JPH10135175A - Wafer-cleaning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent bubbles from adhering to a wafer and foreign matters from remaining in the bottom section of a cleaning tank by successively interposing a circulating pump and a filter between a drainage port installed to the bottom of the cleaning tank and a circulating pipeline which is provided around the outer periphery of the top opening of the cleaning tank and communicates the cleaning tank with an external tank for overflow. SOLUTION: A cleaning tank 21 having a top opening has a funnel-like bottom section 23, a drainage port 25 at the center of the bottom section 23, and a drainage guiding section 29 on the surface of the bottom section 23. A circulating pipeline (drainage pipeline) 37, which is connected to the discharge port of a circulating pump 39, is connected to the drainage port 25 of the tank 21. A filter 41 is connected to the discharge port of the pump 39, and the outlet of the filter 41 is connected to the bottom face of an outer tank 45 through a circulating pipeline (supplying pipeline) 43. The outer tank 45 is provided around the top opening of the tank 21, and the outer peripheral wall 47 of the tank 45 is made higher than an external wall 21a of the cleaning tank 21 (in other words, the internal wall of the outer tank 45).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer cleaning apparatus using a chemical solution as a cleaning liquid, and more particularly, to preventing particles from adhering to a wafer when the cleaning tank is immersed.

[0002]

2. Description of the Related Art A wafer cleaning apparatus for removing dirt such as particles and organic substances on a wafer surface by using the chemical action and physical energy of a cleaning liquid together has a function of constantly filtering and circulating the cleaning liquid with a filter. There are things.

An overflow-type wafer cleaning apparatus of this type in which the cleaning liquid flows upward from below the wafer and overflows from the upper surface of the tank will be described with reference to FIG. FIG. 3 is a schematic configuration diagram showing a conventional wafer cleaning apparatus. An outer tank 3 is provided on the outer periphery of the cleaning tank 1 having an open upper surface. A drainage pipe 5 is connected to the bottom of the outer tank 3, and the drainage pipe 5 is connected to a supply port of a circulation pump 7. A filter 9 is connected to a discharge port of the circulation pump 7, and an outlet of the filter 9 is connected to a bottom surface of the cleaning tank 1 via a liquid supply pipe 11.

In the cleaning device 13 configured as described above, for example, a mixed cleaning liquid 15 such as hydrochloric acid, hydrogen peroxide, and water overflows from the cleaning tank 1, and the overflowed cleaning liquid 15 is received by the outer tank 3. By returning the cleaning liquid 15 to the cleaning tank 1 via the filter 9 by the circulation pump 7, the cleaning liquid 15 filtered by the filter 9 is constantly circulated in the cleaning tank 1. Then, the wafer W is placed in the cleaning tank 1.
By immersion, dirt such as particles and organic substances adhered to the surface of the wafer W could be removed.

[0005]

However, in the overflow type cleaning apparatus 13 described above, the cleaning liquid 15 is used.
Flows upward from below the washing tank 1,
When a hydrophobic wafer is acid-cleaned using a cleaning liquid mixed with a hydrogen peroxide solution, bubbles generated in the cleaning liquid float upward from below the cleaning tank 1, and foreign matters floating along with the bubbles adhere to the wafer. There was a problem. Also, the cleaning solution 15
The foreign matter heavier than the specific gravity does not overflow from the cleaning tank 1 to the outer tank 3 depending on the flow of the cleaning liquid 15, stays in the stagnation at the bottom of the cleaning tank, and causes reattachment to the wafer. Was included. SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a wafer cleaning apparatus capable of eliminating air bubbles from adhering to a wafer and preventing foreign substances having a higher specific gravity than the cleaning liquid from remaining at the bottom of the cleaning tank. It is intended for.

[0006]

According to a first aspect of the present invention, there is provided a wafer cleaning apparatus, comprising: a cleaning tank; a drain port provided at a bottom of the cleaning tank; An outer tank provided to allow the washing liquid to overflow to the washing tank, a circulation pipe communicating the drainage port with the outer tank, and a circulation pump and a filter sequentially interposed in the circulation pipe. It is assumed that. In addition, the wafer cleaning apparatus includes a first cleaning tank, a liquid supply port provided at a bottom of the first cleaning tank, an outer tank that receives a cleaning liquid that overflows from the first cleaning tank, and a cleaning liquid that overflows from the outer tank. Receiving a second cleaning tank, a drain port provided at the bottom of the second cleaning tank, a circulation pipe for communicating the liquid supply port with the drain port, and a circulation pump sequentially interposed in the circulation pipe And a filter.

According to the first aspect of the present invention, the cleaning liquid flows downward from above in the cleaning tank, and foreign matters heavier than the specific gravity of the cleaning liquid are discharged from the drain port of the cleaning tank and captured by the filter. . Further, when the cleaning liquid overflows from the outer tank to the cleaning tank, bubbles generated by the cleaning liquid float on the surface of the cleaning liquid due to buoyancy and escape to the atmosphere. As a result, in the cleaning tank, only the cleaning liquid from which bubbles have been removed comes into contact with the wafer. Further, in the wafer cleaning apparatus according to the second aspect, the cleaning liquid flows upward from below in the first cleaning tank, and flows downward from above in the second cleaning tank. For this reason, in the first cleaning tank, foreign substances having a specific gravity lower than the specific gravity of the cleaning liquid are removed, and in the second cleaning tank, foreign substances having a specific gravity higher than the specific gravity of the cleaning liquid are discharged from the drain port and captured by the filter. In addition, bubbles generated in the cleaning liquid are removed when the cleaning liquid overflows from the first cleaning tank to the second cleaning tank.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a wafer cleaning apparatus according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a first embodiment of a wafer cleaning apparatus according to the present invention. A funnel-shaped bottom portion 23 is formed at a lower portion of the cleaning tank 21 having an open upper surface, and a center of the bottom portion 23 is a drainage port 25. In this embodiment, a drain guide 29 is provided on the surface of the bottom 23. The drain guide 29 has an upper surface 31 formed in a mortar shape, and has a central drain outlet 33 communicating with the drain outlet 25 at the center of the upper surface, and also has a drain outlet at the edge of the upper surface 31. A plurality of outer liquid discharge ports 35 communicating with the outer liquid discharge port 25 are opened.

As described above, in the cleaning tank 21 provided with the drain guide 29, foreign matters having a higher specific gravity than the cleaning liquid are effectively guided from the edge and the center of the drain guide 29 to the drain outlet 25. This can prevent foreign matter from staying in the washing tank bottom 23. The bottom 23 of the cleaning tank 21
Can prevent foreign matters from being retained even by providing only the funnel-shaped inclined surface without providing the drainage guide portion 29.

[0010] A circulation pipe (drainage pipe) 37 is connected to the drainage port 25 of the washing tank 21, and the drainage pipe 37 is connected to a liquid supply port of a circulation pump 39. A filter 41 is connected to a discharge port of the circulation pump 39, and an outlet of the filter 41 is connected to a bottom surface of the outer tank 45 via a circulation pipe (liquid supply pipe) 43. The outer tub 45 is provided around the upper opening of the cleaning tub 21, and the outer peripheral wall 47 of the outer tub 45 is formed higher than the outer wall 21a of the cleaning tub 21 (in other words, the inner wall of the outer tub 45).

Next, the operation of the thus-configured cleaning apparatus 51 will be described. The cleaning tank 21 of the cleaning device 51 is filled with a mixed cleaning liquid 53 such as hydrochloric acid, hydrogen peroxide, and water. The wafer W is placed, for example, vertically (immersed) in the cleaning tank 21 with three points on its circumference fixed. Then, when the circulation pump 39 is driven, the cleaning liquid 53 is discharged from the bottom 2.
The liquid is sucked into the liquid discharge port 25 through the central liquid discharge port 33 and the external liquid discharge port 35 provided in the third liquid discharge guide portion 29.

The cleaning liquid 53 sucked into the drain 25 is
The water is supplied to the filter 41 by the circulation pump 39, passes through the filter 41, and is sent to the outer tank 45. The cleaning liquid 53 sent to the outer tank 45 has a water level in the outer tank 45 of the cleaning tank 21.
When it becomes higher than the outer wall 21a, it overflows from the outer wall 21a and flows into the cleaning tank 21. Cleaning tank 2
The washing liquid 53 flowing into the washing tank 1 flows downward from above in the washing tank 21, and is sucked again from the drain port 25 of the bottom 23, so that it is constantly filtered by the filter 41 and circulates in the washing tank 21. Becomes

In the cleaning device 51, since the cleaning liquid 53 flows downward from above in the cleaning tank 21, foreign matter heavier than the specific gravity of the cleaning liquid 53 is guided to the drain guide 29 of the cleaning tank 21. The liquid is discharged from the drain port 25. Then, the foreign matter discharged from the drain port 25 is captured by the filter 41 when passing through the filter 41.

In particular, bubbles are generated in the cleaning liquid 53 mixed with the hydrogen peroxide solution. When the cleaning liquid 53 overflows from the outer tank 45 to the cleaning tank 21, the bubbles rise to the surface of the cleaning liquid by buoyancy immediately after the overflow. It is not released into the atmosphere and does not enter deeply into the cleaning tank 21 (wafer immersion position). That is, in the cleaning tank 21, only the cleaning liquid 53 from which bubbles have been removed comes into contact with the wafer W.

As described above, according to the cleaning device 51 described above,
An outer tank 45 is provided on the outer periphery of the cleaning tank 21, and the cleaning liquid 53 supplied to the outer tank 45 is supplied to the cleaning tank 21 by overflowing, so that bubbles generated in the cleaning liquid 53 flow from the outer tank 45 to the cleaning tank 21. When overflow occurs, it floats on the surface of the cleaning liquid and is removed from the cleaning liquid 53. As a result, in the cleaning tank 21, only the cleaning liquid 53 from which bubbles have been removed can be brought into contact with the wafer W, and foreign substances can be prevented from adhering to the wafer W due to the contact of bubbles.

The drain port 25 is connected to the bottom 23 of the cleaning tank 21.
The cleaning liquid 53 that overflows from the upper opening of the cleaning tank 21 is drained from the drain port 25 of the bottom 23, so that the cleaning liquid 53 flows downward from above in the cleaning tank 21. Foreign matter heavier than the specific gravity can be quickly discharged from the drain port 25 and captured by the filter 41. As a result, the foreign matter having a high specific gravity does not stay in the stagnation at the bottom of the cleaning tank, and reattachment to the wafer can be prevented.

Next, a second embodiment of the wafer cleaning apparatus according to the present invention will be described with reference to FIG. FIG. 2 is a schematic configuration diagram showing a second embodiment of the wafer cleaning apparatus according to the present invention. The cleaning device 61 includes a first cleaning tank 6 having an open upper surface.
3 and the second cleaning tank 65 are integrated, and the peripheral wall 67 of the first cleaning tank 63 is formed higher than the peripheral wall 69 of the second cleaning tank 65. Further, an outer tank 71 is provided on the outer periphery of the upper surface opening of the first washing tank 63 and the second washing tank 65, and a peripheral wall 73 of the outer tank 71 is substantially equal to or larger than the peripheral wall 67 of the first washing tank 63. Formed at height.

The lower part of the second washing tank 65 has a funnel-shaped bottom 7.
5 is formed, and a drain port 25 is provided at the center of the bottom part 75. A circulation pipe (drain pipe) 37 is connected to the drain port 25, and the drain pipe 37 is connected to a supply port of a circulation pump 39. A filter 41 is connected to a discharge port of the circulation pump 39, and an outlet of the filter 41 is connected to a liquid supply port 79 provided at a bottom 77 of the first cleaning tank 63 via a circulation pipe (liquid supply pipe) 43. It is.

Next, the operation of the cleaning device 61 thus configured will be described. In the first cleaning tank 63 and the second cleaning tank 65, for example, a mixed cleaning liquid 5 such as hydrochloric acid, hydrogen peroxide, and water is used.
3 is satisfied. In each of the cleaning tanks 63 and 65, for example, the wafer W is immersed in a vertically placed shape with its circumference fixed. When the circulation pump 39 is driven, the cleaning liquid 53
Flows into the first cleaning tank 63 from the liquid supply port 79 of the first cleaning tank 63, and overflows from the upper opening of the first cleaning tank 63. Cleaning liquid 5 overflowing from first cleaning tank 63
3 flows directly into the second cleaning tank 65 or flows into the second cleaning tank 65 via the outer tank 71, and is sucked into the drain port 25 provided at the bottom 75 of the second cleaning tank 65.

The cleaning liquid 53 sucked into the drain 25 is
The water is supplied to the filter 41 by the circulation pump 39, passes through the filter 41, and is again supplied to the liquid supply port 79 of the first cleaning tank 63. The tank 65 is circulated.

In the cleaning device 61, the cleaning liquid 53 flows upward from below in the first cleaning tank 63, and flows downward from above in the second cleaning tank 65. From this,
In the first cleaning tank 63, foreign substances lighter than the specific gravity of the cleaning liquid 53 are removed, and in the second cleaning tank 65, foreign substances heavier than the specific gravity of the cleaning liquid 53 are discharged from the drain port 25 and captured by the filter 41. . In addition, when the cleaning liquid 53 overflows from the first cleaning tank 63 to the second cleaning tank 65, the bubbles generated in the cleaning liquid 53 are lifted to the surface of the cleaning liquid by buoyancy and escaped to the atmosphere, so that they are removed. .

As described above, according to the cleaning device 61 described above,
The first cleaning tank 63 and the second cleaning tank 65 are integrated, and the cleaning liquid 53 overflowed from the first cleaning tank 63 is drained from the bottom 75 of the second cleaning tank 65, passes through the filter 41, and is again discharged. Since the liquid is supplied from the bottom 77 of the first cleaning tank 63, air bubbles can be removed by overflow, and in the first cleaning tank 63 in which the cleaning liquid 53 flows upward from below, foreign matter having a low specific gravity can be removed. The second cleaning tank 6 53 flows downward from above.
In 5, the foreign matter having a high specific gravity can be removed.

Therefore, according to the cleaning device 61, the wafer W is first immersed in the second cleaning tank 65, whereby foreign matter having a high specific gravity is settled and removed by the downward liquid flow, and the foreign matter is removed by the filter 41. By capturing, and then immersing the wafer W in the first cleaning tank 63, the foreign matter having a low specific gravity can be removed by floating by an upward liquid flow, and the foreign matter can be removed by overflow. In addition, it is possible to reliably prevent particles from adhering to the wafer W when immersing in the cleaning tank.

In the cleaning apparatus 61 according to the second embodiment, the cleaning liquid 53 overflowing from the first cleaning tank 63 flows directly into the second cleaning tank 65 or passes through the outer tank 71 to the second cleaning tank 65. Although the flow is made to flow into the cleaning tank 65, the overflow from the first cleaning tank 63 to the second cleaning tank 65 may be performed only via the outer tank 71. In this case, by providing a filter (not shown) for capturing foreign matter having a lighter specific gravity than the cleaning liquid 53 in the outer tank 71, foreign matter overflowing from the first cleaning tank 63 due to overflow is captured by this filter, and the foreign matter having a lighter specific gravity is captured by the filter. It is possible to prevent the inflow into the second washing tank 65.

In the cleaning apparatuses 51 and 61 according to the first and second embodiments described above, the wafer is placed vertically and immersed in the liquid. However, it is also possible to perform cleaning by placing the wafer horizontally (horizontally). Although the above two embodiments have been described by taking as an example the case where the present invention is applied to a chemical cleaning apparatus, the cleaning apparatus according to the present invention has the same effect when applied to an ultrasonic cleaning apparatus using pure water.

[0026]

As described above in detail, according to the wafer cleaning apparatus of the first aspect, the outer tank is provided on the outer periphery of the cleaning tank, and the cleaning liquid supplied to the outer tank overflows and is supplied to the cleaning tank. Thus, when the cleaning liquid overflows to the cleaning tank, bubbles rise to the surface of the cleaning liquid and are removed from the cleaning liquid. As a result, only the cleaning liquid from which the bubbles have been removed can be brought into contact with the wafer, and the adhesion of foreign substances to the wafer caused by the contact of the bubbles can be prevented. Further, the cleaning liquid flows downward from above in the cleaning tank, so that foreign substances heavier than the specific gravity of the cleaning liquid can be captured by the filter. As a result, the foreign matter having a high specific gravity does not stay in the stagnation at the bottom of the cleaning tank, and reattachment to the wafer can be prevented. Claim 2
According to the wafer cleaning apparatus according to the first cleaning tank and the second cleaning tank are integrated, the cleaning liquid overflowed from the first cleaning tank is drained from the bottom of the second cleaning tank and passed through the filter. Again from the bottom of the first cleaning tank, so that air bubbles can be removed by overflow, and in the first cleaning tank in which the cleaning liquid flows upward from below, foreign substances having a low specific gravity can be removed, and the cleaning liquid can be removed upward. In the second washing tank that flows downward from above, foreign matter having a high specific gravity can be removed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of a wafer cleaning apparatus according to the present invention.

FIG. 2 is a schematic configuration diagram showing a second embodiment of the wafer cleaning apparatus according to the present invention.

FIG. 3 is a schematic configuration diagram showing a conventional wafer cleaning apparatus.

[Explanation of symbols]

 Reference Signs List 21 cleaning tank 23, 75, 77 bottom 25 drain port 37, 43 circulation pipe 39 circulation pump 41 filter 45, 71 outer tank 51, 61 wafer cleaning device 53 cleaning liquid 63 first cleaning tank 65 second cleaning tank 79 liquid supply port

Claims (3)

[Claims] A cleaning tank; a drain port provided at a bottom of the cleaning tank; an outer tank provided at an outer periphery of an upper surface opening of the cleaning tank to overflow a cleaning liquid into the cleaning tank; A wafer cleaning apparatus, comprising: a circulation pipe communicating with the outer tank; and a circulation pump and a filter sequentially interposed in the circulation pipe. 2. A first cleaning tank, a liquid supply port provided at a bottom portion of the first cleaning tank, an outer tank receiving a cleaning liquid overflowing from the first cleaning tank, and receiving an overflowing cleaning liquid from the outer tank. A second cleaning tank, a drain port provided at the bottom of the second cleaning tank, a circulation pipe for communicating the liquid supply port with the drain port, and a circulation pump and a filter sequentially interposed in the circulation pipe A wafer cleaning apparatus comprising: 3. The wafer cleaning apparatus according to claim 2, wherein a filter for capturing foreign matter having a specific gravity lower than that of the cleaning liquid is provided in the outer tank.