JPH0513398A - Cleaning method for substrate - Google Patents

Abstract

PURPOSE:To make it possible to reduce the manufacturing cost of a device as there is no need to provide an organic contaminant cleaning process, to facilitate monitoring of the operation of the device and maintenance and management of the device and to make it possible to decompose many organic contaminants in a short time compared to a conventional cleaning of organic contaminants using ozone, which is performed at a temperature of about 20 to 30 deg.C. CONSTITUTION:A cleaning method of a substrate is characterized by that ozone is injected in clean steam obtained by a pure water manufacturing device 4 for multiple effect use to manufacture the mixed vapor of pure steam and the ozone, this mixed is made to jet through spray nozzles 16 in a vapor cleaning tank 1 to wash out contaminants adhered on the substrate 5 and at the same time, after filmy organic contaminants are made to decompose by the ozone, the substrate 5 is cleaned with high-purity water in a high-purity water cleaning tank 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning various substrates such as glass substrates for liquid crystals and semiconductor substrates which are particularly suitable for cleaning microfabricated substrates.

In this specification, "pure water vapor" means
It means water vapor generated by heating pure water or ultrapure water and clean water vapor such as water vapor obtained in the process of producing ultrapure water.

[0003]

2. Description of the Related Art Conventionally, as a method of cleaning a microfabricated substrate, Japanese Patent Laid-Open No. 1-189127 discloses that a substrate is exposed to steam generated by heating ultrapure water and then cleaned with ultrapure water. A substrate cleaning method is disclosed.

[0004]

In the above substrate cleaning method, water vapor easily penetrates into finer portions than water, and water vapor permeates into finely processed portions of the substrate to enhance surface wettability by ultrapure water. Although a high cleaning effect was obtained, a sufficient effect was not obtained for cleaning organic contaminants, particularly film-like organic contaminants adhering to the microfabricated portion.

Therefore, before carrying out this cleaning method,
Organic pollutants for oxidizing and decomposing organic pollutants, especially film-like organic pollutants adhering to the microfabrication part, by using ammonia hydrogen peroxide solution, which is a mixture of pure water with ammonia and hydrogen peroxide, or ozone. Since it is necessary to provide a cleaning process, the cleaning system is complicated, the manufacturing cost of the device is high, and operation monitoring and maintenance of the device are troublesome.

An object of the present invention is that it is not necessary to provide an organic pollutant cleaning step, so that the manufacturing cost of the device can be reduced,
In addition, the operation monitoring and maintenance of the device are easy, and more organic pollutants are decomposed in a shorter time than the conventional cleaning of organic pollutants by ozone performed at a temperature of about 20 to 30 ° C. It is to provide a substrate cleaning method capable of performing the above.

[0007]

A substrate cleaning method according to the present invention is characterized in that a mixed vapor of pure water vapor and ozone is sprayed from a spray nozzle for cleaning, and then cleaned with ultrapure water. ..

[0008]

When the mixed vapor of pure water vapor and ozone is jetted from the spray nozzle, the mixed vapor collides with the substrate, and the impact force at this time flushes away some of the contaminants adhering to the surface of the substrate, and partly removes the fine particles. Convert and disperse. Then, pure water vapor permeates into the microfabricated portion to enhance the surface wettability with ultrapure water in the subsequent step, and ozone oxidizes and decomposes the film-like organic contaminants adhering to the microfabricated portion for cleaning. The oxidative decomposition effect of ozone increases as the temperature increases, and pure water vapor heats the substrate to improve the oxidative decomposition effect of ozone on organic pollutants.

Then, when the substrate is washed with ultrapure water, pure water vapor permeates into the microfabricated portion to enhance the surface wettability. Therefore, the ultrapure water permeates into the microfabricated portion, and the inorganic contaminants remaining on the substrate. Rinse the substrate to make it extremely clean.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the substrate cleaning apparatus comprises a steam cleaning tank (1), an ultrapure water cleaning tank (2), and a drying chamber (3).
, Multi-effect pure water production system (4), and substrate to be cleaned (5)
And a conveyor (7) carrying a mount (6) to which is mounted.

The multiple-effect pure water producing apparatus (4) comprises a raw water pretreatment apparatus, a primary pure water-based multiple effect distillation apparatus and a secondary pure water-based multiple effect distillation apparatus. In the primary pure water system multi-effect distillation apparatus, primary pure water and primary pure water vapor are obtained from the raw water pretreated by the raw water pretreatment unit, and in the secondary pure water system multi-effect distillation apparatus, the primary pure water is Using the source pure water and the primary pure water vapor as heating steam, secondary pure water vapor that is as clean as ultrapure water is obtained, and the secondary pure water vapor is condensed to obtain secondary pure water,
That is, ultrapure water is obtained.

A part of the secondary pure water vapor obtained in the multi-effect pure water producing device (4) is taken out in a vapor state,
Sent by (8) and injected with more clean ozone,
It is used for substrate cleaning with a mixed vapor of pure water vapor and ozone in the vapor cleaning tank (1). The mixed vapor of pure water vapor and ozone is sent to the dispersion pipe (10) through the air supply pipe (8), and the substrate is supplied from a plurality of spray nozzles (16) provided in the dispersion pipe (10).
It is injected at (5).

The ultrapure water obtained by the multi-effect pure water producing apparatus (4) is sent to the ultrapure water cleaning tank (2) by the water supply pipe (9) and used for cleaning the substrate with ultrapure water. Ultrapure water pipes (9)
Through the dispersion pipe (11) and sprayed onto the substrate (5) from a plurality of spray nozzles (17) provided in the dispersion pipe (11).

In this embodiment, the temperature of pure water vapor is 105.
At ℃, ultrapure water has a specific resistance of 18.0 MΩ · cm and a temperature of 80 ℃.
The substrate cleaning space in the vapor cleaning tank (1) and the ultrapure water cleaning tank (2) is operated at atmospheric pressure.

The process of cleaning the semiconductor substrate (5) having the finely processed trench (5a) will be described below with reference to FIG.

The contaminant (A) is attached to the wall of the trench (5a) of the semiconductor substrate (5) (see FIG. 2a). Steam cleaning tank (1)
The mixed vapor of pure water vapor and ozone injected from the spray nozzle (16) of the dispersion pipe (10) inside the substrate (5) collides with the substrate (5), and the impact force at this time collides with the wall of the trench (5a). Part of the contaminant (A) adhering to is washed away, and part of the contaminant (A) is made into fine particles (B) and dispersed (see Fig. 2b). Then, the pure water vapor permeates into the trench (5a) of the substrate (5) to enhance the surface wettability by the ultrapure water in the subsequent step and to increase the temperature of the substrate (5) to 105
By raising the temperature to near 0 ° C., ozone oxidizes and decomposes the film-like organic contaminants adhering to the walls of the trench (5a) into carbon dioxide and water. As shown in FIG. 3, the higher the temperature, the faster the decomposition rate of organic substances by ozone, and therefore, the shorter the organic ozone pollutant cleaning is performed under the temperature of about 20 to 30 ° C., the shorter the time. Many organic pollutants can be decomposed.

Thus, at the end of the cleaning step with the mixed vapor, most of the contaminant (A) is removed, and even if it is attached, only the inorganic contaminant (C) is present, and it is in a state of being dispersed into fine particles. (See FIG. 2c).

Next, the substrate (5) cleaned in the cleaning process with mixed vapor is sent to the ultrapure water cleaning tank (2) by the conveyor (7) and cleaned with ultrapure water.

Since the wettability of the surface of the trench (5a) wall is enhanced by the permeation of pure water vapor in the cleaning process with the mixed vapor, the ultrapure water injected from the spray nozzle (17) of the dispersion pipe (11) is Easy to penetrate into the trench (5a), the trench (5a)
Contaminants (B) mainly composed of inorganic substances remaining in the
Clean (5). At this time, the ultrapure water in the trench (5a) receives the spray injection energy and is agitated in the trench (5a), and new ultrapure water is sequentially supplied into the trench (5a). ) Can be efficiently washed.

Then, the substrate washed with ultrapure water (5)
Is sent to the drying chamber (3) by the conveyor (7) and the drying chamber (3)
It is dried with cold air by the clean nitrogen gas flowing inside.

Most of the pure water vapor in the mixed vapor after cleaning the substrate (5) is condensed on the outer surface of the cooling pipe (12) through which cooling water flows inside the pipe provided above the cleaning tank (1), It flows down through the downflow pipe (13) to the bottom of the steam cleaning tank (1), and the steam cleaning tank (1)
It is returned to the multi-effect pure water producing apparatus (4) through the drain pipe (14) provided at the bottom of the tank and reused. On the other hand, uncondensed pure water vapor and ozone are passed through the vent pipe (15) to a steam cleaning tank.
(1) It is discharged to the outside.

[0023]

According to the substrate cleaning method of the present invention,
By spraying a mixed vapor of pure water vapor and ozone from a spray nozzle, some of the contaminants adhering to the surface of the substrate are washed away, some of them are made into fine particles and dispersed, and pure water vapor permeates the microfabricated part. Since the surface wettability by the ultrapure water in the process is enhanced and the film-like organic contaminants adhered to the finely processed portion are oxidatively decomposed and cleaned by ozone, it is not necessary to provide an organic contaminant cleaning process. Therefore, the manufacturing cost of the device can be reduced, and operation monitoring and maintenance of the device can be facilitated.

Moreover, since pure water vapor heats the substrate to improve the oxidative decomposition effect of the organic pollutants by ozone, compared with the conventional cleaning of organic pollutants by ozone performed at a temperature of about 20 to 30 ° C. Therefore, many organic pollutants can be decomposed in a short time.

[Brief description of drawings]

1 is a schematic vertical cross-section of an apparatus embodying the present invention.

2A to 2C are cross-sectional views sequentially showing a process of cleaning with a mixed vapor of pure water vapor and ozone.

FIG. 3 is a graph showing the relationship between the decomposition rate of organic pollutants by ozone and temperature.

[Explanation of symbols]

 (1) Steam cleaning tank (2) Ultra pure water cleaning tank (4) Multi-effect pure water production system (5) Substrate (8) Air pipe (9) Water pipe (10) (11) Dispersion pipe (16) (17) ) spray nozzle

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shiro Inoue 5-3-28 Nishi-Konojo, Konohana-ku, Osaka City Hitachi Shipbuilding Co., Ltd. Inside Hitachi Shipbuilding Co., Ltd. (72) Inventor Hideo Suematsu 5-3-2, Nishikujo 5-chome, Konohana-ku, Osaka City Inside Hitachi Shipbuilding Co., Ltd.

Claims (1)

Claim: What is claimed is: 1. A method of cleaning a substrate, which comprises spraying a mixed vapor of pure water vapor and ozone from a spray nozzle for cleaning, and then cleaning with ultrapure water.