KR200396732Y1 - Silicon crystal growth controllar using image binarization - Google Patents

Abstract

The present invention relates to a silicon crystal growth control device.

More specifically, the present invention binarizes the acquired image and coagulates using the binarized image so as to prevent the error of judging multiple targets by tracking the brightness of the reflected light disappearing from the camera momentarily. The present invention relates to a silicon crystal growth control apparatus for measuring the diameter of an interface to perform ingot pulling rate control and temperature control of a polycrystalline silicon solution according to the measured diameter.

Description

Silicon crystal growth controllar using image binarization

The present invention relates to a silicon crystal growth control device.

More specifically, the present invention binarizes the acquired image and coagulates using the binarized image so as to prevent the error of judging multiple targets by tracking the brightness of the reflected light disappearing from the camera momentarily. The present invention relates to a silicon crystal growth control apparatus for measuring the diameter of an interface to perform ingot pulling rate control and temperature control of a polycrystalline silicon solution according to the measured diameter.

Single crystal, or monocrystalline silicon, is a starting materiel in most processes for manufacturing semiconductor electronic components. Crystal pulling machines using the Czochralski process produce most of the single crystal silicon.

Briefly stated, the Czochralski process involves melting high purity polycrystalline silicon introduced into a quartz crucible installed in a specially designed furnace.

After the silicon is melted in the crucible, the seed crystals are brought down into contact with the molten silicon by a crystal lifting mechanism. The mechanism then pulls out the seeds and raises the crystal growing from the silicone melt.

In general, the process for growing a single crystal ingot is classified into high purity polycrystalline silicon, which is a raw material and an auxiliary material capable of growing a single crystal ingot in a quartz crucible placed inside a chamber of the single crystal ingot growth apparatus. Preparation of charge for stacking poly silicon and dopant and high temperature polycrystalline silicon to be melted by high temperature heating with electric heater while rotating quartz crucible Melting, dipping contacting seeds for growing single crystal ingots with polycrystalline silicon melt, and initial loss due to heat while minimizing the diameter of single crystal ingots growing along the seeds Necking process to raise and grow single crystal ingot by pull up driving part to reduce The shoulder driving process of pulling and growing the ingot at a relatively slow speed compared to the pulling speed of the necking process to expand the single crystal ingot to the desired crystal diameter by the pulling driver, and the diameter of the ingot is determined Body growing process that grows to the desired ingot length when it grows to the diameter, and tailing process that separates the ingot from the polycrystalline silicon melt by growing it by decreasing the diameter of the ingot when the length of the ingot grows to the desired length. tailing, cool-down to cool the separated ingot and quartz crucible, ingot removal to remove the cooled ingot from the chamber, oxygen, resistivity, carbon concentration of the removed ingot, etc. It is subdivided into evaluation process by measuring and evaluating.

Among these monocrystalline silicon ingot growth processes, necking, shouldering, body drawing, and tailing processes grow to the diameter and length of the desired single crystal ingot while the seeds are in contact with the polycrystalline silicon melt. Process variables should be considered.

Representative process variables include the rotation of the ingot to improve the temperature field and uniform concentration of impurities in the polycrystalline silicon melt around the solidification interface (meniscus) where the seeds or ingots in solid contact with the liquid polycrystalline silicon melt are in contact. Ingot diameter affecting the rotation of the quartz crucible to maintain a uniform temperature field of the entire polycrystalline silicon melt, the ingot pulling speed of the ingot pulling drive associated with precipitation bonding, and the probability of occurrence of micro precipitation defects and dislocations Change, the temperature of the polycrystalline silicon melt due to the reduction of heat transferred from the electric heater, and the like.

In particular, the process variables related to the ingot diameter change among the process variables are the ingot pulling speed and the temperature of the polycrystalline silicon melt, and the diameter of the single crystal ingot is directly affected by this process variable. Therefore, the ingot diameter is continuously measured during the process. Other process parameters, such as the pulling rate and the temperature of the polycrystalline silicon melt, should be adjusted.

Therefore, a single crystal silicon ingot growth apparatus is usually equipped with various process parameter adjusting means for growing the desired single crystal silicon ingot by satisfying each process variable to a desired condition.

The currently available Czochralski growth method has been satisfactory for growing single crystal silicon useful in a wide range of fields, but further improvements are still needed. For example, it is desirable to minimize the variation in diameter throughout the growth process to improve the shape and quality of the grown crystals.

The problem of minimizing the deviation of the ingot diameter is related to the reliable measurement of the ingot diameter.

For reference, US Pat. Nos. 5,665,159 and 5,653,799 describe systems and methods for accurately and reliably measuring crystal diameters for use in controlling the growth process of single crystal silicon, respectively. Advantageously, the systems and methods of these patents accurately determine the diameter of growth crystals by processing images of the crystal-melt interface produced by the camera.

In addition, Korean Patent Application No. 2001-7004324 discloses "silicon crystal growth control method and system", the disclosed "silicon crystal growth control method and system" shows the position of the melt level and the reflector in the Czochralski single crystal growth apparatus. Determination methods and systems are described.

The specification of the disclosed "silicon crystal growth control method and system" discloses a heated crucible crystal growth apparatus comprising a silicon melt for pulling crystals, and the crystal growth apparatus also has a central hole for pulling through the crystals. It has a reflector located inside the crucible.

In the disclosed " silicon crystal growth control method and system ", the camera produces an image of the reflector portion and the reflector portion of the reflector visible on the upper surface of the melt, and the image processor processes the image as a function of the pixel value of the image to reflect the edges of the reflector. Detect the reflector edge at and In the disclosed " silicon crystal growth control method and system ", the control circuit determines the distance from the camera to the reflector and the distance from the camera to the reflector based on the relative position of the detected edges in the image, the control circuit based on the determined distance. One or more parameters indicative of the conditions of the crystal growth mechanism are determined and the device is controlled in accordance with the determined parameters.

At this time, in the disclosed " silicon crystal growth control method and system ", the image processor performs some tasks to analyze the image, including edge detection to analyze gray level transformations (as a function of image intensity) in defined regions of the image. . In order to find and calculate the edges of an image, various edge search operators, or algorithms, are known to those skilled in the art. For example, suitable edge detection tasks include the Canny or Hough algorithm. In addition to intensity, other features of the image, such as intensity gradient, color or contrast, are used to optically distinguish other objects on the surface of the melt at the solidification interface or the melt itself.

On the other hand, according to the prior art, when measuring the diameter of the ingot, the internal environment of the chamber is changed to a liquid solution by heating the heater (Heater) in the state of loading the granular raw material.

This is a crucible containing a substance that is actually dissolved in a state in which water is contained in the container and the surface is formed in a gentle wave when a physical force is applied to rotate the container or inject air from above. Argon gas (Ar Gas) is a state that is injected to maintain the degree of vacuum in the chamber (Chamber).

As shown in FIG. 1, when the external physical force is applied, the reflected light generated by the gentle shaking causes a lot of confusion to the camera looking through the chamber's view port. Can give

The camera, which measures the diameter of the coagulation interface (Meniscus), the brightest spot, tracks the brightness of the reflected light that protrudes and disappears momentarily, which is caused by an error of judging several targets. That is, as can be seen in Figure 1, the detection of the normal coagulation interface is 2 to 4 times, but due to the influence of the instantaneous reflected light of the squirting solution, the camera cannot find the coagulation interface of the diameter to be measured once. To 4 or 3 to 4 is determined as the coagulation interface.

The above problem is the biggest error factor for the purpose of interfacing the analog signal with the programmable logic controller through the analog output card through the analysis of the program by measuring the diameter of the ingot which is grown as the biggest obstacle of the diameter measurement.

Therefore, the present invention was devised to solve the above problems, and the camera is initially distracted by limiting the range that the camera can recognize while clearly distinguishing the brightest part from the other part by binarizing the composition of the image. Image binarization that prevents errors that were tracked by misrecognizing the fluctuating reflection light as a focal point, stably combines the diameter image into a binarized image, calculates it, and provides the output value as a default for controlling the tensile speed and temperature. An object of the present invention is to provide a silicon crystal growth control apparatus using the same.

The apparatus of the present invention for achieving the above object is a video image frame buffer which is installed in the chamber of the crystal growth system and receives and stores the image from the camera to generate an image of the contact surface between the melt and the crystal including the solidification interface ; An analog / digital converter for receiving and digitizing image data from the video image frame buffer; Receives and displays an image stored in the video image frame buffer, binarizes the received image using the stored threshold value, detects an edge, calculates the outermost edge, and calculates the diameter of the solidification interface using the converted value. Diameter measuring means for outputting; And an analog output card which receives the diameter value calculated from the diameter measuring means, converts the analog value into a corresponding analog value, and outputs the analog value to a programmable logic controller of the crystal growth system.

2, a silicon crystal growth control apparatus using image binarization according to a preferred embodiment of the present invention will be described in detail with reference to FIG. 2.

2 is a block diagram of a crystal growth system using a silicon crystal growth control apparatus using binarization according to an embodiment of the present invention.

Referring to the drawings, the crystal growth system using the silicon crystal growth control apparatus using binarization according to an embodiment of the present invention is shown to use the Czochralski crystal growth apparatus 13. The crystal growth system measures a plurality of parameters that control the crystal growth process. The Czochralski crystal growth apparatus 13 includes a vacuum chamber 15 surrounding the crucible 19. Heating means such as a resistance heater 21 surrounds the crucible 19, and the insulator 23 is arranged on the inner wall of the vacuum chamber 15 and surrounded by a chamber cooling jacket (not shown) supplied with water. A representative (not shown) vacuum pump supplies an inert gas such as helium or argon gas while removing gas in the vacuum chamber 15.

According to the Czochralski single crystal growth process, polycrystalline silicon, that is, a certain amount of polysilicon, is loaded into the crucible 19. The heater power source 27 flows a current through the resistance heater 21 to melt the input, thereby forming a silicon melt 29 which pulls up the single crystal 31.

As is known in the art, the single crystal 31 begins to grow on the pull shaft 37, ie, the seed crystal 35 attached to the cable. As shown in FIG. 2, the single crystal 31 and the crucible 19 generally have a common axis of symmetry 39.

During heating and crystal pulling, the crucible drive unit 43 rotates the crucible 19 (ie clockwise). In addition, the crucible drive unit 43 raises and lowers the crucible 19 as desired during the growth process. For example, in order to maintain the desired height reference 45, when the melt 29 is depleted, the crucible drive unit 43 raises the crucible 19.

The crystal drive unit 47 rotates the cable 37 in a direction opposite to the direction in which the crucible drive unit 43 rotates the crucible 19. In addition, the crystal drive unit 47 raises and lowers the crystal 31 in relation to the desired melt level 45 during crystal growth.

In one embodiment, the crystal growth apparatus 13 preheats the seed crystals 35 by lowering them into near contact with the molten silicon melt 29 contained in the crucible 19. After preheating, the crystal drive unit 47 continues to lower the seed crystal 35 through the cable 37 to contact the melt 29 of the melt level 45. As the seed crystals 35 are melted, the crystal drive unit 47 slowly retracts, i.e., raises, the seed crystals in the melt 29. The seed crystal 35 draws silicon from the melt 29 and grows with the silicon single crystal 31 retracted.

The crystal drive unit 47 rotates the crystal 31 at a reference speed while raising the crystal 31 from the melt 29. The crucible drive unit 43 similarly rotates the crucible 19 at a different reference speed, but usually rotates in a direction opposite to the direction of rotation of the crystal 31.

The silicon crystal growth control device 51 initially controls the retreat speed and causes neck down of the crystal 31 with the power supplied by the heater power supply 27 to the heater 21.

Preferably, the crystal growth apparatus while drawing the seed crystals 35 from the melt 29

(13) grows the crystal neck to a substantially constant diameter. After the neck reaches the desired length, the silicon crystal growth control device 51 controls the rotation, pulling and / or heating parameters that increase the diameter of the crystal 31 in a cone-shaped manner to reach the desired crystal diameter. do.

Once the desired crystal diameter is reached, the silicon crystal growth control device 51 controls the growth parameters to maintain a relatively constant diameter measured until the end of the process. In this regard, the pulling speed and the heating are increased to allow the end of the single crystal 31 to form a tapered portion, usually decreasing in diameter.

Preferably, the silicon crystal growth control device 51 obtains an image centering on the solidification interface of the crystal 31 using the camera 53. In this case, the camera 53 is a charge coupled device (CCD) camera. If the body diameter is 6 inches or 8 inches, the head detachable type is unnecessary.

Because when the body diameter is 6 inches or 8 inches, it is not necessary to apply a separate magnetic field to stabilize the inside of the vacuum chamber 15, but when 12 inches or more, the magnetic field is applied to the vacuum chamber 15 so that the head is not separated. This is because the use of the magnetic field affects the signal processing part and the signal may be distorted accordingly.

The camera 53 is mounted on a view port (not shown) of the chamber 15 and generally aims at the intersection of the longitudinal axis 39 and the melt level 45 (see FIG. 4).

For example, the operator of the Czochralski crystal growth apparatus 13 generally positions the camera 53 at an angle of about 45 ° to 60 ° in terms of the longitudinal axis 39. The image produced by the camera 53 preferably includes a portion of the meniscus 101 at the contact surface between the melt 29 and the crystal 31 (see FIG. 4).

The melt 29 and the crystal 31 are inherently self-luminous to supply light to the camera 53 without using an external light source. Additional cameras may also be used to provide other fields of view. In addition to the signal processing of the camera 53, the silicon crystal growth control device 51 also processes signals from other sensors. For example, a temperature sensor 59, such as a photo cell, may be used to measure the surface temperature of the melt.

3 is a block diagram of a silicon crystal growth control apparatus according to an embodiment of the present invention, Figure 8 is a flow chart of a silicon crystal growth control method according to an embodiment of the present invention, with reference to Figures 3 and 8 Referring to a preferred embodiment of the invention as follows.

Referring to FIG. 3, the silicon crystal growth control apparatus according to an embodiment of the present invention includes a video image frame buffer 63, an analog / digital converter 65, a controller 67, a display unit 69, and an input unit 71. And an analog output card 73 and a memory 75.

First, in step S110 of FIG. 8, the camera 53 controls the silicon crystal growth control of the image inside the crucible 19 through a line 61 (that is, an RS-170 video cable) so that the controller 67 may acquire an image. To the device 51.

In more detail, the camera 53 captures an image inside the crucible 19 and converts it into an analog signal, and then converts the image as shown in FIG. 5 through a line 61 (ie, an RS-170 video cable) to a video image frame buffer. (63; video image frame buffer).

At this time, the video image frame buffer 63 of the silicon crystal growth control device 51 is internal as shown in FIG. 5 of the crucible 19 generated by the camera 53 at regular intervals (for example, every 1 second). Get the image. That is, at predetermined time intervals, the video image frame buffer 63 scans the interior of the crucible 19. The internal image of the crucible 19 captured by the video image frame buffer 63 is composed of a plurality of pixels. As is known in the art, each pixel has a representative value of the image optical characteristic. For example, the pixel value, ie the gray layer, corresponds to the intensity of the pixel. In this case, as shown in FIG. 5, the image forms a crescent-shaped ring with a bright coagulation interface, and the remaining portion is pale gray.

Next, the video image frame buffer 63 converts the image received from the camera 53 into a digital signal through the analog / digital converter 65 and then transmits the buffered image to the controller 67.

The controller 67 receives the image from the camera 53 through the video image frame buffer 63 and the analog / digital converter 65, and stores the received image in the memory 75. The display unit 69 according to a user's request. ).

The controller 67 first performs image binarization of the step S120 of FIG. 8 with respect to the image transmitted from the camera 53 to obtain the diameter of the ingot, and stores the binarized image in the memory 75. It displays on the display part 69 as needed.

Here, image binarization refers to converting an image to black / white based on a threshold.

In general, image binarization is an important process in many vision systems. And the accuracy of binarization thresholds directly affects the binary image resulting from the processing. Therefore, in order to detect the solidification interface, it is necessary to find the 'Threshold Point' that accurately separates the gray scale values of the solidification interface from the background.

In the simplest implementation of this image binarization, the output is a binary image representing the segmentation. For example, black pixels correspond to the background and white pixels correspond to the solidification interface (or vice versa). Therefore, in a simple implementation, partitioning is determined by a single parameter known as the intensity threshold. Once passed, each pixel in the image is compared to this threshold. If the intensity of the pixel is greater than the threshold, the pixel is designated white at the output. If it is smaller than the threshold, it is set to black.

In this case, the binarized image obtained from the image of FIG. 5 is illustrated in FIG. 6, where the background portion is treated with black pixels, and the portion representing the solidification interface is treated with white pixels.

The controller 67 detects the edge of step S130 of FIG. 8 using the binarized image, selects the outermost edge of step S140, and finds the diameter of the coagulation interface by analyzing the selected edge of step S150. The diameter calculated according to step S160 is stored.

Then, the scanning is performed several times according to the step S170, and the average value of the calculated diameter is obtained according to the step S180. A control signal is generated based on the diameter according to the average value according to the step S190, and output to the analog output card 73.

At this time, the control unit 67 performs some operations for analyzing the image, including an edge detection operation for analyzing gray level changes (as a function of image intensity) in a predetermined region of the image. Various edge search operators, or algorithms, for finding and calculating the edges of an image are known to those skilled in the art. For example, suitable edge detection tasks include the Canny or Hough algorithm. In addition to intensity, other properties of the image, such as intensity gradient, color, or contrast, may be used to optically distinguish other objects on the surface 99 of the melt 29 at the solidification interface 101 or the melt 29 itself.

In the present invention, as shown in FIG. 7, the controller 67 performs edge detection. An edge is defined as a region within an image that has a relatively large change in the gray level of a relatively small spatial region. Other image optical properties, such as color or contrast, in addition to or instead of intensity and intensity gradient, may also be searched to find edge coordinates.

As shown in FIG. 7, the controller 67 inspects the pixel to detect the left outermost edge 113 of the solidification interface 101, and detects the right outermost edge 115, wherein the left outermost edge ( The distance across the image between 113 and the right outermost edge 115 provides a diameter. As an embodiment of the present invention, the edge of the image is determined in relation to the (X, Y) coordinate system having an origin in the lower left corner of the image. The controller 67 detects the minimum X-position value of the left edge and the maximum x-position of the right edge.

The control unit 67 is obtained by subtracting the minimum x-position value from the maximum x-position value in order to calculate the diameter. Then, the control unit 67 converts the difference between the obtained coordinate values into a substantial distance value to determine the diameter.

Thereafter, the control unit 67 repeats a predetermined number of scanning steps, repeats step S110 to step S160 of FIG. 8 to determine the diameter according to the number of scanning times, and adds the determined diameters to calculate an average value.

The controller 67 generates a control signal corresponding to the measured diameter value and outputs the control signal to the analog output card 73.

Then, according to step S190 of FIG. 8, the analog output card 73 generates a voltage value of 0 to 10 V according to the input control signal, for example, and generates the generated voltage value as a programmable logic controller 79. To send).

The programmable logic controller 79 transmits a control signal to the crystal growth apparatus 13 based on the voltage value input from the analog output card 73, receives information about the melt temperature from the temperature sensor 59, and receives the information. The control signal is transmitted to the heater power source 27 to control the melt temperature controlling the growth process.

4 is a view for explaining a camera installation position of FIG.

As shown, crystal 31 generally consists of a crystalline silicon (ie ingot) cylinder body.

Crystals that grow like crystal 31, although generally cylindrical, do not have a generally even diameter. For this reason, the diameter may vary slightly along different axis positions along the axis 39.

Moreover, the diameter of the crystal 31 is different at different stages of crystal growth (ie, seed, neck, crown, shoulder, body and end cone). The surface 99 of the melt 29 has a liquid coagulation interface 101 formed at the interface between the crystal 31 and the melt 29.

As is known in the art, in the image obtained with the camera 53, the solidification interface 101 appears as a bright ring near the crystal 31. The camera 53 is mounted to the viewing window of the chamber 15 and is generally aiming at the intersection between the axis 39 and the surface 99 of the melt 29. Camera 53 is preferably calibrated to know the focal length and image size accurately. As shown in FIG. 4, the height H and the radius R indicate the position of the camera 53. In the illustrated embodiment, the height H is measured relative to the melt height 45.

9 shows an initialization operation of the silicon crystal growth control apparatus according to an embodiment of the present invention. Beginning at step S210, the initialization task requires input of the known data to the controller 67. In this case, the user interface screen used is shown in FIGS. 10A to 10G.

Referring to FIG. 10A, the user interface screen includes an image window for displaying an image acquired from a camera, a setting button for inputting an initial value, an inspection start button for instructing a diameter measurement start, and an end for diameter measurement. End button, current inspection site display to display current inspection site, binarization conversion button to convert gray scale screen to binarization screen, diameter measurement result display to show diameter measurement results, output voltage value showing output voltage value A display unit and a threshold value input unit for inputting a threshold value for image binarization are provided.

When the inspection start button is pressed on the screen, the controller performs a diameter measurement operation, and when the end button is pressed, the diameter measurement operation is terminated. At this time, whether the current inspection site is a neck or a body is displayed on the current inspection site display unit.

In addition, when the binarization conversion button is pressed on the screen, the controller performs binarization on the image acquired from the camera to display the binarized image on the image window.

When the threshold value conversion button is pressed, a threshold value input window is activated to allow a user to input a threshold value, and perform image binarization according to the input threshold value.

On the screen, the diameter measurement result display section is provided with a diameter measurement value display section (for example, 6.88 mm on the screen) for displaying the measurement diameter and a pixel number display section (for example, 44.3 pixels on the screen) for displaying the number of pixels.

Here, the output voltage display unit displays the output voltage according to the measured diameter. For example, when the measured diameter is 6.88 mm, 0.69 V is output.

On the other hand, when the user presses the setting button (step S210), and proceeds to the initialization mode, at this time, the screen provided is Figure 10b.

Referring to FIG. 10B, a scanning frequency adjustment button, a diameter limit setting button for each process, a length adjustment button, an area adjustment button, an edge adjustment button, and the like are provided for initialization.

At this time, when the user presses the scanning count adjustment button (step S220), the scanning count adjustment screen of FIG. 10C is provided, and the provided screen shows the currently set scanning count setting value and a scanning number for inputting the desired scanning count Shows the frequency setting window. When the user inputs the desired number of scanning times in the scanning count setting value input window and presses the setting completion, the scanning count adjustment initialization operation is completed (step S225).

Meanwhile, when the user presses the diameter limit setting button for each process (FIG. S230), the diameter limit setting screen for each process of FIG. 10D is provided, and the provided screen shows the neck upper limit value, the shoulder upper limit value, and the body upper limit value as the current value. An input window is provided so that each upper limit value can be changed (step S235). The diameter limit of each process is to be able to move on to the next process when the value exceeds the set value.

Next, when the user presses the length adjustment button (step S240), a window (not shown) for inputting a conversion value that can be converted into an actual diameter value from the number of pixels obtained from the outermost edge is provided and converted into the provided window. By inputting a value, it can be converted into the actual diameter value from the number of pixels (step S245).

In addition, when the user presses an area adjustment button (step S260), the area adjustment screen of FIG. 10E is provided, and the area adjustment screen is provided with windows 1, 2, and 3.

Window 1 is the area where the whole image is viewed. It means the area to find the first inspection area. When the edge is found, the window 2 is the area that catches the neck according to the distance of the edge. According to the shoulder and the body holding area.

For this purpose, an area to be adjusted is first selected (step S255). In other words, when the window 1, window 2, window 3 is selected, the area adjustment screen of FIG. 10F is provided, and the area bar is pressed to adjust the slide bar to make a desired size. That is, in the area adjustment screen of FIG. 10F, since the area is a rectangle, the designation is completed by specifying the height of the upper line, the left end of the upper line, the depth of the lower line, and the right end point of the lower line based on the center. Therefore, adjust the area by moving the slide bars pointing left, top, bottom and right.

Then, press the setting button to save the set area. Pressing the set button at this time closes the area adjustment window (step S257).

Next, when the user presses the edge adjustment button (step S260), the screen of FIG. 10G is provided, and the provided screen includes a threshold value input window, a width input window, a gradient input window, a ratio input window, an area input window, and a pound input. A window and a result input window are provided.

In this case, the threshold value refers to an edge value for determining whether a solidification interface is used to detect an edge. Since the binarization of an image has already been performed, a value of 1 may be input.

Next, the width refers to the number of pixels used to obtain the scale value of the image. Since the width of the image is already performed, the width may be represented as 1. Of course, when image binarization is not performed, the edge is detected by comparing the average of the sum of the respective image scale values of the corresponding number of pixels with the average value of the neighboring image scale values.

Incidentally, the inclination is the inclination of the intensity, and since the image binarization has already been performed, it may be represented as 1. The ratio refers to the interval of the line to be actually inspected, and the line represents the line to be actually inspected in the inspection area.

The pounds let you mark the edge you are looking for, and the result is the mark that shows the outermost edge.

Since the binarization of the image has already been performed in the present invention, all of these values may be set to 1 (step S265).

What has been described above is just one embodiment for implementing the silicon crystal growth control apparatus using the image binarization according to the present invention, the present invention is not limited to the above embodiment, as claimed in the following claims As described above, any person having ordinary knowledge in the field of the present invention without departing from the gist of the present invention has the technical spirit of the present invention to the extent that various modifications can be made.

The present invention as described above has the effect of eliminating the ambiguity of the target tracking due to the reflected light by binarizing the configuration of the screen so that the camera can recognize by distinguishing the brightest part and the other part.

In addition, the present invention has an effect of allowing the user to easily operate and control the operation by providing a user interface that is convenient for the user to use.

1 is a view for explaining a problem according to the prior art.

2 is a block diagram of a crystal growth system using a silicon crystal growth control apparatus using binarization according to an embodiment of the present invention.

3 is a block diagram of a silicon crystal growth control apparatus according to an embodiment of the present invention.

FIG. 4 is a diagram for describing camera position setting of FIG. 2.

5 is a view showing an image obtained by the camera of FIG.

FIG. 6 is a view showing binarized images of images obtained by the camera of FIG. 2.

FIG. 7 is a diagram for describing a method of detecting an outermost edge from the binarized image of FIG. 6.

8 is a flowchart of a silicon crystal growth control method according to an embodiment of the present invention.

9 is a flowchart of an initialization operation of the silicon crystal growth control apparatus according to an embodiment of the present invention.

10A to 10G are diagrams used for initialization.

Claims (5)

A video image frame buffer installed in a chamber of a crystal growth system and receiving and storing an image from a camera that generates an image of a contact surface between a melt and a crystal including a solidification interface; An analog / digital converter for receiving and digitizing image data from the video image frame buffer; Receives and displays an image stored in the video image frame buffer, binarizes the received image using the stored threshold value, detects an edge, calculates the outermost edge, and calculates the diameter of the solidification interface using the converted value. Diameter measuring means for outputting; And And an analog output card which receives the diameter value calculated from the diameter measuring means, converts the analog value into a corresponding analog value, and outputs the analog value to a programmable logic controller of the crystal growth system. The method of claim 1, And the camera is a head detachable camera. The method of claim 1, The camera is a crystal growth control device, characterized in that installed 45 ° to 60 ° with respect to the vertical axis. The method of claim 1, The diameter measuring means scans an image stored in the video image frame buffer at predetermined time intervals, binarizes the scanned image, calculates the outermost edge, calculates the diameter of the solidification interface, and then calculates the diameter. And averaging the diameters of the solidified interfaces thus obtained and outputting the average values as diameters. The method according to any one of claims 1 to 4, The diameter measuring means, A display unit which displays an image received from the video image frame buffer and displays a binarized image; An input unit for receiving a user's request from an external user; A memory for storing the measured diameter, a threshold for binarizing the image, and a converted value for calculating the diameter of the solidification interface; And Receives an image stored in the video image frame buffer and displays it on the display, detects an edge after binarizing the received image using a threshold stored in the memory, calculates an outermost edge, and converts the image stored in the memory. And a control unit which calculates and outputs the diameter of the solidification interface using the value, and controls the display unit, the input unit, and the memory.