JP2005206391A - Method for guaranteeing resistivity of silicon single crystal substrate, method for manufacturing silicon single crystal substrate, and silicon single crystal substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for guaranteeing the resistivity of a silicon single crystal substrate, by which the accurate resistivity of a silicon single crystal substrate for a product can be guaranteed in a CZ silicon single crystal substrate in which nitrogen is added, and to provide a method for manufacturing the silicon single crystal substrate, and a silicone single crystal substrate. <P>SOLUTION: The method for guaranteeing the resistivity of the silicon single crystal substrate comprises: at least adding nitrogen to a silicon single crystal rod when the silicon single crystal rod is grown by a CZ method; cutting silicon single crystal substrates for inspection from both ends of the constant diameter cylindrical part of a grown silicon single crystal rod; then heat-treating the cut silicon single crystal substrates for inspection by keeping them at a temperature of 800°C to the melting point of silicon at least before the semiconductor element manufacturing process; measuring the resistivity of each silicon single crystal substrate for inspection, subjected to the heat treatment; and utilizing the measured resistivity of the silicon single crystal substrates for inspection as the certification value of the resistivity of each silicon single crystal substrate for a product, which is cut from the remaining part of the constant diameter cylindrical part of the grown silicon single crystal rod. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a resistivity guarantee method for a silicon single crystal substrate that is grown by the Czochralski method (CZ method) and to which nitrogen is added, a method for manufacturing a silicon single crystal substrate to which nitrogen is added, and a silicon single crystal substrate. .

  2. Description of the Related Art In recent years, in the manufacture of semiconductor devices, quality requirements for silicon single crystals (CZ silicon single crystals) grown by the CZ method have increased as circuit elements have become finer due to higher integration of semiconductor circuits. Yes. In particular, in a CZ silicon single crystal, FPD (Flow Pattern Defect), LSTD (Laser Scattering Tomography Defect), COP (Crystal Originated Particle), etc. are called Grown-in defects, and the oxide film withstand voltage characteristics and device characteristics are called. Defects due to single crystal growth that deteriorate are present, and their reduction is regarded as important.

  Therefore, we improved the growth conditions of the epitaxial substrate in which a new silicon layer was epitaxially grown on a normal silicon single crystal substrate, the annealed substrate annealed at a high temperature in a hydrogen and argon atmosphere, and the CZ silicon single crystal. Several single-crystal substrates with few grown-in defects have been developed, such as a full-surface N region (region outside the OSF ring and no dislocation cluster) substrate.

  Among these, a substrate obtained by performing annealing heat treatment on a nitrogen-doped substrate to which nitrogen is added (doped) (hereinafter sometimes referred to as a nitrogen-doped annealing substrate) has reduced Grown-in defects in the substrate surface layer portion, and A BMD (Bulk Micro Defect) density in the bulk is also very useful as a substrate. This is a substrate developed using the growth-in defect aggregation suppressing effect and oxygen precipitation promoting effect of nitrogen doping, and the defect size is smaller than that of a normal crystal. Since the BMD density in the bulk is high, the substrate has an effective gettering ability.

  On the other hand, at the time of silicon single crystal growth, for example, in order to suppress dislocation generation due to thermal stress generated in the silicon single crystal substrate during heat treatment in a high temperature region of 1000 ° C. or higher, or to prevent generation of crystal defects during single crystal growth. It is also known to add nitrogen.

  However, it is known that when the silicon single crystal substrate to which nitrogen is added in this way is subjected to heat treatment, the resistivity of the substrate changes from the value before the heat treatment. For this reason, if the silicon single crystal substrate to which nitrogen is added is subjected to the heat treatment during the manufacturing process of the semiconductor element as described above, the resistivity of the substrate changes and the characteristics of the semiconductor element to be manufactured also change. There was an unfavorable problem that it would end up.

  For such problems, at least before the semiconductor element manufacturing process, for example, a silicon single crystal substrate grown by the floating zone method (FZ method) is subjected to a heat treatment at a temperature of 900 to 1250 ° C. for about 10 to 60 minutes. Thus, a method of manufacturing a silicon single crystal substrate whose resistivity does not change even by a heat treatment performed in a semiconductor element manufacturing process is disclosed (for example, see Patent Document 1).

In addition, regarding the CZ silicon single crystal, since a quartz crucible is used when growing the single crystal, quartz on the inner wall of the crucible is eluted and oxygen atoms are mixed into the silicon single crystal. When a low temperature heat treatment of about 350 to 500 ° C. is performed during the cooling step after the growth of the silicon single crystal, a plurality of oxygen atoms gather to form an electrically active oxygen donor (thermal donor), There is also a problem that the target resistivity cannot be obtained or the resistivity is changed by a heat treatment in a subsequent semiconductor element manufacturing process.
In order to prevent this problem, heat treatment for erasing the oxygen donor has been conventionally performed. Usually, this oxygen donor erasure is performed by heat-treating a silicon single crystal substrate at a temperature of 650 ° C. to 700 ° C. for 10 minutes to 1 hour in an inert gas atmosphere.

  In addition, in a CZ silicon single crystal substrate, a silicon single crystal substrate having a resistivity of 100 Ω · cm or more is formed at a temperature range of 1000 to 1200 ° C. in an atmosphere of hydrogen gas and / or argon gas for the purpose of enhancing gettering capability. A method for suppressing fluctuation in resistivity by performing heat treatment for ˜20 hours to precipitate oxygen and lowering the interstitial oxygen concentration to 8 ppma or less to reduce the influence of oxygen donor formation (for example, Patent Document 2).

  In the above Patent Document 1 and Patent Document 2, in the crystal grown by either the FZ method or the CZ method, the resistivity variation of the high resistance crystal having a resistivity exceeding 100 Ω · cm increases, Is disclosed.

  On the other hand, the threshold voltage Vth of a semiconductor element manufactured using the silicon single crystal substrate having a resistivity of about 20 Ω · cm, which has been in high demand in recent years, may deviate from the design value. There may be a problem in the characteristic design of the semiconductor element.

Japanese Patent No. 2742247 JP 2002-1000063 A

  The present invention relates to a silicon single crystal substrate resistivity guarantee method and a silicon single crystal substrate resistance guarantee method capable of accurately guaranteeing the resistivity of a product silicon single crystal substrate in a CZ silicon single crystal substrate to which nitrogen is added. It is an object to provide a manufacturing method and a silicon single crystal substrate.

  In order to achieve the above object, the present invention is a method for guaranteeing the resistivity of a silicon single crystal substrate, and at least when the silicon single crystal rod is grown by the Czochralski method, nitrogen is added to the silicon single crystal rod. In addition, a silicon single crystal substrate for inspection is cut from both ends of a straight cylindrical portion of the grown silicon single crystal rod, and the cut silicon single crystal substrate for inspection is at least 800 ° C. to silicon before the semiconductor element manufacturing process. And holding the heat treatment at any temperature between the melting points of the silicon, measuring the resistivity of the heat-treated test silicon single crystal substrate, and measuring the measured resistivity value of the test silicon single crystal substrate Maintaining the resistivity of a silicon single crystal substrate, which is used as a guaranteed value of the resistivity of a silicon single crystal substrate for a product that is cut from the remaining portion of the straight cylindrical portion of the single crystal rod A method (claim 1).

  In this way, a silicon single crystal substrate for inspection is cut out from both ends of the straight cylindrical portion of the silicon single crystal rod grown by the CZ method by adding nitrogen, and may be simply described as a substrate for inspection hereinafter. These inspection substrates are heat-treated at least at a temperature between 800 ° C. and a melting point of silicon (1420 ° C.), preferably 900 ° C. to 1250 ° C., at least before the semiconductor element manufacturing process, and then the inspection substrate. The resistivity after the donor action of not only oxygen but also added nitrogen and nitrogen-oxygen mixture is eliminated by heat treatment can be measured. The resistivity obtained with the inspection substrate thus measured does not change greatly even if heat treatment is performed in an annealing process for forming a defect-free (DZ) layer on the substrate surface or a process for manufacturing a semiconductor element. Therefore, the measured resistivity of the inspection substrate may be referred to as a product silicon single crystal substrate (hereinafter referred to as a product substrate) from the remaining portion of the straight cylindrical portion of the silicon single crystal rod after the inspection substrate is cut out. ) Is used as a guaranteed value of the resistivity of the product substrate, it is possible to guarantee the resistivity of the product substrate accurately.

In this case, it is preferable that the initial interstitial oxygen concentration of the grown silicon single crystal rod is 8 to 20 ppma.
Thus, when the initial interstitial oxygen concentration of the silicon single crystal rod is 8 to 20 ppma (JEIDA: Japan Electronics Industry Promotion Association standard), high-quality silicon single crystal having high mechanical strength and adequately gettering ability. It becomes a crystal.
Further, if the oxygen concentration is 8 ppma or more, the contribution of oxygen to the resistivity as a donor is large. Therefore, the effect of suppressing the change in resistivity can be enhanced by performing a heat treatment that eliminates the action, and the resistance according to the present invention. A more accurate resistivity guarantee is possible by the rate guarantee method.

The nitrogen concentration of the silicon single crystal rod to be grown is preferably 1 × 10 ^{13 to} 5 × 10 ¹⁵ pieces / cm ³ (Claim 3).
Thus, when the nitrogen concentration of the silicon single crystal rod is 1 × 10 ¹³ pieces / cm ³ or more, the effect of promoting oxygen precipitation by doping nitrogen is clear, and 5 × 10 ¹⁵ pieces / cm ³ or less. If this is the case, there will be no hindrance to single crystallization at the time of pulling up the single crystal, or destabilization of continuous operation.
Further, if the nitrogen concentration is 1 × 10 ¹³ atoms / cm ³ or more, since the contribution to the resistivity as nitrogen donor is large, the effect of suppressing the change in resistivity is higher by performing heat treatment to eliminate the action. Therefore, the resistivity measurement method according to the present invention enables more accurate resistivity guarantee.

The resistivity of the silicon single crystal rod to be grown is preferably 10 Ω · cm or more.
Thus, when the resistivity of the silicon single crystal rod is set to 10 Ω · cm or more, the influence of donors by oxygen, nitrogen, and a nitrogen-oxygen mixture on the resistivity becomes significant. The effect of erasing the influence by heat treatment at a certain temperature is increased.

Moreover, it is preferable that the atmosphere of the heat treatment performed on the silicon single crystal substrate for inspection is an atmosphere containing at least one of oxygen, nitrogen, hydrogen, and argon.
As described above, when the atmosphere of the heat treatment performed on the inspection substrate is an atmosphere containing at least one of oxygen, nitrogen, hydrogen, and argon, the oxygen, nitrogen, and nitrogen oxygen mixture in the inspection silicon single crystal substrate is used. Therefore, the resistivity can be guaranteed more accurately and quickly thereafter. The oxygen atmosphere may be wet or dry, and may be an atmosphere in which oxygen and nitrogen, nitrogen and hydrogen, nitrogen and argon, or hydrogen and argon are mixed.

The heat treatment performed on the silicon single crystal substrate for inspection is preferably performed using a resistance heating furnace or a rapid heating furnace.
As described above, when the heat treatment performed on the inspection substrate is performed using a resistance heating furnace or a rapid heating furnace, the heat treatment for eliminating the action as a donor of oxygen, nitrogen, and a nitrogen-oxygen mixture in the inspection silicon single crystal substrate. Therefore, the resistivity can be guaranteed more accurately and quickly thereafter.

Further, it is preferable that the heat treatment performed on the silicon single crystal substrate for inspection is performed for 10 seconds to 120 minutes.
As described above, if the heat treatment performed on the inspection substrate is performed for 10 seconds to 120 minutes, the action as a donor of the oxygen, nitrogen, and nitrogen-oxygen mixture in the inspection silicon single crystal substrate can be sufficiently performed. Then, the resistivity can be guaranteed more accurately and quickly.

  The present invention is also a method for producing a silicon single crystal substrate, and at least when growing a silicon single crystal rod by the Czochralski method, nitrogen is added to the silicon single crystal rod, and the grown silicon The silicon single crystal substrate for inspection is cut from both ends of the straight cylindrical portion of the single crystal rod, and the cut silicon single crystal substrate for inspection is held at any temperature between 800 ° C. and the melting point of silicon for heat treatment. And measuring the resistivity of the heat-treated test silicon single crystal substrate, and when the measured resistivity value of the test silicon single crystal substrate is within a predetermined standard range, A method for producing a silicon single crystal substrate is provided, wherein the product silicon single crystal substrate is cut from the remaining portion of the body cylindrical portion.

  Thus, the inspection substrate is cut out from both ends of the straight cylindrical portion of the silicon single crystal rod grown by the CZ method by adding nitrogen, and the inspection substrate is heated to 800 ° C. to the melting point of silicon (1420 ° C.), preferably Is maintained at any temperature between 900 ° C. and 1250 ° C. and heat-treated, and then the resistivity of the inspection substrate is measured, oxygen in the inspection silicon single crystal substrate, added nitrogen, and nitrogen-oxygen mixture It is possible to measure the resistivity after the donor action is eliminated by heat treatment. The resistivity of the substrate thus measured does not change greatly even if heat treatment is performed in an annealing process for forming a DZ layer on the substrate surface or a process for manufacturing a semiconductor element. Therefore, when the measured value of the resistivity of the inspection substrate is within a predetermined standard range, if the product substrate is cut out from the remaining portion of the straight cylindrical portion of the silicon single crystal rod, the subsequent semiconductor element It becomes possible to provide a silicon single crystal substrate in which the resistivity value is guaranteed to be within the standard range by heat treatment in a manufacturing process or the like.

In this case, it is preferable that the cut silicon single crystal substrate for product is heat-treated at least at a temperature between 800 ° C. and the melting point of silicon at least before the semiconductor element manufacturing process.
In this way, the cut product substrate is heat-treated at least at a temperature between 800 ° C. and the melting point of silicon (1420 ° C.), preferably between 900 ° C. and 1250 ° C., at least before the semiconductor element manufacturing process. For example, it is possible to provide a silicon single crystal substrate having a resistivity within the standard range guaranteed by the inspection substrate.

The initial interstitial oxygen concentration of the silicon single crystal rod to be grown is preferably 8 to 20 ppma.
Thus, when the initial interstitial oxygen concentration of the silicon single crystal rod is 8 to 20 ppma, a high-quality silicon single crystal having a high mechanical strength and an appropriate gettering ability is obtained. Further, if the oxygen concentration is 8 ppma or more, the contribution of oxygen to the resistivity as a donor is large. Therefore, the effect of suppressing the change in resistivity becomes higher by performing a heat treatment that eliminates the action, and the production according to the present invention. By the method, it is possible to provide a silicon single crystal substrate having a more stable and stable resistivity.

The nitrogen concentration of the silicon single crystal rod to be grown is preferably 1 × 10 ^{13 to} 5 × 10 ¹⁵ pieces / cm ³ .
Thus, when the nitrogen concentration of the silicon single crystal rod is 1 × 10 ¹³ pieces / cm ³ or more, the effect of promoting oxygen precipitation by doping nitrogen is clear, and 5 × 10 ¹⁵ pieces / cm ³ or less. In this way, there is no hindrance to single crystallization at the time of pulling up the single crystal, or destabilization of continuous operation. Further, if the nitrogen concentration is 1 × 10 ¹³ atoms / cm ³ or more, since the contribution to the resistivity as nitrogen donor is large, the effect of suppressing the change in resistivity is higher by performing heat treatment to eliminate the action. Thus, the manufacturing method according to the present invention can provide a silicon single crystal substrate having a more stable and stable resistivity.

The resistivity of the silicon single crystal rod to be grown is preferably 10 Ω · cm or more.
As described above, when the resistivity of the silicon single crystal rod is 10 Ω · cm or more, the influence of the donor due to oxygen, nitrogen, and the nitrogen-oxygen mixture becomes significant. The effect of erasing the influence by heat treatment is increased.

Moreover, it is preferable that the atmosphere of the heat treatment performed on the silicon single crystal substrate for inspection or product is an atmosphere containing at least one of oxygen, nitrogen, hydrogen, and argon.
Thus, if the atmosphere of the heat treatment performed on the silicon single crystal substrate for inspection or product is an atmosphere containing at least one of oxygen, nitrogen, hydrogen, and argon, the silicon single crystal substrate for inspection or product Since the action of oxygen, nitrogen, and nitrogen-oxygen mixture as a donor can be effectively eliminated, a silicon single crystal substrate with a guaranteed resistivity can be manufactured more accurately and rapidly thereafter. The oxygen atmosphere may be wet or dry, and may be an atmosphere in which oxygen and nitrogen, nitrogen and hydrogen, nitrogen and argon, or hydrogen and argon are mixed.

Moreover, it is preferable to perform the heat treatment performed on the inspection or product silicon single crystal substrate using a resistance heating furnace or a rapid heating furnace.
Thus, if the heat treatment performed on the silicon single crystal substrate for inspection or product is performed using a resistance heating furnace or a rapid heating furnace, oxygen, nitrogen, and a nitrogen-oxygen mixture in the silicon single crystal substrate for inspection or product Since the heat treatment that eliminates the donor action can be effectively performed, a silicon single crystal substrate with a guaranteed resistivity can be manufactured more accurately and rapidly thereafter.

Moreover, it is preferable to perform the heat treatment performed on the silicon single crystal substrate for inspection or product for 10 seconds to 120 minutes.
Thus, if the heat treatment performed on the silicon single crystal substrate for inspection or product is performed for 10 seconds to 120 minutes, it acts as a donor of oxygen, nitrogen, and a mixture of nitrogen and oxygen in the silicon single crystal substrate for inspection or product. Since the erasing can be sufficiently performed, a silicon single crystal substrate whose resistivity is guaranteed more accurately and rapidly can be manufactured thereafter.

The present invention also provides a silicon single crystal substrate manufactured by any one of the methods described above (claim 16).
Thus, in the case of a silicon single crystal substrate manufactured by any of the above-described methods, nitrogen doped CZ in which the resistivity value is reliably guaranteed to be within the standard range by the heat treatment in the semiconductor element manufacturing process or the like. A silicon single crystal substrate, which has a high resistivity and threshold voltage stability of a semiconductor device manufactured using the silicon single crystal substrate as a substrate, is suitable for manufacturing a highly accurate semiconductor device with an operating standard, and has very few crystal defects on the substrate surface layer. A high-quality silicon single crystal substrate can be obtained.

In this case, it is preferable that the silicon single crystal substrate has a diameter of 150 mm or more.
Thus, if the diameter of the silicon single crystal substrate is a large diameter of 150 mm or more, it is suitable for manufacturing a high-quality semiconductor element with a high yield, and in particular, a large-diameter substrate having a diameter of 200 mm or 300 mm, which has recently been increasing in demand. It can be.

In accordance with the present invention, an inspection substrate is cut out from both ends of a straight cylindrical portion of a silicon single crystal rod that is grown by CZ method by adding nitrogen, and the inspection substrate is made of silicon at least from 800 ° C. before the semiconductor element manufacturing process. The melting point (1420 ° C.), preferably at a temperature between 900 ° C. and 1250 ° C., is heat-treated, and then the resistivity of the inspection substrate is measured. When the product silicon single crystal substrate is cut out from the remaining portion of the crystal rod, if it is used as the guaranteed value of the resistivity of the product substrate, it is possible to guarantee the resistivity of the product substrate accurately.
Further, when the measured resistivity value of the inspection substrate is within a predetermined standard range, the product silicon single crystal substrate is cut out from the remaining portion of the straight cylindrical portion of the silicon single crystal rod. For example, it is possible to provide a silicon single crystal substrate in which the resistivity value is reliably guaranteed to be within the standard range by the subsequent heat treatment.

Hereinafter, although this invention is explained in full detail, this invention is not limited to this.
As described above, the threshold voltage Vth of an actually manufactured semiconductor device may deviate from the design value even in the case of a silicon single crystal substrate having a resistivity of about 20 Ω · cm, which has been in high demand in recent years. In some cases, there were problems in characteristic design.

  The inventors of the present invention have caused the deviation of the threshold voltage from the design value due to the deviation of the resistivity of the actual silicon single crystal substrate and the guaranteed value of the resistivity used in designing the semiconductor element. I found out.

  The silicon single crystal substrate in which the resistivity shift occurs as described above is manufactured from a CZ silicon single crystal to which nitrogen is added. When measuring a guaranteed value of resistivity, the inert gas atmosphere is used. The heat treatment was performed at 650 ° C. for 20 minutes to eliminate the oxygen donor. Therefore, the present inventors have considered that the occurrence of such a deviation in resistivity is mainly caused by a nitrogen oxygen mixture donor (NO donor) remaining in the substrate.

Therefore, the following experiment was performed in order to obtain heat treatment conditions for erasing these donors.
(Experiment)
A silicon single crystal rod having a diameter of 200 mm, an oxygen concentration of 14 ppma (JEIDA), a nitrogen concentration of 5 × 10 ¹³ pieces / cm ³ and a resistivity of 20 Ω · cm (target value) was grown by the CZ method. A plurality of silicon single crystal substrates prepared by slicing a straight cylindrical portion of the silicon single crystal rod are prepared, and heat treatment is performed by resistance heating in an argon atmosphere at a temperature of 650 ° C. for 20 minutes in order to erase the oxygen donor. The resistivity (ρ1) at this time was measured in a furnace. Thereafter, in order to erase the NO donor, heat treatment is performed for 15 seconds at a temperature in the range of 650 ° C. to 1200 ° C. in a rapid heating furnace in an argon atmosphere, and the resistivity (ρ 2) of each of the substrates heat-treated at each temperature. ) Was measured.

FIG. 1 is a graph showing the difference between the heat treatment temperature for the NO donor erasure and the resistivity before and after the heat treatment (Δ (ρ2−ρ1)), that is, the effect of NO donor erasure. From this, the resistivity difference becomes large by heat treatment at 800 ° C., more preferably 900 ° C. or more, and the NO donor is erased, and if it is 900 ° C. or more, the resistivity difference is almost constant, and the effect of donor erasure Was found to be uniform.
When a similar experiment was conducted on a silicon single crystal substrate having a resistivity of 10 Ω · cm (target value), ρ1 was about 9.83 Ω · cm, ρ2 was about 9.73 Ω · cm, and the difference was −0. 10 Ω · cm. From this, it is considered that the influence of the NO donor becomes remarkable at 10 Ω · cm or more.

Further, FT-IR spectrum measurement was performed to confirm that NO donors exist in the silicon single crystal substrate and NO donors that are not erased by the heat treatment for erasing oxygen donors are erased by the heat treatment.
FIG. 2 shows a substrate manufactured under the same conditions as in the above experiment, the substrate (B) subjected to heat treatment for oxygen donor erasure, and then heat treated at 1200 ° C. for 1 hour in a resistance heating furnace for erasing NO donor. Is the FT-IR spectrum of the substrate (C) subjected to the above, wherein the horizontal axis indicates the wave number and the vertical axis indicates the absorbance. For comparison, the FT-IR spectrum of a substrate (A) obtained by performing a heat treatment for oxygen donor erasing on a substrate manufactured under the same conditions as in the above experiment except that the resistivity was set low and nitrogen was not added was also measured. .

The peak at about 245 cm ^{−1 in} the figure is a peak due to absorption of boron which is a dopant for adjusting the resistivity. Although the position of about 240 cm ^-1 and 250 cm ^-1 indicated by the arrow is the position of the absorption of NO donors, absorption of the substrate only NO donor (B), which was more remarkable especially in 250 cm ^-1.
As a result, the NO donor is not present in the substrate to which nitrogen is not added, and the NO donor that is not erased by the heat treatment for erasing the oxygen donor is erased by the heat treatment at 1200 ° C. for 1 hour for the subsequent NO donor erase. It shows that.

  Based on these experimental results, the present inventors diligently studied a method for guaranteeing the resistivity of a nitrogen-added CZ silicon single crystal substrate and completed the present invention.

Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited thereto. First, an example of the resistivity guarantee method for a silicon single crystal substrate according to the present invention will be specifically described.
First, a known CZ method for growing a single crystal rod having a desired diameter by bringing a seed crystal into contact with a melt of a polycrystalline silicon raw material housed in a rotating quartz crucible and slowly rotating the seed crystal while rotating it, or In this CZ method, a silicon single crystal rod is grown by a known MCZ method in which a magnetic field is applied to a silicon melt to control the convection of the melt to pull up the single crystal.

At this time, nitrogen is added to the silicon single crystal rod to be grown. Nitrogen is added by, for example, introducing a nitride such as a silicon substrate on which a nitride film is formed in advance into a raw material polycrystal of a quartz crucible. This can be done easily. At this time, it is preferable to introduce nitride so that the nitrogen concentration is 1 × 10 ^{13 to} 5 × 10 ¹⁵ atoms / cm ³ . The amount of nitride necessary to obtain such a nitrogen concentration can be easily determined by calculation from the amount of polycrystalline raw material, the segregation coefficient of nitrogen, and the like.

  The initial interstitial oxygen concentration of the silicon single crystal rod is preferably 8 to 20 ppma. In order to set the initial interstitial oxygen concentration to the above desired value, a conventional method may be used. For example, by appropriately adjusting parameters such as the number of revolutions of the crucible, the flow rate of the introduced gas, the atmospheric pressure, the temperature distribution and convection of the silicon melt, or the strength of the applied magnetic field, the amount of oxygen melted from the crucible and taken into the crystal The amount of oxygen produced can be adjusted.

  The resistivity of the silicon single crystal rod is preferably 10 Ω · cm or more. Such resistivity can be easily achieved by, for example, introducing a known resistivity adjusting dopant such as boron or phosphorus into a raw material polycrystal of a quartz crucible in advance.

Next, the head and tail of the silicon single crystal rod grown in this way are cut with a cutting device such as a wire saw, an inner peripheral blade slicer, or an outer peripheral blade slicer in accordance with a normal method, and silicon for inspection is measured from both ends of the straight cylinder portion. A single crystal substrate is cut out. At this time, if necessary, the silicon single crystal rod may be divided into two or more single crystal rods, and the inspection substrate may be cut out from both ends of each single crystal rod.
In this way, if the inspection substrate is cut out from both ends of the cylinder body and both are used for inspection, more accurate inspection is possible than when only the inspection substrate cut out from one end of the cylinder body is used for inspection. It becomes.

Next, the inspection substrate cut in this way is heat-treated at least at a temperature between 800 ° C. and the melting point of silicon (1420 ° C.), preferably between 900 ° C. and 1250 ° C., at least before the semiconductor element manufacturing process. By doing so, the donor action of nitrogen, oxygen, and nitrogen-oxygen mixture is eliminated. Such high-temperature heat treatment can erase not only NO donors but also oxygen and nitrogen donors. Such heat treatment can be performed using, for example, a resistance heating furnace or a rapid heating furnace, and is preferably performed for 10 seconds to 120 minutes.
The atmosphere for the heat treatment is preferably an atmosphere containing at least one of oxygen, nitrogen, hydrogen, and argon. At this time, the oxygen atmosphere may be dry or wet. Alternatively, oxygen and nitrogen, nitrogen and hydrogen, nitrogen and argon, hydrogen and argon, or an atmosphere in which three or more are mixed may be used.

Next, the resistivity of the inspection substrate that has been heat-treated in this way and has eliminated the donor action is measured. As a measuring method, for example, a known method such as a four-probe method can be used.
And the resistivity of the substrate measured in this way does not change greatly even if heat treatment is performed in a process of manufacturing a semiconductor element or the like. Accordingly, when the product substrate is cut out from the remaining portion of the straight cylindrical portion of the silicon single crystal rod after cutting out the test substrate, the measured resistivity of the test substrate is measured. If it is used as the guaranteed value, it is possible to guarantee the resistivity of the product substrate accurately.

  Next, an example of a method for producing a silicon single crystal substrate of the present invention will be specifically described. For the growth of a silicon single crystal rod, the cutting of the inspection substrate, the heat treatment performed by holding the inspection substrate at any temperature between 800 ° C. and the melting point of silicon, and the measurement of the resistivity of the inspection substrate, the resistivity It can be performed by the same method and procedure as the guarantee method.

  Next, the resistivity of the inspection substrate measured in this way is compared with the standard value of the resistivity of the product. When the resistivity of the inspection substrate is a value within such a predetermined standard range, the product silicon single crystal substrate is removed from the remaining portion of the cylindrical body of the silicon single crystal rod as described above. Cut using a cutting device. The product substrate thus cut is subjected to processes such as chamfering, lapping, etching, polishing, and washing as necessary. In this way, a product substrate in which the resistivity value is guaranteed to be within the standard range by the subsequent heat treatment can be manufactured.

  And at least prior to the semiconductor element manufacturing process, the product substrate is heat-treated by holding at any temperature between 800 ° C. and silicon melting point (1420 ° C.), preferably 900 ° C. to 1250 ° C., Similar to the inspection substrate, a product substrate having a resistivity within the standard range can be manufactured. As described above, this heat treatment can be performed using, for example, a resistance heating furnace or a rapid heating furnace, and is preferably performed for 10 seconds to 120 minutes. Further, the atmosphere during the heat treatment is preferably an atmosphere containing at least one of oxygen, nitrogen, hydrogen, and argon. At this time, the oxygen atmosphere may be dry or wet. Alternatively, oxygen and nitrogen, nitrogen and hydrogen, nitrogen and argon, hydrogen and argon, or an atmosphere in which three or more are mixed may be used.

  The silicon single crystal substrate manufactured by the above method is one in which the action as a donor of oxygen, nitrogen, and a nitrogen-oxygen mixture is sufficiently eliminated, and the resistivity of a semiconductor device manufactured using this as a substrate And high stability of threshold voltage, suitable for the production of high-quality semiconductor elements having the standard as set, and nitrogen doping, resulting in a high-quality silicon single crystal substrate with extremely few crystal defects on the substrate surface layer .

  Further, if the diameter of the silicon single crystal substrate is a large diameter of 150 mm or more, it is suitable for manufacturing the high-quality semiconductor element as described above with a high yield. Or it can be set as the large-diameter board | substrate beyond it.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.
(Example)
A silicon single crystal rod having a diameter of 200 mm, an oxygen concentration of 14 ppma (JEIDA), a nitrogen concentration of 5 × 10 ¹³ pieces / cm ³ and a resistivity of 20 Ω · cm (target standard value) was grown by the CZ method. Then, the silicon single crystal substrate for inspection is sliced and cut from both ends of the straight cylindrical portion of the single crystal rod, and the resistance as a donor of oxygen, nitrogen, and a nitrogen-oxygen mixture is erased at 900 ° C. in a resistance heating furnace. The heat processing which hold | maintains for 20 minutes at the temperature of was performed. Thereafter, the resistivity was measured and found to be 20.0 to 20.2 Ω · cm.

Since this value was within the range of the target standard value (20.0 ± 0.2 Ω · cm), 100 silicon single crystal substrates were sliced from the remaining portion of the straight cylindrical portion of the single crystal rod. Then, an annealing heat treatment was performed by holding at a temperature of 1200 ° C. for 1 hour in a resistance heating furnace to produce an annealed substrate.
When the resistivity of the 100 annealed substrates was measured, it was between 20.0 and 20.2 Ω · cm.

(Comparative example)
Similarly to the example, a silicon single crystal rod having a diameter of 200 mm, an oxygen concentration of 14 ppma (JEIDA), a nitrogen concentration of 5 × 10 ¹³ pieces / cm ³ and a resistivity of 20 Ω · cm (target standard value) was grown by the CZ method. Then, the silicon single crystal substrate for inspection is sliced and cut from both ends of the straight cylindrical portion of the single crystal rod, and is held at a temperature of 650 ° C. for 20 minutes in order to eliminate the action of oxygen as a donor. A heat treatment was performed. Thereafter, the resistivity was measured and found to be 20.6 to 20.8 Ω · cm.

Next, 100 silicon single crystal substrates were sliced from the remaining portion of the straight cylindrical portion of the single crystal rod and annealed by holding at a temperature of 1200 ° C. for 1 hour in a resistance heating furnace to prepare an annealed substrate. .
When the resistivity of these 100 annealed substrates was measured, it was between 20.0 and 20.2 Ω · cm, which was lower by about 0.6 Ω · cm than the resistivity of the inspection substrate.

  The present invention is not limited to the above embodiment. The above embodiment is merely an example, and the present invention has the same configuration as that of the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

  For example, in the above embodiment, the case where the standard value of resistivity of the silicon single crystal substrate is 20 Ω · cm is exemplified, but the effect of the present invention can be obtained if the resistivity is 10 Ω · cm or more. Further, the diameter of the silicon single crystal substrate is not limited to 200 mm, and may be 300 mm or more.

It is a graph which shows the effect (NO ((rho) 2- (rho) 1)) of the heat processing temperature for NO donor elimination, and the resistivity before and behind heat processing, ie, the effect of NO donor elimination. Substrate (B) subjected to heat treatment for oxygen donor erasure, and substrate (C) subjected to heat treatment at 1200 ° C. for 1 hour for NO donor erasure, and oxygen donor erasure without adding nitrogen for comparison. It is a FT-IR spectrum of the board | substrate (A) which heat-processed this.

Claims (17)

  A method for guaranteeing resistivity of a silicon single crystal substrate, and at least when growing a silicon single crystal rod by the Czochralski method, nitrogen is added to the silicon single crystal rod, and the grown silicon single crystal rod The silicon single crystal substrate for inspection is cut from both ends of the cylindrical body of the cylinder, and the cut silicon single crystal substrate for inspection is cut at a temperature between 800 ° C. and the melting point of silicon at least before the semiconductor element manufacturing process. Holding and heat-treating, measuring the resistivity of the heat-treated inspection silicon single crystal substrate, and measuring the measured resistivity value of the inspection silicon single-crystal substrate, the remaining cylindrical body portion of the silicon single-crystal rod A method for guaranteeing the resistivity of a silicon single crystal substrate, characterized by being used as a guarantee value of the resistivity of a silicon single crystal substrate for a product that is cut from the portion.   2. The silicon single crystal substrate resistivity guarantee method according to claim 1, wherein an initial interstitial oxygen concentration of the grown silicon single crystal rod is 8 to 20 ppma. ^3. The resistivity guarantee of a silicon single crystal substrate according to claim 1 or 2, wherein a nitrogen concentration of the silicon single crystal rod to be grown is 1 × 10 ^{13 to} 5 × 10 ¹⁵ pieces / cm ^3. Method.   The resistivity guarantee method for a silicon single crystal substrate according to any one of claims 1 to 3, wherein a resistivity of the silicon single crystal rod to be grown is 10 Ω · cm or more.   The atmosphere of the heat treatment performed on the silicon single crystal substrate for inspection is an atmosphere containing at least one of oxygen, nitrogen, hydrogen, and argon. A method for guaranteeing resistivity of the described silicon single crystal substrate.   6. The resistance of a silicon single crystal substrate according to claim 1, wherein the heat treatment performed on the silicon single crystal substrate for inspection is performed using a resistance heating furnace or a rapid heating furnace. Rate guarantee method.   The method for guaranteeing resistivity of a silicon single crystal substrate according to any one of claims 1 to 6, wherein the heat treatment performed on the silicon single crystal substrate for inspection is performed for 10 seconds to 120 minutes.   A method of manufacturing a silicon single crystal substrate, wherein at least when growing a silicon single crystal rod by the Czochralski method, nitrogen is added to the silicon single crystal rod, and the straight body of the grown silicon single crystal rod A silicon single crystal substrate for inspection is cut from both ends of the cylindrical portion, the cut silicon single crystal substrate for inspection is heat-treated while being held at any temperature between 800 ° C. and the melting point of silicon, and the heat-treated inspection is performed. The resistivity of the silicon single crystal substrate is measured, and when the measured resistivity value of the silicon single crystal substrate for inspection is a value within a predetermined standard range, the remaining cylinder portion of the straight cylinder portion of the silicon single crystal rod is measured. A method for producing a silicon single crystal substrate, comprising: cutting a product silicon single crystal substrate from a portion.   9. The silicon according to claim 8, wherein the cut silicon single crystal substrate for product is heat-treated at least at a temperature between 800 ° C. and a melting point of silicon at least before the semiconductor element manufacturing process. A method for manufacturing a single crystal substrate.   The method for producing a silicon single crystal substrate according to claim 8 or 9, wherein an initial interstitial oxygen concentration of the silicon single crystal rod to be grown is 8 to 20 ppma. 11. The silicon single crystal according to claim 8, wherein the silicon single crystal rod to be grown has a nitrogen concentration of 1 × 10 ^{13 to} 5 × 10 ¹⁵ pieces / cm ^3. A method for manufacturing a substrate.   The method for manufacturing a silicon single crystal substrate according to any one of claims 8 to 11, wherein a resistivity of the silicon single crystal rod to be grown is set to 10 Ω · cm or more.   13. The heat treatment atmosphere performed on the inspection or product silicon single crystal substrate is an atmosphere containing at least one of oxygen, nitrogen, hydrogen, and argon. 2. A method for producing a silicon single crystal substrate according to item 1.   The silicon single crystal according to any one of claims 8 to 13, wherein the heat treatment performed on the silicon single crystal substrate for inspection or product is performed using a resistance heating furnace or a rapid heating furnace. A method for manufacturing a substrate.   The method for producing a silicon single crystal substrate according to any one of claims 8 to 14, wherein the heat treatment performed on the silicon single crystal substrate for inspection or product is performed for 10 seconds to 120 minutes.   A silicon single crystal substrate manufactured by the method according to any one of claims 8 to 15.   The silicon single crystal substrate according to claim 16, wherein a diameter of the silicon single crystal substrate is 150 mm or more.

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