JP7566119B1 - Composite substrate and method for manufacturing the same - Google Patents

Abstract

The present invention provides a composite substrate in which a functional substrate and a supporting substrate are bonded via a bonding layer, which is capable of obtaining sufficient bonding strength even if the bonding layer is thin, and a method for manufacturing the same.
[Solution] A composite substrate 100 has a functional substrate 10 made of a functional material, and a support substrate 30 made of a semiconductor material and bonded to the functional substrate 10 to support the functional substrate 10. The functional substrate 10 has a first layer, and a second layer made of an amorphous body containing a rare gas, which is disposed closer to the support substrate 30 than the first layer. The support substrate 30 has a first support layer, a second support layer made of an amorphous body of a semiconductor material containing a rare gas, which is disposed closer to the functional substrate 10 than the first support layer, and a bonding layer made of an amorphous body of a semiconductor material, which is in contact with the functional substrate 10.
[Selected Figure] Figure 1

Description

The present invention relates to a composite substrate and a manufacturing method thereof.

Conventionally, a composite substrate is known that is formed by bonding a functional substrate made of a piezoelectric material such as LN (LiNbO ₃ : lithium niobate) or LT (LiTaO ₃ : lithium tantalate) to a support substrate made of a semiconductor material such as Si, and is used for applications such as surface acoustic wave devices. As a method for producing such a composite substrate, a method is known in which the bonding surfaces of the functional substrate and the support substrate are activated by irradiating them with a fast atom beam (FAB) and then directly bonded to each other. However, this method has a problem in that the bonding strength between the substrates is low and there is a risk of peeling off during a processing step after bonding.

The technology of Patent Document 1 is known to solve the above problem. Patent Document 1 describes a method for manufacturing a composite substrate by irradiating a support substrate with a high-speed atomic beam to sputter the semiconductor material of the support substrate, thereby forming a bonding layer made of an amorphous semiconductor material on the piezoelectric substrate by amorphizing the semiconductor material, and then pressure-bonding the piezoelectric substrate and support substrate via this bonding layer. This method improves the bonding strength between the piezoelectric substrate and support substrate, and prevents peeling after bonding.

Patent No. 7152711

In a composite substrate in which a functional substrate such as a piezoelectric substrate and a support substrate are bonded, it is preferable from the viewpoint of productivity that the sputtering time is as short as possible, and shortening the sputtering time results in a thinner bonding layer. On the other hand, in order to obtain the desired bonding strength in a conventional bonding method such as that in Patent Document 1, a certain thickness is required for the bonding layer.

The present invention has been made in view of the above, and its main objective is to provide a composite substrate in which a functional substrate and a support substrate are bonded via a bonding layer, and a manufacturing method thereof that can provide sufficient bonding strength even if the bonding layer is thin.

A composite substrate according to a first aspect of the present invention comprises a functional substrate made of a functional material, and a support substrate made of a semiconductor material and bonded to the functional substrate to support the functional substrate, the functional substrate comprising a first functional layer made of a crystal of the functional material , and a second functional layer arranged closer to the support substrate than the first functional layer and made of an amorphous body of the functional material containing a rare gas, the support substrate comprising a first support layer, a second support layer arranged closer to the functional substrate than the first support layer and made of an amorphous body of the semiconductor material containing the rare gas, and a bonding layer in contact with the functional substrate and made of the amorphous body of the semiconductor material, the bonding layer containing the rare gas, and the content of the rare gas in the bonding layer is less than the content of the rare gas in the second support layer .
A composite substrate according to a second aspect of the present invention comprises a functional substrate made of a functional material, and a support substrate made of a semiconductor material and bonded to the functional substrate to support the functional substrate, the functional substrate being bonded to the support substrate via an insulating layer made of an insulating material, the support substrate comprising a first support layer, a second support layer arranged closer to the functional substrate than the first support layer and made of an amorphous body of the semiconductor material containing a rare gas, and a bonding layer made of the amorphous body of the semiconductor material in contact with the insulating layer, the insulating layer comprising a first insulating layer made of the insulating material and a second insulating layer made of the amorphous body of the insulating material and in contact with the bonding layer, the bonding layer containing the rare gas, and a content of the rare gas in the bonding layer being less than a content of the rare gas in the second support layer.
A manufacturing method for a composite substrate according to a third aspect of the present invention is a manufacturing method for a composite substrate including a functional substrate made of a functional material and a support substrate made of a semiconductor material and supporting the functional substrate, the manufacturing method including: an activation step of irradiating a surface of the functional substrate and a surface of a semiconductor substrate made of the semiconductor material with a fast atomic beam so that at least a part of the irradiation times of the functional substrate and the semiconductor substrate are overlapped; a sputtering step, which is performed following the activation step, in which after stopping the irradiation of the fast atomic beam on the surface of the functional substrate, the irradiation of the fast atomic beam on the surface of the semiconductor substrate is continued to form a sputtered film made of an amorphous body of the sputtered semiconductor material on the surface of the functional substrate; and a bonding step of bonding the functional substrate on which the sputtered film has been formed and the semiconductor substrate to obtain a bonded body.
A manufacturing method for a composite substrate according to a fourth aspect of the present invention is a manufacturing method for a composite substrate including a functional substrate made of a functional material and a support substrate made of a semiconductor material and supporting the functional substrate, and includes an insulating layer forming step of forming an insulating layer made of an insulating material on a surface of the functional substrate, an activation step of irradiating a fast atomic beam onto the surface of the insulating layer and a surface of a semiconductor substrate made of the semiconductor material such that at least a portion of the irradiation times of the respective surfaces overlap, a sputtering step that is performed following the activation step, in which after stopping the irradiation of the fast atomic beam onto the surface of the insulating layer, the irradiation of the fast atomic beam onto the surface of the semiconductor substrate is continued to sputter the semiconductor material onto the surface of the insulating layer, and a bonding step of bonding the functional substrate and the semiconductor substrate via the insulating layer onto which the semiconductor material has been sputtered by the sputtering step to obtain a bonded body.

The present invention provides a composite substrate in which a functional substrate and a support substrate are bonded via a bonding layer, and a manufacturing method thereof that can provide sufficient bonding strength even if the bonding layer is thin.

1 is a schematic cross-sectional view showing a schematic configuration of a composite substrate according to a first embodiment of the present invention. 3A to 3C are diagrams illustrating an example of a manufacturing process for the composite substrate according to the first embodiment of the present invention. 3A to 3C are diagrams illustrating an example of a manufacturing process for the composite substrate according to the first embodiment of the present invention. FIG. 4 is a schematic cross-sectional view showing a schematic configuration of a composite substrate according to a second embodiment of the present invention. 7A to 7C are diagrams illustrating an example of a manufacturing process for a composite substrate according to a second embodiment of the present invention. 7A to 7C are diagrams illustrating an example of a manufacturing process for a composite substrate according to a second embodiment of the present invention. FIG. 11 is a schematic cross-sectional view showing a schematic configuration of a composite substrate according to a third embodiment of the present invention. FIG. 11 is a schematic cross-sectional view showing a schematic configuration of a composite substrate according to a fourth embodiment of the present invention. FIG. 2 is a diagram showing observation photographs of Example 1 and a comparative example. 1 is a table showing EDX analysis results of Examples 1 and 3. 1 is a table showing the relationship between FAB irradiation time, thickness of a bonding layer, and bonding strength in a composite substrate. 1 is a table showing the relationship between FAB irradiation time and bonding strength for a functional substrate and a semiconductor substrate in a composite substrate.

The following describes embodiments of the present invention with reference to the drawings, but the present invention is not limited to these embodiments. In addition, in order to make the description clearer, the drawings may show the width, thickness, shape, etc. of each part more diagrammatically than the embodiments, but these are merely examples and do not limit the interpretation of the present invention.

First Embodiment
1 is a schematic cross-sectional view showing a schematic configuration of a composite substrate according to a first embodiment of the present invention. The composite substrate 100 in this embodiment is used for various purposes such as optical elements constituting an optical waveguide, piezoelectric elements constituting a surface acoustic wave (SAW) filter, various semiconductor elements, etc., and has a structure in which a functional substrate 10 made of a functional material such as a piezoelectric material or a semiconductor material is bonded to a support substrate 30.

The material of the functional substrate 10 may be, for example, a piezoelectric material such as LN (LiNbO ₃ : lithium niobate), LT (LiTaO ₃ : lithium tantalate), quartz, AlN (aluminum nitride), or PZT (Pb(Zr,Ti)O ₃ : lead zirconate titanate). The material of the functional substrate 10 may be selected arbitrarily depending on the application of the composite substrate 100. For example, the functional substrate 10 may be made of semiconductor materials such as SiC, InP, GaN, GaP, and diamond, materials having an electro-optic effect such as lithium niobate-lithium tantalate and KTP (potassium titanate phosphate), quartz, or glass, in addition to the piezoelectric material. In addition, the functional substrate 10 made of various functional materials may be used depending on the application of the composite substrate 100.

The support substrate 30 supports the functional substrate 10. Any suitable substrate may be used as the support substrate 30. The support substrate 30 may be composed of a single crystal body or a polycrystalline body. The functional substrate 10 and the support substrate 30 are directly bonded to each other.

The material constituting the support substrate 30 may be a semiconductor material such as Si, Ge, SiC, InP, GaN, or sapphire. Alternatively, the support substrate 30 may be made of Si(1-x)Ox (where 0.008≦x≦0.408) or SOI (Silicon on Insulator). The thickness of the support substrate 30 is, for example, 0.2 to 1 mm, but any other appropriate thickness may be adopted.

Although not shown, the composite substrate 100 may further include any layer. The type, function, number, combination, arrangement, etc. of such layers may be appropriately set according to the purpose.

The composite substrate 100 may be manufactured in any suitable shape. In one embodiment, the composite substrate 100 may be manufactured in the form of a so-called wafer. The size of the composite substrate 100 may be appropriately set according to the purpose, for example, the diameter of the wafer (substrate) may be 50 mm to 150 mm.

Figures 2 and 3 are diagrams showing an example of a manufacturing process for a composite substrate according to the first embodiment of the present invention.

Figure 2 (a) shows the preparation step in the manufacturing process of the composite substrate 100. In this step, a functional substrate 10 made of a functional material with a predetermined thickness is prepared.

Figure 2(b) shows the activation step in the manufacturing process of the composite substrate 100. In this step, for example, a semiconductor substrate 30A made of a semiconductor material of a predetermined thickness is prepared, and activation processing is performed by irradiating the surfaces of the functional substrate 10 prepared in the preparation step of Figure 2(a) and the semiconductor substrate 30A with a fast atomic beam (hereinafter referred to as FAB) using a rare gas such as Ar as the atomic species for a predetermined period of time. The FAB irradiation time at this time is preferably about 15 to 30 seconds, for example.

Figure 2 (c) shows the sputtering step in the manufacturing process of the composite substrate 100. In this step, the FAB irradiation on the functional substrate 10 side is stopped, and the FAB irradiation on the semiconductor substrate 30A side is continued for a further predetermined time, out of the FAB irradiated to the functional substrate 10 and the semiconductor substrate 30A in the activation step of Figure 2 (b). The FAB irradiation time at this time is preferably, for example, about 30 to 600 seconds. As a result, the semiconductor material constituting the semiconductor substrate 30A is sputtered and attached to the surface of the functional substrate 10, and a sputtered film 30B made of the same semiconductor material as the semiconductor substrate 30A is formed on the functional substrate 10 side. As described later, the thickness of the bonding layer 33 (see Figure 3 (f)) in the composite substrate 100 after manufacture is preferably 0.3 nm or more and 3 nm or less, and therefore, in the sputtering step, it is preferable to form the sputtered film 30B with a thickness of 0.3 nm or more and 3 nm or less.

Figure 3(d) shows the bonding process in the manufacturing process of the composite substrate 100. In this process, the functional substrate 10 on which the sputtered film 30B was formed in the sputtering process of Figure 2(c) is bonded to the semiconductor substrate 30A. As a result, the semiconductor substrate 30A and the sputtered film 30B are integrated to form the support substrate 30, and a bonded body of the functional substrate 10 and the support substrate 30 is obtained. Note that in Figure 3(d) and subsequent figures, the positional relationship between the functional substrate 10 and the semiconductor substrate 30A (support substrate 30) is illustrated upside down compared to Figures 2(a) to 2(c).

Figure 3(e) shows the bonded body obtained after the bonding process of Figure 3(d). By the bonding process of Figure 3(d), the semiconductor substrate 30A and the sputtered film 30B are integrated as described above, forming a support substrate 30 having a bonding interface 40 therein, and a bonded body as shown in Figure 3(e) is obtained.

In the bonded body of FIG. 3(e), the functional substrate 10 is provided with a first functional layer 11 mainly composed of a crystalline body of a functional material, and a second functional layer 12 arranged on the support substrate 30 side from the first functional layer 11. The second functional layer 12 is mainly composed of an amorphous body of a functional material, and is a layer containing rare gas atoms such as Ar irradiated as FAB in the activation process of FIG. 2(b). On the other hand, the support substrate 30 is provided with a first support layer 31 that does not contact the bonding interface 40, a second support layer 32 that is arranged on the functional substrate 10 side from the first support layer 31 and contacts the bonding interface 40, and a bonding layer 33 that is arranged on the functional substrate 10 side from the second support layer 32 and contacts the bonding interface 40. The second support layer 32 is mainly composed of an amorphous body of a semiconductor material, and is a layer containing rare gas atoms such as Ar irradiated as FAB in the activation process of FIG. 2(b) and the sputtering process of FIG. 2(c). The bonding layer 33 corresponds to the sputtered film 30B before bonding, and is a layer that forms the bonding portion with the functional substrate 10.

The second functional layer 12 in the functional substrate 10, and the second support layer 32 and bonding layer 33 in the support substrate 30 may contain other atomic species that are mixed into these layers during the sputtering process in FIG. 2(c), such as Fe atoms and Al atoms that constitute the jig or base portion used to fix the semiconductor substrate 30A. Details of these layers will be described later.

Figure 3(f) shows the thinning process in the manufacturing process of the composite substrate 100. In this process, the functional substrate 10 is polished to a predetermined thickness to thin the bonded body shown in Figure 3(e). For example, the functional substrate 10 can be polished to thin the bonded body by grinding, CMP (Chemical Mechanical Polish), surface planarization using a gas cluster ion beam, or the like.

Through the above steps, a composite substrate 100 having the structure shown in Figure 1 is manufactured.

Between the bonding step of FIG. 3(d) and the thin plate processing step of FIG. 3(f), an annealing step may be performed in which the bonded body is heated to a predetermined temperature. The heating temperature at this time is preferably, for example, about 75 to 250°C, and more preferably 100 to 250°C. This can improve the bonding strength of the functional substrate 10.

Second Embodiment
4 is a schematic cross-sectional view showing a schematic configuration of a composite substrate according to a second embodiment of the present invention. A composite substrate 110 according to this embodiment has a structure in which a functional substrate 10 is bonded to a support substrate 30 via an insulating layer 20, as compared with the composite substrate 100 shown in FIG. 1 described in the first embodiment.

The insulating layer 20 made of an insulating material is disposed between the functional substrate 10 and the support substrate 30. The insulating material constituting the insulating layer 20 may be, for example, an oxide or nitride of Si, Ta, Al, Nb, Hf, etc., and is preferably silicon oxide.

The insulating layer 20 can be formed by any suitable method. For example, it can be formed by physical vapor deposition such as sputtering, vacuum deposition, ion beam assisted deposition (IAD), chemical vapor deposition, or atomic layer deposition (ALD). The insulating layer 20 can be formed at, for example, room temperature (25°C) to 300°C.

In this embodiment, as in the first embodiment described above, the composite substrate 110 may further include any layer. The type, function, number, combination, arrangement, etc. of such layers may be appropriately set depending on the purpose. In addition, the composite substrate 110 may be manufactured in any appropriate shape depending on the purpose.

Figures 5 and 6 are diagrams showing an example of a manufacturing process for a composite substrate according to the second embodiment of the present invention.

Figure 5(a) shows the preparation step in the manufacturing process of the composite substrate 110. In this step, a functional substrate 10 of a predetermined thickness is prepared, similar to the step in Figure 2(a) described in the first embodiment.

Figure 5 (b) shows the insulating layer formation process in the manufacturing process of the composite substrate 110. In this process, an insulating layer 20 is formed by depositing, for example, an amorphous silicon oxide film of a predetermined thickness on the surface of the functional substrate 10 prepared in the preparation process of Figure 5 (a).

Figure 5(c) shows the activation step in the manufacturing process of the composite substrate 110. In this step, for example, a semiconductor substrate 30A made of a semiconductor material of a predetermined thickness is prepared, and activation processing is performed on the surface of the insulating layer 20 formed on the functional substrate 10 in the insulating layer formation step of Figure 5(b) and the semiconductor substrate 30A by irradiating the respective surfaces with FAB using a rare gas such as Ar as the atomic species for a predetermined time, as in the step of Figure 2(b) described in the first embodiment.

Figure 5 (d) shows the sputtering step in the manufacturing process of the composite substrate 110. In this step, as in the step of Figure 2 (c) described in the first embodiment, the FAB irradiation of the functional substrate 10 side (insulating layer 20 side) of the FAB irradiated to the functional substrate 10 and the semiconductor substrate 30A in the activation step of Figure 5 (c) is stopped, and the FAB irradiation of the semiconductor substrate 30A side is continued for a further predetermined time. As a result, the semiconductor material constituting the semiconductor substrate 30A is sputtered and attached to the surface of the insulating layer 20 formed on the functional substrate 10, and a sputtered film 30B made of the same semiconductor material as the semiconductor substrate 30A is formed on the functional substrate 10 side (insulating layer 20 side). As in the first embodiment, the thickness of the bonding layer 33 (see Figure 6 (g)) in the composite substrate 110 after manufacture is preferably 0.3 nm or more and 3 nm or less, and therefore, in the sputtering step, it is preferable to form the sputtered film 30B with a thickness of 0.3 nm or more and 3 nm or less.

Figure 6(e) shows the bonding process in the manufacturing process of the composite substrate 110. In this process, similar to the process of Figure 3(d) described in the first embodiment, the functional substrate 10 on which the sputtered film 30B has been formed on the insulating layer 20 in the sputtering process of Figure 5(d) is bonded to the semiconductor substrate 30A. As a result, the semiconductor substrate 30A and the sputtered film 30B are bonded and integrated to form the support substrate 30, and a bonded body of the functional substrate 10, the insulating layer 20, and the support substrate 30 is obtained. Note that in Figure 6(e) and subsequent figures, the positional relationship between the functional substrate 10 and the semiconductor substrate 30A (support substrate 30) is illustrated upside down compared to Figures 5(a) to 5(d).

Figure 6(f) shows the bonded body obtained after the bonding process of Figure 6(e). By the bonding process of Figure 6(e), the semiconductor substrate 30A and the sputtered film 30B are integrated as described above, forming a support substrate 30 having a bonding interface 40 therein, and a bonded body as shown in Figure 6(f) is obtained.

In the bonded body of FIG. 6(f), the insulating layer 20 is formed with a first insulating layer 21 mainly made of an insulating material, and a second insulating layer 22 arranged closer to the support substrate 30 than the first insulating layer 21. The second insulating layer 22 is mainly made of an amorphous insulating material, and is a layer containing rare gas atoms such as Ar irradiated as FAB in the activation process of FIG. 5(c). On the other hand, the support substrate 30 is formed with a first support layer 31 that does not contact the bonding interface 40, a second support layer 32 that is arranged closer to the functional substrate 10 than the first support layer 31 and contacts the bonding interface 40, and a bonding layer 33 that is arranged closer to the functional substrate 10 than the second support layer 32 and contacts the bonding interface 40, as in the first embodiment.

Figure 6(g) shows the thin plate processing step in the manufacturing process of the composite substrate 110. In this step, similar to the step of Figure 3(f) described in the first embodiment, the functional substrate 10 is polished to a predetermined thickness for the bonded body shown in Figure 6(f) to thin it.

Through the above steps, a composite substrate 110 having the structure shown in Figure 4 is manufactured.

In this embodiment, as in the first embodiment, an annealing step of heating the bonded body to a predetermined temperature may be performed between the bonding step in FIG. 6(e) and the thin plate processing step in FIG. 6(g).

Third Embodiment
7 is a schematic cross-sectional view showing a schematic configuration of a composite substrate according to a third embodiment of the present invention. A composite substrate 120 according to this embodiment has a structure in which a functional substrate 10 is directly bonded to a support substrate 30, similar to the composite substrate 100 shown in FIG. 1 described in the first embodiment.

In the composite substrate 120 of this embodiment, a ridge portion 50 is provided on the functional substrate 10 in order to use a part of the functional substrate 10 as an optical waveguide. The ridge portion 50 is a portion of the functional substrate 10 that is formed to have a greater thickness than other portions by providing a step in the functional substrate 10. The ridge portion 50 is provided by performing a process (ridge processing) to form a step in a part of the functional substrate 10 after the thin plate processing process of FIG. 3(f) described in the first embodiment. For example, the ridge processing of the functional substrate 10 can be realized by processing using laser light or dry etching such as RIE (Reactive Ion Etching). Other processes may be performed after that. As a result, the bonding interface 40 is included inside the support substrate 30 in this embodiment as well.

Fourth Embodiment
Fig. 8 is a schematic cross-sectional view showing a schematic configuration of a composite substrate according to a fourth embodiment of the present invention. A composite substrate 130 according to this embodiment has a structure in which a functional substrate 10 is bonded to a support substrate 30 via an insulating layer 20, similar to the composite substrate 110 shown in Fig. 4 described in the second embodiment.

The material and shape of the functional substrate 10 are the same as those described in the third embodiment. That is, in the composite substrate 130 of this embodiment, a ridge portion 50 is provided in the functional substrate 10 in order to use a portion of the functional substrate 10 as an optical waveguide. The ridge portion 50 is provided by performing processing (ridge processing) to form a step in a portion of the functional substrate 10 after the thin plate processing step of FIG. 6(g) described in the second embodiment, for example. As a result, the bonding interface 40 is included inside the support substrate 30 in this embodiment as well.

Below, we will explain in detail the examples for verifying the structure of the composite substrate according to the present invention. Note that, unless otherwise specified, the following procedures were carried out at room temperature.

Example 1
A bonded body was produced according to the manufacturing process described with reference to Fig. 2 and Fig. 3. Specifically, an LT substrate and a silicon substrate each having a diameter of 4 inches and a thickness of 500 µm were prepared, and the LT substrate was used as the functional substrate 10, and the silicon substrate was used as the semiconductor substrate 30A.

Then, after cleaning the surfaces of the functional substrate 10 and the semiconductor substrate 30A, the functional substrate 10 and the semiconductor substrate 30A were arranged in a vacuum chamber in which FAB guns were installed facing upward and downward, so that the substrates were located within the irradiation ranges of the FAB guns and the surfaces of the two substrates faced each other. In this state, the vacuum chamber was evacuated to the ^10-6 Pa range, and FAB (acceleration voltage 1 kV, Ar flow rate 27 sccm) using Ar gas was irradiated from each FAB gun toward the surfaces of the functional substrate 10 and the semiconductor substrate 30A simultaneously for 15 seconds.

Then, the FAB irradiation on the functional substrate 10 side was stopped, while the FAB irradiation on the semiconductor substrate 30A side was continued for another 90 seconds (total of 105 seconds). In order to prevent the internal pressure of the vacuum chamber from changing before and after the FAB irradiation on the functional substrate 10 side was stopped, the FAB irradiation from the FAB gun on the functional substrate 10 side to the surface of the functional substrate 10 was stopped while the supply of Ar gas to the FAB gun on the functional substrate 10 side was continued. As a result, a sputtered film 30B was formed on the surface of the functional substrate 10.

Next, the functional substrate 10 on which the sputtered film 30B was formed was directly bonded to the semiconductor substrate 30A. Specifically, the beam-irradiated surfaces of both substrates were overlapped, and the two substrates were bonded together by applying a pressure of 10,000 N at room temperature for 2 minutes to obtain a bonded body. This resulted in a composite substrate 100 having the structure shown in FIG. 1.

The bonding strength of the composite substrate 100 thus obtained was evaluated by a crack opening method and found to be 1.45 J/m ² , which was sufficient.

Example 2
A functional substrate 10 and a semiconductor substrate 30A similar to those in Example 1 were placed in a vacuum chamber, and the vacuum chamber was evacuated to the 10 ⁻⁶ Pa range. With the vacuum chamber evacuated to the 10 −6 Pa range, FAB using Ar gas was irradiated simultaneously from each FAB gun to the surfaces of the functional substrate 10 and the semiconductor substrate 30A for 30 seconds under the same conditions as in Example 1.

Then, the FAB irradiation on the functional substrate 10 side was stopped, while the FAB irradiation on the semiconductor substrate 30A side was continued for another 90 seconds (total of 120 seconds). At this time, as in Example 1, in order to prevent the internal pressure of the vacuum chamber from changing before and after the FAB irradiation on the functional substrate 10 side was stopped, while the supply of Ar gas to the FAB gun on the functional substrate 10 side was continued, the FAB irradiation from the FAB gun to the surface of the functional substrate 10 was stopped. As a result, a sputtered film 30B was formed on the surface of the functional substrate 10.

Next, similarly to Example 1, the functional substrate 10 on which the sputtered film 30B was formed was directly bonded to the semiconductor substrate 30A to obtain a composite substrate 100 having the structure shown in FIG. 1.

The bonding strength of the composite substrate 100 thus obtained was evaluated by a crack opening method, and was found to be 1.63 J/m ² , which was an improvement over that of Example 1.

Example 3
A bonded body was produced according to the manufacturing process described with reference to Figures 5 and 6. Specifically, an LT substrate and a silicon substrate, each having a diameter of 4 inches and a thickness of 500 µm, were prepared, and the LT substrate was used as the functional substrate 10, and the silicon substrate was used as the semiconductor substrate 30A. Silicon oxide was then sputtered onto the surface of the functional substrate 10 to form an insulating layer 20 made of a silicon oxide film.

Thereafter, similarly to Example 1, the surfaces of the functional substrate 10 and the semiconductor substrate 30A on which the insulating layer 20 was formed were cleaned, and then, in a vacuum chamber in which FAB guns were installed facing upward and downward, the functional substrate 10 and the semiconductor substrate 30A were arranged so that these substrates were located within the irradiation range of each FAB gun and the silicon oxide surface (the surface on the insulating layer 20 side) of the functional substrate 10 and the surface of the semiconductor substrate 30A faced each other. In this state, the vacuum chamber was evacuated to the order of 10 ^-6 Pa, and FAB using Ar gas was irradiated simultaneously for 15 seconds from each FAB gun toward the surfaces of the functional substrate 10 and the semiconductor substrate 30A under the same conditions as in Example 1.

Then, the FAB irradiation on the functional substrate 10 side was stopped, while the FAB irradiation on the semiconductor substrate 30A side was continued for another 285 seconds (300 seconds in total). At this time, as in Examples 1 and 2, in order to prevent the internal pressure of the vacuum chamber from changing before and after the FAB irradiation on the functional substrate 10 side was stopped, while the supply of Ar gas to the FAB gun on the functional substrate 10 side was continued, and the FAB irradiation from the FAB gun to the surface of the functional substrate 10 was stopped. As a result, a sputtered film 30B was formed on the surface of the insulating layer 20 in the functional substrate 10.

Next, similarly to Examples 1 and 2, the functional substrate 10 having the sputtered film 30B formed on the surface of the insulating layer 20 was directly bonded to the semiconductor substrate 30A to obtain a composite substrate 110 having the structure shown in FIG. 4.

The bonding strength of the composite substrate 110 thus obtained was evaluated by a crack opening method and found to be 2.01 J/ ^m2 , which was an even greater improvement than that of Examples 1 and 2.

In the above Examples 1 to 3, the FAB irradiation from the FAB gun to the functional substrate 10 and the semiconductor substrate 30A is performed for a predetermined time, and then the FAB irradiation on the functional substrate 10 side is stopped first. This allows the time required for forming the sputtered film 30B to be used for cooling the functional substrate 10, thereby reducing the effect of warping on the composite substrates 100, 110 after bonding. In particular, when the functional substrate 10 has a larger thermal expansion coefficient than the semiconductor substrate 30A, stopping the FAB irradiation on the functional substrate 10 side first can be more effective in reducing warping after bonding.

Comparative Example
In order to confirm the effect of the present invention, as a comparative example, a functional substrate 10 and a semiconductor substrate 30A similar to those in Example 1 were placed in a vacuum chamber, and in a state in which the inside of the vacuum chamber was evacuated to the ^10-6 Pa range, FAB irradiation was not performed on the functional substrate 10 side, and only FAB irradiation on the semiconductor substrate 30A side was performed for 90 seconds. The FAB irradiation conditions on the semiconductor substrate 30A side at this time were the same as those in Example 1. As a result, a sputtered film 30B was formed on the surface of the insulating layer 20 in the functional substrate 10.

Next, similarly to Examples 1 to 3, the functional substrate 10 on which the sputtered film 30B was formed was directly bonded to the semiconductor substrate 30A to obtain a composite substrate 100 having the structure shown in FIG. 1.

When the bonding strength of the composite substrate 100 thus obtained was evaluated by a crack opening method, it was 0.74 J/m ² , which was not a sufficient bonding strength.

(Confirmation of laminated structure)
A cross section including the bonding interface 40 of the composite substrate 100 produced in each of Example 1 and Comparative Example was observed with a transmission electron microscope (TEM) to confirm the layered structure of the composite substrate 100. Fig. 9(a) shows an observation photograph of Example 1, and Fig. 9(b) shows an observation photograph of the Comparative Example.

9(a) shows that two layers are formed inside the functional substrate 10. These layers are called the first functional layer 11 and the second functional layer 12, in order from the side farthest from the support substrate 30. It can also be seen that three layers are formed inside the support substrate 30. These layers are called the first support layer 31, the second support layer 32, and the bonding layer 33, in order from the side farthest from the functional substrate 10. The second functional layer 12 and the bonding layer 33 are in contact with each other, and the bonding interface 40 formed in the bonding process described above exists between the second support layer 32 and the bonding layer 33. That is, in the bonding process, the surface of the second functional layer 12 in the semiconductor substrate 30A before bonding and the surface of the sputtered film 30B formed on the functional substrate 10 before bonding are bonded to each other, so that the sputtered film 30B becomes the bonding layer 33, and a bonded body of the functional substrate 10 and the support substrate 30 having the bonding interface 40 inside the support substrate 30 is formed.

From the observation photograph in Figure 9 (a), it can be seen that, while the first functional layer 11 is made of crystalline LT, the second functional layer 12 does not have a crystalline structure and is made of amorphous LT. That is, in Example 1, it can be seen that the second functional layer 12, which corresponds to the portion of the functional substrate 10 before bonding from the surface irradiated with FAB in the activation process to a predetermined depth, is formed as a layer in which LT, the material of the functional substrate 10, has been made amorphous.

Similarly, from the observation photograph of FIG. 9(a), it can be seen that, while the first support layer 31 is made of crystalline Si, the second support layer 32 and the bonding layer 33 do not have a crystalline structure and are made of amorphous Si. That is, in Example 1, the second support layer 32, which corresponds to the portion of the semiconductor substrate 30A before bonding from the surface irradiated with FAB in the activation process and the sputtering process to a predetermined depth, and the bonding layer 33, which corresponds to the sputtered film 30B formed on the surface of the functional substrate 10 in the sputtering process, are each formed as a layer of amorphous silicon, which is the material of the support substrate 30.

On the other hand, in the observation photograph of the comparative example shown in FIG. 9(b), the functional substrate 10 is composed only of a first functional layer 11 having a crystalline structure, and the second functional layer 12 as in Example 1 is not formed on the functional substrate 10. That is, in the comparative example, the functional substrate 10 before bonding is not irradiated with FAB in the activation process, so the second functional layer 12 made of an amorphous film of LT is not formed, and it can be seen that this results in a lower bonding strength than in Example 1.

As described above, in Example 3, an insulating layer 20 made of a silicon oxide film is formed on the surface of the functional substrate 10 before bonding, and the surface of this insulating layer 20 is activated, and then a sputtered film 30B is formed to bond the functional substrate 10 and the semiconductor substrate 30A. Therefore, in the composite substrate 110 of Example 3, two layers corresponding to the first functional layer 11 and the second functional layer 12 in FIG. 9(a) are formed in the insulating layer 20, not in the functional substrate 10. That is, in Example 3, a first insulating layer 21 located on the side farther from the support substrate 30 and a second insulating layer 22 corresponding to a portion of the insulating layer 20 from the surface irradiated with FAB in the activation process before bonding to a predetermined depth are formed.

(Structural Analysis)
In a cross section including the bonding interface 40 of the composite substrate 100 produced in Example 1, EDX analysis was performed on each of the first functional layer 11, the second functional layer 12, the first support layer 31, the second support layer 32, and the bonding layer 33, thereby performing a structural analysis of the composite substrate 100. Similarly, in a cross section including the bonding interface 40 of the composite substrate 110 produced in Example 3, EDX analysis was performed on each of the first insulating layer 21, the second insulating layer 22, the first support layer 31, the second support layer 32, and the bonding layer 33, thereby performing a structural analysis of the composite substrate 110.

The table in FIG. 10(a) shows the ratio of elemental components obtained from the EDX analysis results for each of the first functional layer 11, the second functional layer 12, the first support layer 31, the second support layer 32, and the bonding layer 33 in Example 1. In addition, the measurement results of the thickness of each layer are also shown for the second functional layer 12, the second support layer 32, and the bonding layer 33.

From the table in FIG. 10(a), the rare gas Ar used in the FAB irradiation is contained in greater amounts in the second functional layer 12 and the second support layer 32 than in the first functional layer 11 and the first support layer 31. The content is also higher in the second support layer 32 than in the second functional layer 12. From these results, it can be seen that the second functional layer 12 and the second support layer 32 contain Ar resulting from the FAB irradiated in the activation process and the sputtering process, respectively, and that the second support layer 32 is irradiated with FAB for a longer time than the second functional layer 12, so that the second functional layer 12 contains more Ar. Note that in the table in FIG. 10(a), the first functional layer 11 and the first support layer 31 contain a small amount of Ar, but there may be cases where they do not contain any.

On the other hand, in the table of FIG. 10(a), the Ar content in the bonding layer 33 is lower than that in the second functional layer 12 and the second support layer 32. This shows that the Ar irradiated as FAB in the sputtering process is not contained in significant amounts in the bonding layer 33, which corresponds to the sputtered film 30B.

The table in FIG. 10(a) also shows that the bonding layer 33 contains more Al than the other layers. This is thought to be because in the sputtering process, the FAB is irradiated not only onto the semiconductor substrate 30A, but also onto the jig and base that secure the semiconductor substrate 30A, causing these components to become mixed into the bonding layer 33.

The table in FIG. 10(b) shows the ratio of elemental components obtained from the EDX analysis results for each of the first insulating layer 21, the second insulating layer 22, the first supporting layer 31, the second supporting layer 32, and the bonding layer 33 in Example 3. In addition, for the second supporting layer 32 and the bonding layer 33, the measurement results of the thickness of each layer are also shown.

In the insulating layer 20 of Example 3, unlike the functional substrate 10 of Example 1, both the first insulating layer 21 and the second insulating layer 22 are made of amorphous silicon oxide, so that the boundary between the first insulating layer 21 and the second insulating layer 22 is difficult to distinguish even when looking at the TEM observation photograph. Therefore, the thickness of the second insulating layer 22 is not listed in the table of FIG. 10(b). However, in the insulating layer 20 of Example 3, similar to the functional substrate 10 of Example 1, it is considered that the second insulating layer 22 made of an amorphous body containing a large amount of Ar, like the second functional layer 12, exists in the vicinity of the bonding layer 33 (for example, within a range of about several nm from the boundary surface with the bonding layer 33). Therefore, in the table of FIG. 10(b), the EDX analysis result for the insulating layer 20 near the boundary surface with the bonding layer 33 is shown as the EDX analysis result of the second insulating layer 22.

10(a), the table in FIG. 10(b) shows that the rare gas Ar used in the FAB irradiation is contained in the second insulating layer 22 and the second supporting layer 32 in a larger amount than the first insulating layer 21 and the first supporting layer 31. The content of Ar is also higher in the second supporting layer 32 than in the second insulating layer 22. From these results, it can be seen that in Example 3 as well as in Example 1, the second insulating layer 22 and the second supporting layer 32 contain Ar resulting from the FAB irradiated in the activation process and the sputtering process, and the second insulating layer 22 contains more Ar because the second supporting layer 32 is irradiated with FAB for a longer time than the second insulating layer 22. In the table in FIG. 10(b), the first insulating layer 21 and the first supporting layer 31 contain a small amount of Ar, but there may be cases where they do not contain any Ar.

On the other hand, in the table of FIG. 10(b), the content of Ar in the bonding layer 33 is lower than that in the second insulating layer 22 and the second support layer 32. This shows that, as in Example 1, in Example 3 as well, the Ar irradiated as FAB in the sputtering process is not contained in significant amounts in the bonding layer 33 corresponding to the sputtered film 30B.

The table in Figure 10(b) also shows, as in the table in Figure 10(a), that for the reasons mentioned above, the bonding layer 33 contains more Al than the other layers.

(Relationship between bonding layer thickness and bonding strength)
Among the manufacturing parameters described in Example 3, the FAB irradiation time to the semiconductor substrate 30A in the sputtering process was changed, and the other parameters were kept the same as in Example 3. Using multiple composite substrates 110 each manufactured in this manner, the relationship between the thickness and bonding strength of the bonding layer 33 in the support substrate 30 was measured.

Figure 11 is a table showing the relationship between the FAB irradiation time, the thickness of the bonding layer 33, and the bonding strength in the composite substrate 110. The table in Figure 11 shows the FAB irradiation time to the semiconductor substrate 30A in the activation process combined with the sputtering process, and the thickness and bonding strength of the bonding layer 33 of each composite substrate 110 produced when the FAB irradiation time to the functional substrate 10 and the semiconductor substrate 30A in the activation process is fixed at 15 seconds, and the FAB irradiation time to the semiconductor substrate 30A in the sputtering process is changed to 50 seconds, 90 seconds, 195 seconds, 285 seconds, and 585 seconds. Note that the case where the FAB irradiation time in the sputtering process is set to 285 seconds corresponds to the above-mentioned Example 3.

From the table in Fig. 11, it can be seen that if the thickness of bonding layer 33 is 0.3 nm or more, the bonding strength is 1 J/m2 or ^more , and sufficient bonding strength can be obtained. In other words, in the composite substrate described in the above-mentioned Patent Document 1, a thickness of at least about ² nm is required for the bonding layer to obtain a bonding strength of 1 J/m2 or more, whereas in the composite substrate 110 to which the present invention is applied, if the thickness of bonding layer 33 is 0.3 nm or more, a bonding strength equal to or greater than that of the composite substrate described in Patent Document 1 can be obtained. This point is similar to that of the other composite substrates 100, 120, and 130.

From the viewpoint of shortening the manufacturing time in the sputtering process and miniaturizing the product, it is preferable to make the thickness of the bonding layer 33 as thin as possible, as long as sufficient bonding strength is obtained in the manufactured composite substrates 100 to 130. For example, if the maximum thickness of the bonding layer 33 is 3 nm, the above results indicate that the thickness of the bonding layer 33 in the composite substrates 100 to 130 can be set to 0.3 nm or more and 3 nm or less.

(Relationship between FAB irradiation time and bonding strength in activation process)
Among the manufacturing parameters described in Examples 1 and 2, the FAB irradiation time of the functional substrate 10 in the activation process was changed, and the other parameters were kept the same as in Examples 1 and 2. Using multiple composite substrates 100 each produced with these parameters, the relationship between the thickness of the bonding layer 33 in the support substrate 30 and the bonding strength was measured.

Figure 12 is a table showing the relationship between the FAB irradiation time of the functional substrate 10 and the semiconductor substrate 30A in the composite substrate 100 and the bonding strength. The table in Figure 12 shows the FAB irradiation time of the semiconductor substrate 30A combined in the activation process and the sputtering process, and the bonding strength of each composite substrate 100 produced when the FAB irradiation time of the functional substrate 10 and the semiconductor substrate 30A in the activation process is changed to 15 seconds, 30 seconds, 300 seconds, and 510 seconds, and the FAB irradiation time of the semiconductor substrate 30A in the sputtering process is fixed at 90 seconds. Note that the cases where the FAB irradiation time in the sputtering process is 15 seconds and 30 seconds correspond to the above-mentioned Example 1 and Example 2, respectively.

12, it can be seen that if the FAB irradiation time in the activation step is 300 seconds or less, the bonding strength is 1 J/ ^m2 or more, which is sufficient, while if the FAB irradiation time in the activation step exceeds 300 seconds, the bonding strength decreases. This is thought to be because the longer the FAB irradiation time of the functional substrate 10 in the activation step, the greater the surface roughness of the functional substrate 10 becomes, and if this surface roughness exceeds a certain level, it leads to a decrease in the bonding strength.

The values of the FAB irradiation time, thickness of the bonding layer 33, and bonding strength shown in the tables of Figures 11 and 12 are merely examples. These values can change depending on the type of functional material or semiconductor material used in the functional substrate 10 or semiconductor substrate 30A, the FAB voltage, current, rare gas flow rate, etc. Therefore, for example, instead of adjusting the FAB irradiation time, it is also possible to form the bonding layer 33 with the desired thickness by adjusting the FAB voltage, current, rare gas flow rate, etc.

The above-described embodiment of the present invention provides the following advantages:

(1) Composite substrates 100-130 have a functional substrate 10 made of a functional material, and a support substrate 30 made of a semiconductor material and bonded to the functional substrate 10 to support the functional substrate 10. The functional substrate 10 has a first layer (first functional layer 11 or first insulating layer 21) and a second layer (second functional layer 12 or second insulating layer 22) arranged closer to the support substrate 30 than the first layer and made of an amorphous body containing a rare gas. The support substrate 30 has a first support layer 31, a second support layer 32 arranged closer to the functional substrate 10 than the first support layer 31 and made of an amorphous body of a semiconductor material containing a rare gas, and a bonding layer 33 made of an amorphous body of a semiconductor material in contact with the functional substrate 10. In this way, it is possible to realize composite substrates 100-130 in which a functional substrate 10 and a support substrate 30 are bonded via a bonding layer 33, and which are capable of obtaining sufficient bonding strength even if the bonding layer 33 is thin.

(2) In the composite substrates 100, 120, the functional substrate 10 has a first functional layer 11 made of a crystalline functional material, and a second functional layer 12 made of an amorphous functional material and in contact with the bonding layer 33. In this configuration, the first layer is the first functional layer 11, and the second layer is the second functional layer 12. As a result, it is possible to realize the composite substrates 100, 120 that can obtain sufficient bonding strength even when the functional substrate 10 and the support substrate 30 are directly bonded without the insulating layer 20 between them.

(3) In the composite substrates 110 and 130, the functional substrate 10 is bonded to the support substrate 30 via an insulating layer 20 made of an insulating material, and the insulating layer 20 has a first insulating layer 21 made of an insulating material and a second insulating layer 22 made of an amorphous body of the insulating material and in contact with the bonding layer 33. In this configuration, the first layer is the first insulating layer 21, and the second layer is the second insulating layer 22. In this way, it is possible to realize the composite substrates 110 and 130 that can obtain sufficient bonding strength even when the functional substrate 10 and the support substrate 30 are bonded via the insulating layer 20.

(4) The thickness of the bonding layer 33 in the composite substrates 100 to 130 is preferably 0.3 nm or more and 3 nm or less. This allows shortening of the manufacturing time and miniaturization of the product while maintaining sufficient bonding strength.

(5) As shown in FIGS. 10(a) and 10(b), the bonding layer 33 contains a rare gas such as Ar, and the content of the rare gas in the bonding layer 33 is less than the content of the rare gas in the second support layer 32. The bonding layer 33 may also contain a metal element such as Al. In this way, the surface of the semiconductor substrate 30A is irradiated with FAB to bond the functional substrate 10 and the semiconductor substrate 30A using the sputtered film 30B formed on the surface of the functional substrate 10 as the bonding layer 33, and the composite substrates 100 to 130 can be produced using the semiconductor substrate 30A as the support substrate 30.

(6) As shown in FIG. 10(a), the first functional layer 11 contains a rare gas such as Ar or does not contain a rare gas. When the first functional layer 11 contains a rare gas, the content of the rare gas in the first functional layer 11 is less than the content of the rare gas in the second functional layer 12. The content of the rare gas in the second functional layer 12 is also less than the content of the rare gas in the second support layer 32. In this way, the surface of the functional substrate 10 before bonding is activated by irradiating the surface of the functional substrate 10 with FAB, and then the functional substrate 10 and the semiconductor substrate 30A are bonded to produce the composite substrates 100, 120.

(7) As shown in FIG. 10(b), the first insulating layer 21 contains a rare gas such as Ar or does not contain a rare gas. When the first insulating layer 21 contains a rare gas, the content of the rare gas in the first insulating layer 21 is less than the content of the rare gas in the second insulating layer 22. The content of the rare gas in the second insulating layer 22 is less than the content of the rare gas in the second support layer 32. In this way, the surface of the insulating layer 20 is activated by irradiating the surface of the functional substrate 10 before bonding on which the insulating layer 20 is formed with FAB, and then the insulating layer 20 and the semiconductor substrate 30A are bonded to produce the composite substrates 110 and 130.

(8) As shown in Figures 10(a) and (b), the first support layer 31 contains a rare gas such as Ar or does not contain a rare gas, and when the first support layer 31 contains a rare gas, the content of the rare gas in the first support layer 31 is lower than the content of the rare gas in the second support layer 32. In this way, the functional substrate 10 and the semiconductor substrate 30A can be bonded after FAB irradiation is performed on the surface of the semiconductor substrate 30A, and the composite substrates 100 to 130 can be produced using the semiconductor substrate 30A as the support substrate 30.

(9) The manufacturing method of the composite substrate 100, 120 including the functional substrate 10 made of a functional material and the support substrate 30 made of a semiconductor material and supporting the functional substrate 10 includes an activation step (FIG. 2(b)) in which the surface of the functional substrate 10 and the surface of the semiconductor substrate 30A made of a semiconductor material are irradiated with FAB so that at least a part of the irradiation time of each overlaps, a sputtering step (FIG. 2(c)) that is performed following the activation step, in which the irradiation of FAB to the surface of the functional substrate 10 is stopped and then the irradiation of FAB to the surface of the semiconductor substrate 30A is continued to sputter the semiconductor material onto the surface of the functional substrate 10, and a bonding step (FIG. 3(d)) in which the functional substrate 10 on which the semiconductor material has been sputtered by the sputtering step and the semiconductor substrate 30A are bonded to obtain a bonded body. In this way, the semiconductor substrate 30A and the sputtered film 30B are integrated to form the support substrate 30, and the composite substrate 100, 120 can be produced.

(10) A manufacturing method for composite substrates 110, 130 including a functional substrate 10 made of a functional material and a support substrate 30 made of a semiconductor material and supporting the functional substrate 10 includes an insulating layer formation process (FIG. 5(b)) for forming an insulating layer 20 made of an insulating material on the surface of the functional substrate 10, an activation process (FIG. 5(c)) for irradiating the surface of the insulating layer 20 and the surface of a semiconductor substrate 30A made of a semiconductor material with FAB so that at least a portion of the irradiation time of each overlaps, a sputtering process (FIG. 5(d)) that is performed following the activation process, in which after stopping the irradiation of the FAB on the surface of the insulating layer 20, the irradiation of the FAB on the surface of the semiconductor substrate 30A is continued to sputter a semiconductor material onto the surface of the insulating layer 20, and a bonding process (FIG. 6(e)) for bonding the functional substrate 10 and the semiconductor substrate 30A through the insulating layer 20 onto which the semiconductor material has been sputtered by the sputtering process to obtain a bonded body. In this way, the functional substrate 10 and the support substrate 30 can be bonded via the insulating layer 20 to produce the composite substrates 110, 130.

(11) In the sputtering process of FIG. 2(c) and FIG. 5(d), it is preferable to form the sputtered film 30B with a thickness of 0.3 nm or more and 3 nm or less. In this way, it is possible to produce composite substrates 100-130 that can shorten the manufacturing time and reduce the product size while maintaining sufficient bonding strength.

(12) The functional substrate 10 and the semiconductor substrate 30A may be placed in a vacuum chamber in which a first FAB gun and a second FAB gun are installed. In the activation process of FIG. 2(b) and FIG. 5(c), a rare gas such as Ar may be supplied to the first FAB gun and the second FAB gun, respectively, and the rare gas FAB may be irradiated from the first FAB gun to the surface of the functional substrate 10 or the insulating layer 20, and may be irradiated from the second FAB gun to the surface of the semiconductor substrate 30A. In addition, in the sputtering process of FIG. 2(c) and FIG. 5(d), the irradiation of the FAB from the first FAB gun to the surface of the functional substrate 10 or the insulating layer 20 may be stopped while the supply of the rare gas to the first FAB gun is continued. In this way, the activation process can be properly performed on the functional substrate 10 and the semiconductor substrate 30A, and the sputtering process can be properly performed on the semiconductor substrate 30A, thereby making it possible to produce the composite substrates 100-130.

In each embodiment of the present invention described above, the first FAB gun irradiates the surface of the functional substrate 10 or the insulating layer 20 with FAB, and the second FAB gun irradiates the surface of the semiconductor substrate 30A with FAB simultaneously. This makes it possible to prevent impurities such as an oxide film formed on the surface of the semiconductor substrate 30A from adhering to the surface of the functional substrate 10 or the insulating layer 20. However, the present invention is not limited to this. For example, a method may be adopted in which the first FAB gun first starts FAB irradiation on the functional substrate 10 side, and then the second FAB gun starts FAB irradiation on the semiconductor substrate 30A side with a delay of a predetermined time, and then the FAB irradiation on the functional substrate 10 side is stopped first. In this way, the same effect as described above can be obtained.

The present invention is not limited to the above embodiment, and can be implemented using any components without departing from the spirit of the invention.

The above embodiments and modifications are merely examples, and the present invention is not limited to these contents as long as the characteristics of the invention are not impaired. In addition, although various embodiments and modifications have been described above, the present invention is not limited to these contents. Other aspects that are conceivable within the scope of the technical concept of the present invention are also included within the scope of the present invention.

10: Functional substrate 11: First functional layer 12: Second functional layer 20: Insulating layer 21: First insulating layer 22: Second insulating layer 30: Support substrate 30A: Semiconductor substrate 30B: Sputtered film 31: First supporting layer 32: Second supporting layer 33: Bonding layer 40: Bonding interface 50: Ridge portion 100, 110, 120, 130: Composite substrate

Claims (17)

A functional substrate made of a functional material;
a support substrate made of a semiconductor material and bonded to the functional substrate to support the functional substrate;
the functional substrate includes a first functional layer made of a crystal of the functional material , and a second functional layer arranged closer to the support substrate than the first functional layer and made of an amorphous body of the functional material containing a rare gas;
the support substrate includes a first support layer, a second support layer disposed closer to the functional substrate than the first support layer and made of an amorphous body of the semiconductor material containing the rare gas, and a bonding layer in contact with the functional substrate and made of an amorphous body of the semiconductor material;
the bonding layer contains the rare gas;
A composite substrate, wherein the bonding layer has a lower content of the rare gas than the second support layer . A functional substrate made of a functional material;
a support substrate made of a semiconductor material and bonded to the functional substrate to support the functional substrate;
the functional substrate is bonded to the support substrate via an insulating layer made of an insulating material;
the support substrate includes a first support layer, a second support layer that is disposed closer to the functional substrate than the first support layer and is made of an amorphous body of the semiconductor material containing a rare gas, and a bonding layer that is in contact with the insulating layer and is made of an amorphous body of the semiconductor material;
the insulating layer includes a first insulating layer made of the insulating material, and a second insulating layer made of an amorphous body of the insulating material and in contact with the bonding layer;
the bonding layer contains the rare gas;
A composite substrate, wherein the bonding layer has a lower content of the rare gas than the second support layer . The composite substrate according to claim 1 or 2 ,
The thickness of the bonding layer is 0.3 nm or more and 3 nm or less. The composite substrate according to claim 1 or 2 ,
The bonding layer comprises a metal element. 2. The composite substrate according to claim 1 ,
the first functional layer contains the rare gas or does not contain the rare gas;
A composite substrate, wherein when the first functional layer contains the rare gas, the content of the rare gas in the first functional layer is lower than the content of the rare gas in the second functional layer. The composite substrate according to claim 5 ,
A composite substrate, wherein the content of the rare gas in the second functional layer is lower than the content of the rare gas in the second support layer. The composite substrate according to claim 2 ,
the first insulating layer contains the rare gas or does not contain the rare gas;
A composite substrate, wherein when the first insulating layer contains the rare gas, the content of the rare gas in the first insulating layer is lower than the content of the rare gas in the second insulating layer. The composite substrate according to claim 7 ,
A composite substrate, wherein the content of the rare gas in the second insulating layer is less than the content of the rare gas in the second support layer. The composite substrate according to claim 1 or 2 ,
the first support layer contains the rare gas or does not contain the rare gas;
A composite substrate, wherein when the first support layer contains the rare gas, the content of the rare gas in the first support layer is lower than the content of the rare gas in the second support layer. A method for manufacturing a composite substrate including a functional substrate made of a functional material and a support substrate made of a semiconductor material and supporting the functional substrate, comprising:
an activation step of irradiating a surface of the functional substrate and a surface of a semiconductor substrate made of the semiconductor material with a fast atomic beam so that the irradiation times of the fast atomic beams overlap at least partially;
a sputtering step, which is carried out following the activation step, in which, after stopping the irradiation of the surface of the functional substrate with the fast atomic beam, the irradiation of the surface of the semiconductor substrate with the fast atomic beam is continued to sputter the semiconductor material onto the surface of the functional substrate;
a bonding step of bonding the functional substrate on which the semiconductor material has been sputtered in the sputtering step to the semiconductor substrate to obtain a bonded body. A method for manufacturing a composite substrate including a functional substrate made of a functional material and a support substrate made of a semiconductor material and supporting the functional substrate, comprising:
an insulating layer forming step of forming an insulating layer made of an insulating material on a surface of the functional substrate;
an activation step of irradiating a surface of the insulating layer and a surface of a semiconductor substrate made of the semiconductor material with a fast atomic beam so that the irradiation times of the fast atomic beams overlap at least partially;
a sputtering step, which is carried out following the activation step, in which, after stopping the irradiation of the surface of the insulating layer with the fast atomic beam, the irradiation of the surface of the semiconductor substrate with the fast atomic beam is continued to sputter the semiconductor material onto the surface of the insulating layer;
a bonding step of bonding the functional substrate and the semiconductor substrate via the insulating layer on which the semiconductor material is sputtered in the sputtering step to obtain a bonded body. The method for producing a composite substrate according to claim 10 ,
In the sputtering step, a sputtered film made of an amorphous body of the sputtered semiconductor material is formed on the surface of the functional substrate to a thickness of 0.3 nm or more and 3 nm or less. The method for producing a composite substrate according to claim 11 ,
In the sputtering step , a sputtered film made of an amorphous body of the sputtered semiconductor material is formed on the surface of the insulating layer to a thickness of 0.3 nm or more and 3 nm or less. The method for producing a composite substrate according to claim 10 ,
the functional substrate and the semiconductor substrate are placed in a vacuum chamber in which a first fast atom beam gun and a second fast atom beam gun are installed;
In the activation step, a rare gas is supplied to each of the first high-speed atom beam gun and the second high-speed atom beam gun, and the high-speed atomic beam of the rare gas is irradiated from the first high-speed atom beam gun onto the surface of the functional substrate , and is irradiated from the second high-speed atom beam gun onto the surface of the semiconductor substrate;
a first high-speed atomic beam gun that is adapted to supply a rare gas to the first high-speed atomic beam gun and a second high-speed atomic beam gun that is adapted to supply a rare gas to the first high-speed atomic beam gun ; The method for producing a composite substrate according to claim 11 ,
the functional substrate and the semiconductor substrate are placed in a vacuum chamber in which a first fast atom beam gun and a second fast atom beam gun are installed;
In the activation step, a rare gas is supplied to each of the first high-speed atom beam gun and the second high-speed atom beam gun, and the high-speed atom beam generated by the rare gas is irradiated onto the surface of the insulating layer from the first high-speed atom beam gun and onto the surface of the semiconductor substrate from the second high-speed atom beam gun;
a first high-speed atom beam gun that is adapted to supply a rare gas to the first high-speed atom beam gun and a second high-speed atom beam gun that is adapted to supply a rare gas to the first high-speed atom beam gun; The method for producing a composite substrate according to claim 14 ,
a first high-speed atomic beam gun for irradiating a surface of the functional substrate with the high-speed atomic beam, and a second high-speed atomic beam gun for irradiating a surface of the semiconductor substrate with the high-speed atomic beam, the second high-speed atomic beam gun for irradiating a surface of the functional substrate with the high-speed atomic beam, the second high-speed atomic beam gun for irradiating a surface of the semiconductor substrate with the high-speed atomic beam, The method for producing a composite substrate according to claim 15,
a first high-speed atomic beam gun for irradiating a surface of the insulating layer with the high-speed atomic beam and a second high-speed atomic beam gun for irradiating a surface of the semiconductor substrate with the high-speed atomic beam, the second high-speed atomic beam gun being capable of irradiating the surface of the insulating layer with the high-speed atomic beam.

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