JP2013157629A - Method of manufacturing bonded soi wafer, and bonded soi wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a bonded SOI wafer in which a gettering site is formed at an interface between an SOI layer and an insulator layer (oxide film), and to provide an SOI wafer.SOLUTION: In a method of manufacturing a bonded SOI wafer, bonding is performed in such a condition as an organic substance is attached on a wafer surface before the bonding, and a bond strengthening thermal treatment is performed in a condition in which the organic substance is enclosed at the bonding interface, thereby generating crystal defect at the bonding interface. As a specific method for achieving it, the following methods can be applied: a method of cleaning the wafer surface in an atmosphere containing organic substance; a method of drying the wafer surface in an atmosphere containing the organic substance; a method of processing the wafer surface using cleaning liquid containing the organic substance; a method of applying or dropping a processing liquid containing the organic substance on the wafer surface; or the like. The bonded SOI wafer contains minute crystal defects comprised of SiC and having gettering capability at the bonding interface, thereby capable of effectively removing heavy metal impurity that degrades device characteristics.

Description

  The present invention relates to a method for manufacturing a bonded SOI wafer having a gettering layer for removing heavy metal impurities caused by processes that adversely affect device operation, and a bonded SOI wafer.

  As semiconductor devices are miniaturized and highly integrated, the influence of wafer contamination on device characteristics is increasing. Conventionally, gettering technology has been used as a method for removing contamination caused by processes introduced in wafer processing and device manufacturing processes, particularly heavy metal impurities from the active region of an integrated circuit.

  As gettering technology, polycrystalline silicon is deposited on the back surface of a semiconductor substrate by a low pressure CVD method, and this is used as a gettering source, a method using heavy metal impurity trapping ability due to crystal defects such as oxygen precipitates or dislocations, etc. Is well known.

  There are many examples of applying gettering in a conventional semiconductor substrate to an SOI (Silicon On Insulator) wafer in which an SOI layer is formed on an insulator, but in an SOI wafer, an oxidation that exists between the SOI layer and the supporting Si substrate. An insulator layer such as a film inhibits the movement of heavy metal impurities, and a sufficient gettering effect cannot be obtained.

  Therefore, in order to effectively add a gettering source, a gettering source is formed at the interface between the SOI layer and the insulator layer (oxide film), and the added gettering source has an adverse effect on the device region. It is necessary to have a structure that does not extend. However, since the manufacturing process of SOI wafers is more complicated than that of normal wafers, the manufacturing cost is high, and if the number of processes for adding a gettering source is increased, the manufacturing cost of SOI wafers is further increased.

  For example, in Patent Document 1, carbon ions are implanted into an oxide film on a supporting substrate (supporting wafer), an SOI layer substrate is bonded to the surface of the oxide film, and then heat treatment is performed, whereby the oxide film and A method for manufacturing an SOI wafer is disclosed in which oxygen is deposited using carbon as a nucleus at the interface of an SOI layer substrate. However, this method also requires a process of implanting carbon ions into the oxide film on the support substrate and a heat treatment process for forming and growing precipitation nuclei after bonding, and an increase in manufacturing cost is inevitable. .

Japanese Patent No. 3217089

  The present invention has been made in view of such circumstances, and a simple and inexpensive gettering source is formed at the interface between the SOI layer and the insulator layer (oxide film), thereby deteriorating device characteristics and oxide film breakdown voltage characteristics. An object of the present invention is to provide a bonded SOI wafer manufacturing method and a bonded SOI wafer having a function of effectively removing heavy metal impurities.

  In order to achieve the above object, the present inventors have repeatedly studied a method of adding a gettering source on a conventional SOI wafer manufacturing process without increasing the number of processes. As a result, it was found that by bonding with the organic substance adsorbed on the wafer surface before bonding, a fine crystal defect having a gettering action can be formed at the bonding interface in the subsequent bonding strengthening heat treatment. .

  The present invention has been made on the basis of the above findings, and the gist of the present invention is the following (1) bonded SOI wafer manufacturing method and (2) bonded SOI wafer.

  (1) A bonded SOI in which an SOI layer is formed on a buried oxide film by bonding an active layer wafer to be an SOI layer and a support wafer through an oxide film and then thinning the active layer wafer. In the method of manufacturing a wafer, bonding is performed in a state where organic substances are adsorbed on the wafer surface before bonding, and a crystal defect is formed at the bonding interface by performing a bonding strengthening heat treatment in a state where the organic substances are confined to the bonding interface. A method for manufacturing a bonded SOI wafer.

  The above-mentioned “crystal defects” are minute crystal defects caused by carbon (C) produced by decomposition of organic substances by bonding with the organic substance adsorbed on the wafer surface and performing a joint strengthening heat treatment. The presence of carbon at the bonding interface where crystal defects are formed can be confirmed by secondary ion mass spectrometry (SIMS), and the presence of carbon on the bonding surface is determined by gas chromatography mass spectrometry (GC-MS). Etc. can be confirmed.

  In addition, the “state in which the organic matter is adsorbed” refers to a state in which the organic matter is adsorbed on the surface of the wafer during cleaning or dry storage.

  In this bonded SOI wafer manufacturing method, the state in which the organic matter is adsorbed on the wafer surface before the bonding can be obtained by cleaning the wafer surface in an atmosphere containing the organic matter.

  Moreover, in the manufacturing method of the bonded SOI wafer, the state in which the organic matter is adsorbed on the wafer surface before the bonding can also be obtained by drying the cleaned wafer in an atmosphere containing the organic matter.

  Furthermore, in the method for manufacturing a bonded SOI wafer, the state in which the organic matter is adsorbed on the wafer surface before the bonding can be obtained by treating the wafer surface with a cleaning liquid containing the organic matter.

  Furthermore, in the method for manufacturing a bonded SOI wafer, the state in which the organic matter is adsorbed on the wafer surface can also be obtained by applying or dropping a treatment liquid containing the organic matter on the wafer surface.

  (2) A bonded SOI wafer comprising a support wafer and an SOI layer bonded on the support wafer via an oxide film, wherein the bonded wafer is made of SiC and has a gettering action. A bonded SOI wafer characterized by having a crystal defect.

  In this bonded SOI wafer, the size of crystal defects can be defined as 5 to 50 nm. That is, crystal defects are extremely small. Here, the “size of crystal defect” refers to the length of the longest part of the defect from the projected image when the crystal defect is observed with a transmission electron microscope (TEM) (see FIG. 4 described later). The size that can be certified as.

Moreover, this bonded SOI wafer is a bonded SOI wafer in which a carbon concentration peak of 5 × 10 ¹⁸ atoms / cm ³ or more is detected at the bonded interface. The “carbon concentration peak” here is a result of measuring the bonded interface by secondary ion mass spectrometry (SIMS) (see FIG. 5A shown later).

  The method for producing a bonded SOI wafer according to the present invention is a method in which an active layer wafer and a support wafer are bonded together with an organic substance adsorbed on the wafer surface, a bonding strengthening heat treatment is performed, and crystal defects are formed at the bonded interface. It is. According to this method, a simple and inexpensive gettering source can be formed at the interface between the SOI layer and the insulator layer (oxide film).

  The bonded SOI wafer of the present invention has minute crystal defects made of SiC at the bonding interface and having a gettering action, and effectively removes heavy metal impurities that adversely affect device characteristics and oxide film breakdown voltage characteristics. be able to.

It is a flowchart which illustrates typically the process of the principal part in the manufacturing method of the bonding SOI wafer of this invention. It is a flowchart which shows typically the example of another process in the manufacturing method of the bonding SOI wafer of this invention. It is a flowchart which shows typically the example of another process in the manufacturing method of the bonding SOI wafer of this invention. It is a figure which shows typically the observation result by the transmission electron microscope (TEM) of the bonding interface (cross section) after giving joint strengthening heat processing, (a) is N-methyl-2 in the atmosphere at the time of wash | cleaning a wafer. -When pyrrolidone is included, (b) is not included. It is a figure which illustrates the measurement result of carbon (C) by secondary ion mass spectrometry (SIMS) in the vicinity of the bonding interface after performing joint strengthening heat treatment, and (a) is N in the atmosphere at the time of cleaning a wafer. When -methyl-2-pyrrolidone is included, (b) is not included.

  Hereinafter, the manufacturing method of the bonded SOI wafer of the present invention (1) and the bonded SOI wafer of (2) will be specifically described with reference to the drawings.

  In the method for producing a bonded SOI wafer according to the present invention (1), when an active layer wafer to be an SOI layer and a support wafer are bonded together via an oxide film, organic substances are adsorbed on the wafer surface before bonding. It is a method characterized by forming crystal defects at the bonding interface by performing bonding strengthening heat treatment in a state where the organic matter is confined at the bonding interface. The “wafer surface before bonding” refers to either or both of the active layer wafer and the support wafer.

  FIG. 1 is a flowchart schematically illustrating main steps in the method for manufacturing a bonded SOI wafer of the present invention. Below, it demonstrates along step 1-step 5.

  In step 1, an active layer wafer 12 to be an SOI layer and a support wafer 11 having an oxide film (insulating layer) 13 formed on the surface are prepared. These two wafers may be produced according to conventional methods.

  In Step 2, when the active layer wafer 12 and the support wafer 11 are bonded together, the organic matter is adsorbed on the surface of the wafer before bonding (here, the active layer wafer 12 and the support wafer 11 are indicated), that is, A natural oxide film 14 containing carbon is formed. In the support wafer 11, the natural oxide film 14 is also formed on the oxide film 13 on the surface.

  This is because a crystal defect that functions as a gettering source is formed at the bonding interface in the subsequent bonding strengthening heat treatment. Details will be described in step 4.

  The following method is effective as a specific method for bringing the wafer surface into a state where the organic matter is adsorbed.

  One is a method of cleaning the wafer surface in an atmosphere containing an organic substance. In the manufacture of bonded SOI wafers, before bonding the wafers, pre-bonding cleaning is performed by SC-1 cleaning using a mixed solution of ammonium hydroxide and hydrogen peroxide solution in order to remove surface impurities. However, the cleaning is performed in the atmosphere.

  Examples of organic substances to be used include organic substances such as aromatic hydrocarbons, chlorinated hydrocarbons, alcohols, acetate esters, ketones, ethers, etc., and may contain trace amounts of carbon. N-methyl-2-pyrrolidone is preferred. N-methyl-2-pyrrolidone is a wax remover used for preventing wrinkles when polishing a wafer during wafer processing, and thus is easily available and easily adsorbed on the wafer surface.

  By washing before bonding in this organic substance-containing atmosphere, the organic substance can be adsorbed on the wafer surface. It is considered that the effect of forming crystal defects at the bonding interface is manifested by a very small amount of organic substance adhering (adsorbing) to the wafer surface.

  Table 1 shows the results of measurement of the total amount of organic substances deposited on the surface of the wafer subjected to SC-1 cleaning in an atmosphere containing N-methyl-2-pyrrolidone as an organic substance. The amount of organic substances was measured by gas chromatograph mass spectrometry (GC-MS). In addition, about 80% of the total amount of attached organic substances is N-methyl-2-pyrrolidone. In Table 1, “with oxide film of 0.5 μm” means a wafer having an oxide film (insulating layer) with a thickness of 0.5 μm formed on the surface.

  As shown in Table 1, the surfaces of wafers (samples No. 1 and No. 2) cleaned in an atmosphere containing N-methyl-2-pyrrolidone are in an atmosphere not containing N-methyl-2-pyrrolidone. It can be seen that more than 100 times as many organic substances (that is, N-methyl-2-pyrrolidone) were detected as compared with the wafers cleaned with (No. 3 and No. 4). Further, it is considered that the amount of N-methyl-2-pyrrolidone attached is not significantly affected by the presence or absence of an oxide film (insulating layer).

  Subsequently, in Step 3, the active layer wafer 12 in a state where organic substances are adsorbed on the surface, that is, in a state where the natural oxide film 14 containing carbon is formed, is supported on the surface where the natural oxide film 14 containing carbon is also formed. The surface of the oxide film 13 of the wafer 11 is bonded to the support wafer 11 as a bonding surface. Thereby, the said organic substance will be in the state confined by the bonding interface.

  In step 4, a joint strengthening heat treatment is performed in a state where the organic substance is confined to the bonding interface. This is a heat treatment for ensuring the bonding strength and forming minute crystal defects at the bonding interface. The processing temperature is preferably 1100 ° C. or higher so that the oxide film is softened and the effect of filling the voids is obtained. The upper limit of the treatment temperature is preferably 1300 ° C. from the viewpoint of preventing the occurrence of slip dislocation.

  By this treatment, the natural oxide film containing a small amount of organic matter (carbon) at the bonding interface locally aggregates. A small amount of organic substance (carbon) aggregated with local aggregation of the natural oxide film forms a minute crystal defect 15 having a size of 50 nm or less. This crystal defect 15 is assumed to be composed of “carbon-Si (SiC)”.

  FIG. 4 is a diagram schematically showing a result of observation by a transmission electron microscope (TEM) of a bonding interface (cross section) after performing the above-described bonding strengthening heat treatment, as a result of investigation performed in Examples described later. (A) is a case where N-methyl-2-pyrrolidone is included in the atmosphere when cleaning the wafer, and (b) is a case where it is not included.

  As indicated by white arrows in FIG. 4A, when N-methyl-2-pyrrolidone is contained in the wafer cleaning atmosphere, the active layer wafer (SOI layer) 12 and the oxidized layer are oxidized by heat treatment. A minute crystal defect 15 is formed at the bonding interface of the film 13. The size is estimated to be about 50 nm or less from the comparison with the scale representing the length of 0.5 μm shown in FIG. On the other hand, when N-methyl-2-pyrrolidone is not contained in the atmosphere, formation of crystal defects is not recognized (FIG. 4B).

  FIG. 5 shows the results of the measurement of the carbon (C) concentration by secondary ion mass spectrometry (SIMS) in the vicinity of the bonding interface after performing the above-described bonding strengthening heat treatment, similarly to the results of the investigation conducted in the example. FIG. (A) is a case where N-methyl-2-pyrrolidone is included in the atmosphere when cleaning the wafer, and (b) is a case where it is not included.

In FIG. 5, the horizontal axis represents the distance from the active layer wafer (SOI layer) side to the support wafer side (herein referred to as “depth”) in the bonded SOI wafer after performing the bonding strengthening heat treatment. Along the horizontal axis, the SOI layer, the oxide film, and the existing portion of the support wafer (support substrate) are shown in the figure. The vertical axis represents the carbon concentration (atoms / cm ³ ). The carbon concentration indicated by the white arrow A is the background level of the carbon concentration in the wafer, and the carbon concentration similarly indicated by the white arrow B is the background level of the carbon concentration in the oxide film (insulating layer).

As shown in FIG. 5A, when N-methyl-2-pyrrolidone is contained in the atmosphere during wafer cleaning, carbon is bonded at the bonding interface between the active layer wafer (SOI layer) and the oxide film (insulating layer). It can be seen that the concentration shows a peak, and a carbon (C) peak of 2 × 10 ²⁰ atoms / cm ³ is detected. On the other hand, when N-methyl-2-pyrrolidone is not contained in the atmosphere, such a remarkable carbon (C) peak is obtained at any depth as shown in FIG. Not detected (only a carbon (C) peak of less than 5 × 10 ¹⁸ atoms / cm ³ is observed at the bonding interface). In other words, the amount of organic matter may be adjusted so that the organic matter is adsorbed on the wafer surface before pasting so that a carbon peak of 5 × 10 ¹⁸ atoms / cm ³ or more is obtained at the pasting interface.

  Step 5 is a process for thinning the active layer wafer (SOI layer) 12. In this step, the bonded SOI wafer 10 is manufactured by reducing the film thickness according to conventional methods such as machining and chemical etching.

  FIG. 2 is a flowchart schematically showing another process example in the method for manufacturing a bonded SOI wafer of the present invention.

  1 is different from the process shown in FIG. 1 in step 2, when the active layer wafer 12 and the support wafer 11 are bonded to each other, only the surface of the active layer wafer 12 is adsorbed with organic substances, that is, carbon is removed. The point is that a natural oxide film 14 is formed.

  In step 3, the active layer wafer 12 having the carbon-containing natural oxide film 14 formed on the surface is supported by using the oxide film 13 surface of the support wafer 11 on which the carbon-containing natural oxide film 14 is not formed as a bonding surface. Affixed to the wafer 11.

  FIG. 3 is a flowchart schematically showing still another process example in the method for manufacturing a bonded SOI wafer of the present invention. When the active layer wafer 12 and the support wafer 11 are bonded together, only the surface of the support wafer 11 is applied. This is the case where the organic substance is adsorbed, that is, the natural oxide film 14 containing carbon is formed.

  As a specific method for making the organic substance adsorbed on the surface of the wafer performed in the above step 2, in addition to the above-described method of cleaning the wafer surface in an atmosphere containing the organic substance before bonding, cleaning is performed. A method of drying a later wafer in an atmosphere containing an organic substance is also effective. In addition, a method of treating the wafer surface with a cleaning liquid containing an organic substance is also effective. When manufacturing wafers, not only the pre-bonding cleaning, but also various pickling and cleaning to remove impurities and fine particles on the wafer surface, pickling solution and cleaning solution used at that time An organic substance is added to this.

  Furthermore, a method of applying or dropping a treatment liquid containing an organic substance on the wafer surface is also applicable. It is also effective to apply a spin coating technique to spread the processing solution thinly and evenly on the wafer surface.

  Even when these methods are applied, the concentration of organic substances is not particularly limited because crystal defects can be formed by a very small amount of adhesion to the wafer surface.

  In this way, the surface of the wafer or the surface of the oxide film (insulating layer) formed on it is cleaned in an atmosphere containing organic matter, etc., and the surface of the wafer is naturally oxidized containing a small amount of organic matter (carbon). By forming a film so as to be confined to the bonding interface and subsequently performing heat treatment, minute crystal defects can be formed at the bonding interface.

  This crystal defect has a gettering action of removing heavy metal impurities resulting from the process from the active region of the integrated circuit. This can be confirmed by improving the oxide film breakdown voltage characteristics of the device formed on the SOI layer surface of the SOI wafer manufactured by the above-described method.

  As described above, according to the method for manufacturing a bonded SOI wafer of the present invention, an active layer wafer (SOI layer) and an insulator layer (oxidation layer) can be used as a simple and inexpensive gettering source without adding a special process. Film).

  Next, the bonded SOI wafer of the present invention (2) will be described.

  This bonded SOI wafer can be manufactured, for example, by the method of the present invention described above. This bonded SOI wafer has minute crystal defects due to carbon at the bonding interface. As described with reference to Table 1 and FIGS. 4 and 5, the crystal defects present at the bonding interface are crystal defects caused by carbon.

  In this bonded SOI wafer, the crystal defects are extremely small as schematically shown in FIG. Therefore, it is possible to specify the bonded SOI wafer of the present invention by defining the crystal defect size as 5 to 50 nm.

  The bonded SOI wafer of the present invention having such minute crystal defects can effectively remove heavy metal impurities that adversely affect device characteristics and oxide film breakdown voltage characteristics.

Further, the bonded SOI wafer of the present invention has a characteristic carbon in which a carbon concentration peak of 5 × 10 ¹⁸ atoms / cm ³ or more is detected at the bonded interface as shown in FIG. 5 (a). A concentration distribution is obtained. That is, it is possible to specify the bonded SOI wafer of the present invention by defining the value of the carbon concentration peak at the bonded interface.

  A bonded SOI wafer was produced by applying the method of the present invention, and the effect of the method for manufacturing a bonded SOI wafer of the present invention was confirmed.

Example 1
A bonded SOI wafer was manufactured as follows in accordance with the steps of the flowchart shown in FIG.

  That is, using an active layer wafer 12 as an SOI layer and a support wafer 11 having a surface formed with an oxide film 13 having a thickness of 1.0 μm, SC-1 is used in an atmosphere containing N-methyl-2-pyrrolidone as an organic substance. Cleaning before bonding of the surface of the wafer (in this case, the active layer wafer 12 and the support wafer 11) was performed. In SC-1 cleaning, the cleaning solution was replenished with a chemical solution so that the concentrations of ammonium hydroxide and hydrogen peroxide water were always constant, and the cleaning solution was circulated through a filter. The temperature of the cleaning liquid was 75 ° C. and the cleaning time was 10 minutes.

  Then, the active layer wafer 12 and the support wafer 11 are bonded together at room temperature, and then heat treatment is performed at a processing temperature of 1100 ° C. or higher, and the SOI layer is thinned to 5.0 μm by grinding and polishing. A wafer was produced.

  FIG. 4 schematically shows the observation result of the bonding interface (cross section) of this SOI wafer by a transmission electron microscope (TEM). As shown in FIG. 4 (a), the active layer wafer 12 and A minute crystal defect 15 of 5 to 50 nm was formed at the bonding interface of the oxide film 13.

Further, the measurement result of carbon (C) concentration by secondary ion mass spectrometry (SIMS) of this SOI wafer is shown in FIG. 5, and as shown in FIG. 5 (a), the active layer wafer (SOI layer) and the oxidized layer were oxidized. A carbon (C) peak of 2 × 10 ²⁰ atoms / cm ³ indicating the presence of carbon was detected at the bonding interface of the film.

  On the other hand, for comparison, an SOI wafer manufactured under the same conditions as those in Example 1 except that the wafer surface pre-bonding cleaning is performed in an atmosphere not containing N-methyl-2-pyrrolidone. No crystal defects are observed at the bonding interface between the active layer wafer and the oxide film as observed with an electron microscope (TEM) (see FIG. 4B), and carbon is not detected even in secondary ion mass spectrometry (SIMS). (See FIG. 5B).

(Example 2)
A bonded SOI wafer was produced according to the steps of the flowchart shown in FIG.

  The used active layer wafer 12 and the support wafer 11 having the oxide film 13 formed on the surface thereof are the same as those used in Example 1. In addition, other conditions including the method of forming the natural oxide film 14 containing carbon on the surface of the wafer (in this case, the active layer wafer 12) were the same as in the case of Example 1.

Observation of the bonded interface (cross section) of the manufactured SOI wafer with a transmission electron microscope (TEM) and measurement of carbon (C) concentration by secondary ion mass spectrometry (SIMS) were carried out in Example 1 described above. Compared to the SOI wafer, only the surface of the active layer wafer 12 is in a state where the organic matter is adsorbed, so that the amount of organic matter is small, and thus a tendency for the peak value of the carbon concentration to decrease slightly is observed. A minute crystal defect 15 of 50 nm was observed, and a carbon (C) peak of 1 × 10 ²⁰ atoms / cm ³ was detected.

(Example 3)
A bonded SOI wafer was produced according to the steps of the flowchart shown in FIG.

  The active layer wafer 12 used and the support wafer 11 having the oxide film 13 formed on the surface thereof are the same as those used in Example 1. The method for forming the natural oxide film 14 containing carbon on the surface of the wafer (here, the support wafer 11) and other conditions were also the same as in the case of Example 1.

  The bonding interface (cross section) of the manufactured SOI wafer was observed with a transmission electron microscope (TEM) and measured for carbon (C) concentration by secondary ion mass spectrometry (SIMS). A result equivalent to that of the SOI wafer was obtained.

  According to the method for manufacturing a bonded SOI wafer of the present invention, an active layer wafer and a support wafer are bonded to each other with an organic substance adsorbed on the wafer surface, and bonding strengthening heat treatment is performed to form crystal defects at the bonded interface. Thus, a simple and inexpensive gettering source can be formed at the interface between the SOI layer and the insulator layer (oxide film). Moreover, the bonded SOI wafer of the present invention can effectively remove heavy metal impurities that adversely affect device characteristics and oxide film breakdown voltage characteristics.

  Therefore, the manufacturing method of the present invention and the bonded SOI wafer of the present invention can be widely used as an SOI wafer excellent in device characteristics or a manufacturing method thereof.

10: Bonded SOI wafer 11: Support wafer
12: Active layer wafer, SOI layer 13: Oxide film 14: Natural oxide film 15: Crystal defects

Claims (9)

After bonding an active layer wafer to be an SOI layer and a support wafer through an oxide film, the active layer wafer is thinned to produce a bonded SOI wafer in which an SOI layer is formed on a buried oxide film. In the way to
Bonding is performed in a state in which organic substances are adsorbed on the wafer surface before bonding, and a crystal defect is formed at the bonding interface by performing bonding strengthening heat treatment in a state where the organic substances are confined in the bonding interface. A method for manufacturing a bonded SOI wafer. 2. The method for producing a bonded SOI wafer according to claim 1, wherein a carbon concentration peak of 5 × 10 ¹⁸ atoms / cm ³ or more is detected at the bonded interface after the bonding strengthening heat treatment.   The bonded SOI according to claim 1 or 2, wherein the state in which the organic substance is adsorbed on the wafer surface before bonding is obtained by drying the wafer after cleaning in an atmosphere containing the organic substance. Wafer manufacturing method.   The method for producing a bonded SOI wafer according to any one of claims 1 to 3, wherein the size of the crystal defect is 5 to 50 nm.   The method for producing a bonded SOI wafer according to any one of claims 1 to 4, wherein the organic substance is N-methyl-2-pyrrolidone.   The temperature of the said joint reinforcement | strengthening heat processing is 1100 degreeC or more, The manufacturing method of the bonding SOI wafer in any one of Claims 1-5 characterized by the above-mentioned. A support wafer;
A bonded SOI wafer comprising an SOI layer bonded via an oxide film on the support wafer,
A bonded SOI wafer characterized in that it has minute crystal defects made of SiC and having a gettering action at the bonded interface.   The bonded SOI wafer according to claim 7, wherein a size of the crystal defect is 5 to 50 nm. 9. The bonded SOI wafer according to claim 7, wherein a carbon concentration peak of 5 × 10 ¹⁸ atoms / cm ³ or more is detected at the bonded interface.

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