# US 10,501,660 B2 · Method of selectively removing tungsten over silicon oxide

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- Number: US 10,501,660 B2
- Document ID: US10501660B2
- Status: Granted
- Kind: B2
- Application number: 16/297,745
- Filed: 2019-03-11
- Published: 2019-07-04
- Granted: 2019-12-10
- Earliest claimed: 2016-03-01
- Assignees: UWIZ Technology Co., Ltd.
- Applicants: UWIZ Technology Co., Ltd.
- Inventors: Yun-Lung Ho; Chung-Wei Chiang; Song-Yuan Chang; Ming-Hui Lu; Ming-Che Ho
- Web page: https://patentgrep.com/patent/US10501660B2

## CPC

- C09G 1/02: containing abrasives or grinding agents {(abrasives as such C09K3/14; polishing of semi-conductors H10P52/40)}
- H10P 52/403: {of conductive or resistive materials}
- B24B 37/24: characterised by the composition or properties of the pad materials
- C09G: POLISHING COMPOSITIONS (French polish C09F11/00); SKI WAXES
- 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

## Abstract

Provided is a slurry composition including abrasive particles, halogen oxide, and nitroxide compound. The combination of halogen oxide and nitroxide compound has a synergistic effect to remove a substrate containing tungsten and silicon oxide. Moreover, a use of the slurry composition and a polishing method using the slurry composition are provided.

## Claims

### Claim 1

A method of selectively removing tungsten over silicon oxide, the method comprising:
providing a substrate having a tungsten layer directly disposed in and over a silicon oxide layer; and
selectively removing the tungsten layer over the silicon oxide layer to leave the tungsten layer in the silicon oxide layer by chemical mechanical polishing using a slurry, wherein the slurry comprises:
acidic water;
abrasive particles;
a halogen oxide, wherein the halogen oxide is a sodium salt or a potassium salt of chlorate, bromate, iodate, hypochlorite, or any combinations thereof; and
a nitroxide compound, wherein the nitroxide compound is N-methylmorpholine-N-oxide (NMO), 2-mercapto pyridine oxide, trimethyl amine oxide, or any combinations thereof, and the combination of the halogen oxide and the nitroxide compound produce a synergistic effect on the removing rate of the tungsten, compared with using the halogen oxide or the nitroxide compound alone.

### Claim 2 (depends on 1)

The method of claim 1, wherein the halogen oxide has a concentration of the halogen oxide is 100-10000 ppm.

### Claim 3 (depends on 1)

The method of claim 1, wherein the nitroxide compound has a concentration of 300-3000 ppm.

### Claim 4 (depends on 1)

The method of claim 1, wherein the abrasive particles are selected from colloidal silicon oxide, fumed silicon oxide, nano aluminum oxide, or a combination of any two or more of the above.

### Claim 5 (depends on 1)

The method of claim 1, wherein a content of the abrasive particles is 0.5-10 wt %.

### Claim 6 (depends on 1)

The method of claim 1, wherein the slurry has a pH value of 2-6.

### Claim 7 (depends on 1)

The method of claim 1, wherein the slurry further comprises a water-soluble starch having a molecular weight less than 8000.

### Claim 8 (depends on 7)

The method of claim 7, wherein a content of the water-soluble starch is 100-500 ppm.