Device for producing single-crystal sheet, and single-crystal sheet

Abstract

[Problem] To provide: a device for continuously producing a single-crystal sheet of high quality; and a single-crystal sheet produced with this device. [Solution] This device for continuously producing a single-crystal sheet is provided with: laser beam emitters which emit laser beams to the upper surface of a raw-material bulk held by a holding part and form a melt zone; and a lift which immerses a thin-shaped seed single crystal in the melt zone and pulling it upward. By immersing the seed single crystal in the melt zone and pulling it upward, a single-crystal sheet is continuously produced. The device for producing a single-crystal sheet is further provided with a horizontal-movement device for moving the holding part in a horizontal direction which is the same as a thickness direction of the seed single crystal. The laser beam emitters emit linear laser beams, and the optical axes of the linear laser beams are within planes orthogonal to the horizontal direction which is the moving direction of the holding part moved by the horizontal-movement device, or within planes slightly slanting off from the plane orthogonal to the horizontal direction toward the seed single crystal side.

Description

Thin plate single crystal manufacturing apparatus and thin plate single crystal

[0001] The present invention relates to a thin plate single crystal manufacturing apparatus for manufacturing thin plate single crystals using raw material blocks made of various materials such as metals, semiconductors, and insulators, and to a thin plate single crystal manufactured by this thin plate single crystal manufacturing apparatus.

[0002] Typical single crystal materials currently in demand in the semiconductor IC and other device markets include silicon and ferroelectric materials such as lithium niobate and lithium tantalate. Most of these single crystal materials are provided to the device manufacturing industry in the form of wafers (thin single crystal plates). Most wafers are produced by using a method known as the pulling method, in which large, round rod-shaped single crystals measuring several hundred millimeters in diameter and several meters in length are produced in a crucible. These wafers are then cut into thin plates approximately several hundred micrometers thick and polished.

[0003] Most of the single crystal materials currently available on the market are produced by the pulling method, but this method has the following inherent drawbacks.

[0004] The first drawback is the need to use a crucible to hold the raw material melt, which increases the cost of single crystal production if the crucible material is expensive. Also, the crucible material may be mixed into the single crystal product as an impurity or may form a solid solution, degrading the performance of the single crystal product.

[0005] The second drawback is that the pulling method is a unidirectional solidification method, and the concentration of useful additives in the resulting single crystal ingot is not uniform. To overcome this drawback, the double crucible method was developed, but there are no known examples of this method being successfully commercialized.

[0006] The main manufacturing method for semiconductor silicon single crystals, a typical single-crystal material, is the pulling method using a quartz crucible. Essentially, crucible materials are required to be non-reactive with the raw material melt and to be usable up to temperatures approximately 100°C higher than the melting point of the raw material. However, quartz materials react with the silicon raw material melt to form silicon monoxide. Furthermore, quartz materials tend to soften at temperatures higher than approximately 1,000°C, and quartz crucibles are already softened to the point where they cannot stand on their own at temperatures near the melting point of silicon, 1,414°C. Therefore, it is extremely difficult to use them at temperatures approximately 100°C higher than the melting point.

[0007] As such, it is extremely inappropriate to use a quartz crucible as a crucible for producing silicon single crystals, and its use should be avoided in principle, but the reality is that quartz crucibles are used out of necessity because no other alternative materials have been found. As a result, the single crystal products contain various problems, as described below.

[0008] To produce single crystals using the pulling method, the raw material must be completely melted and then solidified. High-purity silicon raw material is produced using the Siemens process, and the raw material produced using this process contains a large amount of acicular single crystals. Acicular single crystals have high crystalline perfection, and it is known that melting them requires higher temperatures and longer times than melting ordinary powdered raw materials.

[0009] Although it is possible to melt needle-shaped silicon single crystals by maintaining the quartz crucible at a temperature close to the melting point of silicon for a long period of time, the quartz crucible generates silicon monoxide through a chemical reaction with the silicon melt. Although the reaction of the generated silicon monoxide stops when the amount reaches a level determined by the solubility, the silicon monoxide evaporates from the surface of the silicon melt, and the silicon monoxide generation reaction continues to compensate for the amount lost through the evaporation of silicon monoxide. The area of ​​the quartz crucible in contact with the liquid surface gradually wears away and becomes thinner, resulting in the development of holes.

[0010] For the above reasons, the pulling operation must be started even when a large amount of acicular single crystal remains in the raw material melt. In the case of silicon, the volume of the solid is larger than that of the melt, and the specific gravity of the solid is smaller than that of the melt, so the acicular single crystal gradually moves above the melt due to buoyancy.

[0011] These remaining needle-like single crystals are likely to adhere to the surface of the single crystal at the solid-liquid interface at the bottom of the single crystal being manufactured. At the site where the needle-like single crystals have adhered, there is little chance that the orientation of the single crystal being manufactured and the orientation of the attached needle-like single crystals will exactly match, resulting in a mismatch, and the growth of negative crystals formed at the facets will begin.

[0012] When the size of the negative crystals reaches a certain size, they continue to grow in the closing direction, and eventually become voids formed entirely by facets, remaining in the single crystal. The number of needle-shaped single crystals remaining in the melt gradually decreases, and as melting progresses, the size of the needle-shaped single crystals also decreases, and soon all the needle-shaped single crystals remaining in the raw material melt disappear, and the formation of negative crystals also stops.

[0013] The reason why a large number of voids are found in the initial growth portion of silicon single crystals produced by the pulling method, but gradually disappear, is due to the above reasons. The commonly held theory that "the voids observed in silicon single crystals are lattice vacancies that have moved through the single crystal due to temperature differences and accumulated in one place" is impossible to explain the mechanism by which tens of millions of vacancies accumulate in one place, and must be said to be an absurd and outrageous argument.

[0014] The problem with quartz crucibles, which will be discussed next, is that quartz reacts with molten silicon to produce silicon monoxide, and some of the silicon monoxide produced ends up being mixed into the silicon single crystal being produced as a solid solution.

[0015] This is the biggest problem with silicon single crystals produced by the current pulling method.

[0016] Quartz is silicon dioxide, and its chemical formula is SiO2. This SiO2 chemically reacts with molten silicon to produce silicon monoxide (SiO) as shown in the following formula 1:

[0017]

[0018] The silicon monoxide produced is mixed into the silicon melt and forms a solid solution in the solidified single crystal. Therefore, strictly speaking, silicon single crystals produced by the pulling method should be called "silicon-silicon monoxide solid solution," and it should be noted that calling them high-purity silicon single crystals does not reflect the actual situation.

[0019] As described above, the single crystal product produced by melting high-purity silicon raw material in a quartz crucible and using the pulling method should more accurately be called a "silicon silicon monoxide solid solution," but in the following explanation it will be referred to as a "silicon single crystal."

[0020] The amount of silicon monoxide mixed into the silicon single crystal to form a solid solution gradually decreases as the temperature drops below about 1,000°C. As this amount of silicon monoxide decreases, the excess silicon monoxide precipitates in the solid. In other words, a large amount of silicon monoxide, which is a heterogeneous component, precipitates in the silicon single crystal solid formed by strong covalent bonds.

[0021] This phenomenon is common in naturally occurring minerals and is named "exsolution." Typical minerals that exhibit exsolution include luminous minerals such as star ruby, star sapphire, and cat's eye. The precipitated components generally precipitate along the plane with the widest interplanar spacing of the parent single crystal. In the case of silicon single crystals, they also precipitate along the (111) plane with the widest interplanar spacing.

[0022] If this exsolution of silicon monoxide occurs, the physical properties of the single crystal, such as its resistance, will fluctuate significantly. Furthermore, a large number of fine cracks will form around the exsolution site. When wet oxidation is performed, the silicon adjacent to the fine cracks will react with the oxidizing solution and be converted to oxide. The oxide is dissolved and removed by treatment with hydrofluoric acid, resulting in the formation of numerous grooves along the (111) plane after treatment with hydrofluoric acid.

[0023] This is the cause of a defect structure that appears in silicon-silicon monoxide solid solution single crystals called "oxidized induced stacking faults (OSFs)." To prevent this from occurring, the amount of silicon monoxide in solid solution must be kept below a trace amount that does not cause exsolution.

[0024] However, it is practically impossible to suppress the silicon monoxide content in silicon single crystals produced by the pulling method using a quartz crucible to such a small amount, and if one wishes to produce truly high-purity, high-quality silicon single crystals, there is no other way than to adopt a method other than the pulling method.

[0025] Furthermore, semiconductor silicon single crystals are used as P-type or N-type semiconductors by adding boron or phosphorus, but the amount of boron or phosphorus added in the single crystal ingot produced by the pulling method is not uniform, and the boron or phosphorus added is thin in the initial growth portion and gradually becomes denser as the growth proceeds. In particular, since the distribution coefficient of phosphorus in N-type silicon doped with phosphorus is small, about 0.35, when the growth has progressed to about half of the raw material melt, the phosphorus concentration in the product often becomes too dense and cannot meet specifications.

[0026] For this reason, efforts are being made to halt growth, remove the product, and then replenish the remaining raw material melt with the amount of raw material that was consumed before restarting growth of a second crystal.However, even with this, the optimal concentration portion in the product is limited, and the current situation is that the yield of single crystal products with the optimal composition that the device industry desires is low.

[0027] Silicon single crystals produced by the pulling method are generally considered to be dislocation-free single crystals with the highest purity and perfection ever produced by humankind. However, in reality, the concentration of additives is not uniform, and they contain exsolution structures that are much larger than minute defects such as dislocations and have a significant impact on physical properties.

[0028] Furthermore, when cutting a large round bar-shaped single crystal into thin plates, a large amount of cutting loss occurs, which results in multiple problems, such as wasting the expensive single crystal produced.

[0029] The cost of generating electricity from solar cells, which aim to make effective use of solar energy, remains higher than any other power generation method, including nuclear, hydroelectric, and thermal power generation. To reduce power generation costs, it is necessary to reduce the manufacturing costs of high-quality wafers, which are the main components, and to improve the solar conversion efficiency.

[0030] Instead of cutting and processing large single crystals produced by the pulling method to produce wafers, new manufacturing equipment and methods have been explored that can produce homogeneous thin single crystals with optimal additive concentrations from the start, thereby dramatically reducing the cost of wafer production.

[0031] A method called the Edge-defined Film-fed Growth (EFG) method has been developed as a method for producing thin-plate single crystal silicon, and a large amount of public funds have been invested in this method, mainly in the United States, with the aim of putting it into practical use.

[0032] However, in the case of silicon, a material that can withstand long-term stable use as the material for the raw material melt supply jig called a die, which is a main component of the EFG method, has not been found, and practical application has not been achieved. The only known practical examples of the EFG method are gallium oxide plates and sapphire plates that use iridium or molybdenum as dies.

[0033] In light of this situation, the present inventor has recently developed a new manufacturing device for producing large, thin plate-shaped single crystals. This device is capable of irradiating the upper surface of a raw material lump with a line-shaped laser beam and producing large, high-purity, thin plate-shaped single crystals from the melt obtained on the upper surface of the raw material lump. This device is of great significance.

[0034] This thin-plate single crystal manufacturing apparatus makes it possible to manufacture large, high-quality thin-plate single crystals with a width of 300 mm or more that are homogeneous in dopant concentration and free of impurities, which was previously impossible to produce using conventional pulling methods or radio-frequency floating zone methods. This allows for a dramatic reduction in the manufacturing costs of high-quality, large-diameter wafers (Patent Document 1).

[0035] Japanese Patent Application Laid-Open No. 2023-025811

[0036] This thin plate single crystal manufacturing apparatus continuously produces thin plate single crystals by irradiating the upper surface of a raw material lump with a line-shaped laser beam to form a molten region on the upper surface of the raw material lump, and then immersing a thin plate-shaped seed single crystal in this region and pulling it up. This thin plate single crystal manufacturing apparatus does not require the use of a crucible to hold the raw material melt, and can produce thin plate single crystals with a homogeneous concentration of additives. It is an innovative apparatus that can produce thin plate single crystals with high purity, high quality, and low cost.

[0037] However, it has been found that depending on the single crystal material, it may be difficult to manufacture a thin plate-shaped single crystal.

[0038] First, in the thin plate single crystal manufacturing equipment, a shielding plate is used to prevent the reflected laser light from hitting the thin plate single crystal during manufacturing and heating the thin plate single crystal.However, if the single crystal material is a highly thermally conductive material such as a metal material, a melting zone of a size taking into account the placement of the shielding plate can be formed on the upper surface of the raw material block without any problems.

[0039] However, in the case of materials with low thermal conductivity, such as oxides, although a melted region can be formed in the area irradiated with laser light, the melted region does not spread to areas other than the irradiated area that are not irradiated with laser light, and it is difficult to ensure a melted region of a size that takes into account the placement of the shielding plate, which can make it difficult to produce thin plate-shaped single crystals.

[0040] That is, as shown in Fig. 8(a), laser beams 112a and 112b are irradiated from an oblique direction onto upper surface 102 of raw material lump 100 via two laser beam irradiators (not shown), thereby forming melted regions 120a and 120b. When raw material lump 100 is made of a material with high thermal conductivity, such as a metal material, melted regions 120a and 120b formed at the irradiated portions of raw material lump 100 with laser beams 112a and 112b expand as the intensity of laser beams 112a and 112b increases, due to a rise in the surrounding temperature caused by thermal conduction, as shown in Fig. 8(b).

[0041] When the two melted regions 120a and 120b each expand further, the two melted regions 120a and 120b merge into one large melted region 120. This allows the melted region 120 to be large enough to easily accommodate the placement of the shielding plates 140a and 140b, as shown in Figure 8(c).

[0042] In addition to the irradiation with the laser beams 112a and 112b, spot-shaped laser beams 116a and 116b are irradiated onto both ends of the upper surface 102 of the melted region 120 on one side and the other side in the width direction of the insertion portion of the seed single crystal 134 to pull the seed single crystal 134 upward, thereby regulating the expansion of the width of the thin plate-shaped single crystal 130, thereby enabling stable production of the thin plate-shaped single crystal 130 from the center portion of the melted region 120 via the joint portion 132. In the figure, reference numeral 110a denotes the exit port of the laser beam 112a, reference numeral 110b denotes the exit port of the laser beam 112b, reference numeral 114a denotes the exit port of the spot-shaped laser beam 116a, and reference numeral 114b denotes the exit port of the spot-shaped laser beam 116b.

[0043] On the other hand, as shown in FIG. 9( a), in the case of a material with low thermal conductivity such as an oxide, even if the irradiation intensity of the laser beams 112 a and 112 b is increased, the spread of the two melted regions 120 a and 120 b is small, and it is difficult to form melted regions large enough to enable the installation of the shielding plates 140 a and 140 b.

[0044] Therefore, if the left and right distance is narrowed in the region of the upper surface 102 of the raw material lump 100 where the laser beams 112a, 112b are incident, as shown in Figure 9(b), the left and right molten regions 120a, 120b can expand and connect to form a single molten region 120. However, even if a single connected molten region 120 is forcibly formed in this manner, the formed molten region 120 is small, and it is therefore difficult to insert shielding plates 140a, 140b and a seed single crystal 134 to produce a stable thin plate-shaped single crystal 130, as shown in Figure 9(c).

[0045] In addition, in Figure 9(a), if the irradiation intensity of the laser beams 112a and 112b is further increased to form melted regions 120a and 120b of the required size, evaporation becomes more intense from the areas of the upper surface 102 of the raw material lump 100 where the laser beams 112a and 112b are irradiated, and even with this method, it may be difficult to stably produce a thin plate-shaped single crystal 130.

[0046] Therefore, the present invention aims to provide a thin plate single crystal manufacturing apparatus that can continuously produce high-quality, large thin plate single crystals even from materials with low thermal conductivity such as oxides, and thin plate single crystals manufactured using this thin plate single crystal manufacturing apparatus.

[0047] The present invention has been invented to solve the problems of the prior art described above, and provides a thin plate single crystal manufacturing apparatus comprising at least: a holding section for holding a raw material lump; a laser light irradiator for irradiating a laser light onto an upper side of the raw material lump held by the holding section, thereby melting the surface of the upper side and forming a melted region; and a lifting device for immersing a thin plate-shaped seed single crystal in the melted region formed on the upper side of the raw material lump and lifting the seed single crystal upward from the immersed state, wherein the seed single crystal is immersed in the melting region via the lifting device, thereby starting single crystal growth from the lower side of the immersed seed single crystal, and the seed single crystal is further lifted upward via the lifting device, thereby continuously manufacturing thin plate-shaped single crystals, and the thin plate-shaped single crystal manufacturing apparatus comprises: a horizontal movement device for moving the holding section for holding the raw material lump in the same horizontal direction as the thickness direction of the seed single crystal according to the manufacturing status of the thin plate-shaped single crystal; and the laser light irradiator is configured such that the laser light irradiated from the laser light irradiator is a line-shaped laser light, The optical axis of the linear laser light is configured to be included within a plane perpendicular to the horizontal direction, which is the direction of movement of the holding part moved by the horizontal movement device, or the optical axis of the linear laser light is configured to be included within a plane that is slightly inclined toward the seed single crystal with respect to the plane perpendicular to the horizontal direction, which is the direction of movement of the holding part moved by the horizontal movement device.

[0048] With this configuration, the light reflected from the surface of the melt formed by irradiating the raw material lump with the line-shaped laser light will not be irradiated onto the thin plate-shaped single crystal being produced.

[0049] In addition, when attempting to produce a large, thin plate-shaped single crystal, it is necessary to form a large molten region, and the output of the laser light irradiation device (for example, a laser oscillation device) used is also required to be increased.

[0050] If it is difficult to manufacture such a high-power laser light irradiation device, multiple low-power linear laser beams can be irradiated from both sides of the width of the raw material block (the thin plate-shaped single crystal being manufactured) at the same position (irradiation area) on the upper surface of the raw material block, thereby forming a large melting area equivalent to that achieved when a high-power laser light irradiation device is used.

[0051] When forming a large melted region by irradiating a low-power linear laser beam from both sides in the width direction of the raw material ingot (the thin plate-shaped single crystal to be produced) in this manner, it is necessary to arrange the laser beam so that the reflected light from the melt surface of the linear laser beam irradiated from one side does not hit the linear laser beam exit port arranged on the other side.

[0052] The reason is that if the reflected light irradiates the other side of the linear laser light output port, it may cause fluctuations in the output value or may even be destroyed.

[0053] To avoid such a situation, the optical axis of the line-shaped laser light is included within a plane that is slightly inclined toward the seed single crystal (thin plate-shaped single crystal), so that the reflected light from the melt surface of the line-shaped laser light irradiated from the exit port located on one side can pass through while avoiding the line-shaped laser light exit port located on the other side.

[0054] In this case, the inclination angle of the linear laser light can be adjusted to match the size and position of the exit port for the linear laser light located on the other side, and is not particularly limited; the inclination angle is a maximum of 10 degrees, preferably a maximum of 7 degrees, and more preferably a maximum of 5 degrees.Within this inclination angle, the reflected light can pass through, avoiding the exit port for the linear laser light located on the other side.

[0055] The inclination angle can be increased by moving the position (irradiation area) where the line-shaped laser light is irradiated away from the position of the seed single crystal (thin plate-shaped single crystal); however, if the position (irradiation area) where the line-shaped laser light is irradiated away from the position of the seed single crystal (thin plate-shaped single crystal), the temperature of the melt in the melting area decreases as it moves away from the irradiation area, and therefore the temperature of the melt at the insertion position of the seed single crystal will decrease.

[0056] Therefore, in order to stably produce a thin plate-shaped single crystal with a large tilt angle, it is necessary to increase the temperature of the irradiation area, which may cause inconvenience such as intensified evaporation from the melt. Therefore, in reality, it is desirable to limit the tilt angle to a maximum of about 5 degrees.

[0057] Furthermore, with this configuration, even if the raw material block is made of a material with low thermal conductivity, such as an oxide, by moving the raw material block in the depth direction, the molten region formed by the irradiation of the line-shaped laser light can be expanded in the direction of movement (depth direction) of the raw material block, thereby forming a molten region of the desired size on the upper side surface of the raw material block, and enabling the continuous production of high-quality, large-sized thin plate-shaped single crystals.

[0058] The thin plate single crystal manufacturing apparatus of the present invention forms a molten zone by irradiating a linear laser beam onto the upper surface of a raw material lump of high purity and homogeneous additive concentration, and since the size of the molten zone formed is constant, the so-called solvent migration method is automatically applied while the raw material lump continues to melt and solidify into a single crystal. Therefore, the concentration of additives in the single crystal product becomes homogeneous regardless of the magnitude of the partition coefficient of the additive.

[0059] Furthermore, in the thin plate single crystal manufacturing apparatus of the present invention, the optical axis of the line-shaped laser beam is contained within a plane perpendicular to the horizontal direction, which is the direction of movement of the holder, or is contained within a plane slightly inclined toward the seed single crystal with respect to the plane perpendicular to the horizontal direction, which is the direction of movement of the holder, so that when the line-shaped laser beam is irradiated onto the upper surface of the raw material lump to form a melted zone, the light of the line-shaped laser beam irradiated onto the upper surface of the raw material lump, reflected from the melt surface of the melted zone formed on the upper surface of the raw material lump, does not strike the thin plate single crystal being manufactured. Therefore, there is no need to install a shielding plate as in the conventional method, and thin plate single crystals can be reliably and continuously manufactured without unnecessarily widening the melted zone.

[0060] The invention of this thin plate single crystal manufacturing apparatus means that the long-desired low-cost production of high-quality, large, thin plate single crystals with high purity and homogeneous composition has been realized, and its contribution to related industries will be immeasurable.

[0061] Furthermore, the thin plate single crystal manufacturing apparatus of the present invention is characterized in that the laser light irradiation device comprises a main line-shaped laser light irradiation device used to form a melted region on the upper side surface of the raw material lump, and a sub-line-shaped laser light irradiation device used to form a soaking region within the formed melted region.

[0062] In this way, if the raw material block is configured so that, in addition to the main linear laser light emitted from the main linear laser light irradiating device, the secondary linear laser light emitted from the secondary linear laser light irradiating device is irradiated onto the upper surface of the raw material block, a soaking area can be formed by irradiating the secondary linear laser light within the melting area formed by irradiating the main linear laser light.

[0063] If a seed single crystal is immersed in this soaking zone to produce a thin plate-shaped single crystal, it is possible to continuously produce thin plate-shaped single crystals with a good yield.

[0064] The thin plate single crystal manufacturing apparatus of the present invention is characterized in that the raw material block is a rectangular parallelepiped or a cube.

[0065] In this way, the upper surface of a rectangular or cubic raw material block is irradiated with a main linear laser beam so that the optical axis of the main linear laser beam is included in a plane perpendicular to the horizontal direction (depth direction), which is basically the direction in which the raw material block moves.Once a melted area has been formed on the upper surface of the raw material block, the raw material block can be moved horizontally (depth direction) to expand the melted area and form a melted area of ​​the desired size.

[0066] In this case, by ensuring that the optical axis of the main linear laser light is contained within a plane perpendicular to the horizontal direction (depth direction), which is the direction of movement of the raw material block held in the holding section, the optical axis of the reflected light from the surface of the raw material melt formed will also be contained within a plane perpendicular to the horizontal direction (depth direction), which is the direction of movement of the raw material block held in the holding section, just like the irradiated main linear laser light.

[0067] This eliminates the phenomenon of reflected light being irradiated onto the seed single crystal used or the thin plate-shaped single crystal being produced, thereby eliminating the need for a shielding plate, which was previously essential, and simplifying the production equipment and process.

[0068] Furthermore, the thin plate single crystal manufacturing apparatus of the present invention is characterized in that, when the raw material block is held in the holding section, the main line-shaped laser light is irradiated onto the upper side of the raw material block from diagonally above the raw material block.

[0069] In this way, the main line-shaped laser light irradiating device that irradiates the main line-shaped laser light does not get in the way of the thin plate-shaped single crystal being produced, so that thin plate-shaped single crystal can be produced continuously.

[0070] Furthermore, since the light reflected from the surface of the melt within the melting region of the main linear laser light travels in the same plane as the irradiated light, the reflected light does not hit the seed single crystal or the thin plate-shaped single crystal to be produced, and thin plate-shaped single crystals can be produced with a high yield.

[0071] Furthermore, when producing a large thin plate single crystal, a high-power laser beam irradiation device (e.g., a laser oscillator) is required, but in reality, it may be difficult to use such a high-power laser beam irradiation device. Therefore, when a large thin plate single crystal is produced by using multiple low- or medium-power laser beam irradiation devices to ensure the required irradiation amount, if the output ports of multiple line-shaped laser beams are arranged biased to one side in the width direction of the thin plate single crystal, the space may become cramped.

[0072] In such a case, it is sufficient to arrange the line-shaped laser beam exit ports on both sides of the thin plate-like single crystal in the width direction. When the line-shaped laser beam exit ports are arranged on both sides of the thin plate-like single crystal in the width direction, it is sufficient to arrange the optical axis of the line-shaped laser beam within a plane slightly inclined toward the seed single crystal (thin plate-like single crystal) so as to prevent the reflected light of the line-shaped laser beam irradiated from one side and reflected by the melt surface of the melted region formed on the upper surface of the raw material lump from directly hitting another line-shaped laser beam exit port arranged on the other side. This allows for stable production of large thin plate-like single crystals.

[0073] Furthermore, the thin plate single crystal manufacturing apparatus of the present invention is characterized in that, when the raw material block is held in the holding section, the horizontal movement device is configured to reverse the movement direction of the raw material block when the melting area reaches one end of the depth direction of the upper surface of the raw material block due to the movement of the holding section, and to reverse the movement direction of the raw material block when the melting area reaches the other end of the depth direction of the upper surface of the raw material block, and to repeat this operation.

[0074] With the raw material block held in the holder in this manner, when the melting zone reaches one end of the depth direction of the upper surface of the raw material block due to the movement of the holder, the horizontal movement device reverses the direction of movement of the raw material block while continuing to produce the thin plate-shaped single crystal without interruption, and when the melting zone reaches the other end of the depth direction of the upper surface of the raw material block, the horizontal movement device reverses the direction of movement of the raw material block while continuing to produce the thin plate-shaped single crystal without interruption.By repeating this operation, it is possible to continuously produce long thin plate-shaped single crystals using large raw material blocks with large depths and heights.The width of the raw material block is specified to match the width of the thin plate-shaped single crystal to be produced.

[0075] The thin plate single crystal manufacturing apparatus of the present invention is characterized in that a preheating device for preheating the raw material ingot is disposed around the holding section.

[0076] By providing such a preheating device, the raw material lump can be preheated to near its melting point, thereby significantly reducing the irradiation dose of the main linear laser beam and reducing the temperature fluctuation range of the raw material lump when the raw material lump is irradiated with the main linear laser beam to form a melted region, thereby preventing undesirable phenomena such as cracking of the raw material lump that have conventionally occurred due to sudden temperature fluctuations.

[0077] The thin plate single crystal manufacturing apparatus of the present invention is characterized by comprising a vertical movement device for moving the holding part in the vertical direction.

[0078] By providing such an up-and-down moving device, the vertical position of the melting area on the upper surface of the raw material block can be kept constant at all times, thereby making it possible to efficiently continuously produce high-quality, large, ultra-long, thin plate-shaped single crystals without changing the irradiation angle of the main line-shaped laser light irradiated from the main line-shaped laser light irradiation device.

[0079] The thin plate single crystal manufacturing apparatus of the present invention is characterized in that the lifting device is a winding and storing device that continuously winds up the manufactured thin plate single crystal in a roll and stores it.

[0080] Such a winding and storage device can reliably wind up continuously produced thin plate single crystals without increasing the size of the thin plate single crystal production apparatus more than necessary. Furthermore, if the produced thin plate single crystals are in the form of a roll, they can be easily transported during shipping, improving handleability.

[0081] The thin plate single crystal manufacturing apparatus of the present invention is characterized in that the lifting device is a cutting and storing device that pulls up the manufactured thin plate single crystal, cuts it into pieces of a predetermined length, and stores them.

[0082] With this cutting and storing device, even if the thickness of the thin plate single crystal is large and it cannot be wound up, it is possible to continuously produce long thin plate single crystals at low cost by cutting and storing the crystals, for example, every 2 m. Note that the method for cutting the thin plate single crystal can be selected arbitrarily, such as a method of irradiating a line-shaped laser beam via a cutting laser beam irradiation device or a method using a heat ray.

[0083] Furthermore, the thin plate single crystal manufacturing apparatus of the present invention is characterized in that, when the raw material block is held in the holding section, the main line-shaped laser light irradiated from the main line-shaped laser light irradiating device is a first main line-shaped laser light irradiated from one end side of the portion on the upper side of the raw material block where the seed single crystal is inserted, and a second main line-shaped laser light irradiated from the other end side of the portion on the upper side of the raw material block where the seed single crystal is inserted.

[0084] In this way, if the first main linear laser beam and the second main linear laser beam are irradiated at positions on both sides of the thickness direction of the seed single crystal, centered on the insertion position of the seed single crystal inserted into the melting zone formed on the upper surface of the raw material lump, at a distance optimally matched to the composition of the raw material lump, it is possible to form melting zones on one side and the other side of the thickness direction of the seed single crystal relative to the upper surface of the raw material lump while moving the raw material lump to one side and the other in the depth direction.

[0085] This makes it possible to continuously produce thin plate-shaped single crystals using large raw material blocks while reversing the direction of movement of the raw material blocks, thereby enabling the continuous production of high-quality, large thin plate-shaped single crystals.

[0086] Furthermore, the thin plate single crystal manufacturing apparatus of the present invention is characterized in that, when the raw material block is held in the holding section, the secondary line-shaped laser light is irradiated onto the upper side of the raw material block from diagonally above the raw material block.

[0087] In this way, if the secondary line-shaped laser light irradiated from the secondary line-shaped laser light irradiating device is configured to irradiate the upper side of the raw material block from diagonally above the raw material block in addition to the main line-shaped laser light, a soaking area can be formed by irradiating the secondary line-shaped laser light within the melting area formed by irradiating the main line-shaped laser light.

[0088] If a seed single crystal is immersed in this soaking zone to produce a thin plate-shaped single crystal, it is possible to continuously produce thin plate-shaped single crystals with a good yield.

[0089] Furthermore, the thin plate single crystal manufacturing apparatus of the present invention is characterized in that, when the raw material block is held in the holding section, the sub-line-shaped laser light is a first sub-line-shaped laser light irradiated from one end side of the portion on the upper surface of the raw material block where the seed single crystal is inserted, and a second sub-line-shaped laser light irradiated from the other end side of the portion on the upper surface of the raw material block where the seed single crystal is inserted.

[0090] In this way, by irradiating the upper surface of the raw material lump with the first main linear laser light and irradiating the second sub-linear laser light on the opposite side of the irradiation position of the first main linear laser light near the insertion position of the seed single crystal to be inserted into the melting zone to be formed, a soaking zone can be formed near the location where the seed single crystal is inserted in the melting zone.

[0091] A seed single crystal is inserted into the formed soaking zone, and a thin plate-shaped single crystal is grown while being pulled upward, thereby enabling stable production of high-quality thin plate-shaped single crystals.

[0092] Similarly, if the second main linear laser beam is irradiated onto the upper surface of the raw material block, and the first sub-linear laser beam is irradiated onto the opposite side of the irradiation position of the second main linear laser beam near the insertion position of the seed single crystal to be inserted into the melting zone to be formed, a soaking zone can be formed near the location where the seed single crystal is inserted in the melting zone.

[0093] As a result, when moving a raw material block, for example, from one end side to the other end side in the depth direction, a first main linear laser beam is irradiated near one end side of the portion where the seed single crystal is inserted to form a melting zone, and a second sub-linear laser beam is irradiated near the other end side of the portion where the seed single crystal is inserted to form a soaking zone, and the seed thin plate-shaped single crystal is inserted into this soaking zone, allowing for stable production of thin plate-shaped single crystals.

[0094] If the raw material block continues to be moved from one end to the other end in the depth direction, the melted region will reach one end of the raw material block, at which point the irradiation of the first main linear laser beam is stopped, and the direction of movement of the raw material block is reversed while irradiating it with the second main linear laser beam, and the raw material block is moved from the other end to the one end in the depth direction.

[0095] At this time, the irradiation of the second sub-line laser beam is stopped, and the first sub-line laser beam is irradiated to form a soaking zone in the melting zone, and the thin plate single crystal is continuously produced. As the raw material block continues to move, the melting zone again reaches the other end of the raw material block. While performing this operation, the direction of movement of the raw material block is repeatedly reversed. This makes it possible to use a large raw material block that is large in both the depth and height directions, and to produce an ultra-long, high-quality thin plate single crystal.

[0096] In addition, the thin plate single crystal manufacturing apparatus of the present invention is characterized in that it is equipped with a spot laser light irradiation device that, when the raw material block is held in the holding section, irradiates spot laser light onto one end side and the other end side in the width direction of the portion on the upper side of the raw material block where the seed single crystal is inserted.

[0097] This allows spot-shaped laser light to be irradiated onto the upper surface of the raw material block from one end side and the other end side in the width direction of the thin plate-shaped single crystal being pulled, maintaining the temperature of the irradiated area higher than the surrounding area, thereby regulating the expansion of the width of the thin plate-shaped single crystal and regulating the width size of the thin plate-shaped single crystal to a predetermined size.

[0098] Furthermore, the thin plate single crystal manufacturing apparatus of the present invention is characterized in that the spot laser light irradiating device that irradiates the spot laser light comprises: a first spot laser light irradiating device that irradiates a first spot laser light onto one end side in the width direction of the portion on the upper side of the raw material lump where the seed single crystal is inserted; and a second spot laser light irradiating device that irradiates a second spot laser light onto the other end side in the width direction of the portion on the upper side of the raw material lump where the seed single crystal is inserted.

[0099] In this way, by providing a spot laser beam irradiator in addition to the main linear laser beam irradiator and the sub-linear laser beam irradiator, it is possible to reliably form a melted region of a desired size by arbitrarily controlling the relative positions of the first main linear laser beam, the second main linear laser beam, and the first sub-linear laser beam, and the irradiation intensities of the first main linear laser beam, the second main linear laser beam, and the first sub-linear laser beam, and the second sub-linear laser beam, as well as the relative positions of the first spot laser beam, the second spot laser beam, and the irradiation intensities of the first spot laser beam, the second spot laser beam, and the second spot laser beam. This makes it possible to continuously produce high-quality, large-sized thin plate single crystals.

[0100] The thin plate single crystal manufacturing apparatus of the present invention is characterized in that a heat radiation shielding wall is provided above the holding section.

[0101] The provision of such a heat radiation shielding wall can suppress the amount of heat radiation from the upper surface of the raw material block, and furthermore, can suppress an increase in temperature inside the chamber in which the thin plate-shaped single crystal is produced, enabling stable production of the thin plate-shaped single crystal.

[0102] The thin plate single crystal manufacturing apparatus of the present invention is characterized in that the seed single crystal has a facet.

[0103] If the seed single crystal inserted into the melting zone formed on the upper surface of the raw material lump is a seed single crystal having a facet surface, and a thin plate-shaped single crystal is formed on the facet surface of this seed single crystal, a thin plate-shaped single crystal having a crystallographically flat plane can be produced.

[0104] Furthermore, the thin plate single crystal manufacturing apparatus of the present invention is characterized in that the plane that includes the optical axis of the line-shaped laser light and is slightly inclined toward the seed single crystal is inclined by a maximum of 10 degrees toward the seed single crystal with respect to a plane perpendicular to the horizontal direction, which is the movement direction of the holding unit.

[0105] The inclination angle of the plane that is slightly inclined toward the seed single crystal side, which includes the optical axis of the line-shaped laser light, can be adjusted to match the size and position of the line-shaped laser light exit port located on the other side, and is not particularly limited; the inclination angle is a maximum of 10 degrees, preferably a maximum of 7 degrees, and more preferably a maximum of 5 degrees.Within this inclination angle, the reflected light can pass through, avoiding the line-shaped laser light exit port located on the other side.

[0106] The inclination angle can be increased by moving the position (irradiation area) where the line-shaped laser light is irradiated away from the position of the seed single crystal (thin plate-shaped single crystal); however, if the position (irradiation area) where the line-shaped laser light is irradiated away from the position of the seed single crystal (thin plate-shaped single crystal), the temperature of the melt in the melting area decreases as it moves away from the irradiation area, and therefore the temperature of the melt at the insertion position of the seed single crystal will decrease.

[0107] Therefore, in order to stably produce a thin plate-shaped single crystal with a large tilt angle, it is necessary to increase the temperature of the irradiation area, which may cause inconvenience such as intensified evaporation from the melt. Therefore, in reality, it is desirable to limit the tilt angle to a maximum of about 5 degrees.

[0108] The thin plate single crystal of the present invention is characterized by being produced by the above-mentioned thin plate single crystal production apparatus.

[0109] Thin plate single crystals produced by such thin plate single crystal production equipment have crystallographically flat surfaces and are of high quality.

[0110] The thin plate-like single crystal of the present invention is characterized in that the thickness of the thin plate-like single crystal is in the range of 30 to 5,000 μm.

[0111] Thus, thin plate-like single crystals having a thickness in the range of 30 to 5,000 μm, more preferably in the range of 30 to 2,500 μm, and even more preferably in the range of 30 to 1,500 μm, can be continuously produced and long lengths can be achieved.

[0112] According to the present invention, it is possible to provide a thin plate single crystal manufacturing apparatus that can continuously produce high-purity, high-quality thin plate single crystals at low cost and with good operability by irradiating a line-shaped laser beam and moving the raw material block in the depth direction, without the need to use a shielding plate as in the conventional case, even for raw material blocks made of various materials such as metals, semiconductors, and insulators, especially for materials with low thermal conductivity such as oxides.

[0113] FIG. 1 is a schematic diagram of an apparatus for producing a thin plate-shaped single crystal according to an embodiment of the present invention, arranged so that the width direction of the thin plate-shaped single crystal faces the front, and FIG. 1(b) is a schematic diagram of part A in FIG. 1(a) viewed from the side. FIG. 2 is an explanatory diagram for explaining a line-shaped laser beam emitted from a laser beam irradiation device, with FIG. 2(a) being an explanatory diagram showing the line direction of the line-shaped laser beam and the width direction of the raw material block as the front, and FIG. 2(b) being an explanatory diagram showing the thickness direction of the line-shaped laser beam and the depth direction of the raw material block as the front. FIG. 3 is an explanatory diagram for explaining a state in which the optical axis of the main line-shaped laser beam is included in a plane that is slightly inclined toward the seed single crystal with respect to a plane perpendicular to the horizontal direction, which is the movement direction of the holder. FIGS. 4(a) to 4(d) are explanatory diagrams for explaining the production of a thin plate-shaped single crystal by irradiating the main line-shaped laser beam onto the raw material block held in the holder to form a melted region, and then moving the raw material block via a horizontal movement device in the horizontal direction, which is the same as the depth direction of the raw material block. Figures 5(a) to 5(d) are explanatory diagrams illustrating the stable production of high-quality thin plate-shaped single crystals, in which a main linear laser beam is irradiated onto a raw material lump held in a holder to form a melting zone, the raw material lump is moved horizontally in the same horizontal direction as the depth direction of the raw material lump via a horizontal movement device, and a secondary linear laser beam is irradiated onto the vicinity of the portion where the seed single crystal is inserted to form a soaking zone, and the seed single crystal is inserted into this soaking zone. Figure 6 is a schematic diagram showing another embodiment of an elevator device that cuts the produced thin plate-shaped single crystal and stores it in a storage facility. Figure 7 is an explanatory diagram showing the orientations of the raw material lump, seed single crystal, and thin plate-shaped single crystal in this specification. Figures 8(a) to 8(c) are schematic diagrams showing the steps from the formation of a melting zone on the upper surface of a raw material lump made of a material with high thermal conductivity to the production of a thin plate-shaped single crystal in a conventional thin plate-shaped single crystal production device. 9(a) to 9(c) are schematic diagrams showing the steps from the formation of a molten zone on the upper surface of a raw material block made of a material with low thermal conductivity to the production of a thin plate-shaped single crystal in a conventional thin plate-shaped single crystal manufacturing apparatus.

[0114] The thin plate single crystal manufacturing apparatus of the present invention will be described in more detail below with reference to the drawings.

[0115] The thin plate single crystal manufacturing apparatus of the present invention is capable of continuously manufacturing high quality, large thin plate single crystals at low cost, even when using materials with low thermal conductivity such as oxides.

[0116] As shown in FIG. 7 , the directions described in this specification are the three directions (length, width, and height) of the rectangular parallelepiped raw material block 60, referred to as the depth direction, width direction, and height direction. Furthermore, for the thin plate-shaped seed single crystal 50 and thin plate-shaped single crystal 52, the direction of the thin wall is referred to as the thickness direction, and the direction of the plane is referred to as the width direction. The horizontal direction, which is the direction of movement of the holding unit 30, is the same as the depth direction of the raw material block 60. Furthermore, the plane perpendicular to the direction of movement of the holding unit 30 is the same as the plane extending in the width direction of the seed single crystal 50 or thin plate-shaped single crystal 52. <Thin Plate Single Crystal Manufacturing Apparatus 10> In the thin plate-shaped single crystal manufacturing apparatus 10 according to an embodiment of the present invention, as shown in FIG. 1 , a holding unit 30 is disposed in a chamber 20, and a raw material block 60 for manufacturing a thin plate-shaped single crystal is held in this holding unit 30. The shape of the raw material block 60 is preferably a rectangular parallelepiped or a cube, and when held by the holding part 30, the upper surface 62 of the raw material block 60 is horizontal.

[0117] The chamber 20 is equipped with two main line-shaped laser light irradiation devices, a first main line-shaped laser light irradiation device (not shown) and a second main line-shaped laser light irradiation device (not shown), for melting the raw material ingot, and two sub-line-shaped laser light irradiation devices, a first sub-line-shaped laser light irradiation device (not shown) and a second sub-line-shaped laser light irradiation device (not shown), for auxiliary heating, and further equipped with two spot-shaped laser light irradiation devices, a first spot-shaped laser light irradiation device (not shown) and a second spot-shaped laser light irradiation device (not shown), for specifying the lateral size of the thin plate-shaped single crystal 52 to be produced.

[0118] 1 is a schematic diagram of the thin plate single crystal manufacturing apparatus 10 arranged so that the width direction of the thin plate single crystal 52 faces the front, and therefore does not show the emission port of the first spot-shaped laser beam irradiating device and the first spot-shaped laser beam irradiated therefrom, or the emission port of the second spot-shaped laser beam irradiating device and the second spot-shaped laser beam irradiated therefrom. However, they are basically arranged in the same manner as the spot-shaped laser beams 116a, 116b and emission ports 114a, 114b shown in FIG. 8(c).

[0119] The two main line-shaped laser beams (first main line-shaped laser beam 14a, second main line-shaped laser beam 14b) irradiated from the two main line-shaped laser beam irradiating devices, the two sub line-shaped laser beams (first sub line-shaped laser beam 18a, second sub line-shaped laser beam 18b) irradiated from the two sub line-shaped laser beam irradiating devices, and the two spot-shaped laser beams (not shown) irradiated from the two spot-shaped laser beam irradiating devices may be incident into chamber 20 in any manner, but it is preferable that they are incident into chamber 20 through window 22 provided on the top or side (side in Figure 1) of chamber 20 and are irradiated onto the upper surface 62 of raw material lump 60 in chamber 20. In FIG. 1, reference numeral 12a denotes an exit port for the first main line-shaped laser beam 14a, reference numeral 12b denotes an exit port for the second main line-shaped laser beam 14b, reference numeral 16a denotes an exit port for the first sub-line-shaped laser beam 18a, and reference numeral 16b denotes an exit port for the second sub-line-shaped laser beam 18b.

[0120] In addition, in the thin plate single crystal manufacturing apparatus 10 of the present invention, the holding section 30 is equipped with a horizontal movement device 40 that moves the raw material block 60 in the same horizontal direction (from the front to the back, or from the back to the front in Figure 1) as the depth direction of the raw material block 60 (from one end 62a to the other end 62b of the raw material block 60, or from the other end 62b to the one end 62a).

[0121] The horizontal movement device 40 is composed of a frame 42 and a roller section 44 connected vertically via a shaft 46, and is configured to be able to move the bottom surface 64 of the chamber 20 in a horizontal direction (from one end 62a to the other end 62b of the raw material block 60, or from the other end 62b to the one end 62a; in Figure 1, from the front to the back, or from the back to the front).

[0122] The amount and speed of movement of holding unit 30 by horizontal moving device 40 can be controlled by control unit 48. Shaft 46 of horizontal moving device 40 also functions as up / down moving device 86, which moves holding unit 30 in the up / down direction, so that when thin plate-shaped single crystals 52 are continuously produced by irradiating upper surface 62 of raw material lump 60 with main line-shaped laser beams 14a, 14b, sub line-shaped laser beams 18a, 18b, and spot-shaped laser beam (not shown), even if the height of melting zone 90 gradually changes, the up / down position of melting zone 90 can always be kept constant by moving raw material lump 60 in the up / down direction.

[0123] Furthermore, horizontal movement device 40 is preferably a linear actuator that converts the rotational motion of an electric motor into linear motion. A linear actuator makes it easy to adjust the speed at which holding unit 30 is moved horizontally (in the depth direction), and is less likely to generate vibration, so the melt formed in melting zone 90 on upper surface 62 of raw material lump 60 does not spill over from upper surface 62. Therefore, the melt remains held on upper surface 62 by surface tension, allowing stable and continuous growth of thin plate-shaped single crystal 52.

[0124] In addition to linear actuators, the structure is not particularly limited to a linear actuator, and may be, for example, a structure in which the holding portion 30 moves horizontally (depthwise) on a roller conveyor (not shown), as long as the structure can move the raw material block 60 horizontally (from one end 62a of the raw material block 60 to the other end 62b, or from the other end 62b to the one end 62a) without the molten liquid formed in the melting area 90 on the upper surface 62 of the raw material block 60 spilling off the upper surface 62, similar to a linear actuator.

[0125] Furthermore, a preheating device 70 for preheating the raw material lump 60 held in the holding section 30 is arranged around the holding section 30 (on the sides and bottom in this embodiment).

[0126] Meanwhile, above the chamber 20, there is provided an elevator device 80 which immerses the lower side of a thin plate-shaped seed single crystal 50 into a molten area 90 formed on the surface of the upper side 62 of the raw material lump 60 by melting the raw material using two main line-shaped laser beams 14a, 14b, two sub line-shaped laser beams 18a, 18b, and two spot-shaped laser beams (not shown), and pulls the seed single crystal 50 upward from the immersed state, and further continuously pulls up the thin plate-shaped single crystal 52 produced together with the seed single crystal 50 via the joint 54.

[0127] Any type of lifting device 80 may be used, but for example, a winding and storage device 82 may be used which continuously winds up and stores the thin plate-shaped single crystal 52 produced together with the seed single crystal 50 in a roll shape.

[0128] The winding and storage device 82 has a winding reel 84 that continuously winds up and stores the produced thin plate-like single crystal 52, and a rotating device 83 that rotates the winding reel 84. In the figure, reference numeral 85 denotes a rotating roller that serves as a guide when the thin plate-like single crystal 52 is continuously wound onto the winding reel 84. With such a winding and storage device 82, when the produced thin plate-like single crystal 52 has a thickness of several hundred μm, it is possible to continuously wind up an ultra-long thin plate-like single crystal 52 reaching a length of several kilometers.

[0129] In addition, it is preferable that the first spot-shaped laser light (not shown) and the second spot-shaped laser light (not shown), which determine the width of the thin plate-shaped single crystal 52, are configured to be irradiated at any angle from the thickness direction of the thin plate-shaped single crystal 52, regardless of the four optical paths in total, namely the two main line-shaped laser light beams 14a, 14b and the two sub line-shaped laser light beams 18a, 18b.

[0130] 2(a) and 2(b), the main line-shaped laser beam 14 (first main line-shaped laser beam 14a, second main line-shaped laser beam 14b) is irradiated in a direction limited to include the optical axes of the main line-shaped laser beam 14 (first main line-shaped laser beam 14a, second main line-shaped laser beam 14b) within a plane perpendicular to the horizontal direction (depth direction), which is the moving direction of the holder 30. Note that reference numeral 12 in Fig. 2 denotes an exit port of the main line-shaped laser beam 14.

[0131] The main linear laser beam 14 is irradiated onto an upper surface 62 of the raw material lump 60 from diagonally above the raw material lump 60. In Figure 2(a) , the main linear laser beam 14 is irradiated onto a predetermined position (irradiation area) on the upper surface 62 of the raw material lump 60 (the thin plate-shaped single crystal 52 to be produced) from diagonally above left in the width direction of the raw material lump 60, thereby forming a melted area 90, and reflected light 19 reflected by the melt surface of the melted area 90 travels diagonally above right in the width direction.

[0132] 2(a) and 2(b) show only the main linear laser beam 14, but similarly, the sub-linear laser beams (first sub-linear laser beam 18a, second sub-linear laser beam 18b) are also irradiated in a limited direction so that the optical axes of the sub-linear laser beams (first sub-linear laser beam 18a, second sub-linear laser beam 18b) are included in a plane perpendicular to the horizontal direction (depth direction), which is the movement direction of the holding portion 30.

[0133] The sub-line laser beams (first sub-line laser beam 18a, second sub-line laser beam 18b) are also irradiated onto the upper surface 62 of the raw material lump 60 from diagonally above the raw material lump 60.

[0134] In this way, the optical axis of the reflected light 19 reflected on the surface of the melt in the melted region 90, like the optical axis of the main linear laser beam 14 and the optical axes of the sub-linear laser beams (first sub-linear laser beam 18a, second sub-linear laser beam 18b), is contained in a plane perpendicular to the horizontal direction (depth direction) which is the direction of movement of the raw material lump 60. Therefore, the reflected light 19 is less likely to hit the seed single crystal 50 or the thin plate-like single crystal 52 to be produced, and the thin plate-like single crystal 52 can be produced continuously with a good yield.

[0135] 2(b), when the thickness of the main line-shaped laser beam 14 is constant as in the thin plate single crystal manufacturing apparatus 10 of the present invention, the reflected light 19 travels with the same thickness as the optical path at the time of irradiation of the main line-shaped laser beam 14, and therefore it is possible to prevent the reflected light 19 from impinging on the seed single crystal 50 or the thin plate single crystal 52 being manufactured. Of course, the same applies to the sub-line-shaped laser beams (first sub-line-shaped laser beam 18a, second sub-line-shaped laser beam 18b).

[0136] Therefore, in the thin plate single crystal manufacturing apparatus 10 of the present invention, it is preferable that the thickness of the main line-shaped laser beam 14 and the thickness of the sub-line-shaped laser beams (first sub-line-shaped laser beam 18a, second sub-line-shaped laser beam 18b) are as constant as possible.

[0137] 2(b), the present specification mainly illustrates a case in which the optical axis of the main linear laser beam 14 and the optical axes of the sub-linear laser beams (first sub-linear laser beam 18a and second sub-linear laser beam 18b) are included in a plane perpendicular to the horizontal direction (depth direction), which is the movement direction of the holder. In other words, when the depth direction is the front, the main linear laser beam 14 and the sub-linear laser beams (first sub-linear laser beam 18a and second sub-linear laser beam 18b) are irradiated vertically downward, and reflected light 19 is emitted vertically upward.

[0138] However, as shown in Figure 3, the optical axis of the main line-shaped laser beam 14 and the optical axes of the sub-line-shaped laser beams (first sub-line-shaped laser beam 18a, second sub-line-shaped laser beam 18b) may be included in a plane that is slightly inclined toward the seed single crystal 50 with respect to a plane perpendicular to the horizontal direction (depth direction), which is the movement direction of the holding part.

[0139] The tilt angle θ of the plane including the optical axis of the main linear laser beam 14 (first main linear laser beam 14a) and the optical axis of the sub-linear laser beam 18 (first sub-linear laser beam 18a) may be adjusted to match the size and position of the optical axis of the main linear laser beam 14 (second main linear laser beam 14b) and the exit port of the sub-linear laser beam 18 (second sub-linear laser beam 18b) arranged on the other side, and is not particularly limited, and the tilt angle θ is a maximum of 10 degrees, preferably a maximum of 7 degrees, and more preferably a maximum of 5 degrees. Within this tilt angle θ, the reflected light 19 can pass through while avoiding the optical axis of the main linear laser beam 14 (second main linear laser beam 14b) and the exit port of the sub-linear laser beam 18 (second sub-linear laser beam 18b) arranged on the other side.

[0140] Furthermore, the inclination angle θ can be increased by moving the positions of the irradiation area of ​​the main line-shaped laser beam 14 and the irradiation area of ​​the sub-line-shaped laser beam 18 away from the position of the seed single crystal 50 (thin plate-shaped single crystal 52). However, if the positions (irradiation areas) where the main line-shaped laser beam 14 and the sub-line-shaped laser beam 18 are irradiated are moved away from the position of the seed single crystal 50 (thin plate-shaped single crystal 52), the temperature of the melt in the melting area 90 decreases as it moves away from the irradiation area, and therefore the temperature of the melt at the insertion position of the seed single crystal 50 decreases.

[0141] Therefore, in order to stably produce the thin plate single crystal 52 with a large tilt angle θ, it is necessary to raise the temperature of the position (irradiation area) irradiated with the main line-shaped laser beam 14 and the sub line-shaped laser beam 18. However, doing so may cause inconvenience such as intensified evaporation from the melt. Therefore, in reality, it is desirable to limit the tilt angle θ to a maximum of about 5 degrees.

[0142] 3 shows only the optical axis of the main line-shaped laser beam 14, the same applies to the sub-line-shaped laser beams (first sub-line-shaped laser beam 18a and second sub-line-shaped laser beam 18b). The symbol θ in FIG. 3 represents the tilt angle.

[0143] That is, if the optical axis of the main line-shaped laser beam 14 and the optical axes of the sub-line-shaped laser beams (first sub-line-shaped laser beam 18 a, second sub-line-shaped laser beam 18 b) are included in a plane that is slightly inclined toward the seed single crystal 50 with respect to a plane perpendicular to the horizontal direction (depth direction), which is the movement direction of the holder 30, the reflected light 19 will travel in a direction away from the seed single crystal 50. Therefore, it is possible to reliably prevent the reflected light 19 from hitting the thin plate-shaped single crystal 52 to be manufactured.

[0144] In Figure 2(a), the case is shown in which the exit port 12 for the main linear laser beam 14 is arranged only on one side in the width direction of the raw material lump 60 (the thin plate-shaped single crystal 52 to be produced), and the reflected light 19 reflected by the melting area 90 travels to the other side. However, although not shown, it is also possible to arrange the exit port 12 for the main linear laser beam 14 on both sides in the width direction of the raw material lump 60 (the thin plate-shaped single crystal 52 to be produced) and irradiate the main linear laser beam 14 at the same position (irradiation area) from both sides, thereby producing a large thin plate-shaped single crystal 52.

[0145] In this case, by appropriately adjusting the positions of the exit port 12 of the main linear laser beam 14 arranged on one side in the width direction of the raw material lump 60 (the thin plate-shaped single crystal 52 to be produced) and the exit port 12 of the main linear laser beam 14 arranged on the other side, as well as the angle of inclination θ, which is slightly inclined toward the seed single crystal 50 side (the thin plate-shaped single crystal 52 side), between one side and the other side, it is possible to prevent the reflected light 19 of the main linear laser beam 14 irradiated from one side on the melt surface of the molten region 90 from irradiating the exit port 12 of the main linear laser beam 14 arranged on the other side. Therefore, a large thin plate-shaped single crystal 52 can be stably produced.

[0146] Furthermore, due to the structure of the thin plate single crystal manufacturing apparatus 10, the seed single crystal 50 (thin plate single crystal 52) is located directly next to the exit port of each line-shaped laser light, so there is almost no room to tilt the position of the exit port of each line-shaped laser light toward the seed single crystal 50 (thin plate single crystal 52), and the maximum inclination is limited to 5 degrees.

[0147] Here, it is not necessary to select either one of the two options as to whether the optical axis of the main line-shaped laser beam 14 and the optical axis of the sub line-shaped laser beam are included within a plane perpendicular to the horizontal direction (depth direction), which is the movement direction of the holding unit, or whether the optical axis of the main line-shaped laser beam 14 and the optical axis of the sub line-shaped laser beam are included within a plane slightly inclined toward the seed single crystal 50 with respect to the plane perpendicular to the horizontal direction (depth direction), which is the movement direction of the holding unit.

[0148] For example, the optical axis of the main linear laser beam 14 may be included in a plane perpendicular to the horizontal direction (depth direction), and the optical axis of the sub-linear laser beam may be included in a plane slightly inclined toward the seed single crystal 50 with respect to the plane perpendicular to the horizontal direction (depth direction). Alternatively, a first main linear laser beam 14a and a second main linear laser beam 14b, which will be described later, may be the same or different, and furthermore, a first sub-linear laser beam and a second sub-linear laser beam may be the same or different.

[0149] Next, the enlargement of the size of the melted region 90 of the raw material lump 60 while moving the raw material lump 60 in the depth direction by the horizontal moving device 40 will be described.

[0150] First, as shown in Figure 4(a), when the first main linear laser beam 14a is irradiated onto the upper surface 62 of the raw material lump 60, the area of ​​the upper surface 62 of the raw material lump 60 irradiated with the first main linear laser beam 14a gradually melts, forming a melted area 90.

[0151] Next, as shown in Figure 4(b), the raw material block 60 held in the holding section 30 can be moved from one end 62a of the raw material block 60 toward the other end 62b (to the right) via the horizontal movement device 40, thereby expanding the melting area 90 to the right.

[0152] The size of the melted region 90 can be controlled by adjusting the intensity of the irradiated first main line-shaped laser beam 14 a, the moving speed of the raw material lump 60 , and the preheating temperature of the raw material lump 60 .

[0153] Then, when the thin plate-shaped seed single crystal 50 is immersed in this melted region 90 and pulled up, a thin plate-shaped single crystal 52 can be produced from the lower end of the thin plate-shaped seed single crystal 50 via the joint 54 .

[0154] As the raw material lump 60 continues to move to the right, the melted region 90 reaches one end 62a of the raw material lump 60, as shown in Figure 4(c). At this point, as shown in Figure 4(d), by reversing the direction of movement of the raw material lump 60 from right to left, thin plate-shaped single crystals 52 can be produced continuously.

[0155] During this inversion, in order to prevent the melt from spilling from the upper surface 62 of the raw material lump 60 and to prevent fluctuations in the temperature of the growth interface of the thin plate-shaped single crystal 52, the irradiation of the first main line-shaped laser beam 14a is stopped and the second main line-shaped laser beam 14b is irradiated to suppress temperature fluctuations of the melt.

[0156] If the raw material lump 60 continues to move to the left, the melting zone 90 will reach the other end 62b of the raw material lump 60, and the direction of movement of the raw material lump 60 will again be reversed from left to right, the irradiation of the second main linear laser beam 14b will be stopped, and the first main linear laser beam 14a will be irradiated, thereby suppressing temperature fluctuations in the melt and enabling stable and continuous production of thin plate-shaped single crystals 52.

[0157] By moving the raw material lump 60 rightward in this manner, each time the melting zone 90 reaches one end 62a of the raw material lump 60, the direction of movement of the raw material lump 60 is reversed leftward, and when the melting zone 90 reaches the other end 62b of the raw material lump 60, the direction of movement of the raw material lump 60 is reversed rightward, and by repeating this process, thin plate-shaped single crystals 52 can be continuously produced until the height of the large raw material lump 60 is reached. As a result, ultra-long thin plate-shaped single crystals 52 can be produced.

[0158] Next, a method will be described in which a soaking zone is formed in the vicinity of the portion of the melted zone formed by irradiation with the main line-shaped laser beam where the seed single crystal is inserted, thereby enabling stable production of a thin plate-shaped single crystal.

[0159] 4(a) to 4(d), thin plate single crystal 52 is produced from melted region 90 formed by irradiating raw material ingot 60 with main line-shaped laser beams 14a and 14b. However, in this method, the surface temperature of melted region 90 formed is highest at the portion irradiated with main line-shaped laser beams 14a and 14b, and the surface temperature decreases steadily with increasing distance from this portion.

[0160] Although it is possible to produce the thin plate single crystal 52 even in this state, in order to produce a stable thin plate single crystal 52, it is desirable that the region in which the thin plate single crystal 52 is produced be soaked.

[0161] Therefore, as shown in Figure 5, it is effective to irradiate the second sub-line-shaped laser beam 18b on the side opposite to the irradiation area of ​​the first main line-shaped laser beam 14a at the location where the thin-plate-shaped seed single crystal 50 is inserted, thereby raising the temperature of the irradiated area and maintaining the temperature in the vicinity of the location where the seed single crystal 50 is inserted in a uniform temperature state.

[0162] That is, as shown in Figure 5(a), the exit 12a of the first main line-shaped laser beam 14a, the exit 12b of the second main line-shaped laser beam 14b, the exit 16a of the first sub-line-shaped laser beam 18a, and the exit 16b of the second sub-line-shaped laser beam 18b are arranged near the site where the seed single crystal 50 is inserted.

[0163] After the first main linear laser beam 14a is irradiated onto the upper surface 62 of the raw material block 60 to form a melted area 90, the raw material block 60 is moved to the right as shown in Figure 5(b), and the melted area 90 expands to the right.

[0164] Next, by irradiating the second sub-line-shaped laser beam 18b, a soaking zone 91 can be formed in the vicinity of the portion where the seed single crystal 50 is inserted. The seed single crystal 50 is inserted into this soaking zone 91, and pulled upward via the joint 54 while producing the thin plate-shaped single crystal 52, whereby the high-quality thin plate-shaped single crystal 52 can be stably produced.

[0165] As the raw material lump 60 continues to move further to the right, the melting zone 90 reaches one end 62a (the left end in this figure) of the raw material lump 60, as shown in Fig. 5(c). At this position, the direction of movement of the raw material lump 60 is reversed, and the raw material lump 60 is moved leftward, as shown in Fig. 5(d). The irradiation of the first main linear laser beam 14a and the second sub-linear laser beam 18b is stopped, and instead the second main linear laser beam 14b and the first sub-linear laser beam 18a are irradiated. When reversing the direction of movement of the raw material lump 60, it is desirable to minimize temperature fluctuations in the soaking zone 91.

[0166] If the raw material block 60 continues to move to the left, the melting zone 90 will reach the other end 62b of the raw material block 60, and the direction of movement of the raw material block 60 will again be reversed from left to right. This time, the irradiation of the second main linear laser beam 14b and the first sub-linear laser beam 18a will be stopped, and instead the first main linear laser beam 14a and the second sub-linear laser beam 18b will be irradiated, thereby enabling the stable and continuous production of thin plate-shaped single crystals 52.

[0167] By moving the raw material lump 60 rightward in this manner, each time the melting zone 90 reaches one end 62a of the raw material lump 60, the direction of movement of the raw material lump 60 is reversed leftward, and when the melting zone 90 reaches the other end 62b of the raw material lump 60, the direction of movement of the raw material lump 60 is reversed rightward, and by repeating this process, thin plate-shaped single crystals 52 can be continuously produced until the height of the large raw material lump 60 is reached. As a result, ultra-long thin plate-shaped single crystals 52 can be produced.

[0168] 4 and 5, during the above-described operation, a first spot-shaped laser beam (not shown) and a second spot-shaped laser beam (not shown) are irradiated onto both ends in the width direction of the thin plate-shaped single crystal 52 in order to define the width of the thin plate-shaped single crystal 52 to be produced. It is preferable that the first spot-shaped laser beam (not shown) and the second spot-shaped laser beam (not shown) are continuously irradiated during the above-described operation.

[0169] By adjusting the irradiation intensity of the main line-shaped laser beams 14a, 14b and the sub line-shaped laser beams 18a, 18b, the speed at which the raw material lump 60 is moved, the preheating temperature of the raw material lump 60, etc., according to the single crystal material of the raw material lump 60, a stable soaking area 91 can be formed, and high-quality, large, thin plate-shaped single crystals 52 can be continuously produced even from materials with low thermal conductivity such as oxides.

[0170] The above method maintains a constant amount of raw material melt, which means that the so-called solvent migration method is optimally applied, making it possible to produce a high-quality thin plate-shaped single crystal 52 with an optimal and homogeneous dopant concentration, which was previously considered impossible with conventional pulling methods.

[0171] Furthermore, in the thin plate single crystal manufacturing apparatus 10 of this embodiment, the main line-shaped laser beams 14a, 14b, the sub line-shaped laser beams 18a, 18b, and also a spot-shaped laser beam (not shown) are used to continuously manufacture the thin plate single crystal 52, and at this time, it is preferable to preheat the raw material lump 60 to near its melting point using a preheating device 70, as shown in Fig. 1. The preheating device 70 is preferably disposed so as to surround the raw material lump 60 when the raw material lump 60 is held in the holding part 30.

[0172] By preheating the raw material lump 60 to near its melting point using a preheating device 70 prior to irradiating the upper surface 62 of the raw material lump 60 with the main line-shaped laser beams 14a, 14b, the sub line-shaped laser beams 18a, 18b, and the spot laser beam (not shown), the amount of irradiation of the main line-shaped laser beams 14a, 14b can be significantly reduced compared to the amount of irradiation of the main line-shaped laser beams 14a, 14b when the preheating device 70 is not used.

[0173] Furthermore, by using the preheating device 70, it is possible to replace an expensive, high-power main line-shaped laser light irradiation device with an inexpensive, low-power main line-shaped laser light irradiation device, which not only reduces the manufacturing cost of the thin plate-shaped single crystal 52 but also reduces the temperature fluctuation range of the raw material block 60, thereby preventing undesirable phenomena such as cracks occurring in the raw material block 60 due to sudden temperature fluctuations.

[0174] 1, it is desirable for preheating device 70 to heat raw material lump 60 from either the side or the bottom, as necessary. By maintaining a uniform temperature throughout raw material lump 60 with preheating device 70, it is possible to stabilize the size of melted region 90 formed by irradiation with main line-shaped laser beams 14a and 14b, and it is also possible to stabilize soaked region 91 formed by irradiation with sub line-shaped laser beams 18a and 18b and accurately regulate the lateral size of thin plate-shaped single crystal 52 defined by irradiation with spot-shaped laser beam (not shown).

[0175] Such preheating device 70 may be, for example, a known resistance heating furnace using materials such as high-purity silicon, carbon, molybdenum, etc. Alternatively, a high-frequency induction heating device, an infrared irradiation device, etc. may also be used, and is not particularly limited.

[0176] Furthermore, the thin plate single crystal manufacturing apparatus 10 of the present invention preferably has a heat radiation shielding wall 72 provided above the holding part 30. If the heat radiation shielding wall 72 is provided in this manner, the amount of heat radiation from the upper surface 62 of the raw material ingot 60 can be suppressed, and an increase in the temperature inside the chamber 20 in which the thin plate single crystal 52 is manufactured can be suppressed, allowing the thin plate single crystal 52 to be manufactured stably.

[0177] As described above, by using the thin plate single crystal manufacturing apparatus 10 of the present invention, thin plate single crystals 52 can be continuously manufactured, but as the thin plate single crystals 52 are continuously manufactured, the position of the upper surface 62 of the raw material ingot 60 will drop. If this happens, it will be necessary to control the irradiation positions of the main line-shaped laser beams 14a, 14b, the sub line-shaped laser beams 18a, 18b, and the spot-shaped laser beam (not shown) so that they are at the desired positions.

[0178] In this embodiment, as shown in Figure 1, the shaft 46 of the horizontal movement device 40 attached to the holding section 30 that holds the raw material block 60 is equipped with an up-down movement device 86 that adjusts the vertical position of the holding section 30.

[0179] By providing such an up-and-down moving device 86, even if the position of the upper surface 62 of the raw material block 60 drops as the continuously produced thin plate-shaped single crystal 52 is pulled up, the holding portion 30 can be raised to maintain the position of the upper surface 62 of the raw material block 60 at the same position as its original position, and the liquid surface position of the melt in the melting zone 90 can always be kept at the same position.

[0180] Therefore, it is only necessary to control the vertical movement device 86 so that the main line-shaped laser beams 14a, 14b, the sub line-shaped laser beams 18a, 18b, and the spot-shaped laser beam (not shown) are always irradiated at the same height position on the upper surface 62 of the raw material block 60, and thin plate-shaped single crystals 52 can be produced continuously with stability and high yield.

[0181] According to the present invention, a melting zone 90 is formed while the raw material lump 60 is moved horizontally (depth direction) by the horizontal movement device 40, and the optical axes of the main linear laser beams 14a, 14b and the secondary linear laser beams 18a, 18b irradiated onto the upper surface 62 of the raw material lump 60 are included in a plane perpendicular to the horizontal direction (depth direction), which is the movement direction of the raw material lump 60.Therefore, a thin plate single crystal manufacturing apparatus 10 can be provided that can form a melting zone 90 of the required size for raw material lump 60 made of various materials such as metals, semiconductors, and insulators, especially for materials with low thermal conductivity such as oxides, without using the shielding plates 140a, 140b that were previously used.

[0182] Furthermore, if the output of a commercially available laser light irradiation device (e.g., a laser oscillator) is insufficient to produce a large thin plate-shaped single crystal 52, multiple laser light irradiation devices can be used, with each line-shaped laser light emission port 12 positioned on both sides of the width direction of the raw material lump 60 (the thin plate-shaped single crystal 52 to be produced), and the line-shaped laser light emitted from both sides can be irradiated onto the same position (irradiation area) to form a melted area 90 of the desired size, thereby producing a large thin plate-shaped single crystal 52.

[0183] In such a case, by irradiating the multiple line-shaped laser beams so that their optical axes are contained within a plane inclined toward the seed single crystal 50 (thin plate-shaped single crystal 52) with respect to a plane perpendicular to the horizontal direction, it is possible to avoid the reflected light directly hitting the exit port of another line-shaped laser beam located on the other side.

[0184] Therefore, the thin plate single crystal manufacturing apparatus 10 of the present invention can continuously manufacture high-purity, high-quality, large thin plate single crystals 52 at low cost and with good operability.

[0185] Although the thin plate single crystal manufacturing apparatus 10 of the present invention has been described above, the thin plate single crystal manufacturing apparatus 10 of the present invention is not limited to the above-described embodiment.

[0186] For example, as shown in FIG. 6, the lifting device 80 may be provided with a cutting and storage device 88 that continuously pulls up the produced thin plate-shaped single crystal 52 while cutting it into pieces of a predetermined length and storing them.

[0187] The cutting and storage device 88 is configured so that the thin plate single crystal 52 can be continuously pulled upward via a plurality of rollers 92, while being cut into predetermined lengths in a cutting section 94. The cut thin plate single crystals 52 of the desired length are sent further upward to a storage section 96 and stored one by one. With the cutting and storage device 88 configured in this manner, the thin plate single crystal 52 can be cut into lengths of, for example, about 2 m and stored, allowing the thin plate single crystal 52 produced by the thin plate single crystal production apparatus 10 of the present invention to be suitably used in existing semiconductor-related equipment.

[0188] Furthermore, in the above-described embodiment, a spot laser light irradiation device (not shown) is used to determine the width (the size in the width direction perpendicular to the thickness direction) of the thin plate-shaped single crystal 52, but it is also possible to determine the width (the size in the width direction perpendicular to the thickness direction) of the thin plate-shaped single crystal 52 using a main line-shaped laser light irradiation device without using a spot laser light irradiation device (not shown).

[0189] Furthermore, the horizontal movement device 40 may be configured to not only move in the horizontal direction (depth direction), but also vibrate or slightly swing the holding part 30. By adding such an operation, vibration is applied to the melting region 90, and when producing the thin plate-like single crystal 52, non-uniformity in the concentration of additives formed near the solid-liquid interface can be reduced, thereby suppressing cell growth and enabling a higher pulling speed when producing the thin plate-like single crystal 52, thereby reducing the cost of producing the thin plate-like single crystal 52.

[0190] Furthermore, the positioning of the exit port 12 of the main line-shaped laser beam 14 may be biased to one side in the width direction of the raw material block 60 (thin plate-shaped single crystal 52 to be manufactured), or may be positioned on both sides, depending on the output of the laser beam irradiation device required for the thin plate-shaped single crystal 52 to be manufactured.

[0191] Furthermore, even when both the main line-shaped laser beam 14 and the sub line-shaped laser beam 18 are used, they may be provided biased to one side in the width direction of the raw material block 60 (the thin plate-shaped single crystal 52 to be manufactured), provided on both sides, or a mixture of these.

[0192] In other words, for example, the main line-shaped laser beam 14 may be biased to one side in the width direction of the raw material block 60 (the thin plate-shaped single crystal 52 to be manufactured), and the sub-line-shaped laser beam 18 may be provided on both sides in the width direction of the raw material block 60 (the thin plate-shaped single crystal 52 to be manufactured), and the design can be modified as appropriate.

[0193] In addition, various modifications are possible within the scope of the purpose of the present invention, such as the use of the technical content described in the thin plate single crystal manufacturing apparatus and thin plate single crystal manufacturing method already filed by the applicant (for example, JP 2023-025811 A).

[0194] REFERENCE SIGNS LIST 10 Thin plate single crystal manufacturing apparatus 12 Emission port 12a Emission port for first main linear laser beam 12b Emission port for second main linear laser beam 14 Main linear laser beam 14a First main linear laser beam 14b Second main linear laser beam 16a Emission port for first sub-linear laser beam 16b Emission port for second sub-linear laser beam 18 Sub-linear laser beam 18a First sub-linear laser beam 18b Second sub-linear laser beam 19 Reflected light 20 Chamber 22 Window 30 Holding unit 40 Horizontal movement device 42 Stand 44 Roller unit 46 Shaft 48 Control unit 50 Seed single crystal 52 Thin plate single crystal 54 Joint unit 60 Raw material lump 62 Upper surface 62a One end 62b Other end 64 Bottom surface 70 Preheating device 72 Heat radiation shielding wall 80 Elevating device 82 Winding and storage device 83 Rotating device 84 Winding reel 85 Rotating roller 86 Up and down moving device 88 Cutting and storage device 90 Melting area 91 Soaking area 92 Roller 94 Cutting section 96 Storage section 100 Raw material lump 102 Upper surface 110a Exit port 110b Exit port 112a Laser beam 112b Laser beam 114a Exit port 114b Exit port 116a Spot-shaped laser beam 116b Spot-shaped laser beam 120 Melting area 120a Melting area 120b Melting area 130 Thin plate-shaped single crystal 132 Joint section 134 Seed single crystal 140a Shielding plate 140b Shield plate θ Inclination angle

Claims

1. A thin plate-shaped single crystal manufacturing apparatus comprising at least: a holding unit for holding a raw material lump; a laser light irradiator for irradiating a laser light onto an upper side of the raw material lump held by the holding unit to melt the surface of the upper side and form a melted region; and a lifting device for immersing a thin plate-shaped seed single crystal in the melted region formed on the upper side of the raw material lump and lifting the seed single crystal upward from the immersed state, wherein by immersing the seed single crystal in the melting region via the lifting device, single crystal growth begins from the lower side of the immersed seed single crystal, and by further lifting the seed single crystal upward via the lifting device, thin plate-shaped single crystals are continuously manufactured, wherein the thin plate-shaped single crystal manufacturing apparatus comprises a horizontal movement device for moving the holding unit for holding the raw material lump in the horizontal direction which is the same as the thickness direction of the seed single crystal depending on the manufacturing status of the thin plate-shaped single crystal, and further wherein the laser light irradiated from the laser light irradiator is a line-shaped laser light, The thin plate single crystal manufacturing apparatus is characterized in that the optical axis of the line-shaped laser light is included within a plane perpendicular to the horizontal direction, which is the movement direction of the holding part moved by the horizontal movement device, or the optical axis of the line-shaped laser light is included within a plane that is slightly inclined toward the seed single crystal with respect to the plane perpendicular to the horizontal direction, which is the movement direction of the holding part moved by the horizontal movement device.

2. The thin plate single crystal manufacturing apparatus according to claim 1, characterized in that the laser light irradiation device comprises a main line-shaped laser light irradiation device used to form a melted area on the upper surface of the raw material lump, and a sub-line-shaped laser light irradiation device used to form a soaking area within the formed melted area.

3. The thin plate single crystal manufacturing apparatus according to claim 1, wherein the raw material block is a rectangular parallelepiped or a cube.

4. The thin plate single crystal manufacturing apparatus as described in claim 2, characterized in that, when the raw material block is held in the holding section, the main line-shaped laser light is configured to irradiate the upper surface of the raw material block from diagonally above the raw material block.

5. The thin plate single crystal manufacturing apparatus of claim 1, characterized in that, when the raw material block is held in the holding section, the horizontal movement device is configured to reverse the movement direction of the raw material block when the melting area reaches one end of the depth direction of the upper surface of the raw material block due to the movement of the holding section, and to reverse the movement direction of the raw material block when the melting area reaches the other end of the depth direction of the upper surface of the raw material block, and to repeat this operation.

6. The thin plate single crystal manufacturing apparatus according to claim 1, characterized in that a preheating device for preheating the raw material ingot is disposed around the holding section.

7. The thin plate single crystal manufacturing apparatus according to claim 1, further comprising a vertical movement device for moving said holding part in the vertical direction.

8. The thin plate single crystal manufacturing apparatus according to claim 1, characterized in that the lifting device is a winding and storing device that continuously winds up the manufactured thin plate single crystal in a roll and stores it.

9. The thin plate single crystal manufacturing apparatus according to claim 1, characterized in that the lifting device is a cutting and storage device that pulls up the manufactured thin plate single crystal, cuts it into predetermined lengths, and stores it.

10. The thin plate single crystal manufacturing apparatus according to claim 2, characterized in that when the raw material block is held in the holding section, the main line-shaped laser light irradiated from the main line-shaped laser light irradiating device comprises a first main line-shaped laser light irradiated from one end side of the portion on the upper surface of the raw material block where a seed single crystal is inserted, and a second main line-shaped laser light irradiated from the other end side of the portion on the upper surface of the raw material block where a seed single crystal is inserted.

11. The thin plate single crystal manufacturing apparatus according to claim 2, characterized in that, when the raw material block is held in the holding section, the secondary line-shaped laser light is configured to irradiate the upper surface of the raw material block from diagonally above the raw material block.

12. The thin plate single crystal manufacturing apparatus according to claim 2, characterized in that, when the raw material block is held in the holding section, the sub-line-shaped laser light is a first sub-line-shaped laser light irradiated from one end side of the portion on the upper surface of the raw material block where the seed single crystal is inserted, and a second sub-line-shaped laser light irradiated from the other end side of the portion on the upper surface of the raw material block where the seed single crystal is inserted.

13. The thin plate single crystal manufacturing apparatus according to claim 1, characterized in that it is provided with a spot laser light irradiation device which, when the raw material block is held in the holding section, irradiates spot laser light onto one end and the other end in the width direction of the portion on the upper side of the raw material block where the seed single crystal is inserted.

14. The thin plate single crystal manufacturing apparatus according to claim 13, characterized in that the spot-shaped laser light irradiating device that irradiates the spot-shaped laser light comprises: a first spot-shaped laser light irradiating device that irradiates a first spot-shaped laser light onto one end side in the width direction of the portion on the upper side of the raw material lump where the seed single crystal is inserted; and a second spot-shaped laser light irradiating device that irradiates a second spot-shaped laser light onto the other end side in the width direction of the portion on the upper side of the raw material lump where the seed single crystal is inserted.

15. The thin plate single crystal manufacturing apparatus according to claim 1, wherein a heat radiation shielding wall is provided above the holding section.

16. The thin plate single crystal manufacturing apparatus according to claim 1, wherein the seed single crystal has a facet surface.

17. A thin plate-shaped single crystal according to claim 1, characterized in that the plane containing the optical axis of the line-shaped laser light and slightly inclined toward the seed single crystal is a plane inclined at a maximum of 10 degrees toward the seed single crystal with respect to a plane perpendicular to the horizontal direction, which is the direction of movement of the holding part.

18. A thin plate single crystal produced by the thin plate single crystal production apparatus according to any one of claims 1 to 17.

19. The thin plate-shaped single crystal according to claim 18, characterized in that the thickness of the thin plate-shaped single crystal is within the range of 30 to 5,000 μm.

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