JP4978544B2 - Epitaxial wafer manufacturing method - Google Patents

Description

  The present invention relates to an epitaxial wafer manufacturing method in which an epitaxial layer is formed on an ion-implanted substrate.

  As a silicon single crystal substrate for forming a semiconductor element, a silicon single crystal substrate grown by a CZ (Czochralski) method or an MCZ (Magnetic field CZ) method, or an epitaxial layer is formed on the surface of these silicon single crystal substrates. Conventionally, an epitaxial wafer, an annealed wafer obtained by subjecting a silicon single crystal substrate to heat treatment, and the like have been used.

  On the other hand, semiconductor devices are manufactured in an ultra clean room of class 100 or less, but completely avoid contamination of the silicon single crystal substrate by impurities from raw materials (gas, water, chemicals) and semiconductor manufacturing equipment. I can't. If these impurities are present in the element active region of the silicon single crystal substrate, the quality and characteristics of the semiconductor element are significantly deteriorated. Therefore, intrinsic gettering (IG) and extrinsic gettering (EG) are conventionally performed in order to getter these impurities and remove them from the element active region. Furthermore, an epitaxial layer may be formed on the surface of the substrate subjected to these treatments.

  In particular, from the viewpoint of manufacturing a semiconductor element, an epitaxial wafer can form an electrically active layer having a resistivity different from that of a substrate. Since there are many advantages such as the ability to form a single crystal thin film of high purity with a low concentration of oxygen or carbon that causes defects to an arbitrary thickness, a high voltage semiconductor device, an integrated circuit device, a solid-state imaging device (CCD <Charge− (Coupled Device>, CIS <CMOS Image Sensor>) and the like.

As a general method for forming an epitaxial layer, for example, a CVD method (Chemical Vapor Deposition method) is used, and the following four main source gases are used. In the hydrogen reduction method, SiCl ₄ and SiHCl ₃ are used as source gases, and in the thermal decomposition method, SiH ₂ Cl ₂ and SiH ₄ are used as source gases.

  However, in an epitaxial wafer in which an epitaxial layer is formed using any source gas, many impurities, particularly metal impurities, are mixed during the formation of the epitaxial layer. When such metal impurities are applied to a solid-state imaging device, white scratch defects due to dark current cannot be sufficiently reduced, causing deterioration in characteristics and yield.

As a generation source of heavy metal impurities, a source from a SUS member in an epitaxial growth apparatus or a source gas pipe can be considered. If the source gas contains chlorine, it is decomposed during epitaxial growth to produce HCl gas. It is considered that the HCl gas corrodes the SUS-based member in the bell jar and is taken into the source gas as a metal chloride, and this metal chloride is taken into the epitaxial layer.
In addition, HCl gas may be intentionally introduced to lightly etch off the surface of the silicon single crystal substrate before forming the epitaxial layer, which also contributes to corrosion.

  Therefore, when a solid-state imaging device is formed using an epitaxial wafer, carbon ions are implanted from one surface of a silicon wafer as a gettering technique for gettering and removing the metal impurities, and a carbon ion implantation region is obtained. There is a method of manufacturing a carbon gettering epitaxial wafer in which a silicon epitaxial layer is formed on this surface.

  For example, Patent Document 1 discloses a semiconductor substrate manufacturing method in which ions are implanted from the surface side of a semiconductor substrate to form a gettering site inside the semiconductor substrate. According to claim 1 of Patent Document 1, an ion containing at least a second element (for example, carbon) different from the first element constituting the semiconductor substrate and belonging to the first element is included in the semiconductor substrate. And an epitaxial layer is formed on the surface of the ion-implanted substrate.

  Further, in claim 3 of Patent Document 1, an oxide film is formed on the surface of the semiconductor substrate, and ions containing at least the second element are implanted into the semiconductor substrate through the oxide film. A method for removing the oxide film is described. Thus, by forming an oxide film on the surface of the semiconductor substrate, sputtering of the surface of the semiconductor substrate (scattering of metal particles) due to ion implantation of the second element is prevented, and a semiconductor substrate having a high-quality epitaxial layer is manufactured. It is supposed to be possible.

  Also, for example, in Patent Document 2, in a method for manufacturing a semiconductor substrate in which ion implantation is performed from the surface side of the semiconductor substrate to form a uniform and high-density gettering site at a predetermined depth of the semiconductor substrate, In order to improve controllability in the depth direction, ions are implanted from the mirror surface of the substrate without oxide film, etc., and impurities on the substrate surface side are removed by low-temperature heat treatment in an oxidizing gas atmosphere before epitaxial growth after this ion implantation. A method of forming a defect-free layer on the substrate surface side by high-temperature heat treatment in a non-oxidizing gas atmosphere and forming a high-density gettering site and removing the thermal oxide film formed by heat treatment after the heat treatment has been proposed. .

  However, even these manufacturing methods are not sufficient for reducing defects generated in the epitaxial layer, and it is difficult to manufacture a high-quality epitaxial wafer.

Japanese Patent No. 3384506 JP 2007-173328 A

  Therefore, the present invention has been made in view of the above problems, and provides an epitaxial wafer manufacturing method capable of forming a high-quality epitaxial layer on a substrate on which a high-density gettering site is formed. With the goal.

In order to achieve the above object, the present invention provides a method for manufacturing an epitaxial wafer, comprising at least a step of forming an organic film having a uniform thickness on the surface of a silicon single crystal substrate, and ion implantation through the organic film. A step of forming an ion implantation layer on the silicon single crystal substrate, a step of removing the organic film, and a step of forming an epitaxial layer on the surface from which the organic film has been removed. An epitaxial wafer manufacturing method is provided.

  In this way, by ion implantation through the organic film, it is possible to prevent channeling of implanted ions and to prevent sputtering and particle adhesion to the surface of the silicon single crystal substrate during ion implantation, thus protecting the substrate surface. An ion implantation layer can be formed. Furthermore, since the organic film is used as a protective film on the substrate surface, high-temperature heat treatment is not required for the formation and removal of the organic film, so that there are almost no defects on the substrate surface due to oxygen precipitation.

Thereby, since an epitaxial layer can be formed on the substrate surface with few defects, the defect which arises at the time of epitaxial growth can be prevented effectively, and a good-quality epitaxial layer can be formed.
By being manufactured in this way, the ion implantation layer is formed in the vicinity of the substrate surface as a high-density gettering site, and the impurity contamination of the epitaxial layer formed on the surface is reduced. For this reason, the epitaxial wafer manufactured by the manufacturing method of the present invention has an epitaxial layer that is almost free from impurity contamination and defects, and thus is suitable for use in manufacturing a solid-state imaging device, for example.

At this time, it is preferable that the step of forming the organic film is performed by baking or UV curing after the organic film is applied.
In this way, by performing low temperature baking or UV curing after applying the organic film, excess solvent in the organic film is volatilized and the organic film is cured, so that peeling in a later step can be prevented. . In addition, since the organic film is heated by the collision energy of ions during ion implantation, it is possible to prevent excess solvent in the organic film from being volatilized and releasing gas, thereby deteriorating the degree of vacuum in the apparatus. An injection can be performed.

At this time, before the step of forming the epitaxial layer, the silicon single crystal substrate from which the organic film has been removed can be annealed at 500 ° C. or more and 120 seconds or less.
As described above, by annealing at 500 ° C. or higher before forming the epitaxial layer, it is possible to recover the implantation damage on the surface of the substrate due to ion implantation. Oxygen precipitates can be prevented from being generated on the surface due to oxygen aggregation. In addition, according to the manufacturing method of the present invention, since defects on the substrate surface that occur during ion implantation are reduced, desired damage recovery can be performed even with short-time annealing.

At this time, the step of forming the ion implantation layer is performed by ion-implanting carbon ions or carbon-containing ions at a dose of 5 × 10 ^{13 to} 5 × 10 ¹⁵ / cm ^{2 to} the silicon single crystal substrate. It is preferable to form an injection layer (claim 4).
Thus, a wafer with higher gettering capability can be obtained by ion-implanting carbon ions or ions containing carbon at a dose in the above range.

At this time, the organic film can be a photoresist film.
Thus, in the manufacturing method of the present invention, the organic film to be formed can be a photoresist film generally used as an organic film.

At this time, the step of removing the organic film can be performed by any one of ashing, sulfuric acid / hydrogen peroxide treatment, organic solvent treatment, or a combination of these treatments (Claim 6).
As described above, the organic film can be removed by any treatment, and when it is difficult to remove the organic film by curing the organic film, the organic film can be removed by combining these treatments.

Moreover, that provides a solid-state imaging device characterized in that it is manufactured using an epitaxial wafer manufactured by the manufacturing method of the epitaxial wafer of the present invention.
Thus, an epitaxial wafer manufactured by the method for manufacturing an epitaxial wafer of the present invention has an epitaxial layer with few defects, and a high-density gettering site is formed in the vicinity thereof. Impurity contamination is also reduced, and by manufacturing a solid-state imaging device using this wafer, a high-quality solid-state imaging device with few characteristic defects can be obtained.

  As described above, according to the epitaxial wafer manufacturing method of the present invention, the organic film formed on the substrate surface prevents channeling of implanted ions and prevents sputtering of the substrate surface and adhesion of particles during ion implantation. Therefore, the defect which arises in an epitaxial layer can be effectively reduced by forming an epitaxial layer on the favorable substrate surface which removed the organic film after that. In addition, since the high-temperature heat treatment necessary for forming the thermal oxide film is not necessary for forming the organic film, oxygen precipitate defects are not generated on the wafer surface before epitaxial growth. Therefore, no defects are generated in the epitaxial layer grown thereafter. In addition, since a high-density gettering site is formed in the vicinity of the epitaxial layer, a high-quality epitaxial wafer with reduced impurity contamination can be manufactured.

When an epitaxial wafer is manufactured by ion implantation to form an epitaxial layer on the surface, defects and the like are generated on the substrate surface during ion implantation. Therefore, when an epitaxial layer is formed on the surface, many defects are generated during growth. There was a problem.
The present inventors examined such a problem as follows.

In order to solve the above problems, Patent Document 1 discloses a method of forming an epitaxial layer by ion implantation through an oxide film and then removing the oxide film.
However, the oxide film forming method is generally performed by exposing the substrate to a high temperature and oxidizing atmosphere as described in the example of Patent Document 1. In the above embodiment, the dry oxidation is performed at 1000 ° C. for 10 minutes. When the substrate is treated at a relatively high temperature in this way, oxygen in the crystal is precipitated and oxygen precipitates are formed. Although this oxygen precipitate is usually formed in the bulk, the surface of the substrate is hard to be formed on the surface and is defect-free because oxygen is diffused outward during the heat treatment.

  However, it has been found that depending on the combination of crystal oxygen concentration, heat treatment conditions, and the like, surface oxygen is not sufficiently diffused outward and very fine oxygen precipitates may be formed on the surface side. Although this minute oxygen precipitate is extremely minute after the heat treatment, it is difficult to observe with the current technology. However, when an epitaxial layer is grown on such a substrate, stacking faults with this minute oxygen precipitate as a nucleus are generated. Is generated in the epitaxial layer. This stacking fault causes poor device characteristics.

Such a problem is the same in Patent Document 2 in which heat treatment is performed after ion implantation.
Further, in Patent Document 2, ion implantation is performed with the surface of the semiconductor substrate exposed. Ion implantation in such a state causes crystallinity degradation due to sputtering of the substrate surface and channeling of implanted ions. Furthermore, the substrate surface cannot be sufficiently protected from contaminants such as particles flying during ion implantation.

  As a result of diligent studies on the problems such as these, the present inventors have formed an organic film on the surface of the substrate to perform ion implantation, thereby preventing channeling of implanted ions and the surface of the substrate during ion implantation. This eliminates the need for high-temperature heat treatment for forming an oxide film and heat treatment for reducing defects on the substrate surface after ion implantation, thereby preventing generation of defects on the substrate surface due to oxygen precipitation. Has found that a high-quality epitaxial layer can be formed, and has completed the present invention.

Hereinafter, although the manufacturing method of the epitaxial wafer of this invention is demonstrated in detail, referring to FIG. 1 as an example of an embodiment, this invention is not limited to this.
FIG. 1 is a flow chart as an example of an embodiment of an epitaxial wafer manufacturing method of the present invention.

As shown in FIG. 1A, in the manufacturing method of the present invention, an organic film 11 is first formed on the surface of a silicon single crystal substrate 10.
As the silicon single crystal substrate 10 prepared at this time, for example, a silicon single crystal rod is grown by the Czochralski method, and the grown silicon single crystal rod is sliced by a cutting device such as an inner peripheral slicer or a wire saw, A silicon single crystal substrate manufactured through processes such as chamfering, lapping, etching, and polishing is prepared.

A method for forming the organic film 11 is not particularly limited. For example, a spin coating method in which a material of the organic film is discharged onto the substrate and the substrate is rotated to form the organic film uniformly is used. An organic film having a thickness of about 4 μm can be formed.
As described above, since the protective film on the substrate surface is an organic film in the manufacturing method of the present invention, a high-temperature heat treatment for formation and removal is unnecessary, and defects due to oxygen precipitates are almost always generated on the substrate surface. In addition, defects in the epitaxial layer formed thereafter can be reduced.

  Although it can select suitably as an organic film, the photoresist film generally used can be formed, for example, a positive type photoresist film can be formed. If it is a photoresist film | membrane, it is what is normally used with respect to a semiconductor wafer, and it is suitable also from the viewpoint of the formation technology of a film | membrane, and impurity generation prevention.

Moreover, in the manufacturing method of this invention, it is preferable to perform low temperature baking or UV curing after apply | coating an organic film as the process of forming the organic film 11. FIG.
Thus, peeling or the like in the step after the organic film is cured can be prevented by performing baking or UV curing after applying the organic film. Furthermore, since it is possible to prevent the excess solvent from being volatilized by heating the organic film due to the collision energy of ions during ion implantation, it is possible to perform good ion implantation in a device having a higher degree of vacuum.

Next, as shown in FIG. 1B, in the manufacturing method of the present invention, an ion implantation layer 12 is formed on the silicon single crystal substrate 10 by ion implantation through the organic film 11.
In this way, ion implantation through the organic film can prevent channeling of implanted ions, and since the substrate surface is protected during ion implantation, sputtering and particle adhesion to the substrate surface are effective. Can be prevented.

The ion to be implanted and the dose thereof are not particularly limited, but carbon ions or ions containing carbon are ion-implanted at a dose of 5 × 10 ^{13 to} 5 × 10 ¹⁵ / cm ^2. It is preferable to form the ion implantation layer 12 on the crystal substrate 10.
In this way, carbon ions or carbon-containing ions are ion-implanted at a dose in the above range, so that the formed ion implantation layer becomes a gettering site with higher gettering capability, and an epitaxial layer formed thereon Impurity contamination can be effectively reduced.

Next, as shown in FIG. 1C, in the manufacturing method of the present invention, the organic film 11 is removed.
As a method for removing the organic film 11, the organic film can be removed by any one of ashing, sulfuric acid / hydrogen peroxide treatment, organic solvent treatment, or a combination of these treatments. With these treatments, the organic film can be easily removed, and organic films that are hard to be removed by curing at a temperature during baking or ion implantation can be removed by using these treatments in combination.

For example, in ashing (ashing treatment), a substrate is inserted into an ashing device, and oxygen is plasma-decomposed to generate active oxygen atoms and ozone in the device, whereby the organic film is peeled and removed.
Further, after the organic film is removed, in order to further clean the substrate surface, for example, by washing with an SC1 solution or a hydrofluoric acid aqueous solution, a higher quality epitaxial layer can be formed in a later step.

Next, as shown in FIG. 1D, in the manufacturing method of the present invention, an epitaxial layer 13 is formed on the surface from which the organic film 11 has been removed.
General conditions can be used to form the epitaxial layer 13. For example, an epitaxial layer may be formed by introducing a source gas such as SiHCl ₃ into the chamber using H ₂ as a carrier gas and epitaxially growing it at about 1050 to 1250 ° C. on a substrate placed on the susceptor by CVD. it can.

  As described above, since the substrate surface has few defects even after the ion implantation is performed by the manufacturing method of the present invention, defects at the time of forming the epitaxial layer hardly occur by forming the epitaxial layer thereon.

Further, before the step of forming the epitaxial layer 13, the silicon single crystal substrate 10 from which the organic film 11 has been removed can be annealed at 500 ° C. or more and 120 seconds or less.
In this way, by annealing at 500 ° C. or higher, damage to the substrate surface due to ion implantation can be recovered. According to the manufacturing method of the present invention, the substrate surface is protected by an organic film during ion implantation. Therefore, defects on the substrate surface and the like are significantly reduced compared to conventional ion implantation, and even when annealing is performed for a short time so that oxygen does not precipitate on the substrate surface for 120 seconds or less, the substrate surface is very good. be able to. Thereby, an epitaxial layer with fewer defects can be formed on the substrate.

  The epitaxial wafer manufactured in this way has a high-density gettering site in the vicinity of the epitaxial layer with reduced defects, so that there is little impurity contamination in the epitaxial layer. By manufacturing a solid-state imaging device, a solid-state imaging device having excellent quality with few characteristic defects can be obtained.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited to this.

(Example)
Hereinafter, an embodiment will be described with reference to FIG.
First, a substrate having a plane orientation (100), a resistivity of 10 to ²⁰ ohm · cm, and an oxygen concentration of 1.12 × 10 ¹⁸ atoms / cm ³ grown by the Czochralski method (CZ method) as the silicon single crystal substrate 10. The substrate was washed with an NH ₄ OH / H ₂ O ₂ aqueous solution and an HCl / H ₂ O ₂ aqueous solution.

Next, an organic thin film 11 was formed on the substrate 10 as shown in FIG.
First, a positive photoresist having a viscosity of 5 CP was discharged onto the substrate, the substrate was rotated at 6000 rpm, and the positive photoresist was applied onto the substrate by a so-called spin coating method. Thereafter, the substrate was baked on a hot plate at 110 ° C. for 90 seconds to volatilize excess solvent components, and at the same time, the spin-coated positive photoresist was cured. In this way, a photoresist film having a thickness of 0.4 μm was formed.

Next, as shown in FIG. 1B, carbon was ion-implanted from the surface with an energy of 140 KeV and a dose of 1 × 10 ¹⁵ / cm ² through the photoresist film 11 to form an ion-implanted layer 12.
The projected range of carbon at this time was approximately 0.23 μm from the photoresist film / silicon single crystal substrate interface, and the peak concentration was approximately 5 × 10 ¹⁹ atoms / cm ³ .

Next, as shown in FIG. 1 (c), removing the photoresist film 11 which becomes unnecessary in _{H 2 SO 4 / H 2 O} 2 aqueous solution (SPM process). Since it was a photoresist film cured by heat at the time of baking or ion implantation, it was difficult to remove with an aqueous solution of H ₂ SO ₄ / H ₂ O _2. It was removed by ashing (ashing treatment). Thereafter, in order to remove the natural oxide film on the surface formed during the H ₂ SO ₄ / H ₂ O ₂ treatment (sulfuric acid / hydrogen peroxide treatment) with an HF aqueous solution and further improve the cleanliness of the substrate surface, NH ₄ Washed with aqueous OH / H ₂ O _{2 and} aqueous HCl / H ₂ O ₂ .

Next, as shown in FIG. 1D, the epitaxial layer 13 was formed. First, recovery annealing for ion implantation damage was performed, and epitaxial growth was continuously performed in the same chamber. Specifically, after the substrate is placed in the chamber, annealing is performed at 1200 ° C. for 60 seconds in a hydrogen atmosphere, and then SiHCl ₃ gas is continuously introduced in the same chamber, the thickness is 7 μm, and the resistivity is 10 ohm · cm. An epitaxial layer was grown.

  It goes without saying that continuous processing in this way is advantageous for shortening the process time and reducing costs, but of course, annealing and epitaxial growth may be performed separately. As for the annealing temperature, 500 ° C. or more is sufficient from the viewpoint of recovery of ion implantation damage. However, if annealing is performed at a high temperature in a hydrogen atmosphere, a small amount of natural oxide film remaining on the surface. Can be removed by hydrogen reduction, whereby a higher quality epitaxial layer can be obtained. Furthermore, if the annealing time is set to 120 seconds or less, there is no sufficient time for oxygen to aggregate, and the generation of minute oxygen precipitates is suppressed, so that the generation of stacking faults during the subsequent epitaxial layer growth can be prevented.

FIG. 2 shows the results of evaluating the surface defects of the epitaxial wafer manufactured in this way with a surface inspection apparatus using laser scattering.
As can be seen from FIG. 2, according to the manufacturing method of the present invention, it can be seen that a good epitaxial layer having almost no defects can be formed.

(Comparative Example 1)
Hereinafter, Comparative Example 1 will be described with reference to FIG.
Comparative Example 1 is a case where a thermal oxide film is formed while an organic film (photoresist film) is formed before ion implantation in the example.
First, the same silicon single crystal substrate 15 as in Example 1 was prepared, and washed with an HF aqueous solution, an NH ₄ OH / H ₂ O ₂ aqueous solution, and an HCl / H ₂ O ₂ aqueous solution.

  Next, as shown in FIG. 3A, an oxide film 14 having a thickness of 24 μm was formed on the surface of the substrate 15 by thermal oxidation. This oxide film acts as an anti-sputtering, channeling and anti-fouling substance on the substrate surface.

Next, as shown in FIG. 3B, carbon was ion-implanted from the surface through the oxide film 14 with an energy of 70 KeV and a dose of 1 × 10 ¹⁵ / cm ² to form an ion-implanted layer 16. The projected range of carbon at this time was approximately 0.2 μm from the oxide film / silicon single crystal substrate interface, and the peak concentration was approximately 4 × 10 ¹⁹ atoms / cm ³ .
Next, as shown in FIG. 3C, in order to remove the unnecessary oxide film 14 with an HF aqueous solution and further increase the cleanliness of the substrate surface, an NH ₄ OH / H ₂ O ₂ aqueous solution, and Washed with aqueous HCl / H ₂ O ₂ solution.

Next, as shown in FIG. 3D, the epitaxial layer 17 was formed. First, recovery annealing for ion implantation damage was performed, and epitaxial growth was continuously performed in the same chamber. Specifically, after the substrate is placed in the chamber, annealing is performed at 1200 ° C. for 60 seconds in a hydrogen atmosphere, and then SiHCl ₃ gas is continuously introduced in the same chamber, the thickness is 7 μm, and the resistivity is 10 ohm · cm. An epitaxial layer was grown.

FIG. 2 shows the results of evaluating the surface defects of the epitaxial wafer manufactured in this way with a surface inspection apparatus using laser scattering.
As can be seen from FIG. 2, in Comparative Example 1, it can be seen that a large number of surface defects are generated. As described above, it is considered that the cause is that when the semiconductor substrate is subjected to an oxidation heat treatment, a minute oxygen precipitate is deposited on the surface, and an epitaxial stacking fault is generated with this as a nucleus.

(Comparative Example 2)
Hereinafter, Comparative Example 2 will be described with reference to FIG.
In Comparative Example 2, an organic film (photoresist film) is formed before ion implantation in the example, whereas carbon ions are directly implanted into the substrate surface without forming a protective film or the like.
First, as shown in FIG. 4A, a silicon single crystal substrate 15 similar to that in Example 1 is prepared and washed with an HF aqueous solution, an NH ₄ OH / H ₂ O ₂ aqueous solution, and an HCl / H ₂ O ₂ aqueous solution. did.

Next, as shown in FIG. 4B, carbon was ion-implanted from the surface of the substrate 15 with an energy of 70 KeV and a dose amount of 1 × 10 ¹⁵ / cm ² to form an ion-implanted layer 16. The projected range of carbon at this time was approximately 0.2 μm from the oxide film / silicon single crystal substrate interface, and the peak concentration was approximately 4 × 10 ¹⁹ atoms / cm ³ .
However, there were variations in the thickness and depth of the ion implantation layer 16 that was thought to be based on channeling.

Next, as shown in FIG. 4C, the epitaxial layer 17 was formed. First, recovery annealing for ion implantation damage was performed, and epitaxial growth was continuously performed in the same chamber. Specifically, after the substrate is placed in the chamber, annealing is performed at 1200 ° C. for 60 seconds in a hydrogen atmosphere, and then SiHCl ₃ gas is continuously introduced in the same chamber, the thickness is 7 μm, and the resistivity is 10 ohm · cm. An epitaxial layer was grown.

FIG. 2 shows the results of evaluating the surface defects of the epitaxial wafer manufactured in this way with a surface inspection apparatus using laser scattering.
As can be seen from FIG. 2, in Comparative Example 2, since there is no heat treatment that forms fine oxygen precipitates before epitaxial growth, many surface defects as shown in Comparative Example 1 are not observed. However, several tens of defects that are thought to be caused by particles adhered during ion implantation have been observed. This is presumably because the cleanliness of the substrate surface before epitaxial growth was not sufficient because ion implantation was performed without a protective film.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as 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.

It is a flowchart which shows an example of the process of the manufacturing method of the epitaxial wafer of this invention. It is the graph which evaluated the number of defects of the surface of an epitaxial layer with a surface inspection device. FIG. 6 is a flowchart showing steps of a method for manufacturing an epitaxial wafer of Comparative Example 1. 10 is a flowchart showing a process of an epitaxial wafer manufacturing method of Comparative Example 2. FIG.

Explanation of symbols

10, 15 ... silicon single crystal substrate, 11 ... organic film, 12, 16 ... ion implantation layer,
13, 17 ... epitaxial layer, 14 ... oxide film.

Claims (6)

A method for producing an epitaxial wafer, comprising at least a step of forming an organic film having a uniform thickness on a surface of a silicon single crystal substrate, and an ion implantation layer formed on the silicon single crystal substrate by ion implantation through the organic film. An epitaxial wafer manufacturing method comprising: a forming step; a step of removing the organic film; and a step of forming an epitaxial layer on the surface from which the organic film has been removed.   The method for producing an epitaxial wafer according to claim 1, wherein the step of forming the organic film is performed by baking or UV curing after the organic film is applied.   3. The epitaxial wafer according to claim 1, wherein the silicon single crystal substrate from which the organic film has been removed is annealed at a temperature of 500 ° C. or more and 120 seconds or less before the step of forming the epitaxial layer. Manufacturing method. The step of forming the ion implantation layer is performed by implanting carbon ions or carbon-containing ions at a dose of 5 × 10 ^{13 to} 5 × 10 ¹⁵ / cm ² to form the ion implantation layer on the silicon single crystal substrate. It forms, The manufacturing method of the epitaxial wafer as described in any one of Claim 1 thru | or 3 characterized by the above-mentioned.   The method for manufacturing an epitaxial wafer according to any one of claims 1 to 4, wherein the organic film is a photoresist film.   6. The method according to claim 1, wherein the step of removing the organic film includes removing the organic film by ashing, sulfuric acid / hydrogen peroxide treatment, organic solvent treatment, or a combination of these treatments. An epitaxial wafer manufacturing method according to claim 1.

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