# US 10,121,649 B2 · Cleaning method of semiconductor wafer

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- Number: US 10,121,649 B2
- Document ID: US10121649B2
- Status: Granted
- Kind: B2
- Application number: 12/592,706
- Filed: 2009-12-01
- Published: 2010-06-10
- Granted: 2018-11-06
- Earliest claimed: 2008-12-04
- Assignees: Siltronic AG
- Applicants: Teruo Haibara
- Inventors: Teruo Haibara
- Web page: https://patentgrep.com/patent/US10121649B2

## CPC

- H10P 70/56: {Cleaning of wafer backside}
- B08B 3/003: {Cleaning involving contact with foam}
- B08B 3/102: {with means for agitating the liquid (by agitating the container B08B3/042, B08B3/044, B08B3/045, B08B3/06)}
- B08B 3/12: by sonic or ultrasonic vibrations
- H10P 70/15: {by wet cleaning only (H10P70/52 takes precedence)}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- B08B: CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL

## Abstract

A wax removal method uniformly removes wax adhering to a wafer surface and reduces the problems of re-adhesion of particles and filter clogging of a cleaning bath during cleaning. The method uses cleaning liquid which contains microbubbles.

## Claims

### Claim 1

A cleaning method of removing wax which is adhered to a semiconductor wafer surface, by using a cleaning liquid, the cleaning method comprising:
introducing a gas to the cleaning liquid by using a microbubble generating device in order to generate microbubbles in the cleaning liquid, and immersing a semiconductor wafer in the cleaning liquid which contains the microbubbles generated by the gas to clean a surface of the semiconductor wafer, wherein wax adhering to the surface of the semiconductor wafer is uniformly removed while dissolving the wax in the cleaning liquid without exfoliating the wax as a solid material,
wherein the cleaning liquid is an aqueous liquid containing an alkaline component and a surfactant component, wherein the alkaline component is quaternary ammonium hydroxide, and wherein surfactant component is limited to surfactants selected from the group consisting of tetraalkylammonium salts, alkylpyridinium salts, and amine salts.

### Claim 2 (depends on 1)

The cleaning method of claim 1, wherein the semiconductor wafer is a silicon wafer.

### Claim 3 (depends on 1)

The cleaning method of claim 1, wherein the microbubbles are formed by introducing into the cleaning liquid at least one or more gases selected from the group consisting of air, hydrogen, helium, nitrogen, oxygen, argon, and mixtures thereof.

### Claim 4 (depends on 1)

The method of claim 1, wherein a nozzle of a microbubble generating device is positioned in a cleaning container to supply microbubbles.

### Claim 5 (depends on 4)

The cleaning method of claim 4, wherein the nozzle is positioned at a bottom or side location of the cleaning container.

### Claim 6 (depends on 1)

The cleaning method of claim 1, wherein ultrasonic waves are introduced into the cleaning liquid.

### Claim 7 (depends on 1)

The cleaning method of claim 1, wherein the wafer is a bare wafer having no microelectronic devices fabricated thereon.

### Claim 8 (depends on 1)

The cleaning method of claim 1, wherein the microbubbles are air microbubbles.

### Claim 9 (depends on 1)

The cleaning method of claim 1, wherein the wax is present as a contiguous coating on an entire surface of the wafer.

### Claim 10

A cleaning method of removing wax which is adhered to a semiconductor wafer surface, by using a cleaning liquid, the cleaning method comprising:
introducing a gas to the cleaning liquid by using a microbubble generating device in order to generate microbubbles in the cleaning liquid, and immersing a semiconductor wafer in the cleaning liquid which contains the microbubbles generated by the gas to clean a surface of the semiconductor wafer, wherein wax adhering to the surface of the semiconductor wafer is uniformly removed while dissolving the wax in the cleaning liquid without exfoliating the wax as a solid material;
wherein the cleaning liquid comprises an alkaline component and a surfactant component wherein the surfactant component is limited to surfactants selected from the group consisting of tetraalkylammonium salts, alkylpyridinium salts, and amine salts and wherein the alkaline component comprises at least one tetraalkylammonium hydroxide.