JP2009196830A - Apparatus for manufacturing deposited plate and method for manufacturing deposited plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for manufacturing a deposited plate and a method for manufacturing a deposited plate, by which adverse influences on the productivity by a substance that interferes with a dipping track into the melt of a cooling material in a melt. <P>SOLUTION: When a radiation thermometer 50 detects a surface temperature of a melt 23, a controlling device 45 determines whether a substance is present or not that interferes with a dipping track into the melt 23 of a cooling substrate 25 in the melt 23 based on changes in the surface temperature of the melt 23. Specifically, when a change in the surface temperature of the melt 23 is equal to or larger than a preliminarily determined change width and the state continues over a predetermined period, the controlling device 45 judges that a substance which interferes with the dipping track into the melt 23 of the cooling substrate 25 is present in the melt 23. When the controlling device 45 judges that a substance which interferes with the dipping track into the melt 23 of the cooling substrate 25 is present in the melt 23, the device stops dipping of the cooling substrate 25 into the melt 23. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a precipitation plate manufacturing apparatus and a precipitation plate manufacturing method.

  In the manufacture of a semiconductor element or the like, a process of forming a silicon layer is important. For example, such a silicon layer is obtained by cutting an ingot into small blocks with a band saw or the like, and further slicing with a wire saw or an inner peripheral blade method. There is a manufacturing method.

  Such a manufacturing method requires not only a casting process for obtaining a silicon ingot, but also a process of cutting into a predetermined block size and a slicing process that requires high cost. In this slicing process, a wire or an inner peripheral blade is cut. This is a major obstacle to reducing manufacturing costs, such as causing material loss that exceeds the thickness.

  As a conventional technique for solving such a problem, there has been proposed a method of manufacturing a silicon layer in which a slicing step is omitted, a cooling body substrate is immersed in molten silicon, and silicon is deposited and solidified and deposited on a generation surface of the cooling body. Yes.

  FIG. 6 is a diagram showing a simplified configuration of a deposition plate manufacturing apparatus 1 used for conventional silicon manufacturing, and FIG. 7 is a diagram for explaining an outline of silicon manufacturing in the deposition plate manufacturing apparatus 1. Hereinafter, a silicon manufacturing method in which a cooling body is immersed in molten silicon, and silicon is adhered and solidified and precipitated on the generation surface of the cooling body will be described with reference to FIGS.

  In the deposition plate manufacturing apparatus 1, a melting furnace 4 is disposed in a processing space 3 formed by a chamber 2. The melting furnace 4 is provided with a crucible 5, and a molten metal 6 obtained by heating and melting silicon is accommodated in the crucible 5. In the processing space 3, immersion means 8 for immersing the cooling body 7 in the molten metal 6 is provided.

  The dipping means 8 can hold the cooling body 7 carried into the processing space 3 through a cooling body carry-in port 9 formed on one side wall of the chamber 2 by a transfer device (not shown). The dipping means 8 conveys the cooling body 7 to be held in the direction indicated by an arrow 12, that is, from the vicinity of the cooling body carry-in port 9 to a position above the molten metal 6 accommodated in the crucible 5 and is immersed in the molten metal 6 to cool it. Silicon is solidified and deposited on the surface of the body 7. Thereafter, the dipping means 8 pulls the cooling body 7 and the silicon layer 11 formed on the surface of the cooling body 7 from the molten metal 6 and further moves away from the upper position of the molten metal 6, that is, in the direction indicated by the arrow 13. It conveys toward the cooling body carry-out port 10 formed in the side wall opposite to the one side wall in which the opening 9 is formed, and passes it through the cooling body carry-out port 10 to a conveyance device (not shown). The control device 14 controls the operation of each part of the deposition plate manufacturing apparatus 1.

  When the above series of silicon manufacturing operations are repeated a plurality of times, the amount of the molten metal 6 accommodated in the crucible 5 provided in the melting furnace 4 is reduced, and the manufacturing of the layered silicon 11 is disturbed. In this case, the production of the layered silicon 11 is temporarily stopped, and additional silicon is introduced from the outside of the precipitation plate manufacturing apparatus 1 into the crucible 5 and melted by a silicon melting material adding apparatus (not shown), and the molten metal for the reduced amount is melted. Replenish.

  In such a method used in the prior art, the cooling body 7 is immersed in the molten silicon melt 6 and then pulled out of the molten metal 6, so that the layered silicon 11 deposited on the surface of the cooling body 7 is deposited. And it is inevitable that large internal stress is included due to a rapid temperature change in the subsequent cooling process.

  When the size of the silicon layer is greater than a certain value, the large stress generated in the silicon layer deposited on the surface of the cooling body may destroy the silicon layer.

  In recent years, multi-cavity has become mainstream in order to improve manufacturing efficiency, and semiconductor devices and the like tend to be manufactured in as large a size as possible and then divided individually.

  Therefore, the silicon layer is also increased in size, and destruction due to internal stress becomes a serious problem.

  The precipitation plate manufacturing apparatus described in Patent Document 1 and Patent Document 2 is provided with falling object receiving means for receiving the falling object when the cooling body is pulled up after the precipitation and moving in the direction away from the crucible. Re-injected.

  In the single crystal growth apparatus described in Patent Document 3, a window having high light transmittance is formed at the center of the bottom of the container, an optical thermometer is faced to the window, and the detected optical signal is converted into an electrical signal to display the temperature. Like to do. When the melt is solidified, the temperature is lowered, and when the temperature is lowered, the heater output is increased to prevent the formation of solidified floating substances.

JP 2006-49439 A JP 2007-73635 A JP-A-10-167880

  In the precipitation plate manufacturing apparatus described in Patent Literatures 1 and 2, the fallen object that falls to the outside of the crucible is received to suppress adverse effects on the production of the fallen object. No measures have been taken against suspended solids falling into the molten metal, which is one of the interfering items.

  It is necessary to photograph the inside of the chamber with a camera or the like for the suspended matter that has fallen into the molten metal, and visually check the image. With such a monitoring method, continuous operation is difficult.

In the single crystal growth apparatus described in Patent Document 3 using radiant energy, when solidified, a temperature higher than the temperature displayed in the melt state is displayed. This is different from the emissivity at the time of solidification (εs) and the emissivity at the time of melt (εl), the emissivity is set as the emissivity at the time of melt εl (<εs), and the radiant energy is εT ⁴ ( (T: temperature)

  However, if you try to determine the suspended matter that has fallen into the molten metal, which is one of the things that interfere with the orbital immersion of the cooling body in the molten metal, after converting the temperature using radiant energy, the suspended matter will exceed the displayed temperature of the molten metal. May be displayed at a lower temperature, which is inconsistent with the prior art description that a higher temperature is displayed.

  The objective of this invention is providing the precipitation plate manufacturing apparatus and precipitation plate manufacturing method which can prevent the bad influence with respect to productivity by the thing which interferes with the immersion track | orbit in the molten metal in the molten metal.

The present invention heats the object to be melted to form a molten metal, a melting furnace for housing the molten metal, and a cooling body that is a master plate for producing a precipitation plate is transported to an upper position of the molten metal, immersed in the molten metal, And a dipping means for transporting in a direction away from the upper position of the molten metal, and a precipitation plate manufacturing apparatus for manufacturing a precipitation plate by solidifying and depositing the object to be melted on the surface of the cooling body,
Detection means for detecting radiant energy from the surface of the molten metal;
Judgment means for judging the presence or absence of an object that interferes with the immersion trajectory of the cooling body in the molten metal based on the change in the radiant energy;
Control means for controlling the operation of the immersion means according to the judgment result of the judgment means,
The determination means determines that there is an object that interferes with the immersion trajectory of the cooling body into the molten metal when the change in the radiant energy is equal to or greater than a predetermined change width and the state continues for a predetermined period. And
When it is determined that there is an object that interferes with the orbital immersion of the cooling body in the molten metal, the control means stops the immersion of the cooling body in the molten metal.

  Moreover, the present invention is characterized in that the detection means converts the radiant energy into a temperature.

In the invention, it is preferable that the detection means is a radiation thermometer.
In the invention, it is preferable that the detection means is constituted by thermography.

According to the present invention, the determination means is configured such that the increase in the radiant energy is equal to or greater than a predetermined change width, and after the state continues for a predetermined period, the change in the radiant energy is equal to or less than the predetermined change width. And, when the state continues for a predetermined period, it is judged that there is nothing that interferes with the immersion orbit in the molten metal of the cooling body,
The control means resumes the immersion of the cooling body in the molten metal when it is determined that there is no interference with the immersion path of the cooling body in the molten metal after the immersion of the cooling body in the molten metal is stopped. It is characterized by doing.

In the present invention, the determination means may be configured such that, after the decrease in the radiant energy is equal to or greater than a predetermined change width and the state continues for a predetermined period, the radiant energy is increased, and the increase in the radiant energy is When the radiant energy decreases after the predetermined change width is exceeded, the decrease in the radiant energy is equal to or less than the predetermined change width, and the state continues for a predetermined period, into the molten metal of the cooling body. Judge that there is nothing that interferes with the immersion orbit of
The control means resumes the immersion of the cooling body in the molten metal when it is determined that there is no interference with the immersion path of the cooling body in the molten metal after the immersion of the cooling body in the molten metal is stopped. It is characterized by doing.

  In the invention, it is preferable that the determination unit calculates a difference between the current radiant energy and an average value of radiant energy in a predetermined period before the present as a change in radiant energy.

In the invention, it is preferable that the determination unit converts the radiant energy into a temperature.
In addition, the present invention heats the object to be melted in a melting furnace to form a molten metal, transports a cooling body, which is an original plate for producing a precipitation plate, to a position above the molten metal accommodated in the melting furnace, immerses it in the molten metal, It is a precipitation plate manufacturing method for manufacturing a precipitation plate by solidifying and precipitating the object to be melted on the surface of the cooling body by pulling up from the inside and conveying it in a direction away from the upper position of the molten metal,
A detection process for detecting radiant energy from the surface of the molten metal;
A determination step of determining the presence or absence of an object that interferes with the immersion trajectory of the cooling body in the molten metal based on the change in the radiant energy by the determination means;
A control step of controlling the operation of the immersion means according to the judgment result of the judgment means by the control means,
In the determination step, when the change in the radiant energy is equal to or greater than a predetermined change width and the state continues for a predetermined period, it is determined that there is an object that interferes with the immersion track of the cooling body in the molten metal. And
In the control step, when it is determined that there is an object that interferes with the immersion trajectory of the cooling body in the molten metal, the precipitation plate manufacturing method is characterized in that the immersion of the cooling body in the molten metal is stopped.

  According to the present invention, when the detection means detects the radiant energy from the surface of the molten metal, the determination means determines whether there is an object that interferes with the immersion track of the cooling body in the molten metal based on the change in the radiant energy. to decide. The control means controls the operation of the dipping means according to the determination result of the determination means.

  The determination means determines that there is an object that interferes with the immersion orbit of the cooling body into the molten metal when the change in the radiant energy is equal to or greater than a predetermined change width and the state continues for a predetermined period. . When it is determined that there is an object that interferes with the orbital immersion of the cooling body in the molten metal, the control means stops the immersion of the cooling body in the molten metal.

  Thereby, generation | occurrence | production of the inferior goods by adhesion of the floating substance which is one of the things which interfere with the immersion track | orbit in the molten metal of a cooling body can be prevented, and the bad influence with respect to productivity by the floating substance in a molten metal can be prevented. Furthermore, continuous operation is also possible by the judging means and the control means.

  Further, according to the present invention, as the detection means, a temperature display familiar to human beings can be obtained by converting the radiant energy into a temperature. For example, during maintenance, the presence or absence of an object that interferes with the immersion track of the cooling body in the molten metal is confirmed. It can be detected in an easy situation.

  Further, according to the present invention, a radiation thermometer or a thermography can be used as the detection means, and the temperature can be easily detected.

  Further, according to the present invention, the determination means is configured such that the increase in the radiant energy is equal to or greater than a predetermined change width, and after the state continues for a predetermined period, the change in the radiant energy is equal to or less than the predetermined change width. When it exists and the state continues for a predetermined period, it is determined that there is no object that interferes with the immersion track of the cooling body in the molten metal.

  Further, according to the present invention, the determination means has a decrease in the radiant energy that is equal to or greater than a predetermined change width, and after the state continues for a predetermined period, the radiant energy increases, and the radiant energy increases. When the radiant energy decreases after the predetermined change width is exceeded, the decrease in the radiant energy is equal to or less than the predetermined change width, and the state continues for a predetermined period, the molten metal of the cooling body in the melt. It is judged that there is no suspended matter that is one of the things that interfere with the immersion track inside.

  When it is determined that there is nothing in the molten metal that interferes with the immersion path of the cooling body after the immersion of the cooling body in the molten metal is stopped, the control means immerses the cooling body in the molten metal. To resume.

  Thereby, since the immersion of the cooling body in the molten metal can be resumed promptly, it is possible to prevent the apparatus from being stopped for a long time, and to improve productivity due to an object that interferes with the immersion track of the cooling body in the molten metal in the molten metal. Adverse effects can be prevented.

Further, according to the present invention, the determination means calculates the difference between the current radiant energy and the average value of the radiant energy in a predetermined period before the present as the change in radiant energy.
Thereby, the change of radiant energy can be calculated easily and rapidly.

  Further, according to the present invention, as the judgment means, a temperature display familiar to human beings can be obtained by converting the radiant energy into a temperature. For example, during maintenance, the presence or absence of an object that interferes with the immersion track of the cooling body in the molten metal is confirmed. It can be detected in an easy situation.

  Further, according to the present invention, when the radiant energy is detected by the detecting means in the detecting step, the deciding step and the immersing trajectory of the cooling body in the molten metal in the molten metal based on the change of the radiant energy by the determining means. Determine if there are any interfering objects. In the control step, the operation of the immersion means is controlled by the control means according to the determination result of the determination means.

  In the determination step, when the change in radiant energy is equal to or greater than a predetermined change width and the state continues for a predetermined period, there is an object in the molten metal that interferes with the immersion track of the cooling body in the molten metal. to decide. In the control step, when it is determined that there is an object in the molten metal that interferes with the immersion track of the cooling body in the molten metal, the immersion of the cooling body in the molten metal is stopped.

  Thereby, generation | occurrence | production of the inferior goods by adhesion of the floating substance which is one of the things which interfere with the immersion track | orbit in the molten metal of a cooling body can be prevented, and the bad influence with respect to productivity by the floating substance in a molten metal can be prevented.

  FIG. 1 is a diagram showing a simplified configuration of a precipitation plate manufacturing apparatus 20 according to an embodiment of the present invention, and FIG. 2 shows an outline of precipitation plate manufacturing by the precipitation plate manufacturing apparatus 20 shown in FIG. FIG.

  The precipitation plate manufacturing apparatus 20 heats the object to be melted in a melting furnace to make a molten metal, immerses the cooling body substrate, which is the original plate for producing the precipitation plate, into the molten metal, pulls it up from the molten metal, and cools the object to be melted to the cooling body. It is used for producing a precipitation plate by solidifying and precipitating on the surface of the substrate. In the present embodiment, a case where silicon is used as the object to be dissolved and silicon is solidified and deposited on the surface of the cooling body substrate to produce layered silicon that is a deposition plate will be described.

  The deposition plate manufacturing apparatus 20 is generally provided in a chamber 21 and a processing space 22 that is an internal space formed by the chamber 21. The deposition plate manufacturing apparatus 20 heats silicon that is an object to be melted into a molten metal 23 and accommodates the molten metal 23. A melting furnace 24 and a cooling body substrate 25 which is an original plate for generating layered silicon are conveyed to a position above the molten metal 23, immersed in the molten metal 23, pulled up from the molten metal 23, and away from the upper position of the molten metal 23. A piece of layered silicon 27, which is a fallen object that falls off the cooling body substrate 25, is provided in the transportation path where the immersion apparatus 26 to be transported and the cooling body substrate 25 are transported in a direction away from the upper position of the molten metal. It includes falling object receiving means 28 for receiving, and falling object re-introducing means 29 for moving debris of the layered silicon 27 received by the falling object receiving means 28 into the melting furnace 24.

The chamber 21 has a substantially rectangular parallelepiped appearance and is a hollow structure. The chamber 21 is provided with a heat insulating and fireproof structure, although a heat insulating material such as alumina (Al ₂ O ₃ ) is lined, although not shown in a steel casing. The chamber 21 is provided with an unillustrated evacuation unit and an inert gas supply unit, and the processing space 22 inside the chamber 21 can be maintained in a vacuum atmosphere or an inert gas atmosphere.

  Also, on one side wall 21 a of the chamber 21, a cooling body is loaded to deliver the cooling body substrate 25 between a transfer device (not shown) outside the chamber 21 and an immersion device 26 in the processing space 22. A mouth 31 is formed. The cooling body carry-in port 31 is provided with an openable / closable door (not shown), and further provided with a sub chamber chamber outside the door. The sub chamber is configured so that the atmosphere can be adjusted in the same manner as the chamber 21, and a door that can be opened and closed is provided on the side opposite to the cooling body carry-in port 31. Therefore, the cooling body substrate 25 transported to the chamber 21 by the transport device is first transported into the sub chamber chamber opened to the atmosphere, and after adjusting the atmosphere in the sub chamber chamber, it is further transported by the transport means provided in the sub chamber chamber. It passes to the immersion device 26 through the cooling body inlet 31.

  On the other side wall 21b facing the one side wall 21a of the chamber 21, a cooling body is provided between another transfer device (not shown) outside the chamber 21 and an immersion device 26 in the processing space 22. A cooling body outlet 34 for delivering the substrate 25 is formed. The cooling body outlet 34 is also provided with an openable / closable door and a sub chamber chamber outside thereof, and in the same manner as in the cooling body inlet 31, between the immersion device 26 and another conveying means. The cooling body substrate 25 having the layered silicon 27 is delivered.

  The melting furnace 24 is a high-frequency induction melting furnace, in which silicon as a melting object is charged and melted, a crucible 32 in which the molten metal 23 is accommodated, a high-frequency induction coil 33 wound around the crucible 32, and a crucible 32 and a high-frequency power supply (not shown).

  The crucible 32 is a bottomed cylindrical container made of graphite, for example. The furnace body container 35 is a bottomed cylindrical container that is made of, for example, refractory bricks and is substantially similar to the crucible 32. The space between the furnace body container 35 and the crucible 32 and the high-frequency induction coil 33 is a gap in the figure, but is actually filled with a heat insulating and insulating refractory. The melting furnace 24 is installed on the bottom plate 21 c of the chamber 21 in the processing space 22. The melting furnace 24 is a device that utilizes the fact that an induction current is generated in the graphite crucible 32 and the silicon in the crucible 32 by flowing a high-frequency current from a high-frequency power source to the high-frequency induction coil 33 and generates heat by itself.

  The dipping device 26 includes a holding head 36 that holds the cooling plate substrate 25, a vertical arm 37 that is provided with the holding head 36 and extends in the vertical direction, and a vertical drive unit 38 that moves the vertical arm 37 in the vertical direction. The horizontal drive unit 39 that moves the vertical arm 37 and the holding head 36 in the horizontal direction, the cart unit 40 on which the vertical drive unit 38 and the horizontal drive unit 39 are mounted, and the cart unit 40 are guided to travel in the horizontal direction. Track member 41.

  The track member 41 is an elongated member made of, for example, metal, and is attached to the side wall adjacent to both the one side wall 21a and the other side wall 21b in the processing space 22, and the space above the crucible 32 is carried into the cooling body. It is provided so as to extend from the port 31 toward the cooling body outlet 34.

  The horizontal drive unit 39 is guided by, for example, a groove-shaped track formed on the track member 41 to move the carriage unit 40 so as to be able to advance and retract in the horizontal direction.

  The vertical drive unit 38 moves so as to approach and separate from the molten metal 23 accommodated in the crucible 32 when the vertical arm 37 and the holding head 36 attached to the vertical arm 37 are positioned in the vertical direction, that is, above the crucible 32. Can be made.

  The holding head 36 attached to the vertical arm 37 has a handling mechanism, and can hold and release the cooling substrate 25 by the operation of the handling mechanism.

  Therefore, the immersion device 26 can perform the following operations. In the immersion device 26, the vertical arm 37 and the holding head 36 move together with the carriage unit 40 to the vicinity of the cooling body inlet 31 by the operation of the horizontal driving unit 39, and receive the cooling body substrate 25 through the cooling body inlet 31. It is held by the holding head 36 and moved again from the cooling body carry-in port 31, which is the direction indicated by the arrow 42 in FIG. Further, the dipping device 26 lowers the vertical arm 37 by the operation of the vertical driving unit 38 to immerse the cooling body substrate 25 held by the holding head 36 into the molten metal 23 accommodated in the crucible 32, and silicon is cooled by the cooling body. After solidifying and precipitating on the surface of the substrate 25, the vertical arm 37 is raised again by the operation of the vertical drive unit 38 to lift the cooling body substrate 25 from the molten metal 23, and the position above the crucible 32 in the direction indicated by the arrow 43 in FIG. To the cooling body carry-out port 34, and the cooling body substrate 25 is delivered through the cooling body carry-out port 34.

  The fallen object receiving means 28 is a base plate-like member having a rectangular planar shape made of carbon or quartz. The falling object receiving means 28 may be formed such that only the part that receives the falling object is made of carbon or quartz. In this way, the portion that receives the fallen object is formed of carbon or quartz, so that it is possible to avoid contamination of impurities such as heavy metals with respect to the fallen pieces of the layered silicon 27, so that the quality of the produced precipitation plate is improved. It can be kept in dignity.

  The falling object re-introducing means 29 is a tilting means for tilting the falling object receiving means 28 so that the falling object receiving surface 28a of the falling object receiving means 28 is inclined downward as it approaches the melting furnace 24. The tilting means 29 includes, for example, a linear motion device 29a and an electric motor (not shown). In the linear motion device 29a, the pin provided at the tip of the rod is supported by the bearing 44 provided in the fallen object receiving means 28 so that the receiving surface 28a of the fallen object receiving means 28 becomes horizontal when the rod is retracted. And mounted in the chamber 21. Thus, the tilting means 29 can tilt the fallen object receiving means 28 as described above when the rod of the linear motion device 29a is extended.

  The deposition plate manufacturing apparatus 20 is further provided with a control device 45. The control device 45 is a processing circuit including, for example, a central processing unit (CPU), and is electrically connected to the power source of the melting furnace 24, each drive unit of the immersion device 26, the tilting means 29 that is a falling object re-introducing means, and the like. The overall operation of the apparatus relating to the deposition plate manufacturing is controlled according to the operation control program for the entire apparatus stored in advance in the memory unit of the control device 45.

  In the present invention, a radiation thermometer 50 is provided to detect a suspended matter that is one of the objects that interfere with the orbit of the molten metal 23 in the molten body, and the temperature of the surface of the molten metal 23 is calculated by converting the radiant energy into a temperature. Measure changes. The emissivity of the radiation thermometer is set in accordance with the emissivity of the molten metal, and even if a solid suspended matter is generated, the emissivity of the solid suspended matter is not changed. This is because even when solid suspended matter is generated, the temperature difference between the presence and absence of solid suspended matter becomes clear by setting the emissivity of the molten metal.

  The radiation thermometer 50 is provided above the crucible 32 outside the chamber 21 so that the radiation energy of the molten metal 23 can be measured. A detection window 51 is provided at a position where the imaginary line connecting the radiation thermometer 50 and the crucible 23 and the chamber 21 intersect. The detection window 51 is made of, for example, quartz, sapphire glass, or heat resistant glass.

  Since the temperature conversion of the radiant energy of silicon in a molten state and the temperature conversion of the radiant energy of solid suspended matter such as layered silicon fragments and impurities become clearly different temperatures, the temperature of the molten metal 23 is adjusted by the radiation thermometer 50. When measured, the presence or absence of suspended matter can be detected by the temperature difference.

  The measurement result of the radiation thermometer 50 due to the influence of the surface condition of the molten metal 23 is a solid floating that is one of the things that interfere with the immersion trajectory of the cooling body in the molten metal rather than the temperature of the molten silicon. There are times when the temperature of an object is measured higher and when it is measured lower. Two cases are described below.

  In this embodiment, the measurement result of the radiation thermometer 50 due to the influence of the surface state of the molten metal 23 is one of the objects that interfere with the immersion track of the cooling body in the molten metal rather than the temperature of the molten silicon. The processing for the case where the temperature of the solid suspended matter is measured as being higher will be described below.

  The control device 45 continuously measures the temperature of the molten metal 23 with the radiation thermometer 50, moves the vertical arm 37 to above the crucible 32, and lowers the cooling body substrate 25. The average temperature is compared with the current temperature of the molten metal 23. At this time, if the difference between the current temperature and the past average temperature is equal to or greater than the first threshold value, suspended matter that is one of the objects that interfere with the immersion trajectory of the cooling body in the molten metal is present in the molten metal 23. Judge.

  When it is determined that the floating substance exists in the molten metal 23, the lowering of the cooling body substrate 25 by the vertical arm 37 is stopped, and the standby state is set. The temperature measurement of the molten metal 23 by the radiation thermometer 50 is continuously performed regardless of the presence or absence of suspended matter and the operation stop of the vertical arm 37.

  When the floating material is a fragment of layered silicon, the cooling body substrate 25 resumes descending after confirming remelting. The confirmation of remelting is determined as having been remelted if the temperature of the molten metal 23 measured by the radiation thermometer 50 is equal to or lower than the second threshold value and equal to or longer than a predetermined time after detection of suspended solids.

  Since the silicon fragments remelt in the crucible 32 after a certain period of time, the temperature of the molten metal 23 after remelting becomes a constant temperature below a predetermined temperature. Therefore, a temperature in the vicinity of the molten state temperature may be set as the second threshold value.

Below, the detection of floating substances and the operation control of the immersion device 26 will be described in detail.
In the temperature measurement of the molten metal 23 by the radiation thermometer 50, the surface of the molten metal 23 is divided into a plurality of regions in advance, and the average temperature for each divided region is set as the molten metal 23 temperature in that region.

  FIG. 3 is a diagram illustrating an example of a divided region obtained by dividing the temperature measurement region. The entire area S is an opening when the crucible 32 is viewed from above, and is an area showing the entire surface of the molten metal 23. The divided areas S1 to S3 may be set in the entire area S, and the measurement values only in the divided areas may be output. The divided area does not need to cover the entire area, and may be a part of the entire area.

The reason for dividing the region in the temperature measurement is as follows.
The area occupied by the suspended matter with respect to the area of the entire surface of the molten metal 23 is very small. Therefore, when trying to detect the suspended matter using the average value of the entire surface of the molten metal 23, there is almost no difference in the value between the average value with the suspended matter and the average value without the suspended matter. There will be no.

  In order to be able to detect the effects of floating objects, it is necessary to reduce the area of the area for which the average value is calculated, and to increase the difference between the average value with and without the floating object. is important.

  In the following, processing in one divided region S1 will be described as an example, but processing similar to the following processing is performed in parallel in divided regions S2 and S3.

FIG. 4 is a diagram for explaining a process for determining the presence or absence of a suspended matter.
In the graph shown in FIG. 4, the vertical axis represents temperature (° C.), and the horizontal axis represents time (seconds). The temperature on the vertical axis is the average temperature in the divided region S1, and is simply referred to as “temperature” below.

  The temperature is continuously measured by the radiation thermometer 50, and the average temperature Ta of the period A is calculated as the molten state temperature. When Ta obtains the current measurement value, Ta is calculated using the temperature in the period A that is earlier than the current time, so Ta is calculated and updated each time a new measurement value is obtained.

  Further, ΔT (= | Tp−Ta |) and ΔT ′ (= Tp−Ta), which are differences between the current temperature Tp and the past average temperature Ta, are calculated, and ΔT is compared with the first threshold value TH1. When there is no floating substance, ΔT becomes a value substantially close to zero, and therefore ΔT does not exceed TH1.

  When suspended matter is generated in the divided region S1 due to dropping or the like, Tp rapidly increases (ΔT ′> 0). At this time, ΔT becomes large, and ΔT becomes equal to or higher than TH1 at a certain time. Further, if there is a suspended matter, the state where ΔT is equal to or higher than TH1 continues for a predetermined period B or longer.

  From these facts, based on the temperature measurement result by the radiation thermometer 50, when the period of ΔT ≧ TH1 continues for B or more, it can be determined that the suspended matter exists in the divided region S1.

  TH1 may be set as appropriate depending on the measurement conditions and the structure of the apparatus, and is, for example, 10 to 20 ° C. The period A and the period B may be set as appropriate depending on the measurement conditions, the structure of the apparatus, and the like. For example, the period A is 5 to 10 seconds, and the period B is 0.3 to 1.0 seconds.

  Regarding the operation control of the dipping device 26, it is usually determined whether the vertical arm 37 moves to the upper side of the crucible 32 and can be lowered before the cooling body substrate 25 is lowered, that is, whether there is a floating substance. to decide.

  As described above, the determination of the presence or absence of suspended matter is continuously performed, and the determination result is updated at predetermined intervals. Before lowering the cooling body substrate 25, the control device 45 refers to the determination result of the presence or absence of floating substances. If there are no floating substances, the control apparatus 45 lowers the cooling body substrate 25, and if there are floating objects, it stops the lowering and waits. State.

  After the floating substance is detected, it is also determined that the material has been melted again, and it is necessary to resume the lowering of the cooling body substrate 25.

  The temperature measurement by the radiation thermometer 50 is continued after detecting the suspended matter, and the calculation of ΔT is also continued. When the suspended matter starts to remelt, ΔT decreases again, and when the remelting ends, ΔT becomes substantially zero (ΔT is equal to or less than the second threshold value TH2). Furthermore, when all the suspended matters in the divided region S1 are remelted, the state where ΔT is equal to or lower than TH2 continues for a predetermined period C or longer.

  From these facts, based on the temperature measurement result by the radiation thermometer 50, when the period of ΔT ≦ TH2 continues for C or more, it can be determined that there is no floating substance in the divided region S1.

  The period C may be set as appropriate depending on the measurement conditions and the structure of the apparatus, and is, for example, 0.3 to 1.0 seconds.

  Regarding the operation control of the dipping device 26, after the cooling body substrate 25 stops being lowered and enters a standby state, the determination result of the presence / absence of floating substances is referred to at predetermined intervals in order to resume the lowering.

  On the other hand, as described above, the determination of the presence or absence of suspended matter is continuously performed, and the determination result to be referred to in the standby state is updated every predetermined period. When the determination result when referred to in the standby state is a result of no floating matter, the cooling body substrate 25 is resumed to be dipped and immersed.

  Since the determination of the presence or absence of suspended solids is also performed in parallel in the divided areas S2 and S3, the divided area control device 45 refers to the determination results of all the divided areas before lowering the cooling body substrate 25. If there is a suspended matter in any one of the divided areas, the descent is stopped. In the standby state, the determination result of all the divided areas is referred to, and the descent is resumed when there is no floating substance in all the divided areas.

  Next, as a measurement result of the radiation thermometer 50 due to the influence of the surface state of the molten metal 23, the solid which is one of the objects that interfere with the immersion trajectory of the cooling body in the molten metal rather than the temperature of the molten silicon. The process for the case where the temperature of the suspended matter is measured as lower is described below.

  The control device 45 continuously measures the temperature of the molten metal 23 with the radiation thermometer 50, moves the vertical arm 37 to above the crucible 32, and lowers the cooling body substrate 25. The average temperature is compared with the current temperature of the molten metal 23. At this time, if the difference between the current temperature and the past average temperature is equal to or greater than the first threshold value, it is determined that the suspended matter is present in the molten metal 23.

  When it is determined that the floating substance exists in the molten metal 23, the lowering of the cooling body substrate 25 by the vertical arm 37 is stopped, and the standby state is set. The temperature measurement of the molten metal 23 by the radiation thermometer 50 is continuously performed regardless of the presence or absence of suspended matter and the operation stop of the vertical arm 37.

  When the floating material is a fragment of layered silicon, the cooling body substrate 25 resumes descending after confirming remelting.

  Confirmation of remelting is performed after the suspended matter is detected, after the temperature of the molten metal 23 measured by the radiation thermometer 50 rises and once exceeds the third threshold, the temperature drops and then falls below the second threshold and is predetermined. If it is more than the time, it is determined that the material has been remelted.

  Since the silicon fragments remelt in the crucible 32 after a certain period of time, the temperature of the molten metal 23 after remelting becomes a constant temperature below a predetermined temperature. Therefore, a temperature in the vicinity of the molten state temperature may be set as the second threshold value.

FIG. 5 is a diagram for explaining a process for determining the presence or absence of a suspended matter.
In the graph shown in FIG. 5, the vertical axis represents temperature (° C.), and the horizontal axis represents time (seconds). The temperature on the vertical axis is the average temperature in the divided region S1, and is simply referred to as “temperature” below.

  The temperature is continuously measured by the radiation thermometer 50, and the average temperature Ta of the period A is calculated as the molten state temperature. When Ta obtains the current measurement value, Ta is calculated using the temperature in the period A that is earlier than the current time, so Ta is calculated and updated each time a new measurement value is obtained.

  Further, ΔT (= | Tp−Ta |) and ΔT ′ (= Tp−Ta), which are differences between the current temperature Tp and the past average temperature Ta, are calculated, and ΔT is compared with the first threshold value TH1. When there is no floating substance, ΔT becomes a value substantially close to zero, and therefore ΔT does not exceed TH1. Note that the threshold value TH1 in the present embodiment is the same value as the above-described threshold value TH1.

  When a suspended matter is generated in the divided region S1 due to a drop or the like, Tp rapidly decreases depending on the suspended state (ΔT ′ <0). At this time, ΔT becomes large, and ΔT becomes equal to or higher than TH1 at a certain time. Further, if there is a suspended matter, the state where ΔT is equal to or higher than TH1 continues for a predetermined period B or longer.

  From these facts, based on the temperature measurement result by the radiation thermometer 50, when the period of ΔT ≧ TH1 continues for B or more, it can be determined that the suspended matter exists in the divided region S1.

  TH1 may be set as appropriate depending on the measurement conditions and the structure of the apparatus, and is, for example, 10 to 20 ° C. The period A and the period B may be set as appropriate depending on the measurement conditions, the structure of the apparatus, and the like. For example, the period A is 5 to 10 seconds, and the period B is 0.3 to 1.0 seconds.

  Regarding the operation control of the dipping device 26, it is usually determined whether the vertical arm 37 moves to the upper side of the crucible 32 and can be lowered before the cooling body substrate 25 is lowered, that is, whether there is a floating substance. to decide.

  As described above, the determination of the presence or absence of suspended matter is continuously performed, and the determination result is updated at predetermined intervals. Before lowering the cooling body substrate 25, the control device 45 refers to the determination result of the presence or absence of floating substances. If there are no floating substances, the control apparatus 45 lowers the cooling body substrate 25, and if there are floating objects, it stops the lowering and waits. State.

  After the floating substance is detected, it is also determined that the material has been melted again, and it is necessary to resume the lowering of the cooling body substrate 25.

  The temperature measurement by the radiation thermometer 50 is continued after detecting the suspended matter, and the calculation of ΔT and ΔT ′ is also continued. When the suspended matter starts to melt again, ΔT ′ increases (ΔT ′ <0 to ΔT ′> 0 via ΔT ′ = 0), and ΔT eventually becomes equal to or greater than the third threshold value TH3. Thereafter, ΔT and ΔT ′ become smaller again, and when remelting is finished, ΔT becomes substantially zero (ΔT is equal to or less than the second threshold value TH2). Furthermore, when all the suspended matters in the divided region S1 are remelted, the state where ΔT is equal to or lower than TH2 continues for a predetermined period C or longer.

  From these facts, based on the temperature measurement result by the radiation thermometer 50, when the period of ΔT ≦ TH2 continues for C or more, it can be determined that there is no floating substance in the divided region S1.

  The period C may be set as appropriate depending on the measurement conditions and the structure of the apparatus, and is, for example, 0.3 to 1.0 seconds.

  Regarding the operation control of the dipping device 26, after the cooling body substrate 25 stops being lowered and enters a standby state, the determination result of the presence / absence of floating substances is referred to at predetermined intervals in order to resume the lowering.

  On the other hand, as described above, the determination of the presence or absence of suspended matter is continuously performed, and the determination result to be referred to in the standby state is updated every predetermined period. When the determination result when referred to in the standby state is a result of no floating matter, the cooling body substrate 25 is resumed to be dipped and immersed.

  Since the determination of the presence or absence of suspended solids is also performed in parallel in the divided areas S2 and S3, the divided area control device 45 refers to the determination results of all the divided areas before lowering the cooling body substrate 25. If there is a suspended matter in any one of the divided areas, the descent is stopped. In the standby state, the determination result of all the divided areas is referred to, and the descent is resumed when there is no floating substance in all the divided areas.

  As described above, based on the temperature measurement result by the radiation thermometer 50, it is possible to determine the presence or absence of a floating substance that is one of the objects that interfere with the orbital immersion of the cooling body in the molten metal. In this case, it is possible to stand by without immersing the cooling body substrate in the molten metal. Furthermore, it is possible to determine that the suspended matter has been remelted and to quickly resume the immersion. Therefore, it is possible to prevent generation of defective products due to adhesion of floating substances and long-time stoppage of the apparatus, and to prevent adverse effects on productivity due to floating substances in the molten metal.

  Furthermore, since the control device 45 performs the determination of the presence or absence of suspended matter that is one of the objects that interfere with the immersion trajectory of the cooling body in the molten metal and the operation control of the immersion device 26, the suspended matter is monitored and the device is stopped. There is no need for a human to perform the restart operation, and continuous operation is possible.

It is a figure which simplifies and shows the structure of the precipitation plate manufacturing apparatus 20 which is one Embodiment of this invention. It is a figure which shows the outline | summary of the precipitation plate manufacture by the precipitation plate manufacturing apparatus 20 shown in FIG. It is a figure which shows the example of the division area which divided | segmented the temperature measurement area. It is a figure for demonstrating the process which judges the presence or absence of a floating substance when temperature rises when a floating substance falls. It is a figure for demonstrating the process which judges the presence or absence of a floating body when temperature falls when a floating body falls. It is a figure which simplifies and shows the structure of the precipitation plate manufacturing apparatus 1 used for the conventional silicon manufacture. It is a figure explaining the outline | summary of the silicon manufacture in the precipitation plate manufacturing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 20 Precipitation plate manufacturing apparatus 21 Chamber 23 Molten metal 24 Melting furnace 25 Cooling body substrate 26 Immersion apparatus 27 Layered silicon 28 Falling object receiving means 29 Falling object re-introducing means 32 Crucible 33 First high frequency induction coil 45 Control apparatus 50 Radiation thermometer 51 Detection window

Claims (9)

The object to be melted is heated to form a molten metal, a melting furnace for storing the molten metal, and a cooling body that is an original plate for generating a precipitation plate are transported to a position above the molten metal, immersed in the molten metal, and pulled up from the molten metal to be melted. Dipping means for conveying in a direction away from the upper position of, and a precipitation plate production apparatus for producing a precipitation plate by solidifying and depositing the object to be melted on the surface of the cooling body,
Detection means for detecting radiant energy from the surface of the molten metal;
Judgment means for judging the presence or absence of an object that interferes with the immersion trajectory of the cooling body in the molten metal based on the change in the radiant energy;
Control means for controlling the operation of the immersion means according to the judgment result of the judgment means,
The determination means determines that there is an object that interferes with the immersion trajectory of the cooling body into the molten metal when the change in the radiant energy is equal to or greater than a predetermined change width and the state continues for a predetermined period. And
The said control means stops the immersion in the molten metal of a cooling body, when it is judged that there exists an object which interferes with the immersion track | orbit in the molten metal of a cooling body, The precipitation plate manufacturing apparatus characterized by the above-mentioned.   The deposition plate manufacturing apparatus according to claim 1, wherein the detection unit converts the radiant energy into a temperature.   The deposition plate manufacturing apparatus according to claim 1, wherein the detection unit includes a radiation thermometer.   The deposition plate manufacturing apparatus according to claim 1, wherein the detection unit is configured by thermography. The determination means is configured such that after the increase in the radiant energy is equal to or greater than a predetermined change width and the state continues for a predetermined period, the change in the radiant energy is equal to or less than a predetermined change width and the state is When continuing for a predetermined period, it is judged that there is no object that interferes with the immersion orbit of the cooling body in the molten metal,
The control means resumes the immersion of the cooling body in the molten metal when it is determined that there is no interference with the immersion path of the cooling body in the molten metal after the immersion of the cooling body in the molten metal is stopped. The deposition plate manufacturing apparatus according to any one of claims 1 to 4, wherein The determination means is that the decrease in the radiant energy is greater than or equal to a predetermined change width, and after the state continues for a predetermined period, the radiant energy increases, and the increase in the radiant energy is greater than or equal to a predetermined change width. After that, when the radiant energy decreases, the decrease in the radiant energy is equal to or less than a predetermined change width, and the state continues for a predetermined period, it interferes with the immersion trajectory in the molten metal of the cooling body. Judge that there is nothing to do,
The control means resumes the immersion of the cooling body in the molten metal when it is determined that there is no interference with the immersion path of the cooling body in the molten metal after the immersion of the cooling body in the molten metal is stopped. The precipitation plate manufacturing apparatus according to any one of claims 1 to 5, wherein   The said determination means calculates the difference of the present radiant energy and the average value of the radiant energy of the past predetermined period from the present as a change of radiant energy, The any one of Claims 1-6 characterized by the above-mentioned. The deposition plate manufacturing apparatus described in 1.   The precipitation plate manufacturing apparatus according to claim 1, wherein the determination unit converts the radiant energy into a temperature. The object to be melted is heated in a melting furnace to form a molten metal, and a cooling body, which is an original sheet for producing a precipitation plate, is transported to a position above the molten metal accommodated in the melting furnace, immersed in the molten metal, and pulled up from the molten metal to be melted. A precipitation plate manufacturing method for manufacturing a precipitation plate by solidifying and precipitating the object to be melted on the surface of the cooling body by conveying in a direction away from the upper position of
A detection process for detecting radiant energy from the surface of the molten metal;
A determination step of determining the presence or absence of an object that interferes with the immersion trajectory of the cooling body in the molten metal based on the change in the radiant energy by the determination means;
A control step of controlling the operation of the immersion means according to the judgment result of the judgment means by the control means,
In the determination step, when the change in the radiant energy is equal to or greater than a predetermined change width and the state continues for a predetermined period, it is determined that there is an object that interferes with the immersion track of the cooling body in the molten metal. And
In the control step, when it is determined that there is an object that interferes with the orbit of immersion of the cooling body into the molten metal, the immersion plate manufacturing method is characterized by stopping the immersion of the cooling body into the molten metal.

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