JP2000169288A - Automatic discrimination of single crystallization and device for producing semiconductor single crystal by utilization of the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for automatically discriminating single crystallization, enabling the automatic discrimination of the single crystallization of a semi-conductor crystal in a seed process by detecting the appearance of a seam line by the treatment of images, and to provide a semiconductor single crystal production device utilizing the method. SOLUTION: This semiconductor single crystal production device by CZ method comprises a CCD cameral 21 for photographing a seed crystal 1 and a fused liquid surface 2 in a crucible 11 through a through-window 20, a device 24 for automatically discriminating the single crystallization, and a control device 25 for pulling up the single crystal. The device 24 for automatically discriminating the single crystallization calculates a distance between a horizontal standard position line preliminarily set in the photographed image and used for measuring the distance and the lowest end of the meniscus of the semiconductor crystal in the image photographed with the CCD camera 21 by an image treating method, and detects as the appearance of the seam line showing single crystallization, when the measured distance is not larger than a preliminarily set threshold value. The control device 25 for pulling up the single crystal controls the automatic transfer of the treating process of the semiconductor single crystal production device from a seed process to a neck process according to the discrimination result of the device 24 for automatically discriminating the single crystallization.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic discrimination method for a semiconductor crystal in a seed step of a semiconductor single crystal manufacturing method by the CZ method (Czochralski method), and a semiconductor single crystal formed by using this method. The present invention relates to a crystal manufacturing apparatus.

[0002]

2. Description of the Related Art As an apparatus for producing a single crystal of a semiconductor such as silicon, an apparatus utilizing the CZ method is known. This CZ
In the method, a rod-shaped polycrystalline silicon is crushed and melted in a quartz glass crucible, and a seed crystal (seed) serving as a nucleus is immersed in the melt by suspending it with a wire and pulled up while slowly rotating the seed crystal. By doing so, a single crystal is grown from the tip of the seed crystal.

[0003] By the way, the process of pulling a single crystal in the CZ method is subdivided into a seed step of soaking a seed crystal in a melt to grow a single crystal from the tip of the seed crystal, and a subsequent step of seeding the single crystal. A neck process in which the crystal diameter is increased by a predetermined distance while narrowing the crystal diameter in order to eliminate dislocations, and a body process in which a large-diameter single crystal as a product is grown stably following the neck process. However, when shifting from the seed step to the neck step, it is necessary to accurately determine whether the single crystal has grown stably from the tip of the seed crystal in the seed step.

Conventionally, in order to determine whether a silicon crystal is to be single-crystallized in order to shift from the seeding process to the necking process, an operator looks into the crucible from a see-through window and places a seam line (crystal habit) unique to the single crystal on the crystal surface. Line) appeared by visually checking.

FIGS. 15A and 15B show examples of images when the seam line appears and when it does not appear. In these figures, 1 is a seed crystal, 2 is a melt surface of polycrystalline silicon melted by heating, 3 is a meniscus of a silicon crystal grown from the tip of the seed crystal 1, and 4 is a seam line appearing on the crystal surface. . Conventionally, by visually confirming that a seam line 4 indicating single crystallization as shown in FIG. 15A has appeared on the crystal surface, manual control is performed so as to shift from the seed process to the neck process. I was Note that the number of seam lines appearing on the crystal surface is a unique number determined by the crystal orientation.

[0006]

However, in the conventional method for visually confirming the appearance of the seam line as described above, there are the following technical problems. (1) Visual confirmation places an extremely heavy burden on the operator. (2) It is difficult to automate the transition timing from the seed process to the neck process. (3) Since it takes time from the immersion of the seed crystal in the melt to the growth of the single crystal and the appearance of the seam line, it is necessary for the operator to monitor at regular intervals. (4) If the monitoring timing does not match, the seam line will be left as it is despite the appearance,
This leads to a decrease in throughput, an increase in power consumption, and deterioration of members.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned technical problems. By detecting the appearance of a seam line by image processing, it is possible to automatically determine whether a semiconductor crystal is single-crystallized in a seed step. An object of the present invention is to provide a method for automatically determining single crystallization and a semiconductor single crystal manufacturing apparatus configured by using the method.

[0008]

In order to solve the above-mentioned problems, a method for automatically determining single crystallization according to claim 1 of the present invention comprises:
In the method of manufacturing a semiconductor single crystal by the CZ method, when determining the single crystal growth of the grown crystal for shifting from the seed process to the neck process, the seed crystal and the melt surface are photographed by the imaging means, and the The distance between the set horizontal reference position line for distance measurement and the lowermost end of the meniscus of the semiconductor crystal photographed by the imaging means was calculated by image processing, and the distance became equal to or less than a preset threshold value. Sometimes, it is detected as the appearance of a seam line indicating single crystallization.

In such a configuration, the appearance of a seam line indicating single crystallization is automatically determined from a change in the distance between the horizontal reference position line set in the photographed image and the lowermost end of the meniscus of the semiconductor crystal. And it can be automatically determined whether or not the single crystallization of the semiconductor crystal has been achieved.

According to a second aspect of the present invention, in the method of manufacturing a semiconductor single crystal by the CZ method, the method for determining the single crystallization of a grown crystal for shifting from a seed step to a neck step is provided. The seed crystal and the melt surface portion are photographed by the imaging means, and an image of the seed crystal and the melt surface portion in a state where a seam line has appeared is prepared as a comparison pattern, and the seed crystal and the melt photographed by the imaging means are prepared. The appearance of a seam line indicating single crystallization is detected by performing pattern matching between a captured image of a surface portion and the comparison pattern.

With this configuration, the appearance of a seam line indicating single crystallization can be automatically detected by pattern matching between the seed crystal, the photographed image of the melt surface portion, and the comparison pattern. Can be automatically determined whether or not single crystallization has been achieved.

According to a third aspect of the present invention, in the method for manufacturing a semiconductor single crystal by the CZ method, the method for determining the single crystallization of a grown crystal for shifting from a seed process to a neck process is provided. The seed crystal and the melt surface portion are photographed by the imaging means, and the number of pixels of the meniscus portion of the semiconductor crystal in the photographed image of the seed crystal and the melt surface portion photographed by the imaging means is counted by image processing. When a predetermined threshold value is exceeded, it is detected as the appearance of a seam line indicating single crystallization.

With this configuration, the appearance of a seam line indicating single crystallization is automatically detected from a change in the number of pixels of the meniscus portion of the semiconductor crystal in the images of the seed crystal and the melt surface. It is possible to automatically determine whether or not single crystallization of the semiconductor crystal has been achieved.

According to a fourth aspect of the present invention, in the method of manufacturing a semiconductor single crystal by the CZ method, the method for determining single crystallization of a grown crystal for shifting from a seed step to a neck step is provided. The seed crystal and the melt surface are photographed by the imaging means, and a measurement line that crosses the meniscus part of the semiconductor crystal is previously set on the photographed image. Measure the change in luminance at the intersection of the contour line of the meniscus and the measurement line, and detect as the appearance of a seam line indicating single crystallization when the luminance change exceeds a predetermined threshold. It was done.

With this configuration, the appearance of a seam line indicating single crystallization can be automatically detected from a change in luminance at the intersection of the contour line of the meniscus and the measurement line, and the semiconductor crystal can be detected. Whether or not single crystallization has been achieved can be automatically determined.

According to a fifth aspect of the present invention, there is provided a semiconductor single crystal manufacturing apparatus according to the CZ method.
Imaging means for photographing the seed crystal and the melt surface portion in the crucible through the see-through window; a horizontal reference position line for distance measurement set in advance in the photographed image; The distance between the semiconductor crystal and the lowermost end of the meniscus is calculated by image processing, and when the distance becomes equal to or less than a predetermined threshold value, single crystallization is detected as the appearance of a seam line indicating single crystallization. An automatic discriminating apparatus and a control means for automatically shifting a processing step of a semiconductor single crystal manufacturing apparatus from a seed step to a neck step according to a discrimination result of the single crystallizing automatic discriminating apparatus are provided.

In such a configuration, the appearance of a seam line indicating single crystallization is automatically determined from a change in the distance between the horizontal reference position line set in the photographed image and the lowermost end of the meniscus of the semiconductor crystal. Thus, it is possible to obtain a semiconductor single crystal manufacturing apparatus capable of automatically determining whether or not single crystallization of a semiconductor crystal has been achieved and shifting from a seed process to a neck process.

According to a sixth aspect of the present invention, there is provided a semiconductor single crystal manufacturing apparatus according to the CZ method.
An imaging means for photographing the seed crystal and the melt surface portion in the crucible through the see-through window, and an image of the seed crystal and the melt surface portion in a state where the seam line has appeared in advance are prepared as a comparison pattern, and the imaging means A single crystallizing automatic discrimination device for detecting the appearance of a seam line indicating single crystallization by performing pattern matching between a photographed seed crystal, a photographed image of a melt surface portion, and the comparison pattern; The apparatus is provided with control means for automatically shifting the processing steps of the semiconductor single crystal manufacturing apparatus from the seed step to the neck step in accordance with the determination result of the apparatus.

In such a configuration, the appearance of a seam line indicating single crystallization can be automatically detected by pattern matching between the photographed image of the seed crystal and the melt surface portion and the comparison pattern. It is possible to obtain a semiconductor single crystal manufacturing apparatus capable of automatically determining whether or not single crystallization has been achieved and shifting from the seed step to the neck step.

According to a seventh aspect of the present invention, there is provided a semiconductor single crystal manufacturing apparatus according to the CZ method.
Imaging means for photographing the seed crystal and the melt surface in the crucible through the see-through window; and image processing the number of pixels of the meniscus portion of the semiconductor crystal in the photographed image of the seed crystal and the melt surface taken by the imaging means. A single crystallizing automatic discriminating device for counting and detecting as the appearance of a seam line indicating single crystallizing when the number of pixels exceeds a predetermined threshold value; and a semiconductor unit according to the discrimination result of the single crystallizing automatic discriminating device. The apparatus is provided with control means for automatically shifting the processing steps of the crystal manufacturing apparatus from the seed step to the neck step.

With this configuration, the appearance of a seam line indicating single crystallization is automatically detected from a change in the number of pixels in the meniscus portion of the semiconductor crystal in the images of the seed crystal and the melt surface. Accordingly, it is possible to obtain a semiconductor single crystal manufacturing apparatus capable of automatically determining whether or not single crystallization of a semiconductor crystal has been achieved and shifting from a seed process to a neck process.

According to the present invention, there is provided a semiconductor single crystal manufacturing apparatus according to the CZ method.
An imaging means for photographing the seed crystal and the melt surface in the crucible through the see-through window, and a measurement line crossing the meniscus portion of the semiconductor crystal are set on the photographed image in advance, and the seed crystal and the melt photographed by the imaging means are set. A change in luminance at an intersection point where the contour line of the meniscus in the photographed image of the liquid surface portion and the measurement line intersect is measured, and a seam line indicating single crystallization when the luminance change exceeds a predetermined threshold value And a control means for automatically shifting a processing step of the semiconductor single crystal manufacturing apparatus from a seed step to a neck step in accordance with a result of the discrimination of the single crystallizing automatic discriminating apparatus. It is composed.

With such a configuration, the appearance of a seam line indicating single crystallization can be automatically detected from a change in luminance at the intersection of the contour line of the meniscus and the measurement line, and the semiconductor crystal can be detected. It is possible to obtain a semiconductor single crystal manufacturing apparatus capable of automatically determining whether or not single crystallization has been achieved and shifting from the seed step to the neck step.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. [First Embodiment] FIGS. 1 to 5 show a first embodiment of a silicon single crystal manufacturing apparatus to which the present invention is applied. FIG. 1 is an overall configuration diagram of a silicon single crystal manufacturing apparatus,
2 is a diagram showing an example of the circuit configuration of the single crystallizing automatic discriminating apparatus in FIG. 1, FIG. 3 is a diagram showing a monitor screen for explaining the operation, FIG. 4 is a waveform diagram for explaining the operation, and FIG. FIG. 7 is a diagram illustrating a change characteristic of a distance from a lower edge of a monitor screen to a lowermost end of a meniscus of a silicon crystal.

In the first embodiment, as shown in FIG. 3, a monitor screen 26 in which the seed crystal 1 and the melt surface 2 are photographed.
The distance L between the lower edge of the upper screen and the lowermost edge of the meniscus 3 of the silicon crystal is calculated by image processing, and when this distance L becomes equal to or less than a preset threshold value,
This is detected as the appearance of a seam line 4 indicating single crystallization. In the first embodiment, the horizontal reference position line for measuring the distance L is set at the lower edge of the monitor screen 26. However, if the horizontal reference position line is below the meniscus 3, May be set at any position on the monitor screen.

In FIG. 1, 11 is a crucible made of quartz glass, 12 is a heater made of graphite disposed around the crucible, 13
The crucible rotating mechanism 14 is a crucible lifting mechanism.

The crucible 11 is surrounded by a vacuum vessel 15, and a seed crystal elevating mechanism 16 composed of a motor, a hoisting drum and the like is installed at the upper end of the neck of the vacuum vessel 15. A seed chuck 18 for holding the seed crystal 1 is attached to the end of the connected stainless steel wire 17. A seed crystal rotating mechanism 19 is provided below the seed crystal elevating mechanism 16.
The seed crystal 1 suspended at the tip of the wire 17 can be rotated by rotating the whole 6.

A transparent window 20 made of transparent quartz glass is formed at the shoulder of the vacuum vessel 15, and a CCD is provided in this window.
An imaging unit such as a camera 21 is provided facing the crucible 11. The CCD camera 21 obtains a photographed image as shown in FIG. 3 by photographing the portion of the seed crystal 1 and the melt surface 2 from obliquely above when pulling up the silicon single crystal.

Reference numeral 22 denotes a camera control unit, and 23 denotes a CCD.
A monitoring television monitor 24 for displaying an image captured by the camera 21; a single crystal 24 for detecting the appearance of a seam line indicating single crystallization by image processing from an image captured by the CCD camera 21 transmitted via the camera control unit 22 An automatic discrimination device 25 controls the operation of the crucible rotating mechanism 13, the crucible elevating mechanism 14, the seed crystal elevating mechanism 16, the seed crystal rotating mechanism 19, the temperature control of the heater 12, and the like according to the discrimination result of the single crystallizing automatic discriminating device 24. This is a single crystal pulling control device for performing comprehensively.

The single crystallizing automatic discriminating apparatus 24 has a circuit configuration as shown in FIG. That is, in FIG.
Reference numeral 241 denotes a comparator for pulsating a video signal sent from the CCD camera 21 at a predetermined threshold value V _S and outputting the pulse signal. Reference numeral 242 denotes a pulse width discrimination circuit for removing a pulse signal having a predetermined pulse width or less to remove noise. Reference numeral 243 denotes an H signal extraction circuit that extracts a horizontal synchronization signal (H signal) from a video signal, 244 denotes a V signal extraction circuit that extracts a vertical synchronization signal (V signal) from a video signal, and 245 denotes an H signal extraction circuit. H counting output H signal pulses
Signal pulse counter, 246 is a horizontal scan line counter for detecting the position of the horizontal scanning line l _n corresponding to the screen bottom edge of the monitor screen 26 (see FIG. 3) by counting the number of horizontal scanning lines, 247 V signals A delay circuit for slightly delaying the V signal pulse output from the extraction circuit 244,
48 is an OR circuit.

249 is an H signal pulse counter 24
5 is a count value hold circuit that reads out and temporarily holds the H signal count value, 250 is an average value calculation circuit that calculates the average value of the H signal count values for each rotation of the silicon crystal to eliminate a detection error, and 251 is the average value. Value calculation circuit 250
The distance L between the lower edge of the monitor screen 26 and the lowermost edge of the silicon crystal meniscus 3 is calculated from the averaged H signal count value output from This is a determination circuit for determining that the seam line 4 indicating single crystallization has appeared on the crystal surface when the threshold value L ₀ or less has been reached.

Next, the operation of detecting the seam line 4 in the first embodiment having the above configuration will be described. First,
The rod-shaped polycrystalline silicon as a raw material is put into a crucible 11 crushed in a block shape, and is melted by being heated by a heater 12. The seed crystal 1 is held by the seed chuck 18 at the tip of the wire 17 and suspended in the crucible 11.

When the production of the silicon single crystal is started in this state, the wire 17 is lowered downward by the seed crystal elevating mechanism 16, and the tip of the seed crystal 1 suspended at the tip of the wire 17 is moved to the crucible 11. The seed crystal 1 and the crucible 11 are immersed in the melt surface 2 of the polycrystal silicon therein, and the drive of the seed crystal rotation mechanism 19 and the crucible rotation mechanism 13 is started.
Starts rotating slowly at a predetermined speed in the opposite direction or in the same direction. Thereby, a seed process is started.

The CCD camera 21 takes an image of the seed crystal 1 and the melt surface 2 through the see-through window 20, and the video signal is sent to the camera control unit 22 to form a monitor screen 26 as shown in FIG. TV monitor 23 for monitoring
And sent to the single crystallizing automatic discriminating device 24.

FIG. 4A shows an example of the waveform of the video signal sent from the CCD camera 21. In this video signal, H is a horizontal synchronizing signal (H signal), V is a vertical synchronizing signal (V signal) appearing every 1/60 second, and the horizontal scanning lines l _{1 to} l _{3 in FIG.} , L _n are the monitor screens 26 of FIG.
It assumed to correspond to the horizontal scanning lines l ₁ ~l _3, l _n in.

As is apparent from the monitor screen 26 of FIG. 3, when the seam line 4 appears on the surface of the meniscus 3 of the silicon crystal, the seam line 4 protrudes below the screen. The distance L between the lower edge of the screen and the lowermost edge of the meniscus 3 of the silicon crystal becomes smaller by that amount. Therefore, by monitoring this distance L, it is possible to detect whether or not the seam line 4 indicating single crystallization has appeared. The single crystallizing automatic discriminating device 24 shown in FIG. 2 obtains the distance L by image processing, and when the value becomes smaller than a predetermined threshold value L ₀ , a seam line 4 indicating single crystallization appears. This is detected as having been performed.

That is, the video signal sent from the CCD camera 21 is input to the comparator 241, the H signal extraction circuit 243, and the V signal extraction circuit 244 of the automatic single crystallizing discriminator 24 shown in FIG. The comparator 241, FIG. 4 determines the signal level at a predetermined threshold value V _S as shown in (a), 1 signal portion equal to or greater than the threshold value V _S as shown in FIG. 4 (b), the threshold value The signal portion below V _S is converted to 0 and output.

The output pulse of the comparator 241 is sent to a pulse width discriminating circuit 242, and after removing a pulse signal having a pulse width equal to or less than a predetermined pulse width as a noise, it is sent to a reset terminal R of an H signal pulse counter 245 via an OR circuit 248. , H signal pulse counter 245 is reset.

On the other hand, the H signal extraction circuit 243 extracts the H signal (see FIG. 4A) from the video signal, generates an H signal pulse, and counts the H signal pulse counter 245 and the horizontal scanning line counter 246. Send to terminal C. The H signal pulse counter 245 counts this H signal pulse each time it arrives. On the other hand, the horizontal scanning line counter 246
Continue counting the signal pulses, to generate an output pulse when a match with the scanning line number N of the scanning lines l _n corresponding to the screen bottom edge of the monitor screen 26 in which the count value is set in advance.

[0040] As apparent from the above operation, to the position of the horizontal scanning line l ₃ intersects the seam line 4 from the top of the screen position on the monitor screen 26 of FIG. 3, from the comparator 241 as FIG. 4 (b) always the pulse is output, H signal pulse counter 245 continues to be reset by this pulse, until it reaches the position of the horizontal scanning line l ₃ has a count value is always 0.

[0041] When the scanning position has passed the position of the horizontal scanning line l _3, since the horizontal scanning lines is only across the melt surface 2 of the portion of the polycrystalline silicon, the comparator 241 in FIG. 4 (b) As shown, no pulse is output.
Thus, no longer applied reset the H signal pulse counter 245, the H signal pulse counter 245 sequentially counts the H signal pulses of the horizontal scanning line l ₃ and later.

On the other hand, the horizontal scanning line counter 246 counts the H signal pulses output from the H signal extracting circuit 243 and sequentially counts the number of horizontal scanning lines of the video signal, and the count value is set in advance. corresponding to previously lower end position of the monitor screen 26 and coincides with the scanning line number n of horizontal scanning lines l _n generates an output pulse. by this,
The counting operation of the H signal pulse counter 245 is stopped.

Therefore, the count value of the H signal pulse counter 245 at the time when the counting operation is stopped by the output pulse of the horizontal scanning line counter 246 is as shown in FIG.
Shows the total number of horizontal scanning lines included between the horizontal scanning line l ₃ position in the monitor screen 26 to the horizontal scanning line l _n corresponding to the screen bottom edge. And the CCD camera 21
The video signal sent from 1 field is 1/60
Sec, since a television signal of one frame 1/30 second, the count value of the H signal pulse counter 245 indirectly the distance L from the horizontal scanning line l ₃ in the monitor screen 26 of FIG. 3 until the screen lower edge It will represent.

When horizontal scanning for one screen is completed and a V signal for vertical synchronization is sent in the video signal as shown in FIG. 4A, the V signal extraction circuit 244 extracts this signal. , V signal pulse. The count value hold circuit 249 reads out the count value of the H signal pulse counter 245 by the V signal pulse, and temporarily stores and holds the count value. Further, the V signal pulse is supplied to the delay circuit 247.
Then, the signal is sent to the reset terminal R of the H signal pulse counter 245 via the OR circuit 248 to reset the H signal pulse counter 245 and return its count value to zero.

The H signal pulse counter 245 repeats the above operation for each screen of the video signal sent from the CCD camera 21. Each time, the H signal pulse counter 245 starts from the lower edge of the monitor screen 26 to the lowermost edge of the meniscus 3 of the silicon crystal. Is output as the number of horizontal scanning lines.

The seed crystal 1 suspended on the wire 17 is slowly rotated at a predetermined rotation speed by the seed crystal rotating mechanism 19. For this reason, the position of the seam line 4 on the monitor screen 26 in FIG. Therefore, the distance L from the lower edge of the monitor screen 26 to the seam line 4 changes according to the rotational position of the seam line 4 and pulsates. Therefore, in order to prevent such erroneous detection due to the rotation, the average value per rotation of the seed crystal 1 is calculated by the average value calculation circuit 250, and this average value is set as the measurement distance L, and the distance determination circuit 251 in the subsequent stage is used. Send to

The distance determination circuit 251 is provided with an average value calculation circuit 2
It compares the number of horizontal scanning line for providing a measurement distance L sent from 50, and the number of horizontal scanning line for providing a prescribed distance L ₀ which is set in advance, for example, as shown in FIG. 5, is measured T ₁ when the distance L becomes smaller than the threshold distance L ₀
At this point, it is determined that the seam line 4 indicating single crystallization has appeared, and a detection output of the seam line is generated. Then, this detection output is sent to the single crystal pulling control device 25 of FIG.

Upon receiving the seam wire detection output, the single crystal pulling control device 25 controls the operations of the crucible rotating mechanism 13, the crucible elevating mechanism 14, the seed crystal elevating mechanism 16, and the seed crystal rotating mechanism 19, and performs a seeding process. Automatically shifts from the process to the neck process.

As described above, in the case of the first embodiment, the distance L between the lower edge of the monitor screen 26 and the lowermost edge of the silicon crystal meniscus 3 is calculated by image processing. L seam line 4 to generate the detection output is determined that those appearing when it becomes smaller than the predetermined distance L _0. For this reason, it is possible to automatically detect whether or not the silicon crystal has been single-crystallized, and to control the silicon single-crystal manufacturing apparatus using the detection result, thereby automating the transition from the seed process to the neck process. can do.

It should be noted that the above monitoring is continued even after the single crystallization is once achieved. For example, as shown at time t _{2 in} FIG. 5, the distance L between the lower edge of the monitor screen 26 and the seam line 4 is reduced. it is desirable that when a longer than a prescribed distance L ₀ is configured to issue an alarm as a single crystallization is destroyed.

[Second Embodiment] FIG. 6 shows a second example of the structure of an automatic single-crystallizing discriminating apparatus 24 for the second embodiment. The overall configuration of the silicon single crystal manufacturing apparatus is the same as that shown in FIG.

In the second embodiment, as shown in FIG. 7, a photographed image of the seed crystal 1 and a portion of the melt surface 2 where a seam line indicating single crystallization appears beforehand is used as a comparison pattern P. By preparing a pattern matching between the comparative pattern P and an image of the seed crystal 1 and the melt surface 2 taken by the CCD camera 21, whether or not the seam line 4 indicating single crystallization has appeared is prepared. Is to be detected.

In FIG. 6, reference numeral 261 denotes the CCD camera 21.
262 is a frame image storage unit that stores one frame of the captured image converted to a binary image, and 263 is a criterion for the appearance of seam lines. A comparison pattern storage unit 264 in which a comparison pattern P as shown in FIG. 7 is stored in advance is used for pattern matching between the captured image stored in the frame image storage unit 262 and the comparison pattern P stored in the comparison pattern storage unit 263. And a pattern matching unit that detects the appearance of a seam line when both patterns match.

Next, the operation of the single crystallizing automatic discriminating apparatus 24 shown in FIG. 6 will be described. A video signal captured by the CCD camera 21 is converted into a binary image by a binarization circuit 261 and sent to a frame image storage unit 262. Frame image storage unit 2
Reference numeral 62 stores and stores an image of one frame of the seed crystal 1 and the melt surface 2 as shown in FIG.

The 2 stored in the frame image storage unit 262
The captured image composed of the value image is
4 and is subjected to pattern matching with a comparative pattern P prepared in advance as shown in FIG. When the two patterns match, a seam line 4 is added to the silicon crystal.
Is detected, a detection output of the seam wire 4 is generated and sent to the single crystal pulling control device 25 of FIG.

Upon receiving the seam wire detection output, the single crystal pulling control device 25 controls the operations of the crucible rotating mechanism 13, the crucible elevating mechanism 14, the seed crystal elevating mechanism 16, and the seed crystal rotating mechanism 19, and performs a seeding process. Automatically shifts from the process to the neck process.

As described above, in the case of the second embodiment, the appearance of the seam line 4 is detected by pattern matching between the photographed image and the comparison pattern. For this reason, it is possible to automatically detect whether or not the silicon crystal has been single-crystallized, and to control the silicon single-crystal manufacturing apparatus using the detection result, thereby automating the transition from the seed process to the neck process. can do.

In the example of FIG. 6, for simplicity of explanation, a case where a photographed image is converted into a binary image is exemplified. However, instead of the binarization circuit 261, a multi-valued circuit is used. The image may be converted to a ternary or higher-valued multi-valued image. When converted to a multi-valued image, it takes time to perform pattern matching, but the detection accuracy is improved accordingly.

Also in the case of the second embodiment, the above-mentioned monitoring is continued even after the single crystallization is once achieved.
It is desirable to configure so that when the result of pattern matching does not match, an alarm is issued as single crystallization is broken.

[Third Embodiment] FIG. 9 shows a third configuration example of an automatic single-crystallizing discrimination device 24 for the third embodiment. The overall configuration of the silicon single crystal manufacturing apparatus is the same as that shown in FIG.

In the third embodiment, as shown in FIG. 10, a monitor screen 2 in which a seed crystal 1 and a melt surface 2 are photographed.
In 6, the total number of pixels in the meniscus 3 of the silicon crystal and the seam line 4 indicated by hatching is counted, and when the number of pixels exceeds a predetermined threshold value, the appearance of the seam line 4 is detected. Things.

In FIG. 9, reference numeral 271 denotes a multi-value conversion circuit for converting a video signal into a multi-valued image, and 272, an image analysis of the multi-valued image, and each of a seed crystal 1, a melt surface 2, a meniscus 3 and a seam line 4. An image area separating unit 273 for separating the image into parts is a pixel number counting unit for counting the number of pixels of the separated meniscus 3 and the seam line 4 and a number 274 compares the counted number of pixels with a preset threshold value. This is a pixel number comparison unit that detects the appearance of the seam line 4.

Next, the operation of the single crystallizing automatic discriminating apparatus 24 shown in FIG. 9 will be described. A video signal photographed by the CCD camera 21 is converted into a multi-valued image by a multi-value conversion circuit 271 and sent to an image area separation unit 272. The image area separation unit 272
The sent multi-valued image is subjected to image analysis using various characteristics such as a luminance difference and a color difference, and is divided into respective regions of a seed crystal 1, a melt surface 2, a meniscus 3 and a seam line 4. This segmentation result is sent to the pixel number counting unit 273. Pixel counting section 273
Calculates the number of pixels included in the meniscus 3 and the seam line 4 indicated by hatching in FIG. 10 using the region separation result, and sends the result to the pixel number comparison unit 274.

The number-of-pixels comparing section 274 compares the number of transmitted pixels with a preset threshold value, and when the number of transmitted pixels is larger than the threshold value, the portion where the seam line 4 appears. And a detection output of the seam line is generated. That is, in FIG. 10, when the seam line 4 appears, the area of the hatched portion is increased by an amount corresponding to the appearance of the seam line 4 and protruding outward, and the number of pixels is increased by that much. Become. Accordingly, the change in the number of pixels when the seam line 4 appears and when it does not appear is, for example, as shown in FIG. 11, and the dotted line C without the seam line and the solid line D with the seam line are different. If the threshold value of the pixel number comparison unit 274 is set per intermediate position, the appearance of the seam line 4 can be detected from a change in the number of pixels.

The detection output of the seam line output from the pixel number comparing section 274 is sent to the single crystal pulling control device 25 of FIG. When the single crystal pulling control device 25 receives the seam wire detection output, the crucible rotation mechanism 13,
The operations of the crucible raising / lowering mechanism 14, the seed crystal raising / lowering mechanism 16, and the seed crystal rotating mechanism 19 are controlled, and the processing is automatically shifted from the seeding step to the neck step.

As described above, in the case of the third embodiment, the appearance of the seam line 4 is detected from the change in the number of pixels of the captured image. For this reason, it is possible to automatically detect whether or not the silicon crystal has been single-crystallized, and to control the silicon single-crystal manufacturing apparatus using the detection result, thereby automating the transition from the seed process to the neck process. can do.

In the case of the third embodiment as well, the above monitoring is continued even after the single crystallization is once achieved.
When the number of pixels becomes equal to or less than the threshold value, it is preferable to issue a warning that single crystallization is broken.

[Fourth Embodiment] FIG. 12 shows a fourth embodiment of the single crystallizing automatic discriminating apparatus 24 used in the third embodiment.
An example of the configuration will be described. The overall configuration of the silicon single crystal manufacturing apparatus is the same as that shown in FIG.

In the fourth embodiment, as shown in FIG. 13, a measurement line E crossing the meniscus 3 portion of the silicon crystal is previously set on the photographed image, and the measurement line E and the outer periphery of the meniscus 3 are set. A change in luminance at the intersection P where the line intersects is measured, and the appearance of the seam line 4 is detected from the change.

That is, when the change in luminance at the intersection point P where the measurement line E and the outline of the meniscus 3 intersect is measured for the rotating single crystal, when the seam line 4 indicating single crystallization appears, As shown in FIG. 14, each time the seam line 4 intersects the photometry line E, the peak luminance Bmax
Occurs. Therefore, by detecting the peak luminance Bmax, the appearance of the seam line 4 indicating single crystallization can be detected.

In FIG. 12, reference numeral 281 denotes a luminance measuring circuit for measuring the luminance at the intersection P where the measuring line E and the outer line of the meniscus 3 intersect, and 282 denotes the peak luminance Bmax
283 is a peak luminance detection circuit for detecting
A luminance difference calculating circuit 284 for calculating a luminance difference ΔB between max and the base luminance B detects a luminance difference as an appearance of a seam line 4 indicating single crystallization when the luminance difference ΔB exceeds a predetermined threshold value. Circuit.

Next, the single crystallizing automatic discriminating device 24 shown in FIG.
Will be described. The video signal photographed by the CCD camera 21 is sent to the intersection position luminance measuring circuit 281, and FIG.
Is measured at the intersection P as shown in FIG. The peak luminance detecting circuit 282 detects the peak luminance Bmax from the measured luminance and sends it to the luminance difference calculating circuit 283.

The luminance difference calculation circuit 283 calculates the peak luminance Bma
The luminance difference ΔB between x and the base luminance B is calculated and sent to the luminance difference determination circuit 284. The luminance difference determination circuit 284 calculates the luminance difference Δ
B is compared with a predetermined threshold value. When B exceeds the threshold value, it is determined that the seam line 4 indicating single crystallization has appeared, and a seam line detection output is generated. This detection output is sent to the single crystal pulling control device 25 of FIG.

Then, the single crystal pulling control device 2 shown in FIG.
5 is a crucible rotating mechanism 13, a crucible elevating mechanism 14, and a seed crystal elevating mechanism 1 when the detection output of the seam wire is received.
6. The operation of the seed crystal rotating mechanism 19 is controlled, and the processing is automatically shifted from the seeding step to the neck step.

As described above, in the case of the fourth embodiment, the appearance of the seam line is detected from the change in luminance at the intersection point where the measurement line and the contour line of the meniscus intersect. For this reason, it is possible to automatically detect whether or not the silicon crystal has been single-crystallized, and to control the silicon single-crystal manufacturing apparatus using the detection result, thereby automating the transition from the seed process to the neck process. can do.

In the case of the fourth embodiment as well, the above monitoring is continued even after the single crystallization is once achieved.
When the luminance difference becomes equal to or less than the threshold value, it is desirable to issue a warning that single crystallization is broken.

[0077]

As described above, according to the first aspect of the present invention,
According to the invention described above, the appearance of a seam line indicating single crystallization can be detected from a change in the distance between the horizontal reference position line set in the captured image and the lowermost end of the meniscus of the semiconductor crystal. This eliminates the need for the operator to visually check the occurrence of the seam line unlike the related art, thereby reducing the burden on the operator. In addition, it is possible to automate the transition timing from the seed process to the neck process, and because the monitoring timing does not match as in the case of visual confirmation, the confirmation of the appearance of the seam line is delayed, the throughput is reduced, and the power consumption is reduced. It is possible to prevent the increase in the amount and the deterioration of the members.

According to the second aspect of the present invention, the appearance of a seam line indicating single crystallization can be detected by pattern matching between a photographed image of a seed crystal, a melt surface portion, and a comparison pattern. Therefore, the same effect as the first aspect of the invention can be obtained.

According to the third aspect of the present invention, the appearance of a seam line indicating single crystallization is detected from a change in the number of pixels of the meniscus portion of the semiconductor crystal in the images of the seed crystal and the melt surface. Therefore, the same effect as that of the first aspect can be obtained.

According to the invention described in claim 4 of the present invention, it is possible to detect the appearance of a seam line indicating single crystallization from a change in luminance at an intersection point where the outline of the meniscus of the semiconductor crystal and the measurement line intersect. Therefore, the same effect as that of the first aspect can be obtained.

According to the fifth aspect of the present invention, a seam line indicating single crystallization is obtained from a change in the distance between the horizontal reference position line set in the photographed image and the lowermost end of the meniscus of the semiconductor crystal. Can be obtained, and a single crystal manufacturing apparatus capable of automating the transition from the seed step to the neck step can be obtained. This eliminates the need for the operator to visually check the appearance of the seam line as in the related art, and can automate the transition timing from the seed process to the neck process, and can perform monitoring as in the case of the visual check. Since the timing does not match, the appearance of the seam line is delayed, so that a decrease in throughput, an increase in power consumption, and deterioration of members can be prevented. A crystal manufacturing apparatus can be provided.

According to the invention of claim 6 of the present invention, the appearance of a seam line indicating single crystallization is detected by pattern matching between the photographed image of the seed crystal and the melt surface part and the comparison pattern, and the seeding step is performed. A single crystal manufacturing apparatus capable of automating the transition to the neck step can be obtained. Therefore, the same effect as that of the fifth aspect can be obtained.

According to the seventh aspect of the present invention, the appearance of a seam line indicating single crystallization is detected from a change in the number of pixels of the meniscus portion of the semiconductor crystal in the images of the seed crystal and the melt surface. In addition, it is possible to obtain a semiconductor single crystal manufacturing apparatus that can automate the transition from the seed step to the neck step. Therefore, the same effect as that of the fifth aspect can be obtained.

According to the invention of claim 8 of the present invention, the appearance of a seam line indicating single crystallization is detected from a change in luminance at the intersection of the contour line of the meniscus of the semiconductor crystal and the measurement line, and seeding is performed. A semiconductor single crystal manufacturing apparatus capable of automating the transition from the process to the neck process can be obtained. Therefore, the same effect as that of the fifth aspect can be obtained.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing a first embodiment of a silicon single crystal manufacturing apparatus configured by applying the present invention.

FIG. 2 is a diagram showing an example of a circuit configuration of the single-crystallizing automatic discriminating apparatus in FIG. 1;

FIG. 3 is a diagram illustrating a monitor screen for explaining an operation according to the first embodiment;

FIG. 4 is a waveform chart for explaining the operation of the automatic single-crystallizing discriminating apparatus of FIG. 2;

FIG. 5 is a diagram illustrating a change characteristic of a distance from a lower edge of the monitor screen to a lowermost edge of a meniscus of a silicon crystal;

FIG. 6 is a diagram illustrating a circuit configuration example of a single-crystallizing automatic discriminating apparatus used in a second embodiment;

FIG. 7 is a diagram illustrating an example of a comparison pattern.

FIG. 8 is a diagram illustrating a monitor screen for explaining an operation according to the second embodiment;

FIG. 9 is a diagram illustrating an example of a circuit configuration of a single-crystallizing automatic discrimination device used in a third embodiment.

FIG. 10 is a diagram illustrating a monitor screen for explaining an operation according to the second embodiment;

FIG. 11 is a diagram illustrating a change characteristic of the number of pixels in a meniscus portion of a silicon crystal.

FIG. 12 is a diagram illustrating an example of a circuit configuration of a single crystallization automatic discrimination device used in a fourth embodiment.

FIG. 13 is a diagram illustrating a monitor screen for explaining an operation according to the fourth embodiment;

FIG. 14 is a diagram illustrating an example of a change state of luminance at an intersection point where an interface between a semiconductor crystal and a melt surface intersects a measurement line.

FIGS. 15A and 15B show an example of a photographed image of a seed crystal and a melt surface portion. FIG. 15A is a diagram showing an example of a photographed image when a seam line appears, and FIG. FIG. 10 is a diagram illustrating an example of a captured image in a case where does not appear.

[Description of Signs] 1 seed crystal 2 melt surface 3 meniscus 4 seam line 11 crucible 16 seed crystal raising / lowering mechanism 17 wire 18 seed chuck 19 seed crystal rotating mechanism 20 see-through window 21 CCD camera (imaging means) 22 camera control unit 23 television Monitor 24 Single crystallizing automatic discrimination device 25 Single crystal pulling control device (control means)

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yasuyuki Iwata 30 Soya, Hadano-shi, Kanagawa F-term in Toshiba Ceramics Development Co., Ltd. F-term (reference) 4G077 AA02 BA04 CF10 PF09

Claims (8)

[Claims] In a method of manufacturing a semiconductor single crystal by a CZ method, a seed crystal and a melt surface portion are photographed by an imaging means when a single crystal of a grown crystal is determined for shifting from a seed process to a neck process. The distance between the horizontal reference position line for measuring the distance previously set in the photographed image and the lowermost end of the meniscus of the semiconductor crystal photographed by the imaging means is calculated by image processing, and the distance is set at a predetermined threshold. A single crystallizing automatic discrimination method, characterized in that when the value becomes equal to or less than a value, it is detected as the appearance of a seam line indicating single crystallization. 2. A method of manufacturing a semiconductor single crystal by a CZ method, wherein when determining whether a single crystal of a grown crystal is to be shifted from a seed step to a neck step, a seed crystal and a melt surface part are photographed by an imaging means; An image of the seed crystal and the melt surface portion in a state where the seam line has appeared in advance is prepared as a comparison pattern, and pattern matching between the image of the seed crystal and the melt surface portion photographed by the imaging means and the comparison pattern is performed. A single crystallizing automatic discrimination method characterized by detecting the appearance of a seam line indicating single crystallization by performing the method. 3. A method for producing a semiconductor single crystal by the CZ method, wherein when determining single crystallization of a grown crystal for shifting from a seed step to a neck step, a seed crystal and a melt surface portion are photographed by an imaging means; The number of pixels in the meniscus portion of the semiconductor crystal in the images of the seed crystal and the melt surface taken by the imaging means is counted by image processing, and when the number of pixels exceeds a predetermined threshold, single crystallization is performed. A single crystallizing automatic discrimination method characterized by detecting the appearance of the indicated seam line. 4. A method of manufacturing a semiconductor single crystal by a CZ method, wherein, when determining single crystallization of a grown crystal for shifting from a seed step to a neck step, a seed crystal and a melt surface portion are photographed by an imaging means; A measurement line crossing the meniscus portion of the semiconductor crystal is set in advance on the photographed image, and an intersection point where the contour line of the meniscus in the photographed image of the melt surface portion and the seed crystal photographed by the imaging means intersects with the measurement line Measuring the change in luminance at step (b), and detecting the appearance of a seam line indicating single crystallization when the change in luminance exceeds a predetermined threshold value. 5. An apparatus for manufacturing a semiconductor single crystal by a CZ method, comprising: an imaging means for photographing a seed crystal and a melt surface portion in a crucible through a see-through window; and a distance measuring means set in a photographed image in advance. When the distance between the horizontal reference position line and the lowermost end of the meniscus of the semiconductor crystal in the image captured by the imaging unit is calculated by image processing, and when the distance becomes equal to or less than a predetermined threshold value, A single-crystallizing automatic discriminator for detecting the appearance of a seam line indicating single-crystallization, and a processing step of a semiconductor single-crystal manufacturing apparatus is automatically shifted from a seed process to a neck process according to the discrimination result of the single-crystallizing automatic discriminator. An apparatus for producing a semiconductor single crystal, comprising a control means for causing a semiconductor device to produce a single crystal. 6. An apparatus for producing a semiconductor single crystal by a CZ method, wherein: an imaging means for photographing a seed crystal and a melt surface portion in a crucible through a see-through window; and a seed crystal and a melt surface portion in a state where a seam line has appeared in advance. Is prepared as a comparison pattern, and the appearance of a seam line indicating single crystallization is detected by performing pattern matching between the seed crystal photographed by the imaging means, the photographed image of the melt surface part, and the comparison pattern. And a control means for automatically shifting a processing step of a semiconductor single crystal manufacturing apparatus from a seed step to a neck step in accordance with a result of the discrimination by the single crystallizing automatic discriminating apparatus. Semiconductor single crystal manufacturing equipment. 7. An apparatus for producing a semiconductor single crystal by the CZ method, wherein: an imaging means for photographing a seed crystal and a melt surface portion in a crucible through a see-through window; and a photographing of the seed crystal and the melt surface part photographed by the imaging means. A single crystallizing automatic discrimination device which counts the number of pixels of a meniscus portion of a semiconductor crystal in an image by image processing and detects the appearance of a seam line indicating single crystallization when the number of pixels exceeds a predetermined threshold value And a control means for automatically shifting a processing step of the semiconductor single crystal manufacturing apparatus from a seed step to a neck step in accordance with a determination result of the single crystallizing automatic determination apparatus. 8. An apparatus for manufacturing a semiconductor single crystal by a CZ method, comprising: an imaging means for photographing a seed crystal and a melt surface portion in a crucible through a see-through window; and a measuring line previously crossing a meniscus portion of the semiconductor crystal on a photographed image. It is set, and a change in luminance at an intersection point where the contour line of the meniscus and the measurement line in the photographed image of the seed crystal and the melt surface portion photographed by the imaging unit intersect is measured, and the luminance change is a predetermined value. A single crystallizing automatic discriminating device for detecting as the appearance of a seam line indicating single crystallizing when a threshold value is exceeded, and a seeding process for a semiconductor single crystal manufacturing device according to a discrimination result of the single crystallizing automatic discriminating device. A semiconductor single crystal manufacturing apparatus characterized by comprising control means for automatically shifting from a step to a neck step.