JPH0997778A - Cleaning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent outside air from penetrating into a cleaning tank and the surface of a semiconductor wafer from drying up in a semiconductor wafer cleaning process. SOLUTION: A cleaning device is equipped with a water feed pipe 3c which feeds water into a cleaning tank 3 to dip a work 5 into cleaning water, an exhaust pipe 3b which exhausts the tank 3 of solution, and a first shower 6 which is provided adjacent to the opening 3d of the tank 3 to spray solution against the work 5, wherein a second shower 7 which spouts out water adjacent to the opening 3d so as to form a water curtain 7a to prevent outside air from penetrating into the tank 3 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning device used for cleaning semiconductor wafers after chemical treatment.

[0002]

2. Description of the Related Art In a semiconductor device manufacturing process, there is a process using liquid chemicals such as chemical cleaning and etching. Conventionally, a cleaning apparatus for cleaning a semiconductor wafer after chemical treatment in these steps will be described with reference to FIG. In the figure, 11
Is a conventional cleaning device, 12 is an outer tank of a double cleaning tank, and a bottom 12a of the outer tank has a first drain port 12b, and 13 is an outer tank 1.
In the inner tank arranged inside 2, the second drainage port 1 which keeps the bottom portion 13a of the inner tank airtight at the bottom portion 12a of the outer tank and penetrates through
It has 3b and a water supply port 13c. Reference numeral 14 denotes a wafer stand for standing and holding a plurality of semiconductor wafers 15 in a state of being separated one by one at regular intervals, and 16 denotes a shower for spraying all the semiconductor wafers 15 surface of the wafer stand 14 within the spray range 16a.

A method of using this cleaning device will be described below. Close the solenoid valve (not shown) of the second drain port 13b,
A solenoid valve (not shown) of the water supply port 13c is opened to supply pure water, and overflows from the upper part of the inner tank 13. At this time, the pure water that overflows and has entered the outer tank 12 is drained from the first drain port 12b of the bottom portion 12a of the outer tank. Subsequently, the wafer stand 14 on which the semiconductor wafer 15 is set up
Is immersed in the inner tank 13. This state is left for a predetermined time.
At this time, although not shown, ultrasonic cleaning may be applied, nitrogen may be bubbled, or the wafer stand may be rocked by hand to enhance the cleaning effect. Then, after closing the electromagnetic valve of the water supply port 13c and interrupting the water supply, the electromagnetic valve of the second drain port 13b is opened to completely drain all the pure water in a short time. In this way, since the drainage is natural drainage, the second drainage port 13b is made as thick as possible. In addition, when the water in the inner tank 13 is completely drained, pure water for repeated cleaning is immediately supplied in a short time until the semiconductor wafer 15 is completely immersed and overflowed and a certain time elapses. . This operation is repeated several times for washing. The supply and drainage of pure water are repeated to accelerate the cleaning effect and to reduce the amount of pure water used until the same cleaning effect is reached.

During this cleaning, if water drops on the semiconductor wafer 15 become dusty and dry, the semiconductor wafer 1
5 Stain remains on the surface. Removal of this stain is difficult even with chemicals. Therefore, in order to prevent the surface of the semiconductor wafer 15 from drying during drainage of the inner tank 13, pure water is sprayed from the shower 16 while the semiconductor wafer 15 is exposed by the drainage of pure water in the inner tank 3. This is to prevent water droplets on the surface of the semiconductor wafer 15 from drying after absorbing dust in the air.

[0005]

In the above cleaning apparatus, it is not possible to wet the entire surface of a semiconductor wafer set up at a narrow interval with a shower. Therefore, even if water is supplied to and drained from the inner tank in a short time, the air in the upper part of the tank of the cleaning device is drawn in during drainage, and some of the water droplets that have come into contact with the dust in the air dries and stains occur. Was.

[0006]

The present invention has been proposed in order to solve the above problems, and has a tank having a water supply pipe for supplying water for immersing an object to be cleaned and a drainage pipe for draining water.
In a cleaning device having a first shower for injecting an object to be cleaned in the vicinity of an opening of a tank, a second shower is provided which forms a water curtain for injecting in the vicinity of the opening and preventing outside air from flowing into the tank. The cleaning device is provided. Also provided is a cleaning device that sprays water from the second shower onto the inner wall of the tank, or sprays water from the second shower while the object to be cleaned is exposed due to drainage of the tank. Further, the present invention provides a cleaning device in which the second shower ejects water droplets of 50 to 400 μm and the ejection port of the second shower has a slit shape.
Furthermore, a cleaning device for spraying from the first shower in a mist state is provided.

[0007]

DETAILED DESCRIPTION OF THE INVENTION The cleaning apparatus of the present invention will be described with reference to FIG. In the figure, 1 is a cleaning device of the present invention, 2 is an outer tank of a double cleaning tank, a bottom 2a of the outer tank has a first drain port 2b, and 3 is a book disposed inside the outer tank 2. In the inner tank corresponding to the tank in the claims of the invention, the bottom portion 3a of the inner tank is the bottom portion 2 of the outer tank.
It has a second drainage port 3b and a water supply port 3c which are kept airtight in a and penetrate therethrough. Reference numeral 4 is a wafer stand for standing and holding a plurality of semiconductor wafers 5 in a state where they are separated one by one at regular intervals, and 6 is a surface of all the semiconductor wafers 5 of the wafer stand 4 within an injection range 6a from an opening 3d to an inner tank. Is a first shower that is sprayed toward the inner surface 3e of the. Reference numeral 7 is a second shower arranged in the upper center of the inner tank 3 which is a feature of the present invention. The second shower 7 forms a water curtain 7a and the upper end 2c of the outer tank.
Pure water is sprayed onto the inner surface 2d of the lower outer tank.

A method of using this cleaning device will be described below. The electromagnetic valve (not shown) of the second drain port 3b is closed, the electromagnetic valve (not shown) of the water supply port 3c is opened, and pure water is supplied.
Overflow from the upper part of the inner tank 3. At this time, the pure water that overflows and enters the outer tank 2 is at the bottom 2a of the outer tank.
The water is drained from the first drain port 2b. Subsequently, the wafer stand 4 on which the semiconductor wafer 5 is placed is immersed in the inner tank 3. The pure water is left to flow for a predetermined time. At this time, although not shown, ultrasonic cleaning may be applied, nitrogen may be bubbled, or the wafer stand 4 may be swung by hand or machine to enhance the cleaning effect. Next, water supply port 3
After closing the solenoid valve of c and interrupting the water supply, the second drain port 3b
Open the solenoid valve to completely drain all pure water in a short time. In this way, since the drainage is natural drainage, the second drainage port 3b is made as thick as possible. Further, when the water in the inner tank 3 is completely drained, pure water for repeated cleaning is immediately supplied in a short time until the semiconductor wafer 5 is completely immersed. This is also supplied in a short time in order to prevent the semiconductor wafer 5 from drying. This operation is repeated several times for washing. Then, the semiconductor wafer 5 is placed on the wafer stand 4
The whole wafer is immersed in alcohol to remove water on the surface of the semiconductor wafer 5. This is because dust in the air adheres to water droplets adhering to the semiconductor wafer 5 and is not dried. If dust adheres to the water droplets and dries, the semiconductor wafer 5
Stain remains on the surface. Removal of this stain is difficult even with chemicals.

Further, in order to prevent the surface of the semiconductor wafer 5 from being dried during drainage, the first shower 6 is drained.
Pure water is sprayed from the nozzle toward the opening 3d. This is done by increasing the humidity around the semiconductor wafer 5,
This is to prevent water drops on the surface from drying. Therefore, it is preferable to spray in a mist state.

The second shower 7, which is a feature of the present invention, is formed by injecting pure water toward the inner surface 2d of the outer tank 2 from the water curtain 7a, and almost all of the injected pure water is in the outer tank 2. The inner air is prevented from entering the inner tank 3 by allowing it to enter the inside. Moreover, you may inject toward the inner wall 3e of the inner tank 3. The water curtain 7a may be formed with a pure water film, or may be formed without forming a film as long as air passage is prevented. The second shower 7 may be jetted when the surface of the semiconductor wafer 5 is exposed from pure water, that is, when draining.

The second shower 7 at this time is 50 to 400
Water droplets having a diameter of μm may be formed or ejected from the slit portion. Since the water of the second shower is applied to the inner wall of the outer tank over the entire circumference, the outside air does not enter the inner tank.
High humidity atmosphere is maintained and stains do not occur. By doing so, it is possible to prevent dust in the outside air from coming into contact with the semiconductor wafer 5 in the inner tank 3. This prevents dust from adhering to the surface of the semiconductor wafer 5. Therefore, no stain is generated.

[0012]

According to the present invention, since the water curtain is formed by the second shower which prevents the object to be cleaned from coming into contact with the outside air, the outside air is prevented from entering the inside of the tank. Becomes high humidity, the water drops do not dry, and dust in the outside air does not contact the semiconductor wafer, so that no stain occurs. Further, by spraying pure water in a mist form in the first shower, the semiconductor wafer under the first shower is always kept in high humidity, and the effect is further enhanced by preventing water droplets from drying.

[Brief description of drawings]

FIG. 1 is a side sectional view of a cleaning device of the present invention.

FIG. 2 is a side sectional view of a conventional cleaning device.

[Explanation of symbols]

 3 tank (inner tank) 3b drain pipe (second drain port) 3c water supply pipe (water inlet) 3d opening 5 object to be cleaned (semiconductor wafer) 6 first shower 7 second shower 7a water curtain

Claims (6)

[Claims] 1. A tank provided with a water supply pipe for immersing the object to be cleaned and a drain pipe for draining the object, and a first shower for spraying the object to be cleaned in the vicinity of the opening of the tank. In the cleaning device having the above, the cleaning device is provided with a second shower that forms a water curtain that is sprayed in the vicinity of the opening to prevent outside air from flowing into the tank. 2. The cleaning apparatus according to claim 1, wherein the water sprayed from the second shower is sprayed onto the inner wall of the bath. 3. The cleaning apparatus according to claim 1, wherein the second shower is sprayed while the object to be cleaned is exposed by draining the tank. 4. The cleaning apparatus according to claim 1, wherein the second shower sprays water droplets of 50 to 400 μm. 5. The cleaning apparatus according to claim 1, wherein the injection port of the second shower has a slit shape. 6. The cleaning device according to claim 1, wherein the first shower is sprayed in a mist state.