JP2020063163A - Apparatus for manufacturing single crystal - Google Patents

Abstract

To provide an apparatus for manufacturing a single crystal, capable of preventing a part of the raw material of a granular raw material melting vessel from contaminating a single crystal product to manufacture a high quality single crystal.SOLUTION: In the apparatus for manufacturing a single crystal, capable of supplying a granular raw material to granular raw material melting means, melting the supplied granular raw material using the granular raw material melting means, supplying the obtained raw material melt into a melt formed on the upper surface of a lower seed single crystal to form a mixed melt, depositing a solid as a single crystal from the mixed melt to manufacture a large-sized single crystal, the granular raw material melting means comprises at least: a granular raw material melting vessel made of the same material as the single crystal and having an approximately recessed shape; and an infrared irradiation device provided above the granular raw material melting vessel and irradiating the granular raw material supplied in the granular raw material melting vessel with infrared to melt the granular raw material and form the raw material melt.SELECTED DRAWING: Figure 2

Description

  TECHNICAL FIELD The present invention relates to a single crystal production apparatus for producing a large single crystal of high quality with high efficiency while homogenizing the composition to an optimum composition.

  A single crystal refers to a material in which the atoms that form the substance are arranged properly over the entire area in a defined manner. Such a single crystal is used in various fields such as a semiconductor material and an optical material, because the original characteristics of the substance are notably disturbed and the atomic arrangement is not disturbed.

When using a single crystal material for industrial purposes, not only excellent characteristics but also low manufacturing and processing costs of the single crystal are important factors. Single crystals such as silicon (Si) which is the main semiconductor material, lutetium silicate (LSO; Lu ₂ SiO ₅ ) which is a phosphor material, and yttrium aluminum garnet (YAG; Y ₃ Al ₅ O ₁₂ ) which is a laser material are , Are all products manufactured by the "pull-up method".

  As the above-mentioned single crystal materials such as Si, LSO, and YAG, materials in which useful additives are added to required concentrations are used. For example, Si is used as an N-type semiconductor with phosphorus added or as a P-type semiconductor with boron added. Cerium is added to LSO, and neodymium is added to YAG.

  When manufacturing the material containing these additives by the above-mentioned pulling method, the raw material is melted in a suitable crucible, and the seed single crystal is dipped in the obtained melt to thicken it while upward. It is pulled up to produce a single crystal.

  This method is a method of solidifying the entire melt from the top to the bottom, which is a method belonging to the so-called unidirectional solidification method, so by the segregation phenomenon that occurs when producing a single crystal as a solid from the melt, in the obtained single crystal However, there is a drawback in that the additive concentration of is not constant.

  That is, the additive concentration in the melt and the additive concentration in the solidified single crystal are not the same, and solidification proceeds at a ratio defined by the substance. This ratio is called the “partition coefficient”, and when the additive concentration in the melt is 1, the additive concentration in the single crystal produced is, for example, about 0.35 when phosphorus is added to silicon and Ce when added to LSO. When added, it is said to be about 0.2.

  Therefore, when solidification is started from the melt containing the additive, the concentration of the additive in the generated single crystal becomes lower than that in the melt at first, and the difference remains in the melt. Therefore, as the growth proceeds, the concentration of the additive in the melt gradually increases. The ratio of the additive concentration in the melt to the additive concentration in the resulting single crystal is defined by the "partition coefficient," so if crystallization progresses and the additive concentration in the melt increases, the The additive concentration in the crystal also gradually increases.

  A floating zone melting method is known as another method for producing a single crystal material. This floating zone melting method is generally a method of melting the lower end of a raw material rod formed into a round bar shape and the upper surface of a seed single crystal arranged on the lower side of this raw material rod, and joining both melts together. While maintaining the melt with surface tension between the upper raw material rod and the lower seed single crystal, the raw material is melted on the upper side of the melt, and the single crystal as a solid is precipitated from the melt on the lower side of the melt. This is a method for producing a single crystal ingot.

  As a raw material melting means, a high-frequency floating zone melting method utilizing high-frequency induction (high-frequency FZ method) and an infrared floating zone melting method forming a melt by irradiating infrared rays (infrared FZ method) are known.

  In the high frequency FZ method and the infrared FZ method, the supply of the raw material into the melt and the precipitation of the single crystal from the melt are continued. Therefore, the additive concentration in the obtained single crystal and the additive concentration in the raw material are the same in a steady state, and a single crystal product having a uniform composition can be obtained. Further, since no crucible is used, it is possible to manufacture a high-purity single crystal that does not contain a crucible component, and is suitable for melting a raw material for which no suitable crucible material is found.

  However, the high-frequency FZ method requires a dense and high-quality raw material rod to continue stable high-frequency induction, and is difficult to apply to an insulating material.

  Further, the infrared FZ method is widely applicable from an insulating material to a good conductor material, and although it is known that the raw material rod does not necessarily need to be highly dense, the diameter of the rod-shaped single crystal that can be manufactured is 20 to It is as small as 30 mm, and it is used only for research and development.

  In the infrared FZ method, conventionally, infrared rays were radiated onto the sample from the horizontal direction. A large-diameter single crystal cannot be produced by this horizontal irradiation infrared FZ method (hereinafter, also referred to as a horizontal FZ method) because the melt having a large diameter necessary for producing a large-diameter single crystal is used. It is difficult to form.

  That is, being able to irradiate the raw material with infrared rays to form a melt means that the infrared rays are absorbed by the raw material and become heat. Since infrared rays are absorbed by the melt while passing through the melt, the amount of infrared rays that can reach the deep part of the melt gradually decreases.

  Therefore, the temperature of the melt decreases as the distance from the surface of the melt increases, and the interface shape between the single crystal and the melt grown and the raw material rod and the melt tend to be convex with respect to the melt. is there.

  Therefore, in the vicinity of the central portion of the melt, the distance between the upper material rod and the lower crystal rod is narrower than that in the outer peripheral portion of the melt. When the raw material rod and the crystal rod come into contact with each other, the shape of the melt is disturbed, and the melt further falls to make it impossible to continue the production of the single crystal. Therefore, it is desirable to keep the distance between the raw material rod and the crystal rod as wide as possible.

  In order to avoid contact between the upper raw material rod and the lower crystal rod, when trying to increase the infrared ray amount in the center portion of the single crystal to be grown, the melt amount in the outer portion increases and the melt easily drops. Will end up. Therefore, it was extremely difficult to manufacture a single crystal having a large diameter exceeding 30 mm by the horizontal FZ method.

  Therefore, a tilt irradiation type infrared FZ method (hereinafter also referred to as a tilt FZ method) of irradiating infrared rays from obliquely above to below has been developed by the present inventor. In the tilted FZ method, the melt formed by melting the raw material naturally flows downward due to gravity and moves, and gets on the seed single crystal arranged in the lower part.

  If the upper surface of the seed single crystal is flat or concave, the melt on the upper surface of the seed single crystal is maintained by surface tension. Therefore, in principle, the gradient FZ method can stably hold the melt on the seed single crystal even if the diameter of the seed single crystal is large, and the diameter of the single crystal that can be grown is not limited.

  Therefore, if it is possible to simultaneously realize the melting of the raw material and the stable solidification of the formed melt as a single crystal below, a single crystal having a large diameter can be produced (Patent Document 1).

  Up to now, the production of a silicon single crystal has been attempted by the tilted FZ method, and a single crystal having a large diameter of about 150 mm has already been produced. The silicon single crystal that can be manufactured by the conventional horizontal FZ method has a diameter of about 30 mm, which is a remarkable advance.

  The tilted FZ method is a method of irradiating a raw material with infrared rays to melt and solidify the raw material to produce a single crystal. The “method of forming the granular raw material into a rod shape and using it” was general, but the inclined FZ method is a method in which the granular raw material may be melted as it is and solidified as a single crystal.

  This is a method of forming a melt on the upper surface of a seed single crystal, dropping a raw material melt obtained by melting a granular raw material into the melt, and solidifying the single crystal from the mixed melt formed. Means that it has become possible.

  Therefore, the present inventor melts the granular raw material as it is by using a granular raw material melting means, instead of the conventional method of “forming the granular raw material into a rod shape and using it”, and the obtained raw material melt is used as a seed seed. A single crystal production apparatus and a single crystal production method have been found in which a single crystal is solidified from a mixed melt produced by supplying it into a melt formed on the upper surface of the crystal (Patent Documents 2 and 3).

  As a result, the energy required for melting the raw material can be significantly reduced compared to the conventional method using a large raw material rod, and the granular raw material is stored in the hopper for storing the granular raw material during the growing process. Since it has become possible to replenish it, it has become possible to very easily manufacture a long single crystal having a large diameter.

Japanese Patent No. 5279727 International application number PCT / JP2018 / 013162 International application number PCT / JP2018 / 013163

  In the single crystal manufacturing apparatus and the single crystal manufacturing method described in Patent Documents 2 and 3, as the material of the granular raw material melting container for melting the granular raw material, a material capable of stably holding the molten raw material melt is selected. There is a need to.

  However, in reality, the granular raw material melting container and the raw material melt react with each other, and in some cases, this reaction cannot be ignored.

  For example, when quartz is used as a granular raw material melting container for melting and holding a granular raw material of silicon, silicon monoxide (SiO) is generated by the reaction between silicon and quartz, and the generated silicon monoxide (SiO) There was a drawback that some of them were mixed in the single crystal product.

  In order to avoid this, if silicon carbide is used as a material for the granular raw material melting container instead of quartz, it is difficult to manufacture a large-sized and high-quality silicon carbide granular raw material melting container, and in addition, There is a problem that silicon carbide is mixed in the silicon single crystal product.

  In addition, when manufacturing a lithium tantalate single crystal, it is common to use iridium metal as the material of the granular raw material melting vessel, but iridium metal produces iridium oxide in an oxidizing atmosphere, and this There was a drawback that it was mixed in the single crystal product.

  Also in the case of producing a gallium oxide single crystal, the use of a granular raw material melting vessel made of iridium metal has a drawback that iridium oxide is mixed in the single crystal product. If an attempt is made to maintain a reducing atmosphere in order to avoid this, a phenomenon will occur in which gallium oxide vaporizes violently.

  The present invention has been made in view of such circumstances, and it is possible to prevent a part of the raw material of the granular raw material melting container from being mixed in the single crystal product, and to manufacture a high quality single crystal. An object is to provide a single crystal manufacturing apparatus.

The present invention has been invented to solve the above-mentioned problems in the prior art,
The single crystal production apparatus of the present invention,
The granular raw material is supplied to the granular raw material melting means, and the supplied granular raw material is melted by the granular raw material melting means, and the raw material melt obtained is in the melt formed on the upper surface of the seed single crystal below. A single crystal production apparatus for producing a large single crystal by supplying a mixed melt and precipitating a solid from the mixed melt as a single crystal,
The granular raw material melting means,
A substantially concave granular raw material melting container made of the same material as the single crystal,
An infrared irradiation device which is provided above the granular raw material melting container and radiates infrared rays to the granular raw material supplied in the granular raw material melting container to melt the raw material melt,
At least.

  A granular raw material melting vessel made of the same material as the single crystal to be produced is used, and the granular raw material supplied into the granular raw material melting vessel is directly irradiated with infrared rays to melt the granular raw material, thereby making it possible to have impurities. It is possible to obtain a raw material melt. Therefore, by using this raw material melt, it is possible to manufacture a high-quality single crystal in which no impurities are mixed.

  Further, with such a granular raw material melting means, even if a part of the raw material of the granular raw material melting container is mixed in the raw material melt when melting the granular raw material, the mixed raw material is a single crystal grown. Since it is the same material as, no inconvenience occurs.

Further, the single crystal production apparatus of the present invention,
A plurality of the granular raw material melting means are provided.

  When the granular raw material in the granular raw material melting container is irradiated with infrared rays to be melted and the resulting raw material melt is supplied onto the seed single crystal below, the granular raw material is continuously supplied into the granular raw material melting container. However, it is necessary to continuously supply the formed raw material melt downward.

  If the raw material melt cannot be continuously supplied downward, the production of the single crystal is interrupted, causing striae and other factors that deteriorate the performance of the single crystal product.

  While supplying the granular raw material into the granular raw material melting container, the granular raw material in the granular raw material melting container is irradiated with infrared rays to be melted, and the resulting raw material melt is continuously fed downward. The unmelted granular raw material remaining therein may be supplied downward together with the raw material melt.

  Therefore, a plurality of granular raw material melting means are provided, for example, while the raw material melt is being supplied downward in the first granular raw material melting container, the granular raw material is supplied in the second granular raw material melting container to emit infrared rays. After irradiating to form a raw material melt and melting the granular raw material, as soon as the supply of the raw material melt from the first granular raw material melting container is completed, the raw material melt from the second granular raw material melting container It is preferable to start the supply of the liquid so that the supply of the raw material melt to the lower side is performed without interruption.

  If the continuous supply of the raw material melt cannot be completed in time between the two granular raw material melting containers, a third granular raw material melting container is arranged so that the raw material melt can be supplied at a predetermined supply speed without interruption. However, the number is not particularly limited.

Further, the single crystal production apparatus of the present invention,
A container holder is provided outside the granular raw material melting container.

  If a granular raw material melting container is manufactured and used with the same material as the single crystal product, it may be difficult to continue stable use depending on the material because the granular raw material melting container may crack or chip during use. is there.

  To prevent this, a container holder is provided on the outside of the granular raw material melting container so that even if the granular raw material melting container is cracked or chipped, the single crystal production will not be affected. can do.

Further, the single crystal production apparatus of the present invention,
A heating device is provided outside the container holder.

  By providing the heating device on the outside of the container holder, the amount of infrared rays for melting the granular raw material in the granular raw material melting container can be reduced, and efficient operation becomes possible. Furthermore, when the method of inclining the granular raw material melting container and supplying the raw material melt downward is adopted, it is possible to prevent the melt temperature from dropping sharply even if the irradiation of infrared rays is temporarily stopped. The melt can be stably supplied downward.

Further, the single crystal production apparatus of the present invention,
The granular raw material melting means,
It is characterized by having a weight measuring device having a function of constantly measuring the weight of the granular raw material melting container and adjusting the feed rate of the raw material melt fed downward.

  The total weight of the granular raw material melting container is constantly measured by a weight measuring device. Thereby, the raw material melt to be formed can be supplied downward at a predetermined supply rate.

Further, the single crystal production apparatus of the present invention,
The infrared irradiation device,
It is characterized in that a slider for slidingly moving the position of the infrared irradiation device is provided.

Furthermore, the single crystal production apparatus of the present invention,
The granular raw material melting means,
It is characterized by having an inclining means for changing the granular raw material melting container to a predetermined angle.

  The granular raw material stored in the granular raw material melting container is irradiated with infrared rays from above to be melted to obtain a raw material melt. When the granular raw material melting container is tilted, the raw material melt is dropped downward, but in order to prevent the melt temperature from lowering and solidifying at this time, the raw material melt always receives a necessary amount of infrared rays. Irradiation is desirable.

  When the granular raw material melting container is tilted, the center position of the raw material melt fluctuates, so a mechanism is added to match the fluctuating center position of the raw material melt with the center position of the irradiated infrared light, which is always necessary for the raw material melt. If the amount of infrared rays is irradiated, the temperature of the raw material melt can be prevented from lowering and solidifying.

  Therefore, the installation position of the infrared irradiation device may be arbitrarily moved by the slider, and the angle of the granular raw material melting container may be changed by the tilting means.

Further, the single crystal production apparatus of the present invention,
The tilting means,
A wire supporting one end of the granular raw material melting container from above,
Winding the wire to tilt the granular raw material melting container, or unwinding the wire to return the tilted granular raw material melting container to a horizontal position;
It is characterized by having.

  The inclining means is not particularly limited, but it is preferable that the angle of the granular raw material melting container can be changed by winding or unwinding a wire supported at one end of the granular raw material melting container. With such an inclining means, since the structure is simple, maintenance is easy, and the inclining means can be made compact.

Further, the single crystal production apparatus of the present invention,
The winding and unwinding device,
It is characterized in that a slider for slidingly moving the arrangement position of the winding / unwinding device is provided.

Furthermore, the single crystal production apparatus of the present invention,
In the granular raw material melting container,
It is characterized in that a slider for slidingly moving the arrangement position of the granular raw material melting container is provided.

  If a slider is provided on the winding / unwinding device or the granular raw material melting container in this way, even if the central position of the raw material melt changes when the granular raw material melting container is tilted, the center of the changing raw material melt The position and the central position of the infrared ray to be irradiated can be matched with each other by the winding / unwinding device or the sliding movement of the granular raw material melting container. Therefore, it is possible to prevent the temperature of the raw material melt from dropping and solidifying when it falls.

  The winding and unwinding device and the slider of the granular raw material melting container are preferably used together with the slider of the infrared irradiation device and the tilting means of the granular raw material melting container described above.

  According to the single crystal production apparatus of the present invention, a granular raw material melting vessel made of the same material as the single crystal to be produced is used, and the granular raw material is supplied and melted in the granular raw material melting vessel to obtain the obtained raw material melt. By supplying to the upper surface of the seed single crystal at a predetermined supply rate, it is possible to produce a large single crystal homogenized with an optimal concentration composition in both the vertical and horizontal directions.

FIG. 1 is a schematic view of an embodiment of the single crystal production apparatus of the present invention. FIG. 2 is an explanatory diagram for explaining the operation of the granular raw material melting container in the single crystal manufacturing apparatus shown in FIG. FIG. 3 is an explanatory diagram for explaining another granular raw material melting container. FIG. 4 is a schematic diagram for explaining an embodiment in which a plurality of granular raw material melting means are provided. FIG. 5 is a schematic view of another embodiment of the single crystal production apparatus of the present invention.

  Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings.

  The single crystal production apparatus of the present invention is for producing a large single crystal having a diameter exceeding 100 to 300 mm with high efficiency while homogenizing it to an optimum composition. To produce such a large single crystal, a melt method of melting a raw material and solidifying the obtained melt to produce a single crystal is the mainstream, and the present invention also relates to this melt method. It is a thing.

  The basic configuration of the single crystal production apparatus of the present invention and the basic steps of the single crystal production method have already been described in detail in Patent Documents 1 to 3 by the present inventor. Only the basic description is given, and the details are omitted.

In the present specification, the "seed single crystal" refers to the initial form of the crystal when producing a large-diameter single crystal using a single crystal producing apparatus. A single crystal that is grown from this seed single crystal and maintains the same orientation as a whole is called a "single crystal". On the other hand, although individual crystals are single crystals, aggregates of individual crystals having different orientations are called "polycrystals".
Further, in the present specification, the "granular raw material" is a raw material which is a source of a single crystal to be produced, and is powdered (grained). The "granular raw material" includes a granular crystal base material and a granular additive.

<Single crystal manufacturing apparatus 10a>
As shown in FIG. 1, the single crystal production apparatus 10a of the present invention is equipped with a single crystal production chamber 11 capable of evacuating the inside and maintaining an inert gas atmosphere such as argon gas. Below the chamber 11, a single crystal holding table 18, a holding table rotating mechanism 20, and an elevating means 22 are installed, and on the single crystal holding table 18, a seed single crystal 12 having a substantially circular cross section is arranged. It is like this.

  An auxiliary heating device 86 for heating the seed single crystal 12 placed on the single crystal holding table 18 is provided outside the single crystal holding table 18, and a heat insulating material 87 is placed outside the auxiliary heating device 86. ing. The single crystal manufacturing chamber 11 has a water-cooled structure and can efficiently adjust the atmosphere inside.

  On the other hand, above the inside of the single crystal manufacturing chamber 11, a hopper 33 that accommodates the granular raw material 52 is arranged. A known attachment / detachment mechanism 46 is provided on the upper end of the hopper 33 so that an accommodation container 47 accommodating the granular raw material 52 can be detachably attached.

  The attachment / detachment mechanism 46 has an atmosphere adjustment function of arbitrarily adjusting the atmosphere in the attachment / detachment mechanism 46 and the accommodation container 47. In FIG. 1, the storage container 47 is in a state of being removed from the hopper 33.

  By using the accommodating container 47 that can be attached to and detached from the hopper 33, the granular raw material 52 can be added to the hopper as needed at any time even while the single crystal production apparatus 10a is being activated to produce a single crystal. Can be replenished within 33. Therefore, it is not necessary to use the large hopper 33, and the single crystal manufacturing apparatus 10a can be downsized.

  Here, the granular raw material 52 accommodated in the hopper 33 is, for example, a granular mixture in which the additive-free granular silicon and the granular raw material in which the additive is added at a high concentration are mixed in the optimum composition. Although the hopper 33 is used alone in the present embodiment, the hopper for containing the additive-free granular silicon and the hopper for containing the granular raw material to which the additive is added at a high concentration may be separately provided. It is a thing.

  The opening at the bottom of the hopper 33 is directly connected to the single crystal production chamber 11 so that the inside of the hopper 33 and the inside of the single crystal production chamber 11 are always in the same atmosphere by an atmosphere adjusting device (not shown). It is configured.

  Further, a granular material scraping device (hereinafter, also simply referred to as a scraping device) 48 is provided on the side of the opening of the hopper 33. In the scraping device 48, a container having a spoon-like shape coated with propylene is attached to the tip of the rod, the rod is inserted into the opening of the hopper 33, and the granular raw material 52 is pulled out while being placed on the container. By rotating the lever half way, the granular raw material 52 in the container can be supplied onto the granular raw material quantitative supply device (hereinafter, also simply referred to as fixed amount supply device) 50 located at the lower part of the hopper 33.

  The constant quantity supply device 50 adjusts a predetermined supply amount while measuring the weight of the granular raw material 52, and supplies the predetermined supply amount to the supply pipe 51 with a supply position adjusting function below. In the figure, reference numeral 60 is a position adjusting mechanism.

  The granular raw material 52 supplied to the supply pipe 51 passes through the inside of the supply pipe 51, and the granular raw material melting container (hereinafter also referred to as a melting container) 56 of the granular raw material melting means 80 arranged below the supply pipe 51. Is supplied to a predetermined position.

  The granular raw material 52 supplied to the melting vessel 56 is melted by the infrared rays 74 directly radiated by the infrared radiating device 72 to be a raw material melt 67. In addition, it is preferable that the infrared irradiation device 72 is provided with a slider 75 that slides the arrangement position in the left-right direction. Thereby, the infrared rays 74 can be irradiated to a desired position of the melting container 56.

  A laser light irradiation device is preferably used as the infrared irradiation device 72, but in addition to the laser light irradiation device, the infrared light emitted from the infrared lamp is configured to be reflected by the inner surface of the ellipsoidal reflecting mirror. It may be an irradiation device. In this case, a halogen lamp or a xenon lamp can be used as the infrared lamp.

  The raw material melt 67 obtained by the granular raw material melting means 80 is dropped onto the seed single crystal 12 located below the melting vessel 56. The upper surface of the seed single crystal 12 is melted by the infrared rays 28 irradiated from the infrared irradiation device 26 to be an optimum melt 91, and the raw material melt 67 obtained by the granular raw material melting means 80 is dropped there.

  At this time, the single crystal holding table 18 holding the seed single crystal 12 is rotated at a predetermined speed by the holding table rotating mechanism 20 to reduce the uneven irradiation of the infrared rays 28 irradiated on the upper surface of the seed single crystal 12 to form The temperature of the melt phase to be applied can be homogenized. The infrared irradiator 26 may be the same as the infrared irradiator 72.

  Further, the elevating means 22 provided on the single crystal holding table 18 is operated to control the position in the height direction of the melt phase formed on the upper surface of the seed single crystal 12 to the optimum position.

  An infrared transmission window 27 is provided between the seed single crystal 12 and the infrared irradiation device 26 that heats the seed single crystal 12, and an infrared transmission window is provided between the melting container 56 and the infrared irradiation device 72. 73 is installed. The material of the infrared transmission windows 27 and 73 is not particularly limited as long as it is a material that can transmit the infrared rays 28 and 74, but is preferably made of quartz, for example.

As a result, the single crystal 92 is gradually grown while the raw material melt 67 is dropped into the optimum melt 91 on the seed single crystal 12, and finally a large single crystal 92 can be obtained.
The single crystal production apparatus 10a according to one embodiment of the present invention is configured as described above, and in particular, the granular raw material melting means 80 has a characteristic configuration, and therefore its details will be described below.

<Granular raw material melting means 80>
As shown in FIGS. 1 and 2, in the single crystal production apparatus 10a of the present invention, the granular raw material melting means 80 uses the granular raw material melting vessel 56 made of the same material as the single crystal 92 to be produced.

  The melting container 56 measures the weight of the melting container 56 so that it can be seen how much the granular raw material 52 has been supplied, and a weight measuring device 70 having a function of adjusting the supply rate of the raw material melt 67 supplied downward is provided. It is preferably provided.

  The granular raw material 52 supplied into the melting container 56 made of the same material as the manufactured single crystal 92 is melted by being directly irradiated with the infrared rays 74 by the infrared irradiation device 72 to obtain the raw material melt 67. You can

  The production of the melting vessel 56 is not particularly limited, but when producing a silicon single crystal, for example, it is preferable to produce as follows.

  That is, first, a container manufacturing block (not shown) made of high-purity silicon is prepared. The high-purity silicon that is the material of the container manufacturing block may be either single crystal or polycrystal, but is preferably single crystal.

  Infrared rays are irradiated near the center of the container manufacturing block to melt it, and the raw material melt formed by tilting the container manufacturing block is dropped downward to empty it. This operation is repeated a plurality of times to form a depression having a predetermined size, and the melting container 56 is obtained.

  As shown in FIG. 2A, a container holder 55 is provided outside the melting container 56 so as to surround the melting container 56, which causes the melting container 56 to crack or chip. Also, the raw material melt 67 in the melting container 56 can be retained in the melting container 56.

  The granular raw material 52 is supplied into the melting container 56, and when a predetermined amount is confirmed by the weight measuring device 70, as shown in FIG. 2B, the infrared irradiation device 72 directly irradiates the infrared light 74 to melt it. A raw material melt 67 free of impurities can be obtained.

  Here, the light amount of the infrared rays 74 required to melt the predetermined amount of the granular raw material 52 is known by a preliminary test performed in advance, and the granular raw material 52 is melted by continuing the irradiation of the infrared rays 74 for a certain time, A raw material melt 67 free from impurities can be obtained.

  Then, as shown in FIG. 2C, the obtained raw material melt 67 containing no impurities is wound by the winding / unwinding device 69 to wind up the wire 68 supporting one end of the melting vessel 56 to melt the vessel 56. Is inclined and dropped from the melting vessel 56 onto the seed single crystal 12 below. In order to prevent the temperature of the raw material melt 67 from dropping and solidifying during dropping, it is desirable that the raw material melt 67 is always irradiated with a necessary amount of infrared rays 74.

  Here, the inclination angle of the melting container 56 is controlled by constantly measuring the weight of the raw material melt 67 with the weight measuring device 70 in order to always drop a predetermined amount of the raw material melt 67 at a predetermined position. preferable.

  When the melting vessel 56 is tilted, the center position of the raw material melt 67 fluctuates. Therefore, a mechanism is added to match the fluctuating center position of the raw material melt 67 with the center position of the irradiated infrared rays 74. By constantly irradiating the necessary amount of infrared rays 74 to the above, it is possible to prevent the temperature of the raw material melt 67 from decreasing and solidifying.

  As a mechanism for matching the two, the infrared irradiation device 72 is moved, the melting container 56 and the winding / rewinding device 69 are moved, or the infrared irradiation device 72, the melting container 56, and the winding / rewinding device 69 are all moved. It is preferable to always irradiate the optimum position of the raw material melt 67 with the infrared rays 74 depending on whether or not to do so.

  The movement of the infrared irradiation device 72, the melting container 56, and the winding / rewinding device 69 is not particularly limited as long as it is a known mechanism, but it is preferable to perform it through, for example, the sliders 75, 76, 77.

  After the raw material melt 67 has been dropped, the winding and unwinding device 69 unwinds the wire 68 that supports one end of the melting container 56, and the melting container 56 is again placed in a horizontal state as shown in FIG. Return to.

  As shown in FIG. 3, the granular raw material melting means 80 may be provided with a heating device 58 outside the container holder 55 that holds the melting container 56.

  When the heating device 58 is provided, the melting container 56 and the container holder 55 are heated by the heating device 58 to a temperature higher than the melting temperature of the granular raw material 52 by 100 before supplying the granular raw material 52 into the melting container 56. It is preferable to heat to a temperature as low as about ℃. As a result, the light amount of the infrared rays 74 for melting the granular raw material 52 in the melting container 56 can be reduced, and efficient operation becomes possible.

  Further, when the method of inclining the melting vessel 56 and supplying the raw material melt 67 downward is adopted, even if the irradiation of the infrared rays 74 is temporarily stopped, the temperature of the raw material melt 67 is rapidly lowered. Therefore, the raw material melt 67 can be stably supplied downward.

  When the raw material melt 57 is obtained by using the granular raw material melting means 80 of the present invention and the raw material melt 67 containing no impurities is supplied into the optimum melt 91 on the seed single crystal 12, It is desirable that the feeding be continuously performed in order to manufacture a high quality single crystal 92.

  Therefore, as shown in FIG. 4, a plurality of the granular raw material melting means 80 described above are prepared, and the granular raw material melting means 80 are circumferentially arranged on the seed single crystal 12 at equal intervals. It is preferable that the raw material melt 57 is dropped onto the surface 12 and supplied continuously.

  Although the preferred embodiment of the single crystal production apparatus 10a of the present invention has been described above, the present invention is not limited to the above embodiment, and for example, as the tilting means for tilting the melting container 56, the wire 68 described above is used. Other than the one using the winding and unwinding device 69, the structure may be such as a seesaw capable of rotating the melting container 56, and is not particularly limited.

  Further, in the present embodiment, the structure other than the above-mentioned granular raw material melting means 80 is basically the same structure as the single crystal manufacturing apparatus disclosed in Patent Document 2, but as shown in FIG. The granular raw material melting means 80 described above can also be applied to the single crystal manufacturing apparatus 10b disclosed in Patent Document 3 using the crucible 61.

  The details of the single crystal manufacturing apparatus 10b using the crucible 61 are disclosed in Patent Document 3, and therefore the description of the details is omitted in this specification, but the raw material melt obtained in the melting container 56 described above is omitted. The liquid 67 is dropped on the seed single crystal 12 in the crucible 61. In FIG. 5, reference numerals that are the same as those in FIG. 1 have the same configuration. Reference numeral 61 is a crucible, 62 is an auxiliary heating device, 63 is a crucible holder, 64 is a crucible stand, 30 is an infrared irradiation device, 31 is an infrared transmitting window, and 32 is infrared.

  As described above, the single crystal manufacturing apparatuses 10a and 10b of the present invention can be variously modified without departing from the purpose thereof.

10a Single crystal manufacturing apparatus 10b Single crystal manufacturing apparatus 11 Single crystal manufacturing chamber 12 Seed single crystal 18 Single crystal holding table 20 Holding table rotating mechanism 22 Elevating means 26 Infrared irradiation device 27 Infrared transmission window 28 Infrared 30 Infrared irradiation device 31 Infrared transmission window 32 infrared ray 33 hopper 46 attaching / detaching mechanism 47 accommodating container 48 scraping device 50 quantitative supply device 51 supply pipe 52 granular raw material 55 container holder 56 granular raw material melting container 57 raw material melt 58 heating device 60 position adjusting mechanism 61 crucible 62 auxiliary heating device 63 Crucible holder 64 Crucible stand 67 Raw material melt 68 Wire 69 Winding and unwinding device 70 Weight measuring device 72 Infrared irradiation device 73 Infrared transmission window 74 Infrared 75 Slider 76 Slider 77 Slider 80 Granular raw material melting means 86 Auxiliary heating device 87 Heat insulating material 91 Optimal melt 92 single Crystal

Claims (10)

The granular raw material is supplied to the granular raw material melting means, and the supplied granular raw material is melted by the granular raw material melting means, and the raw material melt obtained is in the melt formed on the upper surface of the seed single crystal below. A single crystal production apparatus for producing a large single crystal by supplying a mixed melt and precipitating a solid from the mixed melt as a single crystal,
The granular raw material melting means,
A substantially concave granular raw material melting container made of the same material as the single crystal,
An infrared irradiation device which is provided above the granular raw material melting container and radiates infrared rays to the granular raw material supplied in the granular raw material melting container to melt the raw material melt,
An apparatus for producing a single crystal, comprising at least:   The single crystal manufacturing apparatus according to claim 1, wherein a plurality of the granular raw material melting means are provided.   The single crystal production apparatus according to claim 1, wherein a container holder is provided outside the granular raw material melting container.   The single crystal production apparatus according to claim 3, wherein a heating device is provided outside the container holder. The granular raw material melting means,
5. A weight measuring device having a function of constantly measuring the weight of the granular raw material melting container and adjusting the supply rate of the raw material melt supplied downward. Single crystal manufacturing equipment. The infrared irradiation device,
The single crystal manufacturing apparatus according to claim 1, further comprising a slider that slides a position where the infrared irradiation device is disposed. The granular raw material melting means,
7. The single crystal manufacturing apparatus according to claim 1, further comprising an inclining means for changing the granular raw material melting container to a predetermined angle. The tilting means,
A wire supporting one end of the granular raw material melting container from above,
Winding the wire to tilt the granular raw material melting container, or unwinding the wire to return the tilted granular raw material melting container to a horizontal position, a winding and unwinding device,
The single crystal manufacturing apparatus according to claim 7, further comprising: The winding and unwinding device,
9. The single crystal manufacturing apparatus according to claim 8, further comprising a slider that slides the position at which the winding and unwinding device is disposed. In the granular raw material melting container,
The single crystal manufacturing apparatus according to claim 1, further comprising a slider that slides a position where the granular raw material melting container is disposed.

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