JPH06333895A - Brush cleaning method in brush scrubbing process - Google Patents

Abstract

PURPOSE:To prevent a wafer from being inversely contaminated by a brush again by a method wherein all detergent is discharged from a brush cleaning tank after a brush is cleaned, and new detergent is supplied. CONSTITUTION:A rotating brush 1 is pressed against the surface of a semiconductor wafer 31 to clean it as detergent 3 is sprayed on the rotating brush 1. Thereafter, the brush 1 is wetted with detergent 3 in the brush cleaning tank 2 to be cleaned as it is rotated. After detergent 3 is discharged from the brush cleaning tank 2, and new cleaning liquid 3 is fed into the brush cleaning tank 2. By this setup, particles attached to a brush by cleaning a wafer are discharged into detergent in a brush cleaning tank. Detergent in a brush cleaning tank is all replaced after a brush cleaning operation is finished, so that particles are not left in a brush cleaning tank, and detergent is kept clean in a brush cleaning tank.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brush cleaning method in a brush scrub cleaning process, and more particularly to a method for cleaning the brush when repeatedly performing brush scrub cleaning on a wafer surface.

[0002]

2. Description of the Related Art As semiconductor devices are miniaturized, microcontamination caused by metal impurities, organic pollutants, particles, etc. adhering to the wafer surface has an increasing influence on the yield and reliability of products. There is. Therefore, in the manufacturing process of the semiconductor device,
It is important to keep the wafer surface clean.

At present, various methods are used for cleaning the wafer surface, and one of them is brush scrub cleaning. Brush scrub cleaning is a method of removing particles and the like adhering to the wafer surface by pressing the rotating brush against the surface of the wafer while applying the cleaning liquid to the rotating brush.

The brush scrub cleaning sequence will be described below with reference to FIG. For the above cleaning,
As shown in (1), a brush scrubber provided with a rotating brush 201 and a brush cleaning tank 202 for cleaning this brush is used. First, the wafer 301 to be subjected to the brush scrub cleaning is placed on the stage 401 arranged outside the brush cleaning tank 202. And the rotating brush 201
Is pulled up from the cleaning liquid 203 in the brush cleaning tank 202 and pressed against the surface of the wafer 301.

At this time, the brush 201 has the brush 2
01 from the supply nozzle 204 provided above the cleaning liquid 203
Is always supplied. As a result, the surface of the wafer 301 is cleaned by rotating the cleaning liquid 203 and the brush 201.

Next, the wafer 3 cleaned in the above process
01 and the next wafer to be washed are replaced, and the washed wafer 301 is dried. In this step, as shown in FIG.
As shown in (2), the rotating brush 201 is moved to the brush cleaning tank 202, and the brush 201 is moved to the brush cleaning tank 20.
The cleaning liquid 203 in 2 is soaked in a wet state.
At this time, the supply nozzle 20 fixed above the brush 201
4, the cleaning liquid 203 is constantly supplied to the brush 201.
This is the brush 201 during the drying and transport of the wafer 301.
This is so as not to impair the cleanliness of. Further, the cleaning liquid 203 in the brush cleaning tank 202 overflows from the drain port 206 and is drained.

Then, after the wafer 301 to be cleaned next is mounted on the stage 401, returning to FIG. 2A, the wafer 301 mounted on the stage 401 is cleaned by brush scrubbing. Repeat.

[0008]

However, the above brush scrub cleaning method has the following problems. That is, in the above method, by cleaning the wafer 301 shown in FIG. 2A, the particles adhered to the surface of the wafer 301 are washed away by the cleaning liquid 203 or adhered to the brush 201. And FIG. 2 (2)
Particles attached to the brush 201 by the cleaning of the brush 201 indicated by are discharged to the cleaning liquid 203 in the brush cleaning tank 202. However, the brush cleaning tank 202
The cleaning solution 203 therein overflows from the drain port 206 and is drained. Therefore, among the particles discharged from the brush 201 to the cleaning liquid 203, the particles floating above the cleaning liquid 203 are the drain holes 206.
However, the particles floating in the cleaning liquid 203 and the particles that settle remain in the brush cleaning tank 202 without being removed. Therefore, as the brush scrub cleaning is repeated, the particles are accumulated in the brush cleaning tank 202. When the brush 201 is immersed in the cleaning liquid 203 in the brush cleaning tank 202 in which the particles remain as described above, the particles are reattached to the brush 201, and the back contamination from the brush 201 to the wafer 301 occurs.

In order to solve the above problems, the present invention provides a method of cleaning the brush 201 during repeated steps of brush scrubbing, which aims to improve the yield and reliability of semiconductor devices. To do.

[0010]

According to the present invention for achieving the above object, in the brush scrub cleaning step, the brush is cleaned as follows. First, while cleaning liquid is applied to the rotating brush, the brush is pressed against the surface of the semiconductor wafer to clean the surface of the semiconductor wafer, and then the brush is rotated while being applied to the cleaning liquid in the brush cleaning tank. To wash. Then, the cleaning liquid in the brush cleaning tank is drained, and then the cleaning liquid is supplied into the brush cleaning tank.

[0011]

The particles adhered to the brush by cleaning the surface of the wafer are discharged to the cleaning liquid in the brush cleaning tank. Since the cleaning liquid in the brush cleaning tank is all replaced after the cleaning of the brush is completed, the particles do not remain in the brush cleaning tank, and the cleaning liquid in the brush cleaning tank is kept clean.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an example of a brush cleaning sequence in the brush scrub cleaning process of the embodiment. The brush scrubbing device used in the embodiment includes a rotating drum brush 1 and a brush cleaning tank 2 as shown in FIG. Above the brush 1, there is a cleaning liquid 3 on the brush 1.
The supply nozzle 4 for supplying the is fixed. The brush 1 provided with the supply nozzle 4 is freely movable in the brush cleaning tank 2 and on the stage 41 on which the wafer 31 placed outside the brush cleaning tank 2 is mounted.
Further, the brush cleaning tank 2 is provided with a first drain pipe 5. The drain port 6 of the first drain pipe 5 is provided at a height position of several cm from the bottom surface of the brush cleaning tank 2. Further, a second drain pipe 7 is connected to the bottom surface of the brush cleaning tank 2. The drain pipe 7 is provided with a valve 8 for opening and closing the drain pipe 7.

A brush cleaning method in the brush scrub cleaning step using the brush scrubbing device having the above-described structure is performed as follows. In the first step, first, brush scrub cleaning of the wafer 31 is performed using the brush 1. Here, the rotating brush 1 is pulled up from the cleaning liquid 3 filled in the brush cleaning tank 2, and the wafer 31 is rotated with the brush 1 being rotated.
Press on the surface of. At that time, the cleaning liquid 3 is supplied from the supply nozzle 4. At this time, the valve 8 of the drain pipe 7 is closed to keep the cleaning liquid 3 in the brush cleaning tank 2 at a constant water level.

After the cleaning of the wafer 31 is completed, as shown in FIG. 1B, the rotating brush 1 is moved from above the wafer 31 to the brush cleaning tank 2 and the cleaning liquid in the brush cleaning tank 2 is moved. Wet the brush 1 with 3 and wash. Here, following the above process, the cleaning liquid 3 is continuously supplied to the brush 1 from the supply nozzle 4. The valve 8 of the drain pipe 7 is continuously closed.

Then, as shown in FIG. 1C, a second step is performed. In this step, while supplying the cleaning liquid 3 from the supply nozzle 4 to the rotating brush 1, the valve 8 is opened to drain the cleaning liquid 3 in the brush cleaning tank 2 from the drain pipe 7. After that, as shown in FIG. 1D, the third step is performed. In this step, the valve 8 is closed after all the dirty cleaning liquid 3 in the brush cleaning tank 2 is drained. Further, the cleaning liquid 3 is continuously supplied from the supply nozzle 4.

On the other hand, the replacement of the wafer 31 which has been cleaned in the sequence of FIG. 1 (1) with the wafer to be cleaned next on the stage 41 and the drying of the cleaned wafer 31 is performed from the above-mentioned FIG. This is performed in parallel with the sequence shown in FIG.

Then, in the sequence shown in FIG. 1 (4), after the cleaning liquid 3 has accumulated in the brush cleaning tank 2 until it overflows from the drain port 6, the process returns to the sequence in FIG. Wafer 3 placed on top
1. Wash 1 Thereafter, the above FIG. 1 (2) to FIG. 1 (4)
The sequence is repeated in sequence.

When the brush is cleaned in the brush scrub cleaning process according to the above sequence, first, the wafer 3
The particles adhered to the surface of No. 1 adhere to the brush 1 by cleaning the wafer 31. Then, the particles attached to the brush 1 are discharged to the cleaning liquid 3 in the brush cleaning tank 2 by cleaning the brush 1. Brush 1
After the cleaning is completed, the cleaning liquid 3 in the brush cleaning tank 2 is drained, and new cleaning liquid 3 is supplied from the supply nozzle 4 into the brush cleaning tank 2. Therefore, particles do not accumulate in the brush cleaning tank 2. Therefore, in the next repeating step, the brush 1 is cleaned in the new cleaning liquid 3. Further, since the cleaning liquid 3 is constantly supplied from the supply nozzle 4, the brush 1 is not dried and its cleanliness is maintained.

The brush cleaning sequence shown in the above embodiment may be performed every time the wafer 31 is repeatedly cleaned. Thus, if the cleaning liquid 3 in the cleaning tank 2 is frequently replaced, for example, when the brush cleaning tank 2 is made of metal, the metal 31 eluted from the brush cleaning tank 2 into the cleaning liquid 3 is reversely contaminated to the wafer 31. Can be prevented. Further, the brush cleaning sequence may be performed when the number of particles in the cleaning liquid 3 in the brush cleaning tank 2 increases. In this case, the cleaning liquid 3 saves water.

[0020]

As described above in detail in the embodiments,
According to the brush cleaning method in the brush scrub cleaning step of the present invention, after cleaning the brush, all the cleaning liquid is drained from the brush cleaning tank and a new cleaning liquid is supplied. The cleaning liquid of is kept clean. Therefore, in the brush scrub cleaning process,
Back contamination from the brush to the wafer is prevented, and the yield and reliability of the semiconductor device are expected to improve.

[Brief description of drawings]

FIG. 1 is a diagram showing a sequence of an embodiment.

FIG. 2 is a diagram showing a sequence of a conventional example.

[Explanation of symbols]

 1 brush 2 brush cleaning tank 3 cleaning liquid 31 wafer

Claims (1)

[Claims] 1. A method of cleaning the brush when repeating the step of cleaning the surface of the wafer with a brush, which comprises pressing the brush against the surface of the wafer while applying a cleaning liquid to the rotating brush. After cleaning the surface of, the first step of cleaning the brush by wetting the brush with the cleaning solution in the brush cleaning tank while rotating the brush, and the first step of draining the cleaning solution in the brush cleaning tank. A method of cleaning a brush in a brush scrub cleaning step, which comprises performing the step 2 and a third step of supplying a cleaning liquid into the brush cleaning tank.