JPH04343416A - Washing device - Google Patents

Abstract

PURPOSE:To provide a washing device with a washing capacity which is equivalent to that of a horizontal type washing device, especially an improved washing capacity at an inside of a gas-introduction capillary portion and a double capillary portion which a tube is equipped with, for a vertical type washing device which is optimum for washing of a crystal tube used in a so called vertical type furnace which performs heat treatment of a silicon wafer. CONSTITUTION:The title item is provided with the first supply path 67 and the first delivery path 73 for washing an inside of a chamber 52 of a tube 50 which is placed within a washing chamber 32, the second supply path 71 and the second delivery path 74 for washing an outside of the chamber, and further the third delivery path 81 for coping with an overflow of a washing liquid.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning apparatus most suitable for cleaning quartz tubes used in so-called vertical furnaces for heat-treating silicon wafers.

0002

2. Description of the Related Art Many quartz parts are used in furnaces for heat treating silicon wafers, and because the quartz parts become contaminated during this heat treatment process, it is necessary to periodically clean the quartz parts. Conventionally, there are two types of apparatus for cleaning quartz parts as described above: horizontal type and vertical type.

FIG. 4 is a schematic diagram showing an example of a horizontal quartz parts cleaning apparatus. This horizontal quartz parts cleaning device includes a pretreatment/drying tank 11, a cleaning tank 12, and a chemical solution tank 13.
A plurality of tanks such as the above are prepared, quartz parts such as the quartz tube 14 are placed on the hanger 15, and the hanger 15 moves in the directions of arrows A and B as well as in the vertical direction.
A quartz tube 14 or the like is housed in, for example, a pretreatment/drying tank 11, and dust is removed by, for example, blowing out a pure water shower.Then, it is immersed in a chemical solution 16 filled in a chemical solution tank 13, and then a cleaning solution 17 is applied. It is immersed in the cleaning liquid 17 in the overflowing cleaning tank 12, and then stored in the pretreatment/drying tank 11 and dried, for example, by blowing out air. Here, rollers 18 and 19 are provided in the cleaning tank 12 and the chemical solution tank 13, and the immersed quartz tube 14 may be rotated by these rollers 18 and 19 in order to enhance the cleaning effect.

[0004] The horizontal type quartz parts cleaning apparatus having the above structure has a high cleaning effect because the quartz parts such as quartz tubes are immersed in the liquid, but requires a large space because it is a multi-tank type apparatus. Further, if the outer shape of the quartz chamber 14 is not rotated, it cannot be rotated by the rollers 18 and 19, and no cleaning effect can be expected from this rotation. FIG. 5 is a schematic cross-sectional view showing an example of a conventional vertical quartz parts cleaning apparatus.

[0005] This vertical cleaning device includes a cleaning chamber 21,
A nozzle 22 that showers a chemical solution or cleaning liquid onto the inside of the quartz tube 14 housed in the cleaning chamber 21, a nozzle 23 that showers a chemical solution or cleaning liquid onto the outside of the quartz tube 14, and a nozzle 23 that showers the chemical solution or cleaning liquid onto the outside of the quartz tube 14. A drain 24 is provided for discharging the water to the outside. Since this vertical cleaning device is a one-chamber type, it has the advantage of being able to be installed in a smaller space compared to the horizontal cleaning device mentioned above.
Because it is a shower type, its cleaning ability is inferior to horizontal cleaning equipment, and its cleaning ability inside the gas introduction tube thin tube section and double tube section (not shown in Figure 5) provided in the quartz tube is extremely low. There are other problems.

[0006]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention provides a vertical cleaning device that can be installed in a narrow space, which has a cleaning capacity comparable to that of a horizontal cleaning device, and in particular, a vertical cleaning device that can be installed in a narrow space. It is an object of the present invention to provide a cleaning device with improved cleaning ability for the inside of a gas introduction thin tube section or a double tube section.

[0007]

[Means for Solving the Problems] To achieve the above object, a tube cleaning device of the present invention cleans a tube having a substantially cylindrical chamber opening downward, which is disposed in a furnace for heat-treating wafers. The apparatus includes a housing having a cleaning chamber therein, an inner chamber surrounded by a floor of the cleaning chamber and an inner wall of the chamber, and a wall surface of the cleaning chamber and an outer wall of the chamber. a first supply route for supplying cleaning liquid to the inner chamber in a cleaning state in which the tube is arranged with the opening facing downward so as to be divided into an enclosed outer chamber; and a first supply path for supplying cleaning liquid from the floor of the inner chamber a first discharge route for discharging the cleaning liquid; a second supply route for supplying the cleaning liquid to the outer chamber; a second discharge route for discharging the cleaning liquid from the floor of the outer chamber; and the cleaning of the outer chamber. The present invention is characterized by comprising a third discharge path for discharging the cleaning liquid from further above the upper end of the tube in this state.

[0008]Here, the above-mentioned "cleaning liquid" is not limited to a specific one, but is a concept that includes the chemical liquid in the conventional example described above, pure water for washing away this chemical liquid, etc., and multiple types of cleaning liquid can be supplied and discharged. It may be configured as follows. Furthermore, the above-mentioned "discharge" refers to discharge from the cleaning chamber, and also includes collecting and reusing the cleaning liquid discharged from the cleaning chamber.

[0009]

[Operation] The cleaning device of the present invention includes a first supply path and a first discharge path for cleaning the inside of the chamber of a tube arranged in the cleaning chamber, and a second supply path for cleaning the outside of the chamber. and a second discharge path, and the third discharge path for dealing with the overflow of the cleaning liquid. After filling the room with cleaning liquid, it is possible to perform a so-called quick dump rinse (QDR), in which the cleaning liquid is rapidly drained from the bottom, and as shown in the examples described later, it has a cleaning capacity that is almost the same as a horizontal cleaning device, and A cleaning device is realized that can sufficiently clean the inside of the gas introduction thin tube section and the double tube section, which are difficult to clean.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic external perspective view of a cleaning device according to an embodiment of the present invention, and FIG. 2 is a vertical sectional view showing the inside thereof. This cleaning device 30 is equipped with a sliding door 31 as shown in FIG. 1. After the quartz tube 50 is carried into the cleaning chamber 32, the sliding door 31 is closed and pressed against the packing 33. Handle 4 for closing the door
is engaged with the engaging portion 35, thereby maintaining the interior of the cleaning chamber 32 in a watertight structure.

As shown in FIG. 2, this quartz tube 50 has a substantially cylindrical chamber 52 that opens downward, and in a furnace, a silicon wafer is placed in this chamber 52 and heat-treated. The upper part of this chamber 52 is in communication with a gas introduction thin tube 52 through which gas is introduced for heat treatment, and this gas introduction thin tube 53 extends downward along the outside of the chamber 52. Further, the wall of this chamber 52 has a double pipe structure, and is provided with small holes 54 for gas inflow and outflow during heat treatment. Further, this chamber 52 has a hole 55 for venting the gas introduced into the chamber 52.
It has a flange 51 at its lower part.

Quartz tube 5 carried into cleaning chamber 32
0 is arranged so that the lower flange portion 51 is placed on a packing 36 made of a material that is not attacked by cleaning chemicals such as silicone rubber, and the flange portion 51 is held by a point contact type clamp 37. The quartz tube 50 is thereby fixed in the cleaning chamber 32. When the quartz tube 50 is arranged and fixed at a predetermined position in the cleaning chamber 32 in this way, the cleaning chamber 32 is roughly divided into a section surrounded by the floor 33 of the cleaning chamber 32 and the inner wall of the chamber 52. It is divided into an inner chamber 32a and an outer chamber 32b surrounded by the wall of the cleaning chamber 32 and the outer wall of the chamber 52.

The lower part of the cleaning chamber 32 is provided with a pure water tank 61 filled with pure water and a chemical tank 62 filled with cleaning chemicals. 64 and is supplied from the floor surface of the interior chamber 32a via a three-way valve 65. In this embodiment, these tanks 61, 62, pumps 63, 64,
The three-way valve 65 and the pipe 66 connecting them constitute a first supply path 67 according to the present invention. Further, the pure water and chemical liquid in the pure water tank 61 and the chemical liquid tank 62 are also sucked up by pumps 68 and 69, respectively, and are supplied from the floor of the outer chamber 32b via the three-way valve 70. In this embodiment, a second supply path 72 is formed by these tanks 61, 62, pumps 68, 69, three-way valve 70, and a pipe 71 connecting them.

Further, pipes 75 and 76 constituting a first discharge path 73 and a second discharge path 74 are arranged on the floor surfaces of the inner chamber 32a and the outer chamber 32b, respectively.
, 74 are discharged through valves 77 and 78, respectively, as a used chemical solution or as general wastewater. Additionally, a third discharge path 8 for overflow is provided in the upper part of the cleaning chamber 32.
A pipe 82 constituting the cleaning chamber 32 is connected to the cleaning chamber 32.
When the inside is full of pure water or chemical solution, use this pipe 8.
1. Reusable chemical liquids are collected in the chemical liquid tank 82 via the three-way valve 79, and used chemical liquids or pure water are discharged. The cleaning chamber 32 is also provided with a nozzle 83 for shower cleaning.

Since the tube cleaning device 30 of this embodiment is constructed as described above, for example, when the motor 64 is rotated with the valves 77 and 78 closed and the three-way valve 65 switched to the chemical tank 62 side, the The inner chamber 3 via the first supply route 67
A chemical solution is supplied to 2a, and the chemical solution also leaks from the hole 55 of the quartz tube 50, but it also fills the inner chamber 32a and flows through the gas introduction thin tube 53, thereby cleaning the inner wall of the gas introduction thin tube 53. be done. In addition, after filling the cleaning chamber 32 with the chemical liquid, the three-way valve 79 is switched to the chemical liquid tank 62 side, and the valves 77 and 78 are opened to collect the chemical liquid from the cleaning chamber 32. 5
6 is also washed.

In this manner, the cleaning device 30 is of a one-chamber type, and moreover, the inner wall of the gas introduction capillary tube 53 and the inner wall 56 of the double tube of the quartz tube 50, which are difficult to clean, are also cleaned. FIG. 3 is a graph showing cleaning performance comparison data. A, B, and C in the figures are data for the horizontal cleaning device shown in FIG. 4, the vertical shower type cleaning device shown in FIG. 5, and the cleaning device according to an embodiment of the present invention shown in FIG. 2, respectively.

[0017] First, a vertical heat treatment furnace (not shown) is used.
Fifty 6-inch diameter silicon wafers whose surfaces were contaminated with Cu at a concentration of 1013 atms/cm2 were placed in a vertical quartz tube 50 (see Fig. 2) held in the quartz tube 50 (see Fig. 2), and heated in dry O2 at 1000°C. After 30 consecutive heat treatments for 1 hour, the quartz tube 50
is removed from the heat treatment furnace and cleaned with each cleaning device according to the sequence below, and then the inner wall 56 of the double tube (Fig. 2
The amount of Cu contained in the etching solution was measured when the portion (see ) was etched by about 1 μm with a hydrofluoric acid (HF) solution. Therefore, the lower the amount of Cu, the higher the cleaning effect in the cleaning device. Note that the reason why the inner wall 56 of the double tube becomes contaminated is because Cu attached to the inner wall of the chamber 52 diffuses through the quartz wall and reaches the inner wall 56 of the double tube.

In the horizontal cleaning device (A), the quartz tube 50 contaminated with Cu as described above is (1) immersed in the cleaning tank 12 (see FIG. 9) filled with pure water, and It was held for 10 minutes while being allowed to overflow, (2) it was then immersed in a chemical tank 13 filled with 5% HF solution and held for 30 minutes, and (3) it was then immersed in the cleaning tank 12 again to allow pure water to overflow. The condition was maintained for 15 minutes.

Further, in the vertical shower type cleaning device (B), the quartz tube 50 contaminated with Cu as described above is used.
(1) Pre-wash shower with pure water for 10 minutes, (2)
After that, shower with 15% HF solution for 10 minutes, (3)
After that, I took a shower with pure water for 20 minutes.

[0020] Furthermore, a cleaning device (
In C), the quartz tube 50 contaminated with Cu as described above is (1) prewashed with pure water for 5 minutes,
(2) The inside of the cleaning chamber 32 is filled with pure water and kept in a state where the pure water overflows for 10 minutes, (3) The inside of the cleaning chamber 32 is then kept in a state filled with 5% HF solution, (4)
) After that, a state in which pure water overflowed was maintained for 15 minutes.

After cleaning according to each of the above sequences, the amount of Cu contained in the etching solution (HF solution) after etching the inner wall 56 of the double tube with HF solution was measured, as shown in FIG. As shown in the figure, the cleaning device (C) according to the present invention exhibited a cleaning power comparable to or exceeding that of the horizontal cleaning device (A).

[0022]

Effects of the Invention As described above in detail, the cleaning device of the present invention has a first supply route, a first discharge route, a second supply route, and a second discharge route corresponding to the inside and outside of the chamber. Since the cleaning device is provided with a cleaning path and is further provided with a third discharge path for overflow, a one-chamber type cleaning device with high cleaning ability is realized.

[Brief explanation of drawings]

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

FIG. 2 is a longitudinal sectional view showing the internal structure of the cleaning device whose appearance is shown in FIG. 1;

FIG. 3 is a graph showing cleaning performance comparison data.

FIG. 4 is a schematic configuration diagram showing an example of a horizontal quartz parts cleaning apparatus.

FIG. 5 is a schematic cross-sectional view showing an example of a conventional vertical quartz parts cleaning apparatus.

[Explanation of symbols]

30 Tube cleaning device
32 Cleaning chamber 32a Inner chamber
32b Outer room 33 Floor
50 Quartz tube 67 First supply route
71 Second supply route 73 First discharge route
74 Second discharge route 81 Third discharge route

Claims (1)

[Claims] Claim 1: Disposed in a furnace for heat-treating wafers;
A cleaning device for cleaning a tube having a substantially cylindrical chamber opening downward, the housing having a cleaning chamber inside, the cleaning chamber being surrounded by a floor of the cleaning chamber and an inner wall of the chamber. In a cleaning state in which the tube is arranged with the opening facing downward so as to be divided into an inner chamber and an outer chamber surrounded by a wall surface of the cleaning chamber and an outer wall of the chamber, a cleaning liquid is added to the inner chamber. a first supply route for discharging the cleaning solution from the floor of the inner chamber, a second supply route for discharging the cleaning solution from the floor of the outer chamber, and a second supply route for discharging the cleaning solution from the floor of the outer chamber. A cleaning device comprising: a second discharge path for discharging the liquid; and a third discharge path for discharging the cleaning liquid from above the upper end of the tube in the cleaning state of the outer chamber.