JP2001068447A - Wet washing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the surface of an object which is to be washed from being oxidized during washing by providing an ultra pure water supply line for supplying an ultra pure water to a washing bath and water channel with a film degassing element. SOLUTION: A diluted hydrofluoric acid bath 2, water channels 3, 5, and 7, an ammonium hydrogen peroxide water-solution bath 4, and a hydrochloric acid hydrogen peroxide water-solution bath 6 are provided in sequence, and an ultra pure-water line 1 supplies ultra pure-water to them. Here, a film degassing module 13 is provided before a stage where the ultra pure-water line 1 injects ultra pure-water into each bath. The film degassing module 13 provides the ultra pure-water line 1 which is to be processed to one chamber among those separated by a gas separating film permeable of gas while providing a trace amount of nitrogen gas to the other chamber on a secondary side during decompression, so that the gas contained in the ultra pure water line 1 is moved and removed to the other chamber through the gas separating film, for degassing. Generally, the hydrophobic polymer film to tetrafluoroethylene, and silicon rubber, etc., is formed into a hollow yarn film, etc., which is used as the gas separating film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet cleaning apparatus, and more particularly to a wet cleaning apparatus in which the amount of dissolved oxygen in ultrapure water is controlled.

[0002]

2. Description of the Related Art In a manufacturing process of a semiconductor device, a cleaning line using ultrapure water is used for cleaning a silicon wafer. However, conventionally, there has been a problem that a natural oxide film is formed on the surface of a silicon wafer due to the influence of oxygen dissolved in ultrapure water. The formation of a natural oxide film in this manner prevents the formation of an epitaxial silicon oxide film at a low temperature, hinders precise control of the thickness and film quality of a thin gate oxide film, and further reduces the fine cross-sectional area. An adverse effect such as an increase in the contact resistance of the contact hole occurs.

[0003] Therefore, the effects are particularly large in (1) a process for forming a capacitive insulating film, (2) a process for forming an electrode, (3) an epitaxial growth process, and (4) a process for forming a gate insulating film. In particular, in recent years, the influence of the natural oxide film on the wafer surface becomes particularly important as the miniaturization and the performance of the semiconductor device progress.

Conventionally, for ultrapure water used in the wet cleaning process, TOC (total organic oxygen) and fine particles in liquid have been mainly controlled, but the dissolved oxygen amount is particularly controlled. However, the concentration of oxygen dissolved in ultrapure water is close to the saturation state, which causes the formation of a natural oxide film.

Further, conventionally, the inside of a wet cleaning apparatus has been in a dry air (dry air) atmosphere which has been cleaned by a cleaning filter. There is a problem that a natural oxide film is formed on the surface of the wafer while the wafer is held on the wafer or while the wafer is being transported.

[0006]

As described above, in the conventional wet cleaning apparatus, sufficient consideration is not given to dissolved oxygen in ultrapure water and dry air in the apparatus. There is a problem that a natural oxide film is formed on the substrate. An object of the present invention is to solve this problem by a relatively simple method and to realize a wet cleaning apparatus in which the silicon wafer surface is not naturally oxidized.

[0007]

In order to achieve the above-mentioned object, the present invention provides a cleaning tank, a flowing water tank, and an ultrapure water supply line for supplying ultrapure water to each of these tanks. In a wet cleaning apparatus for cleaning electronic component materials using ultrapure water, a membrane degassing element is provided in the ultrapure water supply line. Thereby, the amount of dissolved oxygen in the ultrapure water can be reduced, and the surface of the object to be cleaned can be prevented from being oxidized during the cleaning.

In the wet cleaning apparatus, a cleaning filter using a dry gas is provided above the cleaning tank and the flowing water tank, and the dry gas used in the cleaning filter is a nitrogen gas. I do. Thus, the inside of the wet cleaning apparatus can be set to a nitrogen atmosphere, and the surface of the object to be cleaned can be prevented from being oxidized during transportation.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a wet cleaning apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

Before describing the present invention, a conventional wet cleaning apparatus will be described first for comparison. In FIG.
FIG. 1 is a schematic plan view showing a tank configuration of a conventional standard wet cleaning apparatus. In FIG. 3, reference numeral 1 denotes an ultrapure water line, reference numeral 2 denotes a diluted hydrofluoric acid (DHF) tank, reference numerals 3, 5, and 7 denote flowing water tanks, and reference numeral 4 denotes an aqueous ammonia hydrogen peroxide solution (A
Reference numeral 6 denotes a hydrochloric acid / hydrogen peroxide aqueous solution (HPM) tank.

In the tank configuration shown in FIG. 3, the silicon wafer is carried from the DHF tank 2 on the left side of the figure to the flowing water tank 7 on the right side, and without impairing the flatness of the silicon wafer surface at the atomic level, the silicon wafer surface is removed. Organic substances, fine particles, metals, natural oxide films, etc. attached to the surface can be removed. This tank configuration is an example, and is not necessarily limited to this configuration. With this configuration, ultrapure water is injected into each tank from the ultrapure water line 1. According to this conventional method, the dissolved oxygen in the ultrapure water is almost saturated, and a natural oxide film is formed on the silicon wafer surface. It is formed.

FIG. 4 is a front view of the conventional wet cleaning apparatus. In FIG. 4, reference numeral 8 denotes a cleaning filter,
Reference numeral 9 denotes a tank configuration, reference numeral 10 denotes a drying chamber, reference numeral 11 denotes an IN port portion, reference numeral 12 denotes an OUT port portion, an arrow 21 denotes an air flow, and an arrow 22 denotes a wafer transfer flow. I have. The tank configuration 9 in this front view is an arrangement of the tank configuration in FIG. 3 viewed from below in FIG.
Inside, a DHF tank 2, running water tanks 3, 5, 7, an APM tank 4, and an HPM tank 6 are arranged in the order shown in FIG. 3, and the ultrapure water line 1 supplies ultrapure water to them. I have. In this wet cleaning device, dried air (dry air) is used for the cleaning filter 8. For this reason, the apparatus is in a clean dry air atmosphere, and a natural oxide film is formed on the silicon wafer surface even during wafer transfer.

FIG. 1 is a schematic plan view showing a tank configuration of an embodiment of the wet cleaning apparatus of the present invention. In FIG. 1, reference numeral 1 denotes an ultrapure water line, and reference numeral 2 denotes a diluted hydrofluoric acid (DH).
F) tank, reference numeral 3, reference numeral 5, reference numeral 7 is a running water tank, reference numeral 4 is an ammonia hydrogen peroxide aqueous solution (APM) tank, reference numeral 6 is a hydrochloric acid hydrogen peroxide aqueous solution (HPM) tank, reference numeral 13 is a membrane deaeration module, Reference numeral 15 denotes a nitrogen gas line. In this figure, parts other than the tank configuration are omitted. In this figure, the same components are denoted by the same reference numerals for comparison with FIG.

This configuration differs from the configuration of the conventional wet cleaning apparatus of FIG. 3 in that the ultrapure water line 1 is provided with a membrane deaeration module 13 before injecting ultrapure water into each tank. This membrane degassing module 13 has a nitrogen gas line 15
To perform a physical deaeration by flowing nitrogen gas. Specifically, the membrane degassing module 13 allows the ultrapure water 1 to be treated to flow into one chamber partitioned by a gas-permeable gas separation membrane, and a small amount of nitrogen gas to flow into the other chamber on the secondary side. The pressure is reduced while flowing, and the gas contained in the ultrapure water to be treated 1 is moved to the other chamber via the gas separation membrane to be removed, and degassing is performed. In general, a gas separation membrane in which a hydrophobic polymer membrane such as a tetrafluoroethylene-based or silicone rubber-based membrane is formed into a hollow fiber membrane shape or the like is used.

As described above, by using the membrane degassing module 13, the ultrapure water dissolved in each of the cleaning tanks such as the DHF tank 2, the APM tank 4, the HPM tank 6, and the flowing water tanks 3, 5, and 7 is dissolved. By reducing the amount of oxygen, the formation of a natural oxide film on the wafer surface due to dissolved oxygen in ultrapure water can be prevented.

FIG. 2 shows a front view of the wet cleaning apparatus of the present embodiment. This front view corresponds to the arrangement of the conventional example in FIG. 2, reference numeral 8 denotes a cleaning filter, reference numeral 9 denotes a tank configuration, reference numeral 10 denotes a drying chamber, reference numeral 11 denotes an IN port portion, reference numeral 12 denotes an OUT port portion, and reference numeral 21
Arrows indicate the flow of nitrogen gas, and arrow 22 indicates the flow of wafer transfer. In tank configuration 9 in this front view,
The tank configuration shown in FIG. 1 is included.

The difference between the embodiment shown in FIG. 2 and the conventional one shown in FIG. 4 is that the embodiment shown in FIG.
Using nitrogen gas instead of air for the cleaning filter 8,
The difference is that doors for shutting off outside air are provided in the N port section 11 and the OUT port section 12. By doing so, the nitrogen gas can be rectified and circulated, and the inside of the apparatus becomes a nitrogen atmosphere, so that the wafer surface does not come into contact with air even during transfer, and the oxidation reaction is suppressed to the utmost. The growth of a natural oxide film on the surface of the wafer can be suppressed.
At the same time, it is possible to prevent an influence on the surrounding environment and a human influence due to the nitrogen gas flowing out of the apparatus.

As described above, according to the present invention, the ultrapure water line 1
By adding the film degassing module 13 to the substrate, the amount of dissolved oxygen in the ultrapure water can be reduced, and the growth of a natural oxide film on the surface of the silicon wafer can be suppressed. In addition, by setting the atmosphere in the wet cleaning apparatus to an inert gas atmosphere such as a nitrogen gas, the growth of a natural oxide film during transportation can be suppressed.

In the above description, an example in which the present invention is applied to cleaning of a silicon wafer of a semiconductor device has been described.
The present invention can be widely applied to a cleaning apparatus using a gas or a liquid as a carrier. The objects to be cleaned include semiconductor wafers such as silicon, substrates such as glass substrates for liquid crystals, completed and semi-finished products of electronic components such as memory devices, CPUs, and sensor devices, quartz reaction tubes, cleaning tanks, and substrates. A component for an electronic component manufacturing apparatus such as a carrier can be used.

[0020]

As described above, the first aspect of the present invention has a cleaning tank, a flowing water tank, and an ultrapure water supply line for supplying ultrapure water to each of these tanks. In a wet cleaning apparatus for cleaning electronic component materials using ultrapure water, a membrane degassing element is provided in an ultrapure water supply line. Thereby, the amount of dissolved oxygen in the ultrapure water can be reduced, and the surface of the object to be cleaned can be prevented from being oxidized during the cleaning.

According to a second aspect of the present invention, the cleaning tank is a dilute hydrofluoric acid (DHF) tank, and the ammonia hydrogen peroxide aqueous solution (A
PM) tank and aqueous hydrochloric acid / hydrogen peroxide solution (HPM) tank, and the flowing water tank is provided at a stage subsequent to these washing tanks. This makes it possible to efficiently remove organic substances, fine particles, metals, natural oxide films and the like adhering to the surface of the object to be cleaned.

The invention according to claim 3 of the present invention and the invention according to claim 5 of the present invention include a cleaning tank, a flowing water tank, and an ultrapure water supply line for supplying ultrapure water to each of these tanks. In a wet cleaning apparatus for cleaning electronic component materials such as silicon wafers using ultrapure water, a cleaning filter using a dry gas is provided above a cleaning tank and a flowing water tank, and the dry gas used in the cleaning filter is used. Is nitrogen gas. Thus, the inside of the wet cleaning apparatus can be set to a nitrogen atmosphere, and the surface of the object to be cleaned can be prevented from being oxidized during transportation.

The invention according to a fourth aspect of the present invention is characterized in that a door is provided in the input / output section of the wet cleaning device to shut off the inside of the wet cleaning device from the outside air. As a result, the inside of the wet cleaning apparatus can be made to have a nitrogen atmosphere, the surface of the object to be cleaned can be prevented from being oxidized during transportation, the nitrogen gas circulation can be made efficient, and the effect on the external environment can be reduced. Can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing a tank configuration of a wet cleaning apparatus of the present invention.

FIG. 2 is a front view of the wet cleaning apparatus according to the embodiment shown in FIG. 1;

FIG. 3 is a schematic plan view showing a tank configuration of a conventional wet cleaning apparatus.

FIG. 4 is a front view of a conventional wet cleaning apparatus.

[Explanation of symbols]

1. Ultrapure water line, 2. Dilute hydrofluoric acid (DHF) tank, 3,
5, 7: running water tank, 4: ammonia aqueous solution of hydrogen peroxide (A
PM) tank, 6 ... HCl aqueous solution of hydrogen peroxide (HPM), 8
... cleaning filter, 9 ... tank configuration, 10 ... drying room, 11 ...
IN port section, 12 OUT port section, 13 membrane degassing module, 15 nitrogen gas line, 21 flow of nitrogen gas or air, 22 flow of wafer transfer.

Claims (5)

[Claims] 1. A wet cleaning apparatus having a cleaning tank, a flowing water tank, and an ultrapure water supply line for supplying ultrapure water to each of these tanks, and for cleaning an electronic component material using ultrapure water. A wet cleaning apparatus, wherein a membrane degassing element is provided in the ultrapure water supply line. 2. The cleaning tank is a diluted hydrofluoric acid tank, an aqueous ammonia hydrogen peroxide tank and an aqueous hydrochloric acid hydrogen peroxide tank, and the flowing water tank is provided at a stage subsequent to each of these cleaning tanks. The wet cleaning apparatus according to claim 1, wherein 3. A wet cleaning apparatus having a cleaning tank, a flowing water tank, and an ultrapure water supply line for supplying ultrapure water to each of these tanks, and cleaning an electronic component material using ultrapure water. A wet cleaning apparatus, comprising a cleaning filter using a dry gas above the cleaning tank and the flowing water tank, wherein the dry gas used for the cleaning filter is nitrogen gas. 4. The wet cleaning apparatus according to claim 3, wherein a door is provided in an input / output section of the wet cleaning apparatus to shut off the inside of the wet cleaning apparatus from the outside air. 5. The apparatus according to claim 1, further comprising a cleaning filter using a dry gas above the cleaning tank and the flowing water tank, wherein the dry gas used in the cleaning filter is nitrogen gas. The wet cleaning device as described in the above.