Classifications

• • 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
  • C30B15/203—Controlling or regulating the relationship of pull rate (v) to axial thermal gradient (G)
• • 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
• • 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
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S117/00—Single-crystal, oriented-crystal, and epitaxy growth processes; non-coating apparatus therefor
  • Y10S117/911—Seed or rod holders

Definitions

• the present invention relates to a method for producing a single crystal by the Czochralski method, and more particularly to a method for producing a single crystal having a desired defect region and / or a desired defect-free region.
• a single crystal used as a substrate of a semiconductor device includes, for example, a silicon single crystal, and is mainly manufactured by a Czochralski method (Czochra1skiMemethod, hereinafter abbreviated as CZ method).
• the single crystal production apparatus 1 includes a member for accommodating and melting a raw material polycrystal such as silicon, a heat insulating member for shutting off heat, and the like. Housed in two. A pulling chamber 13 extending upward from the ceiling of the main chamber 2 is connected, and a mechanism (not shown) for pulling the single crystal 4 with the wire 5 is provided on the upper part.
• a quartz crucible 7 for accommodating the molten raw material melt 6 and a graphite crucible 8 for supporting the quartz crucible 7 are provided in the main chamber 12, and these crucibles 7 and 8 are rotated by a driving mechanism (not shown). It is supported by the shaft 9 so that it can move up and down freely.
• the drive mechanism of the crucibles 7 and 8 raises the crucibles 7 and 8 by an amount corresponding to the lowering of the liquid level in order to compensate for the lowering of the liquid level of the raw material melt 6 due to the pulling of the single crystal 4.
• a graphite heater 10 for melting the raw material is arranged so as to surround the crucibles 7 and 8. Outside the graphite heater 10, a heat insulating member 11 is provided so as to surround the periphery thereof in order to prevent heat from the graphite heater 10 from being directly radiated to the main chamber 12.
• a cooling cylinder 12 for cooling the pulled single crystal and a graphite cylinder 13 below the cooling cylinder 12 are provided so that the cooling gas can be cooled downstream from the upper part to cool the single crystal.
• a heat insulating material 14 is provided at the lower end of the outside of the graphite cylinder 13 so as to face the raw material melt 6, thereby radiating the radiation from the surface of the raw material melt 6 and keeping the surface of the raw material melt 6 warm.
• the raw material polycrystal is contained in the quartz crucible 7 arranged in the single crystal manufacturing apparatus 1 as described above, and heated by the graphite heater 10 to melt the polycrystalline raw material in the quartz crucible.
• the seed crystal 16 fixed by the seed holder 15 connected to the lower end of the wire 5 is immersed in the raw material melt 6 obtained by melting the polycrystalline raw material as described above.
• a single crystal 4 having a desired diameter and quality is grown below the seed crystal 16.
• a so-called seed drawing necking
• the diameter is once reduced to about 3 mm to form a drawn portion, and then a desired diameter is obtained. It is fattened to the point where the dislocation-free crystals are pulled up.
• Silicon single crystals manufactured by such a CZ method are mainly used for manufacturing semiconductor devices.
• semiconductor devices have been highly integrated, and elements have been miniaturized.
• the problem of Grown-in crystal defects introduced during crystal growth becomes more important.
• the void caused by the aggregation of vacancy-type point defects is known as FPD (Flow Pattern Defect) or COP (Crystal Originated).
• Grown-in defects such as Partic 1e
• the region where these defects exist is called the V (Vacancy) region.
• an OSF (Oxidation Induced Stacking Fault) region is formed in a ring shape from the peripheral force of the crystal due to the decrease in the growth rate. At low speeds, the OSF ring shrinks to the center of the wafer and disappears.
• the dislocation loop is formed by interstitial silicon aggregation.LSEPD (Large Secco Etch Pit Defect) FPD (Large F low P attern Defect) etc. Defects present at low density, this defect exists The region is called the I (lnterstitia 1) region.
• N neutral, Neutral
• Nv region a region with many holes
• Ni region a region with many interstitial silicon
• Cu depot defect regions a region where defects detected by the Cu deposition treatment are remarkably generated. It has been found that this causes deterioration of electrical characteristics such as oxide breakdown voltage characteristics.
• VZG value is the ratio of the pulling rate (V) to the temperature gradient (G) at the solid-liquid interface (for example, VV V oronkov, Journalof Crysta 1 G rowth, 59 (1992), 625-643.).
• VV V oronkov Journalof Crysta 1 G rowth, 59 (1992), 625-643.
• the VZG value when pulling a silicon single crystal, the VZG value is controlled to pull a defect-free single crystal (for example, see Japanese Patent Application Laid-Open No. 11-147886). It is disclosed that an OSF ring or a single crystal having a nucleus in the OSF ring and having a gettering ability is pulled up (for example, see Japanese Patent Application Laid-Open No. 2000-44388). I have. In addition, the VZG value is controlled, and nitrogen is further added to grow a silicon single crystal in the I region (see, for example, Japanese Patent Application Laid-Open No. 11-349394).
• the structure in the furnace (hot zone: HZ) is set so that the temperature gradient G at the solid-liquid interface becomes large.
• HZ hot zone
• the present invention has been made in view of such a problem, and when a VZG value is controlled to pull a single crystal, a VZG value having a desired defect region and a Z or a desired defect-free region is more accurately determined. It is an object of the present invention to provide a method for producing a single crystal that can more reliably pull a single crystal of desired quality.
• the present invention has been made in order to solve the above-mentioned problems, and in a method of producing a single crystal by pulling a seed crystal from a raw material melt by the Chiyoklarski method, the pulling speed when pulling the single crystal is set to V (mm / min), the temperature gradient at the solid-liquid interface is G (K / mm), and the maximum temperature at the interface between the crucible and the raw material melt is Tmax (° C), at least Tmax (° C)
• the range of the V / G value (mm 2 / K ⁇ min) having the desired defect area and / or the desired defect-free area is determined according to the above, and the value of VG (mm 2 / K ⁇ min) is determined in the determined range.
• a method for producing a single crystal characterized in that a single crystal is pulled under control.
• the range is determined by correcting the value of the V / G value (mm 2 / K ⁇ min) having the desired defect area and Z or the desired defect-free area at least according to Tmax (° C). and, by controlling the value of VZG (mm 2 / K ⁇ min ) in the range the determined pulling a single crystal, VZG value having a desired defect region and or a desired defect-free region (mm 2 / ⁇ min ) Can be determined more accurately, so that the desired defect area And / or the single crystal in the defect-free region can be more reliably pulled.
• the temperature gradient G (K / mm) at the solid-liquid interface is the temperature gradient between the melting point of the raw material (141 2 ° C for silicon) and 1400 ° C.
• the control of the V / G value (mm 2 K 'min) refers to the control of the V / G value over almost the entire area in the radial direction of the crystal (excluding the outer peripheral region of 0 to 2 cm, which is the outward diffusion region). To tell.
• the VZG value (mm 2 / K ′ min) is set to a value of ⁇ 0.00.07 2 4 XT max +1.3 1 or more and less than 0.0 00 7 24 XTmax + l.38.
• a single crystal can be pulled by controlling the range.
• the V / G value (mm 2 / Kmin) should be less than _0.00.07 24 XTmax + 1.3 1-less than 0.00.07 24 XTmax + l.38
• the V / G value (mm 2 / K ⁇ min) should be not less than 0.000 7 2 4 X Tmax + 1.3 1-0.000 7 24 XTmax + l. 3 7
• the single crystal can be pulled by controlling the V / G value (mm 2 ZK ′ min) in the range of ⁇ 0.00.072 4 XT max +1.38 or more.
• VZG value (mm 2 / K ′ min) is calculated as 0.00.07 2 4 X
• a single crystal without the F ring can be manufactured.
• the V / G value (mmSZK'min) is set to -0.00.07 2 4 XT max +1.31 or more -0.00.07 24 XTmax + l.35 or less.
• a single crystal can be pulled by controlling the range.
• Ni will this Yo, VZG value (mm 2 ZK 'min), one 0. 0 0 0 7 24 XTm a X + 1. 3 1 over a 0. 0 0 0 7 24 XTm ax + l. 3 5 following Control to range Then, by pulling the single crystal, a single crystal having an N region without a Cu depot defect region can be reliably manufactured.
• the single crystal by setting the Tmax (° C) to a range of 156 ° C or less.
• the V and G values can be made sufficiently large. Accordingly, the pulling speed V (mm / min) when pulling a single crystal having a desired defect region and Z or a desired defect-free region can be sufficiently increased, and the productivity of the single crystal can be sufficiently increased. it can.
• the Tmax (° C.) is set at least by providing a heat insulating material between a crucible accommodating the raw material melt and a heater arranged so as to surround the crucible, or at the bottom of the crucible. This can be changed by providing a heat insulating material.
• Tmax (° C) can be changed to the desired temperature.
• the single crystal can be silicon.
• the diameter of the single crystal can be 20 O mm or more.
• the method for producing a single crystal of the present invention is particularly effective for producing a single crystal having a diameter of 200 mm or more, for which demand has been increasing in recent years and quality requirements have become strict.
• the single crystal produced by the method for producing a single crystal of the present invention is of high quality.
• FIG. 1 is a schematic cross-sectional view of a single crystal manufacturing apparatus in which a heat insulating material is provided on the bottom and side surfaces of a crucible.
• FIG. 2 is a schematic sectional view of an ordinary single crystal manufacturing apparatus.
• FIG. 3 is a graph showing the range of VZG values and Tmax of a single crystal in a desired defect region and / or a defect-free region.
• FIG. 4 is a graph showing the relationship between the V / G value at the boundary between the NV region and the Ni region and Tmax (° C).
• FIG. 5 is an explanatory diagram showing a growth rate and a crystal defect distribution.
• FIG. 6 is a graph showing the relationship between the V-no G value at the boundary between the NV region and the Ni region and the crucible diameter.
• the present inventors have conducted intensive studies using experiments and simulations, and as a result, the predicted V / G value differs from the actual VZG value, for example, a single crystal with the same defect distribution,
• the desired defect is generated in various types of furnace structures (hot zone: HZ). It has been found that when pulling a single crystal in a region and / or a desired defect-free region, VZG values having the region differ depending on each HZ.
• the present invention relates to a method for producing a single crystal by pulling a seed crystal from a raw material melt by the Czochralski method, wherein the pulling speed for pulling the single crystal is V (mm / min), the solid-liquid interface (raw material The melting point of the melting point to 140 ° C) is G (K / mm), and the maximum temperature at the interface between the crucible and the raw material melt is Tmax (° C).
• the present invention provides a method for producing a single crystal, characterized in that the value is controlled over almost the entire area in the radial direction of the crystal (excluding the outer periphery of 0 to 2 cm) to pull up the single crystal.
• This Tmax (° C) can be obtained, for example, by arranging thermocouples at intervals of 2 cm from the bottom of the crucible to the outer periphery, measuring the temperature, and calculating by simulation. You can also ask.
• FIG. 4 is a graph showing the relationship between the V / G value at the boundary between the NV region and the Ni region and Tmax (° C).
• the VZG value and Tmax (° C) have a clear correlation, and are extremely useful parameters for determining the V / G value having the desired defect area and Z or the desired defect-free area. It turns out that there is. That is, in order to determine the VZG value to be controlled, it is necessary to perform correction by Tmax (° C).
• V / G value (mm 2 / K ⁇ min) having the desired defect area and / or the desired defect-free area can be determined more accurately according to each of various HZs, Even if a device having HZ is used, crystals of desired quality can be obtained efficiently, and it is also useful when designing a single crystal manufacturing device.
• FIG. 3 shows the results of a more detailed investigation of the range of the VZG value and Tmax of the single crystal of the desired defect area and Z or the non-defect area.
• FIG. 3 (a) is a graph showing the range of VZG values and Tmax serving as the N region and the OSF region.
• FIG. 3 (b) is a graph showing the range of VZG values and Tmax, which are V regions.
• FIG. 3 (c) is a graph showing the range of the VZG value and the Tmax of the N region without the Cu depot defect region.
• the VZG value (mm 2 K.min) is set to 0.00 0 7 2 4 XTm ax + l.
• the V / G value (mm 2 ZK 'min) is set to — 0.0 0 0 7 2 4 X Tmax +1.31 or more—0.0 0 0 7 24 XT max +1.37
• the VG value (mm 2 / K ⁇ min) was controlled to a range of -0.00.072 4 X Tmax + l.3.8 or more. in pulling Rukoto the single crystal, ensures further can be produced the OSF-ring outwardly exclusion monocrystalline, sea urchin I is apparent from FIG. 3 (c), VG value (mm 2 ZK ⁇ min) , — 0.0 0 0 7 2 4 X Tmax + l. 3 1 or more — 0.0 0 0 7 2 4 X Tmax + 1.35 Thus, a single crystal having an N region having no Cu deposit defect region can be produced more reliably.
• V / G value (mm 2 ZK.min) can be made sufficiently high.
• Tmax (° C) is set to 1560 ° C or less
• VZG value (mm 2 ZK.min) at the boundary between the I region and the N region can be obtained.
• the maximum temperature Tma X (° C) at the interface between the crucible and the raw material melt can be changed by changing HZ.
• At least a crucible that contains the raw material melt and a crucible that surrounds the crucible can be changed by providing a heat insulating material between the heater and the heater, or by providing a heat insulating material on the bottom of the crucible.
• This single crystal manufacturing apparatus 1 is almost the same as the single crystal manufacturing apparatus shown in FIG. 2 except that a heat insulating material 17 is provided on the bottom and side surfaces of the crucible. That is, here, in the single crystal manufacturing apparatus 1, the single crystal 4, the raw material melt 6, the quartz crucible 7, the graphite crucible 8, the shaft 9, the graphite heater 10, the heat insulating member 1 in the main champer 2 1, graphite tube 13, heat insulation material 14, and crucible heat insulation material 17 are shown. Of these, Tma X (° C) can be changed to a desired range by changing the number, size, position, material, and the like of the crucible heat insulating material 17.
• Tmax (° C) can also be changed by changing the size of the Norrebo. For example, if the size of the crucible is made smaller, the Tmax (° C) can be made lower, and therefore, as shown in FIG. 6, by reducing the size of the crucible, the desired defect area and Z or the desired defect-free area can be reduced.
• the VZG value having the above can be set higher.
• the size of the crucible for example, larger than the diameter of the single crystal to be pulled and less than or equal to 2.5 times, the Tmax (° C) can be sufficiently reduced, and thus the desired defect area can be reduced.
• / or the VZG value having the desired defect-free region can be set to a sufficiently high range.
• the single crystal manufacturing method of the present invention has been increasingly diversified in single crystal manufacturing equipment in recent years, and it has become difficult to accurately predict a VZG value having a desired defect region and Z or a desired defect-free region.
• it is particularly suitable for producing silicon single crystals, which have strict quality requirements.
• the method for producing a single crystal of the present invention is particularly effective for producing a single crystal having a diameter of 200 mm or more, for which demand has been increasing in recent years and quality requirements have become strict.
• a silicon single crystal with a diameter of 8 inches (200 mm) was entirely deposited at the Cu depot defect area. It was decided to raise it so that there was no N area.
• VZG value (mm 2 ZK. Min) range, 0.2 4 below 0.2 more taking the safety of The range was decided.
• the single crystal was pulled under the control of the determined V / G value (mm 2 ZK ′ min).
• the pulling speed V was 0.51 mm / min or more and 0.56 mm Controlled to within / min and pulled up.
• the silicon single crystal pulled in this way was an N region without any Cu depot defect region, and was of excellent quality.
• Example 2 Using the same single crystal manufacturing apparatus as in Example 1, a silicon single crystal having a diameter of 8 inches (200 mm) was pulled up so as to be an N region having no Cu depot defect region over the entire surface. However, no heat insulator was provided to change the maximum temperature TmaX (° C) at the interface between the crucible and the raw material melt.
• the maximum temperature Tmax (° C) at the interface between the crucible and the raw material melt was 156 ° C. From this Tmax (° C), in order to manufacture a single crystal having an N region without a Cu depot defect region, the range of the V / G value (mm 2 ZK'min) must be 0.18 or more. 0.22 or less (—0.00.07 2 4 X 15 6 0 + 1.31 or more -0.0.0.07 2 4 X15 6 0 + 1.35 or less). Therefore, in order to pull up a single crystal that is an N region without Cu depot defects on the entire surface, the range of V / G value (mm 2 ZK'min) should be set to 0.19 or more in view of safety.
• the range was determined to be 0.21 or less.
• the single crystal was pulled while controlling to the range of the determined VZG value (mm 2 ZK * min). That is, in the HZ of this single crystal manufacturing apparatus, since the temperature gradient G of the solid-liquid interface was 2.500 K / mm, the pulling speed V was set to 0.48 mm / min or more and 0.53 mm Controlled to within / min or lower.
• the silicon single crystal pulled in this way was an N region without any Cu depot defect region, and was of excellent quality.
• the range of V / G value (mm 2 ZK 'min) should be 0.16 or more in view of safety. It was determined to be in the range below 0.18. Next, the determined VZG value (mm ⁇ The single crystal was pulled within the range of (min).
• the temperature gradient G at the solid-liquid interface was 2.674 KZmm, so the pulling speed V was 0.43 mm / min or more and 0.48 mm / min or less. Controlled within the range of pulling. As a result of inspection, the silicon single crystal pulled in this way was an N region without any Cu depot defect region, and was of excellent quality.
• Example 4 Using the same single-crystal manufacturing apparatus as in Example 1, the silicon single crystal having a diameter of 8 inches (200 mm) was not removed from the entire surface without a defect-free region, but the OSF ring was excluded to the outside, and the crystal was removed. It was decided to pull up so that almost the entire surface in the radial direction was in the V region. However, the single crystal manufacturing apparatus used here was designed so that the distance between the surface of the raw material melt 6 and the lower end of the heat insulating material 14 was half that of the single crystal manufacturing apparatus of Example 1. The position of 14 was adjusted.
• the maximum temperature Tmax (° C) at the interface between the crucible and the raw material melt was 1514 ° C. From this Tmax (° C), in order to produce a single crystal in which almost the entire surface in the radial direction of the crystal has a V region, the range of the V / G value (mm 2 ZK ⁇ min) must be 0.28 or more. (—0.00.07 24 X15 14 + 1.38 or more). In addition, the VZG value (mm 2 / K 'min) is within the range where single crystals can be grown without being deformed. 1.90 or less (—0.00.07 24 X15 14 +3.0 or less) ).
• the range of the VZG value (mm 2 / K The following range was determined.
• the single crystal was pulled under the control of the determined VZG value (mm 2 ZK ′ min).
• the pulling speed V was 1.18 mmZm in or more and l.26 mmZm Controlled within the range of in or less.
• the present invention a method of manufacturing a single crystal in which impurities such as nitrogen and carbon are not added (non-doped) has been described.
• impurities such as nitrogen and carbon are added
• the VZG value is larger than that of non-doped.
• T max correction it is possible to add T max correction to the VZG value for each impurity and the defect region that changes with their concentration. It is included in the scope of the present invention.

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• 2003
  • 2003-05-13 JP JP2003135085A patent/JP4151474B2/ja not_active Expired - Fee Related
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