JPH11218236A - Fluid treating method and fluid treating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a valve change-over type fluid treating method and fluid treating device which have no influence due to the residual fluid in a preliminary treating. SOLUTION: When the diameter of an opening 2a is made R, and the length is made d, in a system to treat the fluid by an opening 2a, and a valve furnishing a rod form valve disc 3a, the condition R<=20 mm, and d<=(R/2) is made satisfied, and the amount of a liquid remaining at a step part which is formed by the above opening 2a is suppressed to the minimum amount.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for supplying a high-purity fluid required for a thin-film device manufacturing process, particularly for a semiconductor manufacturing process in which control of impurities is required.

[0002]

2. Description of the Related Art As a method for cleaning a substrate sample represented by a semiconductor substrate, for example, Japanese Patent Application Laid-Open No. 4-287922 proposes a spin-on-wafer method in which a substrate is processed while being rotated one by one. In a general spin-on-wafer method, the processing fluid needs to be supplied to the center of rotation of the substrate. However, according to the technique described in the above publication, an injection nozzle for the processing fluid can be provided separately from the substrate sample, Therefore, by using a plurality of nozzles, processing using a plurality of fluids becomes possible.

On the other hand, in addition to the method described in the above-mentioned publication, a method of spraying a processing fluid such as a cleaning liquid or an inert gas used for drying onto a surface of a substrate placed in a processing chamber atmosphere is disclosed in, for example, Japanese Patent Laid-Open Publication JP-A-61-42918, JP-A-60-7
4438, JP-A-8-78368, JP-A-8-13
No. 0202 and Japanese Patent Application Laid-Open No. 9-7939 propose a method in which a sample is made to face a predetermined processing member surface, and processing is performed while a processing fluid is flowing between the samples (hereinafter, referred to as conventional technology). ing.

[0004] In the case of this prior art, it is difficult to provide a plurality of nozzles because the nozzle for ejecting the processing fluid is close to the substrate. Commonly, a valve was provided in the fluid pipe leading to the nozzle, and the fluid supplied to the nozzle was switched.

[0005]

The prior art described above has a problem that no consideration is given to the residual of the fluid accompanying the use of the fluid switching valve, and the influence of the fluid used in the pretreatment cannot be suppressed. . That is, in the prior art,
Since the fluid supplied to the nozzle is switched, the fluid used in the pretreatment remains in the pipe.

For this reason, for example, as a pretreatment, after washing with a liquid and rinsing, when the fluid is changed to gas and dried as the next treatment, if the liquid remains in the piping, This causes a problem that drying of the sample is hindered.

As is well known, if a silicon substrate is not sufficiently dried, a dry stain called a watermark remains. This drying stain is caused by the contact of silicon with oxygen and water, and it is reported that this is due to a mechanism in which oxidized silicon dissolves in water and precipitates as a residue after drying. .

Accordingly, in order to suppress the generation of the watermark, it is necessary to prevent oxygen and water from coming into contact with the silicon substrate, and it is necessary to use a gas containing as little oxygen and water as possible during drying. There is. However,
In the related art, even if a gas containing neither oxygen nor water is used, there is a possibility that a fluid may be mixed in the pretreatment, so that it is difficult to suppress generation of a watermark.

It is an object of the present invention to provide a valve switching type fluid processing method and a fluid processing apparatus which are not affected by residual fluid in pretreatment.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a valve in which a fluid passage is opened and closed by pressing and pulling a valve body against an opening of a valve seat, and the diameter of the opening of the valve seat is reduced. R, and the length of the fluid passage connected to the opening of the valve seat is d.
This is achieved by satisfying the condition of d ≦ (R / 2).

If there is a valve in the fluid passage, a step is formed in the valve seat. On the other hand, if the fluid is a liquid,
Residue tends to occur at the step portion of the flow path. At this time, the diameter of the opening of the valve seat is R, and the length is d.
, Where R ≦ 20 mm and d
If the condition of ≤ (R / 2) is satisfied, it is possible to prevent the problem due to the remaining of the liquid from occurring, and thus the object is achieved.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. FIG. 1 shows an embodiment of a valve 20 used in the fluid treatment method and the fluid treatment device according to the present invention. In this figure, FIG. 1 (a) is a side sectional view, and FIG. FIG. 1A is a cross-sectional view taken along the line AA ′ of FIG. 1 (a), and as is apparent from these figures, the present invention has two inlet-side fluid passages and one outlet-side fluid passage. This is an embodiment applied to a double valve composed of two valves that are commonly used.

In these figures, 1 is a valve body,
2a and 2b are openings, 3a and 3b are valve bodies, 4a and 4b are inlet-side fluid passages, 5a and 5b are valve chambers, 6 is an outlet-side fluid passage, 7a and 7b are diaphragms, and 8 is a fluid outlet. Here, the subscript a is a component of one of the valves, and b
Indicates a component of the other valve.

The valve body 1 constitutes the main body of the valve 20, in which two openings 2a, 2b are formed as shown. And these openings 2a, 2b are
One end respectively faces each valve chamber 5a, 5b, and the other end communicates with a common outlet side fluid passage 6. Also,
Here, each of the valve chambers 5a and 5b is
a, 4b.

In the valve chambers 5a and 5b, rod-shaped valve bodies 3a and 3b are supported by flexible diaphragms 7a and 7b, respectively. And these valve bodies 3a, 3b
Is configured to be able to be moved left and right by a drive mechanism (not shown) as indicated by an arrow X. Note that a valve having such an opening and a rod-shaped valve body is generally called a needle valve. At this time, the member having the openings 2a and 2b is formed as a valve seat (valve seat).
The rod-shaped valve bodies 3a and 3b are called needle valves (needle valves).

Accordingly, the valve bodies 3a and 3b are not connected to the openings 2a and 2b.
b, the passage from the respective inlet-side fluid passages 4a, 4b to the outlet-side fluid passage 6 is closed when pressed against the end face, and the passage is opened when separated from the end face. Function is obtained. As a result, the valve 20 of FIG. 1 can be used as a switching valve for selecting a passage from the two inlet-side fluid passages 4a and 4b to the common outlet-side fluid passage 6.

In this valve 20, the fluid supplied from the inlet side fluid passages 4a, 4b to the valve chambers 5a, 5b respectively enters the outlet side fluid passage 6 via the openings 2a, 2b, and the fluid outlet It is led to 8. Here, the portions forming the openings 2a and 2b of the valve body 1, that is, the valve seats, need to have a certain strength, so that a certain thickness is required.

As a result, these openings 2a, 2a
b, as shown, has a length d, is inevitable that the step of volume V _D occurs in this portion. This step becomes a so-called dead volume, and when a liquid fluid flows, a liquid remains therein. For example, opening 2
The diameter of a and 2b is R, which is 4 mm and the length d is 2
mm, a maximum of 25 μL (L = liter) of the liquid remains.

Then, when such a liquid remains, when another fluid is caused to flow thereafter, that fluid is
The remaining fluid is mixed, which causes a problem as described above. Therefore, in this embodiment, the diameter R and the length d of the openings 2a and 2b satisfy the conditions of R ≦ 20 mm and d ≦ (R / 2). As a result, the openings 2a and 2b
The liquid remaining on the step is efficiently removed by the gas flow supplied later, and the above-mentioned problem can be solved.

Hereinafter, characteristics of the valve 20 according to the embodiment of the present invention will be described based on experimental results.

(Experimental Example 1) The valve 20 shown in FIG.
, The following three types of valves were prepared as comparative examples.

Valve I R = 4.0 mm, d = 4.0 mm Valve II R = 4.0 mm, d = 2.0 mm Valve III R = 4.0 mm, d = 2.0 mm Here, only the valve I is: The constituent features as the embodiment of the present invention described above, that is, R ≦ 20 mm, d ≦ (R /
It can be seen that the constituent requirement 2) is not satisfied, and only the remaining valves II and III satisfy the constituent requirements as the embodiment of the present invention.

Next, by using these valves I to III, first, as the liquid from the inlet side fluid passage 2b, 1.
After flowing ultrapure water at a flow rate of 0 L / min for 1 minute, dry nitrogen flows as a gas at a flow rate of 60 L / min from the inlet-side fluid passage 2 a, and after flowing out of the gas, flows out of the fluid outlet 8. The humidity in the incoming gas was measured.

FIG. 2 shows the measurement results.

As is apparent from FIG. 2, the valves II and III according to the embodiment of the present invention can reduce the humidity in a short time and obtain a gas free of water. On the other hand, in the case of the valve I that does not satisfy the constituent requirements as the embodiment of the present invention, it can be seen that the mixing of water does not easily stop.

Therefore, by using the valve 20 shown in FIG. 1, it is possible to easily obtain a valve switching type fluid processing method and a fluid processing apparatus which are not affected by the residual fluid in the pretreatment. In this case, the generation of a watermark or the like can be reliably suppressed. .

Although FIG. 1 shows an embodiment in which the present invention is applied to a double valve capable of switching between two types of fluids, the embodiment of the present invention is as shown in FIG. Alternatively, the valve 30 may be configured as a triple valve 30 including three valves, and the use of the valve 30 can be applied to a fluid process for switching three types of fluids.

In the embodiment of FIG. 3, the suffix “c” indicates the constituent elements of the third valve, and the other parts are the same as those of the embodiment of FIG. 1. At this time, the constituent elements of the embodiment of the present invention That is, it is needless to say that the components satisfy R ≦ 20 mm and d ≦ (R / 2).

Next, FIG. 4 shows a valve 40 according to still another embodiment of the present invention.
1 is the same as the embodiment of FIG. 1 except that two valves are arranged so as to face each other. Here, FIG. (a) is a cross-sectional view taken along the line AA ′, where, for example, the components of the valve on the left side of the figure are denoted by a suffix a, and the left side is denoted by a suffix b. And other configurations are
It is the same as the embodiment of FIG.

The feature of the embodiment shown in FIG. 4 is that the inlet-side fluid passages 2a and 2b of the respective valves face each other as shown in the drawing. It is desirable that the inner diameters of the side fluid passages 2a and 2b are equal and their central axes coincide.

As a result, in the valve according to the embodiment shown in FIG. 4, for example, the liquid remaining in the step of the inlet-side fluid passage 2a is efficiently converted in a short time by the airflow flowing from the opposed inlet-side fluid passage 2b. Thus, according to the embodiment, after the fluid is switched from the liquid to the gas, the mixing of the liquid remaining on the step with the gas can be further effectively suppressed.

Next, FIG. 5 shows a valve 50 according to still another embodiment of the present invention. In the embodiment of FIG. 5, a plurality of valves 40 according to the embodiment of FIG. A quadruple valve 50 is formed. Subscripts c and d are added to components of the newly added valve, and the other configuration is the same as the embodiment of FIG. Therefore, detailed description is omitted.

According to the embodiment shown in FIG.
Any type of fluid can be selected and withdrawn from the fluid outlet 8.

In the above embodiment, the case of switching from liquid to gas has been described as an example. However, in the embodiment of the present invention, switching between liquids or gases, gas-liquid mixed fluid, suspension For example, the present invention can be applied to a case where a fluid other than a liquid or a gas is handled, and in any case, it is possible to minimize mixing of a previously circulated fluid into a later circulated fluid.

FIG. 6 shows an embodiment in which the fluid processing apparatus according to the present invention is applied to a semiconductor wafer cleaning apparatus. In this embodiment, a case where a natural oxide film removal processing of a semiconductor wafer is performed is described. Will be described.

In the figure, a wafer 10 serving as a semiconductor substrate is shown.
1 is held by a wafer chuck 102, which is provided with a wafer chuck supporting cylinder 102a, and is configured to be rotated at a predetermined rotation speed by a motor (not shown).

At this time, on both surfaces of the wafer 101, the upper facing plate 111 and the lower facing plate 121 are configured to face each other while maintaining a predetermined size. An upper processing space 113 and a lower processing space 123 are formed between the lower facing surfaces 122, respectively.

The upper facing plate 111 and the lower facing plate 12
1 is provided with an upper fluid ejection hole 115 and a lower fluid ejection hole 125 near the position facing the center of the wafer 101, respectively. An upper fluid switching valve 118 and a lower fluid switching valve 128 are respectively provided in these. It is connected.

Each of the upper fluid switching valve 118 and the lower fluid switching valve 128 has a cleaning liquid supply mechanism 181
The rinsing liquid supply mechanism 182 and the drying gas supply mechanism 183 are connected to each other.

The wafer 101 is processed by rotating the wafer 101 while rotating the cleaning liquid supply mechanism 181, the rinsing liquid supply mechanism 182, the cleaning liquid supplied from the drying gas supply mechanism 183, ultrapure water, and drying gas. This is performed by supplying the fluid selected by each of the fluid switching valves 118 and 128 to the processing spaces 113 and 123 via the fluid ejection holes 115 and 125. This processing is the same as the conventional technique in which a sample is opposed to a predetermined processing member surface, and processing is performed while a processing fluid is flowing therebetween.

Next, in the apparatus shown in FIG. 6, a comparison is made between the case where a valve according to the prior art is used as the upper fluid switching valve 118 and the lower fluid switching valve 128 and the case where the valve according to the embodiment of the present invention is used. A description will be given of an experimental example.

EXPERIMENTAL EXAMPLE 1 Although the valve has the sectional structure shown in FIG. 3, it is the same as the valve according to the embodiment of the present invention, but has openings 2a to 2c.
About R and d, R = 4.0 mm, d =
In the case where the conventional valve IV of 4.0 mm is used and the sectional structure shown in FIG. 3, R = 4.0 mm, d
= 2.0 mm, that is, when the valve V according to the embodiment of the present invention is used, and when the cross-sectional structure shown in FIG. 5 is used, R = 4.0 mm and d = 2.0 mm. In the case where the valve VI according to another embodiment of the present invention was used, processing of the wafer 101 was performed.

At this time, the wafer 101 used in the processing had a diameter of 200 mm, and the surface thereof had a phosphorus concentration of 4 ×.
A wafer on which a polycrystalline silicon film doped to 10 ²⁰ (atom / cm ³ ) is formed, and while the wafer is rotated at 100 rpm, 0.5 is used as a cleaning liquid.
% Hydrofluoric acid at a flow rate of 1.0 L / min for 60 seconds, and then, while rotating the wafer at 100 rpm, ultrapure water is supplied as a rinse liquid at a flow rate of 1.0 L / min for 60 seconds. Then, 1000 rp
while rotating at 90 m, dry nitrogen as a drying gas is 90
It was circulated at a flow rate of L / min for 90 seconds.

After the processing, the surface of the wafer 101 was observed using a scanning electron microscope, the number of watermarks generated by the processing was measured, and the performance was evaluated. The results are as follows. In the case of using the valve IV, that is, the valve according to the prior art, the generation density of the watermark is 24 /
cm ² .

Next, when the valves V and VI are used,
That, when the formation density of the watermark when treated with a valve according to an embodiment of the present invention was measured, 5 / cm ² respectively 4 / cm ^2, and the the use of a valve according to an embodiment of the present invention As a result, it was found that the generation of a watermark can be greatly suppressed.

EXPERIMENTAL EXAMPLE 2 Next, similarly, a wafer having a diameter of 200 mm with a silicon oxide film formed on the surface thereof was subjected to a process using the apparatus shown in FIG. 6 using three types of valves.

The processing conditions at this time are as follows.
While rotating at pm, a solution containing 0.2% hydrochloric acid and 1% hydrogen peroxide at a temperature of 50 ° C. was used as a cleaning solution.
After the wafer is supplied at a flow rate of L / min for 60 seconds, ultrapure water is supplied as a rinse liquid at a flow rate of 1.0 L / min for 60 seconds while the wafer is also rotated at 100 rpm. It was rotated at 1000 rpm, and in this state, dry nitrogen was passed as a drying gas at a flow rate of 90 L / min for 90 seconds.

Thereafter, for each bulb, the concentration of chlorine remaining on the surface of the processed wafer 101 was measured by a total reflection X-ray fluorescence spectrometer. The performance evaluation results are as follows. When the conventional valve IV was used, the residual chlorine concentration was 1.5 × 10 ¹² atoms / cm ² .

On the other hand, the valve V according to the embodiment of the present invention,
In the processing performed using VI, each was 7.1 × ^{10 10} a
As low as tom / cm ² and 4.5 × ^{10 10} atom / cm ² , it was found that the cleaning solution in the valve was efficiently replaced with ultrapure water during rinsing.

Experimental Example 3 With the valve according to the embodiment of FIG. 5, R = 4.0 mm, d =
2.0 mm, PTFE with the same cross-sectional structure and dimensions as PCC (polyvinyl chloride) valve VI
(Fluorine resin: polytetrafluoroethylene) valve
Using VII, the same process as in Experimental Example 2 was performed. After the processing, the surface of the semiconductor wafer was observed using a scanning electron microscope, and the number of watermarks generated by the processing was measured. The performance evaluation results are as follows.

When the valve VI made of PVC was used, the watermark density became 8 pieces / cm ² , but in the treatment performed using the valve VII made of PTFE which is more hydrophobic than PVC, the watermark density was 4 pieces / cm ^2. It was found that the generation of the watermark was suppressed. Therefore, the valve according to the embodiment of the present invention has a higher PT value than a valve made of PVC.
It has been found that superior performance can be obtained by using a valve made of FE.
It is desirable to obtain good performance.

[0052]

According to the present invention, the drying performance can be improved by applying the present invention to a semiconductor wafer cleaning apparatus, and as a result, the yield of semiconductor devices can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a valve used in an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing performance of an example of a valve used in the embodiment of the present invention.

FIG. 3 is a sectional view showing another example of the valve used in the embodiment of the present invention.

FIG. 4 is a cross-sectional view showing another example of the valve used in the embodiment of the present invention.

FIG. 5 is a sectional view showing still another example of the valve used in the embodiment of the present invention.

FIG. 6 is a configuration diagram showing an embodiment in which the fluid processing apparatus according to the present invention is applied to a semiconductor wafer cleaning apparatus. DESCRIPTION OF SYMBOLS 1 Valve body 2a-2d Opening 3a-3d Valve 4a-4d Inlet side fluid passage 5a-5d Valve chamber 6 Outlet side fluid passage 7a-7d Diaphragm 8 Fluid outlet R Opening diameter d Opening length 101 Semiconductor Wafer 102 Wafer chuck 102a Wafer arm support cylinder 111 Upper facing plate 112 Upper facing surface 113 Upper processing space 115 Upper fluid ejection hole 121 Lower facing plate 122 Lower facing surface 123 Lower processing space 125 Lower fluid ejection hole 181 Cleaning liquid tank 182 Ultrapure water production equipment 183 Dry nitrogen cylinder

Continued on the front page (72) Inventor Yuichiro Tanaka 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside of Hitachi, Ltd.Production Technology Research Institute (72) Inventor Susumu Aiuchi 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa, Japan Stock Company (72) Inventor Hitoshi Oka 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Pref.

Claims (10)

[Claims] 1. A fluid processing method comprising a valve for opening and closing a fluid passage by pressing and pulling a valve body against an opening of a valve seat, and switching the fluid passage using the valve. When the diameter of the opening of the valve seat is R and the length of the fluid passage connected to the opening of the valve seat is d,
A fluid treatment method, wherein the conditions of R ≦ 20 mm and d ≦ (R / 2) are satisfied. 2. The invention according to claim 1, wherein the valve is constituted by two valves that share one valve seat and have valve bodies at both ends of an opening thereof. Fluid treatment method. 3. The fluid processing method according to claim 1, wherein at least a surface of the valve that contacts the fluid is made of a fluororesin. 4. The fluid processing method according to claim 1, wherein the content of the fluid processing is a cleaning process and a drying process of the plate-shaped sample. 5. The invention according to claim 4, wherein the plate-like sample is a semiconductor substrate, and the fluid is a mixed solution of hydrofluoric acid, a mixed solution of hydrofluoric acid and hydrogen peroxide, and a mixed solution of ammonia and hydrogen peroxide. ,
Treating the semiconductor wafer by selecting a plurality of organic amine and hydrogen peroxide, a mixed solution of hydrochloric acid, a mixed solution of hydrochloric acid and hydrogen peroxide, a mixed solution of sulfuric acid and hydrogen peroxide, pure water, and nitrogen; A fluid treatment method comprising: 6. A fluid processing apparatus comprising: a valve for opening and closing a fluid passage by pressing and pulling a valve body against an opening of a valve seat, and switching the fluid passage by using the valve. When the diameter of the opening of the valve seat is R and the length of the fluid passage connected to the opening of the valve seat is d,
A fluid treatment apparatus, wherein the conditions of R ≦ 20 mm and d ≦ (R / 2) are satisfied. 7. The invention according to claim 6, wherein the valve is constituted by two valves sharing one valve seat and having valve bodies at both ends of an opening thereof. Fluid treatment equipment. 8. The fluid processing apparatus according to claim 6, wherein at least a surface of the valve in contact with the fluid is made of a fluororesin. 9. The fluid processing apparatus according to claim 6, wherein the content of the fluid processing is a cleaning process and a drying process of the plate-shaped sample. 10. The invention according to claim 9, wherein the plate-like sample is a semiconductor substrate, and the fluid is a mixture of hydrofluoric acid, a mixed solution of hydrofluoric acid and hydrogen peroxide, and a mixture of ammonia and hydrogen peroxide. solution,
Treating the semiconductor wafer by selecting a plurality of organic amine and hydrogen peroxide, a mixed solution of hydrochloric acid, a mixed solution of hydrochloric acid and hydrogen peroxide, a mixed solution of sulfuric acid and hydrogen peroxide, pure water, and nitrogen; A fluid treatment device characterized by the above-mentioned.