# US 12,002,684 B2 · Methods for chemical mechanical polishing and forming interconnect structure

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- Number: US 12,002,684 B2
- Document ID: US12002684B2
- Status: Granted
- Kind: B2
- Application number: 18/057,728
- Filed: 2022-11-21
- Published: 2023-03-16
- Granted: 2024-06-04
- Earliest claimed: 2020-06-15
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Company Ltd.
- Inventors: Ji Cui; Fu-Ming Huang; Ting-Kui Chang; Tang-Kuei Chang; Chun-Chieh Lin; Wei-Wei Liang; Liang-Guang Chen; Kei-Wei Chen; Hung Yen; Ting-Hsun Chang; Chi-Hsiang Shen; Li-Chieh Wu; Chi-Jen Liu
- Web page: https://patentgrep.com/patent/US12002684B2

## CPC

- H10P 52/403: {of conductive or resistive materials}
- B24B 37/044: {characterised by the composition of the lapping agent}
- B24B 37/107: {in a rotary movement only, about an axis being stationary during lapping}
- C09G 1/02: containing abrasives or grinding agents {(abrasives as such C09K3/14; polishing of semi-conductors H10P52/40)}
- H10W 20/035: {combinations of barrier, adhesion or liner layers, e.g. multi-layered barrier layers}
- H10W 20/062: {by smoothing of conductive parts, e.g. by planarisation}
- H10W 20/077: {on sidewalls or on top surfaces of conductors (H10W20/076 takes precedence)}
- H10W 20/425: {Barrier, adhesion or liner layers}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- B24B: MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING (grinding of gear teeth B23F, of screw-threads B23G1/36; by electro-erosion B23H; abrasive or related blasting B24C; tools for grinding, buffing or sharpening B24D; polishing compositions C09G1/00; abrasives C09K3/14; electrolytic etching or polishing C25F3/00; grinding arrangements for use on assembled railway tracks E01B31/17); DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- C09G: POLISHING COMPOSITIONS (French polish C09F11/00); SKI WAXES
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

A method for CMP includes following operations. A metal stack is received. The metal layer stack includes at least a first metal layer and a second metal layer, and a top surface of the first metal layer and a top surface of the second metal layer are exposed. A protecting layer is formed over the second metal layer. A portion of the first metal layer is etched. The protecting layer protects the second metal layer during the etching of the portion of the first metal layer. A top surface of the etched first metal layer is lower than a top surface of the protecting layer. The protecting layer is removed from the second metal layer.

## Claims

### Claim 1

A method for chemical-mechanical polishing (CMP), comprising:
receiving a metal layer stack in a dielectric structure, wherein the metal layer stack comprises at least a first metal layer and a second metal layer over the first metal layer, and a top surface of the first metal layer and a top surface of the second metal layer being exposed;
forming a protecting layer over the top surface of the second metal layer;
etching a portion of the first metal layer, wherein the protecting layer protects the second metal layer during the etching of the portion of the first metal layer, and a top surface of the etched first metal layer is lower than a top surface of the protecting layer;
removing the protecting layer from the second metal layer; and
removing a portion of the first metal layer, a portion of the second metal layer and a portion of the dielectric structure, wherein a top surface of the first metal layer, a top surface of the second metal layer and a top surface of the dielectric structure form a flush surface.

### Claim 2 (depends on 1)

The method of claim 1, wherein the forming of the protecting layer comprises applying a first composition, and the first composition comprises benzotriazole (BTA), triazole derivatives, thioazole derivatives, and tetrazole derivatives.

### Claim 3 (depends on 1)

The method of claim 1, wherein the etching of the portion of the first metal layer comprises applying a second composition, and the second composition comprises halogen oxoacid or their salts.

### Claim 4 (depends on 3)

The method of claim 3, wherein a process duration of the applying of the second composition is between approximately 15 seconds and approximately 10 minutes.

### Claim 5 (depends on 1)

The method of claim 1, wherein the first metal layer comprises noble metals.

### Claim 6 (depends on 1)

The method of claim 1, wherein the removing of the portion of the first metal layer, the portion of the second metal layer and the portion of the dielectric structure comprises performing a CMP operation.

### Claim 7 (depends on 1)

The method of claim 1, wherein the removing of the protecting layer comprises performing a cleaning operation.

### Claim 8

A method for chemical-mechanical polishing (CMP), comprising:
forming a first metal layer in a dielectric structure and a second metal layer covering the first metal layer;
removing a portion of the second metal layer to expose the first metal layer;
forming a protecting layer over the second metal layer and etching the first metal layer, wherein a top surface of the etched first metal layer is lower than a top surface of the protecting layer;
removing the protecting layer to expose the second metal layer; and
removing a portion of the first metal layer, a portion of the second metal layer and a portion of the dielectric structure, wherein a top surface of the first metal layer, a top surface of the second metal layer and a top surface of the dielectric structure form a flush surface.

### Claim 9 (depends on 8)

The method of claim 8, further comprising applying a mixture to form the protecting layer and to etch the portion of the first metal layer.

### Claim 10 (depends on 9)

The method of claim 9, wherein an etching rate of the mixture on the first metal layer is greater than approximately 5 Å/min.

### Claim 11 (depends on 9)

The method of claim 9, wherein the mixture comprises a first composition to etch the first metal layer and a second composition to form the protecting layer over the second metal layer during the etching of the first metal layer.

### Claim 12 (depends on 11)

The method of claim 11, wherein a concentration of the second composition in the mixture is between approximately 1 ppm and approximately 100,000 ppm.

### Claim 13 (depends on 11)

The method of claim 11, wherein a concentration of the first composition in the mixture is between approximately 100 ppm and approximately 20,000 ppm.

### Claim 14 (depends on 9)

The method of claim 9, wherein a pH of the mixture is between approximately 5.0 and approximately 14.0.

### Claim 15 (depends on 8)

The method of claim 8, further comprising performing a CMP operation to remove the portion of the second metal layer to expose the first metal layer.

### Claim 16 (depends on 8)

The method of claim 8, further comprising performing a CMP operation to remove the portion of the first metal layer, the portion of the second metal layer and the portion of the dielectric structure.

### Claim 17

A method for forming an interconnect structure, comprising:
receiving a dielectric structure having an opening formed therein;
forming a liner covering a bottom and sidewalls of the opening and covering a top surface of the dielectric structure;
filling the opening with a conductive layer, wherein the conductive layer covers the liner;
removing a portion of the conductive layer to expose the liner;
applying a mixture to etch the liner from the top surface of the dielectric structure and form a protecting layer over the conductive layer during the etching of the liner, wherein a top surface of the etched liner is lower than a top surface of the protecting layer; and
removing a portion of the conductive layer, a portion of the liner and a portion of the dielectric structure to form an interconnect structure in the dielectric structure, wherein a top surface of the conductive layer, a top surface of the liner and a top surface of the dielectric structure form a flush surface.

### Claim 18 (depends on 17)

The method of claim 17, wherein the liner has a surface exposed to the mixture, and a ratio of the surface area of the liner to the surface area of the dielectric structure is greater than approximately 5%.

### Claim 19 (depends on 17)

The method of claim 17, wherein the mixture comprises a first composition and a second composition, the first composition removes the liner, and the second composition forms the protecting layer over the conductive layer during the removal of the liner.

### Claim 20 (depends on 17)

The method of claim 17, wherein the liner and the conductive layer comprise different metals.