JPS60143884A - Washing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (1) Technical Field of the Invention The present invention relates to the cleaning of samples such as glass substrates, bottom masks, wafers, etc. In particular, the H202-based cleaning solution for cleaning the samples is irradiated with far ultraviolet rays. Regarding cleaning methods.

(2) Background of the Technology In recent years, as semiconductor devices have become more expensive to build, even higher precision manufacturing is required in each manufacturing process of semiconductor devices.

One of the important steps in the manufacturing process is the sample cleaning process1.
Various methods have been used.

Among these various cleaning methods, there is a method in which a sample is immersed in a solution that generates active oxygen to decompose and remove organic dust adhering to the surface of the sample. However, in the above-mentioned method, active oxygen is no longer generated after a predetermined period of time, so that the sample cannot be effectively cleaned.

(3) - Prior Art and Problems Conventionally, one of the methods for cleaning the surface of a sample is an apparatus shown in FIG. 1 in which a sample 2 is immersed in a cleaning liquid 1. 1st
In the figure, a cleaning liquid 1, for example, peroxide water 1 (H
2O2) by adding ammonia (NHaOH) to H2O2
A sample 2 to be cleaned is immersed in the system solution. By adding ammonia to the hydrogen peroxide and further heating it to a constant temperature of, for example, 50° C., atomic oxygen (0), which is active oxygen, is generated. The active oxygen undergoes an oxidation reaction with organic dust adhering to the surface of the sample 2, decomposing and removing this organic dust. In addition, as a cleaning solution, hydrogen peroxide (H2O2) and sulfuric acid (82804), hydrogen peroxide (H2O2) and hydrochloric acid (HC
A H2O2-based solution containing I) may also be used.

- However, the cleaning solution is hydrogen peroxide (H202), sulfuric acid (H2SO4), ammonia (NHaOH), hydrochloric acid (
Hcl) is added to generate atomic oxygen (0), which is active oxygen, through a chemical reaction.

This atomic oxygen (0) undergoes an oxidation reaction and returns to oxygen (02), resulting in a problem in which the cleaning effect is lost.

(4) Purpose of the invention In view of the above-mentioned conventional problems, the present invention involves irradiating a cleaning solution of H2O2 solution with far ultraviolet rays and re-decomposing oxygen (02) produced by reacting with organic dust etc. on the sample surface. In addition to converting it into active oxygen, the energy of active oxygen is increased,
The purpose is to provide a cleaning method that contributes to cleaning the sample surface.

(5) Structure of the invention and this purpose is to prepare a sample according to the invention) I 202
This is achieved by providing a cleaning method characterized by immersing in a H2O2-based cleaning solution and performing cleaning while irradiating the H2O2-based cleaning solution with far ultraviolet rays.

(6) Examples of the invention Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 2 is a schematic diagram illustrating a cleaning method according to an embodiment of the present invention. Note that the same parts as in FIG. 1 are given the same reference numerals and redundant explanation will be omitted.

In FIG. 2, a deep ultraviolet light source 4 is provided on the peripheral side of a container 3 containing a +H2O2-based cleaning solution 1. A sample 2 such as a glass substrate, a photomask, or a wafer is then cleaned by immersing it in the cleaning liquid 1. Although not shown, a device for heating the cleaning liquid 1 and keeping it at a constant temperature is provided, for example, on the peripheral side of the container 3.

Cleaning solution 1 contains hydrogen peroxide (H2O2) and sulfuric acid (H2SOa).
) or ammonia (NHaOH), hydrochloric acid (HCI)
is added, heated, and kept at a constant temperature of, for example, 50°C. The cleaning liquid 1 undergoes a chemical reaction to form active oxygen, atomic oxygen (
0) is generated. The sample 2 immersed in the cleaning liquid 1 is cleaned by decomposing and removing organic dust adhering to the surface through an oxidation reaction with active oxygen. At this time.

The far ultraviolet rays emitted from the far ultraviolet light source 4 provided on the peripheral side of the container 3 promote decomposition and removal of organic dust attached to the surface of the sample 2 by active oxygen, and also cause an oxidation reaction. It works to convert active oxygen that has become 02 gas back into active oxygen. Therefore, if far ultraviolet rays are not irradiated, the cleaning solution 1 will not generate active oxygen when it is oxidized by a chemical reaction.

The cleaning effect of sample 2 is lost. However, as mentioned above, in addition to obtaining active oxygen through chemical reactions, this active oxygen becomes high energy by irradiation with far ultraviolet rays, and active oxygen is obtained by re-decomposing the 02 gas and turning it into ozone, so it adheres to sample 2. The decomposition and removal of organic dust, etc., is carried out quickly. That is, the cleaning liquid 1 can be used for a long time.

Effective cleaning can be performed. In addition, the short wavelength light 1B, 4.9 nm, 253°7 nm, etc. emitted from the far ultraviolet light source 4 directly cuts the chains of organic polymers etc. attached to the surface of the sample 2, converts them into lower molecules, and decomposes them. We are promoting removal. On the other hand, even if pure water is used as the cleaning solution 1 or an organic solvent (alcohol, ketones, etc.) is used as another aqueous solution, if far ultraviolet rays are irradiated, immersion in this cleaning solution 1 will have the same effect as described above. The organic polymer adhering to the sample surface can be reduced in molecular weight.

(7) Effects of the Invention As explained in detail above, the cleaning method of the present invention can increase the energy of active oxygen, and
This is because the active oxygen generated in the chemical reaction of the OR system solution can re-decompose the oxygen (O2) returned to its original state through oxidation reactions, etc., and turn it into active oxygen.

It has a great effect in effectively and efficiently cleaning samples such as glass substrates, photomasks, and wafers.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram illustrating a conventional sample cleaning method, and FIG. 2 is a schematic diagram illustrating an embodiment of the present invention. 1...Cleaning liquid, 2...Sample.

Claims (1)

[Claims] (1) Immerse the sample in H202-based cleaning solution, and
A cleaning method characterized by performing cleaning while irradiating an O2-based cleaning solution with far ultraviolet rays.