KR20160036138A - Method and apparatus for producing silicon - Google Patents

Abstract

The present invention relates to a method and an apparatus for manufacturing silicon. According to an embodiment of the present invention, the apparatus for manufacturing silicon comprises: a reactor having a reaction chamber therein; at least one silicon rod which comprises at least one filament and is arranged inside the reaction chamber; a gas supply unit which supplies input gas into the reaction chamber; an electric power supply unit connected to the vertical filament to supply electric current to the silicon rod; at least one image acquisition unit which generates an image to check the growing state of the silicon rod; and a control unit which controls at least one from the amount of current and the amount of input gas supply based on at least one among current diameter of the silicon rod determined using the image, a preset target diameter, and a preset target conversion rate. The manufacturing method of the present invention reflects growing state of a silicon rod and can effectively control the amount of electric current and the amount of input gas supply required to manufacture silicon.

Description

METHOD AND APPARATUS FOR PRODUCING SILICON [0002]

The present invention relates to a method and apparatus for manufacturing silicon.

Due to the rapid development of the solar cell industry in recent years, demand for high-purity silicon used as a raw material for solar cells is rapidly increasing. Most of the high-purity silicon currently commercialized is manufactured by a chemical vapor deposition method called Siemens method. In the Siemens method, a silicon rod composed of filaments is provided in a reaction chamber formed by a reactor, and a silicon-containing gas such as monosilane, disilane or trichlorosilane is injected into the reaction chamber through a gas inlet, Is injected. At this time, the surface of the silicon rod is heated by the applied current, and the injected introduced gas is thermally decomposed and deposited on the heated silicon rod to generate silicon.

However, in the conventional Siemens method, several manufacturing steps are repeated to reflect the characteristics of the reactor used in the production of the reactor or the internal components of the reactor, the batch characteristics in which different batch batch results are obtained even in the same reactor Perform reactor optimization. However, such a reactor optimization process consumes a lot of time, and there is a disadvantage in that it can not be confirmed whether or not the production efficiency can be improved even after the optimization.

An object of the present invention is to provide a method and an apparatus for manufacturing silicon which can reflect the growth state of the silicon rod in real time and efficiently control the amount of current and the amount of the introduced gas required for silicon production.

Another object of the present invention is to provide a method and an apparatus for producing silicon which can produce silicon under optimum conditions regardless of the characteristics of the reactor and the arrangement thereof.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention which are not mentioned can be understood by the following description and more clearly understood by the embodiments of the present invention. It will also be readily apparent that the objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

According to an aspect of the present invention, there is provided a silicon production apparatus comprising: a reactor having a reaction chamber formed therein; at least one silicon rod provided in the reaction chamber and composed of one or more filaments; An image acquiring unit connected to the vertical filament and supplying a current to the silicon rod, an image acquiring unit generating an image for confirming a growth state of the silicon rod, And a control unit for controlling at least one of a magnitude of the current and a supply amount of the supplied gas based on at least one of a current diameter of the rod, a preset target diameter, and a preset target conversion ratio.

According to another aspect of the present invention, there is provided a method of manufacturing a silicon, comprising: inputting a target diameter and a target conversion rate from a user; generating an image for confirming a growth state of a silicon rod provided in the reaction chamber; At least one of a magnitude of a current supplied to the silicon rod based on at least one of the current diameter, the target diameter and the target conversion rate, and a supply amount of an input gas supplied into the reaction chamber, And a step of controlling the control unit.

According to the present invention as described above, the growth state of the silicon rod is reflected in real time, and the amount of the current and the amount of the introduced gas required for the silicon production can be efficiently controlled.

Also, according to the present invention, there is an advantage that silicon can be manufactured under optimum conditions regardless of the characteristics of the reactor or the arrangement thereof.

1 is a configuration diagram of a silicon manufacturing apparatus according to an embodiment of the present invention;
2 is a diagram illustrating a process of determining the diameter of a silicon rod using an image obtained in an embodiment of the present invention.
3 is a flow diagram of a method of manufacturing silicon according to an embodiment of the present invention.

The above and other objects, features, and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings, which are not intended to limit the scope of the present invention. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to denote the same or similar elements.

1 is a configuration diagram of a silicon manufacturing apparatus according to an embodiment of the present invention.

1, a silicon manufacturing apparatus 10 according to an embodiment of the present invention includes a substrate 40 and a reactor 30 installed on the substrate 40. Silicon A reaction chamber 25 is formed. The reactor 30 has a bell shape in FIG. 1, but can be of any shape capable of forming the reaction chamber 25. The reactor 30 is composed of an inner wall 30a and an outer wall 30b and a coolant flows between the inner wall 30a and the outer wall 30b and inside the substrate 40 to control the temperature of the reaction chamber 25 .

In Fig. 1, a silicon rod 34 is disposed in the reaction chamber 25. The silicon rod 34 according to the present invention may be composed of one or more filaments. For example, in the embodiment shown in FIG. 1, the silicon rod 34 includes two vertical filaments 34a and 34b spaced apart from each other on a substrate 40, and a plurality of vertical filaments 34a and 34b connecting the upper ends of the vertical filaments 34a and 34b. And a filament 34c. The lower ends of the vertical filaments 34a and 34b are connected to the power supply unit 20 and the power supply unit 20 applies current to the silicon rod 34 under the control of the control unit 50. [ When current is applied by the power supply unit 20, the filaments constituting the silicon rod 34 are heated to a predetermined temperature, for example, 1000 to 1100 ° C. Alternatively, according to an embodiment, the silicon rod 34 may be composed of one or more filaments having a different structure and shape than the vertical filament and the horizontal filament.

In the embodiment of FIG. 1, only one silicon rod 34 is disposed in the reaction chamber 25, but in another embodiment of the present invention, a plurality of silicon rods may be disposed in the reaction chamber 25.

The substrate 40 is further provided with a gas inlet 42 through which the introduced gas for producing silicon is introduced and a gas outlet 44 through which the reacted gas is discharged. The inlet gas is supplied to the gas inlet 42 in accordance with the control of the control unit. The input gas contains silicon components such as monosilane, disilane, or trichlorosilane. The introduced gas introduced into the gas inlet 42 is thermally decomposed around the heated silicon rod 34 by applying an electric current, whereby a silicon component is deposited on the surface of the silicon rod 34. Silicon grows on the silicon rod 34 through this deposition process.

The silicon manufacturing apparatus 10 according to the embodiment of the present invention includes an image acquiring unit 46 for generating an image for confirming the growth state of the silicon rod 34 disposed in the reaction chamber 25 during the silicon manufacturing process, , 48). For example, the image acquiring units 46 and 48 may be formed of an optical sensor or a laser sensor or a combination thereof to capture the silicon rod 34 disposed inside the reaction chamber 25 and generate an image accordingly. The image acquisition units 46 and 48 may include separate light sources (not shown) to obtain a clearer image.

The view port 24 or 26 can be disposed on the reactor 30 to confirm the growth state of the silicon rod 34 disposed inside the reaction chamber 25 by the image acquisition units 46 and 48. The size and shape of the view ports 24 and 26 may be varied depending on the embodiment and may be made of a transparent material so that the growth status of the silicon rod 34 can be confirmed by the image acquisition units 46 and 48.

In the embodiment shown in FIG. 1, two image acquisition units 46 and 48 and corresponding two viewports 24 and 26 are shown, but in another embodiment of the present invention, Or more. 1, two image acquisition units 46 and 48 and two view ports 24 and 26 are disposed on the left side and the upper left side of the reactor 30, respectively. However, in another embodiment of the present invention, And the view port can be disposed at any position where the growth state of the silicon rod 34 in the reaction chamber 25 can be confirmed.

Meanwhile, the images of the silicon rod 34 generated through the image acquisition units 46 and 48 may be transmitted to the control unit 50 through wired or wireless communication. The control unit 50 determines the current diameter of the silicon rod 34 using the image transmitted from the image acquiring unit 46 or 48 and determines the current diameter of the silicon rod 34 based on at least one of the determined current diameter, And controls at least one of the magnitude of the current applied by the power supply unit 20 and the supply amount of the supplied gas supplied by the gas supply unit 22. [

Hereinafter, a silicon manufacturing process according to a preferred embodiment of the present invention will be described in detail with reference to FIG.

In the embodiment of the present invention, the target diameter and the target conversion ratio are set in order to efficiently control the silicon production.

Here, the target diameter means the diameter of silicon grown by the silicon deposited on the silicon rod 34 when the unit time elapses at a specific time t. As a result, the target diameter can mean the growth rate of silicon based on the unit time. Such a target diameter can be input from a user through an input unit (not shown).

Further, the introduced gas supplied into the reaction chamber 25 includes a silicon-containing gas such as monosilane, disilane, or trichlorosilane, that is, a silane gas. The rate at which silicon contained in the silane gas is converted into actual silicon through the manufacturing apparatus shown in FIG. 1 is referred to as a conversion rate. The user can input a desired conversion rate through a input unit (not shown) as a constant or a time-dependent value (for example, a value of 0 to 100%). Also, the user can input the ratio of the remaining gas included in the input gas together with silane gas as a constant or time-dependent value through an input unit (not shown).

Thereafter, the control unit 50 applies a current to the silicon rod 34 through the power supply unit 20 at a predetermined initial current value. Further, the control unit 50 supplies the introduced gas into the reaction chamber 25 through the gas supply unit 22 at a predetermined initial supply amount. Accordingly, the silicon rod 34 is heated to a predetermined temperature (for example, 1000 to 1100 ° C), and the silicon contained in the introduced gas is deposited on the heated silicon rod 34 to grow silicon.

At this time, the image acquisition units 46 and 48 take an image of the silicon rod 34 through the view ports 24 and 26 to generate an image for confirming the growth state of the silicon rod 34. The thus generated image is transmitted to the control unit 50.

The control unit 50 analyzes the image transferred from the image acquisition units 46 and 48 to determine the current diameter of the photographed silicon rod 34. One of various image analysis methods that exist conventionally can be used for the control section 50 to determine the current diameter of the actual silicon rod 34 through the image of the silicon rod 34. [

FIG. 2 is a view for explaining a process of determining the diameter of a silicon rod using an image obtained in an embodiment of the present invention. 2 (a) shows the original image transferred from the image acquisition units 46 and 48. In FIG. If the number of captured image model channels is m (for example, m = 3 for an RGB model and m = 4 for a CMYK model), the original image has (the number of horizontal pixels x the number of vertical pixels x m). Assuming that the number of color depths of the original image is n, all the components of the matrix have a value of 0 to (2 ⁿ -1).

2 (b), the controller 50 compares the pixel value of the specific pixel in the original image with the pixel value of the surrounding pixel, and emphasizes the portion in which the value changes abruptly, (For example, a silicon rod) in the substrate.

Next, the control unit 50 converts the image into a gray scale as shown in FIG. 2 (c). (The number of horizontal pixels × the number of vertical pixels × m) are assumed to be the coordinates of the original image, one pixel coordinate has m values, and the m values of m (Number of horizontal pixels × number of vertical pixels × m) is converted into a matrix of (number of horizontal pixels × number of vertical pixels × 1). Thus, the grayscaled image has a value between 0 and (2 ⁿ -1) per pixel.

Next, the control unit 50 binarizes the gray-scale image as shown in (d) of FIG. That is, the controller 50 converts a pixel having a larger value based on a specific pixel value into a pixel having a smaller value of 0 by converting the pixel to 0, thereby converting the gray-scaled image into a binary image having black and white (binary) image. Here, a specific pixel value is called a boundary value. In general, the user observes the image and uses the designated value or the designated value in the same manner as the Otsu's method.

Next, the control unit 50 corrects the previously generated binary image by various methods. Since the temperature inside the reaction chamber 25 is very high, the image captured by the image acquisition units 46 and 48 may be distorted due to heat and light. Therefore, if an object that should exist in the image does not appear due to the distortion of light, if there exists an area in which there is no object between the areas where the object exists, the process of filling the object in the area can be repeatedly performed. Also, in order to compensate for the distortion due to the high temperature, the edges of the objects in the image are distorted. To correct this, the outermost line of each object is extracted and the outermost line is transformed as narrow as possible, The inside can be replenished again. Figure 2 (e) shows the final image thus corrected.

The controller 50 analyzes the degree of inclination of the object in the corrected final image, that is, the silicon rod, calculates the number of pixels in the horizontal direction of each vertical axis when the object is upright, and then selects the representative object length. The representative object length can be an average value or a mode value or a median value of the calculated pixel numbers. The length of the representative object determined by the number of pixels is converted into the actual length through a scale that is known in advance, so that the diameter of the silicon column at the time of image shooting can be calculated.

A series of processes from image generation by the image acquisition units 46 and 48 to calculation of the diameter by the control unit 50 can be repeatedly performed at predetermined time intervals. In this case, the time interval can be set to a time desired by the user from 1 second to 10 hours, and in particular, to a time between 1 minute and 1 hour.

The control unit 50 can determine the current diameter of the silicon rod 34 during the silicon manufacturing process using the image generated by the image acquisition units 46 and 48 through the above process. In one embodiment of the present invention, the control unit 50 determines the magnitude of the current supplied by the power supply unit 20 based on the diameter of the silicon rod 34 and at least one of the set target diameter and the target conversion ratio, And the amount of the supplied gas supplied by the gas supply unit 22 are controlled as follows.

A. Current control

A current diameter of the silicon rod 34 in the diameter of a unit of time the silicon rod 34 since at a particular time t, that is as a target diameter D _{t + 1,} and determined by the controller 50 a particular time t D _t , The amount of heat required by the silicon rod 34 is expressed by Equation (1).

In Equation (1),? Q represents the heat amount, c represents the specific heat of the silicon rod 34,? M represents the mass change amount of the silicon rod 34, and T represents the temperature of the silicon rod 34.

At this time, the mass change amount? M of the silicon rod 34 can be expressed by the following equation (2).

L is the total length of the silicon rod 34 (the length of the vertical filaments 34a and 34b), and L is the total length of the silicon rod 34. In the formula (2), d _si is the density of the silicon rod 34, And the length of the horizontal filament 34c).

Substituting? M in the equation (2) into the equation (1), the following is obtained.

Where V represents the voltage magnitude currently applied to the silicon rod 34 and R represents the resistance value of the silicon rod 34.

(3), the change amount? I of the current magnitude to be applied to the silicon rod 34 for a unit time at a specific time t can be determined as follows in order to achieve the previously set target diameter.

Here, R _t represents the resistance value of the silicon rod 34, and I _t represents the current value supplied to the silicon rod 34, respectively.

In one embodiment of the present invention, the control unit 50 calculates the unit time D _t at a specific time t using the target diameter D _{t + 1} and the current diameter D _t of the silicon rod 34 as shown in Equation (4) And then controls the power supply unit 20 to apply the current according to the determined amount of change. The power supply unit 20 can change the magnitude of the current supplied linearly or nonlinearly for a unit time.

On the other hand, the controller 50 changes the magnitude of the current applied to the silicon rod 34 using the change amount? I determined by Equation (4) You can further compensate for this.

In Equation (5), CC _t represents a correction coefficient at a specific time t. Also, the expected value t represents an expected value expected to appear in the silicon rod 34 when the variation amount? I of the current magnitude determined by Equation 4 is applied, Measured value of the silicon rod 34 actually measured when the change amount? I of the current magnitude determined by [4] is applied. The values used for expected values and actual values at this time mean all values measurable from the silicon rod, such as the diameter or cross-sectional area of the silicon rod, and all values that can be generated by converting all of these measurable values. Also, two or more correction coefficients may be used according to the embodiment. At this time, the correction coefficient at the start time, that is, the specific time t = 0, is defined as 1.

B. Inlet gas control

As described above, the input gas supplied into the reaction chamber 25 includes a silicon-containing gas such as monosilane, disilane, or trichlorosilane, that is, a silane gas. The silane gas contains a certain amount of silicon, and some of these silicones are deposited on the silicon rod 34 to form silicon. The rate at which the silicon contained in the silane gas is actually converted to silicon is referred to as a conversion rate

When the conversion rate at a specific time t is CR _t , the amount (? S) of silicon contained in at least one silane gas contained in the input gas is defined as follows.

The ratio of the volume of each silane gas to the volume of the entire silane gas is defined as r _SGi and the ratio of the volume of the entire silane gas to the volume of the introduced gas is defined as r _silane , the volume (FG _{t + 1} ) of the input gas after a unit time at a specific time t with silicon of? s is defined as follows.

MW _Si represents the molecular weight of the silicon contained in the introduced gas, and MW _SGi represents the molecular weight of the silane gas i.

For example, it is assumed that the amount of silicon (? S) contained in the input gas is 100 g, the monosilane occupies 40% and the trichlorosilane occupies 60% of the silane gas contained in the input gas. If the ratio of the silane gas in the input gas is 80%, 40 g of 100 g of silicon (Δs) will be contained in the monosilane and 60 g in the trichlorosilane, respectively. Since the total amount of silicon contained in the monosilane or the trichlorosilane is calculated, the total volume of the silane gas is calculated. The silane gas having such a volume is calculated as 80 %, So that the volume of the input gas after the unit time can be finally calculated at a specific time t.

The control unit 50 controls the gas supply unit 22 to control the amount of the introduced gas after the unit time at a specific time t by using the volume of the introduced gas after the unit time at the specific time t thus calculated.

The silicon manufacturing apparatus 10 according to the present invention can more efficiently achieve the preset target diameter and target conversion ratio in the production of silicon through the control of the magnitude of the current and the amount of the introduced gas.

3 is a flow chart of a method of manufacturing silicon according to an embodiment of the present invention.

The silicon manufacturing apparatus 10 according to the present invention can more efficiently achieve the preset target diameter and target conversion ratio in the production of silicon through the control of the magnitude of the current and the amount of the introduced gas.

3 is a flow chart of a method of manufacturing silicon according to an embodiment of the present invention.

Referring to FIG. 3, a target diameter and a target conversion rate are input from a user (S302). Thereafter, a current is applied to the silicon rod for silicon production, and an input gas can be supplied into the reaction chamber.

Next, the silicon rod provided in the reaction chamber is photographed to generate an image of the silicon rod (S304), and the current diameter of the silicon rod is determined using the generated image (S306).

Then, at least one of the magnitude of the current supplied to the silicon rod and the supply amount of the supplied gas supplied into the reaction chamber based on at least one of the current diameter, the target diameter and the target conversion rate of the silicon rod is controlled (S308).

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, But the present invention is not limited thereto.

Claims (11)

A reactor in which a reaction chamber is formed;
At least one silicon rod disposed within the reaction chamber and comprising at least one filament;
A gas supply unit for supplying an input gas into the reaction chamber;
A power supply connected to the filament to supply current to the silicon rod;
An image obtaining unit for generating an image for confirming a growth state of the silicon rod; And
A control unit for controlling at least one of a magnitude of the current and a supply amount of the introduced gas based on at least one of a current diameter of the silicon rod determined using the image, a preset target diameter, and a predetermined target conversion rate
≪ / RTI >
The method according to claim 1,
At least one view port for confirming the growth state of the silicon rod is formed on the reactor by the image acquiring unit
Silicon manufacturing device.
The method according to claim 1,
The control unit
An image processor for calculating the current diameter of the silicon rod using the image
≪ / RTI >
The method according to claim 1,
The control unit
An input unit for receiving the target diameter and the target conversion rate from a user
≪ / RTI >
The method according to claim 1,
The control unit
The magnitude of the current is controlled using the current change amount? I determined by the following equation (1)
Silicon manufacturing device.

[Equation 1]

(Here, c is the specific heat of the silicon rod, T is the temperature of the silicon rod, L is the total length, d _si is the density of the silicon load of the silicon rod, t is a particular time, D _t is the current diameter, D _{t +1} is a target diameter after a unit time at a specific time t, R _t is a resistance value of the silicon rod, and I _t is a current current value supplied to the silicon rod)
6. The method of claim 5,
The control unit
Comparing an expected value when the current change amount is applied and an actual value of the silicon rod measured after the current change amount is applied, and controlling the magnitude of the current according to the comparison result
Silicon manufacturing device.
The method according to claim 1,
The control unit
The supply amount of the input gas is determined using the following equation (2)
Silicon manufacturing device.

&Quot; (2) "

(Where, FG _{t + 1} is volume, L is the total length, d _si is the density of the silicon rod, D _t is the current diameter, D _{t + 1} of the silicon rod in the input gas after the unit time in a certain time t is a particular _M r _Si is the molecular weight of silicon contained in the input gas, r _silane is the ratio of the volume of the entire silane gas to the volume of the input gas, CR _{t + 1} is the target conversion rate, MW _SGi is the molecular weight of the silane gas i, r _SGi is the ratio of the volume of the silane gas i to the volume of the total silane gas, and d _SGi is the density of the silane gas i)
Receiving a target diameter and a target conversion rate from a user;
Generating an image for confirming a growth state of the silicon rod provided in the reaction chamber;
Determining the current diameter of the silicon rod using the image; And
Controlling at least one of a magnitude of a current supplied to the silicon rod based on at least one of the current diameter, the target diameter, and the target conversion rate and a supply amount of an input gas supplied into the reaction chamber,
≪ / RTI >
9. The method of claim 8,
The magnitude of the current
Is controlled using the current change amount? I determined by the following equation (1)
≪ / RTI >

[Equation 1]

(Here, c is the specific heat of the silicon rod, T is the temperature of the silicon rod, L is the total length, d _si is the density of the silicon load of the silicon rod, t is a particular time, D _t is the current diameter, D _{t +1} is a target diameter after a unit time at a specific time t, R _t is a resistance value of the silicon rod, and I _t is a current current value supplied to the silicon rod)
10. The method of claim 9,
Comparing an expected value when the current change amount is applied and an actual value of the silicon rod measured after the current change amount is applied and controlling a magnitude of the current according to a comparison result,
≪ / RTI >
9. The method of claim 8,
The supply amount of the input gas is
Is determined using the following equation (2)
≪ / RTI >

&Quot; (2) "

(Where, FG _{t + 1} is volume, L is the total length, d _si is the density of the silicon rod, D _t is the current diameter, D _{t + 1} of the silicon rod in the input gas after the unit time in a certain time t is a particular _M r _Si is the molecular weight of silicon contained in the input gas, r _silane is the volume ratio of the silane gas to the volume of the input gas, CR _{t + 1} is the target conversion rate, MW _SGi is the silane R _SGi is the volume ratio of the silane gas i to the total volume of the silane gas, and d _SGi is the density of the silane gas i)

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