layer over the first sub layer, wherein the metal nitride layer is substantially free from oxygen and carbon; and
performing a treatment on a top portion of the second sub layer to convert the top portion into a third sub layer;
forming a second low-k dielectric layer over and contacting the etch stop layer;
etching-through the second low-k dielectric layer and the etch stop layer; and
forming a via extending into the second low-k dielectric layer and the etch stop layer, with a bottom of the via in contact with the metal capping layer.

### Claim 17 (depends on 16)

The method of claim 16, wherein the treatment is performed using an oxygen-containing gas.

### Claim 18 (depends on 16)

The method of claim 16, wherein the treatment is performed using a carbon-containing gas.

### Claim 19 (depends on 16)

The method of claim 16, wherein the treatment comprises a plasma treatment or a thermal treatment.

### Claim 20 (depends on 16)

The method of claim 16, wherein a bottom portion of the second sub layer remains un-treated by the treatment, and remains as a metal nitride layer.