# US 2018/0025940 A1 · Method for removing barrier layer for minimizing sidewall recess

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- Number: US 2018/0025940 A1
- Document ID: US20180025940A1
- Status: Published application
- Kind: A1
- Application number: 15/550,960
- Filed: 2015-02-15
- Published: 2018-01-25
- Earliest claimed: 2015-02-15
- Assignees: ACM Research (Shanghai) Inc.
- Applicants: ACM Research (Shanghai) Inc.
- Inventors: Zhaowei Jia; Jian Wang; Hui Wang
- Web page: https://patentgrep.com/patent/US20180025940A1

## CPC

- H10W 20/054: {by selectively removing parts thereof (H10W20/034 takes precedence)}
- H10P 50/266: {by vapour etching only}
- H10P 74/203: {Structural properties, e.g. testing or measuring thicknesses, line widths, warpage, bond strengths or physical defects}
- H10P 74/238: {comprising acting in response to an ongoing measurement without interruption of processing, e.g. endpoint detection or in-situ thickness measurement}
- H10P 95/064: {the removal being chemical etching}
- H10W 20/062: {by smoothing of conductive parts, e.g. by planarisation}
- H10P 50/73: {using masks for insulating materials}
- H10P 74/23: {characterised by multiple measurements, corrections, marking or sorting processes}
- 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

Provided is a method for removing barrier layer for minimizing sidewall recess. The method comprises the following steps: introduce noble-gas-halogen compound gas and carrier gas into an etching chamber within which a thermal gas phase etching process is being performed for etching a barrier layer (206) on non-recessed areas of an interconnection structure (501); detect an end point of the thermal gas phase etching process (502), if the thermal gas phase etching process reaches the end point end point, then execute the next step; if the thermal gas phase etching process doesn't reach the end point, then return to the previous step; stop introducing the noble-gas-halogen compound gas and the carrier gas to the etching chamber (503).

## Claims

### Claim 1

A method for removing barrier layer for minimizing sidewall recess, comprising:
introducing noble-gas-halogen compound gas and carrier gas into an etching chamber within which a thermal gas phase etching process being performed for etching a barrier layer on non-recessed areas of an interconnection structure;
detecting an end point of the thermal gas phase etching process, executing the next step if the thermal gas phase etching process reaches the end point; returning to the previous step if the thermal gas phase etching process doesn't reach the end point;
stopping introducing the noble-gas-halogen compound gas and the carrier gas into the etching chamber.

### Claim 2 (depends on 1)

The method of claim 1, wherein the flow rate ratio of the carrier gas and the noble-gas-halogen compound gas is 1:1 to 50:1.

### Claim 3 (depends on 1)

The method of claim 1, wherein the partial pressure of the noble-gas-halogen compound gas is 0.01-5 Torr.

### Claim 4 (depends on 1)

The method of claim 1, wherein the molecular weight of the carrier gas is bigger than the molecular weight of the noble-gas-halogen compound gas.

### Claim 5 (depends on 1)

The method of claim 1, wherein the noble-gas-halogen compound gas is one of XeF2, XeF4, XeF6, KrF2.

### Claim 6 (depends on 1)

The method of claim 1, wherein the noble-gas-halogen compound gas is a mixture of at least two of the following: XeF2, XeF4, XeF6 or KrF2.

### Claim 7 (depends on 1)

The method of claim 1, wherein the carrier gas is inert gas.

### Claim 8 (depends on 7)

The method of claim 7, wherein the inert gas is one of Xe, Kr, Ar, Ne, He.

### Claim 9 (depends on 7)

The method of claim 7, wherein the inert gas is a mixture of at least two of the following: Xe, Kr, Ar, Ne or He.

### Claim 10 (depends on 1)

The method of claim 1, wherein the carrier gas is N2.

### Claim 11 (depends on 1)

The method of claim 1, wherein the material of the barrier layer is a layer of Ta, TaN, Ti, TiN, Ru, Co, W, WN or Hf.

### Claim 12 (depends on 1)

The method of claim 1, wherein the interconnection structure is formed on a substrate, the temperature of the substrate is 20-500° C.

### Claim 13 (depends on 1)

The method of claim 1, wherein the pressure of the etching chamber is 0.01-50 Torr.

### Claim 14 (depends on 1)

The method of claim 1, wherein the interconnection structure includes a hard mask layer and at least one dielectric layer, the hard mask layer is removed by the thermal gas phase etching process, the step of detecting an end point of the thermal gas phase etching process further comprises using an Ellipsometer to detect the refractive index of the hard mask layer and the dielectric layer and determining whether the thermal gas phase etching process reaches the end point according to the refractive index detected by the Ellipsometer.

### Claim 15 (depends on 1)

The method of claim 1, wherein the interconnection structure includes a hard mask layer, the hard mask layer is removed by the thermal gas phase etching process, the step of detecting an end point of the thermal gas phase etching process further comprises using an Ellipsometer to detect the thickness of the barrier layer on the non-recessed areas of the interconnection structure and the hard mask layer in real time and determining whether the thermal gas phase etching process reaches the end point according to the thickness of the hard mask layer detected by the Ellipsometer.

### Claim 16 (depends on 1)

The method of claim 1, wherein before introducing the carrier gas into the etching chamber, the noble-gas-halogen compound gas is introduced into the etching chamber for a period of time.

### Claim 17 (depends on 16)

The method of claim 16, wherein the flow of the carrier gas is increased when the thermal gas phase etching process is approximating the end point.

### Claim 18 (depends on 1)

The method of claim 1, wherein after stopping introducing the noble-gas-halogen compound gas into the etching chamber, keep introducing the carrier gas into the etching chamber for a period of time, and then stopping introducing the carrier gas into the etching chamber.