JPH08131977A - Apparatus and method for washing wafer - Google Patents

Abstract

PURPOSE: To wash wafers so as to prevent particles from remaining on the wafers after washing. CONSTITUTION: In a wafer washing apparatus, a step of ejecting a washing soln 3 from the bottom of a washing tank 1 to allow the same to overflow from the upper part of the tank and a step of discharging the washing soln. from the lower part of the tank 1 are repeated at least once to wash a plurality of the wafers 5 supported on a wafer support device 6 in parallel. Therefore, the drain valve 4 of the washing soln. 3 is provided to the washing tank 1 so that the lower part of at least one side wall 1b crossing the direction parallel to the surfaces of the wafers 5 of the washing tank 1 is opened and a wafer washing method is constituted so as to repeatedly perform the ejection/overflow →discharge of the washing soln. 3 at least once.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate cleaning apparatus and a cleaning method, and more particularly to a cleaning apparatus and a cleaning apparatus capable of picking up contaminants called particles without adhering to the substrate after cleaning with pure water for finishing. Regarding the method.

[0002]

2. Description of the Related Art Improving the manufacturing process is indispensable for improving the performance and reliability of semiconductor devices, but the cleaning process is very important. Since the surface of a semiconductor device is very sensitive, the stability and reproducibility of the device are determined by how to reduce the contamination of the surface, that is, how the cleaning is performed perfectly. Therefore, various cleaning methods are adopted depending on what kind of contaminant is attached to the element surface.

However, after removing any contaminants, the oil-based cleaning liquid is replaced with an aqueous cleaning liquid, and then the aqueous cleaning liquid is replaced with pure water. The cleaning process, which should be called finishing, is so-called pure water cleaning. is there. That is, it is desirable that the final cleaning is performed with pure water and the surface is dried in a clean state with no contaminants.

FIG. 5 is a schematic sectional view showing a conventional substrate cleaning apparatus in the order of steps. In the figure, 1 is a cleaning tank, 1a is an overflow part, 1c is a bottom part, 2 is a water supply board, 2a is a jet hole, 3 is a cleaning liquid, 4 is a drain valve, 5 is a substrate, 6 is a substrate support, and 6a is Side pocket, 6b lower pocket, 8 particles,
10 is a cleaning device.

In FIG. 5, a cleaning apparatus 10 has a water supply board 2 arranged below a box-shaped cleaning tank 1, and the water supply board 2 is provided.
For example, in the case of washing with pure water, pure water is vigorously ejected from the ejection holes 2a provided on the upper surface of the. In addition, the cleaning liquid 3 accumulated in the cleaning tank 1 overflows at the upper edge 1a of the cleaning tank 1.
Is overflowing from. Further, a drain valve 4 is provided on the bottom portion 1c of the cleaning tank 1 below the water supply board 2.
When the drain valve 4 is opened, the cleaning liquid 3 in the cleaning tank 1 is rapidly discharged, so-called quick down can be performed.

A plurality of substrates 5 such as wafers are supported in parallel by a substrate support 6 called a carrier or a basket. The substrate 5 is normally supported by the three pockets 6a and 6b of the substrate support 6. The substrate support 6 is carried into the cleaning tank 1 by a robot hand (not shown) or the like. Then, the cleaning liquid 3 is ejected from the ejection holes 2a of the water supply board 2, and the cleaning tank 1 is eventually filled up and overflows from the overflow portion 1a. Next, the drainage valve 4 of the bottom portion 1c is opened to discharge the cleaning fluid 3 at once. A series of cleaning steps are completed by repeating the operation of jetting / overflowing → discharging the cleaning liquid 3 7 times or 10 times, and the substrate support 6 supporting the substrate 5 is carried out of the cleaning tank 1.

[0007]

By the way, since the substrate 5 and the substrate support 6 before the cleaning process have been subjected to various treatment processes such as film formation and etching, fine fragments, pieces, dust, etc. So-called particles 8 are attached. The particles 8 adhere to not only the surface of the substrate 5 but also the vicinity of the pockets 6a and 6b.
In the cleaning process, while the cleaning liquid 3 is overflowed from the overflow portion 1a on the one hand, the drain valve 4 is opened on the other hand and the discharge is repeated several times so that the particles 8 are discharged together with the cleaning liquid 3. I have to.

By the way, in the conventional cleaning device 10,
The drainage valve 4 is provided on the bottom portion 1c directly below the cleaning tank 1. Therefore, there is a tendency that the particles 8 cannot be removed due to the flow of the cleaning liquid 3 at the time of discharging. That is, the lateral pocket 6a provided on the lateral portion of the substrate support 6
As can be seen from the flow of the cleaning liquid 3 shown by the broken line in the vicinity of, the cleaning liquid 3 is effectively washed both when it is jetted and when it is discharged, and the particles 8 rarely stay. However, the lower pocket 6b of the substrate support 6 is difficult to be washed because of the flow of the cleaning liquid 3 when the cleaning liquid 3 is jetted and discharged. As a result, the particles 8 are in the lower pocket.
It remains in the vicinity of the gap between 6b and the substrate 5 and cannot be removed easily.

Therefore, the present invention provides a cleaning device and a cleaning method in which the flow of the cleaning liquid at the time of discharging the cleaning liquid in the cleaning device effectively cleans the lower pocket of the substrate support tool to prevent residual particles. It is intended to be provided.

[0010]

[Means for Solving the Problems] The above-mentioned problem is solved by at least one of a step of causing a cleaning liquid to spout from the lower side of the cleaning tank while overflowing from the upper side, and a step of discharging the cleaning liquid from the lower side.
In a substrate cleaning apparatus for cleaning a plurality of substrates supported in parallel by a support tool repeatedly, a drain valve for discharging the cleaning liquid intersects a direction parallel to the substrate surface of the cleaning tank. At least one side wall of the substrate cleaning device configured to be opened so that the lower part of the side wall is opened, and a substrate support tool in which a plurality of substrates are supported in parallel are lowered into a cleaning tank, and the cleaning liquid is applied from below. A first step of overflowing the cleaning solution from the upper part while discharging the cleaning solution by opening a drain valve provided at a lower part of a side wall of the cleaning tank intersecting a direction parallel to the substrate surface. The second step is repeated at least once, and then the cleaning method is carried out by raising and removing the substrate support from the cleaning tank.

[0011]

Since the drain valve provided in the conventional cleaning apparatus is provided at the bottom of the cleaning tank, even if the cleaning solution is quickly downed, the drain valve provided in the lower part of the substrate support due to the flow path of the cleaning solution. Although the pocket was hard to be washed and particles remained, in the present invention, the drainage valve is provided below the side wall intersecting the plane parallel to the substrate. Then, when the cleaning solution is quickly downed, the lower pocket of the substrate supporting tool is washed down from the lateral direction and flows down.

As a result, the lower pocket of the substrate support, on which the particles were particularly likely to remain, is effectively washed, so that the remaining particles can be greatly reduced.

[0013]

FIG. 1 is a perspective view of a cleaning apparatus according to a first embodiment of the present invention, FIG. 2 is a process diagram schematically showing a cleaning method according to the first embodiment of the present invention, and FIG. FIG. 4 is a process diagram schematically showing the effect of the present invention in terms of the number and distribution state, and FIG. 4 is a cleaning method according to the second embodiment of the present invention. In the figure, 1 is a cleaning tank, 1a is an overflow portion, 1b is a side wall, 2 is a water supply plate, 2a is a jet hole, 3 is a cleaning liquid, 4 is a drain valve, 4a is a valve body, 4b is an opening / closing means, 5 is Substrate, 6 substrate support, 6a lateral pocket,
6b is a lower pocket, 7 is a processing tank, 8 is particles,
10 is a cleaning device.

[Embodiment 1] The cleaning apparatus shown in FIGS.
In 10, a substrate support 6 such as a carrier or a basket for supporting a plurality of substrates 5 such as semiconductor wafers in parallel is placed in a box-shaped cleaning tank 1 made of plastic, for example, by a robot hand (not shown). Carried in and washed.

A water supply board 2 made of, for example, plastic is disposed below the cleaning tank 1, a cleaning liquid 3 is supplied from a liquid source (not shown), and a plurality of ejection holes 2a are provided on the upper surface of the water supply board 2. For example, in the case of a pure water cleaning device, pure water or the like is spouted out vigorously. The cleaning liquid 3 ejected from the ejection holes 2a rises vigorously through the gap between the substrates 5 supported by the substrate support 6. The cleaning liquid 3 accumulated in the cleaning tank 1 overflows from the overflow portion 1a at the upper edge of the cleaning tank 1. Further, a drain valve 4 is provided below the side wall 1b of the cleaning tank 1 which intersects a plane parallel to the surface of the substrate 5 supported by the substrate support 6.

The drain valve 4 is constructed so that the valve body 4a can be opened and closed by being driven by an opening / closing means 4b such as a plastic air cylinder. The valve body 4a is preferably as large as possible so that the cleaning liquid 3 in the cleaning tank 1 can be quickly downed when opened.

In FIG. 2, the substrate support 6 which has been subjected to various kinds of processing and taken out from the processing bath 7, and the substrate 5 supported by the substrate support 6, particularly pockets 6a and 6b for supporting the substrate 5. The particles 8 remain in the vicinity of.

The substrate support 6 is put in the cleaning tank 1, and the cleaning liquid 3 is jetted from the lower water supply plate 2 and is washed while overflowing from the overflow portion 1a. In the first jetting / overflowing step, the lateral pockets 6a of the substrate support 6 are washed from the lower side, so that the particles 8 are well removed.
However, in the lower pocket 6b, since the flow of the cleaning liquid 3 is from directly below, the particles 8 are not effectively removed.
When the first step of jetting / overflowing is continued for, for example, 1 minute, the drainage valve 4 is opened to drain the cleaning fluid 3 at once.

In the second step of discharging the cleaning liquid 3, the lateral pocket 6a is washed from the upper side by the flowing cleaning liquid 3 as shown by the broken line in the flow path. Further, since the lower pocket 6b is washed from the side by the discharged cleaning liquid 3, the particles 8 are effectively removed.

Operation of jetting / overflowing and discharging of the cleaning liquid 3,
That is, after repeating the first step and the second step, for example, seven times, a series of cleaning steps are completed by pulling up the substrate support 6 from the cleaning tank 1 in the third step.

The effect of the present invention in which the drain valve 4 has such a structure is described in FIG. That is, here, the number of particles 8 of 0.2 μm or more remaining in a 6-inch semiconductor wafer after passing through the pure water cleaning device 10 will be compared with the embodiment.

According to the conventional cleaning device, the particles 8
1,000 to 2,000 remain, and the map data of the particles 8 on the wafer surface can be seen to clearly show how the particles 8 remain along the flow of the cleaning liquid 3. On the other hand, according to the cleaning apparatus of the present invention, the number of remaining particles 8 is 200 to 500, and it can be seen from the map data of the particles 8 on the wafer surface that the number is extremely reduced.

[Embodiment 2] In FIG. 4, this cleaning device is used.
In 10, the substrate 5 supported by the substrate support 6 of the cleaning tank 1
Two side walls 1b that intersect and are parallel to the surface parallel to the surface of
A drainage valve 4 is provided in each of the lower parts of the.

The substrate support 6 that has been subjected to various kinds of processing and taken out from the processing bath 7 and the substrate 5 supported by the substrate support 6 include pockets 6a for supporting the substrate 5,
Particles 8 remain near 6b.

In the case of this cleaning device 10, since the drain valve 4 is provided facing the left and right of the cleaning tank 1, the cleaning liquid 3
First step of ejecting / overflowing the cleaning liquid → the fourth process of discharging the cleaning liquid 3 to the right side → the first process → the fifth process of discharging the cleaning liquid 3 to the left side, and then the third process If the substrate support tool 6 is pulled up from the cleaning tank 1 in the step (1), a series of cleaning steps is completed.

That is, the drainage valves 4 are opened alternately to the left and right when discharging, so that the cleaning liquid 3 flows down alternately to the left and right. Then, since the lower pocket 6b is washed from both right and left sides, the particles 8 can be removed more effectively.

Although the substrate is illustrated as if it is a semiconductor wafer, it can be applied to a glass substrate used for a flat display device, for example, and the substrate may be rectangular instead of circular. Also, there are 3 pockets for the substrate support.
Although the case of individual pieces has been illustrated, the present invention is effective even when there are two lower pockets and four-point support is provided.

[0028]

According to the present invention, the drain valve of the cleaning tank is provided at the lower part of the side wall intersecting the plane parallel to the substrate. Therefore, when the cleaning solution is quickly down, it flows down while flushing the lower pocket of the substrate support from the lateral direction.

As a result, after undergoing various treatments prior to cleaning, the vicinity of the lower pocket of the substrate support where particles are likely to remain is effectively cleaned, and the remaining particles can be greatly reduced. Therefore, the present invention largely contributes to the improvement of the yield of the wafer process in the manufacturing process of the semiconductor device.

[Brief description of drawings]

FIG. 1 is a perspective view of a cleaning device according to a first embodiment of the present invention.

FIG. 2 is a process drawing that schematically shows the cleaning method according to the first embodiment of the present invention.

FIG. 3 is an effect of the present invention viewed from the number and distribution of particles.

FIG. 4 is a process diagram schematically showing a cleaning method according to a second embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view showing a conventional substrate cleaning apparatus in process order.

[Explanation of symbols]

1 Cleaning tank 1a Overflow part 1b
Side wall 2 Water supply panel 2a Jet hole 3 Cleaning liquid 4 Drain valve 4a Valve body 4b
Opening / closing means 5 Substrate 6 Substrate support 6a Horizontal pocket 6b
Lower pocket 7 Processing tank 8 Particles 10 Cleaning device

Claims (3)

[Claims] 1. A substrate cleaning apparatus for cleaning a substrate supported in parallel with a jetting direction of a cleaning liquid by ejecting the cleaning liquid from a lower portion of a cleaning tank while overflowing the upper portion of the cleaning tank. A substrate cleaning apparatus, wherein a valve is provided so that a lower portion of at least one side wall of the cleaning tank intersecting a direction parallel to the substrate surface is opened. 2. The first step is a step of lowering a substrate support tool, in which a plurality of substrates are supported in parallel, into a cleaning tank, and spouting a cleaning liquid from below while spouting the cleaning liquid from below. The step of is a step of opening the drain valve to discharge the cleaning liquid in a direction parallel to the substrate surface, and the third step is a step of raising and taking out the substrate support from the cleaning tank. The first step and the second step are at least 1 in that order.
A method for cleaning a substrate, characterized in that the method is repeatedly performed, and then a third step is performed. 3. A fourth step is a step of opening one of the drain valves to discharge the cleaning liquid, and a fifth step is a step of opening the other drain valve to open the cleaning liquid. And a step of discharging the first step, a fourth step, and a first step,
The substrate cleaning method according to claim 2, wherein the fifth step is repeated at least once in that order, and then the third step is performed.