TWI289614B - Method of manufacturing silicon monocrystal and device for manufacturing semiconductor monocrystal - Google Patents

Abstract

A method of manufacturing a silicon monocrystal and a device for manufacturing a semiconductor monocrystal containing silicon monocrystal; the method of manufacturing the silicon monocrystal, comprising the steps of, inside a cultivating furnace (2), disposing a crucible (12) having molten silicon liquid (14) stored therein, disposing upper in-furnace structures (5, 30) so as to surround a cultivated monocrystal (23), and adjusting the flow velocity of the inert gas allowed to flow out of the tip opening part of the upper in-furnace structure (5) when the inert gas passes through a space surrounded by the inner wall of the crucible (12) and the outer wall of the upper in-furnace structures (5, 30) to 6.5 cm/sec. Or higher when the inert gas is discharged to the outside of the cultivating furnace (2) through the space surrounded by the inner and outer walls while the silicon monocrystal (23) is cultivated by the Czochralski method while the inert gas is allowed to flow down from the upper side to a molten silicon liquid level (14a) in the crucible (12) in the upper in-furnace structure (5).

Description

1289614 a7 ___B7 _ V. DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a manufacturing apparatus comprising a method for producing monocrystalline single crystals and a semiconductor single crystal of tantalum single crystal. [Background Art] As a method for producing a semiconductor single crystal, a so-called Czochralski Method (hereinafter referred to as CZ method) is known. In this method, the raw material block is placed in a growth furnace of a single crystal manufacturing apparatus, and the heater disposed around the crucible is heated at a high temperature so that the raw material in the crucible becomes a molten liquid. Then, when the temperature of the molten metal reaches a stable state, the seed crystal adheres to the molten metal surface of the raw material, and then the seed crystal is gradually pulled up, thereby growing a semiconductor single crystal having a predetermined diameter and quality below the seed crystal. Further, in the recent manufacturing apparatus for semiconductor single crystal using the CZ method, development of an automatic device and development of an optical instrument, such as an image pickup device for monitoring the inside of a growth furnace, which is provided outside the growth furnace, for detecting the self-melting liquid An optical type detecting device having a diameter of the pulled-up crystal or an optical detecting device for measuring a temperature of the molten metal or the like is disposed and used. For example, in the case of using an image pickup device, the apparatus main body is attached to the inside of the growth furnace, and the molten steel surface of the raw material inside the growth furnace is transmitted through the furnace observation window provided in the furnace wall or the inside of the growth furnace. Photography is performed with a single crystal growth section. The image data obtained by this photographing is used as the growth control information of the semiconductor single crystal. In the furnace observation furnace, the inside of the growth furnace can be observed by separating the inside and outside of the growth furnace or before the function of the structure in the upper furnace is not damaged, and the paper size is applied to the Chinese national standard (CNS). )A4 size (210 X 297 mm) (·Please read the notes on the back and fill out this page)

1289614 A7 ___B7 _ V. INSTRUCTIONS (2) Measuring method is embedded in transparent glass, and it is necessary to confirm the growth of single crystal through the glass, collect information from the inside of the growth furnace, and process it to make it necessary for single crystal growth. Various controls. On the other hand, in the recent single crystal production, in order to suppress defects in the growth of a single crystal as much as possible, or to increase the cooling rate of the grown single crystal, the single crystal pullup speed and the productivity are improved. I have explored various methods. As a method for efficiently cooling a single crystal pulled up from a raw material melt, generally, the upper furnace structure is disposed so as to surround a single crystal directly above the raw material melt to be supplied from the heater. Or the radiant heat of the molten metal surface is shielded to rapidly cool the crystal. In this case, as the upper structure in the furnace to be used, a cylindrical gas rectifying furnace arranged to hang down from the upper growth furnace and a heat shielding curtain having an inverted conical shape are basically used. The environment inside the furnace and the crystal quality are designed into various shapes. In addition, the purpose of controlling the crystal defects included in the growth of crystals at a low density and increasing the growth rate of crystallization to improve productivity is also aimed at not only shielding the radiant heat from the periphery of the crystal, but also In order to improve the cooling efficiency of crystallization by improving the thermal conductivity of the structure in the furnace and improving the heat insulating structure, the upper structure of the furnace has been discussed, and it has gradually been put into practical use. However, the raw material melt heated by the heater to a high temperature of 1400 ° C or higher is fixed to release evaporate such as SiO (-cerium oxide) into the growth furnace. When the evaporant comes into contact with the relatively low temperature part of the growth furnace, the low temperature part will cause the evaporant to become solid and precipitate, and it will adhere to the furnace wall of the growth furnace or the furnace. The paper scale is applicable to the Chinese National Standard (CNS) A4. Specifications (210 X 297 mm) 1289614 A7 ___B7 _ V. The structure inside the invention (?) gradually accumulates. When the amount of such a deposit is too large, the deposit may peel off during the operation, fall into the raw material melt, or adhere to the growth portion of the single crystal, which may cause crystal defects such as poor discharge, which may hinder the normal operation. The single crystal grows. Moreover, the attachment will erode the member, resulting in a shorter service life of the member, which is also a problem. In addition, when the evaporating material from the raw material melt adheres to the observation window in the furnace, the glass is not blurred, and the operator cannot observe the single crystal growth portion, and the measurement of the optical measuring instrument attached to the outside of the growth furnace is performed. It will also become unstable, and the worst case is the result of the state in which the growth of the single crystal growth is impossible. In the conventional single crystal manufacturing apparatus using the CZ method, in order to avoid the above-mentioned undesired situation, in the growth of a single crystal, a low-reactivity Ar (argon) having a relatively constant flow rate to the inside of the growth furnace is used. An inert gas such as a gas causes the vaporized material from the raw material melt to be discharged together with the inert gas to the outside of the growth furnace. In particular, it takes a considerable time for the growth of a single crystal to be pulled up for a large diameter long single crystal, or a so-called multiple pull-up method (Multiple Czochalski Method), after growing a single crystal, the raw material in the crucible is not melted. The liquid is solidified, but the raw material block is refilled in the crucible, and the evaporating material from the raw material melt is efficiently discharged to the single crystal of the method of growing a plurality of semiconductor single crystals from a vortex. Outside the growth furnace, it is important to maintain the stability of the furnace in the long-term growth period from the start to the end of the operation. However, in order to seek for the low density of crystal defects included in single crystal and 5 degrees, the Chinese National Standard (CNS) A4 specification (210 X 297 mil) is applied. -- Γ Please read the notes on the back and fill out this page. ) -------- order --------- line

A7 1289614 _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ The result, on the contrary, promotes the attachment of the evaporant. Further, the "adhesion of the evaporant to the structure in the upper furnace" tends to be promoted as the size of the single crystal manufacturing apparatus increases. The specific reason for this is that, in a single crystal manufacturing apparatus for growing large single crystals, 'the use of a large diameter to maintain a large amount of raw material melt, or to grow based on the need to maintain a large diameter. The furnace body must also be enlarged. 'The result is that it is easy to become a lower temperature part away from the heat source. An object of the present invention is to provide a method for producing monocrystalline single crystals. In the growth of a single crystal by a CZ method, it is possible to effectively suppress evaporation of an evaporate from a crucible melt directly above the crucible melt. The structure is precipitated and adhered, and the operation can be continued for a long time without hindering, for example, the growth of single crystals and the in-furnace observation required for instrument control; in addition, in order to reasonably implement the method, the present invention provides A semiconductor single crystal manufacturing apparatus capable of appropriately refluxing an inert gas flowing inside a growth furnace when a single crystal grows, and even preventing or even suppressing evaporation of evaporate released from a raw material melt in a growth furnace, It can be discharged evenly and quickly to the outside of the growth furnace. [Invention of the Invention] In order to solve the above problems, the method for producing a single crystal according to the present invention is characterized in that inside a growth furnace, a crucible containing a crucible melt is disposed, and a single crystal is grown around the growth. The way to set the upper furnace structure' in the upper furnace structure allows the inert gas to move from above to the 坩埚6. This paper scale applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) — — — — — — — ^ ·11111111 C Please read the notes on the back and fill in again - write this page) Φ

A7 1289614 ___B7____ V. In the invention description (t), the surface of the molten liquid flows under the surface of the crucible, and the Cleopatra method is used to grow the single crystal, and in the growth of the single crystal, the structure in the upper furnace is allowed. The inert gas flowing out from the opening at the front end is discharged to the outside of the growth furnace through the space surrounded by the inner wall of the crucible and the outer wall of the upper furnace structure, and the flow rate of the inert gas is adjusted when passing through the space. It becomes 6.5cm/sec or more. According to the method of the present invention, the flow rate of the inert gas flowing from the outer wall of the upper furnace structure to the inner wall of the crucible to the inside of the growth furnace after the flow is sent to the molten liquid surface is adjusted to 6.5 cm/sec or more. Increasing the amount of the inert gas convection to the top of the growth furnace can effectively suppress the evaporation of the evaporant from the low temperature portion above the furnace (especially, the cooling effect is lowered and the upper structure in the furnace is lowered) to become an adherent. Further, the flow rate of the inert gas in the present specification is represented by a position where the interval between the inner wall of the crucible and the outer wall of the upper furnace inner structure with respect to the radial direction of the single crystal pull-up shaft is the smallest. In the method of the present invention, it is possible to pass through the furnace observation window formed of a transparent material (for example, heat-resistant glass such as quartz glass) formed in the growth furnace and the upper furnace structure from outside the growth furnace. The state of the inner side of the structure in the upper furnace was optically detected or observed to simultaneously grow the single crystal. According to the configuration of the present invention, even if the temperature of the upper furnace structure in which the observation window portion in the furnace is installed is at a relatively low temperature, the observation window portion in the furnace is less likely to be unfavorably caused by the deposit. In this way, it is possible to ensure the long-term continuous photography of single crystals made by a camera such as a camera, or to use the crystal diameter to detect 7 paper sizes applicable to the Chinese National Standard (CNS) A4 specification (210 X). 297 mm) Γ Please read the precautions on the back and fill out this page), !---- *φ· 1289614 A7 __B7^_ V. Description of invention (&) Measurement by optical detectors of devices, etc. . In particular, in the semiconductor single crystal manufacturing apparatus which detects the diameter of the growth crystallization by detecting the ring (ring) generated at the boundary between the molten metal surface and the crystal, since the observation window is attached and evaporated in the furnace for a long time The measurement error caused by the object can be controlled with high precision diameter, and even the productivity and yield of single crystal can be improved. In addition, since the crystal has a predetermined diameter and is pulled upward, the quality of the entire crystal length is stabilized, and a single crystal which suppresses fluctuations in impurities such as oxygen can be grown. The above-described effects of the present invention are particularly remarkable in the production of large diameter crystals and the pulling of long crystals which require a large amount of time for crystal growth. In particular, even in a large single crystal manufacturing apparatus in which a large-diameter crucible in which 100 kg or more of polycrystalline silicon raw material is melted, which has a diameter of more than 50 cm, can be accommodated in the ceiling portion of the growth furnace body, Can fully exert the above effects. Moreover, even if a multiple pull-up method (that is, a single crystal in which a plurality of crystals are not allowed to be solidified after the single crystal is pulled up and the same raw material is not added to the same crucible, and a single crystal is grown from a quartz crucible) In the middle, a quite satisfactory effect can also be obtained. Next, in the present invention, in order to sufficiently achieve the above effects, the lower limit of the flow rate of the inert gas is set to 6.5 cm/Sec, but if the flow rate is increased to more than necessary, not only waste of inert gas is caused, but also manufacturing. Cost considerations are also undesirable. In view of this, the flow rate of the inert gas flowing out from the space (gap) surrounded by the outer wall of the upper furnace structure and the inner wall of the crucible is preferably not more than 2 〇cm/SeC. Further, the flow rate is preferably set in the range of 6_5 to 8.5 cm/sec. 8 The paper size is applicable to China National Standard (CNS) A4 specification (210 X 297 mm) (please read the notes on the back and fill out this page) Φ Order---- *φ· 1289614 A7 _____ B7___ V. Invention Description (7) Next, the upper furnace structure is disposed as a means for adjusting the thermal history of the grown single crystal, and is disposed around the grown single crystal by the furnace structure located above the molten liquid surface. The radiant heat from the heater or the raw material melt or the like is prevented from being directly transmitted to the crystal. At this time, since the crystal growth portion that is in contact with the molten metal surface of the raw material and the grown single crystal becomes a shadow placed on the upper structure of the furnace directly above the molten liquid, it is quite difficult to directly observe from the outside of the growth furnace. It is particularly effective to provide the observation window portion in the furnace, and the effect of the present invention is more remarkable in view of preventing blurring. Further, the upper furnace structure may be made of a material having good thermal conductivity such as metal or graphite, and the lower end of the structure and the raw material melt surface may be disposed with a gap of only about 5 to 50 mm, and may be arranged on a single crystal. Play this effect immediately after pulling. The heat conductivity and the heat insulating structure of the structure in the upper furnace are improved, and the cooling temperature ambient atmosphere surrounding the single crystal portion of the structure in the upper furnace can be adjusted. In particular, in the case of a furnace structure in which the shape of the upper furnace is reversed by the inert gas blown from the surface of the melt, the inert gas blown from the surface of the melt can be smoothly touched. It effectively suppresses the adhesion of the evaporant to the surface of the structure. On the other hand, even if it is a gas-conical cylinder having a substantially cylindrical shape upper furnace structure, the flow rate of the inert gas flowing out from between the outer wall of the upper furnace structure and the inner wall of the crucible is adjusted to 6.5. Above cm/sec, the adhesion of the evaporating substance evaporated from the raw material melt can be effectively suppressed. In addition, in order to keep the surface of the raw material melt warm, to suppress the temperature fluctuation of the melt near the crystal growth interface, the single crystal growth can be smoothly carried out, and the 9 I paper scale is applicable to the Chinese National Standard (CNS) A4 specification (210 X 297 mm). ) " (Please read the notes on the back and fill out this page) --------Book --------- Line

1289614 A7 _ B7 _____ V. INSTRUCTION DESCRIPTION (S) As a gas rectifying cylinder, it is possible to use a heat-shielding ring integrated with the lower side of the molten material surface. Although such an upper furnace structure tends to be further lowered in temperature, the adhesion of the evaporant can be effectively suppressed by the method of the present invention. At this time, the flow rate of the inert gas flowing into the inside of the growth furnace body between the outer peripheral surface of the heat shield ring and the inner wall of the crucible is adjusted to 6.5 cm/sec or more. In addition, in the single crystal production using the CZ method, the single-crystal growth is carried out by placing the in-furnace structure above the raw material melt in a complex shape, as long as it flows in the upper furnace. The above effect can be obtained by adjusting the flow rate of the inert gas between the structure and the inner wall of the crucible containing the raw material melt to 6.5 cm/sec to flow into the growth furnace. Next, in the method of the present invention, it is desirable to grow the single crystal by maintaining the internal pressure reduction of the growth furnace at 200 hPa or less. Thereby, the operation of the lower pressure is reduced, and the evaporation of the evaporating material from the raw material melt on the surface of the furnace wall or the upper furnace structure can be reduced. Moreover, the amount of inert gas flowing into the interior of the furnace can be reduced to be economical. Further, it is desirable that the pressure of the growth furnace in operation is limited to at least about 50 hPa. This is based on the flow rate at which the desired inert gas can be easily obtained and the reasons set forth below. That is, the oxygen in the SiO evaporated from the surface of the melt is supplied from the oxygen dissolved in the quartz crucible containing the raw material molten solution. Therefore, the amount of SiO evaporated from the surface of the melt increases as the pressure inside the furnace of the raw material melt is kept below a certain level, and as a result, the deterioration of the quartz wall containing the raw material molten solution is caused to occur in advance. It is difficult to continue the operation of time. Therefore, for the 10 paper scales, the Chinese National Standard (CNS) A4 specification (21〇X 297 Μ) is applicable. 阅读Please read the notes on the back and fill in the page.) --------Book --- ------line

1289614 A7 __-_B7___ V. INSTRUCTIONS (?) To avoid such a situation, it is desirable to maintain a single crystal growth by maintaining a pressure of about 50 hPa in the furnace. Further, after a long period of operation, the evaporate from the molten liquid is often accumulated in the bottom of the growth furnace in which the heat insulating material, the heater, the heater electrode, or the like is disposed. Therefore, in order to suppress such accumulation as much as possible, it is preferable to provide an exhaust port on the bottom surface of the growth furnace of the manufacturing apparatus. For example, in the case of a growth furnace in which the recovery space forming portion (the recovery space for forming a semiconductor single crystal) is integrated in the upper portion of the growth furnace body, the gas rectifying cylinder is allowed to pass from the lower end side of the recovery space. The inside of the growth furnace body is provided in such a manner that the inert gas is introduced into the recovery space, and is discharged to the outside of the growth furnace through an exhaust pipe connected to the bottom surface portion of the growth furnace body. The use of this method makes it possible to smoothly flow the gas inside the furnace, and it is effective to increase the flow rate of the inert gas to 6.5 cm/sec or more. In the single crystal manufacturing apparatus including the exhaust port at the bottom of the growth furnace body and the upper furnace structure, the inert gas introduced from above the growth furnace body is sent to the raw material molten liquid, for example, through a gas rectifying cylinder. The surface moves from the outer periphery to the lower part of the growth furnace, and a part passes through the periphery of the upper furnace structure to the ceiling of the growth furnace body and then moves to the lower part of the growth furnace. Then, it is discharged from the outside of the furnace through the exhaust port. . At this time, if there is only one position of the gas exhaust port, the flow of the gas flowing back into the growth furnace may be irregularly caused to cause the flow rate of the inert gas to be slow, or the portion where the inert gas is not sufficiently refluxed. Easily attached to evaporates. 11 This paper size applies to the Chinese National Standard (CNS) A4 specification (210 x 297 mm) (·Please read the notes on the back and fill out this page) --------Book------- --line

1289614 A7 ___ B7 ___ V. INSTRUCTIONS (/Ο In order to prevent the above-mentioned unfavorable situation, the bottom portion of the growth furnace body is inerted by a gas discharge port provided at a plurality of places around the single crystal pull-up shaft. In addition, the apparatus for manufacturing a semiconductor single crystal according to the present invention is characterized in that a crucible containing a raw material melt is disposed inside the growth furnace, and an upper portion is disposed around the grown single crystal. In the furnace structure, in order to grow the monocrystalline crystal by the Czochralski method, the inert gas is allowed to flow from the upper side toward the molten material surface in the crucible in the structure of the upper furnace, and further used for The exhaust port through which the inert gas is discharged is formed in a plurality of substantially equal angular intervals on a circumferential path centering on the single crystal upper pull axis in the bottom surface portion of the growth furnace. That is, according to the semiconductor single crystal manufacturing of the present invention described above. The apparatus "inert gas flowing in the growth furnace can be recirculated without being retained, and then discharged outside the growth furnace, so that the present invention can be The effect of the crystal growth method is more certain. Further, since the inert gas flowing in the growth furnace can be smoothly discharged to the outside of the growth furnace without being retained in the growth furnace, the molten liquid from the raw material can be suppressed. The oxide of SiO or the like which is evaporated is deposited in the low temperature portion of the growth furnace, so that the inside of the growth furnace can be kept in a clean state for a long time. Therefore, it is difficult to deposit precipitates in the upper portion of the furnace, and the precipitate can be reduced to the raw material during the operation. The molten solution adheres to the growing single crystal or the like to cause the slippage difference on the crystal to be poor, and can be prevented from being operated as a factor that hinders the crystal growth itself. At this time, the quality of the crystal is considered. For long-term continuous stability operation, center on the crystal pull-up axis, and apply inert gas to the Chinese National Standard (CNS) A4 specification (210 X 297 public) as much as possible on the 12-sheet scale. Please read the notes on the back and fill out this page.) - Order -------- 1289614 a7 ___ B7____ V. Invention Description (〖 / ) It is desirable to have a uniform reflow in the growth furnace. Specifically, it is preferable that the plurality of gas discharge ports are formed at substantially equal angular intervals along the circumferential path centering on the single crystal pull-up axis on the bottom surface portion of the growth furnace body. Further, in order to make the inert gas more uniform It is desirable to reflow inside the growth furnace body to provide at least two exhaust ports on the bottom surface of the furnace to have the same degree of gas exhaust capability to constitute a manufacturing device. In particular, the volume inside the growth furnace is large. The large-scale single crystal manufacturing apparatus can function more effectively. 'The single crystal manufacturing apparatus is formed in such a structure, and the inert gas which flows out from the structure of the upper furnace and the inner wall of the crucible containing the raw material molten liquid can be made. The gap is kept uniform throughout the gap, whereby the inert gas flowing over the molten liquid in the growth furnace body is not retained and can be uniformly recirculated, thereby preventing the evaporating material from tending to adhere to the furnace wall of the growth furnace or the upper furnace structure. [Brief Description of the Drawings] Fig. 1 is a schematic longitudinal cross-sectional view showing an example of a single crystal manufacturing apparatus of the present invention. Fig. 2 is a schematic view showing a modification of the heat shielding ring at the lower end of the gas rectifying cylinder into a heat reflecting plate in the single crystal manufacturing apparatus of Fig. 1. Fig. 3 is shown in the single crystal manufacturing apparatus of Fig. 1. Fig. 4 is a cross-sectional view of the vicinity of the bottom of the growth furnace body of Fig. 1 in place of the gas rectification cylinder instead of the inverted conical heat shield. Fig. 5 is a schematic view showing a cross section and a partial longitudinal section of a modified example in which the exhausting projections are formed in various modified versions, and the exhausting ports and the exhausting pipes shown in Fig. 6 are formed in three equal intervals. . 13 This paper size applies to China National Standard (CNS) A4 specification (210 X 297 mm) (please read the notes on the back and fill out this page) --------Book -------- -Line 1289614 A7 ___B7___ V. DESCRIPTION OF THE INVENTION (A) Fig. 7 is a cross-sectional view showing a modification of the shape of the exhaust port. Fig. 8 is a cross-sectional view showing another modification of the shape of the exhaust port. [Best Mode for Carrying Out the Invention] Hereinafter, an embodiment of the present invention will be described with reference to the drawings and an example of the growth of a single crystal of a semiconductor produced by the CZ method. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic cross-sectional view showing an embodiment of a semiconductor single crystal crystal manufacturing apparatus obtained by the CZ method of the present invention. The semiconductor single crystal production apparatus (hereinafter also referred to simply as a single crystal production apparatus) 1 contains a crucible 12 containing a raw material melt (矽 melt) 14 and a growth furnace having a growth furnace body 2 (for growth) The single crystal 23) and the recovery space forming portion 4 (formed integrally above the growth furnace body 2 for accommodating the single crystal 23 which is pulled up from the crucible melt 14). At approximately the center of the inside of the growth furnace body 2, the crucible 12 is placed through the crucible support shaft 13 (the inside is a quartz crucible 12a, and the outer side is a graphite crucible 12b). The crucible 12 is rotatably and vertically movable by the growth mechanism and the operation flow of the single crystal 23 by the crucible drive mechanism 19 attached to the lower end of the support shaft 13. Above the crucible 14 contained in the crucible 12, the gas rectifying cylinder 5, which is the structure of the upper furnace, has a lower end surface directly positioned directly above the crucible melt 14, and surrounds the single crystal 23 which is pulled up. The way to configure. Further, in the present embodiment, the heat shield ring 3 is attached to the lower end portion of the gas rectifying cylinder 5 so as to face the molten liquid surface 14a. The heat shielding ring 30 is formed by a heat insulating layer composed of a porous or fibrous insulating material, which can effectively shield the radiant heat from the bismuth melt 14 and improve the use of the Chinese national standard for the melt __ 14 paper scale. Specifications (210 x 297 public) - (Please read the notes on the back and fill out this page) -------- order --------- line

A7 1289614 ___B7_____ V. Description of the invention (I;) The effect of heat preservation to reduce the temperature variation of the melt 14. In particular, if the heat insulating layer is made of a material having a high heat insulating effect such as a fibrous heat insulating material made of carbon fiber, a better heat insulating effect can be obtained, and a more stable crystal growth can be performed. Further, for the purpose of reducing the influence of the carbonaceous contaminants from the heat insulating layer on the molten liquid, a coating layer made of graphite or the like may be coated around the heat insulating layer. Next, in the furnace body 2 and the gas rectifying cylinder 5 belonging to the upper furnace structure, in-furnace observation window portions 44 and 8 each made of quartz glass are formed. The state of the inside of the gas rectifying cylinder 5 can be detected by the photographing mechanism of the camera 6 or the like through the in-furnace observation window portions 44, 8, and the observation is continued, and the growth of the sand single crystal is performed. Here, as shown in Fig. 2, instead of the heat shield ring 30, a plate-shaped heat reflection ring 130 (for example, an isotropic graphite) having an outer diameter on an inverted truncated cone may be provided. Further, Fig. 3 shows an example in which a heat shielding curtain 55 made of graphite having a truncated cone-shaped outer shape having a narrow lower end portion is provided as an upper furnace structure. At this time, a pin-shaped heat reflecting plate 55a (here, substantially parallel to the molten liquid surface) is provided in a form in which the lower end portion can be protruded in the past. 2 and FIG. 3, the same reference numerals are given to the same components as those in FIG. 1, and detailed description thereof will be omitted. Referring back to Fig. 1, on the outer side of the crucible 12, a heater 15 for melting the polycrystalline raw material added to the crucible 12 and holding the crucible melt 14 at a predetermined temperature is a heater electrode portion not shown. The support is placed upright on the bottom surface of the growth furnace body 2. When the single crystal grows, electric power is supplied to the heater 15 by the heater electrode portion to generate heat to the heater 15, and the crucible melt 14 is maintained at a high temperature. The 15 t-segment scale applies to the Chinese National Standard (CNS) A4 specification (210 X 297 mm) ' (Please read the note on the back and fill out this page) -------- Order---- 1289614 A7 ___B7___ V. OBJECTS OF THE INVENTION In the collection space forming unit 4, a gas introduction port 9a for introducing an inert gas such as Ar gas into a growth furnace is provided, and flows through the inert gas connected to the gas introduction port 9a during operation. The inert gas ' of the gas pipe 9 is subjected to flow rate adjustment by the gas flow rate control device 12 on the inert gas pipe 9, and is introduced into the inside of the growth furnace. On the other hand, in the inside of the growth furnace main body 2, in order to effectively heat the inside of the growth furnace main body 2 and protect the furnace wall, a heat insulating material 16 and a lower heat insulating material 3 are provided. Further, a gas discharge port 11 for discharging the inert gas introduced into the growth furnace is provided on the bottom surface portion of the growth furnace body 2, and the inert gas in the growth furnace is discharged through the exhaust pipe 7 through the gas discharge port 11 Go outside the growth furnace. Further, the exhaust pipe 7 is collected on the collecting pipe 17, and a conduction valve 18 is provided in the middle of the collecting pipe 17, and a vacuum pump for assisting the exhaust gas from the inert gas of the growing furnace is provided in front of the conducting valve 18. Not shown in the figure), the inside of the growth furnace is maintained in a reduced pressure state. Further, the pressure inside the growth furnace is regulated by the conduction valve 18 provided in the exhaust pipe and maintained at a furnace internal pressure (e.g., 50 to 200 hPa) suitable for crystal growth. Further, each of the exhaust pipes 7 has substantially the same axial cross-sectional area and length, and is collectively evacuated by the above-described vacuum pump via the collecting pipe 17. Thereby, the inert gas is discharged from the respective gas discharge ports 11 at equal flow rates. In the present embodiment, in order to efficiently and uniformly discharge the inert gas in the growth furnace body 2 from the growth furnace, as shown in Fig. 4, the gas discharge port 11 (and the corresponding exhaust pipe 7) are grown. The center of the growth furnace at the bottom of the furnace body 2, that is, two positions symmetric with respect to the single crystal pull-up axis (that is, the angle of formation around the single crystal pull-up shaft is about 16). National Standard (CNS) A4 Specification (210 X 297 mm) (Please read the notes on the back and fill out this page) --------Book --------- Line 1289614 A7 ____B7__ Five , invention description (K) 180 °). Further, as shown in Fig. 6, the gas discharge port 11 (and the corresponding exhaust pipe 7) may be formed at three or more places with respect to the single crystal pull-up shaft at substantially equal angular intervals. Thereby, a more uniform reflux of the inert gas can be performed. Further, in the present embodiment, in order to prevent the bismuth melt 14 from leaking out of the crucible 12 and reaching the lower portion of the growth furnace main body 2 for any reason, the high temperature enthalpy melt 14 flows directly from the gas discharge port 11 to the growth. The situation outside the furnace was the following design. In other words, on the bottom surface of the growth furnace body (growth furnace) 2, the communication protruding portion 7a and the exhaust pipe 7 are formed in a corresponding manner from the bottom surface, and the exhaust port 11 is protruded relative to the exhaust gas. The portion 7a has a lower edge position which is separated from the bottom surface by a predetermined height Η and is formed in a spaced relationship. Further, as shown in Fig. 5 (b), the exhaust port 61 may be provided to open the upper end surface in the case of the exhaust protruding portion 7a. However, in the present embodiment, the exhaust protruding portion 7a has The front end portion is sealed with the front end sealing portion 7c, and the exhaust port 11 is opened on the side surface of the exhaust protruding portion 7a. Thereby, it is possible to effectively prevent the fly or the like of the melt 14 from falling from directly entering the inside of the exhaust pipe 7. As shown in Fig. 5 (a), the exhaust port 11 is formed in plural at a predetermined interval in the circumferential direction of the outer peripheral surface of the exhausting projection portion 7a. Further, in the present embodiment, the upper end portion of the exhaust pipe 7 penetrates the bottom portion of the growth furnace body 2 from the bottom surface by a predetermined length η to form the exhaust projection portion 7a. Thereby, since the exhaust projecting portion 7a is simultaneously formed by the pipe member forming the exhaust pipe 7, the number of parts can be reduced. However, as shown in Fig. 5(c), it is also possible to form a cylindrical shape on the outer side of the exhaust pipe 7. This paper scale applies the Chinese National Standard (CNS) A4 specification (2K) X 297 mm) (please first Read the notes on the back and fill out this page) --------Book --------- Line

1289614 A7 --------B7____ V. The structure of the exhausting projection portion 67 of the invention (K). In Fig. 5(c), the upper side of the exhausting projection portion 67 is open to form an exhaust port 69, and above it, a shielding plate 68 serving as a front end sealing portion is provided at a predetermined interval. The shield plate 68 is coupled to the upper end surface of the annular portion of the exhausting projection portion 67 through a plurality of pillar portions 69 which are arranged at a predetermined interval in the circumferential direction. In addition, in either case, the position where the exhaust port 11 is formed does not allow the sand melt 14 to flow out therefrom (even if the melt 14 can be stored in the growth furnace after being stored in the crucible 12), Become a device with higher reliability. Specifically, for example, in FIG. 1, it is assumed that the height reaching the lower edge of the exhaust port U is Η, and when the liquid reaches the height Η, the volume of the allowable liquid in the growth furnace is V(H), and the 坩埚12 is When the content is integrated into VC, it is only necessary to determine the V(H)^VC. Next, above the recovery space forming portion 4, a non-illustrated one is used to pull up the single crystal 23 from the crucible melt 14 to wind the metal wire 22, or to rotate the crystal when the single crystal grows. The wire is wound up and rolled out. Further, a seed holder 20 is attached to the front end of the metal wire 22 wound by the wire winding and unwinding mechanism, and the seed crystal holder 20 locks the seed crystal 21. Hereinafter, an example of a method for producing a single crystal of the above single crystal production apparatus 1 will be described. First, the quartz crucible 12b provided in the single crystal production apparatus i is filled with a polycrystalline germanium material, and the heater 15 is heated to be melted to become the crucible melt 14. Then, after the molten metal 14 is settled at a predetermined temperature, the wire winding and unwinding mechanism is operated to wind up the metal wire, so that the front end of the seed crystal 21 stuck to the seed crystal holder 20 is smoothly 18 I. The scale applies to the China National Standard (CNS) A4 specification (210 X 297 mm) (please read the notes on the back and fill out this page) _ --------Book------- --Line · A7 1289614 ___B7____ V. INSTRUCTION DESCRIPTION (Q) Contact with the surface of the crucible melt 14. Thereafter, the crucible 12 and the seed crystal 21 are rotated in opposite directions while the metal wire 22 is wound and pulled up to grow the monocrystalline crystal 23 below the seed crystal 21. When the monocrystalline crystal 23 is grown, the inert gas system that has flowed into the recovery space forming portion 4 from the gas introduction port 9a flows from the recovery space forming portion 4 to the gas rectifying cylinder 5 which is the upper furnace structure, and then flows. It is on the raw material melt surface 14a. Then, along the raw material melt surface 14a, it is folded back over the lower edge of the gas rectifying cylinder 5, and passes through the gap between the heat shielding ring 30 and the inner wall of the crucible 12, and then flows into the growth furnace body 2. Specifically, by controlling the amount of inert gas flowing into the growth furnace body 2 and the pressure in the furnace, the gap D between the heat shield ring 30 disposed directly above the crucible melt 14 and the inner wall of the crucible 12 is controlled. The flow rate of the inert gas is adjusted to 6.5 cm/SeC or more (here, the size of the gap D in the radial direction with respect to the single crystal pull-up axis is substantially constant in the circumferential direction). Further, a part of the inert gas system is directly sent to the vicinity of the gas rectifying cylinder 5 to reach the vicinity of the ceiling of the growth furnace body 2. Then, it flows downward from the upper side of the growth furnace main body 2 to the exhaust port 11, and flows back into the growth furnace main body 2. Finally, each exhaust port 11 provided on the bottom surface of the growth furnace main body 2 is exhausted in a substantially uniform manner. The tube 7 and the collection pipe are discharged to the outside of the growth furnace. Thereby, it is possible to effectively suppress the evaporation of SiO or the like from the crucible melt 14 to the ceiling wall of the recovery space forming portion 4 and the outer surface of the gas rectifying cylinder 5. In particular, by preventing the evaporating substance from adhering to the inside of the furnace viewing glass 8 of the gas rectifying cylinder 5, it is possible to prevent the observation window glass 8 from being obscured in the furnace and to be incapable of observing the poor growth of the single crystal growth portion. 19 This paper size applies to China National Standard (CNS) A4 specification (210 X 297 public). (Please read the note on the back and fill out this page) -1 ϋ nnnn^tfJ* IIII MM MM _ 丨«i A7 1289614 ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ A shape extending in a circumferential path centered on a single crystal pull-up axis. As an example, as shown in Fig. 7, the shape of the exhaust port may be an arc shape along a circumferential path. By designing such a shape, it is possible to carry out the reflux of the inert gas in the growth furnace more uniformly without any irregularity. Further, the exhaust port may be formed in plural numbers on the bottom surface portion of the growth furnace along a plurality of circumferential paths which are set at positions different in the radial direction around the single crystal pull-up axis. In Fig. 8, an exhaust pipe 7 having an exhaust port shape as shown in Fig. 7 is formed in two rows along two circumferential paths defined by concentric circles. Thereby, the inert gas can be refluxed more uniformly. Further, the present invention is not limited to the growth use of the above-described monocrystalline single crystal. For example, the method for producing a single crystal of the present invention and the semiconductor single crystal production apparatus can also be used as a method for growing a single crystal by using the MCZ method (that is, growing a single crystal while applying a magnetic field to a raw material melt) and a manufacturing apparatus. Further, the present invention is also applicable to the case where another semiconductor single crystal such as a compound semiconductor is grown by the CZ method. (Embodiment) The present invention will be more specifically described by the following examples, but the invention is not limited thereto. (Example 1) A single crystal production apparatus having the same configuration as that of Fig. 1 was used, except that the group of the exhaust pipe 7 and the exhaust port 11 located on the bottom surface of the growth furnace was set to one set, and the growth of the single crystal was performed. Moreover, the diameter of the heat shielding ring 30 is 20. The paper size is applicable to the Chinese National Standard (CNS) A4 specification (210 X 297 mm) ---II---订--------- (·Please Read the notes on the back and fill out this page)

A7 !289614 —-----B7_ V. Description of invention (/?) 400mm. Further, a crucible 12b made of quartz having a diameter of 440 mm and a polycrystalline silicon material of 60 kg were filled, and after the inside of the growing furnace was filled with Ar gas, the heater 15 was heated to generate the crucible melt 14 of the raw material melt. Thereafter, after the temperature of the molten metal 14 to be stabilized at a temperature suitable for the growth of the single crystal, the seed crystal 21 is attached to the surface of the crucible melt 14, and is slowly pulled up to the melting while rotating in the opposite direction of the crucible 12. Above the liquid, a single crystal having a diameter of 150 mm is grown below the seed crystal. Further, in order to discharge the evaporate from the crucible melt 14 to the outside of the growth furnace, Ar gas was refluxed at 100 liters/min. The interval D between the outer circumference of the heat shield ring 30 and the inner wall of the crucible is 20 mm, and the flow rate of the inert gas flowing through the interval D is estimated to be 6.5 cm/sec. Also, the pressure in the furnace was 100 hPa. At this time, the internal condition was observed from the outside of the growth furnace, and it was found that there was no contaminant or ambiguity in the observation window portion 8 in the furnace of the gas rectifying cylinder 5, and the error of the diameter of the single crystal 23 which was pulled up was also at the target. Since the crucible is about ±1 mm, the crucible melt 14 is not solidified, but the crucible 12 is further filled with the polycrystalline crucible raw material, and the single crystal is grown again. At this time, the amount of the raw material melt was also 60 kg, whereby the crucible melt 14 also grew into a single crystal 23 having a diameter of 150 mm. This operation is repeated until the end of the growth of the single crystal of the third root. It is confirmed that the inside of the growth furnace is blurred, and the observation window portion 8 in the furnace is blurred, and the oxide of the crucible is attached to the lower portion of the gas rectifying cylinder 5, It is judged that it is difficult to continue the manufacture of single crystals. Then, the power of the heater 15 is turned off to cool the inside of the furnace, and the operation is terminated. At this time, the time for the growth of the single crystal of the third root is 8 hours after the start of the operation. Also 'confirm the final 21 paper scales applicable to China National Standard (CNS) A4 specifications (21〇X 297 mm) (please read the notes on the back and fill out this page) --------- -------- Line · A7 1289614 ____B7___ V. Inventive Note (/) The diameter of the single crystal 23 grown is found to be large in the vicinity of the observation window 8 in the furnace. A deviation of a diameter of ±2 mm was observed with respect to the target enthalpy in the second half of the crystallization 23. In addition, when the temperature is lowered to the normal temperature and the adhesion state of the oxide inside the growth furnace is confirmed, it is found that the vicinity of the ceiling of the growth furnace body 2 and the outer surface of the gas rectifying cylinder 5 are more or less in terms of the formation side of the exhaust port 11. Attachments of SiO or the like were observed. Further, at the inner side away from the exhaust port 11, more deposits are visible in the upper portion of the gas rectifying cylinder 5 and near the ceiling of the growth furnace body 2. (Second Embodiment) Next, as shown in Fig. 1, a single crystal production apparatus in which the group of the exhaust pipe 7 and the exhaust port 11 is set to two is used, and the other conditions are the same as in the first embodiment. The growth of crystallization. As a result, in the same manner as in the first embodiment, when the single crystal of the third strip was pulled up, it was found that the observation window portion 8 in the furnace was falsified, and it was difficult to continue the operation, and the single crystal was pulled up. Then, after the temperature was sufficiently lowered, the inside of the furnace was observed in the same manner as in the first embodiment, and it was found that the deposits on the outer surface of the ceiling portion of the growth furnace main body 2 and the gas rectifying cylinder 5 were less suppressed, and the adhesion state was also improved. Uniform. This means that the inert gas is not retained and is refluxed in the furnace, and the evaporate from the raw material melt can be smoothly discharged to the outside of the furnace. (Example 3) Growth of a single crystal was carried out using the single crystal production apparatus shown in Fig. 1. Further, the same conditions as in the second embodiment were employed except that the diameter of the heat shielding ring 30 disposed at the lower end of the gas rectifying cylinder 5 was slightly larger than 410 mm. At this time, the distance D between the outer circumference of the heat shield ring 30 and the inner wall of the crucible is 15 mm, 22 (please read the back note before filling in the page) • -------- Order ------- -- t This paper scale applies to China National Standard (CNS) A4 specification (210 X 297 dong) 1289614 A7 _B7____ V. Description of invention (W) The flow rate of inert gas flowing through gap D is estimated to be about 8 cm/Sec. Also, the pressure in the furnace was 100 hPa. In this way, even if the growth of the single crystal of the fourth strip is completed, no obscuration is observed in the observation window portion 8 in the furnace, and a considerable degree of attachment due to the deposit is not observed on the surface of the gas rectifying cylinder 5. Pollution. On the other hand, since the operation time has exceeded 1 hour at this time, it is judged that the durability limit of 坩埚12 is approached, and the growth of single crystal is ended. After that, the diameter of the single crystal of the fourth strip was confirmed, and it was found that there was no significant fluctuation in the crystal diameter, and the diameter error with respect to the target crucible was controlled to about ±1 mm, and it was found that the operation time exceeded 100 hours in this example. The detection function of the detection device can still be fully ensured. (Comparative Example) The growth of the single crystal was carried out using the single crystal production apparatus 1 shown in Fig. 1 . Further, the same conditions as in the second embodiment were employed except that the diameter of the heat shield ring 30 disposed at the lower end of the gas rectifying cylinder 5 was set to be 390 mm smaller than that of the first embodiment or the second embodiment. At this time, the interval between the outer circumference of the heat shield ring 30 and the inner wall of the crucible is 25 mm', and the flow rate of the inert gas flowing through the gap is estimated to be about 5 cm/sec. Also, the pressure in the furnace was 100 hPa. Then, when one single crystal was pulled up and the inside of the growth furnace was observed, it was found that the diameter of the crystal of the pulled up was also 1 mm with respect to the target 由于 because the observation window portion 8 in the furnace was not contaminated or blurred. Therefore, the ruthenium melt 14 is not solidified but the polycrystalline ruthenium raw material is further charged, and the ruthenium single crystal is pulled up again. In the pull-up of the single crystal after the second strip, the raw material melt is returned to 60 kg in the same manner as the first one. Thus, the raw material melt grows into a single crystal having a diameter of 150 mm as in the first strip. 23 The paper size applies to the Chinese National Standard (CNS) A4 specification (210 X 297 mm) (please read the notes on the back and fill out this page) - -ϋ 1 i·— n ϋ n ϋ_Β- 雠ϋ ϋ · ϋ ·ϋ II ϋ I i^in ϋ I 1 ϋ ·ϋ ·ϋ ϋ ϋ ^1 ϋ n I nn ϋ ϋ nt 1289614 A7 -----B7_______ V. Description of invention (A) However, in Article 2 When the growth of the single crystal is completed, the blurring of the observation window portion 8 in the furnace is observed when the polycrystalline germanium raw material is melted in order to grow the single crystal of the third crystal, and the blurring is not performed at the stage of allowing the seed crystal 21 to adhere to the crucible melt 14. Further, it is more difficult to confirm that it is difficult to see the ring as seen at the boundary between the grown single crystal 23 and the tantalum melt 14, and the operation is terminated at this time. The manufacturing time at this time is calculated to be more than 50 hours from the start of the operation. After that, the state of the inside of the growth furnace is observed, and a large amount of deposits of oxides or the like are deposited on the outer surface of the gas rectifying cylinder 5 and above the growth furnace main body 2, and the entire outer surface of the gas rectifying cylinder 5 is covered with the deposit. . Further, the adhesion of the oxide was observed remarkably in a portion of the observation window portion 8 in the furnace. [Description of Symbols] 1 Single crystal manufacturing apparatus 2 Growth furnace main body 3 Lower heat insulating material 4 Recovery space forming unit 5 Gas rectifying cylinder 6 Camera 7 Exhaust pipe 7a, 67 Exhaust protruding portion 7c Front end sealing portion 8, 44 In-furnace observation Window part 9 Inert gas tube 9a Gas inlet (Please read the back of the note first and then fill in this page) Τ

Nn _I ϋ ·ϋ ϋ ϋ ϋ n ϋ I nn in ϋ n ϋ ϋ ϋ emmt I ϋ i I «1· II ·ϋ ϋ ϋ —ϋ ϋ II A paper scale applies to the Chinese National Standard (CNS) A4 specification (21〇χ 297 公公) 1289614 V. Description of invention (W) A7 11,61 Exhaust port 12 坩埚13 坩埚Support shaft 14 矽Fluid 15 Heater 16 Insulation material 17 Collecting pipe 18 Conducting valve 19 坩埚Drive mechanism 20 Seed crystal holder 21 seed crystal 22 metal wire 23 矽 single crystal 30 heat shielding ring 55 heat shielding curtain 55a heat reflecting plate 68 shielding plate 69 pillar portion 130 heat reflecting plate Γ Please read the back note before filling in this page)

--Order --------- Line II t This paper scale applies to China National Standard (CNS) A4 specification (210 X 297 mm)

Claims (1)

A8 B8 : 96 side January soup E) H] 霣 scale _»-β»__ ··«·- C8 D8 '6. Application No.】 Fan Yuan Application No. 90123730! 1. A method for producing a single crystal, characterized in that inside the growth furnace, a crucible containing a crucible melt is placed and surrounded The grown single crystal is provided in the upper furnace structure, in which the inert gas flows from the upper side toward the molten liquid surface in the crucible in the upper furnace structure, and by the Czochralski Method (Czochralski Method) And growing the sand monocrystal, and in the growth of the single crystal, the inert gas flowing out from the opening at the front end of the upper furnace structure is installed in the gas rectifying cylinder (located in the foregoing crucible melt) The lower end portion is disposed around the outer layer of the upper inner furnace structure and the space surrounded by the inner wall of the crucible is discharged to the growth furnace. In addition, the flow rate of the inert gas when passing through the space is adjusted to be 6.5 cm/sec or more and 20 cm/sec or less. 2. The method for producing a single crystal according to the first aspect of the patent application, wherein the upper furnace is passed through the furnace observation window formed by the growth furnace and the upper furnace structure outside the growth furnace. The state of the inside of the structure is optically detected or observed to grow the monocrystal. 3. The method for producing a single crystal according to the first aspect of the patent application, wherein the upper furnace structure is a gas rectifier. 4. The method for producing a single crystal according to the third aspect of the patent application, wherein the gas rectifying cylinder is formed by integrating the heat shielding ring on a side opposite to the surface of the crucible melt. 5. The method for manufacturing a single crystal according to any one of the first to fourth patent applications is to reduce the internal pressure of the growth furnace to a pressure of 200 hPa or less. The paper is applicable to the Chinese National Standard (CNS) A4 specification. (210 X 297 mm) A8B8C8D8 1289614. Sixth, apply for the patent park state to carry out the growth of the aforementioned single crystal. 6. The method for producing a single crystal according to any one of claims 1 to 4, wherein the growth furnace is formed in a top portion of the growth furnace body to form a recovery space forming portion (for forming the aforementioned single crystal) In the integration space, the gas rectifying cylinder is provided in a form extending from the lower end side of the recovery space to the inside of the growth furnace, and the inert gas is introduced into the recovery space and connected to the growth furnace. The exhaust pipe on the bottom surface of the main body is discharged to the outside of the furnace. 7. The method for producing a single crystal according to the sixth aspect of the patent application is the bottom portion of the growth furnace body, wherein the inert gas is discharged from a gas exhaust port provided at a plurality of places around the single crystal pulling shaft. 8. The method for producing a single crystal according to the seventh aspect of the invention, wherein the plurality of gas discharge ports are on a bottom surface of the growth furnace body and are substantially in a circumferential path centered on the single crystal pullup axis. The formation of equal angular intervals. Use Chinese National Standard (CNS) A4 specification (210 X 297 mm)