JP5644670B2 - Manufacturing method of bonded SOI wafer - Google Patents

Description

  The present invention relates to a method for manufacturing a bonded SOI wafer using an ion implantation separation method, and more particularly to a method for manufacturing a bonded SOI wafer having a step of forming an epitaxial layer on the surface of a thin film SOI layer after separation.

  As one of semiconductor device wafers, there is an SOI (Silicon On Insulator) wafer in which a silicon layer is formed on a silicon oxide film that is an insulating film. In this SOI wafer, a silicon layer (hereinafter sometimes referred to as an SOI layer) in the surface layer portion of the substrate serving as a device manufacturing region is electrically separated from the inside of the substrate by a buried oxide film layer (BOX layer). It has features such as small capacity and high radiation resistance. Therefore, effects such as high-speed and low-power consumption operation and prevention of soft errors are expected, and it is promising as a substrate for high-performance semiconductor elements.

Typical methods for manufacturing this SOI wafer include a wafer bonding method and a SIMOX method.
In the wafer bonding method, for example, after forming a thermal oxide film on one surface of two silicon single crystal wafers, the two wafers are brought into close contact with each other through the formed thermal oxide film, and a bonding heat treatment is performed. In this method, the bonding force is increased, and then one wafer (a wafer on which an SOI layer is formed (hereinafter referred to as a bond wafer)) is thinned by mirror polishing or the like to manufacture an SOI wafer. As a method for thinning, a bond wafer is ground and polished to a desired thickness, or at least one of hydrogen ions or rare gas ions is implanted into the bond wafer in advance to form an ion implantation layer. There is a method called an ion implantation separation method in which the bond wafer is separated from the ion implantation layer after bonding.

  On the other hand, in the SIMOX method, oxygen is ion-implanted into a single crystal silicon substrate, and then a high-temperature heat treatment (oxide film formation heat treatment) is performed to react the implanted oxygen and silicon to form a BOX layer (buried oxide film layer). This is a method for manufacturing an SOI substrate by forming a substrate.

Of the two typical methods described above, the wafer bonding method has the advantage that the thickness of the SOI layer and BOX layer to be fabricated can be set freely, so it can be applied to various device applications. It is.
In particular, the ion implantation delamination method, which is one of the wafer bonding methods, has the characteristics of having excellent film thickness uniformity in addition to the above-described advantages, and can obtain stable device characteristics over the entire wafer surface. However, when the thickness of the SOI layer is as thick as several μm, it cannot be handled by the ion implantation separation method alone due to the limitation of the maximum acceleration voltage of the ion implanter. As a method for solving this, there is a method of performing epi-growth on the surface of a bonded wafer produced by an ion implantation separation method (Patent Document 1). By using this method, the thickness of the SOI layer can be freely set to several μm, and at the same time, it is possible to obtain a high uniformity of the SOI layer thickness that cannot be obtained with a bonded wafer by a grinding / polishing method. I can do it.

  On the other hand, in a bonded SOI wafer manufactured by an ion implantation separation method, an epitaxial layer having a normal resistivity (about 1 to 20 Ωcm) is formed thereon using a low resistivity SOI layer as a seed layer due to demands on the device structure. In some cases, an SOI wafer is required.

  Incidentally, it is known that the bonded SOI wafer is warped in a convex shape on the SOI layer side due to its cross-sectional structure. When this warpage becomes large, it becomes a cause of defects in a photolithography process of the device manufacturing process. Therefore, in order to suppress the warping of the bonded SOI wafer, in Patent Documents 2 and 3, warping in which the bonding surface side has a concave shape is formed in advance on the base wafer before bonding. Have been described. Patent Document 4 describes that warpage can be reduced by adjusting the oxide film thickness on the upper and lower surfaces (bonding surface side and back surface side) of the base wafer of the manufactured bonded SOI wafer.

JP 2000-30995 A Japanese Patent Laid-Open No. 3-55822 JP 2009-302163 A Japanese Patent Laid-Open No. 03-250615

Even when a bonded SOI wafer is manufactured by an ion implantation separation method, the SOI layer side warps in a convex shape due to the cross-sectional structure, but when an SOI layer is formed by an ion implantation separation method, the formed SOI layer Is a thin film of 1 μm or less (in many cases, several 100 nm or less), and as described in Patent Document 4, equivalent oxide films are formed on the upper and lower surfaces (bonded surface side and back surface side) of the base wafer. By doing so, warpage can be sufficiently reduced.
However, it has been found that when an epitaxial layer is formed on the surface of the SOI layer of a bonded SOI wafer manufactured by the ion implantation separation method, the SOI wafer is greatly warped.

  The present invention has been made in view of the above problems, and occurs when an epitaxial layer is formed on the surface of a thin film SOI layer after peeling in a method for manufacturing a bonded SOI wafer using an ion implantation peeling method. It aims at providing the method of suppressing curvature.

In order to solve the above problems, in the present invention, an ion implantation layer is formed in the bond wafer by ion-implanting at least one gas ion of hydrogen or a rare gas from the surface of a bond wafer made of a silicon single crystal, After bonding the ion-implanted surface of the bond wafer and the surface of the base wafer through an insulating film, a thin-film SOI layer is formed by peeling the bond wafer with the ion-implanted layer, and then on the surface of the thin-film SOI layer. In the method of manufacturing a bonded SOI wafer for depositing an epitaxial layer,
The thin film SOI layer is formed as a p ⁺ type thin film by using, as the bond wafer, a silicon single crystal wafer having a resistivity of 0.1 Ωcm or less with boron as a dopant in a region from the surface to at least the depth at which the ion implantation layer is formed. In order to suppress warpage that occurs when the resistivity of the epitaxial layer deposited on the surface of the p ⁺ type thin film SOI layer is higher than 0.1 Ωcm, the p before formation of the epitaxial layer is formed. Provided is a method for manufacturing a bonded SOI wafer, wherein the shape of an SOI wafer having a ⁺ -type thin film SOI layer is adjusted.

As described above, an SOI wafer in which an epitaxial layer having a normal resistivity (about 1 to 20 Ωcm) is formed thereon using a low resistivity SOI layer formed by an ion implantation delamination method as a seed layer due to requirements on the device structure. May be required. However, when an epitaxial layer having a higher resistivity is formed on the surface of a p ⁺ type thin film SOI layer having a resistivity of 0.1 Ωcm or less and having a resistivity of 0.1 Ωcm or less formed by the ion implantation delamination method, warping is caused. May occur.
If it is the manufacturing method of the bonded SOI wafer of this invention, the surface of the thin film SOI layer formed by the ion implantation peeling method is adjusted by adjusting the shape of the SOI wafer which has the p ⁺ type thin film SOI layer before epitaxial layer formation It is possible to suppress warping that occurs when an epitaxial layer is formed.

At this time, it is preferable that the shape of the SOI wafer having the p ⁺ type thin film SOI layer before the formation of the epitaxial layer is adjusted to a flat or concave shape.

Warpage that occurs when an epitaxial layer having a higher resistivity is formed on the surface of a low resistivity p ⁺ type thin film SOI layer having a resistivity of 0.1 Ωcm or less, because the SOI layer side has a convex shape. It is preferable to make the shape of the SOI wafer having the p ⁺ type thin film SOI layer before forming the epitaxial layer flat or concave, since the convex warpage can be surely suppressed.

At this time, the shape of the SOI wafer having the p ⁺ type thin film SOI layer before the epitaxial layer formation can be adjusted by using a silicon single crystal wafer having a concave shape on the bonding surface side as the base wafer. preferable.
Further, it is preferable to adjust the shape of the SOI wafer having the p ⁺ type thin film SOI layer before forming the epitaxial layer by forming a silicon oxide film on the back surface of the base wafer.

As described above, as a method for adjusting the shape of the SOI wafer having the p ⁺ type thin film SOI layer before forming the epitaxial layer, a method of using a wafer having a concave shape on the bonding surface side as a base wafer, and the back surface of the base wafer And a method of forming a silicon oxide film.

At this time, it is preferable that the resistivity of the p ⁺ type thin film SOI layer is 0.01 Ωcm or less and the resistivity of the epitaxial layer is 1 Ωcm or more.

As described above, when the resistivity of the p ⁺ type thin film SOI layer is 0.01 Ωcm or less, if an epitaxial layer having a resistivity of 1 Ωcm or more is formed, the warpage is remarkably increased. Therefore, the bonded SOI wafer of the present invention is manufactured. The method can be suitably used.

  As described above, according to the bonded SOI wafer manufacturing method of the present invention, in the bonded SOI wafer manufacturing method using the ion implantation peeling method, the epitaxial layer is deposited on the surface of the thin film SOI layer after peeling. Warpage that occurs in some cases can be suppressed.

The process flowchart which showed an example of the manufacturing method of the bonding SOI wafer of this invention is shown. The process flowchart which showed another example of the manufacturing method of the bonding SOI wafer of this invention is shown. In an experimental example, it is the figure which compared the magnitude | size of the curvature at the time of depositing an epitaxial layer in the SOI layer (seed layer) from which the resistivity formed by the ion implantation peeling method using the bond wafer from which resistivity differs.

Hereinafter, the present invention will be described in more detail.
The inventors of the present invention manufactured an SOI wafer having SOI layers with different resistivity by an ion implantation delamination method, and deposited an epitaxial layer using an SOI layer with a different resistivity as a seed layer, before forming the epitaxial layer. Although the warpage of the SOI wafer is almost the same, it has been found that the warpage of the SOI wafer using the SOI layer having a low resistivity as a seed layer becomes larger after the formation of the epitaxial layer.
As a result of detailed investigations by the inventors, the problem that the SOI wafer greatly warps when an epitaxial layer is formed is that the SOI layer is p ⁺ type (resistivity is 0.1 Ωcm or less, especially boron) as a dopant. Is 0.01 Ωcm or less) and the resistivity of the epitaxial layer is higher than that of the SOI layer as the seed layer (more than 0.1 Ωcm, particularly 1 Ωcm or more), the SOI layer side It has been found that it is warped to have a convex shape.

In general, when an epitaxial layer is formed on a normal silicon single crystal wafer that is not an SOI wafer, warping occurs if the resistance value of the epitaxial growth silicon wafer is different from the resistance value of the epitaxial layer. This is a phenomenon that has been observed (Patent Document 3 etc.).
However, in the case of a bonded SOI wafer manufactured by an ion implantation separation method, the p ⁺ type SOI layer is a thin film of about several hundred nm, and an insulating film such as a silicon oxide film of the same thickness is formed below the p ⁺ type SOI layer. Thus, even if a base wafer (usually resistivity) having a thickness 1000 times or more that of the SOI layer exists, the SOI layer side has a convex shape only by forming an epitaxial layer of several μm on the SOI layer. It was a phenomenon that even those skilled in the art had not predicted that the direction would greatly warp.

The phenomenon that the warpage increases due to epitaxial growth on the surface of the p ⁺ type thin film SOI layer of the SOI wafer produced by the ion implantation delamination method is the phenomenon that occurs on the p ⁺ type thin film SOI layer (seed layer) having a small lattice constant. Further, this is caused by growing an epitaxial layer having a larger lattice constant than that. Although the p ⁺ type thin film SOI layer manufactured by the ion implantation delamination method is as thin as about 100 nm, each interface of the p ⁺ type thin film SOI layer / insulating film layer / base wafer is strongly bonded. It can be regarded as equivalent to a p ⁺ -type silicon single crystal wafer (p ⁺ -type wafer), and in the same manner as when an epitaxial layer is formed on a normal silicon single crystal wafer having no SOI structure, the p ⁺ -type thin film SOI layer and the epitaxial layer are epitaxially formed. If the resistivity of the layer is different, warping is considered to occur.

In the present invention, in order to suppress warping of the SOI wafer after the epitaxial layer is deposited using the p ⁺ type thin film SOI layer formed by the ion implantation separation method as a seed layer, the p ⁺ before the epitaxial layer formation is suppressed. The shape of the SOI wafer having the mold thin film SOI layer is adjusted. The present invention will be described in detail below.

1 and 2 are process flow diagrams showing an example of a method for manufacturing a bonded SOI wafer according to the present invention.
In the present invention, at least one gas ion of hydrogen or a rare gas is ion-implanted from the surface of a bond wafer 1 made of a silicon single crystal to form an ion-implanted layer 2 in the bond wafer 1 (FIG. 1A ), (B)), the ion-implanted surface of the bond wafer 1 and the surface of the base wafer 3 are bonded together via an insulating film 4 (FIG. 1C), and the bond wafer 1 is bonded with the ion-implanted layer 2. After forming the thin film SOI layer 5 by peeling (FIG. 1 (d)), an epitaxial layer 6 is deposited on the surface of the thin film SOI layer 5 (FIG. 1 (e)). A silicon single crystal wafer having a resistivity of 0.1 Ωcm or less with boron as a dopant in a region from the surface to at least the depth at which the ion-implanted layer is formed is bonded to the bond wafer. The thin film SOI layer 5 and ^{p +} -type thin film SOI layer 5 by using a C 1, a high resistivity resistivity than 0.1Ωcm of the epitaxial layer 6 is deposited on the surface of the ^{p +} -type thin film SOI layer 5 In order to suppress the warpage that occurs when the epitaxial layer is formed, the shape of the SOI wafer 10 having the p ⁺ type thin film SOI layer 5 before the formation of the epitaxial layer is adjusted.

First, in FIG. 1A, a bond wafer 1 and a base wafer 3 made of a silicon single crystal are prepared.
Here, in the method for manufacturing a bonded SOI wafer according to the present invention, the ion implantation layer 2 is formed in the bond wafer 1 in a later step (FIG. 1B). At this time, at least the ion implantation is performed from the surface. A silicon single crystal wafer having a resistivity with boron as a dopant in the region up to the depth at which the layer 2 is formed is 0.1 Ωcm or less is used as the bond wafer 1. A silicon single crystal wafer having a resistivity of 0.1 Ωcm or less is used as the bond wafer 1, and the bond wafer 1 is peeled off by the ion implantation layer 2 in a subsequent process (FIG. 1D), thereby forming a p ⁺ type thin film SOI layer. 5 is manufactured.
As such a bond wafer 1, a CZ silicon single crystal wafer in which the entire wafer is doped with boron and has a resistivity of 0.1 Ωcm or less can be used, but the surface has a desired thickness of 0.1 Ωcm or less. A silicon epitaxial wafer having a boron-doped epitaxial layer can also be used. The lower limit of the resistivity is not particularly limited, but can be 0.005 Ωcm or more in consideration of crystallinity.

The present invention suppresses the warpage that occurs when the epitaxial layer 6 having a resistivity higher than 0.1 Ωcm is deposited on the surface of the p ⁺ -type thin film SOI layer 5, so that the p ⁺ before the epitaxial layer formation is suppressed. The shape of the SOI wafer 10 having the mold thin film SOI layer 5 is adjusted. Although the upper limit of the resistivity of the epitaxial layer 6 is not specifically limited, For example, it can be set to 100 Ωcm or less.

As a method for adjusting the shape of the SOI wafer 10 having the p ⁺ type thin film SOI layer 5, as shown in FIG. 1A, a silicon single crystal wafer having a concave shape on the bonding surface side is used as the base wafer 3. A method is mentioned. Further, as shown in FIG. 2A, the shape of the SOI wafer 10 having the p ⁺ type thin film SOI layer 5 before the epitaxial layer formation is adjusted by forming the silicon oxide film 7 on the back surface of the base wafer 3 ′. You can also
The silicon oxide film 7 can be formed on the back surface of the base wafer 3 ′ by a CVD method or the like.

  Next, as shown in FIGS. 1B and 2B, an insulating film 4 is formed on at least one of the bond wafer 1 and the base wafer 3 (3 ′), here, the bond wafer 1. The thickness and the like of the insulating film 4 should be determined according to specifications and are not particularly limited. For example, the insulating film 4 (oxide film) having a thickness of about 0.01 to 2.0 μm by thermal oxidation. Can be formed.

  Next, at least one gas ion of hydrogen or a rare gas is ion-implanted from the surface of the bond wafer 1 to form an ion-implanted layer 2 in the bond wafer 1. If ion implantation is performed through the insulating film 4 as shown in FIGS. 1B and 2B, an effect of suppressing channeling of implanted ions can be obtained.

  Next, in FIG. 1C and FIG. 2C, the ion-implanted surface of the bond wafer 1 and the surface of the base wafer 3 (3 ′) are bonded together via the insulating film 4. Normally, the wafers are bonded to each other without using an adhesive or the like by bringing the surfaces of the bond wafer 1 and the base wafer 3 (3 ') into contact with each other in a clean atmosphere at room temperature.

Next, in FIGS. 1D and 2D, the thin film SOI layer 5 is formed by peeling the bond wafer 1 with the ion implantation layer 2. In the present invention, a silicon single crystal wafer having a resistivity of 0.1 Ωcm or less with boron as a dopant in the region from the surface to at least the depth at which the ion-implanted layer 2 is formed is used as a bond wafer 1, thereby forming a p ⁺ type. The SOI wafer 10 having the thin film SOI layer 5 is obtained.
Although it does not specifically limit as this peeling method, For example, the bond wafer 1 can be peeled by performing the heat processing at about 500-600 degreeC with respect to the bonded wafer, for example by inert gas atmosphere. Alternatively, the peeling surface may be planarized to obtain an SOI wafer 10 having the p ⁺ type thin film SOI layer 5. As the planarization treatment, there are generally known planarization by CMP (Chemical Mechanical Polishing), planarization by high-temperature heat treatment in a reducing gas or inert gas atmosphere, or planarization heat treatment in an atmosphere containing hydrogen chloride gas. It has been.

In the present invention, as shown in FIGS. 1A and 2A, a silicon single crystal wafer having a concave shape on the bonding surface side is used as the base wafer, or a silicon oxide film 7 is formed on the back surface of the base wafer. In order to adjust the shape of the SOI wafer 10 having the p ⁺ type thin film SOI layer 5 by such a method as described above, even if an epitaxial layer 6 having a resistivity higher than 0.1 Ωcm is deposited in the next step, warpage is suppressed. Is possible. Note that the shape of the SOI wafer 10 having the p ⁺ -type thin film SOI layer 5 is preferably adjusted to be flat or concave.

Thereafter, an epitaxial layer 6 having a resistivity higher than 0.1 Ωcm is deposited on the surface of the p ⁺ -type thin film SOI layer 5 obtained as described above (FIG. 1E), and FIG. )). In the present invention, since the shape of the SOI wafer 10 having the p ⁺ type thin film SOI layer 5 before the epitaxial layer formation is adjusted, the warpage of the SOI wafer after deposition can be suppressed.

  EXAMPLES The present invention will be described in more detail below with reference to experimental examples, examples of the present invention, and comparative examples, but these do not limit the present invention.

(Experimental example)
As a bond wafer for producing an SOI wafer by an ion implantation separation method, a p ⁺ wafer having a diameter of 300 mm and a conductivity type p-type (boron doped) having different resistivity is used, and the resistivity of the p ⁺ type SOI layer (seed layer) is Several different SOI wafers (BOX layer thickness 150 nm, SOI layer thickness 150 nm, base wafer thickness 775 μm, no backside oxide film on the base wafer) are produced, and an epitaxial layer having a resistivity of 10 Ωcm is formed at 1080 ° C. on the surface of the SOI layer. After forming 5 μm, warpage of the SOI wafer was measured using AFS3220 manufactured by KLA-Tencor.
When the seed layer has a low resistivity (0.1 Ωcm or less) and the resistivity of the epitaxial layer is higher than that of the SOI layer (a resistivity higher than 0.1 Ωcm), the SOI layer side warps in a convex shape. It was. FIG. 3 also shows that the warp after epitaxial growth increases as the resistivity of the seed layer is lower (particularly 0.01 Ωcm or less). (All SOI wafers had a convex shape on the SOI layer side.)

(Example 1) When a silicon single crystal wafer having a concave shape on the bonding surface side is used as a base wafer As a bond wafer for producing an SOI wafer by an ion implantation delamination method, a diameter of 300 mm, a crystal orientation <100>, conductivity After preparing a p-type (boron doped), mirror-polished silicon single crystal wafer with a resistivity of 8.5 mΩcm, forming an oxide film with a thickness of 150 nm by thermal oxidation, 5 × 10 ¹⁶ / cm of hydrogen ions are formed from the oxide film surface. A dose of ² was injected into the surface layer of the bond wafer.
On the other hand, a mirror-polished silicon single crystal wafer having a diameter of 300 mm, a crystal orientation <100>, a conductivity type p-type (boron doped), and a resistivity of 10 Ωcm was prepared as a base wafer. This base wafer has a concave shape on the bonding surface side, and is produced so as to intentionally have a warp of 50 μm when the wafer is sliced from a silicon single crystal rod.

After bonding the ion-implanted surface of the bond wafer and the concave-side surface of the base wafer via an oxide film, the surface is peeled off by the ion-implanted layer by heat treatment in a non-oxidizing atmosphere, and the release surface is flat. An SOI wafer having a thin film SOI layer with a thickness of 150 nm was manufactured. The manufactured SOI wafer was concave on the SOI layer side and the warpage was 10 μm.
A 3.5 μm epitaxial layer (resistivity 10 Ωcm) was formed on the surface of the SOI layer at 1080 ° C., and the warpage was measured. As a result, the SOI layer side was convex and the warpage was as small as 10 μm. .

(Example 2) When a CVD oxide film is formed on the back surface of a base wafer As a bond wafer for producing an SOI wafer by an ion implantation delamination method, a diameter of 300 mm, a crystal orientation <100>, a conductivity type p-type (boron doped), A mirror-polished silicon single crystal wafer having a resistivity of 8.5 mΩcm is prepared, an oxide film having a thickness of 150 nm is formed by thermal oxidation, and then a bond wafer at a dose of 5 × 10 ¹⁶ / cm ² with hydrogen ions from the oxide film surface. It was injected into the surface layer part.
On the other hand, as a base wafer, a mirror-polished silicon single crystal wafer having a diameter of 300 mm, a conductivity type p-type (boron doped), a crystal orientation <100>, and a resistivity of 10 Ωcm is prepared, and a 1 μm CVD oxide film is formed on the back surface. Oita.

After bonding the ion-implanted surface of the bond wafer and the surface of the base wafer (surface without the CVD oxide film) through an oxide film, the surface is peeled off by an ion-implanted layer by heat treatment in a non-oxidizing atmosphere. Then, the peeled surface was planarized to produce an SOI wafer having a 150 nm SOI layer. The manufactured SOI wafer had a concave shape on the SOI layer side and a warp size of 12 μm.
A 3.5 μm epitaxial layer (resistivity 10 Ωcm) was formed on the surface of this SOI layer at 1080 ° C., and the warpage was measured. As a result, the SOI layer side had a convex shape and the warpage was an extremely small value of 11 μm. .

(Comparative Example 1) When a normal mirror wafer is used as a base wafer As a bond wafer for producing an SOI wafer by an ion implantation delamination method, a diameter of 300 mm, a crystal orientation <100>, a conductive p-type (boron-doped), a resistance After preparing a mirror-polished silicon single crystal wafer with a rate of 8.5 mΩcm and forming an oxide film with a thickness of 150 nm by thermal oxidation, hydrogen ions are applied from the oxide film surface at a dose of 5 × 10 ¹⁶ / cm ² . It inject | poured into the surface layer part.

On the other hand, a mirror-polished silicon single crystal wafer having a diameter of 300 mm, a conductive p-type (boron doped), a crystal orientation <100>, and a resistivity of 10 Ωcm was prepared as a base wafer.
After bonding the ion-implanted surface of the bond wafer and the surface of the base wafer via an oxide film, heat treatment is performed in a non-oxidizing atmosphere to peel off the ion-implanted layer, and the surface to be peeled is flattened. Then, an SOI wafer having a thin film SOI layer of 150 nm was manufactured. The produced SOI wafer had a convex shape on the SOI layer side and a warp size of 40 μm.
A 3.5 μm epitaxial layer (resistivity 10 Ωcm) was formed on the surface of this SOI layer at 1080 ° C., and the warpage was measured. As a result, the SOI layer side was convex and the warpage size was 63 μm, and the warpage amount was greatly deteriorated. did.

Thus, a silicon single crystal wafer having a concave shape on the bonding surface side is used as the base wafer as in the first embodiment, or a silicon oxide film is formed on the back surface of the base wafer as in the second embodiment. This occurs when the epitaxial layer is formed on the surface of the thin film SOI layer formed by using the ion implantation separation method by adjusting the shape of the SOI wafer having the p ⁺ type thin film SOI layer before the epitaxial layer formation. Warpage can be suppressed.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

DESCRIPTION OF SYMBOLS 1 ... Bond wafer, 2 ... Ion implantation layer 3, 3 '... Base wafer, 4 ... Insulating film, 5 ... P ⁺ type thin film SOI layer (thin film SOI layer), 6 ... Epitaxial layer, 7 ... Silicon oxide film, 10 ... SOI wafer having p ⁺ type thin film SOI layer.

Claims (4)

At least one gas ion of hydrogen or a rare gas is ion-implanted from the surface of a bond wafer made of silicon single crystal to form an ion-implanted layer in the bond wafer, and the ion-implanted surface of the bond wafer and the base wafer The thin film SOI layer is formed by peeling the bond wafer with the ion-implanted layer, and then depositing an epitaxial layer on the surface of the thin film SOI layer. In the manufacturing method,
The thin film SOI layer is formed as a p ⁺ type thin film by using, as the bond wafer, a silicon single crystal wafer having a resistivity of 0.01 Ωcm or less with boron as a dopant in a region from the surface to at least the depth at which the ion implantation layer is formed. A method for manufacturing the bonded SOI wafer by setting the resistivity of the epitaxial layer to be an SOI layer and the epitaxial layer deposited on the surface of the p ⁺ type thin film SOI layer is 1 Ωcm or more;
Such a thin-film SOI layer is a p ⁺ type SOI layer having a resistivity of 0.01 Ωcm or less using boron as a dopant , and suppresses warping that occurs when the resistivity of the epitaxial layer is 1 Ωcm or more. Therefore, method for producing a bonded SOI wafer and adjusting the shape of the SOI wafer having the p ⁺ -type thin film SOI layer before the epitaxial layer forming. 2. The method for manufacturing a bonded SOI wafer according to claim 1, wherein the shape of the SOI wafer having the p ⁺ -type thin film SOI layer before the formation of the epitaxial layer is adjusted to a flat or concave shape. The shape of the SOI wafer having the p ⁺ type thin film SOI layer before the formation of the epitaxial layer is adjusted by using a silicon single crystal wafer having a concave shape on the bonding surface side as the base wafer. The manufacturing method of the bonding SOI wafer of Claim 1 or Claim 2. The shape of the SOI wafer having the p ⁺ type thin film SOI layer before the epitaxial layer formation is adjusted by forming a silicon oxide film on the back surface of the base wafer. The manufacturing method of the bonding SOI wafer of description.

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