JP3250516B2 - Washing device and washing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for rinsing water, and more particularly to a method and apparatus for rinsing a wafer surface with high throughput.

[0002]

2. Description of the Related Art Conventionally, as a device for washing a wafer (semiconductor substrate) which has been subjected to etching, washing, etc., a single-wafer spin washing method (referred to as "known example 1") as shown in FIG.
However, although the water washing effect on the wafer surface is high, the throughput is low because the processing is performed one by one. In this method, pure water is supplied from above while the wafer is rotated to clean the wafer surface.

Further, as shown in FIG. 6, a conventional batch dip washing method using only water injection (hereinafter referred to as "known example 2").
In the method, since the flow rate of pure water in the washing tank is limited by the flow rate of the supplied pure water, the effect of washing the wafer surface with water is low. For example, Japanese Patent Application Laid-Open No. 4-990 discloses a conventional water washing apparatus of this kind.
Japanese Patent Publication No. 25 discloses a washing tank provided with a drain port at the bottom,
A mounting plate that is provided above the position of the drain port and on which the carrier containing the semiconductor substrate is mounted, and a nozzle for discharging pure water on the inner surface portion are provided. A flushing device has been proposed in which pure water is discharged vertically from a nozzle of a lid at a top portion of the flushing tank to between semiconductor substrates.

[0004]

As described above, the conventional rinsing method has problems that the throughput is low and the effect of rinsing the wafer surface is low.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide a water washing method and apparatus for improving the efficiency of cleaning the wafer surface and improving the throughput.

[0006]

According to the present invention, in order to achieve the above object, the present invention provides a method of washing a wafer with water, wherein pure water in a washing tank is forcibly drained using a circulating pump at an initial stage of the washing, and is then filtered. Washing is performed by supplying filtered circulating water, and at the end of washing after a certain period of time, circulation is stopped and pure water is supplied to the washing tank, so that water is washed with fresh pure water.

The apparatus according to the present invention comprises a washing tank for accommodating a wafer to be washed, and a valve for controlling the supply and shutoff of pure water to the washing tank , which are disposed upstream and downstream of the washing tank. the first is a second valve, a filter for filtering the water from the washing tank, forcibly drained from the washing tank is supplied to the filter, the filtered water in the filter to the water washing tank A circulation pump for circulating and supplying, and a third valve for controlling supply and cutoff of circulating water supplied from the circulation pump to the washing tank,
In the initial stage of washing, the first and second valves are closed, and pure water in the washing tank is forcibly drained using the circulation pump.
After rinsing with circulating water, at the end of rinsing after a certain period of time, the third valve is closed, the circulating pump is stopped, the first and second valves are opened, and pure water is rinsed with pure water. By supplying the water to the tank, water washing is performed with fresh pure water.

[0008]

Embodiments of the present invention will be described below. In an embodiment of the present invention, referring to FIG. 1, in the initial stage of washing, a circulating pump (5) is used.
The pure water in the washing tank (1) is forcibly drained, purified by the filter (4), and then supplied again into the washing tank (1) to perform washing with circulating water. Then, at the end of the water washing after a certain period of time, the circulation is stopped, and pure water is supplied to the water washing tank, so that water washing is performed with fresh pure water.

[0009] washing apparatus of the present invention, washing tank for accommodating the cleaned wafer in a preferred embodiment (1), a valve for controlling the supply and cutoff of the pure water washing tank, the washing tank the first is disposed on the water supply side and the outlet side respectively, the second valve (2 a, 2b), a filter (4) for filtering the water washing tank, forcibly drained from the washing tank is supplied to a filter, a circulation pump for feeding circulating the filtered water in the filter in the washing tank (5), controls the supply and interruption of the supplied circulating water of the washing tank from the circulation pump And a third valve (3). Hereinafter, the present invention will be described in detail with reference to examples.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the configuration of one embodiment of the present invention. Referring to FIG. 1, in one embodiment of the present invention, a washing tank 1 for storing and washing a wafer, a pure water supply opening / closing valve 2a, 2b, 3; a circulation pump 5 for circulating pure water; The apparatus is provided with a filter 4 for purifying water and a pure water supply port 6 for supplying pure water.

The operation of one embodiment of the present invention will be described with reference to FIG. The wafer 7 is immersed in the washing tank 1 filled with pure water, and in the initial stage of washing, the pure water supply opening / closing valve 2a provided on the pure water supply side upstream of the washing tank 1 and the upstream of the washing tank 1 are provided. The pure water supply opening / closing valve 2b provided on the pure water drain side is closed, and the pure water supply opening / closing valve 3 provided between the downstream of the circulation pump 5 and the upstream of the opening / closing valve 2b.
Is opened, and the circulation pump 5 is operated.

The pure water in the washing tank 1 is forcibly drained from the washing tank 1 by the circulation pump 4, purified by the filter 5, and then supplied to the washing tank 1 again, so that the pure water is recirculated. Wash with water. At the end of washing after a certain period of time,
The pure water supply opening and closing valves 2a and 2b are opened, the pure water opening and closing valve 3 is closed, and the circulation pump 4 is stopped. Then, pure water is supplied to the washing tank 1 from a pure water supply port 6, and the pure water is washed with fresh pure water.

In this embodiment, when the water washing was performed, the total washing time was 3 minutes, the initial washing with circulating water was performed for 1.5 minutes, and the washing with final water injection was performed for 1.5 minutes.

The flow rate of pure water supplied to the washing tank at the time of pouring water is 1200 L / H, which is the same as that of the known example 2.

The water supply capacity of the circulation pump 5 is 300
It is 0 L / H, and the flow rate of pure water supplied to the rinsing tank at the time of circulating water rinsing is more than twice that at the time of water injection rinsing.

The operations of the pure water supply opening / closing valves 2a and 2b and the circulation pump 5 are automatically controlled by a microcomputer or the like, and when the pure water supply opening / closing valves 2a and 2b are closed,
The pure water supply opening / closing valve 3 is “open” and the circulation pump 4 is “operating”, or vice versa.

According to the present embodiment, in the initial stage of washing, the drained pure water is circulated, supplied again to the washing tank, and washed with the circulating water, so that a large amount of pure water is not required. Water usage can be reduced. FIG. 2 is a diagram showing the amount of pure water used per day in one example of the present invention in comparison with Known Example 1 (see FIG. 5) and Known Example 2 (see FIG. 6).

Further, according to this embodiment, by performing circulation at a high speed, contaminants on the wafer surface can be effectively washed with water. FIG. 3 is a diagram showing the concentration of residual ions on the wafer surface according to the present embodiment in comparison with known examples 1 and 2. FIG. 3 also shows that the present embodiment has less residual ions than the known example 2.

Further, according to the present embodiment, the washing effect is improved and the throughput is improved. FIG. 4 is a diagram comparing the throughputs of the known examples 1 and 2 as a comparative example and the present embodiment. In this embodiment, the number of processed wafers per hour is about 500, and the number of processed wafers per unit time can be much larger than that of the known examples 1 and 2.

Next, a second embodiment of the present invention will be described below. In the second embodiment of the present invention, the configuration is the same as that shown in FIG.

Referring to FIG. 1, a wafer is immersed in a rinsing tank 1 filled with pure water, and in the initial stage of rinsing, a supply amount of 0 to 100% pure water is controlled from pure water supply opening / closing valves 2a and 2b.
The pure water supply opening / closing valve 3 is opened, and the circulation pump 5 is operated. Pure water in the washing tank 1 is forcibly drained from the washing tank by the circulation pump 4 and purified by the filter 4.
By supplying the water to the washing tank 1 again, washing with circulating water is performed. At the same time, pure water is supplied from the pure water supply port 6, and water washing is performed with fresh pure water. At the end of the washing after a lapse of a certain time, the pure water supply opening / closing valves 2a and 2b are opened, the pure water opening / closing valve 3 is closed, and the circulation pump 4 is stopped. Pure water is supplied to the washing tank 1 from a pure water supply port 6,
Rinse with fresh pure water.

In this way, at the time of rinsing with circulating water at the initial stage of rinsing, fresh pure water is also supplied at the same time, so that the flow rate of pure water in the rinsing tank is increased and the effect of purifying the wafer is enhanced.

In this embodiment, the total washing time is 3 minutes,
The initial washing with circulating water was performed for 1.5 minutes, and the final washing with water was performed for 1.5 minutes. The flow rate of pure water supplied to the rinsing tank at the time of rinsing with water is 1200 L / H, which is the same as that in the known example 2. In addition, the water supply capacity of the circulation pump is 3000 L / H, and the flow rate of pure water supplied to the rinsing tank at the time of circulating water washing is more than twice that at the time of water injection washing.

[0024]

As described above, according to the present invention,
The following effects are obtained.

The first effect of the present invention is that the amount of pure water used can be reduced without requiring a large amount of pure water.

The reason for this is that, in the present invention, in the initial stage of washing, the drained pure water is circulated and supplied to the washing tank again to perform washing with the circulating water.

A second effect of the present invention is that by performing circulation at a high speed, contaminants on the wafer surface can be effectively washed with water.

The third effect of the present invention is that the water washing effect is improved and the throughput is improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing the amount of pure water used as an effect of the embodiment of the present invention in comparison with known examples 1 and 2.

FIG. 3 is a diagram showing, as an operational effect of the embodiment of the present invention, a residual ion concentration on a wafer surface in comparison with known examples 1 and 2.

FIG. 4 is a diagram showing the number of processed wafers per unit time in comparison with the known examples 1 and 2, as an operational effect of the embodiment of the present invention.

FIG. 5 is a diagram for explaining a first known example.

FIG. 6 is a diagram for explaining a second known example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rinse tank 2, 3 Pure water supply opening / closing valve 4 Filter 5 Circulation pump 6 Pure water supply port 7 Wafer

Claims (4)

(57) [Claims] When washing a wafer with water, at the initial stage of washing, pure water in a washing tank in which the wafer is immersed is forcibly drained using a circulation pump, and circulating water filtered by a filter is supplied to the washing tank. Water washing by supplying water, and at the end of the water washing after a certain time, circulating is stopped and pure water is supplied to the water washing tank, so that water is washed with fresh pure water. . 2. A rinsing tank for accommodating a wafer to be cleaned, and a valve for controlling the supply / cutoff of pure water to the rinsing tank , the valve being disposed upstream and downstream of the rinsing tank , respectively. first circulation and the second valve, a filter for filtering the water from the washing tank, is forcibly drained from the washing tank is supplied to the filter, the filtered water in the filter to the water washing tank A circulating pump for supplying the circulating water; and a third valve for controlling supply and shutoff of circulating water supplied from the circulating pump to the rinsing tank. 3. Initially, the first and second valves are closed, pure water in the washing tank is forcibly drained using the circulating pump, and washed with circulating water filtered by the filter. The third valve is closed and the circulating pump is stopped at the end of the water washing after the elapse of a predetermined time, and the first and second pumps are stopped.
The flushing device according to claim 2, wherein the valve is opened to supply pure water to the flushing tank, thereby performing flushing with fresh pure water. 4. At the initial stage of washing, pure water is supplied to the washing tank while the first and second valves are appropriately opened.
The pure water in the washing tank is forcibly drained using the circulating pump, washed with circulating water filtered by the filter, and at the end of washing after a certain period of time, the third valve is closed. Stopping the circulation pump, opening the first and second valves, and supplying pure water to the washing tank,
3. The water washing device according to claim 2, wherein the water washing is performed with fresh pure water.