JP2001106595A - Device for cleaning and drying silicon raw material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continuously and easily clean a silicon raw material and to obtain the silicon raw material low in contamination caused by fine particles. SOLUTION: This device for cleaning and drying a silicon raw material is preferably equipped with a liquid-permeable endless belt 12 for carrying a powdery or lumpy silicon raw material 11, a hopper 13 for supplying the silicon raw material to the belt 12, a cleaning solution spraying device 14 for spraying a cleaning solution 18 onto the silicon raw material 11 on the belt to clean the silicon raw material 11, an ultrapure water spraying device 16 for spraying ultrapure water onto the silicon raw material to wash off the cleaning solution 18 stuck on the silicon raw material 11 and a drier 17 for blowing warm air to the silicon raw material to dry the silicon raw material. It is possible to constitute the belt 12 with a first belt, a second belt and a third belt. It is preferable that a liquid bath 21 is provided oppositely to the cleaning solution spraying device 14, and a water collecting bath 28 is provided oppositely to the ultrapure water spraying device 16, and further the ultrapure water spraying device 16 is constituted of a first spraying device 26 and a second spraying device 27.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for cleaning and drying massive or granular polycrystalline silicon (polysilicon), which is a raw material for producing a silicon single crystal by the Czochralski method, and single crystal silicon. is there.

[0002]

2. Description of the Related Art A silicon single crystal for a semiconductor device is manufactured mainly by a Czochralski method (hereinafter, referred to as a CZ method). In the CZ method, a bulk or granular silicon material such as polycrystalline silicon or single crystal silicon is melted in a quartz crucible in a furnace, a seed crystal is immersed in the obtained melt, and the seed crystal is pulled up to obtain a silicon single crystal. This is a method of growing crystals. Single-crystal silicon that could not be pulled as desired by the CZ method can also be a silicon raw material of the present invention. Since a silicon raw material such as polycrystalline silicon or single crystal silicon has an active property, it is put in a plastic bag and sealed until it is put into a quartz crucible. However, before and after sealing, an oxide film is easily formed on the surface of the silicon raw material by reacting with oxygen in the air. The oxide film is formed to include organic substances, fine particles, or metal impurities attached to the surface of the silicon raw material, or organic substances, fine particles, or metal impurities adhere to the surface of the oxide film after the oxide film is formed. Of these, the silicon raw material is placed in a quartz crucible with fine particles attached, and when melted, CZ
There is a problem that the dislocation-free growth of the silicon single crystal produced by the method is hindered, and the so-called free rate (the rate at which dislocation-free single-crystal silicon is obtained from a silicon raw material) is reduced.

In order to solve this problem, conventionally, a silicon raw material is put into a basket before being put into a quartz crucible, and this basket is immersed in a washing tank containing a mixed acid of hydrofluoric acid and nitric acid, and then pulled up. The silicon raw material is washed by immersing the basket in a rinsing tank containing ultrapure water and pulling it up. When the basket containing the silicon material is repeatedly used in this conventional cleaning method and immersed in the cleaning tank, fine particles accumulate in the cleaning liquid, and the cleaning effect of the silicon raw material is reduced. After regularly replenishing a new cleaning solution and cleaning a predetermined amount of silicon material,
All cleaning solutions have been replaced with new cleaning solutions.

[0004]

However, immersing a silicon raw material in a basket, immersing it in a cleaning tank, pulling it up, and then immersing the basket in a rinsing tank and pulling up the silicon raw material involves continuously treating the silicon raw material. When washing a relatively large amount of silicon raw material, the immersion, pulling up operation, replacement of the silicon raw material into a basket, and the like have to be repeatedly performed, which is relatively difficult. Also, according to the above-described method, before the silicon material is repeatedly cleaned and replaced with a new solution, the concentration of the fine particles increases, and there is a problem that the free ratio is reduced as described above. An object of the present invention is to provide an apparatus for cleaning and drying a silicon raw material that can continuously and relatively easily clean the silicon raw material. Another object of the present invention is to provide an apparatus for cleaning and drying a silicon raw material, which increases the free ratio.

[0005]

The invention according to claim 1 is
As shown in FIG. 1, a liquid-permeable endless belt 12 for transporting a granular or massive silicon raw material 11, a silicon raw material 11 provided above an upstream end of the belt 12 and storing the silicon raw material 11, and supplying the silicon raw material 11 to the belt 12. A cleaning liquid ejecting device 14 provided above the belt 12 on the downstream side of the hopper 13 to inject the cleaning liquid 18 onto the silicon raw material 11 on the belt 12 to clean the silicon raw material 11; An ultrapure water injection device 16 provided above the side belt 12 to inject ultrapure water 19 onto the silicon raw material 11 on the belt 12 to wash off the cleaning liquid 18 attached to the silicon raw material 11; A drying device 17 provided above the downstream end of the belt 12 on the further downstream side and drying the silicon raw material 11 by irradiating the silicon raw material 11 on the belt 12 with hot air. A cleaning and drying apparatus of the silicon material having a.

In the invention according to the first aspect, the belt 12
Raw material 11 supplied from the hopper 13 on the upstream side of
Is washed and dried while reaching the downstream end of the belt 12. As a result, the silicon raw material can be continuously cleaned. Examples of the cleaning liquid 18 for the silicon raw material include a mixed solution of hydrofluoric acid and nitric acid, and a mixed solution of hydrofluoric acid and a dissolved ozone aqueous solution. By using hydrofluoric acid and nitric acid for the cleaning liquid, cleaning for a relatively short time is possible, and by using hydrofluoric acid and an aqueous solution of dissolved ozone, it is possible to use a high-purity cleaning liquid. It is possible to remove fine particles, impurities and the like attached to the surface.

The invention according to claim 5 is, as shown in FIG. 2, provided with a liquid-permeable endless first belt 51 for transporting a granular or massive silicon raw material 11 and an upper end above the upstream end of the first belt 51. And the first belt 5 for storing the silicon raw material 11
A hopper 13 that supplies the silicon raw material 11 to the first belt 1 and a first belt 51 that is provided above the first belt 51 downstream of the hopper 13.
A cleaning liquid spraying device 14 for spraying the cleaning liquid 18 onto the silicon raw material 11 on the belt 51 to clean the silicon raw material 11;
A liquid-permeable endless second belt 52 provided below the downstream end of the first belt 51 and transporting the cleaned silicon raw material 11.
An ultrapure water injection device 16 provided above the second belt 52 for injecting ultrapure water 19 onto the silicon raw material 11 on the second belt 52 to wash off the cleaning liquid 18 attached to the silicon raw material 11; A liquid-permeable endless third belt 53 provided below the downstream end of the belt 52 for conveying the silicon raw material 11 from which the cleaning liquid 18 has been washed off, and a silicon raw material 11 on the belt 53 provided above the third belt 53 A drying apparatus 17 for drying the silicon raw material 11 by irradiating warm air thereto.

In the invention according to claim 5, the silicon raw material 11 supplied from the hopper 13 to the upstream side of the first belt 51 is washed while reaching the downstream end of the third belt 53,
It can be rinsed and dried to continuously clean the silicon raw material. In particular, the first, second and third belts 51, on which the silicon raw material 11 is loaded and moved
Since the belts are constituted by the belts 52 and 53, the degree of freedom in arranging the respective belts is increased, which is effective when it is difficult to arrange the single belt according to claim 1 straight.

The invention according to a second aspect is the invention according to the first aspect, wherein the belt 12 faces the cleaning liquid ejecting device 14.
And a liquid tank 21 that collects and stores the cleaning liquid 18 that has passed through the belt 12, and receives the ultrapure water 19 that has been provided below the belt 12 and that has passed through the belt 12 so as to face the ultrapure water injection device 16. This is a cleaning and drying apparatus for silicon raw materials further including a water collecting tank 28. The invention according to claim 6 is the invention according to claim 5, wherein the liquid tank is provided below the first belt 51 so as to face the cleaning liquid ejecting device 14, and collects and stores the cleaning liquid passing through the first belt 51. 21 and a water collecting tank 28 provided below the second belt 52 so as to face the ultrapure water injection device 16 and receive the ultrapure water 19 passing through the second belt 52.
And a device for cleaning and drying a silicon raw material. According to the second and sixth aspects of the present invention, the cleaning liquid 18 and ultrapure water can be recovered, so that they can be prevented from being scattered, and the cleaning liquid and the like can be effectively used.

[0010] The invention according to claim 3 is the invention according to claim 1 or 2, wherein the ultrapure water injection device 16 is provided on the hopper side and the first injection device 26 is provided on the drying device side. And the temperature of the ultrapure water of the first injector 26 is 25 to 50 ° C., and the temperature of the ultrapure water of the second injector 27 is higher than the temperature of the ultrapure water of the first injector 26. 50-9
This is a washing and drying apparatus for silicon raw materials at 0 ° C. The invention according to claim 7 is the invention according to claim 5 or 6,
The liquid-permeable endless main belt 52d provided below the downstream end of the first belt 51 with the second belt 52 and the liquid-permeable endless auxiliary belt 52 provided below the downstream end of the main belt 52d.
e below the downstream end of the auxiliary belt 52e.
A belt 53 is provided, and the ultrapure water injection device 16 includes a first injection device 26 provided above the main belt 52d and a second injection device 27 provided above the auxiliary belt 52e. Cleaning and drying of a silicon raw material in which the temperature of the ultrapure water at 26 is 25 to 50 ° C and the temperature of the ultrapure water of the second injection device 27 is 50 to 90 ° C, which is higher than the ultrapure water of the first injection device 26 Device.

According to the third and seventh aspects of the present invention, the ultra-pure water is sprayed by the first and second spraying devices 26 and 27 to wash off the cleaning liquid, so that the silicon raw material 1
The fine particles, impurities, and the like attached to the surface of No. 1 can be more efficiently removed. Further, by making the temperature of the ultrapure water of the second injection device 27 higher than the temperature of the ultrapure water of the first injection device 26, the so-called rinsing effect is improved, and the temperature of the silicon raw material 11 itself is increased. Drying of the silicon raw material 11 in the drying device 17 is facilitated. The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the cleaning liquid 18 provided in the discharge pipe 21a of the liquid tank 21 and the cleaning liquid 18 stored in the liquid tank 21 is injected through the feedback pipe 23. This is a silicon raw material washing / drying apparatus provided with a circulation pump 22 for jetting from an injection nozzle 14 of the apparatus, and a filter 24 provided in one or both of a discharge pipe 21a and a feedback pipe 23.

The invention according to claim 9 is the invention according to claims 5 to 8
The invention according to any of the above, wherein the discharge pipe 21a of the liquid tank 21
The cleaning liquid 18 stored in the liquid tank 21 is supplied to the injection nozzle 14 of the cleaning liquid injection device through a feedback pipe 23.
This is a washing and drying apparatus for a silicon raw material, comprising a circulation pump 22 for jetting from a nozzle and a filter 24 provided on one or both of the discharge pipe 21a and the feedback pipe 23. According to the fourth and ninth aspects of the present invention, crushed pieces of the silicon raw material are removed from the cleaning liquid 18 collected in the liquid tank 21 by the filter 24, and the filter 24 prevents fine particles from being deposited on the cleaning liquid 18. Thus, when single crystal silicon is grown from the silicon raw material cleaned by this apparatus, its free ratio is increased. If the filter 24 is provided in the discharge pipe 21a, the circulation pump 22
Since the filter 24 removes the fine particles from the cleaning liquid 18 sucked by the pump, the damage of the circulation pump 18 can be prevented.

The invention according to claim 8 is the invention according to claims 5 to 7
As shown in FIG. 2, the silicon raw material 11 arriving at the downstream ends of the belts 51, 52, 53
Material releasing means 54, 55, 56, 57 for preventing the toner from following the rear surfaces of the belts 51, 52, 53 are provided at or near the downstream ends of the first belt 51, the second belt 52, and the third belt 53, respectively. It is a washing and drying device for silicon raw materials. In the invention according to claim 8, when the belt on which the silicon raw material 11 is mounted and moved is constituted by the first, second and third belts 51, 52, 53, the belts 51, 52, 53 are formed on the back surfaces thereof. It is possible to effectively prevent the silicon raw material 11 from following.

[0014]

Embodiments of the present invention will now be described with reference to the drawings. As shown in FIG. 1, in this embodiment, an apparatus 10 for cleaning and drying a silicon raw material includes a liquid-permeable endless belt 12 for conveying a granular or massive silicon raw material 11, and a hopper for supplying the silicon raw material 11 to the belt 12. 13, a cleaning liquid spraying device 14 for cleaning the silicon raw material 11, an ultrapure water spraying device 16 for cleaning off the cleaning liquid adhered to the silicon raw material 11, and a drying device 17 for drying the silicon raw material 11. The belt 12 is a mesh having a mesh size of 0.5 mm made of chemical-resistant polytetrafluoroethylene (trade name: Teflon), and is formed by a cleaning liquid 18 sprayed by a cleaning liquid spraying device 14 and an ultrapure water spraying device 16. The jetted ultrapure water 19 is configured to be able to pass through. The belt 12 includes a driving roller 12a, a driven roller 12b, an auxiliary roller 12c, and a tension adjusting roller 1.
2d and a pair of folding rollers 12e and 12f, and are configured to be movable in a direction indicated by a solid arrow in FIG. 1 by rotation of the driving roller 12a.

The hopper 13 is a container provided with a valve 13a at a lower opening, and is provided above the upstream end of the belt 12. The hopper 13 is configured to be able to store the silicon raw material 11 and supply the silicon raw material 11 to the belt 12 by opening the valve 13a. The supplied silicon raw material 11 is spread in the width direction of the belt 12 by a scraper (not shown) so that the thickness of the raw material 11 becomes substantially uniform on the belt 12. Here, the thickness of the silicon raw material 11 is preferably about 3 to 8 mm.

The cleaning liquid spraying device 14 is provided above the belt 12 on the downstream side of the hopper 13, and cleans the silicon raw material 11 supplied onto the belt 12 from the hopper 13 with the cleaning liquid 18.
To clean the silicon raw material 11. The cleaning liquid ejecting apparatus 14 according to the present embodiment is configured such that the ejection port 14 a is provided with the silicon raw material 1 supplied on the belt 12.
A cleaning liquid jet nozzle provided above the belt 12 so as to face the belt 1, and the belt 1 facing the nozzle 14
2 is ejected by the nozzle 14 of the belt 1
A liquid tank 21 is provided for collecting and storing the cleaning liquid 18 that has passed through the cleaning liquid 18. A discharge port of a circulation pump 22 for pressure-feeding the cleaning liquid is connected to a cleaning liquid injection nozzle, which is the cleaning liquid injection device 14, via a feedback pipe 23, and a discharge pipe 21a of a liquid tank 21 is connected to a suction port of the circulation pump 22. You. The feedback tube 23 is provided with a filter 24. The circulating pump 22 is used for cleaning liquid 1 stored in the liquid tank 21.
8 is sucked through the discharge pipe 21a, and the feedback pipe 2
After passing through the filter 24 through the filter 3, the cleaning liquid injection device 14 is configured to inject the cleaning liquid injection nozzle 14 onto the silicon raw material 11 on the belt 12.

The ultrapure water injection device 16 includes the cleaning liquid injection device 1.
The belt 12 provided above the belt 12 downstream of
The cleaning liquid 18 attached to the silicon raw material 11 is washed off by spraying ultrapure water 19 onto the upper silicon raw material 11. The ultrapure water injection device 16 in this embodiment is
The first injection device 26 includes a first injection device 26 and a second injection device 27. The first injection device 26 is provided on the hopper 13 side.
The injection device 27 is provided on the drying device 17 side. The first and second injection devices 26 and 27 are respectively storage tanks 26a and 27a for storing ultrapure water 19, pumps 26b and 27b for pumping the ultrapure water 19, and pumped by the pumps 26b and 27b, respectively. Has pure water injection nozzles 26c and 27c capable of injecting the ultrapure water 19 in the storage tanks 26a and 27a onto the silicon raw material 11 on the belt 12, and each storage tank 26a and 27a has a pure water temperature controller (not shown). Are respectively provided. Each of the pure water temperature adjustment devices (not shown) adjusts the temperature of the ultrapure water 19 of the first injection device 26 to 25 to 50 ° C. and the temperature of the ultrapure water 19 of the second injection device 27 to the ultrapure water of the first injection device 26. 50-90 ° C higher than water 19
Respectively. In addition, below the belt 12 facing the ultrapure water injection device 16, water collecting tanks 28, 28 for receiving ultrapure water injected by the ultrapure water injection device 16 and passing through the belt 12 are provided, respectively. The ultrapure water received by the water tanks 28, 28 is configured to be drained thereafter.

The drying device 17 is provided above the downstream end of the belt 12 on the downstream side of the ultrapure water injection device 16.
The silicon raw material 11 is dried by applying hot air or hot air at 80 to 150 ° C. to the silicon raw material 11 above. The drying device 17 in this embodiment includes a blower 17 a having an air blowing pipe, a heater 17 b provided in the air blowing pipe, and a hot air nozzle for blowing air heated by the heater 17 b to the silicon raw material 11 on the belt 12. 17c. A crucible 29 for receiving the washed and dried silicon raw material 11 is provided below the drive roller 12 a, which is the downstream end of the belt 12.
Placed on top of

A method for cleaning the silicon raw material 11 using the cleaning / drying apparatus having such a configuration will be described. In this embodiment, a cleaning liquid 18 composed of a mixed acid of hydrofluoric acid and nitric acid is stored in a liquid tank 21 in advance, and the first and second injection devices 2 are stored.
Ultrapure water 1 is stored in each of storage tanks 26a and 27a.
9 are stored. The temperature of the ultrapure water of the first injection device 26 is adjusted to 25 to 50 ° C. by a pure water temperature controller (not shown), and the temperature of the ultrapure water of the second injection device 27 is higher than the ultrapure water of the first injection device. Is adjusted to 50 to 90 ° C. Scale 3
An empty crucible 29 is placed on 1. Next, the driving roller 12a is rotated to move the belt 12 in the direction of the solid line arrow in FIG. 1 at a speed of about 0.1 to 0.5 m / min, and the circulating pump 22 is operated to filter the cleaning liquid 18 in the liquid tank. After passing through 24, the cleaning liquid is injected from a cleaning liquid injection nozzle which is the cleaning liquid injection device 14. Also, the first injection device 2
6 and the pumps 26b and 27b of the second injection device 27 are operated to inject the ultrapure water 19 stored in the storage tanks 26a and 27a from the pure water injection nozzles 26c and 27c.

In this state, the valve 13a of the hopper 13 is opened, and the silicon raw material 11 such as lump polycrystalline silicon stored in the hopper 13 or lump of single crystal silicon that has not been subjected to the desired pulling by the CZ method is obtained. On the belt 12. Silicon raw material 11 supplied on belt 12
Moves with the movement of the belt 12 to move the cleaning liquid ejecting device 1
The cleaning liquid 18 is jetted by the cleaning liquid jetting device 14 in a state of being located below the cleaning liquid 18. When the cleaning liquid 18 is sprayed, first, fine crushed pieces of the silicon raw material 11 having a size of about 0.1 to 0.4 mm move to the liquid tank 21 together with the cleaning liquid 18 and are removed from the belt 12. Further, the oxide film formed on the surface of the silicon raw material 11 is removed by etching with the cleaning liquid 18, and fine particles or the like adhering to the oxide film or on the surface of the oxide film move to the liquid tank 21 together with the cleaning liquid 18 and the surface of the silicon raw material 11 Removed from The cleaning liquid 18 collected in the liquid tank 21 is filtered by the filter 24 when it is again fed to the cleaning liquid injection nozzle 14 by the circulation pump 22, and fine crushed pieces are collected by the filter 24. As a result, the cleaned cleaning liquid 18 without fine particles is jetted again from the cleaning liquid jet nozzle 14.

The silicon raw material 11 thus washed moves with the movement of the belt and is located below the ultrapure water injection device 16, and the ultrapure water 19 is injected by the ultrapure water injection device 16. . The ultrapure water 19 injected by the first injection device 26 passes between the bulk silicon raw materials 11 to wash away the cleaning liquid 18 and remaining fine particles and the like, and the high-temperature ultrapure water 19 injected by the second injection device 27 Is the first
Cleaning liquid 1 that could not be washed away with ultrapure water by the injection device 26
8 and the remaining fine particles are further washed away. By injecting ultrapure water with the first and second injection devices 26 and 27 to wash away the cleaning liquid, fine particles, impurities, and the like attached to the surface of the silicon raw material 11 can be more efficiently removed. Further, since the temperature of the ultrapure water of the second injection device 27 is higher than the temperature of the ultrapure water of the first injection device 26, the effect of so-called rinsing is improved, and the drying of the silicon raw material 11 in the drying device 17 can be performed later. It will be easier.

Thereafter, the silicon raw material 11 moves with the movement of the belt 12 and is dried by being blown with hot air while being positioned below the drying device 17, and falls by its own weight from the downstream end of the belt 12 to dry the silicon raw material 11. The raw material 11 is put in the crucible 29 and weighed by the measuring device 31. Although not shown, a predetermined weight of the silicon raw material 11 put in the crucible 29 is then put into the single crystal growing apparatus together with the crucible 29 and melted inside the single crystal growing apparatus.

Next, another embodiment of the present invention will be described. In the drawings, the same reference numerals as those of the above-described embodiment denote the same parts, and a repeated description will be omitted. As shown in FIG. 2, a cleaning and drying apparatus 50 for a silicon raw material in this embodiment includes a liquid-permeable endless first belt 51 that transports a granular or massive silicon raw material 11, and a downstream end of the first belt 51. A liquid-permeable endless second belt 52 provided below and transporting the silicon raw material 11 and a liquid-permeable endless third belt 53 provided below the downstream end of the second belt 52 and transporting the silicon raw material 11 are provided. Prepare. Each belt 51,5
Nos. 2, 53 have a mesh size of 0.1 made of chemically resistant polytetrafluoroethylene (trade name: Teflon).
The mesh is a 5 mm net, and is configured to be able to pass the cleaning liquid 18 injected by the cleaning liquid injection device 14 and the ultrapure water 19 injected by the ultrapure water injection device 16 respectively. These belts 51, 52, 53 are respectively driven rollers 51a,
52a, 53a, driven rollers 51b, 52b, 53b, and tension adjusting rollers 51c provided near the driving rollers.
The driving rollers 51a, 5c are stretched by 52c, 53c.
The silicon raw material 11 is mounted and movable by rotation of 2a and 53a.

Above the upstream end of the first belt 51, a silicon raw material 11 is stored, and
The cleaning liquid 18 is sprayed onto the silicon material 11 on the first belt 51 above the first belt 51 downstream of the hopper 13 to supply the silicon material 1.
1 is provided with a cleaning liquid injection device 14 for cleaning. The second belt 52 is configured to be capable of transporting the silicon raw material 11 cleaned by the cleaning liquid spraying device 14. Above the second belt 52, the ultrapure water 1 is added to the silicon raw material 11 on the second belt 52.
An ultrapure water injection device 16 is provided for injecting 9 and washing away the cleaning liquid 18 attached to the silicon raw material 11. The second belt 52 in this embodiment includes a liquid-permeable endless main belt 52d provided below the downstream end of the first belt 51,
A liquid-permeable endless auxiliary belt 52e is provided below the downstream end of the main belt 52d. Further, the ultrapure water injection device 16 includes a first injection device 26 provided above the main belt 52d and a second injection device 27 provided above the auxiliary belt 52e. The temperature of the pure water 19 is 25 to 50 ° C., and the temperature of the ultrapure water of the second injection device 27 is higher than that of the ultrapure water of the first injection device 26.
Adjusted to ~ 90 ° C.

The third belt 53 is provided below the downstream end of the second belt 52, that is, below the downstream end of the auxiliary belt 52e. The third belt 53 is configured to be able to transport the silicon raw material 11 rinsed by the ultrapure water jetting device 16. Above the third belt 53, the silicon raw material 11 on the third belt 53 is heated to 80 to 150 ° C. A drying device 17 is provided for drying the silicon raw material 11 with hot air or hot air. The first belt 5 faces the cleaning liquid ejecting device 14.
The cleaning liquid 18 passing through the first belt 51 is located below the cleaning belt 18.
A liquid tank 21 for collecting and storing the ultrapure water 19 is provided, and a water collecting tank 28 for receiving the ultrapure water 19 passing through the second belt 52 is provided below the second belt 52 so as to face the ultrapure water injection device 16. . The liquid tank 2 is connected to the discharge pipe 21a of the liquid tank 21.
A circulation pump 22 is provided for injecting the cleaning liquid 18 stored in 1 from a cleaning liquid injection nozzle 14 as a cleaning liquid injection device via a feedback pipe 23, and a filter 24 is provided in the feedback pipe 23.

The first belt 51 and the main belt 5 of the second belt
2d, the auxiliary belt 52e, and the downstream end of the third belt 53, at a downstream end of the silicon raw material 11, the raw material detaching means 54 for preventing the silicon raw material 11 arriving at the downstream end of the belt from following the back surfaces of the respective belts 51, 52a, 52b and 53. 55,5
6, 57 are provided. Each raw material separation means 54,
55, 56, 57 are drive rollers 51a, 52a, 53a
And the belts 51, 52a, 52b, and 53, which are stretched over the tension adjusting rollers 51c, 52c, and 53c. These raw material separation means 54, 55, 56, 5
Since 7 has the same structure, a description will be given below on behalf of the raw material separation means 54 provided at the downstream end of the first belt 51.

As shown in FIG. 3, the material separating means 54 has a separating nozzle 54a provided diagonally above the belt 51 stretched over the driving roller 51a and the tension adjusting roller 51c. The nozzle 54a is provided such that the injection port 54b faces the belt 51. This nozzle 54a is
It is connected via a connecting pipe 54c to the pure water injection nozzle 26c of the first injection device 26 provided above the main belt 52d of the belt. The ultrapure water 19 from the nozzle 54a
Is injected toward the first belt 51.

Returning to FIG. 2, the raw material separation means 54, 55,
Although 56 and 57 have the same structure, what is ejected from each of the separation nozzles 54a, 55a, 56a and 57a is different. That is, the ultrapure water 19 is jetted from the raw material separating means 54 provided at the downstream end of the first belt 51 and the raw material separating means 55 provided at the downstream end of the main belt 52d of the second belt. On the other hand, in the raw material separating means 56 provided at the downstream end of the auxiliary belt 52e and the raw material separating means 57 provided at the downstream end of the third belt 53, the hot air from the drying device 17 is injected.

The cleaning of the silicon raw material 11 using the cleaning / drying apparatus 50 having the above-described structure is carried out in advance.
8, and ultrapure water 19 is stored in the storage tanks 26a, 27a of the first and second injection devices 26, 27, respectively. Next, the driving rollers 51a of the respective belts 51, 52, 53,
The belts 12 are moved by rotating 52a and 53a. At the same time, the circulation pump 22 is operated to cause the cleaning liquid 18 in the liquid tank 21 to be injected from the cleaning liquid injection nozzle 14, and the ultrapure water 19 is injected by the first injection device 26 and the second injection device 27.

In this state, the valve 13 a of the hopper 13 is opened to supply the silicon raw material 11 onto the first belt 51. The silicon raw material 11 supplied onto the first belt 51 is supplied with the cleaning liquid 18 under the cleaning liquid ejecting device 14.
Is sprayed to clean the silicon raw material 11. The cleaned silicon raw material 11 drops from the downstream end of the first belt 51 to the upstream end of the second belt 52 by its own weight. The silicon raw material 11 moved to the second belt 52 is
The ultrapure water injection device 16 moves with the movement of the ultrapure water injection device 16 and the ultrapure water 1
9 is sprayed, and the cleaning liquid 18 attached to the silicon raw material is washed away. In this embodiment, the silicon material 11 on the main belt 52d of the second belt is injected with the ultrapure water 19 by the first injection device 26, and drops from the downstream end of the main belt 52d to the upstream end of the auxiliary belt 52e. Ultrapure water is injected into the silicon raw material 11 by the second injection device 27.

From the downstream end of the first belt 51 to the second belt 5
2, when falling to the upstream end of the main belt 52d, and when falling from the downstream end of the main belt 52d to the upstream end of the auxiliary belt 52e, the raw material separation means 54, 55 provided at each downstream end is The silicon raw material 11 is prevented from following the back surfaces of the respective belts 51 and 52a. Specifically, the silicon raw material 1 is placed on the back surface of the first belt 51.
When the first belt 5 follows, the ultrapure water 19 is supplied from the separation nozzle 54a obliquely above the folded first belt to the first belt 5
The silicon raw material 11 sprayed toward the first belt 51 and following the back surface of the first belt 51 is
The belt is separated from the belt 51 and moved onto the main belt 52d. Similarly, the silicon raw material 1 is placed on the back surface of the main belt 52d.
When the main belt 52d follows, the ultrapure water 19 is sprayed toward the main belt 52d from the separation nozzle 55a obliquely above the folded main belt 52d, and the silicon raw material 11 that has followed the back surface of the main belt 52d is superimposed. The jet of the pure water 19 separates the main belt 52d from the main belt 52d and moves the main belt 52d onto the auxiliary belt 52e.

After that, the silicon raw material 11 is
2e, falls from the downstream end to the upstream end of the third belt 53, moves with the movement of the third belt 53, and
7 is dried by blowing hot air on it, and falls by its own weight from the downstream end of the third belt 53. The dried silicon raw material 11 is put into the crucible 29 and weighed by the measuring device 31. The silicon material 11 having a predetermined weight placed in the crucible 29 is put into a single crystal growing apparatus together with the crucible 29 and then melted inside the single crystal growing apparatus. When dropping and moving from the downstream end of the auxiliary belt 52e to the upstream end of the third belt 53, and when dropping and moving from the downstream end of the third belt to the crucible 29, the raw material detaching means 56, 57 provided at each downstream end. This prevents the silicon raw material 11 from following the back surfaces of the respective belts 52e and 53.

Specifically, when the silicon raw material 11 follows the back surface of the auxiliary belt 52e, warm air is blown toward the auxiliary belt 52e from the separation nozzle 56a obliquely above the folded auxiliary belt 52e. Belt 52e
The silicon raw material 11 that has followed the back surface is separated from the auxiliary belt 52e by the injection of the warm air and is moved onto the third belt 53. Similarly, when the silicon raw material 11 follows the back surface of the third belt 53, warm air or hot air is injected from the separation nozzle 57 a above the folded third belt 53 toward the third belt 53, The silicon raw material 11 following the back surface of the belt 53 is separated from the third belt 53 by the injection of the warm air or the hot air, and
It is moved to. The other method of cleaning the silicon raw material 11 is the same as that of the above-described embodiment, and the description thereof will not be repeated.

In the above embodiment, a mixed acid of hydrofluoric acid and nitric acid is used as the cleaning liquid, but a mixed liquid of hydrofluoric acid and a dissolved ozone aqueous solution may be used as the cleaning liquid. The former mixed acid has the advantage that the etching rate is high and the cleaning time is short, but
The latter mixed solution can easily obtain high-purity hydrofluoric acid and an aqueous solution of dissolved ozone, and can increase the purity of the cleaning solution itself, thereby being excellent in the cleaning effect. In the above-described embodiment, the filter 24 is provided in the feedback pipe 23. However, the filter 24 may be provided in the discharge pipe 21a of the liquid tank 21, or may be provided in both the discharge pipe 21a and the feedback pipe 23. In the above embodiment, the bulk silicon raw material 1
Although 1 was used, it may be granular. Further, in the above-described another embodiment, the material separating means 54, 55, 56, 57 are provided at the downstream ends of the first belt 51, the second belt 52, and the third belt 53, respectively. 56,5
7 may be provided near the downstream ends of the first belt 51, the second belt 52, and the third belt 53, respectively.

[0035]

As described above, the washing and drying apparatus of the present invention comprises a liquid-permeable endless belt for conveying granular or massive silicon raw material, a hopper for supplying the silicon raw material to the belt, A cleaning liquid spraying device for spraying a cleaning liquid onto the silicon raw material to clean the silicon raw material, an ultrapure water spraying device for spraying ultrapure water onto the silicon raw material to wash away the cleaning liquid adhering to the silicon raw material, Since a drying device for drying the silicon raw material by blowing air is provided, the silicon raw material supplied from the hopper on the upstream side of the belt is washed and dried while reaching the downstream end of the belt. As a result, the silicon raw material can be continuously cleaned. Even if the belt is an apparatus composed of the first, second, and third belts, the silicon raw material can be continuously washed similarly. In particular, when the belts are constituted by the first, second, and third belts, the degree of freedom in arranging the respective belts increases, which is effective when it is difficult to arrange a single belt straight. In this case, if a raw material detaching means for preventing the silicon raw material from following the back surface of the belt is provided, the following can be prevented.

Further, if a liquid tank is provided below the belt opposite to the cleaning liquid injection device, and a water collecting tank is provided below the belt opposite to the ultrapure water injection device, the cleaning liquid and ultrapure water can be collected. Thus, they can be prevented from being scattered, and the cleaning liquid and the like can be effectively used. Further, if the ultrapure water injection device is configured by the first injection device and the second injection device,
Fine particles, impurities, and the like attached to the surface of the silicon raw material can be more efficiently removed. In this case, if the temperature of the ultrapure water of the second injection device is made higher than that of the ultrapure water of the first injection device, the so-called rinsing effect is improved, and the drying of the silicon raw material in the subsequent drying device becomes easy. .

Further, a circulating pump for injecting the cleaning liquid stored in the liquid tank from the injection nozzle of the cleaning liquid injection device through a feedback pipe is provided at the discharge pipe of the liquid tank, and either one or both of the discharge pipe and the feedback pipe are provided. If a filter is provided, the filter removes crushed pieces of silicon raw material from the cleaning liquid collected in the liquid tank to prevent fine particles from being deposited on the cleaning liquid. When bred, the free ratio can be increased. In addition, if a filter is provided in the discharge pipe, the filter removes the fine particles from the cleaning liquid sucked by the circulating pump, so that it is possible to prevent the circulating pump from being damaged.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an apparatus for cleaning and drying a silicon raw material according to the present invention.

FIG. 2 is a configuration diagram of another apparatus for cleaning and drying a silicon raw material according to the present invention.

FIG. 3 is an enlarged view showing a raw material detaching means of another washing and drying apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Silicon raw material 12 Belt 13 Hopper 14 Cleaning liquid injection device 16 Ultrapure water injection device 17 Drying device 18 Cleaning liquid 19 Ultrapure water 21 Liquid tank 21a Discharge pipe 22 Circulation pump 23 Feedback pipe 24 Filter 26 First injection device 27 Second injection device 28 Water collecting tank 51 First belt 52 Second belt 52d Main belt 52e Auxiliary belt 53 Third belt 54, 55, 56, 57 Material separation means

Claims (9)

[Claims] 1. A liquid-permeable endless belt (12) for conveying a granular or massive silicon raw material (11), and provided above an upstream end of the belt (12) for storing the silicon raw material (11); Silicon raw material (11) for the belt (12)
And a cleaning liquid (1) provided to the silicon raw material (11) on the belt (12) provided above the belt (12) downstream of the hopper (13).
A cleaning liquid ejecting device (14) for injecting the silicon material (11) by injecting the cleaning liquid (8); and a cleaning liquid ejecting device (14) provided above the belt (12) downstream of the cleaning liquid ejecting device (14). An ultrapure water injection device (16) for injecting ultrapure water (19) into the silicon raw material (11) to wash off the cleaning liquid (18) attached to the silicon raw material (11), and the ultrapure water injection device ( 16) a drying device (17) provided above the downstream end of the belt (12) on the downstream side of the belt (12) to dry the silicon raw material (11) by blowing hot air on the silicon raw material (11) on the belt (12); ) For cleaning and drying silicon raw materials. 2. A belt (1) facing a cleaning liquid injection device (14).
The cleaning liquid (1) provided below the belt (12) and provided under the belt (12)
8) and a liquid tank (21) for collecting and storing the same, and the belt (1) provided below the belt (12) so as to face the ultrapure water injection device (16).
The apparatus according to claim 1, further comprising a water collecting tank (28) for receiving the ultrapure water (19) passed through 2). 3. The ultrapure water injection device (16) includes a first injection device (26) provided on a hopper side and a second injection device (27) provided on a drying device side, wherein the first injection is performed. The temperature of the ultrapure water of the device (26) is 25 to 50 ° C, and the temperature of the ultrapure water of the second injection device (27) is higher than the temperature of the ultrapure water of the first injection device (26). The apparatus for cleaning and drying a silicon raw material according to claim 1, wherein the temperature is 90 ° C. 4. 4. A cleaning liquid (18) provided in a discharge pipe (21a) of a liquid tank (21) and stored in the liquid tank (21) through a feedback pipe (2).
A circulation pump (22) for injecting from the injection nozzle (14) of the cleaning liquid injection device via 3), and a filter (24) provided in one or both of the discharge pipe (21a) and the feedback pipe (23). The apparatus for cleaning and drying a silicon raw material according to any one of claims 1 to 3, further comprising: 5. A liquid-permeable endless first belt (51) for conveying a granular or massive silicon raw material (11), and said silicon raw material (11) provided above an upstream end of said first belt (51). ) And a hopper (13) for supplying a silicon raw material (11) to the first belt (51); and a hopper (13) provided above the first belt (51) downstream of the hopper (13). A cleaning liquid spraying device (14) for cleaning the silicon raw material (11) by spraying a cleaning liquid (18) onto the silicon raw material (11) on the belt (51); and a cleaning liquid jetting device (14) below the downstream end of the first belt (51). A liquid-permeable endless second belt (52) for conveying the washed silicon raw material (11); and a second belt (5) provided above the second belt (52).
2) an ultrapure water injection device (16) for injecting ultrapure water (19) to the upper silicon material (11) to wash off the cleaning liquid (18) attached to the silicon material (11); A liquid-permeable endless third belt (53) provided below the downstream end of (52) and transporting the silicon raw material (11) from which the cleaning liquid (18) has been washed away, and above the third belt (53) Hot air is applied to the silicon raw material (11) on the belt (53).
An apparatus for washing and drying silicon raw materials, comprising: a drying apparatus (17) for drying 1). 6. A liquid tank (21) provided below the first belt (51) opposite to the cleaning liquid injection device (14) for collecting and storing the cleaning liquid passing through the first belt (51). Pure water injection device (1
6) is provided below the second belt (52) so as to face the second belt (52).
The apparatus according to claim 5, further comprising a water collecting tank (28) for receiving the ultrapure water (19) passed through the belt (52). 7. A liquid-permeable endless main belt (52d) provided below a downstream end of the first belt (51) and a second belt (52) below a downstream end of the main belt (52d). A liquid-permeable endless auxiliary belt (52e) provided, wherein the auxiliary belt (52e)
A third belt (53) is provided below the downstream end of the main belt (52d). An ultrapure water injection device (16) is provided between the first injection device (26) provided above the main belt (52d) and the auxiliary belt (52e). A second injection device (27) provided above, and the first injection device (26).
The temperature of the ultrapure water is 25 to 50C, and the temperature of the ultrapure water of the second injection device (27) is 50 to 90C, which is higher than the ultrapure water of the first injection device (26). The apparatus for cleaning and drying a silicon raw material according to claim 5. 8. A material separation means (54, 55, 56, 54) for preventing the silicon material (11) arriving at the downstream end of the belt (51, 52, 53) from following the back surface of the belt (51, 52, 53). 57) is the first belt
The apparatus according to any one of claims 5 to 7, wherein the apparatus (51) is provided at or near the downstream end of the second belt (52) and the third belt (53). 9. A feedback pipe (2) provided in a discharge pipe (21a) of a liquid tank (21) and storing a cleaning liquid (18) stored in the liquid tank (21).
A circulation pump (22) for injecting from the injection nozzle (14) of the cleaning liquid injection device via 3), and a filter (24) provided on one or both of the discharge pipe (21a) and the feedback pipe (23) The apparatus for cleaning and drying a silicon raw material according to any one of claims 5 to 8, further comprising: