# US 8,771,429 B2 · Supercritical drying method for semiconductor substrate and supercritical drying apparatus

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- Number: US 8,771,429 B2
- Document ID: US8771429B2
- Status: Granted
- Kind: B2
- Application number: 13/420,870
- Filed: 2012-03-15
- Published: 2013-01-24
- Granted: 2014-07-08
- Earliest claimed: 2011-07-19
- Assignees: Kabushiki Kaisha Toshiba; Tokyo Electron Limited
- Applicants: Linan Ji; Hidekazu Hayashi; Hiroshi Tomita; Hisashi Okuchi; Yohei Sato; Takayuki Toshima; Mitsuaki Iwashita; Kazuyuki Mitsuoka; Gen You; Hiroki Ohno; Takehiko Orii
- Inventors: Linan Ji; Hidekazu Hayashi; Hiroshi Tomita; Hisashi Okuchi; Yohei Sato; Takayuki Toshima; Mitsuaki Iwashita; Kazuyuki Mitsuoka; Gen You; Hiroki Ohno; Takehiko Orii
- Web page: https://patentgrep.com/patent/US8771429B2

## CPC

- H10P 95/00: Generic processes or apparatus for manufacture or treatments not covered by the other groups of this subclass
- F26B 21/35: Temperature; Pressure
- F26B 21/40: using gases other than air
- F26B 23/028: {using solid fuel; burning the dried product}
- H10P 70/15: {by wet cleaning only (H10P70/52 takes precedence)}
- H10P 70/20: {Cleaning during device manufacture}
- H10P 70/80: {Cleaning only by supercritical fluids}
- H10P 72/0408: {for drying}
- F26B 2200/04: Garbage
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- F26B: DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM (drying devices for combines A01D41/133; racks for drying fruit or vegetables A01F25/12; drying foodstuffs A23; drying hair A45D20/00; body-drying implements A47K10/00; drying household articles A47L; drying gases or vapours B01D; chemical or physical processes for dewatering or like separating liquids from solids B01D43/00; centrifugal apparatus B04; drying ceramics C04B33/30; drying yarns or fabrics in association with some other form of treatment D06C; drying frames for laundry without heating or positive air circulation, domestic laundry-or spin-driers, wringing or hot pressing laundry D06F; furnaces, kilns, ovens F27)

## Abstract

According to one embodiment, a supercritical drying method for a semiconductor substrate, comprises introducing the semiconductor substrate into a chamber in a state, a surface of the semiconductor substrate being wet with alcohol, substituting the alcohol on the semiconductor substrate with a supercritical fluid of carbon dioxide by impregnating the semiconductor substrate to the supercritical fluid in the chamber, and discharging the supercritical fluid and the alcohol from the chamber and reducing a pressure inside the chamber. The method further comprises performing a baking treatment by supplying an oxygen gas or an ozone gas to the chamber after the reduction of the pressure inside the chamber.

## Claims

### Claim 1

A supercritical drying method for a semiconductor substrate, comprising:
introducing the semiconductor substrate into a chamber, a surface of the semiconductor substrate being wet with alcohol;
substituting the alcohol on the semiconductor substrate with a supercritical fluid of carbon dioxide;
discharging the supercritical fluid and the alcohol from the chamber while reducing a pressure inside the chamber; and
performing a baking treatment in the treatment chamber while supplying an oxygen gas or an ozone gas to the chamber after the reduction of the pressure inside the chamber.

### Claim 2 (depends on 1)

The supercritical drying method for a semiconductor substrate according to claim 1, wherein the temperature inside the chamber is increased to a temperature equal to or more than the thermodecomposition temperature or the boiling point of an organic component contained in the carbon dioxide before performing the baking treatment.

### Claim 3 (depends on 1)

The supercritical drying method for a semiconductor substrate according to claim 1, further comprising:
cleaning the semiconductor substrate with a chemical liquid;
rinsing the semiconductor substrate with pure water after the cleaning of the semiconductor substrate with the chemical liquid; and
rinsing the semiconductor substrate with the alcohol after the rinsing of the semiconductor substrate with the pure water and before the introducing the semiconductor substrate into the chamber.

### Claim 4 (depends on 1)

The supercritical drying method for a semiconductor substrate according to claim 1, wherein
the semiconductor substrate has a metal film formed thereon; and
the temperature inside the chamber is maintained at 75° C. or more, and less than a critical temperature of the alcohol during the substituting the alcohol on the semiconductor substrate with the supercritical fluid and during the reducing the pressure inside the chamber.

### Claim 5 (depends on 4)

The supercritical drying method for a semiconductor substrate according to claim 4, wherein
the temperature inside the chamber is maintained at 97° C. or more during substituting the alcohol on the semiconductor substrate with the supercritical fluid and during the reducing the pressure inside the chamber.

### Claim 6 (depends on 4)

The supercritical drying method for a semiconductor substrate according to claim 4, wherein the metal film contains tungsten, titanium, or titanium nitride.

### Claim 7 (depends on 1)

The supercritical drying method for a semiconductor substrate according to claim 1, wherein the oxygen gas or the ozone gas is supplied to the chamber when the pressure inside the chamber is atmospheric pressure.

### Claim 8 (depends on 1)

The supercritical drying method for a semiconductor substrate according to claim 1, wherein the alcohol is isopropyl alcohol.