Semiconductor support structure, method for manufacturing semiconductor support structure, and method for manufacturing semiconductor device

Abstract

This method for manufacturing a semiconductor support structure (10) comprises: a step for obtaining a plurality of semiconductor thin films (110) that are formed of semiconductor thin films (110) crystal-grown on a growth substrate (101) and are not bonded to the growth substrate (101); a step for bonding the plurality of semiconductor thin films (110) to an intermediate sacrificial layer (121) formed on an intermediate substrate (120) different from the growth substrate (101); and a step for forming a plurality of support layers (122) for supporting the plurality of semiconductor thin films (110) by partially removing the intermediate sacrificial layer (121), and forming a gap (123) between the intermediate substrate (120) and a first surface of each semiconductor thin film (110) facing the intermediate substrate (120).

Description

Semiconductor support structure, method for manufacturing a semiconductor support structure, and method for manufacturing a semiconductor device

[0001] This disclosure relates to a semiconductor support structure, a method for manufacturing a semiconductor support structure, and a method for manufacturing a semiconductor device.

[0002] Conventionally, a technique has been known in which a semiconductor thin film (functional layer) and a support layer are formed on a growth substrate, the support layer is broken to selectively peel the semiconductor thin film from the growth substrate, and the peeled semiconductor thin film is transferred to another substrate (for example, Patent Document 1).

[0003] Japanese Patent Publication No. 2024-63293 (see Figures 5 and 19)

[0004] However, conventional techniques require the formation of a support layer on the growth substrate, and also the removal of any remaining support layer fragments on the growth substrate after the semiconductor thin film transfer. Therefore, it is difficult to efficiently perform the transfer process, which selectively transfers the semiconductor thin film from the growth substrate to another substrate.

[0005] This disclosure aims to enable efficient transfer when selectively transferring a semiconductor thin film to another substrate.

[0006] The method for manufacturing a semiconductor support structure according to the present disclosure includes the steps of: obtaining a plurality of semiconductor thin films formed from a semiconductor layer crystallized on a growth substrate and not bonded to the growth substrate; bonding the plurality of semiconductor thin films to a sacrificial layer formed on an intermediate substrate different from the growth substrate; and forming a plurality of support layers that support the plurality of semiconductor thin films by partially removing the sacrificial layer, thereby forming a gap between a first surface of each semiconductor thin film facing the intermediate substrate and the intermediate substrate.

[0007] The method for manufacturing a semiconductor device according to the present disclosure comprises the steps of: selectively separating at least one semiconductor thin film from the support layer among the plurality of semiconductor thin films of the semiconductor support structure manufactured by the method for manufacturing the semiconductor support structure described above; and bonding the at least one semiconductor thin film to a device substrate different from the growth substrate and the intermediate substrate.

[0008] The semiconductor support structure of this disclosure comprises a substrate, a plurality of support layers formed on the substrate, and a plurality of semiconductor thin films formed by crystal growth on a growth substrate different from the substrate and supported by the plurality of support layers, wherein a void is formed between the first surface of each semiconductor thin film facing the substrate and the substrate.

[0009] According to this disclosure, multiple semiconductor thin films are bonded to multiple support layers formed on an intermediate substrate, and voids are formed between each semiconductor thin film and the intermediate substrate, so that each semiconductor thin film can be easily separated from the support layer. This allows for efficient transfer when selectively transferring semiconductor thin films to another substrate.

[0010] This is a flowchart showing a method for manufacturing a semiconductor device according to Embodiment 1. This is a cross-sectional view showing the process of forming each semiconductor layer, including a semiconductor thin film, on a growth substrate in Embodiment 1. (A) and (B) are cross-sectional and plan views showing the process of patterning a semiconductor thin film in Embodiment 1, and Figure 3(C) is a cross-sectional view showing an enlarged view of the portion enclosed by the dashed line P1 in Figure 3(A). This is a cross-sectional view showing the process of forming a protective film covering the semiconductor thin film in Embodiment 1. This is a cross-sectional view showing the process of attaching the semiconductor thin film to a first transfer substrate in Embodiment 1. This is a cross-sectional view showing the process of removing the growth substrate and separating the semiconductor thin film in Embodiment 1. This is a cross-sectional view showing the process of removing the stop layer in Embodiment 1. This is a cross-sectional view showing the process of transferring the semiconductor thin film to an intermediate substrate in Embodiment 1. This is a cross-sectional view showing the state after removing the first transfer substrate in Embodiment 1. This is a cross-sectional view showing the process of partially removing the intermediate sacrificial layer of the intermediate substrate in Embodiment 1. (A) and (B) are cross-sectional views showing the process of selectively separating the semiconductor thin film from the intermediate substrate in Embodiment 1. Figures (A) and (B) are cross-sectional views showing the steps of bonding a semiconductor thin film to a device substrate and forming electrodes in Embodiment 1. This is a flowchart showing the method for manufacturing a semiconductor device in Embodiment 2. This is a cross-sectional view showing the step of forming each semiconductor layer, including a semiconductor thin film, on a growth substrate in Embodiment 2. Figures (A) and (B) are cross-sectional and plan views showing the step of patterning a semiconductor thin film in Embodiment 2, and Figure 15(C) is a cross-sectional view showing an enlarged view of the portion enclosed by the dashed line P1 in Figure 15(A). This is a cross-sectional view showing the step of forming a protective film covering the semiconductor thin film in Embodiment 2. This is a cross-sectional view showing the step of attaching a semiconductor thin film to a first transfer substrate in Embodiment 2. This is a cross-sectional view showing the step of removing the growth substrate and separating the semiconductor thin film in Embodiment 2. Figures (A), (B), and (C) are cross-sectional views showing the step of removing the first stop layer, the second stop layer, and the third stop layer in Embodiment 2. This is a flowchart showing the method for manufacturing a semiconductor device in Embodiment 3. This is a cross-sectional view showing the step of forming each semiconductor layer, including a semiconductor thin film, on a growth substrate in Embodiment 3.Figures (A) and (B) are cross-sectional and plan views showing the process of patterning a semiconductor thin film in Embodiment 3, and Figure 22(C) is a cross-sectional view showing an enlarged view of the portion enclosed by the dashed line P1 in Figure 22(A). Figure 3 is a cross-sectional view showing the process of forming a protective film covering the semiconductor thin film. Figure 3 is a cross-sectional view showing the process of attaching the semiconductor thin film to the first transfer substrate. Figure 3 is a cross-sectional view showing the process of removing the growth substrate and separating the semiconductor thin film. Figure 3 is a cross-sectional view showing the process of removing the stop layer. Figure 3 is a cross-sectional view showing the process of forming a metal film on the lower surface of the semiconductor thin film. Figure 3 is a cross-sectional view showing the process of transferring the semiconductor thin film to an intermediate substrate. Figure 3 is a cross-sectional view showing the state after the first transfer substrate has been removed. Figure 3 is a cross-sectional view showing the process of partially removing the intermediate sacrificial layer of the intermediate substrate. Figures (A) and (B) are cross-sectional views showing the process of selectively separating the semiconductor thin film from the intermediate substrate in Embodiment 3. Figures (A) and (B) are cross-sectional views showing the steps of bonding a semiconductor thin film to a device substrate and forming electrodes on the device substrate in Embodiment 3. This is a flowchart showing the method for manufacturing a semiconductor device in Embodiment 4. This is a cross-sectional view showing the steps of forming each semiconductor layer, including a semiconductor thin film, on a growth substrate in Embodiment 4. Figures (A) and (B) are cross-sectional and plan views showing the steps of patterning a semiconductor thin film in Embodiment 4, and Figure 35(C) is a cross-sectional view showing an enlarged view of the portion enclosed by the dashed line P1 in Figure 35(A). This is a cross-sectional view showing the steps of forming a protective film to cover the semiconductor thin film in Embodiment 4. This is a cross-sectional view showing the steps of attaching a semiconductor thin film to a first transfer substrate in Embodiment 4. This is a cross-sectional view showing the steps of removing the sacrificial layer to separate the semiconductor thin film in Embodiment 4. This is a cross-sectional view showing the steps of removing the stop layer in Embodiment 4. Figures (A) and (B) are cross-sectional and plan views showing a modified example in which a semiconductor thin film has been transferred to an intermediate substrate. Figures (A) and (B) are cross-sectional views showing a modified example in which the intermediate sacrificial layer of the intermediate substrate is partially removed. This is a flowchart showing the method for manufacturing a semiconductor device according to Embodiment 5.This is a cross-sectional view showing the process of forming each semiconductor layer, including a semiconductor thin film, on a growth substrate in Embodiment 5. (A) and (B) are a cross-sectional view and a plan view showing the process of patterning the semiconductor thin film in Embodiment 5. This is a cross-sectional view showing the process of forming a protective film covering the semiconductor thin film in Embodiment 5. This is a cross-sectional view showing the process of attaching the semiconductor thin film to a first transfer substrate in Embodiment 5. This is a cross-sectional view showing the process of removing the sacrificial layer to separate the semiconductor thin film in Embodiment 5. This is a cross-sectional view showing the process of removing the stop layer in Embodiment 5. This is a flowchart showing the method for manufacturing a semiconductor device in Embodiment 6. This is a cross-sectional view showing the process of forming each semiconductor layer, including a semiconductor thin film, on a growth substrate in Embodiment 6. (A) and (B) are a cross-sectional view and a plan view showing the process of patterning the semiconductor thin film in Embodiment 6. This is a cross-sectional view showing the process of forming a protective film covering the semiconductor thin film in Embodiment 6. This is a cross-sectional view showing the process of attaching the semiconductor thin film to a first transfer substrate in Embodiment 6. This is a cross-sectional view showing the process of removing the sacrificial layer to separate the semiconductor thin film in Embodiment 6. This is a cross-sectional view showing the process of removing the stop layer in Embodiment 6. This is a flowchart showing the method for manufacturing a semiconductor device in Embodiment 7. This is a cross-sectional view showing the process of forming each semiconductor layer, including a semiconductor thin film, on a growth substrate in Embodiment 7. (A) and (B) are a cross-sectional view and a plan view showing the process of patterning a semiconductor thin film in Embodiment 7. This is a cross-sectional view showing the process of forming a protective film covering the semiconductor thin film in Embodiment 7. This is a cross-sectional view showing the process of attaching the semiconductor thin film to a first transfer substrate in Embodiment 7. This is a cross-sectional view showing the process of removing the sacrificial layer to separate the semiconductor thin film in Embodiment 7. This is a cross-sectional view showing the process of removing the first stop layer in Embodiment 7. This is a cross-sectional view showing the process of removing the second stop layer in Embodiment 7. This is a flowchart showing the method for manufacturing a semiconductor device according to Embodiment 8. This is a cross-sectional view showing the process of forming each semiconductor layer, including a semiconductor thin film, on a growth substrate in Embodiment 8. (A) and (B) are a cross-sectional view and a plan view showing the process of patterning a semiconductor thin film in Embodiment 8.This is a cross-sectional view showing the step of forming a protective film covering a semiconductor thin film in Embodiment 8. This is a cross-sectional view showing the step of attaching a semiconductor thin film to a first transfer substrate in Embodiment 8. This is a cross-sectional view showing the step of removing a sacrificial layer to separate the semiconductor thin film in Embodiment 8. (A) and (B) are cross-sectional views showing the steps of removing a first stop layer and removing a second stop layer in Embodiment 8. This is a flowchart showing the method for manufacturing a semiconductor device according to Embodiment 9. This is a cross-sectional view showing the step of forming each semiconductor layer, including a semiconductor thin film, on a growth substrate in Embodiment 9. (A) and (B) are a cross-sectional view and a plan view showing the step of patterning a semiconductor thin film in Embodiment 9. This is a cross-sectional view showing the step of forming a protective film covering a semiconductor thin film in Embodiment 9. This is a cross-sectional view showing the step of attaching a semiconductor thin film to a first transfer substrate in Embodiment 9. This is a cross-sectional view showing the step of removing a sacrificial layer to separate the semiconductor thin film in Embodiment 9. This is a cross-sectional view showing the step of removing a stop layer in Embodiment 9. This is a cross-sectional view showing the step of forming each semiconductor layer, including a semiconductor thin film, on a growth substrate in Embodiment 10. (A) and (B) are cross-sectional and plan views showing the process of patterning a semiconductor thin film in Embodiment 10. This is a cross-sectional view showing the process of forming a protective film covering the semiconductor thin film in Embodiment 10. This is a cross-sectional view showing the process of attaching the semiconductor thin film to the first transfer substrate in Embodiment 10. This is a cross-sectional view showing the process of removing the growth substrate and separating the semiconductor thin film in Embodiment 10. This is a cross-sectional view showing the process of forming each semiconductor layer, including the semiconductor thin film, on the growth substrate in Embodiment 11. (A) and (B) are cross-sectional and plan views showing the process of patterning a semiconductor thin film in Embodiment 11. This is a cross-sectional view showing the process of forming a protective film covering the semiconductor thin film in Embodiment 11. This is a cross-sectional view showing the process of attaching the semiconductor thin film to the first transfer substrate in Embodiment 11. This is a cross-sectional view showing the process of removing the growth substrate and separating the semiconductor thin film in Embodiment 11. This is a cross-sectional view showing the process of removing the first stop layer in Embodiment 11. This is a cross-sectional view showing the process of removing the second stop layer in Embodiment 11.This is a flowchart illustrating a method for manufacturing a semiconductor device according to Embodiment 12. This is a cross-sectional view showing the process of forming each semiconductor layer, including a semiconductor thin film, on a growth substrate in Embodiment 12. This is a cross-sectional view showing the process of attaching the semiconductor thin film to a first transfer substrate in Embodiment 12. This is a cross-sectional view showing the process of removing the growth substrate and separating the semiconductor thin film in Embodiment 12. (A) and (B) are a cross-sectional view and a plan view showing the process of patterning the semiconductor thin film in Embodiment 12. This is a cross-sectional view showing the process of forming a protective film covering the semiconductor thin film in Embodiment 12. This is a cross-sectional view showing the process of removing a part of the protective film in Embodiment 12. This is a cross-sectional view showing the process of removing the stop layer in Embodiment 12. This is a cross-sectional view showing the process of removing the protective film in Embodiment 12. This is a cross-sectional view showing the process of forming each semiconductor layer, including a semiconductor thin film, on a growth substrate in Embodiment 13. This is a cross-sectional view showing the process of attaching the semiconductor thin film to a first transfer substrate in Embodiment 13. This is a cross-sectional view showing the process of removing the growth substrate and separating the semiconductor thin film in Embodiment 13. (A) and (B) are a cross-sectional view and a plan view showing the process of patterning the semiconductor thin film in Embodiment 13. This is a cross-sectional view showing the process of forming a protective film covering a semiconductor thin film in Embodiment 13. This is a cross-sectional view showing the process of removing a part of the protective film in Embodiment 13. This is a cross-sectional view showing the process of removing the first stop layer in Embodiment 13. This is a cross-sectional view showing the process of removing the second stop layer in Embodiment 13. This is a cross-sectional view showing the process of removing the third stop layer in Embodiment 13. This is a cross-sectional view showing the process of removing the protective film in Embodiment 13. This is a cross-sectional view showing the process of forming each semiconductor layer, including a semiconductor thin film, on a growth substrate in Embodiment 14. This is a cross-sectional view showing the process of attaching a semiconductor thin film to a first transfer substrate in Embodiment 14. This is a cross-sectional view showing the process of removing the growth substrate and separating the semiconductor thin film in Embodiment 14. (A) and (B) are a cross-sectional view and a plan view showing the process of patterning a semiconductor thin film in Embodiment 14.This is a cross-sectional view showing the process of forming each semiconductor layer, including a semiconductor thin film, on a growth substrate in Embodiment 15. This is a cross-sectional view showing the process of attaching the semiconductor thin film to a first transfer substrate in Embodiment 15. This is a cross-sectional view showing the process of removing the growth substrate and separating the semiconductor thin film in Embodiment 15. (A) and (B) are a cross-sectional view and a plan view showing the process of patterning the semiconductor thin film in Embodiment 15. This is a cross-sectional view showing the process of forming a protective film that covers the semiconductor thin film in Embodiment 15. This is a cross-sectional view showing the process of removing a part of the protective film in Embodiment 15. This is a cross-sectional view showing the process of removing the first stop layer in Embodiment 15. This is a cross-sectional view showing the process of removing the second stop layer in Embodiment 15. This is a cross-sectional view showing the process of removing the protective film in Embodiment 15.

[0011] The semiconductor support structure, the method for manufacturing the semiconductor support structure, and the method for manufacturing the semiconductor device in the embodiments will be described below with reference to the drawings. The following embodiments are merely examples, and various modifications are possible within the scope of this disclosure.

[0012] <Embodiment 1> <Method for Manufacturing Semiconductor Devices> The semiconductor device of Embodiment 1 is, for example, a light-emitting element such as an LED (light-emitting diode) or a surface-emitting laser, or a light-receiving element such as a photodiode. The light-emitting element and the light-receiving element are collectively referred to as a photoelectric conversion element.

[0013] When the semiconductor device is a light-emitting element, it can be used in display devices such as LED displays. When the semiconductor device is a light-receiving element, it can be used in optical sensors, photodetectors, image sensors, or light-receiving parts for optical communication.

[0014] Figure 1 is a flowchart showing the manufacturing method of the semiconductor device 1 according to Embodiment 1. Figure 2 is a cross-sectional view showing the process of forming each semiconductor layer, including the semiconductor thin film 110, on the growth substrate 101.

[0015] In step S101 (Figure 1), as shown in Figure 2, a buffer layer 102, a stop layer 103 as an etching stop layer, a lower cladding layer 104, an active layer 105, an upper cladding layer 106, and a contact layer 107 are sequentially formed on the growth substrate 101 by epitaxial growth. The substrate 101 with each of the layers 102 to 107 formed on it is also called a laminated substrate 100.

[0016] Of these, the lower cladding layer 104, the active layer 105, the upper cladding layer 106, and the contact layer 107 constitute the semiconductor thin film 110. The semiconductor thin film 110 is also referred to as the semiconductor crystal layer or the functional layer. Furthermore, the semiconductor thin film 110 before patterning (Figures 3(A) to (C)), which will be described later, is also referred to as the semiconductor layer. The stop layer 103 is also referred to as the predetermined layer.

[0017] The growth substrate 101 is a substrate formed of InP (indium phosphide), i.e., an InP substrate, and is also referred to as the first substrate. The growth substrate 101 is a substrate on which an epitaxial layer is grown on its upper surface.

[0018] The buffer layer 102 is formed of InP. The thickness of the buffer layer 102 is, for example, several hundred nm. The buffer layer 102 is an intermediate layer that mitigates crystal defects in the growth substrate 101 and improves the crystallinity of the semiconductor thin film 110. If the crystallinity of the growth substrate 101 is good, or if the crystallinity of the semiconductor thin film 110 is not a concern, the thickness of the buffer layer 102 may be 100 nm or less, or the buffer layer 102 may be omitted.

[0019] The stop layer 103 is formed of i-InGaAs (i-type indium gallium arsenide). The thickness of the stop layer 103 is such that etching can be stopped in the etching steps S102 and S105 described later (i.e., a thickness that does not allow etching to penetrate), for example, several hundred nm to 1 μm.

[0020] The lower cladding layer 104 is made of n-InP (n-type indium phosphide). The active layer 105 is made of i-InGaAs (i-type indium gallium arsenide). The upper cladding layer 106 is made of p-InP (p-type indium phosphide). The contact layer 107 is made of p-InGaAs (p-type indium gallium arsenide).

[0021] The thickness of the lower cladding layer 104, the active layer 105, the upper cladding layer 106, and the contact layer 107 is several hundred nm to 1 μm. The active layer (also called the photoelectric conversion layer) 105 is a light-absorbing layer in this case, but it may also be a light-emitting layer. The contact layer 107 is a layer on which electrodes or the like are formed on its upper surface.

[0022] Figures 3(A) and 3(B) are a cross-sectional view and a plan view showing the process of patterning the semiconductor thin film 110. Figure 3(C) is an enlarged view of the area enclosed by the dashed line P1 in Figure 3(A).

[0023] As shown in Figures 3(A) and 3(B), in step S102 (Figure 1), the semiconductor thin film 110 is etched along a predetermined separation region to form a grid-like groove G1. Figures 3(A) and 3(B) show the portion of the semiconductor thin film 110 that has been separated into 4 rows and 4 columns (16 regions).

[0024] As shown in Figure 3(C), the semiconductor thin film 110 is patterned by etching from the topmost contact layer 107 to the stop layer 103. Dry etching is used as the etching method.

[0025] The etching direction for dry etching is vertical, that is, perpendicular to the upper surface of the growth substrate 101 (orthogonal to the surface orientation 010 or 001). The thickness of the stop layer 103 is set to a thickness such that etching does not reach the growth substrate 101 and the buffer layer 102.

[0026] Note that the lower clad layer 104 may be patterned by wet etching. In this case, an etchant having a large selection ratio between InP (lower clad layer 104) and InGaAs (stop layer 103) is used. More specifically, an etchant in which the etching rate of InP is higher than the etching rate of InGaAs is used.

[0027] FIG. 4 is a cross-sectional view showing the step of forming a protective film 111 covering the semiconductor thin film 110. In step S103 (FIG. 1), as shown in FIG. 4, a protective film 111 is formed to cover the semiconductor thin film 110. The protective film 111 covers the upper surface and the side surface of the semiconductor thin film 110, and is for protecting the semiconductor thin film 110 from damage by an etchant used in the removal process of the growth substrate 101 described later.

[0028] The protective film 111 is formed of an inorganic material or an organic material. As the inorganic material, for example, Al ２ O ３ (alumina), Si ３ N ４ (silicon nitride) or SiO ２ (silicon oxide) can be used. As the organic material, for example, a novolak-based photoresist, an epoxy-based photoresist, or a rubber-based photoresist can be used. Note that the protective film 111 is not limited to the materials described above as long as it can protect the semiconductor thin film 110 from the etchant used in the removal process of the growth substrate 101.

[0029] When the protective film 111 is Al ２ O ３ , Si ３ N ４ or SiO ２ , it can be formed by CVD (chemical vapor deposition) or sputtering, and the thickness is, for example, several tens of nm to less than 10 μm. When the protective film 111 is a photoresist, it can be formed by coating, and the thickness is, for example, several μm to several tens of μm.

[0030] FIG. 5 is a cross-sectional view showing the step of attaching the semiconductor thin film 110 to the first transfer substrate 112. In step S104 (FIG. 1), as shown in FIG. 5, the semiconductor thin film 110 is attached to the first transfer substrate 112.

[0031] The first transfer substrate 112 is formed of, for example, Si (silicon), glass, or quartz. An adhesive layer 113 is formed on the lower surface of the first transfer substrate 112. The adhesive layer 113 is formed of an adhesive material (for example, an adhesive sheet) whose adhesiveness changes by heat or light.

[0032] By attaching the protective film 111 on the semiconductor thin film 110 to the adhesive layer 113 of the first transfer substrate 112, the semiconductor thin film 110 is held by the first transfer substrate 112.

[0033] FIG. 6 is a cross-sectional view showing the step of separating the semiconductor thin film 110 by removing the growth substrate 101. In step S105 (FIG. 1), as shown in FIG. 6, the growth substrate 101 and the buffer layer 102 are removed by wet etching from the lower surface (the surface opposite to the semiconductor thin film 110), thereby separating the semiconductor thin film 110.

[0034] As the etchant, one having a large selection ratio between InP (growth substrate 101 and buffer layer 102) and InGaAs (stop layer 103) is used. More specifically, an etchant in which the etching rate of InP is higher than the etching rate of InGaAs is used. Also, it is necessary that the etchant does not etch the protective film 111, the first transfer substrate 112, and the adhesive layer 113. As such an etchant, hydrochloric acid, a mixed solution of hydrochloric acid and phosphoric acid, or a mixed solution of hydrochloric acid and nitric acid, etc. can be used.

[0035] Thereby, the etching can be stopped at the stop layer 103. When the growth substrate 101 and the buffer layer 102 are completely removed, the semiconductor thin film 110 is separated from them. During the wet etching, the semiconductor thin film 110 is held by the first transfer substrate 112.

[0036] Figure 7 is a cross-sectional view showing the process of removing the stop layer 103. In step S106 (Figure 1), the stop layer 103 is removed by wet etching.

[0037] As the etchant, one with a high selectivity ratio between InGaAs (stop layer 103) and InP (lower cladding layer 104) is used. Specifically, an etchant with a higher etching rate for InGaAs than for InP is used. For example, phosphoric acid, or a mixture of phosphoric acid and hydrogen peroxide, can be used.

[0038] Removing the stop layer 103 exposes the underside of the semiconductor thin film 110 (more specifically, the underside of the lower cladding layer 104). The underside of the semiconductor thin film 110 can generally maintain the smoothness it had when epitaxially grown on the growth substrate 101.

[0039] Figure 8 is a cross-sectional view showing the process of bonding (transferring) the semiconductor thin film 110 to the intermediate substrate 120. In step S107 (Figure 1), as shown in Figure 8, the semiconductor thin film 110 held on the first transfer substrate 112 is bonded to the intermediate substrate 120.

[0040] The intermediate substrate 120 is, for example, Si, glass, or sapphire (Al ２ O ３ ) is formed. An intermediate sacrificial layer 121 is formed on the upper surface of the intermediate substrate 120 as a sacrificial layer. The intermediate sacrificial layer 121 is an organic material such as polyimide or epoxy resin, or SiO ２ Al ２ O ３ Alternatively, it may be formed from inorganic materials such as metal.

[0041] If the intermediate sacrificial layer 121 is polyimide or epoxy resin, it can be formed by coating. ２ or Al ２ O ３ In this case, it can be formed by CVD or sputtering. In either case, the thickness of the intermediate sacrificial layer 121 is several nanometers to several tens of micrometers.

[0042] The semiconductor thin film 110 (more specifically, the lower cladding layer 104) is bonded to the intermediate sacrificial layer 121 of the intermediate substrate 120. At this time, by not performing heat treatment after bonding, the semiconductor thin film 110 and the intermediate sacrificial layer 121 are bonded by weak intermolecular forces.

[0043] Figure 9 is a cross-sectional view showing the process of removing the first transfer substrate 112. In step S108 (Figure 1), as shown in Figure 9, the first transfer substrate 112 is removed from the semiconductor thin film 110 bonded to the intermediate substrate 120.

[0044] By applying heat or light to the adhesive layer 113 of the first transfer substrate 112, the adhesiveness of the adhesive layer 113 is reduced, allowing the first transfer substrate 112 to be peeled off from the upper surface of the semiconductor thin film 110.

[0045] Furthermore, the protective film 111 covering the semiconductor thin film 110 is removed. ２ In this case, it can be removed by wet etching using hydrofluoric acid as the etchant. If the protective film 111 is Al ２ O ３ In this case, it can be removed by wet etching using phosphoric acid or hydrofluoric acid as the etchant. If the protective film 111 is an organic material, O ２ It can be removed by dry etching using plasma.

[0046] Figure 10 is a cross-sectional view showing the process of partially removing the intermediate sacrificial layer 121 of the intermediate substrate 120 by etching. As shown in Figure 10, in step S109 (Figure 1), the intermediate sacrificial layer 121 of the intermediate substrate 120 is partially removed by etching.

[0047] As for the etching method, if the intermediate sacrificial layer 121 is polyimide or epoxy resin, ２ Plasma-based dry etching is performed. The intermediate sacrificial layer 121 is SiO ２ In this case, wet etching is performed using hydrofluoric acid as the etchant, and Al ２ O ３ In this case, wet etching is performed using phosphoric acid or hydrofluoric acid as the etchant.

[0048] In both dry etching and wet etching, the etching conditions are set so that etching proceeds in a plane parallel to the upper surface of the intermediate substrate 120 until the intermediate sacrificial layer 121 is retracted inward from the outer periphery of each semiconductor thin film 110.

[0049] In dry etching, the potential difference accelerates ions toward the intermediate substrate 120, resulting in anisotropic etching with a fast etching rate in the vertical direction (perpendicular to the upper surface of the intermediate substrate 120). However, by adjusting the bias voltage, etching can also be advanced in the lateral direction (parallel to the upper surface of the intermediate substrate 120).

[0050] The portion of the intermediate sacrificial layer 121 that is not removed by etching, that is, the portion located beneath each semiconductor thin film 110, is referred to as the support layer (support) 122. On the intermediate substrate 120, the lower surface of each semiconductor thin film 110 is supported by the support layer 122. In addition, a gap 123 is formed between the lower surface of each semiconductor thin film 110 and the intermediate substrate 120.

[0051] By forming a gap 123 between the lower surface of the semiconductor thin film 110 and the intermediate substrate 120, the bonding force between the semiconductor thin film 110 and the support layer 122 is weakened, making separation, as described later, easier. The lower surface of the semiconductor thin film 110 (i.e., the surface facing the intermediate substrate 120) is also referred to as the first surface.

[0052] In this way, a semiconductor support structure 10 is obtained in which the semiconductor thin films 110 are supported on each support layer 122 on the intermediate substrate 120, and a gap 123 is formed between the lower surface of each semiconductor thin film 110 and the intermediate substrate 120. Each support layer 122 is joined to the center of the lower surface of the semiconductor thin film 110. Steps S101 to S109 shown in Figure 1 correspond to the manufacturing method of the semiconductor support structure 10. Steps S101 to S105 correspond to the process of obtaining a plurality of semiconductor thin films 110.

[0053] Furthermore, it is preferable to remove the protective film 111 before etching the intermediate sacrificial layer 121. This is because, if the protective film 111 is removed after etching the intermediate sacrificial layer 121, the bonding force between the support layer 122 and the semiconductor thin film 110 is weak, and there is a possibility that the semiconductor thin film 110 may detach during the removal process of the protective film 111.

[0054] However, if the protective film 111 and the intermediate sacrificial layer 121 are formed from the same type of material, the removal of the protective film 111 and the etching of the intermediate sacrificial layer 121 may be performed in the same process.

[0055] Figures 11(A) and (B) are cross-sectional views showing the process of selectively separating the semiconductor thin film 110 from the intermediate substrate 120. As shown in Figures 11(A) and (B), in step S110 (Figure 1), the semiconductor thin film 110 is selectively separated from the intermediate substrate 120 using the second transfer substrate 130.

[0056] The second transfer substrate 130, like the first transfer substrate 112, is formed of, for example, Si, glass, or quartz. On the lower surface of the second transfer substrate 130 (the surface facing the intermediate substrate 120), a stamp 131 is provided as a transfer holding part at a position aligned with the target semiconductor thin film 110. The stamp 131 is an adhesive material and is formed of, for example, a silicone elastomer such as polydimethylsiloxane (PDMS).

[0057] As described above, the semiconductor thin film 110 is supported on the support layer 122 on the intermediate substrate 120, and a gap 123 is formed between the lower surface of the semiconductor thin film 110 and the intermediate substrate 120, so the semiconductor thin film 110 can be easily separated from the support layer 122. In particular, since the central portion of the lower surface of the semiconductor thin film 110 is bonded to the support layer 122, the semiconductor thin film 110 can be easily separated from its outer periphery.

[0058] As shown in Figure 11(A), the stamp 131 of the second transfer substrate 130 is bonded to the target semiconductor thin film 110. Since the stamp 131 is adhesive, the bonding force between the stamp 131 and the upper surface of the semiconductor thin film 110 is stronger than the bonding force between the lower surface of the semiconductor thin film 110 and the support layer 122 (the weak intermolecular force described above).

[0059] Therefore, as shown in Figure 11(B), when the second transfer substrate 130 is moved upward, that is, away from the intermediate substrate 120, the semiconductor thin film 110 bonded to the stamp 131 separates from the support layer 122 of the intermediate substrate 120. On the other hand, the semiconductor thin film 110 that was not bonded to the stamp 131 remains on the support layer 122 of the intermediate substrate 120. In other words, the semiconductor thin film 110 is selectively separated from the intermediate substrate 120.

[0060] Figure 12(A) is a cross-sectional view showing the process of bonding the semiconductor thin film 110 to the device substrate 140. As shown in Figure 12(A), in step S111 (Figure 1), the semiconductor thin film 110 held by the second transfer substrate 130 is bonded to the device substrate 140.

[0061] The device substrate 140 is formed of, for example, Si. It is desirable that the upper surface of the device substrate 140 has a smooth surface with a surface roughness of 10 nm or less. Furthermore, it is desirable that the lower surface of the semiconductor thin film 110 (i.e., the lower surface of the lower cladding layer 104) and the upper surface of the device substrate 140 be cleaned before bonding.

[0062] After bonding the semiconductor thin film 110 to the device substrate 140, the stamp 131 of the second transfer substrate 130 is peeled off from the upper surface of the semiconductor thin film 110. Since the stamp 131 is bonded to the semiconductor thin film 110 by its adhesive properties, it can be peeled off from the semiconductor thin film 110 by applying upward force.

[0063] After peeling the second transfer substrate 130 from the semiconductor thin film 110, a predetermined heat treatment is performed with the lower surface of the semiconductor thin film 110 in close contact with the upper surface of the device substrate 140, thereby enabling a strong intermolecular bond between the lower surface of the semiconductor thin film 110 and the upper surface of the device substrate 140.

[0064] Figure 12(B) is a cross-sectional view showing the process of forming electrodes 141 and 142 on the device substrate 140. As shown in Figure 12(B), in step S112 (Figure 1), the first electrode 141 is formed on the contact layer 107 of the semiconductor thin film 110, and the second electrode 142 is formed on the device substrate 140 at a position in contact with the side surface of the lower cladding layer 104. In addition, a wiring layer may be formed as needed.

[0065] The electrodes 141 and 142 are formed from metallic materials such as Au (gold), Al (aluminum), Cu (copper), Ti, and Pt. This forms the semiconductor device 1. The semiconductor device is, for example, a photodiode or an LED.

[0066] Furthermore, the semiconductor thin film 110 remaining on the intermediate substrate 120 in Figure 11(B) can be separated from the intermediate substrate 120 using the second transfer substrate 130 and then transferred to another device substrate. In other words, multiple semiconductor thin films 110 on the intermediate substrate 120 can be selected at arbitrary intervals and transferred to any number of device substrates.

[0067] <Operation> In Embodiment 1, since the semiconductor thin film 110 is transferred from the growth substrate 101 to the intermediate substrate 120 (see Figure 10), the semiconductor thin film 110 can be held on the support layer 122 of the intermediate substrate 120 while maintaining the smoothness of the lower surface of the semiconductor thin film 110.

[0068] Furthermore, since the semiconductor thin film 110 is supported by the support layer 122 and a gap 123 is formed between the lower surface of the semiconductor thin film 110 and the intermediate substrate 120, the semiconductor thin film 110 can be easily separated from the support layer 122, and selective transfer of the semiconductor thin film 110 from the intermediate substrate 120 to the device substrate 140 can be easily performed.

[0069] In the conventional technology (see Patent Document 1), a semiconductor thin film and a support layer were formed on a growth substrate, and then the support layer was broken to separate the semiconductor thin film from the growth substrate and transfer it to a device substrate. Therefore, it was necessary to form a support layer on the growth substrate and to remove the fragments of the support layer remaining on the growth substrate after the transfer of the semiconductor thin film. In Embodiment 1, these steps are unnecessary, thus simplifying the manufacturing process of the semiconductor device 1.

[0070] Furthermore, in order to separate the semiconductor thin film 110 from the growth substrate 101 and bond it to the intermediate substrate 120, the lower surface of the semiconductor thin film 110 separated from the growth substrate 101 can be subjected to a predetermined treatment before bonding it to the intermediate substrate 120. In this embodiment, the predetermined treatment is the removal of the stop layer 103 shown in Figure 7. However, the predetermined treatment is not limited to the removal of the stop layer 103, but may also be, for example, cleaning or polishing (mechanical polishing, chemical polishing), or the formation of a metal film. The formation of a metal film will be described in Embodiment 3.

[0071] Furthermore, since the semiconductor thin film 110 on the growth substrate 101 is transferred to the intermediate substrate 120 all at once, and the semiconductor thin film 110 on the intermediate substrate 120 is selectively transferred to the device substrate 140, the spacing of the semiconductor thin film 110 on the growth substrate 101 can be set independently of the spacing of the semiconductor thin film 110 on the device substrate 140. As a result, the semiconductor thin film 110 can be densely integrated on the growth substrate 101, and the utilization efficiency of the growth substrate 101 and each semiconductor layer can be improved.

[0072] Furthermore, the process of selectively transferring multiple semiconductor thin films 110 on the intermediate substrate 120 to the device substrate 140 (Figures 11(A), (B)) can be performed continuously using a single semiconductor manufacturing apparatus (transfer apparatus), thus enabling a highly efficient transfer process of the semiconductor thin films 110 to the device substrate 140.

[0073] <Effects of Embodiment 1> The manufacturing method of the semiconductor support structure 10 of this embodiment (steps S101 to S109 in Figure 1) includes the steps of: forming a plurality of semiconductor thin films 110 by dividing a semiconductor layer formed by crystal growth on a growth substrate 101; removing the growth substrate 101; bonding the plurality of semiconductor thin films 110 to an intermediate sacrificial layer (sacrificial layer) 121 formed on an intermediate substrate 120; and forming a plurality of support layers 122 that support the plurality of semiconductor thin films 110 by partially removing the intermediate sacrificial layer 121, thereby forming a gap 123 between the lower surface (the surface facing the intermediate substrate 120: the first surface) of each semiconductor thin film 110 and the intermediate substrate 120.

[0074] Therefore, multiple semiconductor thin films 110 can be separated from the growth substrate 101 all at once, the semiconductor thin films 110 that have undergone the above processing can be bonded to the intermediate substrate 120 and supported by the support layer 122. This makes it possible to manufacture a semiconductor support structure 10 that can selectively transfer the semiconductor thin films 110 that have undergone the predetermined processing to the device substrate 140.

[0075] In other words, when it is necessary to perform a predetermined process on multiple semiconductor thin films 110 separated from the growth substrate 101, the multiple semiconductor thin films 110 are separated from the growth substrate 101 all at once, and the multiple semiconductor thin films 110 are supported in a peelable manner by the support layer 122 on the intermediate substrate 120, making it possible to perform the predetermined process on the multiple semiconductor thin films 110 all at once. As a result, they can be efficiently and selectively transferred onto the device substrate 140. That is, the semiconductor thin films 110 can be easily separated from the support layer 122, and the process of selectively transferring the semiconductor thin films 110 to the device substrate 140 can be carried out efficiently.

[0076] Furthermore, since the support layer 122 is formed inward from the outer periphery of the lower surface (first surface) of the semiconductor thin film 110, the semiconductor thin film 110 on the support layer 122 can be easily separated from its outer periphery.

[0077] Furthermore, since a step of covering the semiconductor thin film 110 with a protective film 111 is provided after the step of forming the semiconductor thin film 110, and a step of removing the protective film 111 is provided after the step of bonding the semiconductor thin film 110 to the intermediate sacrificial layer 121, the semiconductor thin film 110 can be protected from erosion by etching during the removal step of the growth substrate 101. Also, since the protective film 111 is removed on the intermediate substrate 120, the step of removing the protective film 111 on the device substrate 140 is unnecessary. This prevents damage to the device substrate 140 by the etchant used to remove the protective film 111. Similar effects can be obtained in embodiments 2 to 11 described later, even when the protective film is removed on the intermediate substrate (for example, in steps S210, S309, S408, S508, S607, S709, S809, S908, etc.).

[0078] Furthermore, the method for manufacturing the semiconductor device 1 of this disclosure includes the steps of selectively separating a plurality of semiconductor thin films 110 of the semiconductor support structure 10 from the support layer 122 and bonding the semiconductor thin films 110 to the device substrate 140. Therefore, as in the prior art, there is no need to form a support layer on the growth substrate 101, nor is there a need to remove fragments of the support layer from the growth substrate 101 after the transfer of the semiconductor thin films 110. Accordingly, the transfer process of the semiconductor thin films 110 can be carried out more efficiently.

[0079] Furthermore, the semiconductor support structure 10 of this disclosure (Figure 10) includes an intermediate substrate 120 as a substrate, a plurality of support layers 122 formed on the intermediate substrate 120, and a plurality of semiconductor thin films 110 formed by crystal growth on a growth substrate 101 different from the intermediate substrate 120 and supported by the plurality of support layers 122. A gap 123 is formed between the lower surface (the surface facing the intermediate substrate 120) of each semiconductor thin film 110 and the intermediate substrate 120. Therefore, the semiconductor thin films 110 can be easily separated from the support layers 122, and the subsequent transfer process to the device substrate 140 can be facilitated.

[0080] <Embodiment 2> Figure 13 is a flowchart showing the method for manufacturing a semiconductor device according to Embodiment 2. Figure 14 is a cross-sectional view showing the process of forming each semiconductor layer, including the semiconductor thin film 210, on the growth substrate 201.

[0081] In step S201 (Figure 13), as shown in Figure 14, a buffer layer 202, a first stop layer 203, a second stop layer 204, a third stop layer 205, a lower cladding layer 206, an active layer 207, an upper cladding layer 208, and a contact layer 209 are sequentially formed on the growth substrate 201 by epitaxial growth. The structure on which each layer 202 to 209 is formed on the growth substrate 201 is also referred to as a laminated substrate 200.

[0082] Of these, the lower cladding layer 206, the active layer 207, the upper cladding layer 208, and the contact layer 209 constitute the semiconductor thin film 210. The semiconductor thin film 210 is also referred to as the semiconductor crystal layer or functional layer. Furthermore, the semiconductor thin film 210 before patterning (Figures 15(A) to (C)), which will be described later, is also referred to as the semiconductor layer. The stop layers 203 to 205 are also referred to as predetermined layers.

[0083] The growth substrate 201 and the buffer layer 202 are formed in the same manner as the growth substrate 101 and buffer layer 102 of Embodiment 1, respectively.

[0084] Of the stop layers 203 to 205, the first stop layer 203 and the third stop layer 205 are formed from a material that is not removed by the etchant used to remove the growth substrate 201 (step S205). The second stop layer 204 is formed from a material that is not removed by the etchant used to remove the first stop layer 203 (step S206) (for example, the same material as the growth substrate 201).

[0085] Specifically, the first stop layer 203 is made of i-InGaAs. The second stop layer 204 is made of i-InP. The third stop layer 205 is made of i-InGaAs. The thickness of each of the stop layers 203, 204, and 205 is, for example, several hundred nm to 1 μm.

[0086] The lower cladding layer 206, the active layer 207, the upper cladding layer 208, and the contact layer 209 are formed in the same manner as the lower cladding layer 104, the active layer 105, the upper cladding layer 106, and the contact layer 107 of Embodiment 1, respectively.

[0087] Figures 15(A) and (B) are a cross-sectional view and a plan view showing the process of patterning the semiconductor thin film 210. Figure 15(C) is an enlarged view of the area enclosed by the dashed line P1 in Figure 15(A).

[0088] As shown in Figures 15(A) and (B), in step S202 (Figure 13), the semiconductor thin film 210 is etched along a predetermined separation region to form a grid-like groove G1. Figures 15(A) and (B) show the portion of the semiconductor thin film 210 separated into 4 rows and 4 columns (16 regions).

[0089] As shown in Figure 15(C), the semiconductor thin film 210 is patterned by etching that extends from the contact layer 209 to the third stop layer 205. The etching method is the same as the patterning process for the semiconductor thin film 110 in Embodiment 1.

[0090] Figure 16 is a cross-sectional view showing the process of forming a protective film 211 that covers the semiconductor thin film 210. In step S203 (Figure 13), as shown in Figure 16, a protective film 211 is formed so as to cover the semiconductor thin film 210. The protective film 211 covers the top and side surfaces of the semiconductor thin film 210. The material and method of forming the protective film 211 are the same as those of the protective film 111 in Embodiment 1.

[0091] Figure 17 is a cross-sectional view showing the process of attaching the semiconductor thin film 210 to the first transfer substrate 212. In step S204 (Figure 13), as shown in Figure 17, the protective film 211 on the semiconductor thin film 210 is attached to the adhesive layer 213 provided on the first transfer substrate 212.

[0092] The first transfer substrate 212 and adhesive layer 213 are formed in the same manner as the first transfer substrate 112 and adhesive layer 113 of Embodiment 1, respectively.

[0093] Figure 18 is a cross-sectional view showing the process of separating the semiconductor thin film 210 by removing the growth substrate 201. In step S205 (Figure 13), as shown in Figure 18, the semiconductor thin film 210 is separated by wet etching to remove the growth substrate 201 and the buffer layer 202 from the bottom surface (the surface opposite to the semiconductor thin film 210).

[0094] For wet etching, the same etchant as in the removal process for the growth substrate 101 in Embodiment 1 can be used. By completely removing the growth substrate 201 and the buffer layer 202, the semiconductor thin film 210 is separated from them.

[0095] Figure 19(A) is a cross-sectional view showing the process of removing the first stop layer 203. In step S206 (Figure 13), the first stop layer 203 (InGaAs) is removed by wet etching. As the etchant, an etchant is used in which the etching rate of InGaAs is greater than that of InP. For example, phosphoric acid, or a mixture of phosphoric acid and hydrogen peroxide, can be used.

[0096] Figure 19(B) is a cross-sectional view showing the process of removing the second stop layer 204. In step S207 (Figure 13), the second stop layer 204 (InP) is removed by wet etching. The same etchant used for removing the growth substrate 201 can be used as the etchant. For example, hydrochloric acid, a mixture of hydrochloric acid and phosphoric acid, or a mixture of hydrochloric acid and nitric acid can be used.

[0097] Figure 19(C) is a cross-sectional view showing the process of removing the third stop layer 205. In step S208 (Figure 13), the third stop layer 205 (InGaAs) is removed by wet etching. The same etchant used for removing the first stop layer 203 can be used as the etchant. For example, phosphoric acid, or a mixture of phosphoric acid and hydrogen peroxide, can be used.

[0098] In Embodiment 2, the reason for forming three stop layers 203, 204, and 205 and removing them in a three-stage etching process is as follows: The growth substrate 201 generally has a thickness of 100 μm or more, and since it takes time to completely remove the growth substrate 201 by etching, variations in etching depth are likely to occur.

[0099] In the case where there is only one stop layer 103 (Figure 6) between the growth substrate 101 and the semiconductor thin film 110, as in Embodiment 1, variations in etching depth may cause variations in the thickness of the stop layer 103 when the removal of the growth substrate 101 and the buffer layer 102 is completed. Therefore, when the stop layer 103 is removed by etching in the next step, the lower surface of the semiconductor thin film 110 may be partially eroded, potentially reducing its smoothness.

[0100] In contrast, in Embodiment 2, etching to remove the growth substrate 201 and buffer layer 202 is stopped at the first stop layer 203, etching to remove the first stop layer 203 is stopped at the second stop layer 204, and etching to remove the second stop layer 204 is stopped at the third stop layer 205. By performing etching in three stages in this way, the variation in etching depth can be suppressed to 10 nm or less, and the smoothness of the lower surface of the semiconductor thin film 210 can be improved.

[0101] Furthermore, the etching rates in the removal processes of the growth substrate 201 and the stop layers 203-205 may be varied. The etching rate can be adjusted, for example, by changing the concentration of the etchant.

[0102] After removing the stop layers 203 to 205, the semiconductor thin film 210 is bonded to the intermediate substrate (step S209), the first transfer substrate and protective film are removed (step S210), the intermediate sacrificial layer of the intermediate substrate is partially removed by etching (step S211), the semiconductor thin film 210 is selectively separated from the intermediate substrate and bonded to the device substrate (steps S212, S213), and electrodes and the like are formed (step S214). These steps are the same as steps S107 to S112 of Embodiment 1.

[0103] Steps S201 to S211 yield a semiconductor support structure similar to the semiconductor support structure 10 of Embodiment 1 (Figure 10). Steps S201 to S211 correspond to a method for manufacturing the semiconductor support structure. Steps S201 to S205 correspond to a process for obtaining a plurality of semiconductor thin films 210.

[0104] Here, we have described the case in which three stop layers 203 to 205 are formed on the growth substrate 201. However, by forming two or more stop layers on the growth substrate 201 and removing them in at least two etching steps, the effect of suppressing the variation in etching depth described above can be obtained.

[0105] As described above, in Embodiment 2, a semiconductor thin film 210 is formed on the growth substrate 201 via two or more stop layers (for example, three stop layers 203 to 205), and the stop layers are removed in at least two etching steps. Therefore, variations in etching depth during the removal process of the growth substrate 201, which has a thickness of 100 μm or more, can be suppressed. This improves the smoothness of the lower surface of the semiconductor thin film 210 and improves the transferability of the semiconductor thin film 210 to the device substrate.

[0106] <Embodiment 3> Figure 20 is a flowchart showing the method for manufacturing a semiconductor device according to Embodiment 3. Figure 21 is a cross-sectional view showing the process of forming each semiconductor layer, including the semiconductor thin film 310, on the growth substrate 301.

[0107] In step S301 (Figure 20), as shown in Figure 21, a buffer layer 302, a stop layer 303, a lower cladding layer 304, an active layer 305, an upper cladding layer 306, and a contact layer 307 are sequentially formed on the growth substrate 301 by epitaxial growth. The structure on which each layer 302 to 307 is formed on the growth substrate 301 is also referred to as a laminated substrate 300.

[0108] Of these, the lower cladding layer 304, the active layer 305, the upper cladding layer 306, and the contact layer 307 constitute the semiconductor thin film 310. The semiconductor thin film 310 is also referred to as the semiconductor crystal layer or the functional layer. Furthermore, the semiconductor thin film 310 before patterning (Figures 22(A) to (C)), which will be described later, is also referred to as the semiconductor layer. The stop layer 303 is also referred to as the predetermined layer.

[0109] The growth substrate 301, buffer layer 302, and stop layer 303 are formed in the same manner as the growth substrate 101, buffer layer 102, and stop layer 103 of Embodiment 1.

[0110] Furthermore, the lower cladding layer 304, the active layer 305, the upper cladding layer 306, and the contact layer 307 are formed in the same manner as the lower cladding layer 104, the active layer 105, the upper cladding layer 106, and the contact layer 107 of Embodiment 1, respectively.

[0111] Figures 22(A) and (B) are a cross-sectional view and a plan view showing the process of patterning the semiconductor thin film 310. Figure 22(C) is an enlarged view of the area enclosed by the dashed line P1 in Figure 22(A).

[0112] As shown in Figures 22(A) and (B), in step S302 (Figure 20), the semiconductor thin film 310 is etched along a predetermined separation region to form a grid-like groove G1. Figures 22(A) and (B) show the portion of the semiconductor thin film 310 that has been separated into 4 rows and 4 columns (16 regions).

[0113] As shown in Figure 22(C), the semiconductor thin film 310 is patterned by etching that reaches from the contact layer 307 to the stop layer 303. The etching method is the same as the patterning process for the semiconductor thin film 110 in Embodiment 1.

[0114] Figure 23 is a cross-sectional view showing the process of forming a protective film 311 that covers the semiconductor thin film 310. In step S303 (Figure 20), as shown in Figure 23, a protective film 311 is formed so as to cover the semiconductor thin film 310. The protective film 311 covers the top and side surfaces of the semiconductor thin film 310. The material and method of forming the protective film 311 are the same as those of the protective film 111 in Embodiment 1.

[0115] Figure 24 is a cross-sectional view showing the process of attaching the semiconductor thin film 310 to the first transfer substrate 312. In step S304 (Figure 20), as shown in Figure 24, the protective film 311 on the semiconductor thin film 310 is attached to the adhesive layer 313 provided on the first transfer substrate 312.

[0116] The first transfer substrate 312 and adhesive layer 313 are formed in the same manner as the first transfer substrate 112 and adhesive layer 113 of Embodiment 1, respectively.

[0117] Figure 25 is a cross-sectional view showing the process of separating the semiconductor thin film 310 by removing the growth substrate 301. In step S305 (Figure 20), as shown in Figure 25, the semiconductor thin film 310 is separated by wet etching to remove the growth substrate 301 and the buffer layer 302 from the bottom surface (the surface opposite to the semiconductor thin film 310).

[0118] For wet etching, the same etchant as in the removal step of the growth substrate 101 in Embodiment 1 can be used. By completely removing the growth substrate 301 and the buffer layer 302, the semiconductor thin film 310 is separated from them.

[0119] Figure 26 is a cross-sectional view showing the process of removing the stop layer 303. In step S306 (Figure 20), the stop layer 303 is removed by wet etching. For wet etching, the same etchant as in the process of removing the stop layer 103 in Embodiment 1 can be used. Removal of the stop layer 303 exposes the lower surface of the semiconductor thin film 310 (more specifically, the lower surface of the lower cladding layer 304).

[0120] In this embodiment, the step of removing the stop layer 303 is not necessarily required. That is, if the semiconductor thin film 310 can be formed on the buffer layer 302 without providing the stop layer 303, then the stop layer 303 may not be provided. Alternatively, the metal film 315, described later, may be formed on the underside of the stop layer 303 without removing the stop layer 303 from the state shown in Figure 25. In this case, in order to separate (fragment) the stop layer 303 in the same way as the semiconductor thin film 310, it is desirable to perform etching in the patterning step of the semiconductor thin film 310 (step S302) until the groove G1 (Figure 22(C)) penetrates the stop layer 303.

[0121] Figure 27 is a cross-sectional view showing the process of forming a metal film 315 on the lower surface of the semiconductor thin film 310. As shown in Figure 27, in step S307 (Figure 20), a metal film 315 is formed on the lower surface of the lower cladding layer 104 of the semiconductor thin film 310.

[0122] The metal film 315 is formed on the underside of the undercladding layer 304 of the semiconductor thin film 310, for example, by sputtering or deposition. The thickness of the metal film 315 is, for example, several tens of nanometers to 1 μm. The surface roughness of the underside of the metal film 315 is preferably 10 nm or less.

[0123] The metal film 315 is formed from, for example, Au, AuGe (gold germanium), AuGeNi (gold germanium nickel), NiAu (nickel gold), AuSn (gold tin), TiAu (titanium gold), TiPtAu (titanium platinum gold), etc.

[0124] Figure 28 is a cross-sectional view showing the process of bonding the semiconductor thin film 310 to the intermediate substrate 320. As shown in Figure 28, in step S308 (Figure 20), the semiconductor thin film 310 held by the first transfer substrate 312 is bonded to the intermediate substrate 320.

[0125] The intermediate substrate 320 and the intermediate sacrificial layer 321 are formed in the same manner as the intermediate substrate 120 and the intermediate sacrificial layer 121 described in Embodiment 1.

[0126] Figure 29 is a cross-sectional view showing the process of removing the first transfer substrate 312. In step S309 (Figure 20), as shown in Figure 29, the first transfer substrate 312 is removed from the semiconductor thin film 310 bonded to the intermediate substrate 320. The method for removing the first transfer substrate 312 is the same as the method for removing the first transfer substrate 112 in Embodiment 1.

[0127] After removing the first transfer substrate 312, the protective film 311 covering the semiconductor thin film 310 is removed. The method for removing the protective film 311 is the same as the method for removing the protective film 111 in Embodiment 1.

[0128] Figure 30 is a cross-sectional view showing the process of partially removing the intermediate sacrificial layer 321 of the intermediate substrate 320 by etching. As shown in Figure 30, in step S310 (Figure 20), the intermediate sacrificial layer 321 of the intermediate substrate 320 is partially removed by etching. The etching method is the same as that used for etching the intermediate sacrificial layer 121 in Embodiment 1.

[0129] The portion of the intermediate sacrificial layer 321 that is not removed by etching, that is, the portion located beneath each semiconductor thin film 310, is referred to as the support layer 322. On the intermediate substrate 320, each semiconductor thin film 310 is supported by the support layer 322. In addition, a gap 323 is formed between the lower surface of the metal film 315 provided on each semiconductor thin film 310 and the intermediate substrate 320.

[0130] In this way, a semiconductor support structure 30 is obtained in which the semiconductor thin films 310 are supported on each support layer 322 on the intermediate substrate 320, and a gap 323 is formed between the lower surface of the metal film 315 of each semiconductor thin film 310 and the intermediate substrate 320. Each support layer 322 is joined to the center of the lower surface of the metal film 315 of the semiconductor thin film 310. Steps S301 to S310 shown in Figure 20 correspond to the manufacturing method of the semiconductor support structure 30. Steps S301 to S305 correspond to the process of obtaining a plurality of semiconductor thin films 310.

[0131] Figures 31(A) and (B) are cross-sectional views showing the process of selectively separating the semiconductor thin film 310 from the intermediate substrate 320. As shown in Figures 31(A) and (B), in step S311 (Figure 20), the semiconductor thin film 310 is selectively separated from the intermediate substrate 320 using the second transfer substrate 330.

[0132] The second transfer substrate 330 and stamp 331 are formed in the same manner as the second transfer substrate 130 and stamp 131 of Embodiment 1, respectively.

[0133] As shown in Figure 31(A), the stamp 331 of the second transfer substrate 330 is bonded to the target semiconductor thin film 310. As shown in Figure 31(B), when the second transfer substrate 330 is moved upward, that is, away from the intermediate substrate 320, the semiconductor thin film 310 bonded to the stamp 331 separates from the support layer 322 of the intermediate substrate 320.

[0134] Figure 32(A) is a cross-sectional view showing the process of bonding the semiconductor thin film 310 to the device substrate 340. As shown in Figure 32(A), in step S312 (Figure 20), the metal film 315 on the lower surface of the semiconductor thin film 310 held by the second transfer substrate 330 is bonded to the device substrate 340.

[0135] The device substrate 340 is, for example, a Si substrate. A wiring layer 341 is formed on the upper surface of the device substrate 340. The wiring layer 341 is connected to an electrical circuit (drive circuit) that drives the semiconductor thin film 310.

[0136] The metal film 315 bonded to the lower surface of the semiconductor thin film 310 is brought into close contact with the wiring layer 341 of the device substrate 340.

[0137] After bonding the metal film 315 of the semiconductor thin film 310 to the wiring layer 341, the stamp 331 of the second transfer substrate 330 is peeled off from the upper surface of the semiconductor thin film 310. Since the stamp 331 is bonded to the semiconductor thin film 310 due to its adhesive properties, it can be peeled off from the semiconductor thin film 310 by applying upward force.

[0138] After peeling the second transfer substrate 330 from the semiconductor thin film 310, the metal film 315 and the wiring layer 341 are bonded by performing a predetermined heat treatment. Since the bond between the metal film 315 and the wiring layer 341 is a metal-to-metal bond and is subject to a certain degree of deformation, the bond between the two can be made strong.

[0139] Figure 32(B) is a cross-sectional view showing the process of forming electrodes 342 on a device substrate 340. As shown in Figure 32(B), in step S313 (Figure 20), electrodes 342 are formed on the upper surface of the contact layer 307 of the semiconductor thin film 310, and wiring and the like are formed as necessary. The electrodes 342 are formed of the same metallic material as electrodes 141 and 142 in Embodiment 1.

[0140] By bonding the semiconductor thin film 310 to the device substrate 340, the metal film 315 and the wiring layer 341 are electrically connected, thus reducing the amount of wiring work required after bonding the semiconductor thin film 310 to the device substrate 340.

[0141] This forms a semiconductor device 3. The semiconductor device 3 is, for example, a photodiode or an LED.

[0142] As described above, in Embodiment 3, since the metal film 315 is formed on the lower surface of the semiconductor thin film 310 (i.e., the lower surface of the lower cladding layer 304), the metal film 315 and the wiring layer 341 are electrically connected when the semiconductor thin film 310 is transferred to the device substrate 340. Therefore, the process of forming wiring and the like on the device substrate 340 can be simplified.

[0143] <Embodiment 4> Figure 33 is a flowchart showing the method for manufacturing a semiconductor device according to Embodiment 4. Figure 34 is a cross-sectional view showing the process of forming each semiconductor layer, including the semiconductor thin film 410, on the growth substrate 401.

[0144] In step S401 (Figure 33), as shown in Figure 34, a buffer layer 402, a sacrificial layer 403, a stop layer 404, a lower cladding layer 405, an active layer 406, an upper cladding layer 407, and a contact layer 408 are sequentially formed on the growth substrate 401 by epitaxial growth. The substrate 401 with each of the layers 402 to 408 formed on it is also called a laminated substrate 400.

[0145] Of these, the lower cladding layer 405, the active layer 406, the upper cladding layer 407, and the contact layer 408 constitute the semiconductor thin film 410. The semiconductor thin film 410 is also referred to as the semiconductor crystal layer or the functional layer. Furthermore, the semiconductor thin film 410 before patterning (Figures 35(A) to (C)), which will be described later, is also referred to as the semiconductor layer. The stop layer 404 is also referred to as the predetermined layer.

[0146] The growth substrate 401 and the buffer layer 402 are formed in the same manner as the growth substrate 101 and buffer layer 102 of Embodiment 1, respectively.

[0147] The sacrificial layer 403 is formed of InP. The thickness of the sacrificial layer 403 is, for example, several hundred nm to 1 μm. The sacrificial layer 403 is a layer that is removed in the process (step S405) of separating the semiconductor thin film 410 from the growth substrate 401, which will be described later.

[0148] The stop layer 404 is formed of i-InGaAs. The thickness of the stop layer 404 is such that etching can be stopped in the etching steps S402 and S405 described later, and is, for example, several hundred nm to 1 μm.

[0149] The lower cladding layer 405, the active layer 406, the upper cladding layer 407, and the contact layer 408 are formed in the same manner as the lower cladding layer 104, the active layer 105, the upper cladding layer 106, and the contact layer 107 of Embodiment 1, respectively.

[0150] Figures 35(A) and (B) are a cross-sectional view and a plan view showing the process of patterning the semiconductor thin film 410. Figure 35(C) is an enlarged view of the area enclosed by the dashed line P1 in Figure 35(A).

[0151] As shown in Figures 35(A) and (B), in step S402 (Figure 33), the semiconductor thin film 410 is etched along a predetermined separation region to form a grid-like groove G1. Figures 35(A) and (B) show the portion of the semiconductor thin film 410 that has been separated into 4 rows and 4 columns (16 regions).

[0152] As shown in Figure 35(C), the semiconductor thin film 410 is patterned by etching that reaches from the contact layer 408 to the sacrificial layer 403. The etching method is the same as the patterning process for the semiconductor thin film 110 in Embodiment 1.

[0153] Here, a two-stage etching process is performed so that a portion of the stop layer 404 (referred to as the stepped portion 404a) protrudes from the outer periphery (side surface) of the semiconductor thin film 410. That is, by etching up to a certain point in the stop layer 404 and then etching up to the lower cladding layer 405, the stepped portion 404a can be formed in the stop layer 404.

[0154] Figure 36 is a cross-sectional view showing the process of forming a protective film 411 that covers the semiconductor thin film 410. In step S403 (Figure 33), as shown in Figure 36, a protective film 411 is formed so as to cover the semiconductor thin film 410. The material and method of forming the protective film 411 are the same as those of the protective film 111 in Embodiment 1.

[0155] The protective film 411 covers the top and sides of the semiconductor thin film 410. The protective film 411 is formed so as to rest on the stepped portion 404a (Figure 35(C)) of the stop layer 404. This is to ensure that the protective film 411 does not cover the sacrificial layer 403 as much as possible.

[0156] Figure 37 is a cross-sectional view showing the process of attaching the semiconductor thin film 410 to the first transfer substrate 412. In step S404 (Figure 33), as shown in Figure 37, the protective film 411 on the semiconductor thin film 410 is attached to the adhesive layer 413 provided on the first transfer substrate 412.

[0157] The first transfer substrate 412 and adhesive layer 413 are formed in the same manner as the first transfer substrate 112 and adhesive layer 113 of Embodiment 1, respectively.

[0158] Figure 38 is a cross-sectional view showing the process of separating the semiconductor thin film 410 by removing the sacrificial layer 403. As shown in Figure 38, in step S405 (Figure 33), the semiconductor thin film 410 is separated from the growth substrate 401 by removing the sacrificial layer 403 by wet etching.

[0159] As the etchant, one with a high selectivity ratio between InP (sacrificial layer 403) and InGaAs (stop layer 404) is used. More specifically, an etchant with an etching rate of InP greater than that of InGaAs is used. Furthermore, the etchant must not etch the protective film 411, the first transfer substrate 412, and the adhesive layer 413. Such an etchant can be hydrochloric acid, a mixture of hydrochloric acid and phosphoric acid, or a mixture of hydrochloric acid and nitric acid.

[0160] This allows etching to be stopped at the stop layer 404. The semiconductor thin film 410 is separated from the growth substrate 401 by the complete removal of the sacrificial layer 403. During wet etching, the semiconductor thin film 410 is held on the first transfer substrate 412.

[0161] Figure 39 is a cross-sectional view showing the process of removing the stop layer 404. In step S406 (Figure 33), the stop layer 404 is removed by wet etching. The etchant used to remove the stop layer 103 in Embodiment 1 can be used as the etchant.

[0162] After removing the stop layer 404, the semiconductor thin film 410 is bonded to the intermediate substrate (step S407), the first transfer substrate and protective film are removed (step S408), the intermediate sacrificial layer of the intermediate substrate is partially removed by etching (step S409), the semiconductor thin film 410 is selectively separated from the intermediate substrate and bonded to the device substrate (steps S410, S411), and electrodes and the like are formed (step S412). These steps are the same as steps S107 to S112 of Embodiment 1.

[0163] Steps S401 to S409 yield a semiconductor support structure similar to the semiconductor support structure 10 of Embodiment 1 (Figure 10). Steps S401 to S409 correspond to a method for manufacturing the semiconductor support structure. Steps S401 to S405 correspond to a process for obtaining a plurality of semiconductor thin films 410.

[0164] As described above, in Embodiment 4, the semiconductor thin film 410 is separated from the growth substrate 401 by removing the sacrificial layer 403. Therefore, it is not necessary to remove the semiconductor thin film 410 by etching, which shortens the etching time and makes the semiconductor device manufacturing process more efficient.

[0165] Modified Example. Figures 40(A) and (B) are cross-sectional and plan views showing modified semiconductor thin films 1610 and intermediate substrates 1620 applicable to embodiments 1 to 4. As shown in Figure 40(A), the modified semiconductor thin film 1610 is bonded to the intermediate sacrificial layer 1621 of the intermediate substrate 1620 in a bonding process corresponding to step S107 shown in Figure 1. Multiple grooves 1625 are formed in advance in the intermediate sacrificial layer 1621 of the intermediate substrate 1620.

[0166] In other words, the manufacturing method of the modified semiconductor support structure 160 includes a step of forming a groove 1625 on the upper surface of the support layer 1622 (the surface opposite to the intermediate substrate 1620) before the step of bonding the semiconductor thin film 1610 to the support layer 1622. The groove 1625 can be formed, for example, by dry etching.

[0167] As shown in Figure 40(B), the groove portion 1625 is formed in a grid pattern in two mutually orthogonal directions (a first direction and a second direction) in a plane parallel to the upper surface of the intermediate substrate 1620. That is, the groove portion 1625 includes a groove portion 1625a extending in the first direction and a groove portion 1625b extending in the second direction.

[0168] The width of each groove 1625 is, for example, several micrometers to several tens of micrometers. The spacing (pitch) between adjacent grooves 1625 should be smaller than the arrangement pitch of the semiconductor thin film 1610 bonded to the intermediate substrate 1620.

[0169] The semiconductor thin film 1610 is bonded to the intermediate sacrificial layer 1621 so as to be located on the groove portion 1625 of the intermediate sacrificial layer 1621. The materials of the intermediate substrate 1620 and the intermediate sacrificial layer 1621 are the same as the materials of the intermediate substrate 120 and the intermediate sacrificial layer 121 described in Embodiment 1.

[0170] The semiconductor thin film 1610 has a lower cladding layer 1604, an active layer 1605, an upper cladding layer 1606, and a contact layer 1607. These are configured in the same way as the lower cladding layer 104, active layer 105, upper cladding layer 106, and contact layer 107 of the semiconductor thin film 110 of Embodiment 1.

[0171] Figure 41(A) is a cross-sectional view showing the intermediate sacrificial layer 1621 partially removed by etching. The etching method is as described in Embodiment 1. As shown in Figure 41(A), etching is carried out in a plane parallel to the upper surface of the intermediate substrate 1620 until the intermediate sacrificial layer 1621 is retracted inward from the outer periphery of the bottom layer (lower cladding layer 1604) of each semiconductor thin film 1610.

[0172] The portion of the intermediate sacrificial layer 1621 that is not removed by etching, i.e., the portion located beneath each semiconductor thin film 1610, is referred to as the support layer 1622. On the intermediate substrate 1620, each semiconductor thin film 1610 is supported by the support layer 1622. In addition, a gap 1623 is formed between the underside of each semiconductor thin film 1610 and the intermediate substrate 1620.

[0173] Since grooves 1625 are formed in the support layer 1622, the area of ​​the portion of the support layer 1622 that contacts the lower surface of the semiconductor thin film 1610 becomes smaller. In other words, the contact area between the support layer 1622 and the lower surface of the semiconductor thin film 1610 becomes smaller, and the bonding force between the two becomes weaker, so the semiconductor thin film 1610 can be easily separated from the support layer 1622.

[0174] In Figure 41(A), the central part of the upper surface of the support layer 1622 (the surface that is joined to the semiconductor thin film 1610) is convex, but the shape of the support layer 1622 is not limited to this shape. For example, as shown in Figure 41(B), at least one groove 1625 may be formed on the surface of the support layer 1622 that is joined to the semiconductor thin film 1610.

[0175] In this modified example, the support layer 1622 formed on the intermediate substrate 1620 has at least one groove 1625 on the surface that is bonded to the semiconductor thin film 1610, so that the semiconductor thin film 1610 can be easily separated from the support layer 1622. This makes the transfer process of the semiconductor thin film 1610 to the device substrate more efficient.

[0176] This modified example is applicable not only to embodiments 1 to 4 described above, but also to embodiments 5 to 15 described below.

[0177] <Embodiment 5> Figure 42 is a flowchart showing the method for manufacturing a semiconductor device according to Embodiment 5. Figure 43 is a cross-sectional view showing the process of forming each semiconductor layer, including the semiconductor thin film 510, on the growth substrate 501.

[0178] In step S501 (Figure 42), as shown in Figure 43, a stop layer 502, a sacrificial layer 503, a stop layer 504, a lower cladding layer 505, an active layer 506, an upper cladding layer 507, and a contact layer 508 are sequentially formed on the growth substrate 501 by epitaxial growth. The substrate 501 with each of the layers 502 to 508 formed on it is also called a laminated substrate 500.

[0179] Of these, the lower cladding layer 505, the active layer 506, the upper cladding layer 507, and the contact layer 508 constitute the semiconductor thin film 510. The semiconductor thin film 510 is also referred to as the semiconductor crystal layer or the functional layer. Furthermore, the semiconductor thin film 510 before patterning (Figures 44(A) and (B)), which will be described later, is also referred to as the semiconductor layer. The stop layer 504 is also referred to as the predetermined layer.

[0180] The growth substrate 501 is an InP substrate, similar to the growth substrate 101 in Embodiment 1. The stop layer 502 is formed of i-InGaAs, the sacrificial layer 503 is formed of InP, and the stop layer 504 is formed of i-InGaAs. The stop layer 502 is an etching stop layer on the growth substrate 101 side, and the stop layer 504 is an etching stop layer on the semiconductor thin film 510 side.

[0181] Furthermore, the lower cladding layer 505 is made of n-InP, the active layer 506 is made of i-InGaAs, the upper cladding layer 507 is made of p-InP, and the contact layer 508 is made of p-InGaAs.

[0182] Figures 44(A) and (B) are a cross-sectional view and a plan view showing the process of patterning the semiconductor thin film 510. In step S502 (Figure 42), as shown in Figures 44(A) and (B), the semiconductor thin film 510 is etched along pre-set separation regions to form a grid-like groove G1. Figures 44(A) and (B) show the portion of the semiconductor thin film 510 that has been separated into 4 rows and 4 columns (16 regions).

[0183] The semiconductor thin film 510 is patterned by etching from the contact layer 508 to the stop layer 504. The etching method is the same as the patterning process for the semiconductor thin film 110 in Embodiment 1 (dry etching). The thickness of the stop layer 504 is set to a thickness that allows the etching to be stopped at this time. Alternatively, the lower cladding layer 505 may be patterned by wet etching.

[0184] Figure 45 is a cross-sectional view showing the process of forming a protective film 511 that covers the semiconductor thin film 510. In step S503 (Figure 42), as shown in Figure 45, a protective film 511 is formed that covers the side and top surfaces of the semiconductor thin film 510. The material and method of forming the protective film 511 are the same as those of the protective film 111 in Embodiment 1.

[0185] Figure 46 is a cross-sectional view showing the process of attaching the semiconductor thin film 510 to the first transfer substrate 512. In step S504 (Figure 42), as shown in Figure 46, the protective film 511 on the semiconductor thin film 510 is attached to the adhesive layer 513 provided on the first transfer substrate 512. The first transfer substrate 512 and the adhesive layer 513 are the same as the first transfer substrate 112 and adhesive layer 113 in Embodiment 1.

[0186] Figure 47 is a cross-sectional view showing the process of separating the semiconductor thin film 510 by removing the sacrificial layer 503. As shown in Figure 47, in step S505 (Figure 42), the semiconductor thin film 510 is separated from the growth substrate 501 by removing the sacrificial layer 503 (InP) by wet etching. As the etchant, an etchant is used in which the etching rate of InP is greater than the etching rate of InGaAs and which does not erode the protective film 511, the first transfer substrate 512, and the adhesive layer 513 (for example, hydrochloric acid, a mixture of hydrochloric acid and phosphoric acid, or a mixture of hydrochloric acid and nitric acid).

[0187] The semiconductor thin film 510 is separated from the growth substrate 501 by the complete removal of the sacrificial layer 503. During wet etching, the semiconductor thin film 510 is held on the first transfer substrate 512.

[0188] Figure 48 is a cross-sectional view showing the process of removing the stop layer 504 of the semiconductor thin film 510 and the process of removing the stop layer 502 of the growth substrate 501 together. In step S506 (Figure 42), the stop layer 504 (InGaAs) of the semiconductor thin film 510 is removed by wet etching. As the etchant, an etchant is used in which the etching rate of InGaAs is greater than the etching rate of InP and does not erode the protective film 511, the first transfer substrate 512, and the adhesive layer 513 (for example, phosphoric acid, or a mixture of phosphoric acid and hydrogen peroxide).

[0189] In addition to step S506, in step S513 (Figure 42), the stop layer 502 (InGaAs) on the growth substrate 501 is removed by wet etching. As the etchant, an etchant is used in which the etching rate of InGaAs is greater than that of InP (for example, phosphoric acid, or a mixture of phosphoric acid and hydrogen peroxide).

[0190] The removal of the stop layer 502 smooths the surface of the growth substrate 501 (InP substrate). This makes it possible to reuse the growth substrate 501 as a substrate for epitaxial growth of semiconductor layers.

[0191] Although steps S506 and S513 are shown side-by-side in the flowchart of Figure 42, they do not necessarily need to be executed in parallel. Furthermore, the process in step S513 may be performed separately from the processes in Figure 42 (steps S501 to S512).

[0192] Subsequently, the semiconductor thin film 510 is bonded to the intermediate substrate (step S507), the first transfer substrate and protective film are removed (step S508), the intermediate sacrificial layer of the intermediate substrate is partially removed by etching (step S509), the semiconductor thin film 510 is selectively separated from the intermediate substrate and bonded to the device substrate (steps S510, S511), and electrodes and the like are formed (step S512). These steps are the same as steps S107 to S112 of Embodiment 1.

[0193] Steps S501 to S509 yield a semiconductor support structure similar to the semiconductor support structure 10 of Embodiment 1 (Figure 10). Steps S501 to S509 correspond to a method for manufacturing the semiconductor support structure. Steps S501 to S505 correspond to a process for obtaining a plurality of semiconductor thin films 510.

[0194] As described above, in Embodiment 5, since a stop layer 502 is formed on the upper surface of the growth substrate 501, the growth substrate 501 can be reused after the semiconductor thin film 510 has been separated from the growth substrate 501. In other words, in addition to the effects of Embodiment 1, the effect of being able to reuse the growth substrate 501 can be obtained.

[0195] <Embodiment 6> Figure 49 is a flowchart showing the method for manufacturing a semiconductor device according to Embodiment 6. Figure 50 is a cross-sectional view showing the process of forming each semiconductor layer, including the semiconductor thin film 610, on the growth substrate 601.

[0196] In step S601 (Figure 49), as shown in Figure 50, a stop layer 602, a sacrificial layer 603, a contact layer 604, a lower cladding layer 605, an active layer 606, and an upper cladding layer 607 are sequentially formed on the growth substrate 601 by epitaxial growth. The substrate 601 with each of the layers 602 to 607 formed on it is also called a laminated substrate 600.

[0197] Of these, the contact layer 604, the lower cladding layer 605, the active layer 606, and the upper cladding layer 607 constitute the semiconductor thin film 610. The semiconductor thin film 610 is also referred to as the semiconductor crystal layer or functional layer. Furthermore, the semiconductor thin film 610 before patterning (Figures 51(A) and (B)), which will be described later, is also referred to as the semiconductor layer.

[0198] The growth substrate 601 is an InP substrate, similar to the growth substrate 101 in Embodiment 1. The stop layer 602 is formed of i-InGaAs, and the sacrificial layer 603 is formed of InP. The contact layer 604 is formed of p-InGaAs, the lower cladding layer 605 is formed of p-InP, the active layer 606 is formed of i-InGaAs, and the upper cladding layer 607 is formed of n-InP. In other words, unlike Embodiments 1 to 5, the bottom layer of the semiconductor thin film 610 in Embodiment 6 is the contact layer 604 (p-InGaAs).

[0199] Figures 51(A) and (B) are a cross-sectional view and a plan view showing the process of patterning the semiconductor thin film 610. As shown in Figures 51(A) and (B), in step S602 (Figure 49), the semiconductor thin film 610 is etched along a predetermined separation region to form a grid-like groove G1. Figures 51(A) and (B) show a portion of the semiconductor thin film 610 separated into 4 rows and 4 columns (16 regions).

[0200] The semiconductor thin film 610 is patterned by etching that reaches from the contact layer 604 to the sacrificial layer 603. The etching method is the same as the patterning process for the semiconductor thin film 110 in Embodiment 1.

[0201] Figure 52 is a cross-sectional view showing the process of forming a protective film 611 that covers the semiconductor thin film 610. In step S603 (Figure 49), as shown in Figure 52, a protective film 611 is formed that covers the side and top surfaces of the semiconductor thin film 610. The material and method of forming the protective film 611 are the same as those of the protective film 111 in Embodiment 1.

[0202] Figure 53 is a cross-sectional view showing the process of attaching the semiconductor thin film 610 to the first transfer substrate 612. In step S604 (Figure 49), as shown in Figure 53, the protective film 611 on the semiconductor thin film 610 is attached to the adhesive layer 613 provided on the first transfer substrate 612. The first transfer substrate 612 and the adhesive layer 613 are formed in the same manner as the first transfer substrate 112 and adhesive layer 113 of Embodiment 1, respectively.

[0203] Figure 54 is a cross-sectional view showing the process of separating the semiconductor thin film 610 by removing the sacrificial layer 603. As shown in Figure 54, in step S605 (Figure 49), the semiconductor thin film 610 is separated from the growth substrate 601 by removing the sacrificial layer 603 (InP) by wet etching. As the etchant, an etchant is used in which the etching rate of InP is greater than that of InGaAs and which does not erode the protective film 611, the first transfer substrate 612, and the adhesive layer 613 (for example, hydrochloric acid, a mixture of hydrochloric acid and phosphoric acid, or a mixture of hydrochloric acid and nitric acid). The thickness of the contact layer 604 is set to a thickness that allows the etching to be stopped at this time.

[0204] The semiconductor thin film 610 is separated from the growth substrate 601 by the complete removal of the sacrificial layer 603. During wet etching, the semiconductor thin film 610 is held on the first transfer substrate 612.

[0205] Figure 55 is a cross-sectional view showing the process of removing the stop layer 602 on the growth substrate 601. In step S612 (Figure 49), the stop layer 602 (InGaAs) on the growth substrate 601 is removed by wet etching. As the etchant, an etchant is used in which the etching rate of InGaAs is greater than that of InP (for example, phosphoric acid, or a mixture of phosphoric acid and hydrogen peroxide).

[0206] The removal of the stop layer 602 smooths the surface of the growth substrate 601 (InP substrate). This makes it possible to reuse the growth substrate 601 as a substrate for epitaxial growth of a semiconductor layer. Figure 58 also shows the semiconductor thin film 610 held on the first transfer substrate 612. The process in step S612 may be performed separately from the process in Figure 49 (steps S601 to S611).

[0207] Subsequently, the semiconductor thin film 610 is bonded to the intermediate substrate (step S606), the first transfer substrate and protective film are removed (step S607), the intermediate sacrificial layer of the intermediate substrate is partially removed by etching (step S608), the semiconductor thin film 610 is selectively separated from the intermediate substrate and bonded to the device substrate (steps S609, S610), and electrodes and the like are formed (step S611). These steps are the same as steps S107 to S112 of Embodiment 1.

[0208] Steps S601 to S608 yield a semiconductor support structure similar to the semiconductor support structure 10 of Embodiment 1 (Figure 10), except that the position of the contact layer 604 is different. Steps S601 to S608 correspond to a method for manufacturing the semiconductor support structure. Steps S601 to S605 correspond to a process for obtaining a plurality of semiconductor thin films 610.

[0209] As described above, in Embodiment 6, the contact layer 604 plays a role in stopping etching when removing the semiconductor thin film 610. Therefore, in addition to the effects of Embodiment 1, the effect of being able to form the semiconductor thin film 610 with fewer steps is obtained. Also, similar to Embodiment 5, the effect of being able to reuse the growth substrate 601 is obtained.

[0210] <Embodiment 7> Figure 56 is a flowchart showing the method for manufacturing a semiconductor device according to Embodiment 7. Figure 57 is a cross-sectional view showing the process of forming each semiconductor layer, including the semiconductor thin film 710, on the growth substrate 701.

[0211] In step S701 (Figure 56), as shown in Figure 57, a stop layer 702, a sacrificial layer 703, a first stop layer 704, a second stop layer 705, a contact layer 706, a lower cladding layer 707, an active layer 708, and an upper cladding layer 709 are sequentially formed on the growth substrate 701 by epitaxial growth. The structure on which each layer 702 to 709 is formed is also referred to as a laminated substrate 700.

[0212] Of these, the contact layer 706, the lower cladding layer 707, the active layer 708, and the upper cladding layer 709 constitute the semiconductor thin film 710. The semiconductor thin film 710 is also referred to as the semiconductor crystal layer or the functional layer. Furthermore, the semiconductor thin film 710 before patterning (Figure 58(A), (B)), which will be described later, is also referred to as the semiconductor layer. The stop layers 704 to 705 are also referred to as predetermined layers.

[0213] The growth substrate 701 is an InP substrate, similar to the growth substrate 101 in Embodiment 1. The stop layer 702 is formed of i-InGaAs, and the sacrificial layer 703 is formed of InP. The first stop layer 704 is formed of i-InGaAs, and the second stop layer 705 is formed of InP. The contact layer 706 is formed of p-InGaAs, the lower cladding layer 707 is formed of p-InP, the active layer 708 is formed of i-InGaAs, and the upper cladding layer 709 is formed of n-InP. In other words, the bottom layer of the semiconductor thin film 710 is the contact layer 706 (p-InGaAs).

[0214] Figures 58(A) and (B) are a cross-sectional view and a plan view showing the process of patterning the semiconductor thin film 710. As shown in Figures 58(A) and (B), in step S702 (Figure 56), the semiconductor thin film 710 is etched along a predetermined separation region to form a grid-like groove G1. Figures 58(A) and (B) show the portion of the semiconductor thin film 710 that has been separated into 4 rows and 4 columns (16 regions).

[0215] The semiconductor thin film 710 is patterned by etching from the upper cladding layer 709 to the first stop layer 704. The etching method is the same as the patterning process (dry etching) of the semiconductor thin film 110 in Embodiment 1. The thickness of the first stop layer 704 is set to a thickness that allows the etching to be stopped at this time. Alternatively, the second stop layer 705 may be patterned by wet etching.

[0216] Figure 59 is a cross-sectional view showing the process of forming a protective film 711 that covers the semiconductor thin film 710. In step S703 (Figure 56), as shown in Figure 59, a protective film 711 is formed that covers the side and top surfaces of the semiconductor thin film 710. The material and method of forming the protective film 711 are the same as those of the protective film 111 in Embodiment 1.

[0217] Figure 60 is a cross-sectional view showing the process of attaching the semiconductor thin film 710 to the first transfer substrate 712. In step S604 (Figure 56), as shown in Figure 60, the protective film 711 on the semiconductor thin film 710 is attached to the adhesive layer 713 provided on the first transfer substrate 712. The first transfer substrate 712 and the adhesive layer 713 are formed in the same manner as the first transfer substrate 112 and adhesive layer 113 of Embodiment 1, respectively.

[0218] Figure 61 is a cross-sectional view showing the process of separating the semiconductor thin film 710 by removing the sacrificial layer 703. As shown in Figure 61, in step S705 (Figure 56), the semiconductor thin film 710 is separated from the growth substrate 701 by removing the sacrificial layer 703 (InP) by wet etching. As the etchant, an etchant is used in which the etching rate of InP is greater than that of InGaAs and which does not erode the protective film 711, the first transfer substrate 712, and the adhesive layer 713 (for example, hydrochloric acid, a mixture of hydrochloric acid and phosphoric acid, or a mixture of hydrochloric acid and nitric acid).

[0219] The semiconductor thin film 710 is separated from the growth substrate 701 by the complete removal of the sacrificial layer 703. During wet etching, the semiconductor thin film 710 is held on the first transfer substrate 712.

[0220] Figure 62 is a cross-sectional view showing the process of removing the first stop layer 704. In step S706 (Figure 56), as shown in Figure 62, the first stop layer 704 (InGaAs) is removed by wet etching. As the etchant, an etchant is used in which the etching rate of InGaAs is greater than that of InP and which does not erode the protective film 711, the first transfer substrate 712, and the adhesive layer 713 (for example, phosphoric acid, or a mixture of phosphoric acid and hydrogen peroxide). In addition to the semiconductor thin film 710 held by the first transfer substrate 712, the growth substrate 701 is also shown in Figure 62.

[0221] Figure 63 is a cross-sectional view showing the steps of removing the second stop layer 705 and removing the stop layer 702 of the growth substrate 701 together. In step S707 (Figure 56), as shown in Figure 63, the second stop layer 705 (InP) of the semiconductor thin film 710 is removed by wet etching. As the etchant, an etchant is used in which the etching rate of InP is greater than the etching rate of InGaAs and which does not erode the protective film 711, the first transfer substrate 712, and the adhesive layer 713 (for example, hydrochloric acid, a mixture of hydrochloric acid and phosphoric acid, or a mixture of hydrochloric acid and nitric acid).

[0222] In addition to step S707, in step S715 (Figure 56), the stop layer 702 (InGaAs) on the growth substrate 701 is removed by wet etching. As the etchant, an etchant is used in which the etching rate of InGaAs is greater than that of InP (for example, phosphoric acid, or a mixture of phosphoric acid and hydrogen peroxide).

[0223] The removal of the stop layer 702 smooths the surface of the growth substrate 701 (InP substrate). This makes it possible to reuse the growth substrate 701 as a substrate for epitaxial growth of semiconductor layers.

[0224] Although steps S706 and S715 are shown side-by-side in the flowchart of Figure 56, they do not necessarily need to be executed in parallel. Furthermore, the process in step S715 may be performed separately from the processes in Figure 56 (steps S701 to S713).

[0225] Subsequently, the semiconductor thin film 710 is bonded to the intermediate substrate (step S708), the first transfer substrate and protective film are removed (step S709), the intermediate sacrificial layer of the intermediate substrate is partially removed by etching (step S710), the semiconductor thin film 710 is selectively separated from the intermediate substrate and bonded to the device substrate (steps S711, S712), and electrodes and the like are formed (step S713). These steps are the same as steps S107 to S112 of Embodiment 1.

[0226] Steps S701 to S710 yield a semiconductor support structure similar to the semiconductor support structure 10 of Embodiment 1 (Figure 10), except that the position of the contact layer 706 is different. Steps S701 to S710 correspond to a method for manufacturing the semiconductor support structure. Steps S701 to S705 correspond to a process for obtaining a plurality of semiconductor thin films 710.

[0227] As described above, in Embodiment 7, in addition to the effects of Embodiment 1, the first stop layer 704 and the second stop layer 705 are sequentially removed by etching, so less residue remains on the underside of the semiconductor thin film 710, and the yield in the bonding process to the device substrate is improved. Also, similar to Embodiments 5 and 6 described above, the growth substrate 701 can be reused.

[0228] <Embodiment 8> Figure 64 is a flowchart showing the method for manufacturing a semiconductor device according to Embodiment 8. Figure 65 is a cross-sectional view showing the process of forming each semiconductor layer, including the semiconductor thin film 810, on the growth substrate 801.

[0229] In step S801 (Figure 64), as shown in Figure 65, a sacrificial layer 802, a first stop layer 803, a second stop layer 804, a lower cladding layer 805, an active layer 806, an upper cladding layer 807, and a contact layer 808 are sequentially formed on the growth substrate 801 by epitaxial growth. The structure in which each layer 802 to 808 is formed on the growth substrate 801 is also referred to as a laminated substrate 800.

[0230] Of these, the lower cladding layer 805, the active layer 806, the upper cladding layer 807, and the contact layer 808 constitute the semiconductor thin film 810. The semiconductor thin film 810 is also referred to as the semiconductor crystal layer or the functional layer. Furthermore, the semiconductor thin film 810 before patterning (Figure 66(A), (B)), which will be described later, is also referred to as the semiconductor layer. The stop layers 803 and 804 are also referred to as predetermined layers.

[0231] The growth substrate 801 is an InP substrate, similar to the growth substrate 101 in Embodiment 1. The sacrificial layer 802 is formed of i-InGaAs, the first stop layer 803 is formed of InP, and the second stop layer 804 is formed of i-InGaAs. The lower cladding layer 805 is formed of n-InP, the active layer 806 is formed of i-InGaAs, the upper cladding layer 807 is formed of p-InP, and the contact layer 808 is formed of p-InGaAs.

[0232] Figures 66(A) and (B) are cross-sectional and plan views showing the process of patterning the semiconductor thin film 810. As shown in Figures 66(A) and (B), in step S802 (Figure 64), the semiconductor thin film 810 is etched along pre-set separation regions to form a grid-like groove G1. Figures 66(A) and (B) show the portion of the semiconductor thin film 810 separated into 4 rows and 4 columns (16 regions).

[0233] The semiconductor thin film 810 is patterned by etching from the upper cladding layer 807 to the first stop layer 803. The etching method is the same as the patterning process (dry etching) of the semiconductor thin film 110 in Embodiment 1. The thickness of the first stop layer 803 is set to a thickness that allows the etching to be stopped at this time. Alternatively, the lower cladding layer 805 may be patterned by wet etching.

[0234] Figure 67 is a cross-sectional view showing the process of forming a protective film 811 that covers the semiconductor thin film 810. In step S803 (Figure 64), as shown in Figure 67, a protective film 811 is formed that covers the side and top surfaces of the semiconductor thin film 810. The material and method of forming the protective film 811 are the same as those of the protective film 111 in Embodiment 1.

[0235] Figure 68 is a cross-sectional view showing the process of attaching the semiconductor thin film 810 to the first transfer substrate 812. In step S804 (Figure 64), as shown in Figure 68, the protective film 811 on the semiconductor thin film 810 is attached to the adhesive layer 813 provided on the first transfer substrate 812. The first transfer substrate 812 and the adhesive layer 813 are formed in the same manner as the first transfer substrate 112 and adhesive layer 113 of Embodiment 1, respectively.

[0236] Figure 69 is a cross-sectional view showing the process of separating the semiconductor thin film 810 by removing the sacrificial layer 802. As shown in Figure 69, in step S805 (Figure 64), the semiconductor thin film 810 is separated from the growth substrate 801 by removing the sacrificial layer 802 (InGaAs) by wet etching. As the etchant, an etchant is used in which the etching rate of InGaAs is greater than that of InP and which does not erode the protective film 811, the first transfer substrate 812, and the adhesive layer 813 (for example, phosphoric acid, or a mixture of phosphoric acid and hydrogen peroxide). The first stop layer 803 can stop the etching.

[0237] The semiconductor thin film 810 is separated from the growth substrate 801 by the complete removal of the sacrificial layer 802. During wet etching, the semiconductor thin film 810 is held on the first transfer substrate 812. In addition, the removal of the sacrificial layer 802 smooths the surface of the growth substrate 801, making it reusable.

[0238] Figure 70(A) is a cross-sectional view showing the process of removing the first stop layer 803. In step S806 (Figure 64), the first stop layer 803 (InP) is removed by wet etching. As the etchant, an etchant is used that has an etching rate for InP greater than that of InGaAs and does not erode the protective film 811, the first transfer substrate 812, and the adhesive layer 813 (e.g., hydrochloric acid, a mixture of hydrochloric acid and phosphoric acid, or a mixture of hydrochloric acid and nitric acid).

[0239] Figure 70(B) is a cross-sectional view showing the process of removing the second stop layer 804. In step S807 (Figure 64), the second stop layer 804 (InGaAs) is removed by wet etching. As the etchant, an etchant is used in which the etching rate of InGaAs is greater than that of InP and which does not erode the protective film 811, the first transfer substrate 812, and the adhesive layer 813 (for example, phosphoric acid, or a mixture of phosphoric acid and hydrogen peroxide).

[0240] Subsequently, the semiconductor thin film 810 is bonded to the intermediate substrate (step S808), the first transfer substrate and protective film are removed (step S809), the intermediate sacrificial layer of the intermediate substrate is partially removed by etching (step S810), the semiconductor thin film 810 is selectively separated from the intermediate substrate and bonded to the device substrate (steps S811, S812), and electrodes and the like are formed (step S813). These steps are the same as steps S107 to S112 of Embodiment 1.

[0241] Steps S801 to S810 provide a semiconductor support structure similar to the semiconductor support structure 10 of Embodiment 1 (Figure 10). Steps S801 to S810 correspond to a method for manufacturing the semiconductor support structure. Steps S801 to S805 correspond to a process for obtaining a plurality of semiconductor thin films 810.

[0242] As described above, in Embodiment 8, in addition to the effects of Embodiment 1, the first stop layer 803 and the second stop layer 804 are sequentially removed by etching, so less residue remains on the underside of the semiconductor thin film 810, and the yield in the bonding process to the device substrate is improved. Furthermore, by removing the sacrificial layer 802 on the growth substrate 801, the growth substrate 801 can be reused.

[0243] <Embodiment 9> Figure 71 is a flowchart showing the method for manufacturing a semiconductor device according to Embodiment 9. Figure 72 is a cross-sectional view showing the process of forming each semiconductor layer, including the semiconductor thin film 910, on the growth substrate 901.

[0244] In step S901 (Figure 71), as shown in Figure 72, a sacrificial layer 902, a stop layer 903, a contact layer 904, a lower cladding layer 905, an active layer 906, and an upper cladding layer 907 are sequentially formed on the growth substrate 901 by epitaxial growth. The structure in which each layer 902 to 907 is formed on the growth substrate 901 is also referred to as a laminated substrate 900.

[0245] Of these, the contact layer 904, the lower cladding layer 905, the active layer 906, and the upper cladding layer 907 constitute the semiconductor thin film 910. The semiconductor thin film 910 is also referred to as the semiconductor crystal layer or the functional layer. Furthermore, the semiconductor thin film 910 before patterning (Figure 73(A), (B)), which will be described later, is also referred to as the semiconductor layer. The stop layer 903 is also referred to as the predetermined layer.

[0246] The growth substrate 901 is an InP substrate, similar to the growth substrate 101 in Embodiment 1. The stop layer 903 is formed of InP. The contact layer 904 is formed of p-InGaAs, the lower cladding layer 905 is formed of p-InP, the active layer 906 is formed of i-InGaAs, and the upper cladding layer 907 is formed of n-InP. In other words, the bottom layer of the semiconductor thin film 910 is the contact layer 904 (p-InGaAs).

[0247] Figures 73(A) and (B) are a cross-sectional view and a plan view showing the process of patterning the semiconductor thin film 910. As shown in Figures 73(A) and (B), in step S902 (Figure 71), the semiconductor thin film 910 is etched along a predetermined separation region to form a grid-like groove G1. Figures 73(A) and (B) show the portion of the semiconductor thin film 910 that has been separated into 4 rows and 4 columns (16 regions).

[0248] The semiconductor thin film 910 is patterned by etching from the upper cladding layer 907 to the stop layer 903. The etching method is the same as the patterning process (dry etching) of the semiconductor thin film 110 in Embodiment 1. The thickness of the stop layer 903 is set to a thickness that allows the etching to be stopped at this time.

[0249] Figure 74 is a cross-sectional view showing the process of forming a protective film 911 that covers the semiconductor thin film 910. In step S903 (Figure 71), as shown in Figure 74, a protective film 911 is formed that covers the side and top surfaces of the semiconductor thin film 910. The material and method of forming the protective film 911 are the same as those of the protective film 111 in Embodiment 1.

[0250] Figure 75 is a cross-sectional view showing the process of attaching the semiconductor thin film 910 to the first transfer substrate 912. In step S904 (Figure 71), as shown in Figure 75, the protective film 911 on the semiconductor thin film 910 is attached to the adhesive layer 913 provided on the first transfer substrate 912. The first transfer substrate 912 and the adhesive layer 913 are formed in the same manner as the first transfer substrate 112 and adhesive layer 113 of Embodiment 1, respectively.

[0251] Figure 76 is a cross-sectional view showing the process of separating the semiconductor thin film 910 by removing the sacrificial layer 902. As shown in Figure 76, in step S905 (Figure 71), the semiconductor thin film 910 is separated from the growth substrate 901 by removing the sacrificial layer 902 (InGaAs) by wet etching. As the etchant, an etchant is used in which the etching rate of InGaAs is greater than that of InP and does not erode the protective film 911, the first transfer substrate 912, and the adhesive layer 913 (for example, phosphoric acid, or a mixture of phosphoric acid and hydrogen peroxide). The thickness of the stop layer 903 is set to a thickness that allows etching to be stopped at this time.

[0252] The semiconductor thin film 910 is separated from the growth substrate 901 by the complete removal of the sacrificial layer 902. During wet etching, the semiconductor thin film 910 is held on the first transfer substrate 912. In addition, the removal of the sacrificial layer 902 smooths the surface of the growth substrate 901, making it reusable.

[0253] Figure 77 is a cross-sectional view showing the process of removing the stop layer 903. In step S906 (Figure 71), the stop layer 903 (InP) is removed by wet etching. As the etchant, an etchant is used in which the etching rate of InP is greater than that of InGaAs and which does not erode the protective film 911, the first transfer substrate 912, and the adhesive layer 913 (for example, hydrochloric acid, a mixture of hydrochloric acid and phosphoric acid, or a mixture of hydrochloric acid and nitric acid). Figure 77 also shows the growth substrate 901 from which the sacrificial layer 902 has been removed.

[0254] Subsequently, the semiconductor thin film 910 is bonded to the intermediate substrate (step S907), the first transfer substrate and protective film are removed (step S908), the intermediate sacrificial layer of the intermediate substrate is partially removed by etching (step S909), the semiconductor thin film 910 is selectively separated from the intermediate substrate and bonded to the device substrate (steps S910, S911), and electrodes and the like are formed (step S912). These steps are the same as steps S107 to S112 of Embodiment 1.

[0255] Steps S901 to S909 yield a semiconductor support structure similar to the semiconductor support structure 10 of Embodiment 1 (Figure 10) (except for the position of the contact layer 904). Steps S901 to S909 correspond to a method for manufacturing the semiconductor support structure. Steps S901 to S905 correspond to a process for obtaining a plurality of semiconductor thin films 910.

[0256] As described above, in Embodiment 9, in addition to the effects of Embodiment 1, a sacrificial layer 902 is formed on the growth substrate 901, which provides the effect of enabling the reuse of the growth substrate 901.

[0257] <Embodiment 10> Figure 78 is a cross-sectional view showing the process of forming each semiconductor layer, including the semiconductor thin film 1010, on the growth substrate 1001 in the semiconductor device manufacturing method of Embodiment 10. Note that the flowchart for Embodiment 10 is omitted.

[0258] As shown in Figure 78, a buffer layer 1002, a contact layer 1003, a lower cladding layer 1004, an active layer 1005, and an upper cladding layer 1006 are sequentially formed on the growth substrate 1001 by epitaxial growth. The substrate 1001 with each of the layers 1002 to 1006 formed is also referred to as a laminated substrate 1000.

[0259] Of these, the contact layer 1003, the lower cladding layer 1004, the active layer 1005, and the upper cladding layer 1006 constitute the semiconductor thin film 1010. The semiconductor thin film 1010 is also referred to as the semiconductor crystal layer or functional layer. Furthermore, the semiconductor thin film 1010 before patterning (Figure 79 (A), (B)), which will be described later, is also referred to as the semiconductor layer.

[0260] The growth substrate 1001 is an InP substrate, similar to the growth substrate 101 of Embodiment 1. The buffer layer 1002 is formed of InP. The contact layer 1003 is formed of p-InGaAs, the lower cladding layer 1004 is formed of p-InP, the active layer 1005 is formed of i-InGaAs, and the upper cladding layer 1006 is formed of n-InP. In other words, the bottom layer of the semiconductor thin film 1010 is the contact layer 1003.

[0261] Figures 79(A) and (B) are a cross-sectional view and a plan view showing the process of patterning the semiconductor thin film 1010. As shown in Figures 79(A) and (B), the semiconductor thin film 1010 is etched along pre-set separation regions to form a grid-like groove G1. Figures 79(A) and (B) show a portion of the semiconductor thin film 1010 separated into 4 rows and 4 columns (16 regions).

[0262] The semiconductor thin film 1010 is patterned by etching that reaches from the upper cladding layer 1006 to the buffer layer 1002. The etching method is the same as the patterning process (dry etching) of the semiconductor thin film 110 in Embodiment 1. The thickness of the buffer layer 1002 is set to a thickness that allows the etching to be stopped at this time.

[0263] Figure 80 is a cross-sectional view showing the process of forming a protective film 1011 that covers the semiconductor thin film 1010. As shown in Figure 80, a protective film 1011 is formed that covers the side and top surfaces of the semiconductor thin film 1010. The material and method of forming the protective film 1011 are the same as those of the protective film 111 in Embodiment 1.

[0264] Figure 81 is a cross-sectional view showing the process of attaching the semiconductor thin film 1010 to the first transfer substrate 1012. As shown in Figure 81, the protective film 1011 on the semiconductor thin film 1010 is attached to the adhesive layer 1013 provided on the first transfer substrate 1012. The first transfer substrate 1012 and the adhesive layer 1013 are formed in the same manner as the first transfer substrate 112 and adhesive layer 113 of Embodiment 1, respectively.

[0265] Figure 82 is a cross-sectional view showing the semiconductor thin film 1010 separated by the removal of the growth substrate 1001 and the buffer layer 1002. As shown in Figure 82, the semiconductor thin film 1010 is separated from the growth substrate 1001 by wet etching the growth substrate 1001 and the buffer layer 102 (both InP) from the bottom surface. As the etchant, an etchant is used in which the etching rate of InP is greater than the etching rate of InGaAs and which does not erode the protective film 1011, the first transfer substrate 1012, and the adhesive layer 1013 (for example, hydrochloric acid, a mixture of hydrochloric acid and phosphoric acid, or a mixture of hydrochloric acid and nitric acid).

[0266] The semiconductor thin film 1010 is separated from the growth substrate 1001 by the complete removal of the growth substrate 1001 and the buffer layer 1002. During wet etching, the semiconductor thin film 1010 is held on the first transfer substrate 1012. During wet etching, the contact layer 1003 (p-InGaAs), which is the bottom layer of the semiconductor thin film 1010, acts as a stop layer.

[0267] Subsequently, the semiconductor thin film 1010 is bonded to the intermediate substrate, the first transfer substrate and protective film are removed, the intermediate sacrificial layer of the intermediate substrate is partially removed by etching, and then the semiconductor thin film 1010 is selectively separated from the intermediate substrate and bonded to the device substrate to form electrodes, etc. These steps are the same as steps S107 to S112 of Embodiment 1.

[0268] As described above, in Embodiment 10, in addition to the effects of Embodiment 1, the contact layer 1003 plays the role of a stop layer, thus providing the advantage of being able to form the semiconductor thin film 1010 with fewer steps.

[0269] <Embodiment 11> Figure 83 is a cross-sectional view showing the process of forming each semiconductor layer, including the semiconductor thin film 1110, on the growth substrate 1101 in the semiconductor device manufacturing method of Embodiment 11. The flowchart for Embodiment 11 is omitted.

[0270] As shown in Figure 83, a first stop layer 1102, a second stop layer 1103, a contact layer 1104, a lower cladding layer 1105, an active layer 1106, and an upper cladding layer 1107 are sequentially formed on the growth substrate 1101 by epitaxial growth. The substrate 1101 with each of the layers 1102 to 1107 formed is also referred to as a laminated substrate 1100.

[0271] Of these, the contact layer 1104, the lower cladding layer 1105, the active layer 1106, and the upper cladding layer 1107 constitute the semiconductor thin film 1110. The semiconductor thin film 1110 is also referred to as the semiconductor crystal layer or functional layer. Furthermore, the semiconductor thin film 1110 before patterning (Figure 84(A), (B)), which will be described later, is also referred to as the semiconductor layer.

[0272] The growth substrate 1101 is an InP substrate, similar to the growth substrate 101 in Embodiment 1. The first stop layer 1102 is formed of i-InGaAs, and the second stop layer 1103 is formed of InP. The contact layer 1104 is formed of p-InGaAs, the lower cladding layer 1105 is formed of p-InP, the active layer 1106 is formed of i-InGaAs, and the upper cladding layer 1107 is formed of n-InP. In other words, the bottom layer of the semiconductor thin film 1110 is the contact layer 1104 (p-InGaAs).

[0273] Figures 84(A) and (B) are a cross-sectional view and a plan view showing the process of patterning the semiconductor thin film 1110. As shown in Figures 84(A) and (B), the semiconductor thin film 1110 is etched along pre-set separation regions to form a grid-like groove G1. Figures 84(A) and (B) show a portion of the semiconductor thin film 1110 separated into 4 rows and 4 columns (16 regions).

[0274] The semiconductor thin film 1110 is patterned by etching that extends from the upper cladding layer 1107 to the second stop layer 1103. The etching method is the same as the patterning process (dry etching) of the semiconductor thin film 110 in Embodiment 1. The thickness of the second stop layer 1103 is set to a thickness that allows the etching to be stopped at this stage.

[0275] Figure 85 is a cross-sectional view showing the process of forming a protective film 1111 that covers the semiconductor thin film 1110. As shown in Figure 85, a protective film 1111 is formed that covers the side and top surfaces of the semiconductor thin film 1110. The material and method of forming the protective film 1111 are the same as those of the protective film 111 in Embodiment 1.

[0276] Figure 86 is a cross-sectional view showing the process of attaching the semiconductor thin film 1110 to the first transfer substrate 1112. As shown in Figure 86, the protective film 1111 on the semiconductor thin film 1110 is attached to the adhesive layer 1113 provided on the first transfer substrate 1112. The first transfer substrate 1112 and the adhesive layer 1113 are formed in the same manner as the first transfer substrate 112 and adhesive layer 113 of Embodiment 1, respectively.

[0277] Figure 87 is a cross-sectional view showing the state after the semiconductor thin film 1110 has been separated by the removal of the growth substrate 1101. As shown in Figure 87, the semiconductor thin film 1110 is separated from the growth substrate 1101 (InP substrate) by wet etching. As the etchant, an etchant is used in which the etching rate of InP is greater than the etching rate of InGaAs and which does not erode the protective film 1111, the first transfer substrate 1112, and the adhesive layer 113 (for example, hydrochloric acid, a mixture of hydrochloric acid and phosphoric acid, or a mixture of hydrochloric acid and nitric acid). The thickness of the first stop layer 1102 is set to a thickness that allows the etching to be stopped at this time.

[0278] Figure 88 is a cross-sectional view showing the process of removing the first stop layer 1102. As shown in Figure 88, the first stop layer 1102 (InGaAs) is removed by wet etching. As the etchant, an etchant is used in which the etching rate of InGaAs is greater than that of InP and which does not erode the protective film 1111, the first transfer substrate 1112, and the adhesive layer 113 (for example, phosphoric acid, or a mixture of phosphoric acid and hydrogen peroxide).

[0279] Figure 89 is a cross-sectional view showing the process of removing the second stop layer 1103. As shown in Figure 89, the second stop layer 1103 (InP) is removed by wet etching. As the etchant, an etchant is used in which the etching rate of InP is greater than that of InGaAs and which does not erode the protective film 1111, the first transfer substrate 1112, and the adhesive layer 113 (for example, hydrochloric acid, a mixture of hydrochloric acid and phosphoric acid, or a mixture of hydrochloric acid and nitric acid).

[0280] The growth substrate 1101 generally has a thickness of 100 μm or more, and is prone to variations in etching depth. However, by stopping the etching to remove the growth substrate 1101 at the first stop layer 1102 (Figure 87), and stopping the etching to remove the first stop layer 1102 at the second stop layer 1103 (Figure 88), the variation in etching depth can be suppressed to 10 nm or less, and the smoothness of the lower surface of the semiconductor thin film 1110 can be improved.

[0281] Subsequently, the semiconductor thin film 1110 is bonded to the intermediate substrate, the first transfer substrate and protective film are removed, the intermediate sacrificial layer of the intermediate substrate is partially removed by etching, and then the semiconductor thin film 1110 is selectively separated from the intermediate substrate and bonded to the device substrate to form electrodes, etc. These steps are the same as steps S107 to S112 of Embodiment 1.

[0282] As described above, in Embodiment 11, in addition to the effects of Embodiment 1, the first stop layer 1102 and the second stop layer 1103 are sequentially removed by etching, thereby reducing variations in etching depth during the removal process of the growth substrate 1101 and improving the smoothness of the lower surface of the semiconductor thin film 1110.

[0283] <Embodiment 12> Figure 90 is a flowchart showing the method for manufacturing a semiconductor device according to Embodiment 12. Figure 91 is a cross-sectional view showing the process of forming each semiconductor layer, including the semiconductor thin film 1210, on the growth substrate 1201.

[0284] In step S1201 (Figure 90), as shown in Figure 91, a buffer layer 1202, a stop layer 1203, a lower cladding layer 1204, an active layer 1205, an upper cladding layer 1206, and a contact layer 1207 are sequentially formed on the growth substrate 1201 by epitaxial growth. The substrate 1201 with each of the layers 1202 to 1207 formed on it is also called a laminated substrate 1200.

[0285] Of these, the lower cladding layer 1204, the active layer 1205, the upper cladding layer 1206, and the contact layer 1207 constitute the semiconductor thin film 1210. The semiconductor thin film 1210 is also referred to as the semiconductor crystal layer or functional layer. Furthermore, the semiconductor thin film 1210 before patterning (Figure 94(A), (B)), which will be described later, is also referred to as the semiconductor layer. The stop layer 1203 is also referred to as the predetermined layer.

[0286] The growth substrate 1201 is an InP substrate, similar to the growth substrate 101 in Embodiment 1. The buffer layer 1202 is made of InP, and the stop layer 1203 is made of i-InGaAs. The lower cladding layer 1204 is made of n-InP, the active layer 1205 is made of i-InGaAs, the upper cladding layer 1206 is made of p-InP, and the contact layer 1207 is made of p-InGaAs.

[0287] Figure 92 is a cross-sectional view showing the process of attaching the semiconductor thin film 1210 to the first transfer substrate 1212. In step S1202 (Figure 90), as shown in Figure 92, the upper surface of the semiconductor thin film 1210 is attached to the adhesive layer 1213 provided on the first transfer substrate 1212. The first transfer substrate 1212 and the adhesive layer 1213 are formed in the same manner as the first transfer substrate 112 and the adhesive layer 113 of Embodiment 1, respectively.

[0288] Figure 93 is a cross-sectional view showing the process of separating the semiconductor thin film 1210 by removing the growth substrate 1201 and the buffer layer 1202. In step S1203 (Figure 90), as shown in Figure 93, the semiconductor thin film 1210 is separated from the growth substrate 1201 by wet etching the growth substrate 1201 and the buffer layer 1202 (both InP) from the bottom surface. As the etchant, an etchant is used in which the etching rate of InP is greater than the etching rate of InGaAs and which does not erode the first transfer substrate 1212 and the adhesive layer 1213 (for example, hydrochloric acid, a mixture of hydrochloric acid and phosphoric acid, or a mixture of hydrochloric acid and nitric acid). The thickness of the stop layer 1203 is set to a thickness that allows the etching at this time to be stopped.

[0289] Figures 94(A) and (B) are a cross-sectional view and a plan view showing the process of patterning the semiconductor thin film 1210. In step S1204 (Figure 90), as shown in Figures 94(A) and (B), the semiconductor thin film 1210 is etched along predetermined separation regions to form a grid-like groove G1. Figures 94(A) and (B) show the portion of the semiconductor thin film 1210 separated into 4 rows and 4 columns (16 regions).

[0290] The semiconductor thin film 1210 is patterned by etching that reaches from the stop layer 1203 to the adhesive layer 1213. Dry etching is used as the etching method. The etching direction for dry etching is the vertical direction, that is, the direction perpendicular to the upper surface of the growth substrate 1201 (the direction perpendicular to the surface orientation 010 or 001).

[0291] Figure 95 is a cross-sectional view showing the process of forming a protective film 1215 that covers the semiconductor thin film 1210. In step S1205 (Figure 90), as shown in Figure 95, a protective film 1215 is formed that covers the side and bottom surfaces of the semiconductor thin film 1210. The material and method of forming the protective film 1215 are the same as those of the protective film 111 in Embodiment 1.

[0292] Figure 96 is a cross-sectional view showing the process of removing a portion (bottom) of the protective film 1215. In step S1206 (Figure 90), as shown in Figure 96, the bottom of the protective film 1215 is removed, exposing the lower surface of the stop layer 1203.

[0293] Removal of the bottom of the protective film 1215 is done because the protective film 1215 is SiO ２ In this case, wet etching using hydrofluoric acid is performed, and the protective film 1215 is Al ２ O ３ In that case, wet etching using phosphoric acid or hydrofluoric acid is performed, and if the protective film 1215 is an organic material, O ２ This can be done using plasma-based dry etching.

[0294] Figure 97 is a cross-sectional view showing the process of removing the stop layer 1203 of the semiconductor thin film 1210. In step S1207 (Figure 90), the stop layer 1203 (InGaAs) of the semiconductor thin film 1210 is removed by wet etching. As the etchant, an etchant is used in which the etching rate of InGaAs is greater than that of InP and does not erode the protective film 1215, the first transfer substrate 1212, and the adhesive layer 1213 (for example, phosphoric acid, or a mixture of phosphoric acid and hydrogen peroxide).

[0295] Figure 98 is a cross-sectional view showing the process of removing the protective film 1215 from the semiconductor thin film 1210. In step S1208 (Figure 90), the protective film 1215 covering the semiconductor thin film 1210 is removed by etching. The removal of the protective film 1215 is performed by wet etching or dry etching using the same etchant as in step S1206 (removal of the bottom of the protective film 1215).

[0296] Subsequently, the semiconductor thin film 1210 is bonded to the intermediate substrate (step S1209), the first transfer substrate is removed (step S1210), the intermediate sacrificial layer of the intermediate substrate is partially removed by etching (step S1215), the semiconductor thin film 1210 is selectively separated from the intermediate substrate and bonded to the device substrate (steps S1212, S1213), and electrodes and the like are formed (step S1214). These steps are the same as steps S107 to S112 of Embodiment 1.

[0297] Steps S1201 to S1215 yield a semiconductor support structure similar to the semiconductor support structure 10 of Embodiment 1 (Figure 10). Steps S1201 to S1215 correspond to a method for manufacturing the semiconductor support structure. Steps S1201 to S1204 correspond to a process for obtaining a plurality of semiconductor thin films 1210.

[0298] As described above, in Embodiment 12, since the semiconductor thin film 1210 is patterned after the growth substrate 1201 is removed, there is no need to stop etching midway through the epitaxial layer (including the semiconductor thin film 1210, buffer layer 1202, and stop layer 1203) on the growth substrate 1201. Therefore, the number of stop layers can be reduced, and the thickness can be made thinner.

[0299] <Embodiment 13> Figure 99 is a cross-sectional view showing the process of forming each semiconductor layer, including the semiconductor thin film 1310, on the growth substrate 1301 in the semiconductor device manufacturing method of Embodiment 13. The flowchart for Embodiment 13 is omitted.

[0300] As shown in Figure 99, a buffer layer 1302, a first stop layer 1303, a second stop layer 1304, a third stop layer 1305, a lower cladding layer 1306, an active layer 1307, an upper cladding layer 1308, and a contact layer 1309 are sequentially formed on the growth substrate 1301 by epitaxial growth. The substrate 1301 with each of the layers 1302 to 1309 formed on it is also called a laminated substrate 1300.

[0301] Of these, the lower cladding layer 1306, the active layer 1307, the upper cladding layer 1308, and the contact layer 1309 constitute the semiconductor thin film 1310. The semiconductor thin film 1310 is also referred to as the semiconductor crystal layer or the functional layer. Furthermore, the semiconductor thin film 1310 before patterning (Figures 102(A) and (B)), which will be described later, is also referred to as the semiconductor layer. The first stop layer 1303 is also referred to as the predetermined layer.

[0302] The growth substrate 1301 is an InP substrate, similar to the growth substrate 101 of Embodiment 1. The buffer layer 1302 is made of InP. The first stop layer 1303 is made of i-InGaAs, the second stop layer 1304 is made of i-InP, and the third stop layer 1305 is made of i-InGaAs. The lower cladding layer 1306 is made of n-InP, the active layer 1307 is made of i-InGaAs, the upper cladding layer 1308 is made of p-InP, and the contact layer 1309 is made of p-InGaAs.

[0303] Figure 100 is a cross-sectional view showing the process of attaching the semiconductor thin film 1310 to the first transfer substrate 1312. As shown in Figure 100, the upper surface of the semiconductor thin film 1310 is attached to the adhesive layer 1313 provided on the first transfer substrate 1312. The first transfer substrate 1312 and the adhesive layer 1313 are formed in the same manner as the first transfer substrate 112 and the adhesive layer 113 of Embodiment 1, respectively.

[0304] Figure 101 is a cross-sectional view showing the process of separating the semiconductor thin film 1310 by removing the growth substrate 1301 and the buffer layer 1302. As shown in Figure 101, the semiconductor thin film 1310 is separated from the growth substrate 1301 by removing the growth substrate 1301 and the buffer layer 1302 (both made of InP) by wet etching. As the etchant, an etchant is used in which the etching rate of InP is greater than the etching rate of InGaAs and which does not erode the first transfer substrate 1312 and the adhesive layer 1313 (for example, hydrochloric acid, a mixture of hydrochloric acid and phosphoric acid, or a mixture of hydrochloric acid and nitric acid). The thickness of the first stop layer 1303 is set to a thickness that allows the etching to be stopped at this time.

[0305] Figures 102(A) and (B) are a cross-sectional view and a plan view showing the process of patterning the semiconductor thin film 1310. As shown in Figures 102(A) and (B), the semiconductor thin film 1310 is etched along pre-set separation regions to form a grid-like groove G1. Figures 102(A) and (B) show portions of the semiconductor thin film 1310 separated into 4 rows and 4 columns (16 regions).

[0306] The semiconductor thin film 1310 is patterned by etching that reaches from the first stop layer 1303 to the adhesive layer 1313. The etching method is the same as the patterning process for the semiconductor thin film 1210 in Embodiment 12.

[0307] Figure 103 is a cross-sectional view showing the process of forming a protective film 1315 that covers the semiconductor thin film 1310. As shown in Figure 103, a protective film 1315 is formed that covers the side and bottom surfaces of the semiconductor thin film 1310. The material and method of forming the protective film 1315 are the same as those of the protective film 111 in Embodiment 1.

[0308] Figure 104 is a cross-sectional view showing the process of removing a portion (bottom) of the protective film 1315. As shown in Figure 104, the bottom of the protective film 1315 is removed to expose the lower surface of the first stop layer 1203. The removal of the bottom of the protective film 1315 can be carried out in the same manner as the removal of the bottom of the protective film 1215 in Embodiment 12.

[0309] Figure 105 is a cross-sectional view showing the process of removing the first stop layer 1303 of the semiconductor thin film 1310. The first stop layer 1303 (InGaAs) of the semiconductor thin film 1310 is removed by wet etching. As the etchant, an etchant is used in which the etching rate of InGaAs is greater than that of InP and which does not erode the protective film 1315, the first transfer substrate 1312, and the adhesive layer 1313 (for example, phosphoric acid, or a mixture of phosphoric acid and hydrogen peroxide).

[0310] Figure 106 is a cross-sectional view showing the process of removing the second stop layer 1304 of the semiconductor thin film 1310. The second stop layer 1304 (InP) of the semiconductor thin film 1310 is removed by wet etching. As the etchant, an etchant is used in which the etching rate of InP is greater than that of InGaAs and which does not erode the protective film 1315, the first transfer substrate 1312, and the adhesive layer 1313 (for example, hydrochloric acid, a mixture of hydrochloric acid and phosphoric acid, or a mixture of hydrochloric acid and nitric acid).

[0311] Figure 107 is a cross-sectional view showing the process of removing the third stop layer 1305 of the semiconductor thin film 1310. The third stop layer 1305 (InP) of the semiconductor thin film 1310 is removed by wet etching. The same etchant used in the removal process for the first stop layer 1303 is used as the etchant.

[0312] Figure 108 is a cross-sectional view showing the process of removing the protective film 1315 from the semiconductor thin film 1310. In step S1208 (Figure 90), the protective film 1315 covering the semiconductor thin film 1310 is removed by etching. The removal of the protective film 1315 is performed by wet etching or dry etching using the same etchant as in the process of removing the bottom of the protective film 1315.

[0313] Subsequently, the semiconductor thin film 1310 is bonded to the intermediate substrate, the first transfer substrate is removed, the intermediate sacrificial layer of the intermediate substrate is partially removed by etching, and then the semiconductor thin film 1310 is selectively separated from the intermediate substrate and bonded to the device substrate to form electrodes, etc. These steps are the same as steps S107 to S112 of Embodiment 1.

[0314] As described above, in Embodiment 13, since the three stop layers 1303, 1304, and 1305 are sequentially removed by etching, less residue remains on the underside of the semiconductor thin film 1310. Therefore, in addition to the effects of Embodiment 12, the yield in the bonding process to the device substrate is improved.

[0315] <Embodiment 14> Figure 109 is a cross-sectional view showing the process of forming each semiconductor layer, including the semiconductor thin film 1410, on a growth substrate 1401 in the semiconductor device manufacturing method of Embodiment 14. The flowchart for Embodiment 14 is omitted.

[0316] As shown in Figure 109, a buffer layer 1402, a contact layer 1403, a lower cladding layer 1404, an active layer 1405, and an upper cladding layer 1406 are sequentially formed on the growth substrate 1401 by epitaxial growth. The substrate 1401 with each of the layers 1402 to 1406 formed on it is also called a laminated substrate 1400.

[0317] Of these, the contact layer 1403, the lower cladding layer 1404, the active layer 1405, and the upper cladding layer 1406 constitute the semiconductor thin film 1410. The semiconductor thin film 1410 is also referred to as the semiconductor crystal layer or functional layer. Furthermore, the semiconductor thin film 1410 before patterning (Figures 112(A) and (B)), which will be described later, is also referred to as the semiconductor layer.

[0318] The growth substrate 1401 is an InP substrate, similar to the growth substrate 101 in Embodiment 1. The buffer layer 1402 is formed of InP. The contact layer 1403 is formed of p-InGaAs, the lower cladding layer 1404 is formed of p-InP, the active layer 1405 is formed of i-InGaAs, and the upper cladding layer 1406 is formed of n-InP. In other words, the bottom layer of the semiconductor thin film 1410 is the contact layer 1403 (p-InGaAs).

[0319] Figure 110 is a cross-sectional view showing the process of attaching the upper surface of the semiconductor thin film 1410 to the first transfer substrate 1412. As shown in Figure 110, the semiconductor thin film 1410 is attached to the adhesive layer 1413 provided on the first transfer substrate 1412. The first transfer substrate 1412 and the adhesive layer 1413 are formed in the same manner as the first transfer substrate 112 and adhesive layer 113 of Embodiment 1, respectively.

[0320] Figure 111 is a cross-sectional view showing the process of separating the semiconductor thin film 1410 by removing the growth substrate 1401 and the buffer layer 1402. As shown in Figure 111, the semiconductor thin film 1410 is separated from the growth substrate 1401 by wet etching the growth substrate 1401 and the buffer layer 1402 (both InP) from the bottom surface. As the etchant, an etchant is used in which the etching rate of InP is greater than the etching rate of InGaAs and which does not erode the first transfer substrate 1412 and the adhesive layer 1413 (for example, hydrochloric acid, a mixture of hydrochloric acid and phosphoric acid, or a mixture of hydrochloric acid and nitric acid). In wet etching, the contact layer 1403 acts as a stopper layer.

[0321] Figures 112(A) and (B) are cross-sectional and plan views showing the process of patterning the semiconductor thin film 1410. As shown in Figures 112(A) and (B), the semiconductor thin film 1410 is etched along pre-set separation regions to form a grid-like groove G1. Figures 112(A) and (B) show portions of the semiconductor thin film 1410 separated into 4 rows and 4 columns (16 regions).

[0322] The semiconductor thin film 1410 is patterned by etching that reaches from the contact layer 1403 to the adhesive layer 1413. The etching method is the same as the patterning process for the semiconductor thin film 1210 in Embodiment 12.

[0323] Subsequently, the semiconductor thin film 1410 is bonded to the intermediate substrate, the first transfer substrate and protective film are removed, the intermediate sacrificial layer of the intermediate substrate is partially removed by etching, and then the semiconductor thin film 1410 is selectively separated from the intermediate substrate and bonded to the device substrate to form electrodes, etc. These steps are the same as steps S107 to S112 of Embodiment 1.

[0324] As described above, in Embodiment 14, in addition to the effects of Embodiment 1, a protective film is not formed to cover the semiconductor thin film 1410, so a semiconductor device can be formed with fewer steps.

[0325] <Embodiment 15> Figure 113 is a cross-sectional view showing the process of forming each semiconductor layer, including the semiconductor thin film 1510, on a growth substrate 1501 in the semiconductor device manufacturing method of Embodiment 15. The flowchart for Embodiment 15 is omitted.

[0326] As shown in Figure 113, a first stop layer 1502, a second stop layer 1503, a contact layer 1504, a lower cladding layer 1505, an active layer 1506, and an upper cladding layer 1507 are sequentially formed on the growth substrate 1501 by epitaxial growth. The substrate 1501 with each of the layers 1502 to 1507 formed on it is also referred to as a laminated substrate 1500.

[0327] Of these, the contact layer 1504, the lower cladding layer 1505, the active layer 1506, and the upper cladding layer 1507 constitute the semiconductor thin film 1510. The semiconductor thin film 1510 is also referred to as the semiconductor crystal layer or the functional layer. Furthermore, the semiconductor thin film 1510 before patterning (Figures 116(A) and (B)), which will be described later, is also referred to as the semiconductor layer. The stop layers 1502 and 1503 are also referred to as predetermined layers.

[0328] The growth substrate 1501 is an InP substrate, similar to the growth substrate 101 in Embodiment 1. The first stop layer 1502 is formed of i-InGaAs, and the second stop layer 1503 is formed of InP. The contact layer 1504 is formed of p-InGaAs, the lower cladding layer 1505 is formed of p-InP, the active layer 1506 is formed of i-InGaAs, and the upper cladding layer 1507 is formed of n-InP. In other words, the bottom layer of the semiconductor thin film 1510 is the contact layer 1504 (p-InGaAs).

[0329] Figure 114 is a cross-sectional view showing the process of attaching the semiconductor thin film 1510 to the first transfer substrate 1512. As shown in Figure 114, the upper surface of the semiconductor thin film 1510 is attached to the adhesive layer 1513 provided on the first transfer substrate 1512. The first transfer substrate 1512 and the adhesive layer 1513 are formed in the same manner as the first transfer substrate 112 and adhesive layer 113 of Embodiment 1, respectively.

[0330] Figure 115 is a cross-sectional view showing the process of separating the semiconductor thin film 1510 by removing the growth substrate 1501. As shown in Figure 115, the semiconductor thin film 1510 is separated from the growth substrate 1501 (InP substrate) by wet etching. As the etchant, an etchant is used in which the etching rate of InP is greater than the etching rate of InGaAs and which does not erode the first transfer substrate 1512 and the adhesive layer 1513 (for example, hydrochloric acid, a mixture of hydrochloric acid and phosphoric acid, or a mixture of hydrochloric acid and nitric acid). The thickness of the first stop layer 1502 is set to a thickness that allows the etching to be stopped at this time.

[0331] Figures 116(A) and (B) are cross-sectional and plan views showing the process of patterning the semiconductor thin film 1510. As shown in Figures 116(A) and (B), the semiconductor thin film 1510 is etched along pre-set separation regions to form a grid-like groove G1. Figures 116(A) and (B) show portions of the semiconductor thin film 1510 separated into 4 rows and 4 columns (16 regions).

[0332] The semiconductor thin film 1510 is patterned by etching that reaches from the first stop layer 1502 to the adhesive layer 1513. The etching method is the same as the patterning process for the semiconductor thin film 1210 in Embodiment 12.

[0333] Figure 117 is a cross-sectional view showing the process of forming a protective film 1515 that covers the semiconductor thin film 1510. As shown in Figure 117, a protective film 1515 is formed that covers the side and bottom surfaces of the semiconductor thin film 1510. The material and method of forming the protective film 1515 are the same as those for the protective film 111 in Embodiment 1.

[0334] Figure 118 is a cross-sectional view showing the process of removing a portion (bottom) of the protective film 1515. As shown in Figure 118, the bottom of the protective film 1515 is removed to expose the lower surface of the first stop layer 1502. The removal of the bottom of the protective film 1515 can be carried out in the same manner as the removal of the bottom of the protective film 1215 in Embodiment 12.

[0335] Figure 119 is a cross-sectional view showing the process of removing the first stop layer 1502 of the semiconductor thin film 1510. The first stop layer 1502 (InGaAs) of the semiconductor thin film 1510 is removed by wet etching. As the etchant, an etchant is used in which the etching rate of InGaAs is greater than that of InP and which does not erode the protective film 1515, the first transfer substrate 1512, and the adhesive layer 1513 (for example, phosphoric acid, or a mixture of phosphoric acid and hydrogen peroxide).

[0336] Figure 120 is a cross-sectional view showing the process of removing the second stop layer 1503 of the semiconductor thin film 1510. The second stop layer 1503 (InP) of the semiconductor thin film 1510 is removed by wet etching. As the etchant, an etchant is used in which the etching rate of InP is greater than that of InGaAs and which does not erode the protective film 1515, the first transfer substrate 1512, and the adhesive layer 1513 (for example, hydrochloric acid, a mixture of hydrochloric acid and phosphoric acid, or a mixture of hydrochloric acid and nitric acid).

[0337] Figure 121 is a cross-sectional view showing the process of removing the protective film 1515 covering the semiconductor thin film 1510. The protective film 1515 covering the semiconductor thin film 1510 is removed by etching. The removal of the protective film 1515 is performed by wet etching or dry etching using the same etchant as in the process of removing the bottom of the protective film 1515.

[0338] Subsequently, the semiconductor thin film 1510 is bonded to the intermediate substrate, the first transfer substrate is removed, the intermediate sacrificial layer of the intermediate substrate is partially removed by etching, and then the semiconductor thin film 1510 is selectively separated from the intermediate substrate and bonded to the device substrate to form electrodes, etc. These steps are the same as steps S107 to S112 of Embodiment 1.

[0339] As described above, in Embodiment 15, the first stop layer 1502 and the second stop layer 1503 are sequentially removed by etching, so less residue remains on the underside of the semiconductor thin film 1510. Therefore, in addition to the effects described in Embodiment 12, the yield in the bonding process to the device substrate is improved.

[0340] Embodiments 12 to 15 described the case in which the semiconductor layer is divided into multiple semiconductor thin films after the growth substrate is removed (i.e., patterned as shown in Figures 94(A) and (B)). However, for example, the semiconductor layer may be separated from the growth substrate by removing the sacrificial layer, and then the semiconductor layer may be divided into multiple semiconductor thin films.

[0341] The embodiments 1 to 15 and their variations described above can be combined as appropriate.

[0342] For example, in Embodiment 3, an example was described in which a metal film 315 is bonded to a semiconductor thin film 310. However, in other embodiments, a metal film may be provided on a semiconductor thin film 110, and this metal film may be bonded to a metal film provided on a device substrate.

[0343] In the embodiments 1 to 15 and their modifications described above, predetermined processing (removal of stop layer, formation of metal layer) is performed after separating the semiconductor thin film from the growth substrate. However, the semiconductor thin film may be bonded to an intermediate substrate and a support layer may be formed without performing the predetermined processing. In other words, even if the semiconductor thin film is not subjected to the predetermined processing, it is possible to efficiently and selectively transfer the semiconductor thin film to the device substrate.

[0344] Furthermore, in embodiments 1 to 9, 11 to 13, and 15 described above, a stop layer (i.e., an etching stop layer) for controlling the etching of the growth substrate is provided as a predetermined layer, but it does not necessarily have to be a stop layer. The predetermined layer may also be a buffer layer for matching the lattice constants of the growth substrate and the semiconductor thin film crystallized on it. If a predetermined layer is formed on the lower surface of the semiconductor thin film (the surface separated from the growth substrate or the surface from which the growth substrate has been removed), such a layer degrades the characteristics of the device (for example, a layer with high electrical resistivity or a layer with many crystal defects), or a layer that hinders the bonding of the semiconductor thin film to the device substrate (for example, a layer with low surface smoothness), a step of removing the predetermined layer may be performed.

[0345] In the embodiments 1 to 15 and their modifications described above, examples using an InP substrate as the growth substrate were explained, but the substrate is not limited to InP; for example, a GaAs substrate may also be used. In this case, a GaAs layer, an AlGaAs layer, an AlInGaP layer, and an InP layer can be epitaxially grown on the GaAs substrate, and wet etching can be performed using an etchant with a selectivity ratio between each material. For example, hydrochloric acid, a mixture of hydrochloric acid and phosphoric acid, a mixture of phosphoric acid and hydrogen peroxide, or a mixture of ammonia and hydrogen peroxide can be used as the etchant.

[0346] Alternatively, a Si substrate or a sapphire substrate may be used as the growth substrate to grow a GaN-based semiconductor thin film (functional layer). When a GaN-based semiconductor thin film is grown on a Si substrate, the semiconductor thin film can be separated by wet etching using an alkaline solution such as potassium hydroxide, or a mixture of nitric acid and hydrofluoric acid. When a GaN-based semiconductor thin film is grown on a sapphire substrate, the semiconductor thin film can be separated by dry etching or laser lift-off because the sapphire substrate is chemically stable.

[0347] In the embodiments 1 to 15 and their modifications described above, photoelectric conversion devices such as photodiodes and LEDs were described as examples of semiconductor devices. However, embodiments 1 to 15 and their modifications are not limited to methods for manufacturing photoelectric conversion devices, but can be applied to methods for manufacturing various semiconductor devices, including, for example, switch elements and power devices.

[0348] Although desirable embodiments have been described in detail above, this disclosure is not limited to the embodiments described above, and various improvements or modifications can be made.

[0349] 1,3 Semiconductor devices, 10,30 Semiconductor support structures, 101,201,301,401,501,601,701,801,901,1001,1101,1201,1301,1401,1501 Growth substrates, 102,202,302,402,1002,1202,1302,1402, Buffer layers, 103,203-205,303,404,502,602,702,1102,1502-1503 Stop layers (etching stop layers, predetermined layers), 104, 206, 304, 405, 505, 604, 707, 805, 904, 1004, 1105, 1204, 1306, 1404, 1505 Lower cladding layer, 105, 207, 305, 406, 506, 605, 708, 806, 905, 1005, 1106, 1205, 1307, 1405, 1506 Active layer, 106, 208, 306, 407, 507, 606, 709, 807, 906, 1006, 1107, 1206, 1308, 1406, 1507 Upper cladding layer, 107, 209, 307, 408, 508, 607, 706, 808, 907, 1003, 1104, 1207, 1309, 1403, 1504 Contact layer, 110, 210, 310, 410, 510, 610, 710, 810, 910, 1010, 1110, 1210, 1310, 1410, 1510 Semiconductor thin film (semiconductor crystal layer, functional layer), 111, 211, 311, 411, 511, 611, 711, 811, 911, 1011, 1111, 1215, 1315, 1515 Protective film (coating film), 112, 212, 312, 412, 512, 612, 712, 812, 912, 1012, 1112, 1212, 1312, 1412, 1512 First transfer substrate, 113, 213, 313, 413, 513, 613, 713, 813, 913, 1013, 1113, 1213, 1313, 1413, 1513 Adhesive layer, 120, 320, 520 Intermediate substrate, 121, 321, 521 Intermediate sacrificial layer (sacrificial layer), 122, 322, 522 Support layer, 123, 323, 523 Void, 130, 330 Second transfer substrate, 131, 331 Stamp, 140, 340 Device substrate, 141,341 First electrode, 142,342 Second electrode, 403,503,603,703,802,902 Sacrificial layer.

Claims

1. A method for manufacturing a semiconductor support structure, comprising the steps of: obtaining a plurality of semiconductor thin films formed from a semiconductor layer grown on a growth substrate and not bonded to the growth substrate; bonding the plurality of semiconductor thin films to a sacrificial layer formed on an intermediate substrate different from the growth substrate; and forming a plurality of support layers that support the plurality of semiconductor thin films by partially removing the sacrificial layer, thereby forming a gap between the first surface of each semiconductor thin film facing the intermediate substrate and the intermediate substrate.

2. The method for manufacturing a semiconductor support structure according to claim 1, wherein the plurality of semiconductor thin films are formed by dividing the semiconductor layer that has been crystallized on the growth substrate, and after dividing the semiconductor layer into the plurality of semiconductor thin films, the plurality of semiconductor thin films are separated from the growth substrate, or the growth substrate is removed leaving the plurality of semiconductor thin films.

3. The method for manufacturing a semiconductor support structure according to claim 1, characterized in that the plurality of semiconductor thin films are formed by separating the semiconductor layer crystallized on the growth substrate from the growth substrate, or by removing the growth substrate while leaving the semiconductor layer and then dividing the semiconductor layer.

4. A method for manufacturing a semiconductor support structure according to any one of claims 1 to 3, characterized in that, after the step of obtaining the plurality of semiconductor thin films, the method further comprises the step of performing a predetermined treatment on the first surface of each semiconductor thin film.

5. The method for manufacturing a semiconductor support structure according to claim 4, characterized in that the predetermined process is the formation of a metal film.

6. A method for manufacturing a semiconductor support structure according to any one of claims 1 to 5, characterized in that, after the step of obtaining the plurality of semiconductor thin films, the method further comprises the step of removing a predetermined layer formed on the side of the semiconductor thin film that is separated from the growth substrate or on the side from which the growth substrate has been removed.

7. The method for manufacturing a semiconductor support structure according to claim 6, characterized in that the predetermined layer includes two or more etching stop layers, and the step of removing the predetermined layer includes two or more etching steps of removing the two or more etching stop layers with different etchants.

8. A method for manufacturing a semiconductor support structure according to any one of claims 1 to 7, characterized in that, after the step of obtaining the plurality of semiconductor thin films, the method further comprises the step of removing an etching stop layer formed on the surface of the growth substrate.

9. A method for manufacturing a semiconductor support structure according to any one of claims 1 to 8, comprising the step of forming a protective film to cover each semiconductor thin film, and after the step of bonding the plurality of semiconductor thin films to the sacrificial layer, the step of removing the protective film.

10. A method for manufacturing a semiconductor support structure according to any one of claims 1 to 9, further comprising the step of forming grooves on the side of the sacrificial layer opposite to the intermediate substrate before the step of bonding the plurality of semiconductor thin films to the sacrificial layer, in which the plurality of semiconductor thin films are bonded so as to overlap the grooves of the sacrificial layer, and in the step of partially removing the sacrificial layer, the plurality of support layers are formed on the side to which the plurality of semiconductor thin films are bonded.

11. The method for manufacturing a semiconductor support structure according to any one of claims 1 to 10, characterized in that the plurality of support layers are composed of organic materials.

12. A method for manufacturing a semiconductor device, comprising the steps of: selectively separating at least one semiconductor thin film from the support layer among the plurality of semiconductor thin films of the semiconductor support structure manufactured by the method for manufacturing a semiconductor support structure according to any one of claims 1 to 10; and bonding the at least one semiconductor thin film to a device substrate different from the growth substrate and the intermediate substrate.

13. A semiconductor support structure comprising a substrate, a plurality of support layers formed on the substrate, and a plurality of semiconductor thin films formed by crystal growth on a growth substrate different from the substrate and supported by the plurality of support layers, wherein a gap is formed between the first surface of each semiconductor thin film facing the substrate and the substrate.

14. The semiconductor support structure according to claim 13, characterized in that the support layer is formed inward from the outer circumference of the first surface.

15. The semiconductor support structure according to claim 13 or 14, characterized in that the plurality of support layers are composed of organic materials.

16. The semiconductor support structure according to any one of claims 13 to 15, characterized in that the plurality of semiconductor thin films have a metal film on the side that is bonded to the plurality of support layers.

17. The semiconductor support structure according to any one of claims 13 to 16, characterized in that the plurality of support layers have grooves on the surfaces that are joined to the plurality of semiconductor thin films.

18. The semiconductor support structure according to claim 17, characterized in that the plurality of support layers have a first groove extending in a first direction on a plane parallel to the plane on which they are joined to the plurality of semiconductor thin films, and a second groove extending in a second direction perpendicular to the first direction.

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