JP2000021834A - Rapid jet ultrapure water washing method and its apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rapid jet ultrapure washing method and its apparatus which can effectively prevent the effects of static electricity without requiring special installation and improvement, can be realized at a low cost, and can maintain characteristics such as specified fused remaining oxygen concentration in ultra pure water. SOLUTION: (1) In an ultrapure water washing method for washing a wafer 3 by rapid jet washing water of ultrapure water, rapid jet water flow 1 of ultrapure water and a curtain flow 2 of ultrapure water with uniform and controlled film thickness which encloses the water flow of rapid jet washing water of ultrapure water therein are jetted onto a wafer to be washed for washing. (2) In the ultrapure water washing device, the rapid jet water flow 1 is formed of a spray nozzle 5 and an orifice 6, and the curtain flow 2 is formed of an orifice nozzle 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-speed jet ultrapure water cleaning method and apparatus, and more particularly to a high-speed jet ultrapure water cleaning method for cleaning various wafers used in manufacturing semiconductor data and the like. The present invention relates to a cleaning apparatus using a method.

[0002]

2. Description of the Related Art Conventionally, various kinds of wafers used in manufacturing semiconductor devices and the like have been washed with high-speed jet ultrapure water. The purpose of such cleaning is to remove fine particles on the wafer.

[0003] As a conventional high-speed jet ultrapure water cleaning method, a scrubber cleaning method in which a high-speed jet water stream is sprayed onto a surface to be cleaned of a wafer is known. There is a device described in a gazette or the like.

However, when the ultrapure water is generated as a high-speed jet stream, static electricity is generated in the ultrapure water by spray charging, which is generally called the Leonard effect. It is said that this is because a charged layer of negative ions is formed on the surface of the high-speed jet water flow in contact with the atmosphere.

[0005] The static electricity generated by the high-speed jet water flow is
If it accumulates on the wafer, particles in the ultrapure water and particles separated from the wafer surface by the jet water flow may be attracted and adhered. In addition to this, for example, dielectric breakdown of the gate oxide film of a submicron device / It has been pointed out that a problem such as fusing of the polysilicon wiring may occur.

On the other hand, in recent years, a causal relationship between residual oxygen in ultrapure water and a natural oxide film on a silicon wafer has become clear, and control of residual oxygen in ultrapure water has become more important. Under such circumstances, it is essential to maintain and supply ultrapure water in which the residual oxygen concentration is strictly controlled.

In the prior art, in order to prevent the generation of static electricity in ultrapure water, it is exposed to an ionized gas (Japanese Patent Laid-Open No.
JP-A-5-162379), injecting positively charged ions simultaneously with the injection of ultrapure water (JP-A-7-66163), or adding CO ₂ gas to ultrapure water to lower the resistance (JP-A-Hei. No. 7-45569), ultrapure water is charged positively through a pipe made of a specific material (JP-A-4-3424), and is washed and dried in an ionic atmosphere (JP-A-3-3549).
No. 131026) has been proposed. However, all of these require special equipment and devices other than the injection device (nozzle, etc.) for forming a water flow which is originally required. In addition, there is no effect on control of residual oxygen in ultrapure water (prevention of dissolution of oxygen).

[0008]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to effectively prevent the influence of static electricity and to make it special. A high-speed jet ultrapure water cleaning method and apparatus that can be easily and inexpensively realized without the need for equipment and contrivance, and can easily maintain characteristics such as a predetermined residual oxygen concentration in ultrapure water. The purpose is to provide.

[0009]

A high-speed jet ultrapure water cleaning method according to the present invention is directed to an ultrapure water cleaning method for cleaning a wafer with ultrapure water high-speed jet cleaning water. And a curtain flow of ultrapure water surrounding the high-speed jet cleaning water of the ultrapure water and jetting the same to the wafer to be cleaned for cleaning.

A high-speed jet ultrapure water cleaning apparatus according to the present invention is an ultrapure water cleaning apparatus for cleaning a wafer with ultrapure water high-speed jet cleaning water. And a water flow forming section for providing a curtain flow of ultrapure water surrounding the high-speed jet cleaning water, and a high-speed jet cleaning water flow of the ultrapure water flowing through the central portion, and an ultrapure surrounding the high-speed jet cleaning water. The cleaning is performed by spraying a curtain flow of water onto a wafer to be cleaned.

According to the present invention, the high-speed jet cleaning water flow of the ultrapure water is surrounded by a curtain flow of the ultrapure water (preferably a curtain flow having a uniform and controlled film thickness). By being surrounded, it is isolated from the atmosphere. Thus, the surrounding high velocity jet stream surface is not in contact with the atmosphere. Therefore, the water flow surface is not charged by contact with the atmosphere, and the generation of static electricity is prevented.
In addition, because the high-speed jet cleaning water flow of ultrapure water does not come into contact with the atmosphere, it is cut off from the gas in the atmosphere, preventing undesired gas contamination, and the high-purity high-speed jet cleaning water flow originally has The predetermined cleaning can be performed without deteriorating while maintaining the characteristics of the ultrapure water, and particularly while maintaining the predetermined residual oxygen concentration.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention will be described below, and the present invention will be further described by describing specific embodiments with reference to the drawings. However, it goes without saying that the present invention is not limited to the embodiment described and illustrated below.

In the present invention, when the wafer is cleaned with the high-speed jet cleaning water of the ultrapure water, the flow of the high-speed jet cleaning water of the ultrapure water and the flow of the high-speed jet cleaning water of the ultrapure water are interposed. The curtain flow of ultrapure water is sprayed onto the wafer to be cleaned to remove the particles on the wafer to be cleaned, and the curtain flow of ultrapure water is changed to the flow of the high-speed jet cleaning water inside. It functions to shut off the air. This prevents generation of static electricity in the flow of the high-speed jet cleaning water. In addition, the high-speed jet cleaning water is prevented from being contaminated by gas in the atmosphere.

In the practice of the present invention, the high-speed jet cleaning water flow of ultrapure water and the ultrapure water surrounding the high-speed jet cleaning water flow, preferably uniform and In order to form two ultrapure water flows with a curtain flow having a controlled film thickness, the following can be performed.
That is, a spray nozzle that generates an ultrapure water high-speed jet cleaning water flow flowing in the center, high-pressure pure water supply means that controls the jet water flow speed generated by the spray nozzle, and a curtain that generates a curtain flow of pure water It can be configured to include a flow generating means and a low-pressure pure water supply means for controlling the curtain flow generation of the pure water. In this case, the spray nozzle and a curtain flow generating means for generating a curtain flow of pure water can be configured by a body.

In practicing the present invention, it is desirable that the spray nozzle for generating the high-speed jet cleaning water flow has high pressure resistance so as to realize speed control in a wide range. In addition, since it is considered that the greater the separation of droplets, the greater the generation of static electricity, it is desirable to use a nozzle that can realize a water flow that does not generate droplets as much as possible, or that can increase the distance until droplets are generated.

As the high-pressure pure water supply means, a high-pressure clean pump suitable for wafer cleaning, which generates a small amount of particles and can realize predetermined pressure control can be preferably used.

There are several possible curtain flow generating means for generating a curtain flow of pure water.
An orifice nozzle that can achieve the required diameter, shape, and thickness of the curtain by changing the shape and size can be preferably used. In addition, any means can be adopted as long as it can obtain the necessary diameter, shape, and film thickness of the curtain.

The low-pressure pure water supply means for controlling the generation of the curtain flow of the pure water is similar to the high-pressure pure water supply means. A low-pressure clean pump can be preferably used.

The ultrapure water that can be used in the practice of the present invention is arbitrary, and removes the electrolyte up to a specific resistance of about 18 MΩ · cm, which is close to generally called theoretical pure water. It is preferable to use one having the above-mentioned characteristics removed as much as possible, and it is also possible to use one having a specific resistance smaller than the above, and it can be used as long as it can perform predetermined cleaning on the wafer to be cleaned.

Embodiment 1 In this embodiment, the present invention is applied to a semiconductor device manufacturing wafer, in particular, a semiconductor wafer (such as a silicon wafer).
This is mainly applied to the cleaning of the surface (element formation surface) for removing fine particles.

Referring to FIG. In the present example, the pure water cleaning water flow is divided into a high-speed jet cleaning water flow 1 of ultra-pure water flowing through the central portion and an ultra-pure water surrounding the high-speed jet cleaning water flow 1 as shown in FIG. In addition, there are two water flows, the curtain flow 2 having a controlled film thickness. The high-speed jet water flow 1 and the curtain flow 2 are applied to the wafer 3 to be cleaned to clean the wafer surface.

In the present embodiment, the high-speed jet water stream 1 and the curtain stream 2 are formed by a two-fluid forming nozzle indicated by reference numeral 4 in the figure. The two-fluid forming nozzle 4 has a spray nozzle 5 for forming a high-speed jet cleaning water flow and an orifice 6 for controlling a water flow therefrom, and
It has an orifice nozzle 7 which is a curtain flow generating means for generating a curtain flow of pure water. These are connected by a body 15.

Ultrapure water controlled to a predetermined purity is supplied from a pure water supply line 8 to a high-pressure clean pump 9. The purity of the ultrapure water in this case is a purity that satisfies the pure water quality required for cleaning a so-called submicron device.

The high-pressure clean pump 9 is provided so as to provide a flow velocity capable of realizing the high-speed jet water flow 1 necessary for removing fine particles from the semiconductor wafer 3 to be cleaned.
To control. The high-pressure ultrapure water controlled by the high-pressure clean pump 9 is supplied to the spray nozzle 5 through a pure water supply line 10. The spray nozzle 5 has an orifice 6 for converting the supplied high-pressure water into a water stream that generates as little droplets as possible, that is, a so-called flat high-speed jet water stream.
Is incorporated. The high-speed jet water stream 1 is formed by the spray nozzle 5 having the orifice 6.

A pure water curtain stream 2 surrounding the high-speed jet stream 1 is formed by an orifice nozzle 7. The high-speed jet water flow 1 flowing in the center portion and the pure water curtain flow 2 surrounding the high-speed jet water flow 1 are sprayed onto a surface to be cleaned of a semiconductor wafer 3 to be cleaned.

The diameter of the curtain stream 2 of pure water is desirably as close as possible to the outer diameter of the high-speed jet stream 1 flowing through the center. For this reason, the orifice shape of the orifice nozzle 7 forming the curtain flow 2 is preferably determined strictly by fluid analysis / simulation using fluid dynamics. Ultrapure water is supplied to the orifice nozzle 7 from a pure water supply line 11 by a low pressure clean pump 11 if necessary, and is supplied through a pure water supply line 13. In the figure, reference numeral 14
Is a seal for preventing water leakage between the two-fluid forming nozzle 4 and the spray nozzle 5 for forming the high-speed jet cleaning water flow, and usually uses an O-ring.

In this example, the cleaning is specifically performed by the cleaning device having the above-described configuration as follows. High-speed jet water flow 1
Is supplied under pressure by a high-pressure clean pump 9 and the nozzle 5
The orifice 6 is formed by being converted into a high-speed jet water flow, which is sprayed onto the semiconductor wafer 3 to be cleaned to remove fine particles on the wafer 3.

At this time, assuming that the pressure of the high-pressure clean pump 9 is 9.8 MPa and the diameter of the orifice 6 is 100 μm, the speed of the high-speed jet water stream 1 is about 130 m / s. The high-speed jet water stream 1 is sprayed onto the fine particles on the wafer 3 at an angle of about 45 °, and the fine particles are removed by the impact force generated at that time.

A curtain stream 2 is formed by an orifice nozzle 7 so as to surround the high-speed jet stream 1. In the present embodiment, the high-speed jet water flow 1 is covered by the curtain flow 2. Therefore, the high-speed jet water stream 1 does not come into contact with the atmosphere. As a result, the generation of the spray charge called the Leonard effect is prevented. Therefore, the amount of static electricity accumulated on the semiconductor wafer 3 to be cleaned is very small, and the influence of static electricity, for example, element destruction due to static electricity can be prevented. In addition, this high-speed jet water flow 1
Since it does not come into contact with the atmosphere, pollution by static electricity generated in the atmosphere is prevented. At the same time, the effects of atmospheric gases are prevented, and in particular, the diffusion of atmospheric oxygen into the high-speed jet water stream 1 is prevented. Therefore, the characteristics inherent in the high-speed jet water stream 1, particularly the concentration of residual oxygen in the ultrapure water, are maintained, and the cleaning effect can be enhanced. Although the curtain flow 2 surrounding the high-speed jet water flow 1 may itself be contaminated by static electricity and oxygen in the atmosphere, the curtain flow 2 is high-speed There is no problem because it flows through the surface layer of the water stream 1 and does not directly contact the wafer 3 itself.

As described above, according to the present embodiment, the curtain flow 2 having a uniform thickness and a controlled thickness is formed around the high-speed jet water flow 1 of the ultrapure water. The high-speed jet water flow 1 is cut off from the atmosphere, does not generate an electric charge, prevents generation of static electricity, and prevents device destruction or the like due to static electricity. In addition, because it does not come into contact with the atmosphere, it is cut off from the gas in the atmosphere, and high efficiency maintaining the characteristics of high-purity ultrapure water (particularly, a predetermined residual oxygen concentration) originally provided by the high-speed jet cleaning water flow. Cleaning can be realized. Moreover, the configuration of this example is an improvement of the originally required components,
It can be realized simply by adding it to the conventional high-speed jet cleaning unit, and can be configured at low cost.

[0031]

As described above, according to the present invention, the effect of static electricity can be effectively prevented, and this can be realized easily, inexpensively and without any special equipment or device. A high-speed jet ultrapure water cleaning method and apparatus capable of maintaining characteristics such as a predetermined residual oxygen concentration in ultrapure water were provided.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a high-speed jet ultrapure water cleaning apparatus according to a first embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... High-speed jet water flow of ultrapure water, 2 ... Curtain flow of ultrapure water, 3 ... Wafer to be cleaned, 4 ... Nozzle forming nozzle, 5 ... Spray for forming high-speed jet water flow Nozzle, 6 ... orifice for forming high-speed jet water flow,
7 ... Orifice nozzle for curtain flow formation.

Claims (4)

[Claims] An ultrapure water cleaning method for cleaning a wafer with ultrapure water high-speed jet cleaning water, wherein the flow of ultrapure water high-speed jet cleaning water and the flow of ultrapure water high-speed jet cleaning water are interposed. A high-speed jet ultrapure water cleaning method, characterized by jetting a curtain flow of ultrapure water surrounding the wafer to a wafer to be cleaned to perform cleaning. 2. The high-speed jet ultrapure water cleaning method according to claim 1, wherein the curtain flow of the ultrapure water is a curtain flow having a uniform and controlled film thickness. 3. An ultrapure water cleaning apparatus for cleaning a wafer with ultrapure water high-speed jet cleaning water, comprising:
A water flow forming section for providing a curtain flow of ultrapure water surrounding the high-speed jet cleaning water, a high-speed jet cleaning water flow of the ultrapure water flowing through the central portion, and an ultrapure water surrounding the high-speed jet cleaning water. A high-speed jet ultrapure water cleaning apparatus characterized in that a curtain flow is sprayed onto a wafer to be cleaned to perform cleaning. 4. The high-speed jet ultrapure water cleaning apparatus according to claim 3, wherein the curtain flow of the ultrapure water is a curtain flow with a uniform and controlled film thickness.