WO2010146853A1 - Silicon monocrystal and production method for same - Google Patents
Silicon monocrystal and production method for same Download PDFInfo
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- WO2010146853A1 WO2010146853A1 PCT/JP2010/004012 JP2010004012W WO2010146853A1 WO 2010146853 A1 WO2010146853 A1 WO 2010146853A1 JP 2010004012 W JP2010004012 W JP 2010004012W WO 2010146853 A1 WO2010146853 A1 WO 2010146853A1
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- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B15/00—Single-crystal growth by pulling from a melt, e.g. Czochralski method
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- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
- C30B29/02—Elements
- C30B29/06—Silicon
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- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B15/00—Single-crystal growth by pulling from a melt, e.g. Czochralski method
- C30B15/20—Controlling or regulating
- C30B15/22—Stabilisation or shape controlling of the molten zone near the pulled crystal; Controlling the section of the crystal
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
Definitions
- the present invention relates to a technique suitable for use in a method and apparatus for producing a silicon single crystal.
- This application claims priority based on Japanese Patent Application No. 2009-145248 filed in Japan on June 18, 2009, and Japanese Patent Application No. 2009-14695 filed on June 19, 2009 in Japan. And the contents thereof are incorporated herein.
- CZ method As a method for producing a silicon single crystal that is a material of a silicon wafer, a growing method by the Czochralski method (hereinafter, CZ method) is known.
- a method called CZ method is used for manufacturing a silicon single crystal.
- a vacuum inert gas (Ar) gas atmosphere raw material polycrystalline silicon housed in a quartz crucible is melted by a heating means such as a resistance heater.
- a seed crystal (seed) is immersed in the surface of the silicon melt that is near the melting point after melting (seed melt contact process), and the liquid temperature is adjusted to such an extent that the seed crystal is compatible with the silicon melt.
- seed drawing with a diameter of about 5 mm is performed while pulling the seed upward (neck process).
- the crystal diameter is expanded in a conical shape while adjusting the liquid temperature and the pulling speed so as to obtain the product diameter (shoulder process).
- the product part is grown to a certain length in the vertical direction (straight barrel process), and then the crystal diameter is reduced to a conical shape (tail process). Cut off from the melt and finish.
- the neck portion in the seed squeezing (necking) process, in which the silicon seed crystal is brought into contact with the raw material silicon melt, the neck portion once reduced to about 4 mm in diameter is about 50 to 200 mm in length. Form. Thereafter, a technique of thickening the single crystal by the shoulder portion until a predetermined diameter is obtained can be employed. As a result, dislocations propagated from slip dislocations introduced into the seed crystal can be eliminated in the neck portion, and a dislocation-free silicon single crystal can be pulled up.
- Patent Documents 1 to 3 there is a method in which a large diameter portion having an enlarged diameter is created in front of the shoulder shape, and the crystal is held by gripping the large diameter portion.
- Patent Document 4 describes a method for demonstrating the dislocation-freeness by growing only the neck portion in the necking step.
- Patent Documents 1 to 3 have a problem that complete dislocation-freeness cannot be realized.
- the neck diameter is reduced to, for example, about 4 mm and grown to a length of about 500 mm, which is conventionally considered to be sufficient for dislocation, the dislocation may remain up to the straight body portion.
- Patent Document 4 when the inside of the furnace is broken to take out the neck, contamination due to contaminants from the outside of the furnace or heavy metal contaminants from the moving part of the manufacturing apparatus occurs, resulting in a quartz crucible. It is difficult to reuse the raw material remaining inside. At present, when the diameter of the wafer is increased, it is impossible to waste a large amount of silicon raw material, so that it cannot be applied to actual manufacturing, and a method to replace it has been demanded. Further, when a movable part as described in Patent Document 5 is provided in the furnace, the movable part becomes a contamination source, and as a result, there is a problem that it cannot be used for pulling a silicon single crystal.
- dislocation generation and removal is not accurately understood. Therefore, it has not been understood how dislocations can be completely removed.
- dislocations axial dislocations
- these axial dislocations exist over the entire length of the straight body, and it was unclear how they could be removed.
- the present invention has been made in view of the above circumstances, and achieves the following objects. 1. Dislocations generated in the seed melt contact process are surely removed to achieve dislocation-free. 2. Accurately capture the state of occurrence and removal of dislocations, especially axial dislocations. 3. To accurately grasp the relationship between dislocation behavior at the neck and the lifting conditions. 4). Accurately determine lifting conditions that can eliminate dislocations.
- the inventors of the present application have studied to grow safely by increasing the diameter of the portion conventionally referred to as the neck portion while maintaining the dislocation-free state.
- a heavy silicon single crystal having an order of several hundred kilograms to several t is manufactured by a simple method without placing a special device as a contamination source in the furnace.
- the above-described normal dash neck method is used.
- the diameter is reduced during the growth of a silicon single crystal, and dislocations introduced when the silicon seed crystal comes into contact with the silicon melt (heat shock dislocation, misfit dislocation) are removed.
- heat shock dislocation, misfit dislocation are removed.
- dislocations are more easily removed when the diameter of the neck portion is set to be thinner.
- the thickness of the neck part was set to the dimension calculated from these relationships.
- the crystal load could be supported with a diameter of about 5 mm.
- the diameter of the silicon single crystal is 450 mm, when the crystal is grown to a necessary length, there is a possibility that the load cannot be supported by the neck portion.
- the inventors of the present application believe that if such conditions can be clarified, it is possible to grow large-sized silicon crystals by a simple method without the need for special treatments and apparatuses, and the behavior of dislocations inside the neck portion accompanying the pulling is considered. Sought a means to scrutinize.
- the inventors of the present application examined how dislocations behave in the necking process. We also examined why axial dislocations cannot be removed. Then, if the behavior of the dislocation could be clarified, it was thought that it was possible to grow a silicon crystal from which the dislocation was completely removed by a simple method without the need for special treatment or equipment. And we searched for a means to scrutinize the behavior of dislocations inside the neck part with the pulling.
- dislocation state analysis in the neck was performed using X-ray topography.
- the cross section of the neck portion is sliced to a thickness of about 1.5 mm, and then the surface is etched with a mixed acid or the like to observe X-ray transmission. Therefore, since only an image of a certain cross section can be directly observed, the images at intervals of 1.5 mm are connected to capture the state change of dislocation accompanying crystal growth. Therefore, only dislocations propagating obliquely with respect to the pulling axis, which is the central axis in the pulling direction of the silicon single crystal, could be observed.
- Non-Patent Document 1 when white X-rays are used as high-energy radiation at the level described in Non-Patent Document 1, it has been found that dislocations disappear in a loop when the neck portion is observed. It was also found that dislocations exist in addition to the normal ⁇ 111 ⁇ plane. That is, the present inventors have revealed the existence of the above-described axial dislocation for the first time by such a technique. Axial dislocations were observed as pits in the straight body of a silicon single crystal and a sliced wafer. However, it was not recognized that the observed pits were axial dislocations.
- This axial dislocation can be clearly detected from the other pits on the wafer by the following method.
- a silicon single crystal obtained by slicing a wafer has a crystal habit line properly formed and can realize dislocation free, and is recognized as a single crystal by other inspections.
- axial dislocations can be identified by performing strain measurement using an optical inspection means.
- an inspection means a strain inspection apparatus (SIRD; registered trademark) SirTec manufactured by JENAWAVE, which can visually observe the internal stress distribution state, can be used.
- the silicon wafer to be evaluated is subjected to a revealing process by heating at 900 to 1250 ° C. ⁇ 1 sec or more at a temperature rising / falling rate of 10 to 300 ° C./sec. Thereafter, the surface properties of the wafer including the manifested strain are evaluated.
- This manifestation process is intended to generate a large temperature difference in the wafer surface by rapid heating and to generate thermal stress due to this temperature difference. Therefore, a long heating time is not required, and the desired effect can be exhibited even with a short heating time of about 1 sec.
- FIG. 11 shows an observation example of a wafer having a manifested axial dislocation and an observation example of a wafer having no axial dislocation.
- the observation example shown in FIG. 11A is an example in which three axial dislocations have occurred
- the observation example shown in FIG. 11B is an example in which no axial dislocation has occurred.
- the distortion observed at the edge of the wafer is caused by the support of the wafer during the heat treatment.
- Axial dislocation occurs when the seed crystal is brought into contact with the melt.
- Axial dislocations are dislocations that continuously exist in the crystal growth direction up to a necking step, a shoulder portion formation (expansion) step, and a straight body portion growth step.
- Axial dislocations exist only in specific areas of the wafer when the wafer is manufactured.
- axial dislocations are removed depending on a conventionally used technique for growing a neck part, such as a diameter expansion, a diameter reduction, or a neck part length exceeding a certain value as in the dash neck method. I could't.
- the silicon single crystal 60 that has been pulled up has a seed crystal (seed crystal) T, a reduced diameter portion (neck portion) N0 as a silicon single crystal grown across the seeding interface T00, and an expanded diameter.
- heat shock dislocations Jn and misfit dislocations Jm are generated in the reduced diameter portion (neck portion) N0.
- the heat shock dislocation Jn is generated on the seed crystal T side by the heat shock when the seed crystal T is brought into contact with the silicon melt, and is taken over to the neck portion N0 side of the growing silicon single crystal 60.
- the misfit dislocation Jm occurs when there is a mismatch in lattice constant between the seed crystal T and the neck portion N0 of the silicon single crystal 60.
- the axial dislocation J grows in the growth direction (axial direction) among the heat shock dislocation Jn and the misfit dislocation Jm.
- the axial dislocations J are 10 when the notch is in the 12 o'clock direction on the surface. Observed in the hour and 4 o'clock directions. More specifically, assuming that the notch in 100 directions is 0 °, a region in the range of 120 ° to 135 °, and a region in the range of 315 ° to 350 ° symmetrical to the central axis of this region and the silicon single crystal 60. Observed at.
- the regions are observed only in the range of the difficult-to-remove dislocation existence region J1 composed of the regions rotated by 90 ° and 45 ° about the central axis of the silicon single crystal 60. That is, the axial dislocation J extends in the growth direction (center axis direction) of the silicon single crystal 60 in the region J1.
- the region J1 shows only the regions in the range of 120 ° to 135 ° and 315 ° to 350 °.
- the axial dislocations may disappear in a silicon single crystal grown over a predetermined length.
- the manufacturing site recognizes that it is an axial dislocation only after combining the data of a wafer obtained by slicing a single silicon crystal that has been pulled up.
- Axial dislocations usually exist over the entire length of a single silicon single crystal and often penetrate the silicon single crystal.
- white X-ray topography by white X-rays as high-energy radiation light for measuring dislocations in a silicon single crystal pulled by the CZ method.
- X-rays having an energy of about 30 keV to 1 MeV, about 40 keV to 100 keV, and about 50 keV to 60 keV having a continuous spectrum are used.
- X-rays having a wavelength of about 0.001 nm to 0.25 nm are used.
- X-rays having a distribution as shown in FIG. 5 are used in which the number of photons obtained through a 1 mm ⁇ 1 mm slit at a distance of 44 m from the light source.
- FIG. 5A shows the X-ray state as an example of the high-energy radiated light in the present invention, and shows the distribution of the number of photons with respect to the X-ray energy.
- the graph shown in FIG. 5B shows X-rays as an example of high-energy radiation light in the present invention, and shows the distribution of the number of photons with respect to wavelength.
- the beam diameter of the X-ray is preferably 0.01 to 1 times the diameter of the neck portion that is the object to be measured.
- the behavior of dislocations inside single crystal silicon can be observed as a three-dimensional image without performing a destructive inspection such as slicing, and information on the position of the dislocations. It has become possible for the first time to observe the nature of this.
- the CT based on the topographic image is reconstructed. Thereby, the three-dimensional position information of the dislocation line is obtained.
- white X-ray topography as shown in FIG. 6 is performed to determine dislocation properties (such as Burgers vector).
- X-ray topography is also called X-ray diffraction microscopy, and is a method for observing the spatial distribution of defects in a non-destructive manner.
- diffraction spots are observed.
- X-ray topography analyzes this diffraction spot.
- An imaging plate that utilizes the photoluminescent phenomenon of a fluorescent plate, X-ray film, nuclear dry plate, and photostimulable phosphor (BaFBr: Eu 2+ ).
- CCD type X-ray detector using a charge coupled device CCD As the X-ray detector used in the present invention, it is preferable to consider the following characteristics in terms of spatial resolution and dynamic range.
- the pulling conditions include, for example, the pulling speed, the height (distance) from the surface of the silicon melt to the heat shielding member, and the seed crystal before contact with the silicon melt. It is time etc. to hold above. From this, using the means to observe the dislocation behavior inside the silicon single crystal by high energy synchrotron radiation, the neck part (dislocation) when using the manufacturing equipment adopting the structure combining different furnaces and different carbon materials It is possible to determine the manufacturing conditions of the removal section and the dislocation-free section.
- the manufacturing conditions are related to the characteristics of all single crystals and wafers, in addition to the so-called control parameter conditions, and include devices, means, parts, states, and processes for pulling and manufacturing single crystals.
- the inventors of the present application have used a simple method to place a large-scale silicon single crystal on the order of several hundred kilograms to several t without axial dislocations without placing a special device as a contamination source in the furnace. For the purpose of nurturing safely in a non-existent state, we examined increasing the diameter of the part that was previously called the neck part.
- the aforementioned dash neck method is usually used, and the neck portion is formed by reducing the diameter of the silicon single crystal in the initial stage of growth.
- dislocations heat shock dislocations, misfit dislocations
- the neck portion is formed by reducing the diameter of the silicon single crystal in the initial stage of growth.
- dislocations heat shock dislocations, misfit dislocations
- the thickness of the neck portion was calculated from these relationships.
- a crystal having a diameter of about 300 mm can support the load of the crystal with a diameter of about 5 mm.
- the crystal has a diameter of 450 mm, the load may not be supported if the required crystal length is set. Therefore, the inventors of the present application examined increasing the diameter of the neck as described above.
- the inventors of the present application have found that the above-described axial dislocation J may exist when the diameter of the neck portion is increased. Conventionally, such an axial dislocation has not been confirmed.
- the behavior of the heat shock dislocation Jn and the misfit dislocation Jm has the following characteristics.
- the behavior of the heat shock dislocation Jn and the misfit dislocation Jm refers to the propagation direction in the process of growing a silicon single crystal that pulls up the neck portion, the shoulder portion, and the straight body portion.
- dislocations move on the slip plane ( ⁇ 111 ⁇ plane in the case of silicon). 2) Usually, dislocations are introduced at ⁇ 111 ⁇ . 3) In rare cases, other planes may be moved without being introduced at ⁇ 111 ⁇ . Also in that case, it is usually immediately changed to ⁇ 111 ⁇ . 4) Most of the dislocations introduced into the silicon single crystal produced by the CZ method occur when the seed crystal is brought into contact with the silicon melt.
- Table 1 shows the angle between crystal planes as the slip plane where dislocations move and the type of crystal to be pulled up.
- the dislocation generated by heat shock or misfit is a necking step for reducing the diameter of the silicon single crystal as shown in FIG.
- ⁇ 111 ⁇ which is the sliding surface of the silicon single crystal
- Dislocations that have moved on the slip plane reach the surface of the silicon single crystal.
- the surface of the silicon single crystal is considered to be the end point of dislocation.
- the initial dislocations introduced by heat shock or misfit may extend in the crystal growth direction. This phenomenon occurs regardless of the diameter of the product and the diameter of the neck portion during necking.
- the dislocation does not move ⁇ 111 ⁇ on the slip plane, extends in a direction perpendicular to the crystal growth interface between the silicon single crystal and the silicon melt, and then moves to the slip plane without moving to the slip plane. Progress in the growth direction. Dislocations that have progressed in the crystal growth direction in this way become axial dislocations.
- the axial dislocation does not reach the surface of the silicon single crystal even if the diameter of the silicon single crystal is subsequently increased to the diameter of the product.
- Such a silicon single crystal having axial dislocations has a habit line similar to a silicon single crystal having no axial dislocations, and may not be distinguished from non-defective products in an ingot state.
- the axial dislocation is detected as a defect.
- dislocations extending in the growth direction of the silicon single crystal increase the diameter of the silicon single crystal, or the diameter reaches the product diameter, and the product part moves to ⁇ 111 ⁇ during manufacturing. In some cases, axial dislocations may occur.
- the dislocation introduced by heat shock or misfit and extended parallel to the crystal growth direction can be moved to ⁇ 111 ⁇ during the necking step, the dislocation can be removed at the neck portion. That is, even if the neck portion is not made thinner than necessary or the seed is not heated to an unnecessarily high temperature, it is possible to proceed to a shoulder process in which the diameter of the silicon single crystal is increased with dislocations removed in the neck portion. . This eliminates the influence of dislocations generated in the initial stage of crystal growth in the product. As a result, the number and time of remelting (remelting) the silicon single crystal in which axial dislocations are generated in the initial stage of crystal growth can be suppressed.
- the inventors of the present invention have considered that if such conditions can be clarified, it is possible to grow a silicon crystal having a large weight without axial dislocation at a low cost, and the present invention has been completed.
- the present invention is a method for moving dislocations that do not exist in ⁇ 111 ⁇ to ⁇ 111 ⁇ at the stage of forming the neck portion. This method employs means for changing the shape of the interface between the silicon single crystal and the silicon melt when the neck portion is formed. X-ray topography in synchrotron radiation equipment is used for checking the conditions.
- the method for producing a silicon single crystal according to the present invention includes the following steps in the method for producing a silicon single crystal in which the silicon single crystal is pulled by the CZ method.
- a dipping process in which the seed crystal is brought into contact with the silicon melt to start pulling.
- a straight body process that pulls up the single crystal straight body that becomes a silicon wafer.
- a difficult-to-remove dislocation removal step of removing difficult-to-remove dislocations generated in the dip step before the straight body step.
- the difficult-to-remove dislocations may be removed by extending outwardly according to crystal pulling or by annihilating them in a loop shape.
- the solid-liquid interface shape between the silicon melt and the silicon single crystal may be deformed from the melt surface to move the extension direction of the difficult-to-remove dislocation from the crystal growth direction.
- the extension direction of the difficult-to-removal dislocations is changed from the crystal growth direction by changing from the central position the portion where the tangential plane of the solid-liquid interface between the silicon melt and the silicon single crystal is parallel to the melt surface. It may be moved.
- fluctuation of the solid-liquid interface state between the silicon melt and the silicon single crystal may be increased to move the extension direction of the difficult-to-remove dislocation from the crystal growth direction.
- the rotation of the silicon single crystal relative to the silicon melt may be reduced to increase the fluctuation of the solid-liquid interface state.
- the magnetic field strength applied to the silicon melt may be reduced to increase the fluctuation of the solid-liquid interface state.
- fluctuations in the solid-liquid interface state may be increased by molten-metal surface vibrations generated due to the quartz glass crucible storing the silicon melt.
- the fluctuation of the solid-liquid interface state may be increased by heating the silicon single crystal asymmetrically with respect to the growth axis.
- a temperature distribution is formed so that the solid-liquid interface between the silicon melt and the silicon single crystal is asymmetric with respect to the growth axis, and the extension direction of the difficult removal dislocation is moved from the crystal growth direction. May be.
- the silicon single crystal may be heated asymmetrically with respect to the growth axis so that the solid-liquid interface is asymmetric with respect to the growth axis.
- the method for producing a silicon single crystal according to the present invention forms a dislocation removing portion that removes dislocations generated in the dipping step by extending the dislocations generated in the dip step in the outward direction or by annihilating them in a loop shape in the difficult removal dislocation removing step.
- a dislocation-free determination step of determining that dislocations are removed based on the dislocation behavior information.
- the method for producing a silicon single crystal according to the present invention forms a dislocation removing portion that removes dislocations generated in the dipping step by extending the dislocations generated in the dip step in the outward direction or by annihilating them in a loop shape in the difficult removal dislocation removing step.
- the following steps are included.
- the high-energy radiation light may be 40 keV to 70 keV energy and may be irradiated to the dislocation removing unit as a rotation state at a rotation speed of 0.1 to 30 rpm.
- the silicon single crystal of the present invention is produced by any one of the production methods described above.
- the silicon wafer of the present invention is manufactured from the above silicon single crystal.
- the silicon single crystal manufacturing method of the present invention is a silicon single crystal manufacturing method in which the silicon single crystal is pulled up by the CZ method, and includes a dipping step, a straight body step, and a difficult-to-removal dislocation removal step as described above. This makes it possible for the first time to remove difficult dislocations (axial dislocations) that could not be removed in the past.
- the axial dislocation can be removed before the diameter expansion step of pulling up the shoulder by moving the extension direction of the axial dislocation from the crystal growth direction. Therefore, it becomes possible to pull up a silicon single crystal in which no dislocation extending to the straight body portion exists as an axial dislocation. Therefore, it becomes possible to manufacture a wafer having no axial dislocation from the straight body portion of the silicon single crystal without axial dislocation.
- dislocations are removed by extending outwardly according to crystal pulling or by annihilating them in a loop shape. That is, the dislocation is moved to a slip plane that is different from the crystal growth direction. Then, the dislocations can escape to the outside or be paired with other dislocations. Thereby, generation
- the solid-liquid interface shape between the silicon melt and the silicon single crystal can be deformed from the melt surface to move the extension direction of the difficult-to-remove dislocation from the crystal growth direction.
- the dislocation extension is not ⁇ 111 ⁇ , which is a slip plane, but first moves in that direction because the crystal grows perpendicular to the crystal growth plane. That is, as shown in FIG. 16A, the solid-liquid interface K between the silicon melt 3 and the grown single crystal 6 extends in the normal direction of the tangential plane with the dislocation j as a contact.
- the dislocation j When the solid-liquid interface K is parallel to the liquid surface 30, that is, when the solid-liquid interface K is in a flat state, the dislocation j extends in the direction indicated by the arrow in the melt 3 as shown in FIG. Go. Accordingly, the dislocation j in the axial direction (crystal growth direction) shown in the vertical direction in the drawing extends in the crystal growth direction.
- the dislocation j When the dislocation j extends in the crystal growth direction as it is, the position of the dislocation j changes in the radial direction at the enlarged diameter portion of the silicon single crystal, but is not erased. Therefore, the dislocation j extending in the crystal growth direction may be an axial dislocation that exists in the straight body portion so as to extend in the crystal growth direction.
- the deformation of the solid-liquid interface shape between the silicon melt and the silicon single crystal from the surface of the melt means that the solid state between the silicon melt 3 and the grown silicon single crystal 6 is shown in FIG. This includes making the liquid interface K1 convex downward. Further, as shown in FIG. 16C, the solid-liquid interface K2 between the silicon melt 3 and the grown silicon single crystal 6 is formed in a convex shape upward. As a result, the dislocation j extends in the normal direction of the tangential plane with the dislocation j as a contact at the solid-liquid interface K1, as shown in FIG. Further, as shown in FIG.
- the dislocation j extends in the normal direction of the tangential plane with the dislocation j as a contact at the solid-liquid interface K2 as the crystal is pulled. Therefore, the dislocations j extend toward the outside of the silicon single crystal as shown in FIG. Alternatively, as shown in FIG. 16C, a plurality of dislocations j gather in the direction of the central axis of the silicon single crystal. As a result, the dislocation j can be removed outside the silicon single crystal, or can be eliminated by annihilation with other dislocations. Therefore, the dislocation j can be prevented from becoming an axial dislocation, that is, a dislocation that is difficult to remove.
- the relationship between the solid-liquid interface shape and the direction of dislocation propagation can be summarized as follows.
- A When the interface shape is flat, the dislocation extends in the vertical direction (the central axis direction of the silicon single crystal, the vertical direction).
- B When the interface shape protrudes downward, the dislocation extends toward the outer periphery of the silicon single crystal
- c When the interface shape is convex upward, the dislocation extends toward the inside of the silicon single crystal.
- These solid-liquid interface shapes can be controlled by the pulling speed. That is, when the pulling speed is increased, the shape of the interface becomes convex upward. Further, when the pulling speed is reduced, the shape of the interface becomes convex downward.
- more precise control can be performed by changing the magnitude of the magnetic field to be applied, the rotational speed of the crucible, the rotational speed of the crystal, and the like.
- the diameter of the crystal may vary due to a change in the pulling speed. When the pulling rate is reduced in order to remove dislocations and prevent the occurrence of axial dislocations, the dislocations can be removed in the outward direction of the crystal, and the occurrence of axial dislocations can be prevented.
- the diameter is reduced to a certain extent so that the crystal to be pulled can be held.
- the dislocations can be eliminated by disappearing toward the center, or they can be removed as they are, so that the occurrence of axial dislocations can be prevented.
- the range of the crystal diameter variation is not particularly limited as long as it does not affect the pulling up of the straight body of the silicon single crystal.
- the dislocation extension direction shifts from the pulling direction (axial direction) of the silicon single crystal due to a change in pulling speed.
- the extension direction of the difficult-to-removal dislocations is changed from the crystal growth direction by changing the portion where the tangential plane of the solid-liquid interface between the silicon melt and the silicon single crystal is parallel to the melt surface Can be moved.
- Both the solid-liquid interface K1 having a downwardly convex shape shown in FIG. 16B and the solid-liquid interface K2 having an upwardly convex shape shown in FIG. 16C rotate around the crystal center. It is a rotationally symmetric shape with an axis. Accordingly, the shape is axisymmetric with respect to the axis of the central axis of the silicon single crystal. Dislocations may develop in line with the central axis of the silicon single crystal.
- dislocations may exist at the crystal center.
- the dislocation at the center of the crystal does not change the extension direction from the central axis direction.
- the portion where the tangential plane of the solid-liquid interface between the silicon melt and the silicon single crystal is parallel to the melt surface from the center position includes the following.
- the solid-liquid interface K3 between the silicon melt 3 and the grown single crystal 6 is convex downward.
- the shape of the solid-liquid interface K3 is changed so as not to be axially symmetric so that the portion Kd in which the normal line of the tangential plane is the vertical direction, that is, the crystal center axis direction, is separated from the crystal center position Kc.
- the solid-liquid interface K4 between the silicon melt 3 and the grown single crystal 6 is convex upward.
- the solid-liquid interface K3 shape is changed so as not to be axially symmetric so that the portion Kd in which the normal line of the tangential plane is vertical, that is, the crystal central axis direction is separated from the crystal center position Kc. .
- Control for shifting the shape of the solid-liquid interface K3 shown in FIG. 17A or the solid-liquid interface K4 shown in FIG. 17B from axial symmetry includes the following operations.
- the rotation ratio between the silicon melt 3 and the grown crystal 6 is made zero, that is, the crystal rotation with respect to the melt is stopped. Stop the applied magnetic field during pulling.
- the temperature distribution of the grown crystal is distorted so that it is not symmetric with respect to the central axis of the crystal. Changing the state of the silicon melt from a state suitable for crystal growth symmetrical to the central axis of the crystal.
- the convection in the silicon melt fluctuates from the state controlled by the magnetic field.
- the crystal growth is not axisymmetric with respect to the central axis of the crystal.
- crystals do not have a uniform diameter but grow. That is, the temperature distribution which is axisymmetric with respect to the central axis of the silicon single crystal is broken at the solid-liquid interface. Then, the portion where the normal line of the tangent plane of the solid-liquid interface is in the vertical direction, that is, the central axis direction of the crystal can be moved to a position away from the center of the crystal.
- the temperature control means for heating or cooling a part of the crystal can employ the following configuration.
- a structure in which the temperature adjusting means rotates following the rotation of the crystal. A configuration that can be switched on and off following the rotation of the crystal.
- Such temperature adjusting means may be installed at a fixed position.
- the temperature adjusting means may form a temperature distribution that is not axially symmetric in the crystal so as not to shield the silicon melt from a part of the crystal.
- a notch that is provided in a furnace for pulling up a silicon single crystal and that rotates in synchronization with the crystal may be provided near the lower end of a heat shield that reduces heat radiated from the silicon melt to the crystal.
- a lifting device provided with a notch that can be opened and closed at the lower end of the heat shield and provided with a rotating means for rotating the heat shield in synchronization with the rotation of the crystal may be used.
- the heating position may be rotated following the rotating crucible.
- a part of the quartz glass crucible for example, a state in the range of about a quarter in the circumferential direction of the inner wall, is different from the other parts, and bumping that is considered to be the cause of the vibration of the silicon melt surface (liquid level) The occurrence rate may be increased.
- the shape (state) of the solid-liquid interface can be changed by changing parameters such as pulling speed, applied magnetic field strength, crucible rotation speed, crystal rotation speed, crystal and silicon melt heating state, etc. Any method can be employed as long as the method is shifted from axial symmetry.
- fluctuation of the solid-liquid interface state between the silicon melt and the silicon single crystal may be increased to move the extension direction of the difficult-to-remove dislocation from the crystal growth direction.
- this fluctuation of the solid-liquid interface acts to shift the dislocation growth direction from the crystal growth direction by various means. Then, dislocations can be eliminated from the crystal so as to disappear, or can be eliminated from each other, thereby preventing the formation of axial dislocations.
- the fluctuation of the solid-liquid interface state may be increased by reducing the rotation of the silicon single crystal relative to the silicon melt.
- the magnetic field strength applied to the silicon melt may be reduced to increase the fluctuation of the solid-liquid interface state.
- fluctuations in the solid-liquid interface state may be increased by molten-metal surface vibrations generated due to the quartz glass crucible storing the silicon melt.
- the fluctuation of the solid-liquid interface state may be increased by heating the silicon single crystal asymmetrically with respect to the growth axis.
- a temperature distribution is formed so that the solid-liquid interface between the silicon melt and the silicon single crystal is asymmetric with respect to the growth axis, and the extension direction of the difficult removal dislocation is moved from the crystal growth direction. May be.
- the solid-liquid interface may be asymmetric with respect to the growth axis by heating the silicon single crystal asymmetrically with respect to the growth axis.
- the method for producing a silicon single crystal according to the present invention forms a dislocation removing portion that removes dislocations generated in the dipping step by extending the dislocations generated in the dip step in the outward direction or by annihilating them in a loop shape in the difficult removal dislocation removing step.
- a dislocation-free determination step of determining that dislocations are removed based on the dislocation behavior information.
- a lifting condition setting step of determining a dislocation-free implementation raising condition based on the determination of dislocation-free in the non-dislocation determination step makes it possible to clarify the behavior of dislocations whose behavior has not been clarified. Further, this dislocation can be eliminated so as to escape outward along with the growth of the dislocation removal portion (dislocation-free portion). Alternatively, it is possible to easily obtain a pulling condition for expanding the diameter of the silicon single crystal after eliminating the dislocation as a loop and eliminating the dislocation.
- the dislocation state is determined from the acquired information in the non-dislocation determination step. Therefore, it is possible to accurately grasp the dislocation behavior in the dislocation removal unit (dislocation-free unit). As a result, dislocation removal due to the occurrence of a loop, which has not been known in the past, can be used effectively. For this reason, it is not necessary to make the diameter of the dislocation-free portion, conventionally called the neck portion, smaller than necessary. Thereby, even if the weight of the crystal pulled up from the silicon melt increases, the load can be supported by the dislocation-free portion. Therefore, a silicon single crystal having a larger diameter than before can be pulled out of the silicon melt.
- the method for producing a silicon single crystal according to the present invention forms a dislocation removing portion that removes dislocations generated in the dipping step by extending the dislocations generated in the dip step in the outward direction or by annihilating them in a loop shape in the difficult removal dislocation removing step.
- a dislocation-free determination step of determining that dislocations are removed based on the dislocation behavior information.
- the diameter expansion step is started.
- the dislocations are removed (dislocation-free) in the dislocation removal portion (dislocation-free portion)
- the shoulder portion (expanded diameter portion) and the straight body portion can be pulled up. Therefore, dislocations are removed, and dislocation-free crystals having no axial dislocations can be pulled up safely and easily.
- the high-energy radiation light may have an energy of 40 keV to 70 keV.
- the dislocation removing unit may be irradiated with the high energy radiation light in a rotational state at a rotational speed of 0.1 to 30 rpm.
- the three-dimensional information of dislocation can be acquired.
- information can be acquired nondestructively.
- the irradiation with high energy radiation light in a rotating state includes the following.
- a dislocation removal part rotates around the central axis in the crystal growth direction as a rotation center axis, and this dislocation-free part is irradiated with high energy radiation.
- irradiation with high energy synchrotron radiation for obtaining information on dislocation is performed in a relative motion state in which the irradiation source of high energy synchrotron radiation and the dislocation-free part are comparable to the above rotation.
- a dipping process In the initial stage of pulling the silicon single crystal by the CZ method, a dipping process, a neck process and a shoulder forming process are performed.
- the seed crystal In the dipping process, the seed crystal is lowered while rotating, and its tip is immersed in the surface of the silicon melt. After dipping the tip of the seed crystal in the silicon melt, the descent of the seed crystal is stopped. Then, the silicon melt and the seed crystal are sufficiently blended.
- the dipping process is performed after a predetermined time has elapsed after melting the crystal raw material.
- the temperature of the liquid surface when the seed crystal is brought into contact with the silicon melt is too high, the tip of the seed crystal melts and is separated from the melt.
- the temperature of the silicon melt surface is too low, crystals grow around the tip of the seed crystal. Then, the crystal protrudes around the seed crystal on the surface of the melt.
- conforming the seed crystal and the silicon melt includes the following. Estimate the temperature of the surface (liquid level) of the silicon melt by observing the shape of these interfaces when the seed crystal is brought into contact with the silicon melt. Control the heater power based on the estimated liquid surface temperature to adjust the heat input to the silicon melt. In other words, conforming the seed crystal and the silicon melt includes the following operations.
- the meniscus is not formed only when the seed crystal and the silicon melt are mixed.
- the meniscus is also formed at the interface between the crystal and the melt during the growth of the crystal, such as a neck process following the process of allowing the seed crystal and the silicon melt to blend.
- the seed crystal is adapted to the melt in the dipping process, the neck part having a predetermined length is formed in the neck process, and then the formed neck part is adapted to the melt again. Form the neck.
- the length of the neck part required for non-dislocation to remove the dislocation from the neck part can be shortened, and the non-dislocation rate can be improved.
- the neck process which raises a seed crystal and forms a neck part is implemented.
- a shoulder portion and a body portion of a single crystal are formed.
- the neck portion may be continuously formed by fitting the neck portion into the melt.
- the transverse magnetic field applied to the melt may be performed in the range of 2000G to 4000G.
- the length of the neck portion formed first in the neck step may be 20 mm or more.
- the neck portion after raising the temperature of the melt at the time of forming the neck portion, the neck portion may be adapted to the melt. Further, the temperature of the heater for melting the crystal raw material in the crucible may be measured (temperature measurement), and the temperature of the melt may be adjusted by controlling the temperature of the heater based on the temperature measurement result.
- the above-mentioned adjustment of the seed crystal to the melt (silicon melt) and the conformation of the neck portion to the melt include the meniscus shape of the contact interface when the crystal is brought into contact with the melt, for example, Includes observing the overhang of crystal habit lines. That is, the temperature of the surface of the melt is estimated, the heater power (electric power) is controlled based on the temperature, the amount of heat input to the melt is adjusted, and the temperature of the surface of the melt is stabilized.
- the seed crystal and the neck portion are adapted to the melt, dislocations are easily removed.
- the silicon single crystal of the present invention is produced by any one of the production methods described above.
- the silicon wafer of the present invention is manufactured from the above silicon single crystal.
- the method for producing a silicon single crystal of the present invention includes the following steps in the method for producing a silicon single crystal in which the silicon single crystal is pulled up by the CZ method.
- a dipping process in which the seed crystal is brought into contact with the silicon melt to start pulling.
- a dislocation removing step for forming a dislocation removing portion that removes dislocations generated in the dip step by extending outwardly according to crystal pulling or by annihilating them in a loop shape.
- a diameter expansion process that raises the shoulder that expands to the required diameter.
- a straight body process that raises the straight body.
- a dislocation behavior information acquisition step of detecting dislocation behavior information that is a three-dimensional behavior of dislocations in the dislocation removal unit by irradiating the dislocation removal unit with high energy radiation.
- a diameter expansion process that raises the shoulder that expands to the required diameter A straight body process that raises the straight body.
- the diameter expansion step may be started based on the determination of dislocation-free in the dislocation-free determination step.
- the high-energy radiation light may have an energy of 40 keV to 70 keV, and may be irradiated to the dislocation removing unit as a rotation state at a rotation speed of 0.1 to 30 rpm.
- the method for producing a silicon single crystal of the present invention includes the following steps in the method for producing a silicon single crystal in which the silicon single crystal is pulled up by the CZ method.
- a dipping process in which the seed crystal is brought into contact with the silicon melt to start pulling.
- a dislocation removing step for forming a dislocation removing portion that removes dislocations generated in the dip step by extending outwardly according to crystal pulling or by annihilating them in a loop shape.
- a diameter expansion process that raises the shoulder that expands to the required diameter.
- a straight body process that raises the straight body.
- a dislocation behavior information acquisition step of detecting dislocation behavior information that is a three-dimensional behavior of dislocations in the dislocation removal unit by irradiating the dislocation removal unit with high energy radiation.
- a dislocation-free determination step of determining that dislocations are removed based on the dislocation behavior information.
- the dislocation state is determined from the information acquired in the previous process. Therefore, it is possible to accurately grasp the dislocation behavior inside the dislocation removal unit (dislocation-free unit). Therefore, it is possible to effectively use the removal of dislocations due to the occurrence of a loop that was not previously known.
- the diameter of a silicon single crystal is made small, the diameter of the dislocation-free part conventionally called the neck part can be made larger than before. Therefore, even if the weight of the crystal pulled from the silicon melt increases, the silicon single crystal can be supported by the dislocation-free portion and the silicon single crystal having a large diameter can be pulled. Therefore, it is possible to omit an extra procedure related to a dip process or the like that increases the manufacturing time and the work process. In addition, it is possible to pull up a large silicon single crystal having a diameter of about 450 mm in a dislocation-free state having no axial dislocation.
- the method for producing a silicon single crystal of the present invention includes the following steps in the method for producing a silicon single crystal in which the silicon single crystal is pulled up by the CZ method.
- a dipping process in which the seed crystal is brought into contact with the silicon melt to start pulling.
- a dislocation removing step for forming a dislocation removing portion that removes dislocations generated in the dip step by extending outwardly according to crystal pulling or by annihilating them in a loop shape.
- a diameter expansion process that raises the shoulder that expands to the required diameter.
- a straight body process that raises the straight body.
- a dislocation behavior information acquisition step of detecting dislocation behavior information that is a three-dimensional behavior of dislocations in the dislocation removal unit by irradiating the dislocation removal unit with high energy radiation.
- the silicon single crystal is pulled up to form the shoulder part (expanded part) and the straight body part. Can do. Therefore, dislocation-free crystals having no axial dislocations in the shoulder portion and the straight body portion can be pulled up safely and easily.
- the high energy radiation light may have an energy of 40 keV to 70 keV.
- high energy synchrotron radiation has sufficient energy to acquire information on dislocation states necessary for growth of dislocation-free crystals.
- the dislocation removing unit may be irradiated with the high energy radiation light in a rotational state at a rotational speed of 0.1 to 30 rpm.
- the three-dimensional information of dislocation can be acquired.
- non-destructive three-dimensional information of dislocations can be acquired.
- the irradiation with high energy radiation light in a rotating state includes the following.
- the dislocation removing unit (dislocation-free unit) rotates with the central axis in the direction of crystal growth as the rotation center axis, and the dislocation removing unit is irradiated with high energy radiation.
- High energy synchrotron radiation for acquiring dislocation information is performed in a relative motion state where the irradiation source of the high energy synchrotron radiation and the dislocation removal unit are comparable.
- dislocation-free portion is made dislocation-free, the silicon single crystal is pulled up to increase the diameter, and the straight body portion can be grown.
- dislocations generated in the step of bringing the seed crystal into contact with the silicon melt can be removed, and dislocation-free can be realized.
- the pulling conditions for the silicon single crystal that can be dislocation-free can be accurately determined.
- step S03 is an explanatory view illustrating step S03 according to the third embodiment.
- A) And (b) is explanatory drawing explaining process S03 which concerns on 3rd Embodiment. It is image data of the dislocation-free part acquired in step S12 according to the third embodiment, (a) shows a state where dislocations are not removed, and (b) and (c) show dislocations removed. Indicates the state.
- FIG. 1 is a schematic front view showing an apparatus for producing a silicon single crystal in the present embodiment.
- a CZ furnace which is a silicon single crystal manufacturing apparatus using the Czochralski method (hereinafter referred to as CZ method) includes a crucible 1, a heater 2, a pulling shaft 4, a seed chuck 5, , A heat shield (heat shield) 7 and a magnetic field generator (magnetic field supply device) 9 are provided.
- the crucible 1 is disposed in the center of the chamber and has a double structure having a quartz crucible 1a and a graphite crucible 1b.
- the quartz crucible 1a accommodates the silicon melt 3 inside.
- the graphite crucible 1b is disposed outside the quartz crucible 1a and holds the quartz crucible 1a.
- the crucible 1 is rotated and raised / lowered by a support shaft (pedestal) 1c.
- the heater 2 is disposed outside the crucible 1.
- a resistance heater can be used as the heater 2.
- the heater 2 is not limited to a resistance heater as long as the temperature of the silicon melt 3 accommodated in the crucible 1 is heated to a temperature equal to or higher than the melting point and can be maintained.
- the pulling shaft 4 rotates at an arbitrary rotational speed around an axis parallel to the vertical direction. Further, the lifting shaft 4 moves at an arbitrary speed in an axial direction parallel to the vertical direction.
- the seed chuck 5 is provided at the lower end of the pulling shaft 4 and holds the silicon seed crystal T.
- the pulling shaft 4 is lowered and the seed crystal T attached to the seed chuck 5 is immersed in the silicon melt 3. Thereafter, while rotating the crucible 1 and the pulling shaft 4, the pulling shaft 4 is raised to pull up the seed crystal T and the silicon single crystal 6.
- the heat shielding portion 7 is provided above the crucible 1 so as to surround the side surface of the growing silicon single crystal 6 and to surround a portion above the liquid surface of the silicon melt 3.
- the heat shielding portion 7 has a cylindrical graphite outer shell, and the outer shell is filled with graphite felt.
- the heat shielding portion 7 is provided between the heater 2 and the silicon melt 3 surface and the side surface portion of the silicon single crystal 6 to block radiant heat.
- the inner surface of the heat shield 7 is inclined so that the inner diameter of the heat shield 7 gradually decreases from the upper end toward the lower end.
- the outer surface of the upper part of the heat shielding part 7 is inclined in the same manner as the inner surface.
- the outer surface of the lower part of the heat shielding part 7 is substantially parallel to the vertical direction.
- the thickness of the lower part of the heat shielding part 7 is thicker toward the lower side closer to the silicon melt 3.
- the width (thickness) W in the radial direction of the lower part of the heat shielding part 7 is, for example, about 50 mm.
- the inclination ⁇ with respect to the vertical direction of the inner surface of the heat shielding portion 7 that is the inverted truncated cone surface is, for example, about 21 °.
- the height H1 from the liquid surface of the silicon melt 3 to the lower end of the heat shield 7 is, for example, in the range from about 10 mm to about 250 mm.
- the height H1 may be 50 mm or 100 mm, for example. Moreover, you may set the height H1 in each process mentioned later, respectively.
- the magnetic field generator 9 is disposed outside the heater 2.
- the magnetic field generated by the magnetic field generator 9 may be a horizontal magnetic field or a cusp magnetic field.
- the strength of the horizontal magnetic field may be in a range from 2000 G to 5000 G (from 0.2 T to 0.5 T).
- the strength of the horizontal magnetic field may be in the range of 3000G to 4000G (0.3T to 0.4T).
- a more preferable range of the strength of the horizontal magnetic field is 3000G to 3500G (0.30T to 0.35T).
- the height of the magnetic field center may be from 150 mm below the liquid surface of the silicon melt 3 to 100 mm above the liquid surface.
- a more preferable height of the magnetic field center is in a range from 75 mm below the liquid level to 50 mm above the liquid level.
- the magnetic field generator 9 may not generate a magnetic field.
- the manufacturing method of this embodiment includes a pulling condition setting step S00, a pulling preparation step S01, a dipping step S02, a dislocation removing step S03, a diameter expanding step S04, and a straight body step S05. , Tail process S06, measurement preparation process S11, dislocation behavior information acquisition process S12, and non-dislocation determination process S13.
- a pulling condition that can make the silicon single crystal 6 dislocation-free is set.
- the pulling conditions include the following. Holding time of the seed crystal (seed) T before contact with the silicon melt 3. The contact time of the silicon seed crystal T with the silicon melt 3 and the temperature of the seed crystal T based on the contact time. The distance (height H1) between the heat shield 7 and the silicon melt 3. A radial width W of the lower end portion of the heat shield portion 7. The conditions of the atmosphere in the furnace. The rotational speed and pulling speed of the pulling shaft 4 when pulling up the silicon single crystal. The number of rotations of the crucible 1. The length in the pulling direction of a dislocation-free portion (neck portion, dislocation removal portion) N described later. Application state of magnetic field.
- the heating state or temperature distribution of the grown silicon single crystal can be set to arbitrary values in the initial state before the production of the silicon single crystal 6 is started. Note that as the pulling conditions for the silicon single crystal 6 in step S00, data obtained by previously pulling the silicon single crystal 6 a plurality of times under different conditions may be used. In this case, the pulling conditions are selected based on the specifications of the silicon single crystal 6 to be manufactured.
- step S01 high-purity silicon polycrystal is put into the crucible 1.
- the weight of the silicon polycrystal to be added is in the range from about 100 kg to about 400 kg.
- a dopant for setting the product to a predetermined resistivity is added to the silicon melt 3 so as to have a predetermined concentration. Further, the concentration of carbon and nitrogen for setting or adjusting the resistivity or gettering ability of the product is adjusted. In some cases, the dopant may not be added.
- 300 kg of silicon polycrystal is put into the crucible 1.
- the concentration of the dopant is adjusted so that, for example, the resistance value of the straight body portion 6b of the silicon single crystal 6 to be manufactured is 12 ⁇ cm.
- the atmosphere inside the CZ furnace is an inert gas, and the pressure of the inert gas is adjusted within a range from 1.3 kPa to 13.3 kPa (from 10 torr to 100 torr).
- the atmosphere inside the CZ furnace is, for example, Ar gas having a pressure of 50 Torr (6.666 kPa).
- the atmosphere inside the CZ furnace may contain hydrogen gas.
- a horizontal magnetic field of, for example, 3000 G (0.3 T) is generated by the magnetic field generator 9, and the silicon polycrystal is heated and melted by the heater 2.
- the height of the center of the magnetic field is set in a range from 75 mm below the liquid surface of the silicon melt 3 to 50 mm above the liquid surface.
- the transverse magnetic field applied to the silicon melt 3 may be within a range from 2000 G to 4000 G.
- step S02 as shown in FIG. 3A, the seed crystal T attached to the seed chuck 5 is brought close to the silicon melt 3 and heated while being held for a predetermined time. Thereafter, the seed crystal T is lowered while being rotated, and is brought into contact with the silicon melt 3 as shown in FIG. And the lower end part of the seed crystal T is immersed in the silicon melt 3 (dip process). At this time, a dislocation t is generated at the lower end of the seed crystal T due to heat shock (see arrow A1). At this time, the respective temperatures are set so that the temperature state of the seed crystal T and the silicon melt 3 falls within a predetermined range. Specifically, the surface temperature of the silicon melt 3 is adjusted by adjusting the heating state of the heater 2 so that a meniscus having a predetermined shape is formed around the tip of the seed crystal T.
- step S03 as shown in FIG. 3C, the silicon single crystal 6 is pulled up while the crucible 1 and the pulling shaft 4 are rotated. At this time, the shape of the interface between the silicon single crystal 6 and the silicon melt 3 is formed in a concave shape (see arrow A2).
- the conditions set in step S00 are used as the conditions for pulling up the silicon single crystal 6.
- the dislocations generated in the step S02 extend toward the outside in the radial direction of the silicon single crystal 6 and disappear, or disappear in pairs in a loop shape. Thereby, as shown in FIG. 3D and FIG. 3E, the dislocation t is removed, and a dislocation-free neck portion, that is, a dislocation-free portion N is formed (see arrow A3). .
- the interface between the silicon single crystal grown on the lower end portion of the seed crystal T and the silicon melt 3 The shape of the (meniscus) becomes a predetermined shape.
- the shape of the meniscus formed at the lower end of the seed crystal T or the silicon single crystal 6 varies depending on the heating conditions of the heater 2 and the pulling conditions such as the lifting speed of the pulling shaft 4.
- the shape of the meniscus formed at the lower end of the seed crystal T or the silicon single crystal 6 can be adjusted by adjusting the temperature of the seed crystal T and the silicon melt 3 to a temperature within a predetermined range. .
- the dislocation t below the dislocation t generated in step S02 is the diameter of the silicon single crystal 6. It is formed to extend outward in the direction.
- crystal habit lines are formed on the outer periphery of the silicon single crystal 6 (see arrow A4). The portion inside the crystal habit line in the radial direction is in a dislocation-free state having no dislocations.
- the silicon single crystal 6 grows, as shown in FIG. 3E, the lower side crystal habit line is continuous (see arrow A5), and dislocation-free portions are continuously formed (see FIG. 3E). (See arrow A6).
- dislocation-free initial cone is formed below the dislocation-free portion (see arrow A7).
- the dislocation t extends toward the outside in the radial direction of the silicon single crystal 6 and disappears, or disappears in a loop shape. Thereby, the dislocation-free part N is formed.
- step S04 the diameter of the silicon single crystal 6 is linearly increased by controlling the pulling speed of the silicon single crystal 6, the rotation speed of the pulling shaft 4, the rotation speed of the crucible 1, and the heating conditions of the heater 2.
- the diameter of the lower side of the dislocation-free portion N in which the dislocation-free portion of the silicon single crystal 6 shown in FIG. As shown in FIG. 1, a conical shoulder portion 6 a is formed on the lower side of the dislocation-free portion N of the silicon single crystal 6.
- step S05 the pulling shaft 4 is pulled up to a predetermined length while maintaining the diameter of the silicon single crystal 6 at, for example, 300 mm or 450 mm, which is the diameter of the silicon wafer to be the product.
- the cylindrical straight body part 6b with a constant diameter is formed in the silicon single crystal 6 (straight cylinder process).
- step S06 the diameter of the silicon single crystal 6 is linearly reduced by controlling the pulling speed of the silicon single crystal 6, the rotation speed of the pulling shaft 4, the rotation speed of the crucible 1, and the heating conditions of the heater 2.
- a conical tail portion (not shown) opposite to the shoulder portion 6a is formed in the silicon single crystal 6.
- the silicon single crystal 6 is separated from the silicon melt 3 by separating the tail portion and the silicon melt 3.
- step S11 preparation is made for measuring the dislocation state of the dislocation-free part N.
- the dislocation-free portion N is separated from the silicon single crystal 6.
- the separated dislocation-free portion N is supported by the support portion R ⁇ b> 1 so that it can rotate about the central axis N ⁇ b> 4 of the silicon single crystal that is coaxial with the pulling shaft 4.
- the support portion R1 is provided so that the direction of the central axis N4 that is the rotation axis can be changed.
- the non-dislocation portion N is irradiated with white X-rays as high energy radiation B from the irradiation portion R, and the non-dislocation portion N is irradiated with white X-rays.
- X-rays are detected by a detection unit d including a CCD (dislocation behavior information acquisition step).
- the irradiation unit R includes an absorber, a shutter, and a diffractometer, and has a shutter / absorber that is used for controlling time resolution and taking measures against heat load.
- the detection unit d has a function as a diffractometer.
- the detection unit d has sufficient performance for detecting white X-ray topography.
- the cross section to be analyzed is sliced to a thickness of about 1.5 mm. Then, the sliced surface to be analyzed is etched with mixed acid, and irradiated with X-rays to observe a transmission diagram. Therefore, only a transmission diagram in a cross section with a predetermined interval can be obtained. For example, images at intervals of 1.5 mm are connected to grasp a change in dislocation state accompanying crystal growth. Therefore, only dislocations propagating obliquely with respect to the pulling axis of the silicon single crystal could be observed.
- White X-rays have a continuous spectrum, and the energy may be in the range from 30 keV to 1 MeV.
- the energy of the white X-ray may be in the range from 40 keV to 100 keV, or in the range from 50 keV to 60 keV.
- the wavelength of white X-rays may be in the range from 0.001 nm to 0.25 nm. Thereby, the state of dislocation in the dislocation-free portion N can be sufficiently observed.
- FIG. 5A is a graph showing the distribution of the number of photons obtained through a 1 mm ⁇ 1 mm slit at a distance of 44 m from the X-ray light source of the irradiation unit R, with the vertical axis representing the number of photons and the horizontal axis representing energy. It is.
- FIG. 5B is a graph showing the distribution of the number of photons obtained through a 1 mm ⁇ 1 mm slit at a distance of 44 m from the X-ray light source of the irradiation unit R, where the vertical axis represents the number of photons and the horizontal axis represents the wavelength.
- the X-ray beam diameter is preferably in the range of 0.01 to 1 times the diameter of the dislocation-free portion N that is the object to be measured.
- the non-dislocation portion N is irradiated with white X-rays having an energy of 40 keV to 70 keV, which is high energy radiation light B, while rotating at a rotational speed of 0.1 rpm to 30 rpm.
- the non-dislocation portion N is irradiated with high energy radiation light while rotating the non-dislocation portion N around the central axis N4 in the crystal growth direction as the rotation axis.
- the high-energy radiation light is irradiated from the irradiation unit R to the non-dislocation unit N while rotating the irradiation unit R about the central axis N4.
- Both the irradiation part R and the dislocation-free part N may be rotated about the axis N4 as a rotation axis. And the three-dimensional information of the dislocation of the dislocation-free part N can be acquired nondestructively by, for example, Fourier transforming the detection result.
- step S12 as shown in FIG. 4, the irradiation angle ⁇ of the high-energy radiation light B is set with respect to the axis N4 of the dislocation-free portion N of the silicon single crystal 6. Then, paying attention to one diffraction spot (for example, 004 diffraction spot), a dislocation-free portion N is rotated to construct a CT image by a topographic image. Thereby, the three-dimensional position information of the dislocation line is obtained. The three-dimensional behavior of dislocations in the dislocation-free part N obtained in this way is recorded as first information. Further, dislocation properties such as Burgers vector are measured by white X-ray topography shown in FIG. In FIG.
- the detection positions d1 to d7 correspond to the diffraction direction of white X-rays.
- Each detection position is, for example, a position where a Laue topograph is acquired at crystal orientations [-1 1 1], [-1 1 3], [0 0 4], [1 -1 3], [1 -1 1]. It corresponds.
- ⁇ 1 in the above crystal orientation means 1 with an overline.
- step S13 it is determined whether or not the dislocation has been removed based on the first information including the three-dimensional behavior of the dislocation acquired in step S12. Specifically, it is determined whether or not dislocation has been removed from the image data of the dislocation-free portion N shown in FIG. That is, as shown in FIG. 8A, when the dislocation extends linearly along the central axis N4, it is determined that the dislocation has not been removed. As shown in FIG. 8B, dislocations are present, but when these are pair-annihilated in a loop shape, it is determined that the dislocation has been removed. As shown in FIG. 8C, when the dislocation cannot be confirmed, it is determined that the dislocation has been removed.
- step S13 the determination of dislocation-free in step S13 is fed back to step S00. That is, when dislocations in the dislocation-free portion N are removed by the pulling conditions initially set in step S00, the pulling conditions are recorded in the database, and the pulling conditions are used in step S00. When dislocations in the dislocation-free portion N are not removed by the pulling conditions initially set in the step S00, the pulling conditions are recorded in the database so that they are not used in the step S00. A new pulling condition that can be dislocation free is set.
- dislocations N are formed, so that dislocations generated in the step of bringing the seed crystal T into contact with the silicon melt 3 are generated by the silicon.
- the single crystal 6 can be removed at the shoulder portion 6a and the straight body portion 6b. Thereby, dislocation-free of the shoulder part 6a and the straight body part 6b of the silicon single crystal 6 can be realized.
- the state of dislocation generation and removal can be accurately grasped by the steps S12 and S13. Further, by repeating the steps S00 to S06 and the steps S11 to S13, it is possible to accurately determine the pulling conditions for the silicon single crystal that can be dislocation-free.
- dislocations in the dislocation-free portion N can be removed without making the neck portion of the silicon single crystal 6, that is, the diameter of the dislocation-free portion N unnecessarily small. Therefore, a large silicon single crystal 6 having a diameter of about 450 mm from which dislocations have been removed can be safely grown by a simple method without requiring any special treatment or apparatus.
- the CZ furnace of the present embodiment includes a crucible 1, a heater 2, a pulling shaft 4, a seed chuck 5, a heat shielding unit 7, a magnetic field generation unit 9, an irradiation unit R, It has a detector d.
- the irradiation part R irradiates the high-energy radiation light B to the dislocation-free part N being pulled up and located in the chamber.
- the detection part d detects the diffracted light of the high energy radiation light B irradiated to the dislocation-free part N.
- the irradiation part R and the detection part d are provided so that the angle ⁇ of the high-energy radiated light B with respect to the pulling axis 4 substantially coincident with the axis N4 can be adjusted.
- the method for manufacturing a silicon single crystal according to the present embodiment includes steps S00 to S06 as in the first embodiment.
- the first implementation described above is that the steps S11 to S13 are not provided after the steps S00 to S06, and the dislocation behavior information acquisition step S22 and the non-dislocation determination step S23 are provided between the steps S03 and S04. It is different from the form.
- step S22 similarly to step S12 described above, the high energy radiated light B is irradiated from the irradiation unit R to the non-dislocation unit N, and the diffracted light is measured by the detection unit d.
- the irradiation of the high energy radiation light B and the detection of the diffracted light to the dislocation-free portion N are performed while pulling up the silicon single crystal inside the CZ furnace.
- step S23 it is determined whether or not the dislocation of the dislocation-free portion N has been removed, as in step S13. Then, when the dislocation of the dislocation-free part N has been removed, the process S04 is started. Further, when the dislocation of the dislocation-free portion N has not been removed, the process returns to step S03, where the dislocation-free portion N is further grown, or the dislocation-free portion N is regrown by meltback. In addition, the pulling condition is fed back to step S00, and a pulling condition different from the fed pulling condition is set.
- the state shown in FIG. 3A to FIG. 3E is measured in real time. For this reason, after confirming that the dislocation t has been removed in the dislocation-free portion N, the step S04 can be started. Therefore, the silicon single crystal 6 in the state where the dislocation t is not removed in the shoulder portion 6a and the straight body portion 6b is not pulled up. Therefore, the time required for manufacturing the silicon single crystal 6 can be shortened. Moreover, the yield in pulling up the silicon single crystal 6 can be remarkably improved.
- Axial dislocations are dislocations that occur at the neck and cannot be removed even if the diameter of the silicon single crystal is reduced by a conventional dash necking method or the like. Conventionally, axial dislocations have been detected as pits when a wafer is manufactured by slicing a straight body portion of a silicon single crystal.
- Axial dislocations can be detected separately from pits by the following method.
- a strain inspection apparatus SIRD: registered trademark
- SirTec manufactured by JENA WAVE can be used to observe the internal stress distribution state by an optical inspection means. taking measurement.
- the wafer is subjected to a saliency treatment in which the wafer is heated for 1 sec or more at a temperature rising rate within a range from 10 ° C./sec to 300 ° C./sec and at a temperature within a range from 900 ° C. to 1250 ° C. Then, the surface properties of the wafer including the manifested distortion are evaluated. In this manifestation process, a large temperature difference is generated in the surface of the wafer due to rapid heating, and thermal stress due to this is generated. Therefore, heating for a long time is not necessary, and heating for a short time of about 1 sec is sufficient.
- dislocations that are detected as pits but are not long enough to penetrate the front and back surfaces of the wafer do not increase in distortion due to thermal stress generated by the revealing process.
- a dislocation whose length in the thickness direction of the wafer is less than about 10% of the thickness of the wafer does not increase in distortion due to thermal stress generated by the revealing process.
- FIG. 11A shows an example of observation of a wafer having a manifested axial dislocation.
- FIG. 11B shows an observation example of a wafer having no axial dislocation.
- the distortion observed at the edge of the wafer is generated by supporting the wafer during the revealing process.
- Axial dislocation occurs at the stage where the seed crystal is brought into contact with the silicon melt. And it exists continuously in the direction in which the silicon single crystal grows, that is, the neck portion, the shoulder portion, and the straight body portion. Axial dislocations appear in specific areas when a silicon single crystal is processed into a wafer. Axial dislocations cannot be removed by conventional dash necking methods.
- a silicon single crystal 60 manufactured by a conventional dash necking method has a seed crystal T0, a neck portion N0, a shoulder portion 60a, a straight body portion 60b, and a tail portion 60c.
- the heat shock dislocation Jn generated in the seed crystal T0 and continuing to the neck portion N0 due to the heat shock when the seed crystal T0 is brought into contact with the silicon melt. Will occur.
- a misfit dislocation Jm occurs in the neck portion N0.
- the axial dislocation J has been observed as follows. First, as shown in FIG. 12, the straight body portion 60b of the silicon single crystal 60 is thinly cut to obtain a plurality of wafers W having a ⁇ 110 ⁇ cross section. The axial dislocation J is observed in the 10 o'clock direction and the 4 o'clock direction when the notches of each wafer W are aligned with the 12 o'clock direction of the watch.
- the axial dislocation J is the center of the silicon single crystal in the range from 120 ° to 135 ° and the range from 315 ° to 350 °, where the position of the notch provided in the ⁇ 100 ⁇ direction is 0 °. It is observed in a region J1 symmetric with respect to the axis. Further, the axial dislocation J is observed in a region that is rotated 90 ° and 45 ° around the central axis in a region that is symmetrical with respect to the central axis of the silicon single crystal. That is, the axial dislocation J extends in the growth direction (center axis direction) of the silicon single crystal in the region J1. In FIG. 12, only the region J1 in the range from 120 ° to 135 ° and the range from 315 ° to 350 ° is illustrated with the notch position being 0 °.
- the axial dislocations J may disappear in a silicon single crystal grown longer than the normal length. However, when a silicon single crystal wafer of a normal length is observed, axial dislocations J exist throughout the entire length of the silicon single crystal, and the axial dislocations J penetrate the silicon single crystal in the central axis direction. There were many.
- the direction in which the heat shock dislocation Jn and the misfit dislocation Jm propagate has the following characteristics.
- the heat shock dislocation Jn and the misfit dislocation Jm usually move on the ⁇ 111 ⁇ plane, which is a silicon slip plane.
- the heat shock dislocation Jn and the misfit dislocation Jm are usually introduced into the ⁇ 111 ⁇ plane.
- the heat shock dislocation Jn and the misfit dislocation Jm rarely are introduced into the ⁇ 111 ⁇ plane and may move to other planes, but immediately move to the ⁇ 111 ⁇ plane.
- most of the heat shock dislocations Jn and misfit dislocations Jm occur when the seed crystal is brought into contact with the silicon melt.
- the heat shock dislocation Jn and the misfit dislocation Jm move along the ⁇ 111 ⁇ plane which is the sliding surface of the silicon single crystal in the step of forming the neck portion. It is considered that the surface of the silicon single crystal is reached.
- the initial heat shock dislocation Jn and misfit dislocation Jm are not the slip surface ⁇ 111 ⁇ plane, but the silicon single crystal and silicon. Extends in a direction perpendicular to the interface with the melt. Thereafter, the heat shock dislocation Jn and the misfit dislocation Jm may extend in the growth direction of the silicon single crystal without moving to the slip plane.
- the heat shock dislocation Jn and the misfit dislocation Jm do not reach the surface of the silicon single crystal even when the diameter of the silicon single crystal increases to the product diameter, and are axial dislocations existing inside the straight body portion. May be.
- a silicon single crystal having axial dislocations in the straight body portion has a habit line similar to a silicon single crystal having no axial dislocations in the straight body portion, and is a non-defective product in an ingot state. It may not be possible to distinguish.
- the axial dislocation is confirmed as a defect when a wafer is manufactured from the ingot.
- the heat shock dislocation Jn and the misfit dislocation Jm extending in the growth direction of the silicon single crystal may move to the ⁇ 111 ⁇ plane during the formation of the shoulder portion or the straight body portion.
- the heat shock dislocation Jn and the misfit dislocation Jm can be moved to the ⁇ 111 ⁇ plane in the step of forming the neck portion, the diameter of the neck portion is not reduced and the seed crystal is not heated to a high temperature. Even so, axial dislocations can be removed. Therefore, if the heat shock dislocation Jn and the misfit dislocation Jm can be moved to the ⁇ 111 ⁇ plane in the neck portion, the product is not affected by the axial dislocation even if the shoulder portion and the straight body portion are formed. In addition, the number and time of remelting at the initial stage of the growth of the silicon single crystal can be suppressed.
- the heat shock dislocation Jn and the misfit dislocation Jm at the time of forming the neck portion progress not perpendicular to the ⁇ 111 ⁇ plane but perpendicular to the interface between the silicon single crystal and the silicon melt. Therefore, in the present embodiment, a method for moving the heat shock dislocation Jn and the misfit dislocation Jm that do not exist in the ⁇ 111 ⁇ plane to the ⁇ 111 ⁇ plane in the step of forming the neck portion will be described. Specifically, the shape of the interface between the silicon single crystal and the silicon melt when the neck portion is formed is controlled. And X-ray topography is used in order to confirm the conditions.
- the method for manufacturing a silicon single crystal according to this embodiment includes steps S01 to S06 and steps S11 to S13, as in the method for manufacturing a silicon single crystal according to the first embodiment shown in FIG. Or similarly to the manufacturing method of the silicon single crystal in 2nd Embodiment shown in FIG. 10, it has process S01 to process S06, process S22, and process S23.
- the present embodiment is different from the first and second embodiments in that the axial dislocation is removed in step S03.
- the CZ furnace of the present embodiment is different from the CZ furnace described in the first embodiment or the second embodiment in that it has a temperature adjusting mechanism of the dislocation-free portion N.
- Other configurations are the same as those of the CZ furnace of the first embodiment or the second embodiment.
- the CZ furnace of this embodiment includes a laser irradiation unit La and a gas supply unit G as a temperature adjustment mechanism of the dislocation-free portion N of the silicon single crystal.
- the laser irradiation unit La and the gas supply unit G are provided so as to rotate around the pulling shaft 4 in synchronization with the rotation of the pulling shaft 4. That is, the laser irradiation unit La and the gas supply unit G heat and cool the silicon single crystal rotating together with the pulling shaft 4 from a predetermined direction.
- the laser irradiation unit La and the gas supply unit G may not be provided so as to rotate around the pulling shaft 4.
- the laser irradiation unit La and the gas supply unit G may be fixed, and the laser beam and the cooling gas may be intermittently irradiated and supplied from the laser irradiation unit La and the gas supply unit G at a predetermined timing.
- a notch 7 ⁇ / b> A that can be opened and closed is formed at the lower end portion of the heat shield portion 7 as a temperature adjustment mechanism of the dislocation-free portion N of the silicon single crystal.
- the cylindrical portion 7a is provided on the upper portion of the heat shielding portion 7, and the lid portion 7b having an opening through which the lifting shaft 4 is passed is provided at the upper end of the cylindrical portion 7a.
- a controller 41 that controls the raising and lowering of the lifting shaft 4 is provided on the lid 7b.
- the heat shield part 7, the cylindrical part 7 a, the lid part 7 b, the control part 41, and the lifting shaft 4 rotate integrally around the axis that coincides with the lifting shaft 4 in synchronization with the rotation of the lifting shaft 4. That is, the heat shield 7 does not shield the heat of the heater 2 only in a predetermined direction of the silicon single crystal that rotates with the pulling shaft 4. In other words, the heater 2 heats the silicon single crystal rotating together with the pulling shaft 4 from the predetermined direction via the notch 7A.
- step S02 first, as shown in FIGS. 3A and 3B, the seed crystal T is brought into contact with the silicon melt 3. Thereafter, in step S03, the pulling shaft 4 is raised, and a silicon single crystal is grown below the seed crystal T to form a dislocation-free portion N.
- step S02 the seed crystal T is lowered while being rotated, and the lower end portion of the seed crystal T is immersed in the silicon melt 3. After the lower end portion of the seed crystal T is immersed in the silicon melt 3, the descent of the seed crystal T is stopped, and the seed crystal T and the silicon melt 3 are sufficiently blended. Then, a part of the lower end portion of the seed crystal T is dissolved in the silicon melt 3.
- step S02 If the silicon melt 3 is in a stable state, when the seed crystal T is brought into contact with the silicon melt 3 in step S02, the surface tension of the silicon melt 3 is present at the interface between the seed crystal T and the silicon melt 3. Acts and a meniscus is formed. However, immediately after the silicon polycrystal as a raw material is melted, the temperature of the silicon melt 3 is largely unstable due to local temperature fluctuations. For this reason, step S02 is performed after a predetermined time has elapsed after melting the silicon polycrystal as a raw material.
- step S02 When the temperature at the liquid surface of the silicon melt 3 is too high, the lower end portion of the seed crystal T is melted and separated when the silicon single crystal is pulled up. When the temperature at the liquid surface of the silicon melt 3 is too low, the crystal grows on the side surface of the lower end portion of the seed crystal T and is in an overhanging state. When the process shifts from step S02 to step S03 in such a state, a new dislocation is generated in the non-dislocation portion N.
- step S03 When shifting from step S02 to step S03, it is necessary that the temperature of the silicon melt 3 is stable. Therefore, after immersing the lower end portion of the seed crystal T in the silicon melt 3, the lower end portion of the seed crystal T is sufficiently adjusted to the silicon melt 3, and the temperature of the silicon melt 3 is stabilized. The process proceeds to S03.
- the shape of the interface between the seed crystal T or the silicon single crystal and the silicon melt 3 is immersed after the seed crystal T is immersed in the silicon melt 3. Observe. Also, observe the interface to observe the overhang of crystal habit lines. Then, the temperature of the liquid surface of the silicon melt 3 is estimated from the shape of the interface between the seed crystal T or the silicon single crystal and the silicon melt 3 and the protrusion of the crystal habit line. And the electric power supplied to the heater 2 is controlled based on the estimated temperature, and the heat input to the silicon melt 3 is adjusted.
- the silicon single crystal is pulled up to a predetermined length in the step S03 to form the dislocation-free portion N with a predetermined length.
- the length of the dislocation-free portion N formed after the seed crystal T is made to conform to the silicon melt 3 is desirably 20 mm or more.
- the lower end portion of the formed dislocation-free portion N having a predetermined length is made to conform to the silicon melt 3 in the same manner as the seed crystal T, and then the dislocation-free portion N is formed to a predetermined length.
- step S03 the lower end portion of the seed crystal T is adjusted to the silicon melt 3 in a state where the temperature of the silicon melt 3 is controlled as described above. Forming N. And after making the lower end part of the neck part of the predetermined length formed into the silicon melt 3 in the state where temperature control was carried out similarly to the lower end part of the seed crystal T, the dislocation-free part N having a predetermined length was further added. Form. Thereby, the length of the dislocation-free portion N necessary for dislocation-freeness can be shortened, and dislocations and axial dislocations in the dislocation-free portion N can be reliably removed.
- step S03 after the temperature of the dislocation-free portion N is raised to a temperature higher than the temperature of the liquid surface of the silicon melt 3, the dislocation-free portion N may be adapted to the silicon melt 3. . Furthermore, the temperature of the heater 2 at the time of melting the silicon polycrystal as a raw material may be measured, and the temperature of the heater 2 may be controlled based on the measurement result to adjust the temperature of the silicon melt.
- the silicon single crystal grows substantially perpendicular to the interface K with the silicon melt 3 on which the crystal is grown. Therefore, as shown in FIG. 16A, when the interface K between the silicon single crystal and the silicon melt 3 is flat, the dislocation j progresses to the ⁇ 111 ⁇ plane that is the sliding surface of the silicon single crystal. Instead, it develops in a direction substantially perpendicular to the interface K (the arrow direction in the figure). Therefore, when the interface K is a substantially horizontal flat surface, the dislocation j may be an axial dislocation extending from the interface K to the shoulder portion and the straight body portion of the silicon single crystal in the growth direction of the silicon single crystal.
- the shape of the interface between the silicon single crystal and the silicon melt 3 varies depending on the pulling speed of the silicon single crystal, that is, the rising speed of the pulling shaft 4. Therefore, it is considered that the rising speed of the lifting shaft 4 is changed to change the shape of the flat interface K substantially parallel to the horizontal plane shown in FIG.
- the interface K1 between the silicon single crystal and the silicon melt 3 changes to a downwardly convex shape as shown in FIG.
- the interface K2 between the silicon single crystal and the silicon melt 3 changes to an upwardly convex shape as shown in FIG. That is, by controlling the pulling rate of the silicon single crystal, the shapes of the interfaces K1, K2 between the silicon single crystal and the silicon melt 3 can be controlled.
- the silicon single crystal grows in a direction perpendicular to the interfaces K1 and K2. Further, the dislocation j progresses in the direction in which the silicon single crystal grows. That is, the dislocation j progresses in the normal direction of a virtual tangent plane between the interfaces K1 and K2 between the silicon single crystal and the silicon melt 3. Therefore, as shown in FIG. 16B, when the interface K1 is a downwardly convex curved surface, most of the dislocations j progress outward in the radial direction of the dislocation-free portion N of the silicon single crystal. As shown in FIG. 16C, when the interface K2 is an upwardly convex curved surface, most of the dislocations j progress toward the radially inner side of the dislocation-free portion N of the silicon single crystal.
- the direction in which the dislocation j advances can be moved in a direction different from the direction of the central axis, which is the growth direction of the silicon single crystal. . That is, at an arbitrary point on the interface K1, K2, the dislocation j advances in the normal direction of the virtual tangent plane at a point where the virtual tangent plane is not horizontal. Therefore, at an arbitrary point on the interfaces K1 and K2, the direction in which the dislocation j advances is different from the direction of the central axis, which is the growth direction of the silicon single crystal, in that the virtual tangent plane is not horizontal. To do. Thereby, the heat shock dislocation Jn and the misfit dislocation Jm that do not exist in the ⁇ 111 ⁇ plane can be moved to the ⁇ 111 ⁇ plane and removed.
- the dislocation j advances toward the outer side in the radial direction of the dislocation-free portion N of the silicon single crystal and reaches the outer peripheral surface of the silicon single crystal, thereby dislocation-free. Part N is removed.
- the interface K2 is an upwardly convex curved surface
- the dislocation j progresses inward in the radial direction of the dislocation-free portion N of the silicon single crystal and is eliminated at the dislocation-free portion N by annihilating the pair. The Therefore, the dislocation j extending from an arbitrary point on the interfaces K1, K2 whose virtual tangent plane is not horizontal can be removed, and the occurrence of the axial dislocation J can be prevented.
- the dislocation j is advanced toward the central axis of the silicon single crystal to be annihilated, or is advanced toward the outer peripheral surface of the silicon single crystal and removed, the dislocation j is formed when the pulling speed of the silicon single crystal fluctuates.
- the diameter of the silicon single crystal may vary. At this time, even if the diameter of the silicon single crystal is reduced to some extent, there is no problem as long as the diameter of the silicon single crystal finally formed can be held. Even if the diameter of the silicon single crystal is increased to some extent, there is no problem as long as the raw material is not wasted. Therefore, the diameter of the silicon single crystal may vary to some extent as long as the pulling of the straight body portion of the silicon single crystal is not adversely affected. Due to the change in pulling speed, the direction in which dislocations progress may deviate from the pulling direction of the silicon single crystal. This phenomenon is preferable for dislocation removal.
- the interfaces K1 and K2 shown in FIGS. 16A and 16B are curved surfaces with a central axis parallel to the growth direction of the silicon single crystal. That is, the interfaces K1 and K2 are rotationally symmetric curved surfaces when the central axis of the silicon single crystal is the rotation axis. Therefore, the imaginary tangent plane at the intersection of the interfaces K1, K2 and the central axis of the silicon single crystal may be horizontal.
- the dislocation j generated on the central axis of the silicon single crystal advances in the growth direction of the silicon single crystal on the central axis of the silicon single crystal.
- This dislocation j may be an axial dislocation extending from the interfaces K1 and K2 to the shoulder portion and the straight body portion of the silicon single crystal.
- step S03 of the present embodiment as shown in FIGS. 17A and 17B, the interfaces K3 and K4 between the silicon single crystal and the silicon melt 3 are curved, and silicon It is deformed into an asymmetric shape with respect to the central axis of the single crystal. Specifically, a temperature distribution in the direction perpendicular to the central axis of the silicon single crystal, that is, the radial direction is generated at the interfaces K3 and K4.
- the interfaces K1 and K2 are curved surfaces symmetrical with respect to the central axis parallel to the growth direction of the silicon single crystal.
- the dislocation-free portion N of the silicon single crystal is heated or cooled from one direction, so that the interface K1, K2 has the center axis direction of the silicon single crystal.
- a temperature distribution perpendicular to is generated.
- the vicinity of the interfaces K1, K2 of the dislocation-free portion N is heated from one direction by irradiating laser light from the laser irradiation portion La. Further, the cooling gas is supplied from the side opposite to the laser irradiation unit La by the gas supply unit G. Thereby, the vicinity of the interfaces K1, K2 of the dislocation-free portion N is cooled from the direction opposite to the direction in which the dislocation-free portion N is heated.
- the radiant heat of the heater 2 and the silicon melt 3 reaches the vicinity of the interfaces K1 and K2 of the non-dislocation portion N from the notch 7A of the heat shielding portion 7 so that no dislocation occurs.
- Part N is heated from one direction. In this way, a temperature gradient perpendicular to the rising direction of the lifting shaft 4 is generated at the interfaces K1 and K2.
- the interfaces K3 and K4 between the dislocation-free portion N of the silicon single crystal and the silicon melt 3 are parallel to the growth direction of the silicon single crystal.
- the horizontal portion Kd of the interfaces K3 and K4 moves to a position away from the portion Kc on the central axis of the silicon single crystal outward in the radial direction.
- the shapes of the interfaces K3 and K4 between the silicon single crystal and the silicon melt 3 are such that the strength of the magnetic field generated by the magnetic field generator 9, the rotational speed of the crucible 1, and the rotational speed of the silicon single crystal, that is, the pulling shaft 4 It also changes depending on the rotation speed. Therefore, by controlling these, the shapes of the interfaces K3 and K4 between the silicon single crystal and the silicon melt 3 are more precisely controlled, and the position of the horizontal portion Kd is more precisely controlled.
- the rotational speed of the crucible 1 and the rotational speed of the pulling shaft 4 may be controlled so that the silicon melt 3 and the silicon single crystal are relatively stationary.
- the convection of the silicon melt 3 is not symmetric with respect to the central axis of the silicon single crystal, and the growth of the silicon single crystal is not symmetric with respect to the central axis of the silicon single crystal. That is, the temperature distribution at the interfaces K3 and K4 between the silicon single crystal and the silicon melt 3 is not symmetrical with respect to the central axis of the silicon single crystal.
- the horizontal portion Kd of the interfaces K3 and K4 moves to a position away from the portion Kc on the central axis of the silicon single crystal outward in the radial direction.
- the strength of the magnetic field generated by the magnetic field generator 9 may be reduced to reduce the strength of the magnetic field to zero.
- the convection of the silicon melt 3 is rectified by a magnetic field. For this reason, if the magnetic field is extinguished during the pulling of the silicon single crystal, the convection of the silicon melt 3 fluctuates. Thereby, the convection of the silicon melt 3 is not symmetric with respect to the central axis of the silicon single crystal, and the growth of the silicon single crystal is not symmetric with respect to the central axis of the silicon single crystal. That is, the temperature distribution at the interfaces K3 and K4 between the silicon single crystal and the silicon melt 3 is not symmetrical with respect to the central axis of the silicon single crystal. As a result, the horizontal portion Kd of the interfaces K3 and K4 moves to a position away from the portion Kc on the central axis of the silicon single crystal outward in the radial direction.
- the heater 2 may be rotated in synchronization with the rotation of the lifting shaft 4 in a state where the heater 2 is disposed asymmetrically on the lifting shaft 4.
- the convection of the silicon melt 3 is not symmetrical with respect to the central axis of the silicon single crystal, and the temperature distribution of the silicon melt 3 is not subject to the central axis of the silicon single crystal.
- the growth of the silicon single crystal is not symmetrical with respect to the central axis of the silicon single crystal. That is, the temperature distribution at the interfaces K3 and K4 between the silicon single crystal and the silicon melt 3 is not symmetrical with respect to the central axis of the silicon single crystal.
- the horizontal portion Kd of the interfaces K3 and K4 moves to a position away from the portion Kc on the central axis of the silicon single crystal outward in the radial direction.
- the properties of a part of the inner peripheral surface of the quartz crucible 1a may be made different from the properties of other parts. Specifically, a portion of about one quarter of the entire circumference of the inner peripheral surface within a range of about 10 cm from the upper end of the quartz crucible 1a may be a modified portion different from the other portions. In this case, in the altered portion, the bubble content at a position where the depth from the surface is within the range of 0.5 mm to 1 mm is within the range of 25% to 35% than the bubble content of other portions. Do more. For example, the bubble content rate in the altered portion may be increased by 30% from the bubble content rate in other portions.
- the convection of the silicon melt 3 is not symmetrical with respect to the central axis of the silicon single crystal, and the silicon single crystal Crystal growth is no longer symmetrical about the central axis of the silicon single crystal. That is, the temperature distribution at the interfaces K3 and K4 between the silicon single crystal and the silicon melt 3 is not symmetrical with respect to the central axis of the silicon single crystal. As a result, the horizontal portion Kd of the interfaces K3 and K4 moves to a position away from the portion Kc on the central axis of the silicon single crystal outward in the radial direction.
- the horizontal portion Kd of the interfaces K3 and K4 can be moved as appropriate.
- the heat shock dislocation Jn and the misfit dislocation Jm that do not exist in the ⁇ 111 ⁇ plane can be reliably moved to the ⁇ 111 ⁇ plane and removed in the dislocation-free portion N. Therefore, the dislocation j extending from any point on the interfaces K3 and K4 can be reliably removed, and the axial dislocation J can be more reliably removed.
- the axial dislocation extending to the straight body portion that could not be removed by the conventional method It is possible to produce a silicon single crystal that does not exist.
- a wafer having no axial dislocations can be manufactured from the straight body portion of the silicon single crystal in which no axial dislocations exist.
- Step S00 to S06 and Steps S11 to S13 were performed. Specifically, as shown in Table 2, the pulling speed of the pulling shaft, the distance (height) from the heat shield and the liquid surface of the silicon melt, and the seed crystal are immersed and held in the silicon melt. Five combinations with different retention times were used.
- step S13 shown in FIG. 2 the state of each sample was observed.
- sample 1 as shown in FIG. 8A, dislocations extend in the axial direction, and dislocations are not removed.
- Sample 4 as shown in FIG. 8B, dislocations are present, but the dislocations are annihilated in a loop shape, and the dislocations are removed.
- sample 5 dislocations are removed as shown in FIG. Therefore, as the pulling conditions in step S00, the pulling speed of the pulling shaft is in the range from 0.5 mm / min to 1.5 mm / min, and the distance (height) from the silicon melt is in the range of 100 mm to 150 mm. The holding time is set to 100 min. As a result, dislocations at the dislocation-free portion were removed, and dislocations at the shoulder portion and the straight body portion of the silicon single crystal could be removed.
- the method for producing a silicon single crystal of the present invention includes the following steps. A step of growing a silicon single crystal by bringing the seed crystal into contact with the silicon melt and then pulling it up. A step of forming dislocation-free portions in the silicon single crystal by causing dislocations generated in the silicon single crystal to be removed by extending outward in the radial direction of the silicon single crystal or eliminating them in a loop; A step of pulling up the silicon single crystal on which the dislocation-free portion is formed and expanding it to a predetermined diameter to form a straight body portion;
- the method for producing a silicon single crystal of the present invention solves at least one of the following problems. Dislocations generated in the process of bringing the seed crystal into contact with the silicon melt are removed to realize dislocation-free. To accurately grasp the occurrence and removal of dislocations. To accurately grasp the relationship between the state of dislocations at the neck and the conditions for pulling up the silicon single crystal. To accurately determine the pulling conditions for silicon single crystals that can be dislocation-free.
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Abstract
Description
本願は、2009年6月18日に、日本に出願された特願2009-145248号、及び、2009年6月19日に、日本に出願された特願2009-146995号に基づき優先権を主張し、その内容をここに援用する。 The present invention relates to a technique suitable for use in a method and apparatus for producing a silicon single crystal.
This application claims priority based on Japanese Patent Application No. 2009-145248 filed in Japan on June 18, 2009, and Japanese Patent Application No. 2009-14695 filed on June 19, 2009 in Japan. And the contents thereof are incorporated herein.
あるいは、特許文献5に示すように肩形状の手前に径が拡大した径大部を作成し、その径大部を把持して結晶を保持する方法がある。 Moreover, when pulling up a large single crystal, the introduction of dislocation during landing is suppressed so as not to give a heat shock. Techniques similar to these are described in
Alternatively, as shown in
また、特許文献5に記載されたような可動部を炉内に設けた場合、この可動部が汚染源となり、結果的にシリコン単結晶引き上げには実用できないという問題があった。 Further, as described in
Further, when a movable part as described in
1.シード融液接触工程で発生する転位を確実に除去して無転位化を実現すること。
2.転位、特に軸状転位についての発生および除去の状態を正確に捉えること。
3.ネック部での転位の振る舞いと引き上げ条件との関係を正確に把握すること。
4.無転位化可能な引き上げ条件を正確に決定すること。 The present invention has been made in view of the above circumstances, and achieves the following objects.
1. Dislocations generated in the seed melt contact process are surely removed to achieve dislocation-free.
2. Accurately capture the state of occurrence and removal of dislocations, especially axial dislocations.
3. To accurately grasp the relationship between dislocation behavior at the neck and the lifting conditions.
4). Accurately determine lifting conditions that can eliminate dislocations.
つまり、上述した軸状転位とは、このような手法により本願発明者らが初めてその存在を明らかにした。軸状転位は、シリコン単結晶の直胴部、および、これをスライスしたウェーハにおいて、ピットとして観測されていた。しかし、観測されたピットが軸状転位であるとの認識はされていなかった。 However, when white X-rays are used as high-energy radiation at the level described in
That is, the present inventors have revealed the existence of the above-described axial dislocation for the first time by such a technique. Axial dislocations were observed as pits in the straight body of a silicon single crystal and a sliced wafer. However, it was not recognized that the observed pits were axial dislocations.
まず、ウェーハがスライスされたシリコン単結晶は、晶癖線がきちんと形成されるとともに無転位化(Dislocation free)が実現できており、他の検査によっても単結晶であると認識されている。このようなウェーハ表面において、光学的な検査手段を使用した歪み測定をおこなうことで軸状転位を識別することができる。このような検査手段として、内部応力の分布状態を目視により観察することができるJENAWAVE社製歪み検査装置(SIRD;登録商標)SirTecを用いることができる。 This axial dislocation can be clearly detected from the other pits on the wafer by the following method.
First, a silicon single crystal obtained by slicing a wafer has a crystal habit line properly formed and can realize dislocation free, and is recognized as a single crystal by other inspections. On such a wafer surface, axial dislocations can be identified by performing strain measurement using an optical inspection means. As such an inspection means, a strain inspection apparatus (SIRD; registered trademark) SirTec manufactured by JENAWAVE, which can visually observe the internal stress distribution state, can be used.
このため、軸状転位は上記の顕在化処理によって顕在化されるが、他のピットなどはこの顕在化処理によっては顕在化されない。顕在化した軸状転位を有するウェーハの観測例と、軸状転位のないウェーハの観測例とを図11に示す。
図11の(a)に示す観測例は、3個の軸状転位が発生した例であり、図11の(b)に示す観測例は、軸状転位が発生しなかった例である。なお、ウェーハの縁に観測される歪みは、熱処理時のウェーハの支持によって発生したものと考えられる。 Since the axial dislocation exists through the front and back surfaces of the wafer, as described above, distortion due to the thermal stress generated by the manifestation process, which is rapid heating for an extremely short time, increases. On the other hand, in surface contamination inspection using a laser surface inspection machine, dislocations that are detected as pits in the same way as axial dislocations but not long enough to penetrate the front and back surfaces of the wafers were generated by the manifestation process. It is considered that the strain due to thermal stress does not increase. In other words, dislocations whose dimensions are less than about 10% of the thickness of the wafer are considered not to increase the strain due to the thermal stress generated by the manifestation process.
For this reason, axial dislocations are manifested by the above-described manifestation process, but other pits and the like are not manifested by this manifestation process. FIG. 11 shows an observation example of a wafer having a manifested axial dislocation and an observation example of a wafer having no axial dislocation.
The observation example shown in FIG. 11A is an example in which three axial dislocations have occurred, and the observation example shown in FIG. 11B is an example in which no axial dislocation has occurred. In addition, it is thought that the distortion observed at the edge of the wafer is caused by the support of the wafer during the heat treatment.
種結晶T付近を拡大すると、図13に示すように、縮径部(ネック部)N0には、熱ショック転位Jnおよびミスフィット転位Jmが発生する。熱ショック転位Jnは、種結晶Tをシリコン融液に接触させた際の熱ショックで種結晶T側に発生し、成長するシリコン単結晶60のネック部N0側に引き継がれる。ミスフィット転位Jmは、種結晶Tとシリコン単結晶60のネック部N0に格子定数の不整合がある場合に発生する。 As shown in FIG. 12, the silicon
When the vicinity of the seed crystal T is enlarged, as shown in FIG. 13, heat shock dislocations Jn and misfit dislocations Jm are generated in the reduced diameter portion (neck portion) N0. The heat shock dislocation Jn is generated on the seed crystal T side by the heat shock when the seed crystal T is brought into contact with the silicon melt, and is taken over to the neck portion N0 side of the growing silicon
ここで、回折像を観察するために用いる2次元検出器として、以下が挙げられる。蛍光板、X線フィルム、原子核乾板、輝尽性蛍光体(BaFBr:Eu2+)の光輝尽発光現象を利用したイメージングプレート。X線に感度のあるPbO膜やアモルファスSe-As膜を光導電面とした撮像管を用いたX線テレビ。電荷結合素子CCDを用いたCCD型X線検出器。本発明において用いるX線検出器としては、空間分解能やダイナミックレンジとして、次のような特性を考慮することが好ましい。 X-ray topography is also called X-ray diffraction microscopy, and is a method for observing the spatial distribution of defects in a non-destructive manner. When X-rays are continuously incident on the silicon single crystal, a plurality of diffraction images called diffraction spots are observed. X-ray topography analyzes this diffraction spot.
Here, the following is mentioned as a two-dimensional detector used in order to observe a diffraction image. An imaging plate that utilizes the photoluminescent phenomenon of a fluorescent plate, X-ray film, nuclear dry plate, and photostimulable phosphor (BaFBr: Eu 2+ ). An X-ray television using an imaging tube having a PbO film sensitive to X-rays or an amorphous Se-As film as a photoconductive surface. CCD type X-ray detector using a charge coupled device CCD. As the X-ray detector used in the present invention, it is preferable to consider the following characteristics in terms of spatial resolution and dynamic range.
ダイナミックレンジ
強度の直線性領域
不感時間と数え落とし
受光面積と位置分解能
感度の不均一性
位置の非直線性(または像ひずみ)
エネルギー分解能
時間分解能
実時間測定の能力
動作の安定性 Detection quantum efficiency Dynamic range intensity linearity area dead time and counting light receiving area and position resolution Sensitivity nonuniformity Nonlinearity (or image distortion) of position
Energy resolution Time resolution Real-time measurement capability Operational stability
1) 大前提として、転位はすべり面(シリコンの場合は{111}面)を移動する。
2) 通常{111}に転位は導入される。
3) まれに{111}に導入されずに他の面を移動する場合がある。また、その場合も、通常、すぐに{111}に移り変わる。
4) CZ法により製造するシリコン単結晶に導入される転位のほとんどは、種結晶をシリコン融液に接触させた時に発生する。 It has been found that the behavior of the heat shock dislocation Jn and the misfit dislocation Jm has the following characteristics. Here, the behavior of the heat shock dislocation Jn and the misfit dislocation Jm refers to the propagation direction in the process of growing a silicon single crystal that pulls up the neck portion, the shoulder portion, and the straight body portion.
1) As a major premise, dislocations move on the slip plane ({111} plane in the case of silicon).
2) Usually, dislocations are introduced at {111}.
3) In rare cases, other planes may be moved without being introduced at {111}. Also in that case, it is usually immediately changed to {111}.
4) Most of the dislocations introduced into the silicon single crystal produced by the CZ method occur when the seed crystal is brought into contact with the silicon melt.
また、シリコン単結晶の成長方向に伸びた転位が、シリコン単結晶の直径を増加させている途中、あるいは、直径が製品の直径に到達し、製品となる部位を製造中に{111}へ移動し、軸状転位となる場合もある。 The axial dislocation does not reach the surface of the silicon single crystal even if the diameter of the silicon single crystal is subsequently increased to the diameter of the product. Such a silicon single crystal having axial dislocations has a habit line similar to a silicon single crystal having no axial dislocations, and may not be distinguished from non-defective products in an ingot state. When the wafer sliced from the ingot is inspected, the axial dislocation is detected as a defect.
Also, dislocations extending in the growth direction of the silicon single crystal increase the diameter of the silicon single crystal, or the diameter reaches the product diameter, and the product part moves to {111} during manufacturing. In some cases, axial dislocations may occur.
1) シリコン単結晶は、シリコン単結晶とシリコン融液との界面である結晶育成面に垂直に成長する。そのため、ネック部を形成する時に発生して導入された転位は{111}でなく、結晶育成面に垂直な方向に移動する場合がある。
2) したがって、本発明は、{111}に存在しない転位をネック部を形成する段階で{111}に移動させるための方法である。この方法は、ネック部の形成時のシリコン単結晶とシリコン融液との界面の形状を変化させる手段を採用する。その条件確認で放射光設備におけるX線トポグラフィを用いる。 The inventors of the present application focused on the following points.
1) A silicon single crystal grows perpendicularly to a crystal growth surface which is an interface between the silicon single crystal and the silicon melt. For this reason, dislocations that are generated and introduced when the neck portion is formed are not {111} but may move in a direction perpendicular to the crystal growth surface.
2) Accordingly, the present invention is a method for moving dislocations that do not exist in {111} to {111} at the stage of forming the neck portion. This method employs means for changing the shape of the interface between the silicon single crystal and the silicon melt when the neck portion is formed. X-ray topography in synchrotron radiation equipment is used for checking the conditions.
前記除去困難転位除去工程において、除去困難転位の伸展方向を結晶成長方向から移動させてもよい。
前記除去困難転位除去工程において、除去困難転位を結晶引き上げに従って外部方向へ伸展させるかループ状に対消滅させて除去してもよい。
前記除去困難転位除去工程において、シリコン融液とシリコン単結晶との固液界面形状を融液表面から変形させて除去困難転位の伸展方向を結晶成長方向から移動させてもよい。
前記除去困難転位除去工程において、シリコン融液とシリコン単結晶との固液界面の接平面が融液表面と平行となる部分を中心位置から変動させて除去困難転位の伸展方向を結晶成長方向から移動させてもよい。
前記除去困難転位除去工程において、シリコン融液とシリコン単結晶との固液界面状態の揺らぎを増大して除去困難転位の伸展方向を結晶成長方向から移動させてもよい。
前記除去困難転位除去工程において、シリコン融液に対するシリコン単結晶の回転を低減して前記固液界面状態の揺らぎを増大してもよい。
前記除去困難転位除去工程において、シリコン融液に印加する磁場強度を低減して前記固液界面状態の揺らぎを増大してもよい。
前記除去困難転位除去工程において、シリコン融液を貯留する石英ガラスルツボに起因して発生する湯面振動により前記固液界面状態の揺らぎを増大してもよい。
前記除去困難転位除去工程において、シリコン単結晶を成長軸に対して非対称に加熱して前記固液界面状態の揺らぎを増大してもよい。
前記除去困難転位除去工程において、シリコン融液とシリコン単結晶との固液界面を成長軸に対して非対称になるように温度分布を形成して除去困難転位の伸展方向を結晶成長方向から移動させてもよい。
前記除去困難転位除去工程において、シリコン単結晶を成長軸に対して非対称に加熱して前記固液界面を成長軸に対して非対称にしてもよい。
本発明のシリコン単結晶の製造方法は、前記除去困難転位除去工程において、前記ディップ工程で発生した転位を結晶引き上げに従って外部方向へ伸展させるかループ状に対消滅させて除去する転位除去部を形成するとともに、以下の工程を有する。前記除去困難転位除去工程後に必要な直胴部径寸法まで拡径するショルダー部を引き上げる拡径工程。前記転位除去部に高エネルギー放射光を照射して該転位除去部内における転位の3次元的挙動である転位挙動情報を検出する転位挙動情報取得工程。前記転位挙動情報に基づいて、転位が除去されていることを判断する無転位化判断工程。前記無転位化判断工程における無転位化の判断に基づいて、無転位化実施引き上げ条件を決定する引き上げ条件設定工程。
本発明のシリコン単結晶の製造方法は、前記除去困難転位除去工程において、前記ディップ工程で発生した転位を結晶引き上げに従って外部方向へ伸展させるかループ状に対消滅させて除去する転位除去部を形成するとともに、以下の工程を有する。前記除去困難転位除去工程後に必要な直胴部径寸法まで拡径するショルダー部を引き上げる拡径工程。前記転位除去部に高エネルギー放射光を照射して該転位除去部内における転位の3次元的挙動である転位挙動情報を検出する転位挙動情報取得工程。前記転位挙動情報に基づいて、転位が除去されていることを判断する無転位化判断工程。そして、前記無転位化判断工程における無転位化の判断に基づいて、前記拡径工程を開始する。
上記のシリコン単結晶製造方法において、前記高エネルギー放射光が、40keV~70keVのエネルギーとされ、回転数0.1~30rpmで回転状態として転位除去部に照射されてもよい。
本発明のシリコン単結晶は、上記のいずれか記載の製造方法により製造される。
本発明のシリコンウェーハは、上記のシリコン単結晶から製造される。 The method for producing a silicon single crystal according to the present invention includes the following steps in the method for producing a silicon single crystal in which the silicon single crystal is pulled by the CZ method. A dipping process in which the seed crystal is brought into contact with the silicon melt to start pulling. A straight body process that pulls up the single crystal straight body that becomes a silicon wafer. A difficult-to-remove dislocation removal step of removing difficult-to-remove dislocations generated in the dip step before the straight body step. By having these steps, the above problems were solved.
In the difficult removal dislocation removal step, the extension direction of the difficult removal dislocation may be moved from the crystal growth direction.
In the difficult-to-remove dislocation removal step, the difficult-to-remove dislocations may be removed by extending outwardly according to crystal pulling or by annihilating them in a loop shape.
In the difficult-to-remove dislocation removal step, the solid-liquid interface shape between the silicon melt and the silicon single crystal may be deformed from the melt surface to move the extension direction of the difficult-to-remove dislocation from the crystal growth direction.
In the difficult-to-removal dislocation removal step, the extension direction of the difficult-to-removal dislocations is changed from the crystal growth direction by changing from the central position the portion where the tangential plane of the solid-liquid interface between the silicon melt and the silicon single crystal is parallel to the melt surface. It may be moved.
In the difficult-to-removal dislocation removal step, fluctuation of the solid-liquid interface state between the silicon melt and the silicon single crystal may be increased to move the extension direction of the difficult-to-remove dislocation from the crystal growth direction.
In the difficult-to-remove dislocation removal step, the rotation of the silicon single crystal relative to the silicon melt may be reduced to increase the fluctuation of the solid-liquid interface state.
In the difficult-to-remove dislocation removal step, the magnetic field strength applied to the silicon melt may be reduced to increase the fluctuation of the solid-liquid interface state.
In the difficult-to-remove dislocation removal step, fluctuations in the solid-liquid interface state may be increased by molten-metal surface vibrations generated due to the quartz glass crucible storing the silicon melt.
In the difficult-to-remove dislocation removal step, the fluctuation of the solid-liquid interface state may be increased by heating the silicon single crystal asymmetrically with respect to the growth axis.
In the difficult removal dislocation removal step, a temperature distribution is formed so that the solid-liquid interface between the silicon melt and the silicon single crystal is asymmetric with respect to the growth axis, and the extension direction of the difficult removal dislocation is moved from the crystal growth direction. May be.
In the difficult-to-remove dislocation removal step, the silicon single crystal may be heated asymmetrically with respect to the growth axis so that the solid-liquid interface is asymmetric with respect to the growth axis.
The method for producing a silicon single crystal according to the present invention forms a dislocation removing portion that removes dislocations generated in the dipping step by extending the dislocations generated in the dip step in the outward direction or by annihilating them in a loop shape in the difficult removal dislocation removing step. In addition, the following steps are included. A diameter expansion step of pulling up a shoulder portion that expands to a necessary diameter of the straight body after the difficult removal dislocation removal step. A dislocation behavior information acquisition step of detecting dislocation behavior information that is a three-dimensional behavior of dislocations in the dislocation removal unit by irradiating the dislocation removal unit with high energy radiation. A dislocation-free determination step of determining that dislocations are removed based on the dislocation behavior information. A lifting condition setting step of determining a dislocation-free implementation raising condition based on the determination of dislocation-free in the non-dislocation determination step.
The method for producing a silicon single crystal according to the present invention forms a dislocation removing portion that removes dislocations generated in the dipping step by extending the dislocations generated in the dip step in the outward direction or by annihilating them in a loop shape in the difficult removal dislocation removing step. In addition, the following steps are included. A diameter expansion step of pulling up a shoulder portion that expands to a necessary diameter of the straight body after the difficult removal dislocation removal step. A dislocation behavior information acquisition step of detecting dislocation behavior information that is a three-dimensional behavior of dislocations in the dislocation removal unit by irradiating the dislocation removal unit with high energy radiation. A dislocation-free determination step of determining that dislocations are removed based on the dislocation behavior information. And based on the determination of non-dislocation in the non-dislocation determination step, the diameter expansion step is started.
In the above-described silicon single crystal manufacturing method, the high-energy radiation light may be 40 keV to 70 keV energy and may be irradiated to the dislocation removing unit as a rotation state at a rotation speed of 0.1 to 30 rpm.
The silicon single crystal of the present invention is produced by any one of the production methods described above.
The silicon wafer of the present invention is manufactured from the above silicon single crystal.
転位の伸展は、すべり面である{111}でなく、まず結晶育成面に垂直に結晶が成長するためにその方向に移動する。つまり、図16の(a)に示すように、シリコン融液3と成長単結晶6との間の固液界面Kにおいて、転位jを接点とする接平面の法線方向に伸展する。固液界面Kが液面30と平行、つまり、固液界面Kが平面状態の場合、図16の(a)に示すように、転位jは融液3中に矢印で示す方向に伸展していく。従って、図に上下方向で示す軸方向(結晶成長方向)の転位jは結晶成長方向へ伸展する。転位jがこのまま結晶成長方向へ伸展すると、転位jの位置はシリコン単結晶の拡径部で径方向に変化するが、消去されることはない。したがって、結晶成長方向へ伸展する転位jは、直胴部においても結晶成長方向へ延びるように存在する軸状転位になることがある。 In the difficult-to-remove dislocation removal step, the solid-liquid interface shape between the silicon melt and the silicon single crystal can be deformed from the melt surface to move the extension direction of the difficult-to-remove dislocation from the crystal growth direction.
The dislocation extension is not {111}, which is a slip plane, but first moves in that direction because the crystal grows perpendicular to the crystal growth plane. That is, as shown in FIG. 16A, the solid-liquid interface K between the
これによって、転位jは、結晶引き上げに従って、図16の(b)に示すように、固液界面K1において、転位jを接点とする接平面の法線方向に伸展する。また、転位jは、結晶引き上げに従って、図16の(c)に示すように、固液界面K2において、転位jを接点とする接平面の法線方向に伸展する。
したがって、転位jは、結晶引き上げに従って、図16の(b)に示すように、それぞれシリコン単結晶の外部方向へ伸展する。または、図16の(c)に示すように、複数の転位jがシリコン単結晶の中心軸方向に集まる。この結果、転位jをシリコン単結晶の外部に抜けさせるか、または他の転位と対消滅させて除去することが可能となる。したがって、転位jが軸状転位すなわち除去困難転位となることを防止できる。 The deformation of the solid-liquid interface shape between the silicon melt and the silicon single crystal from the surface of the melt means that the solid state between the
As a result, the dislocation j extends in the normal direction of the tangential plane with the dislocation j as a contact at the solid-liquid interface K1, as shown in FIG. Further, as shown in FIG. 16C, the dislocation j extends in the normal direction of the tangential plane with the dislocation j as a contact at the solid-liquid interface K2 as the crystal is pulled.
Therefore, the dislocations j extend toward the outside of the silicon single crystal as shown in FIG. Alternatively, as shown in FIG. 16C, a plurality of dislocations j gather in the direction of the central axis of the silicon single crystal. As a result, the dislocation j can be removed outside the silicon single crystal, or can be eliminated by annihilation with other dislocations. Therefore, the dislocation j can be prevented from becoming an axial dislocation, that is, a dislocation that is difficult to remove.
(a)界面形状がフラットの時 転位は垂直方向(シリコン単結晶の中心軸方向、鉛直方向)に伸展
(b)界面形状が下方に凸の時 転位はシリコン単結晶の外周に向かって伸展
(c)界面形状が上方に凸の時 転位はシリコン単結晶の内部に向かって伸展 The relationship between the solid-liquid interface shape and the direction of dislocation propagation can be summarized as follows.
(A) When the interface shape is flat, the dislocation extends in the vertical direction (the central axis direction of the silicon single crystal, the vertical direction). (B) When the interface shape protrudes downward, the dislocation extends toward the outer periphery of the silicon single crystal ( c) When the interface shape is convex upward, the dislocation extends toward the inside of the silicon single crystal.
また、引き上げ速度の変化により、結晶の直径が変動することがある。転位を除去して軸状転位の発生を防止するために、引き上げ速度を小さくした際、転位が結晶の外部方向へ抜けて除去でき、軸状転位の発生が防止できる。この場合、引き上げる結晶の保持が可能である程度に直径が小さくなることは問題ない。また、引き上げ速度を大きくした際、転位が中心方向へ向かい対消滅して除去できるかそのまま外部へ抜けて除去でき、軸状転位の発生が防止できる。この場合、原料をムダにしない程度に拡径することは問題がない。そのため、シリコン単結晶の直胴部の引き上げへの影響がなければ、結晶の直径の変動の範囲は特に限定されない。
また、引き上げ速度の変化によって、シリコン単結晶の引き上げ方向(軸方向)から転位の伸張方向がずれることも、転位を除去するためには好ましい。 These solid-liquid interface shapes can be controlled by the pulling speed. That is, when the pulling speed is increased, the shape of the interface becomes convex upward. Further, when the pulling speed is reduced, the shape of the interface becomes convex downward. In addition, more precise control can be performed by changing the magnitude of the magnetic field to be applied, the rotational speed of the crucible, the rotational speed of the crystal, and the like.
In addition, the diameter of the crystal may vary due to a change in the pulling speed. When the pulling rate is reduced in order to remove dislocations and prevent the occurrence of axial dislocations, the dislocations can be removed in the outward direction of the crystal, and the occurrence of axial dislocations can be prevented. In this case, there is no problem that the diameter is reduced to a certain extent so that the crystal to be pulled can be held. Further, when the pulling speed is increased, the dislocations can be eliminated by disappearing toward the center, or they can be removed as they are, so that the occurrence of axial dislocations can be prevented. In this case, there is no problem in expanding the diameter so as not to waste the raw material. Therefore, the range of the crystal diameter variation is not particularly limited as long as it does not affect the pulling up of the straight body of the silicon single crystal.
In order to remove dislocations, it is also preferable that the dislocation extension direction shifts from the pulling direction (axial direction) of the silicon single crystal due to a change in pulling speed.
また、石英ガラスルツボの一部分、例えば内壁の周方向に四分の一程度の範囲の状態をそれ以外の部分と異ならせ、シリコン融液の湯面(液面)の振動の原因と考えられる突沸の発生率を高くしてもよい。具体的には、ルツボ上端から10cmの範囲内であり、周方向の1/4程度の範囲内の内壁において、表面から0.5mm~1mmの深さ(厚さ位置)における気泡含有率をそれ以外の範囲の部分の内壁の表面の気泡含有率より30%程度(25~35%)多くしてもよい。 In order to change the state of the silicon melt from a state suitable for crystal growth that is symmetric with respect to the central axis of the silicon single crystal, it is necessary to shift the heating of the quartz glass crucible storing the silicon melt from the symmetric state. Conceivable. For example, the heating position may be rotated following the rotating crucible.
In addition, a part of the quartz glass crucible, for example, a state in the range of about a quarter in the circumferential direction of the inner wall, is different from the other parts, and bumping that is considered to be the cause of the vibration of the silicon melt surface (liquid level) The occurrence rate may be increased. Specifically, the bubble content at a depth (thickness position) of 0.5 mm to 1 mm from the surface of the inner wall within a range of 10 cm from the upper end of the crucible and within a range of about ¼ of the circumferential direction. It may be about 30% (25 to 35%) higher than the bubble content on the surface of the inner wall in the range other than the above.
前記除去困難転位除去工程後に必要な直胴部径寸法まで拡径するショルダー部を引き上げる拡径工程。前記転位除去部に高エネルギー放射光を照射して該転位除去部内における転位の3次元的挙動である転位挙動情報を検出する転位挙動情報取得工程。前記転位挙動情報に基づいて、転位が除去されていることを判断する無転位化判断工程。前記無転位化判断工程における無転位化の判断に基づいて、無転位化実施引き上げ条件を決定する引き上げ条件設定工程。
これにより、従来その挙動が解明されていなかった転位の振る舞いを明らかにすることができる。また、この転位を転位除去部(無転位化部)の成長に伴って外方へ抜けるように消滅させることができる。あるいは、転位をループとして消滅させ、無転位化した上で、シリコン単結晶の直径を拡大する引き上げ条件を容易に求めることができる。 The method for producing a silicon single crystal according to the present invention forms a dislocation removing portion that removes dislocations generated in the dipping step by extending the dislocations generated in the dip step in the outward direction or by annihilating them in a loop shape in the difficult removal dislocation removing step. In addition, the following steps are included.
A diameter expansion step of pulling up a shoulder portion that expands to a necessary diameter of the straight body after the difficult removal dislocation removal step. A dislocation behavior information acquisition step of detecting dislocation behavior information that is a three-dimensional behavior of dislocations in the dislocation removal unit by irradiating the dislocation removal unit with high energy radiation. A dislocation-free determination step of determining that dislocations are removed based on the dislocation behavior information. A lifting condition setting step of determining a dislocation-free implementation raising condition based on the determination of dislocation-free in the non-dislocation determination step.
This makes it possible to clarify the behavior of dislocations whose behavior has not been clarified. Further, this dislocation can be eliminated so as to escape outward along with the growth of the dislocation removal portion (dislocation-free portion). Alternatively, it is possible to easily obtain a pulling condition for expanding the diameter of the silicon single crystal after eliminating the dislocation as a loop and eliminating the dislocation.
これにより、従来不可能であった非破壊検査によって引き上げ時に発生した転位の挙動をリアルタイムに観測することが可能となる。そのため、転位除去部(無転位化部)において転位が除去(無転位化)されたことを確認した後に、ショルダー部(拡径部)および直胴部の引き上げをおこなうことが可能となる。そのため、転位が除去され、軸状転位を有さない無転位結晶を安全かつ容易に引き上げることができる。 The method for producing a silicon single crystal according to the present invention forms a dislocation removing portion that removes dislocations generated in the dipping step by extending the dislocations generated in the dip step in the outward direction or by annihilating them in a loop shape in the difficult removal dislocation removing step. In addition, the following steps are included. A diameter expansion step of pulling up a shoulder portion that expands to a necessary diameter of the straight body after the difficult removal dislocation removal step. A dislocation behavior information acquisition step of detecting dislocation behavior information that is a three-dimensional behavior of dislocations in the dislocation removal unit by irradiating the dislocation removal unit with high energy radiation. A dislocation-free determination step of determining that dislocations are removed based on the dislocation behavior information. And based on the determination of non-dislocation in the non-dislocation determination step, the diameter expansion step is started.
As a result, it is possible to observe in real time the behavior of dislocations generated during pulling up by non-destructive inspection, which has been impossible in the past. Therefore, after confirming that the dislocations are removed (dislocation-free) in the dislocation removal portion (dislocation-free portion), the shoulder portion (expanded diameter portion) and the straight body portion can be pulled up. Therefore, dislocations are removed, and dislocation-free crystals having no axial dislocations can be pulled up safely and easily.
このようなエネルギーを有する高エネルギー放射光によって、無転位の結晶の育成に必要な転位の状態の情報を十分に取得することができる。
また、前記高エネルギー放射光が、回転数0.1~30rpmで回転状態として転位除去部に照射されてもよい。
これにより、転位の3次元情報を取得することができる。また非破壊で情報を取得可能とすることができる。
ここで、高エネルギー放射光が回転状態で照射されるとは、次のことを含む。転位除去部(無転位化部)が結晶成長方向の中心軸を回転中心軸として回転し、この無転位化部に高エネルギー放射光を照射すること。あるいは、高エネルギー放射光の照射源と無転位化部とが上記の回転に匹敵する相対運動状態で、転位の情報を取得するための高エネルギー放射光照射がおこなわれること。 In the silicon single crystal manufacturing method, the high-energy radiation light may have an energy of 40 keV to 70 keV.
With the high-energy synchrotron radiation having such energy, it is possible to sufficiently acquire information on the dislocation state necessary for growing a dislocation-free crystal.
Further, the dislocation removing unit may be irradiated with the high energy radiation light in a rotational state at a rotational speed of 0.1 to 30 rpm.
Thereby, the three-dimensional information of dislocation can be acquired. In addition, information can be acquired nondestructively.
Here, the irradiation with high energy radiation light in a rotating state includes the following. A dislocation removal part (dislocation-free part) rotates around the central axis in the crystal growth direction as a rotation center axis, and this dislocation-free part is irradiated with high energy radiation. Alternatively, irradiation with high energy synchrotron radiation for obtaining information on dislocation is performed in a relative motion state in which the irradiation source of high energy synchrotron radiation and the dislocation-free part are comparable to the above rotation.
このため、ディップ工程は、結晶の原料を融解して所定の時間経過した後に実施される。このとき、種結晶をシリコン融液に接触させた際の液面の温度が高すぎる場合には、種結晶の先端部が溶けて、溶融液から切り離されてしまう。逆に、シリコン融液の液面の温度が低すぎる場合には、種結晶の先端部の周囲に結晶が成長する。すると、融液の表面において結晶が種結晶の周囲に張り出した状態になる。このような状態でディップ工程からネック工程に移行すると、ネック部に新たな転位を生ずる。 Usually, when the seed crystal is brought into contact with the silicon melt, a meniscus is formed at the interface due to the surface tension of the silicon melt. However, the temperature of the melt immediately after melting the crystal raw material has a large local temperature fluctuation. Further, the temperature of the melt as a whole is extremely large and unstable.
For this reason, the dipping process is performed after a predetermined time has elapsed after melting the crystal raw material. At this time, if the temperature of the liquid surface when the seed crystal is brought into contact with the silicon melt is too high, the tip of the seed crystal melts and is separated from the melt. Conversely, if the temperature of the silicon melt surface is too low, crystals grow around the tip of the seed crystal. Then, the crystal protrudes around the seed crystal on the surface of the melt. When shifting from the dip process to the neck process in such a state, new dislocations are generated in the neck part.
すなわち、種結晶とシリコン融液とをなじませることは、以下のことを含む。種結晶をシリコン融液に接触させた際のこれらの界面の形状を観察することでシリコン融液の表面(液面)の温度を推定すること。推定した液面の温度に基づいてヒータの電力を制御してシリコン融液への入熱量を調整すること。
言い換えると、種結晶とシリコン融液とをなじませることは、以下の操作を含む。種結晶の成長速度が0(ゼロ)の状態において、種結晶の先端部の周囲に所定形状のメニスカスが形成されるように、ヒーターパワーを調整して融液表面温度を調整し安定化させる操作。なお、メニスカスは種結晶とシリコン融液とをなじませる時だけに形成されるものではない。メニスカスは種結晶とシリコン融液とをなじませる工程に続くネック工程などの結晶の成長時にも結晶と融液との界面に形成される。 For this reason, when shifting from a dipping process to a neck process, it is necessary for the melt temperature to be stabilized. Therefore, after immersing the tip of the seed crystal in the silicon melt, fully blending the seed crystal and the silicon melt, and confirming that the temperature of the silicon melt has stabilized, the dipping process is followed by the neck process. Transition.
That is, conforming the seed crystal and the silicon melt includes the following. Estimate the temperature of the surface (liquid level) of the silicon melt by observing the shape of these interfaces when the seed crystal is brought into contact with the silicon melt. Control the heater power based on the estimated liquid surface temperature to adjust the heat input to the silicon melt.
In other words, conforming the seed crystal and the silicon melt includes the following operations. An operation for adjusting and stabilizing the melt surface temperature by adjusting the heater power so that a meniscus having a predetermined shape is formed around the tip of the seed crystal when the growth rate of the seed crystal is 0 (zero). . The meniscus is not formed only when the seed crystal and the silicon melt are mixed. The meniscus is also formed at the interface between the crystal and the melt during the growth of the crystal, such as a neck process following the process of allowing the seed crystal and the silicon melt to blend.
(2)MCZ法を用いる場合、まず、ルツボ内の結晶の原料を融解させ、種結晶をルツボ内に保持される溶融液に浸漬させて種結晶をなじませる。その後、種結晶を引き上げてネック部を形成するネック工程を実施する。次いで、単結晶のショルダー部およびボディー部を形成する。このような単結晶製造方法において、前記ネック工程で所定長さのネック部を形成した後、当該ネック部を溶融液になじませて、引き続きネック部を形成することがある。
MCZ法を適用する場合には、溶融液に印加する横磁場を2000G~4000Gの範囲で行ってもよい。
(3)上記(1)または(2)のシリコン単結晶の製造では、ネック工程において最初に形成されるネック部の長さを20mm以上にしてもよい。また、前記ネック工程において、ネック部を形成する際の溶融液の温度よりも高い温度に上昇させた後、当該ネック部を溶融液になじませるようにしてもよい。さらに、ルツボ内の結晶の原料を融解させるヒータの温度を計測(測温)して、当該測温の結果に基づきヒータの温度を制御して溶融液の温度を調整してもよい。 (1) In the case of using the CZ method, first, the raw material of the crystal in the crucible is melted, and the seed crystal is immersed in a melt held in the crucible to make the seed crystal conform. Then, the neck process which raises a seed crystal and forms a neck part is implemented. Next, a shoulder portion and a body portion of a single crystal are formed. In such a silicon single crystal manufacturing method, after the neck portion having a predetermined length is formed in the neck step, the neck portion may be made to conform to the melt and the neck portion may be subsequently formed.
(2) When using the MCZ method, first, the raw material of the crystal in the crucible is melted, and the seed crystal is immersed in a melt held in the crucible to make the seed crystal conform. Then, the neck process which raises a seed crystal and forms a neck part is implemented. Next, a shoulder portion and a body portion of a single crystal are formed. In such a single crystal manufacturing method, after the neck portion having a predetermined length is formed in the neck step, the neck portion may be continuously formed by fitting the neck portion into the melt.
When the MCZ method is applied, the transverse magnetic field applied to the melt may be performed in the range of 2000G to 4000G.
(3) In the manufacture of the silicon single crystal of the above (1) or (2), the length of the neck portion formed first in the neck step may be 20 mm or more. Further, in the neck step, after raising the temperature of the melt at the time of forming the neck portion, the neck portion may be adapted to the melt. Further, the temperature of the heater for melting the crystal raw material in the crucible may be measured (temperature measurement), and the temperature of the melt may be adjusted by controlling the temperature of the heater based on the temperature measurement result.
このように、種結晶及びネック部を溶融液になじませると、転位を除去し易くなる。しかし、種結晶及びネック部を溶融液になじませない場合でも、本願発明における上記の条件のいずれの製造方法においては、軸状転位のない直胴部を製造することが可能となる。 The above-mentioned adjustment of the seed crystal to the melt (silicon melt) and the conformation of the neck portion to the melt include the meniscus shape of the contact interface when the crystal is brought into contact with the melt, for example, Includes observing the overhang of crystal habit lines. That is, the temperature of the surface of the melt is estimated, the heater power (electric power) is controlled based on the temperature, the amount of heat input to the melt is adjusted, and the temperature of the surface of the melt is stabilized.
As described above, when the seed crystal and the neck portion are adapted to the melt, dislocations are easily removed. However, even when the seed crystal and the neck portion are not adapted to the melt, in any of the above manufacturing methods in the present invention, it is possible to manufacture a straight body portion having no axial dislocation.
本発明のシリコンウェーハは、上記のシリコン単結晶から製造される。 The silicon single crystal of the present invention is produced by any one of the production methods described above.
The silicon wafer of the present invention is manufactured from the above silicon single crystal.
本発明のシリコン単結晶の製造方法は、シリコン単結晶をCZ法により引き上げるシリコン単結晶の製造方法において、以下の工程を含む。シリコン融液に種結晶を接触し引き上げを開始するディップ工程。ディップ工程で発生した転位を結晶引き上げに従って外部方向へ伸展させるかループ状に対消滅させて除去する転位除去部を形成する転位除去工程。必要な径寸法まで拡径するショルダー部を引き上げる拡径工程。直胴部を引き上げる直胴工程。前記転位除去部に高エネルギー放射光を照射して該転位除去部内における転位の3次元的挙動である転位挙動情報を検出する転位挙動情報取得工程。前記転位挙動情報に基づいて、転位が除去されていることを判断する無転位化判断工程。
前記無転位化判断工程における無転位化の判断に基づいて、前記拡径工程を開始してもよい。
上記のシリコン単結晶製造方法において、前記高エネルギー放射光が、40keV~70keVのエネルギーとされ、回転数0.1~30rpmで回転状態として転位除去部に照射されてもよい。 The method for producing a silicon single crystal of the present invention includes the following steps in the method for producing a silicon single crystal in which the silicon single crystal is pulled up by the CZ method. A dipping process in which the seed crystal is brought into contact with the silicon melt to start pulling. A dislocation removing step for forming a dislocation removing portion that removes dislocations generated in the dip step by extending outwardly according to crystal pulling or by annihilating them in a loop shape. A diameter expansion process that raises the shoulder that expands to the required diameter. A straight body process that raises the straight body. A dislocation behavior information acquisition step of detecting dislocation behavior information that is a three-dimensional behavior of dislocations in the dislocation removal unit by irradiating the dislocation removal unit with high energy radiation. A dislocation-free determination step of determining that dislocations are removed based on the dislocation behavior information. A lifting condition setting step of determining a dislocation-free implementation raising condition based on the determination of dislocation-free in the non-dislocation determination step. This solved the above problem.
The method for producing a silicon single crystal of the present invention includes the following steps in the method for producing a silicon single crystal in which the silicon single crystal is pulled up by the CZ method. A dipping process in which the seed crystal is brought into contact with the silicon melt to start pulling. A dislocation removing step for forming a dislocation removing portion that removes dislocations generated in the dip step by extending outwardly according to crystal pulling or by annihilating them in a loop shape. A diameter expansion process that raises the shoulder that expands to the required diameter. A straight body process that raises the straight body. A dislocation behavior information acquisition step of detecting dislocation behavior information that is a three-dimensional behavior of dislocations in the dislocation removal unit by irradiating the dislocation removal unit with high energy radiation. A dislocation-free determination step of determining that dislocations are removed based on the dislocation behavior information.
The diameter expansion step may be started based on the determination of dislocation-free in the dislocation-free determination step.
In the above-described silicon single crystal manufacturing method, the high-energy radiation light may have an energy of 40 keV to 70 keV, and may be irradiated to the dislocation removing unit as a rotation state at a rotation speed of 0.1 to 30 rpm.
これにより、従来その挙動が解明されていなかった転位の振る舞いを明らかにすることができる。そして、この転位を転位除去部(無転位化部)の成長に伴って外方へ抜けるように消滅させるか、あるいは、ループとして消滅させることができる。これにより、無転位化部を、軸状転位を有さない無転位化された状態にできる。そして、無転位化部を無転位化した上で、シリコン単結晶の直径を拡大(拡径)する際の引き上げ条件を容易に求めることが可能となる。 The method for producing a silicon single crystal of the present invention includes the following steps in the method for producing a silicon single crystal in which the silicon single crystal is pulled up by the CZ method. A dipping process in which the seed crystal is brought into contact with the silicon melt to start pulling. A dislocation removing step for forming a dislocation removing portion that removes dislocations generated in the dip step by extending outwardly according to crystal pulling or by annihilating them in a loop shape. A diameter expansion process that raises the shoulder that expands to the required diameter. A straight body process that raises the straight body. A dislocation behavior information acquisition step of detecting dislocation behavior information that is a three-dimensional behavior of dislocations in the dislocation removal unit by irradiating the dislocation removal unit with high energy radiation. A dislocation-free determination step of determining that dislocations are removed based on the dislocation behavior information. A lifting condition setting step of determining a dislocation-free implementation raising condition based on the determination of dislocation-free in the non-dislocation determination step.
This makes it possible to clarify the behavior of dislocations whose behavior has not been clarified. These dislocations can be eliminated so as to escape outward as the dislocation removal portion (dislocation-free portion) grows, or can be eliminated as a loop. Thereby, a dislocation-free part can be made into the dislocation-free state which does not have an axial dislocation. And it becomes possible to obtain | require easily the pulling conditions at the time of enlarging (diameter expanding) the diameter of a silicon single crystal, after making a dislocation-free part dislocation-free.
これによって、従来不可能であった非破壊検査によって引き上げ時に発生した転位の挙動をリアルタイムに観測することが可能となる。そのため、転位除去部(無転位化部)の転位が除去され、無転位化されたことを確認した後に、シリコン単結晶を引き上げて、ショルダー部(拡径部)および直胴部を形成することができる。そのため、ショルダー部及び直胴部に軸状転位のない無転位の結晶を安全かつ容易に引き上げることができる。 The method for producing a silicon single crystal of the present invention includes the following steps in the method for producing a silicon single crystal in which the silicon single crystal is pulled up by the CZ method. A dipping process in which the seed crystal is brought into contact with the silicon melt to start pulling. A dislocation removing step for forming a dislocation removing portion that removes dislocations generated in the dip step by extending outwardly according to crystal pulling or by annihilating them in a loop shape. A diameter expansion process that raises the shoulder that expands to the required diameter. A straight body process that raises the straight body. A dislocation behavior information acquisition step of detecting dislocation behavior information that is a three-dimensional behavior of dislocations in the dislocation removal unit by irradiating the dislocation removal unit with high energy radiation. A dislocation-free determination step of determining that dislocations are removed based on the dislocation behavior information. And based on the determination of non-dislocation in the non-dislocation determination step, the diameter expansion step is started.
As a result, it becomes possible to observe in real time the behavior of dislocations that occurred during the pull-up by nondestructive inspection, which was impossible in the past. Therefore, after confirming that the dislocations in the dislocation removing part (dislocation-free part) are removed and dislocation-free, the silicon single crystal is pulled up to form the shoulder part (expanded part) and the straight body part. Can do. Therefore, dislocation-free crystals having no axial dislocations in the shoulder portion and the straight body portion can be pulled up safely and easily.
これにより、高エネルギー放射光が、無転位結晶育成に必要な転位状態の情報を取得するために充分なエネルギーを有する。
また、前記高エネルギー放射光が、回転数0.1~30rpmで回転状態として転位除去部に照射されてもよい。
これにより、転位の3次元情報を取得することができる。また非破壊で転位の3次元情報を取得することができる。
ここで、高エネルギー放射光が回転状態で照射されるとは、次のことを含む。転位除去部(無転位化部)が結晶が成長する方向の中心軸を回転中心軸として回転し、この転位除去部に高エネルギー放射光を照射すること。高エネルギー放射光の照射源と転位除去部とがこれに匹敵する相対運動状態で、転位情報を取得するための高エネルギー放射光照射がおこなわれること。 In the silicon single crystal manufacturing method, the high energy radiation light may have an energy of 40 keV to 70 keV.
Thereby, high energy synchrotron radiation has sufficient energy to acquire information on dislocation states necessary for growth of dislocation-free crystals.
Further, the dislocation removing unit may be irradiated with the high energy radiation light in a rotational state at a rotational speed of 0.1 to 30 rpm.
Thereby, the three-dimensional information of dislocation can be acquired. In addition, non-destructive three-dimensional information of dislocations can be acquired.
Here, the irradiation with high energy radiation light in a rotating state includes the following. The dislocation removing unit (dislocation-free unit) rotates with the central axis in the direction of crystal growth as the rotation center axis, and the dislocation removing unit is irradiated with high energy radiation. High energy synchrotron radiation for acquiring dislocation information is performed in a relative motion state where the irradiation source of the high energy synchrotron radiation and the dislocation removal unit are comparable.
このように、転位を消滅させることにより、無転位化部を無転位化した上でシリコン単結晶を引き上げて直径を拡大し、直胴部を成長させることが可能となる。あるいは、無転位化部が無転位化したことを確認した後に、シリコン単結晶を成長させてショルダー部(拡径部)および直胴部を成長させることが可能となる。これにより、シリコン単結晶の重量を支持するために必要な直径を維持することができる。したがって、大きな重量の軸状転位がない無転位の結晶をシリコン融液から安全かつ容易に引き上げることができる。 According to the present invention, it is possible to clarify the behavior of difficult-to-remove dislocations whose behavior has not been clarified. Further, this dislocation can be eliminated so as to escape outward along with the growth of the dislocation removing portion. Alternatively, dislocations can be eliminated as loops.
Thus, by eliminating the dislocations, the dislocation-free portion is made dislocation-free, the silicon single crystal is pulled up to increase the diameter, and the straight body portion can be grown. Alternatively, after confirming that the dislocation-free portion has been dislocation-free, it is possible to grow a silicon single crystal to grow a shoulder portion (expanded diameter portion) and a straight body portion. Thereby, the diameter required to support the weight of the silicon single crystal can be maintained. Therefore, dislocation-free crystals having no large weight of axial dislocations can be safely and easily pulled up from the silicon melt.
図1は、本実施形態におけるシリコン単結晶の製造装置を示す模式正面図である。
チョクラルスキー法(以下、CZ法という)を用いたシリコン単結晶の製造装置であるCZ炉は、図1に示すように、ルツボ1と、ヒータ2と、引き上げ軸4と、シードチャック5と、熱遮蔽部(熱遮蔽体)7と、磁場発生部(磁場供給装置)9とを備えている。 Hereinafter, a method for producing a silicon single crystal according to a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic front view showing an apparatus for producing a silicon single crystal in the present embodiment.
As shown in FIG. 1, a CZ furnace which is a silicon single crystal manufacturing apparatus using the Czochralski method (hereinafter referred to as CZ method) includes a
ヒータ2は、ルツボ1の外側に配置されている。ヒータ2としては、例えば抵抗加熱ヒータを用いることができる。ヒータ2は、ルツボ1に収容されたシリコン融液3の温度を融点以上の温度に加熱し、その温度を維持することができれば、抵抗加熱ヒータに限定されない。
引き上げ軸4は、鉛直方向に平行な軸回りに任意の回転速度で回転する。また、引き上げ軸4は、鉛直方向に平行な軸方向に任意の速度で移動する。
シードチャック5は、引き上げ軸4の下端部に設けられ、シリコンの種結晶Tを保持する。
図1に示すCZ炉においてシリコン単結晶6を育成する際には、引き上げ軸4を下降させ、シードチャック5に取り付けた種結晶Tをシリコン融液3に浸漬する。その後、ルツボ1および引き上げ軸4を回転させつつ、引き上げ軸4を上昇させて種結晶T及びシリコン単結晶6を引き上げる。 The
The
The pulling
The
When the silicon
熱遮蔽部7の下部の半径方向の幅(厚み)Wは例えば約50mmである。逆円錐台面である熱遮蔽部7の内側の面の鉛直方向に対する傾きθは、例えば約21°である。シリコン融液3の液面から熱遮蔽部7の下端までの高さH1は例えば約10mmから250mm程度までの範囲内である。高さH1は、例えば50mm又は100mmとしてもよい。また、後述する各工程においてその高さH1をそれぞれ設定してもよい。 The
The width (thickness) W in the radial direction of the lower part of the
シリコン単結晶6を製造する際には、引き上げ条件を変化させることで、発生する転位の状態及び転位の挙動が変化する。そこで、本実施形態のシリコン単結晶の製造方法においては、転位を除去することができるシリコン単結晶6の引き上げ条件を設定する。 Next, a method for producing a silicon single crystal using the CZ furnace shown in FIG. 1 will be described.
When the silicon
なお、工程S00におけるシリコン単結晶6の引き上げ条件は、予め、シリコン単結晶6の引き上げを異なる条件で複数回行って採取したデータを用いてもよい。この場合、製造するシリコン単結晶6の仕様に基づき、引き上げ条件を選択する。 First, in step S00, a pulling condition that can make the silicon
Note that as the pulling conditions for the silicon
本実施形態においては、ルツボ1に300kgのシリコン多結晶を投入する。ドーパントの濃度は、例えば、製造するシリコン単結晶6の直胴部6bの抵抗値が12Ωcmとなるように調整する。
ここで、CZ炉の内部の雰囲気を不活性ガスとし、不活性ガスの圧力を1.3kPaから13.3kPaまで(10torrから100torrまで)の範囲内に調整する。本実施形態においては、CZ炉の内部の雰囲気は、例えば、圧力50Torr(6.666kPa)のArガスとする。なお、CZ炉の内部の雰囲気は、水素ガスを含有してもよい。
また、磁場発生部9により例えば3000G(0.3T)の水平磁場を発生させ、ヒータ2によりシリコン多結晶を加熱して溶融させる。このとき、磁場の中心の高さを、シリコン融液3の液面下75mmから液面上50mmまでの範囲内とする。磁場を用いるCZ法(MCZ法)を適用する場合には、シリコン融液3に印加する横磁場を2000Gから4000Gまでの範囲内としてもよい。 Next, in step S01, high-purity silicon polycrystal is put into the
In the present embodiment, 300 kg of silicon polycrystal is put into the
Here, the atmosphere inside the CZ furnace is an inert gas, and the pressure of the inert gas is adjusted within a range from 1.3 kPa to 13.3 kPa (from 10 torr to 100 torr). In the present embodiment, the atmosphere inside the CZ furnace is, for example, Ar gas having a pressure of 50 Torr (6.666 kPa). The atmosphere inside the CZ furnace may contain hydrogen gas.
Further, a horizontal magnetic field of, for example, 3000 G (0.3 T) is generated by the
図5の(b)は、縦軸を光子数、横軸を波長として、照射部RのX線の光源から距離44mの位置で、1mm×1mmのスリットを通して得られる光子数の分布を示すグラフである。
ここで、X線のビーム径は、被測定物である無転位化部Nの直径の0.01倍から1倍までの範囲内とすることが好ましい。 FIG. 5A is a graph showing the distribution of the number of photons obtained through a 1 mm × 1 mm slit at a distance of 44 m from the X-ray light source of the irradiation unit R, with the vertical axis representing the number of photons and the horizontal axis representing energy. It is.
FIG. 5B is a graph showing the distribution of the number of photons obtained through a 1 mm × 1 mm slit at a distance of 44 m from the X-ray light source of the irradiation unit R, where the vertical axis represents the number of photons and the horizontal axis represents the wavelength. It is.
Here, the X-ray beam diameter is preferably in the range of 0.01 to 1 times the diameter of the dislocation-free portion N that is the object to be measured.
また、図6に示す白色X線トポグラフィにより、バーガースベクトルなどの転位の性質を測定する。図6において、検出位置d1からd7は、白色X線の回折方向に対応している。各検出位置は、例えば、結晶方位[-1 1 1]、[-1 1 3]、[0 0 4]、[1 -1 3]、[1 -1 1]におけるラウエトポグラフを取得する位置に対応している。ここで、上記の結晶方位における-1は、上線が付された1を意味する。 In step S12, as shown in FIG. 4, the irradiation angle ω of the high-energy radiation light B is set with respect to the axis N4 of the dislocation-free portion N of the silicon
Further, dislocation properties such as Burgers vector are measured by white X-ray topography shown in FIG. In FIG. 6, the detection positions d1 to d7 correspond to the diffraction direction of white X-rays. Each detection position is, for example, a position where a Laue topograph is acquired at crystal orientations [-1 1 1], [-1 1 3], [0 0 4], [1 -1 3], [1 -1 1]. It corresponds. Here, −1 in the above crystal orientation means 1 with an overline.
すなわち、最初に工程S00において設定した引き上げ条件によって、無転位化部Nの転位が除去された場合には、その引き上げ条件をデータベースに記録し、工程S00においてその引き上げ条件を用いる。最初に工程S00において設定した引き上げ条件によって、無転位化部Nの転位が除去されなかった場合には、その引き上げ条件を工程S00において用いないようにデータベースに記録し、S00において無転位化部Nの無転位化が可能と思われる新たな引き上げ条件を設定する。 Next, the determination of dislocation-free in step S13 is fed back to step S00.
That is, when dislocations in the dislocation-free portion N are removed by the pulling conditions initially set in step S00, the pulling conditions are recorded in the database, and the pulling conditions are used in step S00. When dislocations in the dislocation-free portion N are not removed by the pulling conditions initially set in the step S00, the pulling conditions are recorded in the database so that they are not used in the step S00. A new pulling condition that can be dislocation free is set.
また、工程S12及び工程S13により、転位の発生及び除去の状況を正確に把握することができる。
また、工程S00から工程S06及び工程S11から工程S13を繰り返すことで、無転位化が可能なシリコン単結晶の引き上げ条件を正確に決定することができる。
また、シリコン単結晶6のネック部すなわち無転位化部Nの直径を必要以上に小さくしなくても、無転位化部Nにおける転位を除去することができる。したがって、特別な処理や装置を必要とすることなく、簡便な方法で、転位が除去された直径450mm程度の重量の大きなシリコン単結晶6を安全に育成することができる。 As described above, according to the method for manufacturing a silicon single crystal of the present embodiment, dislocations N are formed, so that dislocations generated in the step of bringing the seed crystal T into contact with the
In addition, the state of dislocation generation and removal can be accurately grasped by the steps S12 and S13.
Further, by repeating the steps S00 to S06 and the steps S11 to S13, it is possible to accurately determine the pulling conditions for the silicon single crystal that can be dislocation-free.
Further, dislocations in the dislocation-free portion N can be removed without making the neck portion of the silicon
本実施形態において、前述した第1実施形態に対応する部分には同一の符号を付して説明を省略する。 Hereinafter, a method for producing a silicon single crystal according to a second embodiment of the present invention will be described with reference to the drawings.
In the present embodiment, parts corresponding to those of the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.
照射部Rは、チャンバー内に位置する引き上げ中の無転位化部Nに対して高エネルギー放射光Bを照射する。検出部dは、無転位化部Nに照射された高エネルギー放射光Bの回折光を検出する。照射部R及び検出部dは、軸N4とほぼ一致する引き上げ軸4に対する高エネルギー放射光Bの角度ωを調整できるように設けられている。 As shown in FIG. 9, the CZ furnace of the present embodiment includes a
The irradiation part R irradiates the high-energy radiation light B to the dislocation-free part N being pulled up and located in the chamber. The detection part d detects the diffracted light of the high energy radiation light B irradiated to the dislocation-free part N. The irradiation part R and the detection part d are provided so that the angle ω of the high-energy radiated light B with respect to the pulling
本実施形態では、シリコン単結晶の全長に亘ってシリコン単結晶の引き上げ方向に延びる軸状転位(除去困難転位)を除去することができるシリコン単結晶の製造方法について説明する。 Next, a third embodiment of the present invention will be described with reference to the drawings.
In the present embodiment, a method for producing a silicon single crystal capable of removing axial dislocations (hardly removed dislocations) extending in the pulling direction of the silicon single crystal over the entire length of the silicon single crystal will be described.
まず、シリコン単結晶のウェーハの表面において、光学的な検査手段により内部応力の分布状態を観察することができる例えばJENA WAVE社製の歪み検査装置(SIRD:登録商標)SirTecを使用し、歪みを測定する。 Axial dislocations can be detected separately from pits by the following method.
First, on the surface of a silicon single crystal wafer, a strain inspection apparatus (SIRD: registered trademark) SirTec manufactured by JENA WAVE can be used to observe the internal stress distribution state by an optical inspection means. taking measurement.
種結晶T0の近傍を拡大すると、図13に示すように、種結晶T0をシリコン融液に接触させた際の熱ショックにより、種結晶T0において発生してネック部N0まで連続する熱ショック転位Jnが発生する。種結晶T0とネック部N0に格子定数の不整合がある場合には、ネック部N0にミスフィット転位Jmが発生する。 As shown in FIG. 12, a silicon
When the vicinity of the seed crystal T0 is enlarged, as shown in FIG. 13, the heat shock dislocation Jn generated in the seed crystal T0 and continuing to the neck portion N0 due to the heat shock when the seed crystal T0 is brought into contact with the silicon melt. Will occur. When there is a mismatch in lattice constant between the seed crystal T0 and the neck portion N0, a misfit dislocation Jm occurs in the neck portion N0.
第1に、熱ショック転位Jnおよびミスフィット転位Jmは、通常、シリコンのすべり面である{111}面を移動する。
第2に、熱ショック転位Jnおよびミスフィット転位Jmは、通常、{111}面に導入される。
第3に、熱ショック転位Jnおよびミスフィット転位Jmは、まれに{111}面に導入されずに他の面を移動する場合があるが、すぐに{111}面に移動する。
第4に、熱ショック転位Jnおよびミスフィット転位Jmのほとんどは、種結晶をシリコン融液に接触させた時に発生する。 In the process of growing a silicon single crystal when pulling up the neck portion, shoulder portion and straight body portion, the direction in which the heat shock dislocation Jn and the misfit dislocation Jm propagate has the following characteristics.
First, the heat shock dislocation Jn and the misfit dislocation Jm usually move on the {111} plane, which is a silicon slip plane.
Secondly, the heat shock dislocation Jn and the misfit dislocation Jm are usually introduced into the {111} plane.
Thirdly, the heat shock dislocation Jn and the misfit dislocation Jm rarely are introduced into the {111} plane and may move to other planes, but immediately move to the {111} plane.
Fourth, most of the heat shock dislocations Jn and misfit dislocations Jm occur when the seed crystal is brought into contact with the silicon melt.
一方で、シリコン単結晶の成長方向に伸びた熱ショック転位Jnおよびミスフィット転位Jmは、ショルダー部の形成中又は直胴部の形成中に{111}面へ移動する場合がある。 In this case, the heat shock dislocation Jn and the misfit dislocation Jm do not reach the surface of the silicon single crystal even when the diameter of the silicon single crystal increases to the product diameter, and are axial dislocations existing inside the straight body portion. May be. Thus, a silicon single crystal having axial dislocations in the straight body portion has a habit line similar to a silicon single crystal having no axial dislocations in the straight body portion, and is a non-defective product in an ingot state. It may not be possible to distinguish. The axial dislocation is confirmed as a defect when a wafer is manufactured from the ingot.
On the other hand, the heat shock dislocation Jn and the misfit dislocation Jm extending in the growth direction of the silicon single crystal may move to the {111} plane during the formation of the shoulder portion or the straight body portion.
したがって、本実施形態では、{111}面に存在しない熱ショック転位Jnおよびミスフィット転位Jmを、ネック部を形成する工程で{111}面に移動させるための方法を説明する。具体的には、ネック部の形成時のシリコン単結晶とシリコン融液との界面の形状を制御する。そして、その条件を確認するためにX線トポグラフィを用いる。 As described above, the heat shock dislocation Jn and the misfit dislocation Jm at the time of forming the neck portion progress not perpendicular to the {111} plane but perpendicular to the interface between the silicon single crystal and the silicon melt.
Therefore, in the present embodiment, a method for moving the heat shock dislocation Jn and the misfit dislocation Jm that do not exist in the {111} plane to the {111} plane in the step of forming the neck portion will be described. Specifically, the shape of the interface between the silicon single crystal and the silicon melt when the neck portion is formed is controlled. And X-ray topography is used in order to confirm the conditions.
本実施形態のシリコン単結晶の製造方法は、図2に示す第1実施形態におけるシリコン単結晶の製造方法と同様に、工程S01から工程S06及び工程S11から工程S13を有している。又は、図10に示す第2実施形態におけるシリコン単結晶の製造方法と同様に、工程S01から工程S06、工程S22及び工程S23を有している。本実施形態では、工程S03において上記の軸状転位を除去する点で、上記の第1実施形態及び第2実施形態と異なっている。 Hereinafter, the manufacturing method of the silicon single crystal of this embodiment will be described in detail with reference to the drawings.
The method for manufacturing a silicon single crystal according to this embodiment includes steps S01 to S06 and steps S11 to S13, as in the method for manufacturing a silicon single crystal according to the first embodiment shown in FIG. Or similarly to the manufacturing method of the silicon single crystal in 2nd Embodiment shown in FIG. 10, it has process S01 to process S06, process S22, and process S23. The present embodiment is different from the first and second embodiments in that the axial dislocation is removed in step S03.
なお、レーザ照射部La及びガス供給部Gは、引き上げ軸4を中心として回転するように設けられていなくてもよい。この場合、レーザ照射部La及びガス供給部Gを固定して、レーザ照射部La及びガス供給部Gから、所定のタイミングでレーザ光及び冷却ガスを断続的に照射及び供給してもよい。 As shown in FIG. 14, the CZ furnace of this embodiment includes a laser irradiation unit La and a gas supply unit G as a temperature adjustment mechanism of the dislocation-free portion N of the silicon single crystal. The laser irradiation unit La and the gas supply unit G are provided so as to rotate around the pulling
The laser irradiation unit La and the gas supply unit G may not be provided so as to rotate around the pulling
その後、工程S03において、引き上げ軸4を上昇させ、種結晶Tの下方にシリコン単結晶を成長させて無転位化部Nを形成する。
工程S02においては、種結晶Tを回転させながら降下させ、種結晶Tの下端部をシリコン融液3に浸漬する。種結晶Tの下端部をシリコン融液3に浸漬した後、種結晶Tの下降を停止して、種結晶Tとシリコン融液3とを十分になじませる。そして、種結晶Tの下端部の一部をシリコン融液3に溶け込ませる。 In the present embodiment, in step S02, first, as shown in FIGS. 3A and 3B, the seed crystal T is brought into contact with the
Thereafter, in step S03, the pulling
In step S02, the seed crystal T is lowered while being rotated, and the lower end portion of the seed crystal T is immersed in the
しかし、原料となるシリコン多結晶を融解した直後は、シリコン融液3の温度は局所的な温度の変動が大きく、不安定な状態になる。このため、工程S02は、原料となるシリコン多結晶を融解した後、所定の時間が経過してから実施される。 If the
However, immediately after the silicon polycrystal as a raw material is melted, the temperature of the
シリコン融液3の液面における温度が低すぎる場合には、種結晶Tの下端部の側面に結晶が成長して、張り出した状態になる。このような状態で工程S02から工程S03に移行すると、無転位化部Nに新たな転位が発生する。 When the temperature at the liquid surface of the
When the temperature at the liquid surface of the
すなわち、シリコン単結晶の引き上げ速度を制御することで、シリコン単結晶とシリコン融液3との界面K1,K2の形状を制御することができる。 When the pulling speed of the silicon single crystal is lower than a predetermined speed, the interface K1 between the silicon single crystal and the
That is, by controlling the pulling rate of the silicon single crystal, the shapes of the interfaces K1, K2 between the silicon single crystal and the
そのため、図16の(b)に示すように、界面K1が下方に凸の曲面の場合、転位jのほとんどはシリコン単結晶の無転位化部Nの径方向の外側へ向けて進展する。また、図16の(c)に示すように、界面K2が上方に凸の曲面の場合、転位jのほとんどはシリコン単結晶の無転位化部Nの径方向の内側へ向けて進展する。 The silicon single crystal grows in a direction perpendicular to the interfaces K1 and K2. Further, the dislocation j progresses in the direction in which the silicon single crystal grows. That is, the dislocation j progresses in the normal direction of a virtual tangent plane between the interfaces K1 and K2 between the silicon single crystal and the
Therefore, as shown in FIG. 16B, when the interface K1 is a downwardly convex curved surface, most of the dislocations j progress outward in the radial direction of the dislocation-free portion N of the silicon single crystal. As shown in FIG. 16C, when the interface K2 is an upwardly convex curved surface, most of the dislocations j progress toward the radially inner side of the dislocation-free portion N of the silicon single crystal.
したがって、仮想的な接平面が水平ではない界面K1,K2上の任意の点から延びる転位jを除去し、軸状転位Jの発生を防止できる。 That is, when the interface K1 is a downwardly convex curved surface, the dislocation j advances toward the outer side in the radial direction of the dislocation-free portion N of the silicon single crystal and reaches the outer peripheral surface of the silicon single crystal, thereby dislocation-free. Part N is removed. In addition, when the interface K2 is an upwardly convex curved surface, the dislocation j progresses inward in the radial direction of the dislocation-free portion N of the silicon single crystal and is eliminated at the dislocation-free portion N by annihilating the pair. The
Therefore, the dislocation j extending from an arbitrary point on the interfaces K1, K2 whose virtual tangent plane is not horizontal can be removed, and the occurrence of the axial dislocation J can be prevented.
引き上げ速度の変化によって、転位の進展する方向がシリコン単結晶の引き上げ方向からずれることがある。この現象は転位除去のためには好ましい。 When dislocation j is advanced toward the central axis of the silicon single crystal to be annihilated, or is advanced toward the outer peripheral surface of the silicon single crystal and removed, the dislocation j is formed when the pulling speed of the silicon single crystal fluctuates. The diameter of the silicon single crystal may vary. At this time, even if the diameter of the silicon single crystal is reduced to some extent, there is no problem as long as the diameter of the silicon single crystal finally formed can be held. Even if the diameter of the silicon single crystal is increased to some extent, there is no problem as long as the raw material is not wasted. Therefore, the diameter of the silicon single crystal may vary to some extent as long as the pulling of the straight body portion of the silicon single crystal is not adversely affected.
Due to the change in pulling speed, the direction in which dislocations progress may deviate from the pulling direction of the silicon single crystal. This phenomenon is preferable for dislocation removal.
ここで、図14又は図15に示すようなCZ炉を用いて、シリコン単結晶の無転位化部Nを一方向から加熱又は冷却することで、界面K1,K2にシリコン単結晶の中心軸方向に垂直な温度分布を生じさせる。 When a temperature distribution in the radial direction, that is, a temperature gradient in the radial direction does not occur in the silicon single crystal, as shown in FIGS. 16B and 16C, the dislocation-free portion N and the
Here, by using a CZ furnace as shown in FIG. 14 or FIG. 15, the dislocation-free portion N of the silicon single crystal is heated or cooled from one direction, so that the interface K1, K2 has the center axis direction of the silicon single crystal. A temperature distribution perpendicular to is generated.
また、ガス供給部Gによってレーザ照射部Laと反対側から冷却ガスを供給する。これにより、無転位化部Nが加熱される方向と逆の方向から、無転位化部Nの界面K1,K2の近傍を冷却する。 When the CZ furnace shown in FIG. 14 is used, the vicinity of the interfaces K1, K2 of the dislocation-free portion N is heated from one direction by irradiating laser light from the laser irradiation portion La.
Further, the cooling gas is supplied from the side opposite to the laser irradiation unit La by the gas supply unit G. Thereby, the vicinity of the interfaces K1, K2 of the dislocation-free portion N is cooled from the direction opposite to the direction in which the dislocation-free portion N is heated.
このようにして、界面K1,K2に、引き上げ軸4の上昇方向に垂直な温度勾配を生じさせる。 When the CZ furnace shown in FIG. 15 is used, the radiant heat of the
In this way, a temperature gradient perpendicular to the rising direction of the lifting
種結晶の直径を300mmとして、無転位化部を成長させる。
ここで、図2に示す工程S00における引き上げ条件として、表2に示すサンプル1からサンプル5までの5つの異なる条件を用いて、工程S00から工程S06及び工程S11から工程S13を実行した。具体的には、表2に示すように、引き上げ軸の引き上げ速度と、熱遮蔽部とシリコン融液の液面からの距離(高さ)と、種結晶をシリコン融液に浸漬して保持する保持時間との異なる5つの組合せを用いた。 In this embodiment, 300 kg of silicon polycrystal is put into a crucible. The concentration of the dopant is adjusted so that the resistance value of the straight body portion of the silicon single crystal to be manufactured is 12 Ωcm. The atmosphere inside the CZ furnace is Ar gas having a pressure of 50 Torr (6.666 kPa).
The dislocation-free part is grown with the diameter of the seed crystal being 300 mm.
Here, using the five different conditions from
したがって、工程S00における引き上げ条件として、引き上げ軸の引き上げ速度は0.5mm/minから1.5mm/minまでの範囲内、シリコン融液との距離(高さ)は、100mmから150mmの範囲内、保持時間は100minに設定する。これにより、無転位化部の転位を除去し、シリコン単結晶のショルダー部及び直胴部の転位を除去することができた。 In step S13 shown in FIG. 2, the state of each sample was observed. In
Therefore, as the pulling conditions in step S00, the pulling speed of the pulling shaft is in the range from 0.5 mm / min to 1.5 mm / min, and the distance (height) from the silicon melt is in the range of 100 mm to 150 mm. The holding time is set to 100 min. As a result, dislocations at the dislocation-free portion were removed, and dislocations at the shoulder portion and the straight body portion of the silicon single crystal could be removed.
次に、実施例1と同様に、軸状転位の除去を行った。
その結果、図2に示す工程S13において、図18の(b)に示すように、無転位化部において軸状転位が除去されていると判断される状態になる。または、図18の(c)に示すように、転位の進展する方向が、シリコン単結晶の中心軸の方向と異なる{1 1 1}面に移動し、無転位化部において転位がシリコン単結晶の外周面に達して除去されている状態になる。 When a silicon single crystal is manufactured using a conventional method, an axial dislocation extending in the central axis direction of the silicon single crystal exists at the neck portion of the silicon single crystal, as shown in FIG. Yes.
Next, in the same manner as in Example 1, axial dislocations were removed.
As a result, in step S13 shown in FIG. 2, as shown in FIG. 18B, it is determined that the axial dislocation has been removed in the dislocation-free portion. Alternatively, as shown in FIG. 18 (c), the dislocation progress direction moves to a {1 1 1} plane different from the direction of the central axis of the silicon single crystal, and the dislocation is dislocation-free at the silicon single crystal. It reaches a state where it has been removed by reaching the outer peripheral surface of.
本発明のシリコン単結晶の製造方法は、以下の課題の少なくとも一つを解決する。種結晶をシリコン融液に接触させる工程で発生する転位を除去して、無転位化を実現すること。転位の発生及び除去の状況を正確に把握すること。ネック部での転位の状態とシリコン単結晶の引き上げの条件との関係を正確に把握すること。無転位化が可能なシリコン単結晶の引き上げ条件を正確に決定すること。 The method for producing a silicon single crystal of the present invention includes the following steps. A step of growing a silicon single crystal by bringing the seed crystal into contact with the silicon melt and then pulling it up. A step of forming dislocation-free portions in the silicon single crystal by causing dislocations generated in the silicon single crystal to be removed by extending outward in the radial direction of the silicon single crystal or eliminating them in a loop; A step of pulling up the silicon single crystal on which the dislocation-free portion is formed and expanding it to a predetermined diameter to form a straight body portion;
The method for producing a silicon single crystal of the present invention solves at least one of the following problems. Dislocations generated in the process of bringing the seed crystal into contact with the silicon melt are removed to realize dislocation-free. To accurately grasp the occurrence and removal of dislocations. To accurately grasp the relationship between the state of dislocations at the neck and the conditions for pulling up the silicon single crystal. To accurately determine the pulling conditions for silicon single crystals that can be dislocation-free.
Claims (22)
- シリコン単結晶をCZ法により引き上げるシリコン単結晶の製造方法において、
シリコン融液に種結晶を接触させ、前記シリコン単結晶の引き上げを開始するディップ工程と、
シリコンウェーハとなる前記シリコン単結晶の直胴部を形成するように、前記シリコン単結晶を引き上げる直胴工程と、
ディップ工程で発生した転位又は除去困難転位を前記直胴工程より前に除去する除去困難転位除去工程と、
を有するシリコン単結晶の製造方法。 In the method for producing a silicon single crystal in which the silicon single crystal is pulled by the CZ method,
A dipping step of bringing a seed crystal into contact with the silicon melt and starting to pull up the silicon single crystal;
A straight body step of pulling up the silicon single crystal so as to form a straight body portion of the silicon single crystal to be a silicon wafer;
A dislocation removal or dislocation removal step that removes dislocations or difficult dislocations generated in the dip step before the straight body step; and
The manufacturing method of the silicon single crystal which has this. - シリコン融液に種結晶を接触させるディップ工程と、
前記シリコン融液から前記種結晶を引き上げてシリコン単結晶を育成し、前記ディップ工程において発生した転位を、前記シリコン単結晶の径方向の外側へ進展させて除去するか又はループ状に対消滅させて除去することで、無転位化部を形成する除去困難転位除去工程と、
前記無転位化部が形成された前記シリコン単結晶を引き上げて所定の直径まで拡大させ、直胴部を形成する直胴工程と、を有し、
前記種結晶から前記シリコン単結晶の中心軸方向又は結晶成長方向に延びて前記直胴部に達する軸状転位の発生を防止するシリコン単結晶の製造方法。 A dipping process in which the seed crystal is brought into contact with the silicon melt;
The seed crystal is pulled up from the silicon melt to grow a silicon single crystal, and the dislocations generated in the dipping process are removed by extending outward in the radial direction of the silicon single crystal or annihilated in a loop shape. Removing the difficult dislocation removal step to form a dislocation-free portion,
A straight cylinder step of pulling up the silicon single crystal in which the dislocation-free part is formed and expanding the silicon single crystal to a predetermined diameter to form a straight cylinder part, and
A method for producing a silicon single crystal, which prevents the occurrence of axial dislocations extending from the seed crystal in a center axis direction or a crystal growth direction of the silicon single crystal and reaching the straight body part. - 前記除去困難転位除去工程において、前記転位又は前記除去困難転位が伸展する方向を結晶成長方向から移動させる請求項1記載のシリコン単結晶の製造方法。 The method for producing a silicon single crystal according to claim 1, wherein, in the difficult-to-remove dislocation removal step, a direction in which the dislocation or the difficult-to-remove dislocation extends is moved from a crystal growth direction.
- 前記除去困難転位除去工程において、前記転位又は前記除去困難転位を前記シリコン結晶の引き上げに従って、前記シリコン単結晶の外部方向へ伸展させるか又はループ状に対消滅させて除去する請求項1記載のシリコン単結晶の製造方法。 2. The silicon according to claim 1, wherein in the difficult-to-removal dislocation removing step, the dislocation or the difficult-to-remove dislocation is removed by extending toward the outside of the silicon single crystal or annihilating in a loop shape according to pulling up of the silicon crystal. A method for producing a single crystal.
- 前記除去困難転位除去工程において、前記シリコン融液と前記シリコン単結晶との固液界面形状を前記シリコン融液の表面から変形させて前記転位又は前記除去困難転位が伸展する方向を前記結晶成長方向から移動させる請求項3記載のシリコン単結晶の製造方法。 In the difficult removal dislocation removal step, the crystal growth direction is the direction in which the dislocation or the difficult removal dislocation extends by deforming the shape of the solid-liquid interface between the silicon melt and the silicon single crystal from the surface of the silicon melt. A method for producing a silicon single crystal according to claim 3, wherein
- 前記除去困難転位除去工程において、前記シリコン融液と前記シリコン単結晶との固液界面の接平面が前記シリコン融液の表面と平行となる部分を中心位置から変動させて前記転位又は前記除去困難転位が伸展する方向を前記結晶成長方向から移動させる請求項5記載のシリコン単結晶の製造方法。 In the difficult-to-removal dislocation removing step, the dislocation or the difficult-to-remove by changing a portion where a tangential plane of a solid-liquid interface between the silicon melt and the silicon single crystal is parallel to the surface of the silicon melt from a central position. 6. The method for producing a silicon single crystal according to claim 5, wherein a direction in which dislocations extend is moved from the crystal growth direction.
- 前記除去困難転位除去工程において、前記シリコン融液と前記シリコン単結晶との固液界面状態の揺らぎを増大して前記転位又は前記除去困難転位が伸展する方向を前記結晶成長方向から移動させる請求項3記載のシリコン単結晶の製造方法。 The step of removing the dislocations or the dislocations that are difficult to remove, and increasing the fluctuation of the solid-liquid interface state between the silicon melt and the silicon single crystal to move the dislocation or the direction in which the dislocations that are difficult to remove extend from the crystal growth direction. 3. A method for producing a silicon single crystal according to 3.
- 前記除去困難転位除去工程において、前記シリコン融液に対する前記シリコン単結晶の回転を低減して前記固液界面状態の揺らぎを増大する請求項7記載のシリコン単結晶の製造方法。 The method for producing a silicon single crystal according to claim 7, wherein, in the difficult-to-remove dislocation removal step, rotation of the silicon single crystal with respect to the silicon melt is reduced to increase fluctuation of the solid-liquid interface state.
- 前記除去困難転位除去工程において、前記シリコン融液に印加する磁場強度を低減して前記固液界面状態の揺らぎを増大する請求項7記載のシリコン単結晶の製造方法。 The method for producing a silicon single crystal according to claim 7, wherein, in the difficult-to-remove dislocation removing step, the magnetic field strength applied to the silicon melt is reduced to increase the fluctuation of the solid-liquid interface state.
- 前記除去困難転位除去工程において、前記シリコン融液を貯留する石英ルツボに起因して発生する湯面振動により前記固液界面状態の揺らぎを増大する請求項7記載のシリコン単結晶の製造方法。 The method for producing a silicon single crystal according to claim 7, wherein, in the difficult-to-remove dislocation removal step, fluctuations in the solid-liquid interface state are increased by vibration of a molten metal surface caused by a quartz crucible storing the silicon melt.
- 前記除去困難転位除去工程において、前記シリコン単結晶を成長軸又は前記シリコン単結晶の中心軸に対して非対称に加熱して前記固液界面状態の揺らぎを増大する請求項7記載のシリコン単結晶の製造方法。 8. The silicon single crystal according to claim 7, wherein in the difficult-to-remove dislocation removing step, the fluctuation of the solid-liquid interface state is increased by heating the silicon single crystal asymmetrically with respect to a growth axis or a central axis of the silicon single crystal. Production method.
- 前記除去困難転位除去工程において、前記シリコン融液と前記シリコン単結晶との固液界面を成長軸又は前記シリコン単結晶の中心軸に対して非対称になるように温度分布を形成して前記転位又は前記除去困難転位が伸展する方向を前記結晶成長方向から移動させる請求項7記載のシリコン単結晶の製造方法。 In the difficult-to-remove dislocation removal step, the dislocation or the dislocation or the temperature distribution is formed so that the solid-liquid interface between the silicon melt and the silicon single crystal is asymmetric with respect to the growth axis or the center axis of the silicon single crystal. The method for producing a silicon single crystal according to claim 7, wherein a direction in which the difficult-to-remove dislocation extends is moved from the crystal growth direction.
- 前記除去困難転位除去工程において、前記シリコン単結晶を成長軸又は前記シリコン単結晶の中心軸に対して非対称に加熱して前記固液界面を成長軸又は前記シリコン単結晶の中心軸に対して非対称にする請求項12記載のシリコン単結晶の製造方法。 In the difficult-to-remove dislocation removal step, the silicon single crystal is heated asymmetrically with respect to the growth axis or the central axis of the silicon single crystal, so that the solid-liquid interface is asymmetric with respect to the growth axis or the central axis of the silicon single crystal. The method for producing a silicon single crystal according to claim 12.
- 前記除去困難転位除去工程において、前記ディップ工程で発生した転位を前記シリコン単結晶の引き上げに従って前記シリコン単結晶の外部方向へ伸展させるか又はループ状に対消滅させて除去し、前記シリコン単結晶に転位除去部又は無転位化部を形成するとともに、
前記除去困難転位除去工程後に前記シリコン単結晶の直径を前記直胴部の直径まで拡大してショルダー部を形成するように、前記シリコン単結晶を引き上げる拡径工程と、
前記転位除去部又は無転位化部に高エネルギー放射光を照射して該転位除去部又は無転位化部内における前記転位の3次元的挙動である転位挙動情報を検出する転位挙動情報取得工程と、
前記転位挙動情報に基づいて、前記転位が除去されていることを判断する無転位化判断工程と、
前記無転位化判断工程における無転位化の判断に基づいて、前記シリコン単結晶を無転位化するための引き上げ条件を決定する引き上げ条件設定工程と、
を有するシリコン単結晶の製造方法。 In the difficult-to-remove dislocation removal step, the dislocation generated in the dip step is removed by extending the silicon single crystal toward the outside according to the pulling up of the silicon single crystal or by annihilating it in a loop shape to form the silicon single crystal. While forming a dislocation removal part or a dislocation-free part,
A diameter expanding step of pulling up the silicon single crystal so as to form a shoulder portion by expanding the diameter of the silicon single crystal to the diameter of the straight body portion after the difficult removal dislocation removing step;
Dislocation behavior information acquisition step of detecting dislocation behavior information that is a three-dimensional behavior of the dislocation in the dislocation removal unit or the non-dislocation unit by irradiating the dislocation removal unit or the non-dislocation unit with high energy radiation;
Based on the dislocation behavior information, a dislocation-free determination step for determining that the dislocation has been removed,
Based on the determination of dislocation-free in the dislocation-free determination step, a pulling condition setting step for determining pulling conditions for dislocation-free the silicon single crystal;
The manufacturing method of the silicon single crystal which has this. - 前記無転位化判断工程における無転位化の判断に基づいて、前記拡径工程を開始する請求項14記載のシリコン単結晶の製造方法。 The method for producing a silicon single crystal according to claim 14, wherein the diameter expansion step is started based on the determination of dislocation-free in the dislocation-free determination step.
- 請求項1から15のいずれか一項に記載のシリコン単結晶製造方法の製造方法により製造されるシリコン単結晶。 A silicon single crystal produced by the production method of the silicon single crystal production method according to any one of claims 1 to 15.
- 請求項16記載のシリコン単結晶から製造されるシリコンウェーハ。 A silicon wafer produced from the silicon single crystal according to claim 16.
- シリコン単結晶をCZ法により引き上げるシリコン単結晶の製造方法において、
シリコン融液に種結晶を接触させ、前記シリコン単結晶の引き上げを開始するディップ工程と、
ディップ工程で発生した転位を、前記シリコン単結晶の引き上げに従って前記シリコン単結晶の外部方向へ伸展させるか又はループ状に対消滅させて除去し、前記シリコン単結晶に転位除去部又は無転位化部を形成する転位除去工程と、
前記シリコン単結晶の直径を必要な直径まで拡大させてショルダー部を形成するように前記シリコン単結晶を引き上げる拡径工程と、
前記シリコン単結晶に前記必要な直径を有する直胴部を形成するように前記シリコン単結晶を引き上げる直胴工程と、
前記転位除去部又は前記無転位化部に高エネルギー放射光を照射して該転位除去部又は前記無転位化部内における前記転位の3次元的挙動である転位挙動情報を検出する転位挙動情報取得工程と、
前記転位挙動情報に基づいて、前記転位が除去されていることを判断する無転位化判断工程と、
前記無転位化判断工程における無転位化の判断に基づいて、前記シリコン単結晶を無転位化するための引き上げ条件を決定する引き上げ条件設定工程と、
を有するシリコン単結晶の製造方法。 In the method for producing a silicon single crystal in which the silicon single crystal is pulled by the CZ method,
A dipping step of bringing a seed crystal into contact with the silicon melt and starting to pull up the silicon single crystal;
Dislocations generated in the dipping process are removed by extending the silicon single crystal in the outward direction according to the pulling up of the silicon single crystal or by annihilating it in a loop form, and dislocation removal or non-dislocation parts in the silicon single crystal Dislocation removal step to form
A diameter expanding step of pulling up the silicon single crystal so as to form a shoulder portion by expanding the diameter of the silicon single crystal to a required diameter;
A straight cylinder step of pulling up the silicon single crystal so as to form a straight cylinder portion having the required diameter in the silicon single crystal;
Dislocation behavior information acquisition step of detecting dislocation behavior information which is a three-dimensional behavior of the dislocation in the dislocation removal unit or the non-dislocation unit by irradiating the dislocation removal unit or the non-dislocation unit with high energy radiation. When,
Based on the dislocation behavior information, a dislocation-free determination step for determining that the dislocation has been removed,
Based on the determination of dislocation-free in the dislocation-free determination step, a pulling condition setting step for determining pulling conditions for dislocation-free the silicon single crystal;
The manufacturing method of the silicon single crystal which has this. - シリコン単結晶をCZ法により引き上げるシリコン単結晶の製造方法において、
シリコン融液に種結晶を接触させ、前記シリコン単結晶の引き上げを開始するディップ工程と、
ディップ工程で発生した転位を前記シリコン単結晶の引き上げに従って前記シリコン単結晶の外部方向へ伸展させるか又はループ状に対消滅させて除去し、前記シリコン単結晶に転位除去部又は無転位化部を形成する転位除去工程と、
前記シリコン単結晶の直径を必要な直径まで拡大させてショルダー部を形成するように、前記シリコン単結晶を引き上げる拡径工程と、
前記シリコン単結晶に前記必要な直径を有する直胴部を形成するように前記シリコン単結晶を引き上げる直胴工程と、
前記転位除去部又は無転位化部に高エネルギー放射光を照射して該転位除去部又は無転位化部内における前記転位の3次元的挙動である転位挙動情報を検出する転位挙動情報取得工程と、
前記転位挙動情報に基づいて、前記転位が除去されていることを判断する無転位化判断工程と、を有し、
前記無転位化判断工程における無転位化の判断に基づいて、前記拡径工程を開始するシリコン単結晶の製造方法。 In the method for producing a silicon single crystal in which the silicon single crystal is pulled by the CZ method,
A dipping step of bringing a seed crystal into contact with the silicon melt and starting to pull up the silicon single crystal;
The dislocations generated in the dip process are removed by extending the silicon single crystal toward the outside according to the pulling of the silicon single crystal or by annihilating it in a loop shape, and dislocation removal or non-dislocation parts are formed in the silicon single crystal. Dislocation removal step to be formed;
A diameter expansion step of pulling up the silicon single crystal so as to form a shoulder portion by expanding the diameter of the silicon single crystal to a required diameter;
A straight cylinder step of pulling up the silicon single crystal so as to form a straight cylinder portion having the required diameter in the silicon single crystal;
Dislocation behavior information acquisition step of detecting dislocation behavior information that is a three-dimensional behavior of the dislocation in the dislocation removal unit or the non-dislocation unit by irradiating the dislocation removal unit or the non-dislocation unit with high energy radiation;
A non-dislocation determination step for determining that the dislocation has been removed based on the dislocation behavior information,
A method for producing a silicon single crystal, which starts the diameter expansion step based on the determination of dislocation-free in the dislocation-free determination step. - 請求項14、15、18及び19の何れか一項に記載のシリコン単結晶製造方法において、
前記高エネルギー放射光が、40keV~70keVの範囲内のエネルギーとされ、0.1rpm~30rpmの範囲の回転速度の回転状態で照射されるシリコン単結晶の製造方法。 The method for producing a silicon single crystal according to any one of claims 14, 15, 18, and 19,
A method for producing a silicon single crystal, wherein the high-energy radiation light has an energy within a range of 40 keV to 70 keV and is irradiated in a rotational state at a rotational speed within a range of 0.1 rpm to 30 rpm. - 前記回転状態において、前記高エネルギー光が照射される前記転位除去部又は前記無転位化部の外周面の照射領域が、前記外周面を周回するように移動する請求項20記載のシリコン単結晶の製造方法。 21. The silicon single crystal according to claim 20, wherein an irradiation region of an outer peripheral surface of the dislocation removing unit or the non-dislocation unit irradiated with the high energy light moves so as to go around the outer peripheral surface in the rotating state. Production method.
- シリコン単結晶をCZ法により引き上げるシリコン単結晶の製造方法において、
シリコン融液に種結晶を接触させ前記シリコン単結晶の引き上げを開始するディップ工程と、
ディップ工程で発生した転位を前記シリコン単結晶の引き上げに従って前記シリコン単結晶の外部方向へ伸展させるか又はループ状に対消滅させて除去し、前記シリコン単結晶に転位除去部又は無転位化部を形成する転位除去工程と、
を有することを特徴とするシリコン単結晶の製造方法。 In the method for producing a silicon single crystal in which the silicon single crystal is pulled by the CZ method,
A dipping step in which a seed crystal is brought into contact with the silicon melt to start pulling up the silicon single crystal;
The dislocations generated in the dip process are removed by extending the silicon single crystal toward the outside according to the pulling of the silicon single crystal or by annihilating it in a loop shape, and dislocation removal or non-dislocation parts are formed in the silicon single crystal. Dislocation removal step to be formed;
A method for producing a silicon single crystal, comprising:
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EP2639342A1 (en) | 2012-03-16 | 2013-09-18 | Siltronic AG | Method of manufacturing silicon single crystal |
JP2013216512A (en) * | 2012-04-05 | 2013-10-24 | Sumco Corp | Method for producing silicon seed crystal and method for producing silicon single crystal |
JP2016519049A (en) * | 2013-05-24 | 2016-06-30 | サンエディソン・セミコンダクター・リミテッドSunEdison Semiconductor Limited | Method for producing low oxygen silicon ingot |
CN112048761A (en) * | 2020-08-24 | 2020-12-08 | 有研半导体材料有限公司 | Large-diameter monocrystalline silicon shouldering growth process |
US20210404087A1 (en) * | 2020-06-29 | 2021-12-30 | Sumco Corporation | Low resistivity wafer and method of manufacturing thereof |
US12031231B2 (en) | 2023-01-25 | 2024-07-09 | Sumco Corporation | Low resistivity wafer |
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DE112010002568B4 (en) * | 2009-06-18 | 2017-01-05 | Sumco Corporation | Method for producing a silicon single crystal |
JP6439536B2 (en) * | 2015-03-26 | 2018-12-19 | 株式会社Sumco | Method for producing silicon single crystal |
US11767611B2 (en) | 2020-07-24 | 2023-09-26 | Globalwafers Co., Ltd. | Methods for producing a monocrystalline ingot by horizontal magnetic field Czochralski |
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EP2639342A1 (en) | 2012-03-16 | 2013-09-18 | Siltronic AG | Method of manufacturing silicon single crystal |
JP2013216512A (en) * | 2012-04-05 | 2013-10-24 | Sumco Corp | Method for producing silicon seed crystal and method for producing silicon single crystal |
JP2016519049A (en) * | 2013-05-24 | 2016-06-30 | サンエディソン・セミコンダクター・リミテッドSunEdison Semiconductor Limited | Method for producing low oxygen silicon ingot |
US10513796B2 (en) | 2013-05-24 | 2019-12-24 | Globalwafers Co., Ltd. | Methods for producing low oxygen silicon ingots |
US20210404087A1 (en) * | 2020-06-29 | 2021-12-30 | Sumco Corporation | Low resistivity wafer and method of manufacturing thereof |
US11598023B2 (en) * | 2020-06-29 | 2023-03-07 | Sumco Corporation | Low resistivity wafer and method of manufacturing thereof |
CN112048761A (en) * | 2020-08-24 | 2020-12-08 | 有研半导体材料有限公司 | Large-diameter monocrystalline silicon shouldering growth process |
CN112048761B (en) * | 2020-08-24 | 2022-02-15 | 有研半导体硅材料股份公司 | Large-diameter monocrystalline silicon shouldering growth process |
US12031231B2 (en) | 2023-01-25 | 2024-07-09 | Sumco Corporation | Low resistivity wafer |
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KR20120027397A (en) | 2012-03-21 |
DE112010002568B4 (en) | 2017-01-05 |
KR101422711B1 (en) | 2014-07-23 |
JPWO2010146853A1 (en) | 2012-11-29 |
JP5804107B2 (en) | 2015-11-04 |
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DE112010002568T5 (en) | 2012-09-13 |
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