Cathode component, cathode, high-speed atomic beam source, and method for manufacturing a bonded substrate

Abstract

To provide a cathode member, a cathode, a high-speed atom beam source, and a manufacturing method of a bonded substrate, each enabling suppression of emission of a large-sized foreign matter from the high-speed atom beam source.SOLUTION: A tabular cathode member constituting a cathode of a high-speed atom beam source is provided, comprising a plane which constitutes a cathode-inner surface having contour constituted of four corners and four sides connecting the corners. The tabular cathode member comprises in the plane: a first region which includes the corners and the sides and in which a re-deposition amount of sputter dust generated by spluttering is more than a removal amount of the cathode member by the sputtering generated by using the high-speed atom beam source; and a second region excluding the first region from the plane. The first region has an average value of surface roughness Ra larger than that in the second region.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a cathode member, a cathode, a high-speed atomic beam source, and a bonding substrate.

Background Art

[0002] One of the techniques for bonding semiconductor substrates is a substrate bonding technique using high-speed atomic beam irradiation. This technique irradiates an atomic beam onto the bonding target surface of a semiconductor substrate to remove surface contamination and oxide films, and exposes dangling bonds, which are unbonded hands, to activate the surface. Then, the bonding target surfaces of the semiconductor substrates are overlapped and pressed together to bond the semiconductor substrates (see, for example, Patent Document 1). Patent Document 1 discloses a method for manufacturing a bonding substrate having a structure in which a single-crystalline substrate formed in a thin layer is provided on a support substrate. In this manufacturing method, two different materials are integrated by applying the substrate bonding technique.

[0003] As an atomic beam source (FAB gun, (Fast Atom Beam)) used for bonding semiconductor substrates, a saddle-field type high-speed atomic beam source is used. The saddle-field type high-speed atomic beam source supplies an inert gas such as argon, neon, or xenon into a cathode housing having an anode inside, ionizes the inert gas atoms by applying a voltage between the anode and the cathode, and extracts a beam of inert gas atoms from an opening provided in a part of the cathode to irradiate the bonding target surface of the semiconductor substrate. Since most of the ionized inert gas atoms capture electrons on the way to the cathode and are irradiated as neutral atomic beams, there is little electrostatic repulsion between atoms, and the beam has high directivity and is irradiated onto the substrate.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

[0005] In the manufacturing of bonded substrates (Figure 1) using substrate bonding technology, bonding defects may occur during the bonding process. Figure 1 is a schematic perspective view showing a bonded substrate 750 manufactured by bonding a first semiconductor substrate 710 and a second semiconductor substrate 720. Here, Figure 3 is a cross-sectional view showing an example of a bonding defect. The bonding defect shown in Figure 3 is caused by the inclusion of foreign matter m at the bonding interface 730, which is the contact area between the first semiconductor substrate 710 and the second semiconductor substrate 720, resulting in a localized void V where the substrates are not in contact. The presence of a void V at the bonding interface 730 can affect various properties of the final product, the bonded substrate 750.

[0006] Possible routes for contamination by foreign matter m include, for example, insufficient cleaning of the first semiconductor substrate 710 and the second semiconductor substrate 720, the cleanliness of the equipment used in the bonding process, or the emission of foreign matter from particle sources of various particle beams used in the irradiation process of the bonding process. Figure 2 is a schematic diagram showing the irradiation of the bonding target surface 711 of the first semiconductor substrate 710 with a high-speed atomic beam source 800. In Figure 2, foreign matter m is emitted from the high-speed atomic beam source 800 and adheres to the bonding target surface 711 of the first semiconductor substrate 710. When the second semiconductor substrate 720 is bonded to the bonding target surface 711 to which such foreign matter m is attached, a void V may be generated, as shown in Figure 3.

[0007] Focusing on the emission of foreign matter from particle sources of various particle beams as one of the pathways for the introduction of foreign matter m, a high-speed atomic beam source and a bonding apparatus equipped therewith have been proposed that can suppress the emission of foreign matter from a high-speed atomic beam source (see, for example, Patent Document 2). In the invention disclosed in Patent Document 2, in a high-speed atomic beam source used for irradiating the bonding surface of a substrate with an atomic beam, the material of the cathode member used inside the high-speed atomic beam source is selected for the purpose of suppressing the emission of foreign matter generated when irradiating with an atomic beam.

[0008] In experiments conducted by the inventors of this invention, it was revealed that foreign matter emitted from a high-speed atomic beam source can be divided into two types: one that is generated at a constant rate and another whose number increases over time. Furthermore, it was found that the foreign matter that increases over time not only increases in number but also tends to increase in size.

[0009] Figure 4 shows an example of a bonding defect that occurs when a large foreign object (M in Figure 4) is mixed into the bonding interface 730 of a bonded substrate 750 formed by joining a first semiconductor substrate 710 and a second semiconductor substrate 720. When the size of the foreign object mixed into the bonding interface 730 increases, in addition to increasing the size of the resulting bonding defect (F in Figure 4), it can lead to a bonding defect accompanied by damage C to the first semiconductor substrate 710 being bonded. Bonding defects accompanied by damage C are more likely to occur when the first semiconductor substrate 710 being bonded is a thin layer. Bonding defects accompanied by damage C to the first semiconductor substrate 710 shown in Figure 4 have a greater impact on the characteristics of the bonded substrate 750 in terms of both size and structure compared to undamaged defects, and therefore it is particularly important to suppress their occurrence. For this reason, regarding the emission of foreign objects from a high-speed atomic beam source, it is necessary to suppress not only the number of foreign objects but also the generation of particularly large foreign objects.

[0010] Therefore, the present invention aims to provide a cathode member, a cathode, a high-speed atomic beam source, and a method for manufacturing a bonded substrate that can suppress the emission of large foreign matter from a high-speed atomic beam source. [Means for solving the problem]

[0011] The cathode member of the present invention is a flat cathode member that constitutes the cathode of a high-speed atomic beam source, and comprises a plane that constitutes the inner surface of the cathode, the plane having a contour formed by four corners and four sides connecting the corners, the plane having a first region that includes the corners and sides and is a region in which the amount of sputter dust reattached by sputtering is greater than the amount of the cathode member removed by sputtering caused by the use of the high-speed atomic beam source, and a second region which is the region obtained by removing the first region from the plane, the first region having a larger average surface roughness Ra than the second region.

[0012] The cathode component of the present invention may be made of graphite, glassy carbon, or silicon carbide.

[0013] The cathode of the present invention is a cathode for a high-speed atomic beam source and comprises the cathode member of the present invention, having a hollow box shape with six inner surfaces, the six inner surfaces comprising a bottom surface, an upper surface opposite to the bottom surface, and four side surfaces connecting the bottom surface and the upper surface, the four side surfaces being parallel to each other when facing each other, and in one pair of two pairs of facing side surfaces, one side is provided with an inert gas inlet for introducing an inert gas into the cathode, and the other side is provided with a high-speed atomic beam emission port for emitting a high-speed atomic beam to the outside of the cathode.

[0014] The high-speed atomic beam source of the present invention comprises a cathode of the present invention and a first anode and a second anode, which are cylindrical and have the same cylindrical cross-sectional shape, wherein the first anode and the second anode are spaced apart from each other inside the cathode, the central axes of the first anode and the second anode are parallel to each other and are also parallel to any of the four sides, and the shortest distance between the central axis of the first anode and the side having the high-speed atomic beam emission port is the same as the shortest distance between the central axis of the second anode and the side having the high-speed atomic beam emission port.

[0015] In the high-speed atomic beam source of the present invention, if the distance between the central axes of the first anode and the second anode is P, and the radius of the cylindrical cross-section of the first anode and the second anode is r, then in a cross-section perpendicular to the central axes of the first anode and the second anode, the width W of the second region in the cross-section of the cathode member having the high-speed atomic beam emission port may be W ≥ P - 2r.

[0016] In the high-speed atomic beam source of the present invention, if the distance between the central axes of the first anode and the second anode is P, and the radius of the cylindrical cross-section of the first anode and the second anode is r, then the width W of the second region in the cross-section of the cathode member having the high-speed atomic beam emission port, in a cross-section perpendicular to the central axes of the first anode and the second anode, may be W ≤ P + 2r.

[0017] The present invention relates to a method for manufacturing a bonded substrate, comprising: an irradiation step of irradiating a bonding target surface of the first semiconductor substrate and a bonding target surface of the second semiconductor substrate with a high-speed atomic beam in a vacuum using a high-speed atomic beam source described in any one of claims 4 to 6; a contact step of bringing the bonding target surface of the first semiconductor substrate and the bonding target surface of the second semiconductor substrate, which have been irradiated with the high-speed atomic beam, into contact to obtain a laminate having a bonding interface; and a heat treatment step of heat treating the laminate obtained in the bonding step to obtain a bonded substrate.

[0018] In the method for manufacturing a bonded substrate of the present invention, the first semiconductor substrate and the second semiconductor substrate may each be any of the following: a 3C-SiC single crystal substrate, a 4H-SiC single crystal substrate, a 6H-SiC single crystal substrate, or a SiC polycrystalline substrate.

[0019] In the method for manufacturing a bonded substrate of the present invention, the high-speed atomic beam may include argon, neon, or xenon. [Effects of the Invention]

[0020] In the case of the cathode member of the present invention, by using a cathode provided with the cathode member of the present invention as a high-speed atomic beam source, it is possible to suppress the ejection of large-sized foreign matter from the high-speed atomic beam source. As a result, the adhesion of large-sized foreign matter to the bonding target surface of the semiconductor substrate is suppressed, and the occurrence of bonding defects accompanied by breakage when bonding the semiconductor substrates is suppressed, thereby enhancing the manufacturing efficiency of the bonded substrate.

[0021] In the case of the cathode of the present invention, by using the cathode of the present invention as a high-speed atomic beam source, it is possible to suppress the ejection of large-sized foreign matter from the high-speed atomic beam source. As a result, the adhesion of large-sized foreign matter to the bonding target surface of the semiconductor substrate is suppressed, and the occurrence of bonding defects accompanied by breakage when bonding the semiconductor substrates is suppressed, thereby enhancing the manufacturing efficiency of the bonded substrate.

[0022] In the case of the high-speed atomic beam source of the present invention, by providing the cathode of the present invention, it is possible to suppress the ejection of large-sized foreign matter from the high-speed atomic beam source. As a result, the adhesion of large-sized foreign matter to the bonding target surface of the semiconductor substrate is suppressed, and the occurrence of bonding defects accompanied by breakage when bonding the semiconductor substrates is suppressed, thereby enhancing the manufacturing efficiency of the bonded substrate.

[0023] In the case of the manufacturing method of the bonded substrate of the present invention, since the bonding target surface of the substrate is irradiated using a high-speed atomic beam source provided with the cathode of the present invention, it is possible to suppress the ejection of large-sized foreign matter from the high-speed atomic beam source. As a result, the adhesion of large-sized foreign matter to the bonding target surface of the semiconductor substrate is suppressed, and the occurrence of bonding defects accompanied by breakage when bonding the semiconductor substrates is suppressed, thereby enhancing the manufacturing efficiency of the bonded substrate.

Brief Description of the Drawings

[0024] [Figure 1] It is a perspective view showing the bonded substrate manufactured in the manufacturing method of the bonded substrate of the present embodiment. [Figure 2]This diagram schematically illustrates the process of irradiating a semiconductor substrate with a high-speed atomic beam 810 from a conventional high-speed atomic beam source. [Figure 3] This is a schematic cross-sectional view illustrating an example of a bonding defect that occurs during the manufacturing of a bonded substrate. [Figure 4] This is a schematic cross-sectional view illustrating another example of a bonding defect that occurs during the manufacturing of bonded substrates. [Figure 5] This is a schematic perspective view of the high-speed atomic beam source of this embodiment. [Figure 6] This is a plan view showing the side surface 130, which is the cathode member of this embodiment. [Figure 7] This is a cross-sectional view showing a cross-section of the high-speed atomic beam source of this embodiment. [Figure 8] This is a cross-sectional view illustrating the first region R1 and the second region R2 in the cross-section of the high-speed atomic beam source of this embodiment. [Figure 9] This is a cross-sectional view showing the state of a conventional high-speed atomic beam source 800 during irradiation with a high-speed atomic beam. [Figure 10] This diagram illustrates the flow chart of the manufacturing method for the bonded substrate of this embodiment. [Figure 11] This figure illustrates a method for manufacturing a bonded substrate according to one embodiment of the present invention. [Figure 12] This graph illustrates an example of the relationship between the size of foreign matter and the size of bonding defects. [Modes for carrying out the invention]

[0025] [High-speed atomic beam source, cathode, and cathode component] A fast atomic beam source, cathode, and cathode component according to one embodiment of the present invention will be described with reference to the drawings.

[0026] The high-speed atomic beam source of this embodiment is a saddle-field type high-speed atomic beam source that supplies an inert gas internally and emits a high-speed atomic beam of ionized inert gas to the outside from a high-speed atomic beam emission port. Furthermore, the high-speed atomic beam source of this embodiment is used, for example, to perform surface treatment on the bonding surface of the substrate before the bonding process when manufacturing a bonded substrate by bonding two semiconductor substrates together. That is, it is used for the purpose of surface treatment in which the high-speed atomic beam emitted from the high-speed atomic beam source is irradiated onto the bonding surface of the substrate to be bonded, thereby activating the surface of the bonding surface.

[0027] Figure 1 is a perspective view showing an example of a bonded substrate manufactured by joining two semiconductor substrates. The bonded substrate 750 is formed in a substantially disc shape. The bonded substrate 750 shown in Figure 1 comprises, for example, a second semiconductor substrate 720 which is a support substrate positioned on the lower side, and a first semiconductor substrate 710 which is a single crystal layer bonded to the upper surface of the second semiconductor substrate 720. The first semiconductor substrate 710 may be formed from, for example, a single crystal of a compound semiconductor (e.g., 6H-SiC, 4H-SiC, GaN, AlN). Alternatively, it may be formed from, for example, a single crystal of a single-element semiconductor (e.g., Si, C).

[0028] Furthermore, various materials can be used for the second semiconductor substrate 720, which serves as the support substrate. Preferably, the second semiconductor substrate 720 has resistance to various thermal processes applied to the first semiconductor substrate 710. Also, preferably, the second semiconductor substrate 720 is made of a material with a small difference in thermal expansion coefficient from the first semiconductor substrate 710. For example, when SiC is used for the first semiconductor substrate 710, the second semiconductor substrate 720 can be made of single-crystal SiC, polycrystalline SiC, single-crystal Si, polycrystalline Si, sapphire, GaN, carbon, etc. Polycrystalline SiC may contain a mixture of various polytypes of SiC crystals. Since polycrystalline SiC containing a mixture of various polytypes can be manufactured without strict temperature control, it is possible to reduce the cost of manufacturing the second semiconductor substrate 720.

[0029] Figure 5 shows a high-speed atomic beam source 500 according to one embodiment of the present invention. The high-speed atomic beam source 500 comprises a cathode 100 and a first anode 210 and a second anode 220 provided inside the cathode 100, which are cylindrical in shape and have the same cylindrical cross-sectional shape. In the high-speed atomic beam source 500, cathode 100, first anode 210 and second anode 220 of this embodiment, the directions of arrows X, Y and Z in Figure 5 are the width direction, depth direction and height direction, respectively.

[0030] The cathode 100 of this embodiment is a hollow box-shaped structure with six inner surfaces and includes a cathode member 103, which will be described later. The cathode 100 also has six inner surfaces: a bottom surface 110, an upper surface 120 opposite the bottom surface 110, and four side surfaces 130, 140, 150, and 160 connecting the bottom surface 110 and the upper surface 120. The bottom surface 110 and the upper surface 120, the side surfaces 130 and 140, and the side surfaces 150 and 160 are parallel to each other. For example, the cathode 100 is a rectangular parallelepiped with inner dimensions of 56 mm in width, 64 mm in depth, and 102 mm in height.

[0031] Furthermore, the bottom surface 110 and the top surface 120 are parallel to the XY plane, the sides 130 and 140 are opposite each other and parallel to the XZ plane, and the sides 150 and 160 are opposite each other and parallel to the YZ plane. In addition, these six inner surfaces are composed of six flat cathode members. In this embodiment, the cathode 100 is formed by assembling the six cathode members into a box shape.

[0032] Of the two opposing sets of sides (sides 130, 140 and sides 150, 160), sides 130 and 140 are provided with a high-speed atomic beam emission port 101 and an inert gas inlet 102. Specifically, side 130 is provided with a high-speed atomic beam emission port 101 from which a high-speed atomic beam of ionized inert gas inside the cathode 100 is emitted. On side 140, which is opposite side 130 in the direction of arrow Y, is provided with an inert gas inlet 102 for introducing inert gas into the cathode 100. In this embodiment, the high-speed atomic beam emission port 101 consists of 25 circular through-holes with a diameter of 2 mm arranged at equal intervals in 5 rows in the height direction and 5 rows in the width direction, near the center of side 130. The inert gas inlet 102 consists of circular through-holes with a diameter of 3 mm, provided on side 140. The shape, number, and location of the high-speed atomic beam emission port and inert gas inlet are not limited to this embodiment and may be in other forms.

[0033] Figure 7 is a cross-sectional view of the fast atomic beam source 500 parallel to the XY plane. In this embodiment, the first anode 210 and the second anode 220 are spaced apart from each other inside the cathode 100, and the central axes of the first anode 210 and the second anode 220 are parallel to each other and also parallel to any of the four sides 130, 140, 150, and 160, and the shortest distance (L1 in Figure 7) between the central axis 210a of the first anode 210 and the side 130 having the fast atomic beam outlet 101 is the same, and the shortest distance (L2 in Figure 7) between the central axis 220a of the second anode 220 and the side 130 having the fast atomic beam outlet 101 is the same. In other words, the first anode 210 and the second anode 220 are positioned such that the central axis 210a of the first anode 210 and the central axis 220a of the second anode 220 are parallel to the Z direction on a cross-section parallel to the XZ plane of the high-speed atomic beam source 500.

[0034] Furthermore, the first anode 210 and the second anode 220 are provided inside the cathode 100 and are fixed inside the cathode 100 via an insulating member (not shown). The first anode 210 and the second anode 220 are cylindrical in shape, with a cross-sectional diameter of 10 mm and a height dimension approximately the same as the height of the cathode 100. The first anode 210 and the second anode 220 have a circular cross-section parallel to the XY plane, and the central axis of the cylinder is parallel to the Z direction. As shown in Figure 7, the two first anodes 210 and the second anodes 220 are provided spaced apart from each other at the middle position in the depth direction of the cathode 100 (32 mm from the sides 130 and 140, respectively), such that the distance between the central axes of the two first anodes 210 and the second anodes 220 is 25 mm.

[0035] Furthermore, the anode material can be graphite, glassy carbon, silicon, silicon carbide, or other materials.

[0036] Furthermore, the negative electrode of the DC power supply is connected to the cathode 100, and the positive electrode of the DC power supply is connected to the first anode 210 and the second anode 220, and a high voltage of, for example, 0.8kV to 2kV is applied. This generates an electric field, causing the inert gas introduced into the cathode 100 from the inert gas inlet 102 to ionize, and plasma is generated between the two first anodes 210 and the second anode 220. In addition, the positive ions of the inert gas capture and neutralize electrons that are accumulating near the side surface 130 having the fast atomic beam emission port 101 and the opposite side surface 140, and are emitted from the fast atomic beam emission port 101 to the outside of the fast atomic beam source 500 as a fast atomic beam 510 (Figure 11). At this time, the flow rate of the inert gas is adjusted so that the irradiation current is, for example, about 10mA to 100mA.

[0037] The cathode member 103 is flat and has a plane that constitutes the inner surface of the cathode 100, with a contour formed by four corner portions 103a and four sides 103b connecting the corner portions 103a. This plane includes a first region R1 (Figures 6 and 8) which includes the corner portions 103a and sides 103b, and where the amount of sputter dust reattached by sputtering is greater than the amount of cathode member 103 removed by sputtering caused by the use of the high-speed atomic beam source 500, and a second region R2 (Figures 6 and 8) which is the region obtained by removing the first region R1 from the plane.

[0038] Here, Figure 6 is a plan view of the side surface 130 of the cathode member 103, and the area where sputter dust tends to accumulate after using the high-speed atomic beam source for a certain period of time is indicated by a diagonal line. Thus, the area where sputter dust tends to accumulate, including the corners 103a and edges 103b of the cathode member, is the first region R1, and the area inside the first region R1 excluding the first region R1 is the second region R2. In the cathode member of this embodiment, the average surface roughness Ra of the first region R1 is greater than that of the second region R2. In the following description, when surface roughness Ra is mentioned, it refers to the average surface roughness Ra in that region. The thickness of the cathode member 103 can be, for example, about 1 mm to 5 mm.

[0039] Furthermore, the first region R1 only needs to have a larger average surface roughness Ra than the second region R2. For example, a buffer region with a surface roughness Ra intermediate between the first and second regions R2 may be provided at the boundary between the first and second regions R1. Alternatively, the surface roughness Ra near the boundary between the first and second regions R2 may be continuously varied. By setting the surface roughness Ra in stages in this way, more precise design becomes possible to reduce bonding defects that result in breakage.

[0040] Furthermore, the surface shape of the cathode member for setting the predetermined surface roughness Ra is not limited. In particular, in the first region R1, increasing the surface area is effective in suppressing the peeling of sputter dust deposits, but various shapes can be applied, not just isotropic shapes, but also uneven or wavy shapes to distribute internal stresses in order to avoid the deposited sputter dust becoming planar.

[0041] Here, as shown in Figure 8, if P is the distance between the central axes of the first anode 210 and the second anode 220, and r is the radius of the cylindrical cross-section of the first anode 210 and the second anode 220, then in a cross-section perpendicular to the central axes 210a and 220a of the first anode 210 and the second anode 220 (a cross-section S parallel to the XY plane shown in Figure 11), the width W of the second region R2 in cross-section S of the cathode member (side surface 130) equipped with the high-speed atomic beam emission port 101 can be set to W ≥ P - 2r. Furthermore, if P is the distance between the central axes of the first anode 210 and the second anode 220, and r is the radius of the cylindrical cross-section of the first anode 210 and the second anode 220, then in a cross-section S perpendicular to the central axes 210a and 220a of the first anode 210 and the second anode 220, the width W of the second region R2 in cross-section S of the cathode member (side surface 130) equipped with the high-speed atomic beam emission port 101 can be set to W ≤ P + 2r. Through our investigations, we have found that in the cathode member after irradiation with a high-speed atomic beam for a predetermined time, the surface shape is relatively smooth up to a width of P-2r relative to the center of the cathode member, and the smoothness is gradually lost from P-2r to P+2r, but no deposits were found. In addition, in the region outside P+2r, a film-like deposit exists, and furthermore, it was confirmed that some of it had peeled off. By defining the second region R2 as described above, the surface roughness Ra of the cathode component in the first region R1 and the second region R2 can be appropriately set according to the mechanism of foreign matter generation, thereby effectively suppressing the emission of foreign matter from the high-speed atomic beam source.

[0042] Furthermore, the cathode member of this embodiment is suitable to be formed from a material that is conductive and highly resistant to sputtering that occurs inside the high-speed atomic beam source during particle beam irradiation, for example, graphite, glassy carbon, or silicon carbide.

[0043] (Bonding defects in the manufacturing process of bonded substrates) Here, we will explain the bonding defects that may occur during the manufacturing process of bonded substrates. <Size of foreign matter in joint defects> This section describes a type of bonding defect in the manufacturing process of bonded substrates that is caused by the emission of foreign matter from a high-speed atomic beam source. Figure 2 schematically shows how the high-speed atomic beam 810 is irradiated from the high-speed atomic beam source 800 onto the bonding target surface 711 of the first semiconductor substrate 710 during the irradiation process. Here, irradiation of the first semiconductor substrate 710 is given as an example, but a similar phenomenon can occur when irradiating the second semiconductor substrate 720, which is located opposite. Foreign matter m is emitted from inside the high-speed atomic beam source, and as shown in Figure 2, this foreign matter m may fly and adhere to the bonding target surface 711 of the first semiconductor substrate 710. In this state, when the first semiconductor substrate 710 and the second semiconductor substrate 720 are joined, at the bonding interface 730 formed by the contact of the bonding target surfaces 711 and 712 of the first semiconductor substrate 710 and the second semiconductor substrate 720, contact between the bonding target surfaces 711 and 721 is inhibited in the areas where foreign matter m is present. As a result, as shown in Figure 3, a localized gap V where there is no contact may occur. This gap V results in a bonding defect.

[0044] The size of the bonding defect depends on the size of the foreign matter m, the bonding strength of the bonding surfaces 711 and 721, and the mechanical strength of the first semiconductor substrate 710 and the second semiconductor substrate 720. Of these, the bonding strength of the bonding surfaces 711 and 721 depends on the irradiation conditions during irradiation with a high-speed atomic beam and the heat treatment conditions after bonding. Furthermore, the mechanical strength of the first semiconductor substrate 710 and the second semiconductor substrate 720 depends on the physical properties and thickness of these substrates, and the size of the bonding defect strongly depends on the size of the foreign matter m adhering to the bonding surfaces 711 and 721.

[0045] Figure 12 shows an example of the relationship between the size of foreign matter m and the size of the bonding defect. The thickness of the first semiconductor substrate 710 here is approximately 1 μm. Figure 12 shows that there is a positive correlation between the size (diameter) of foreign matter m and the size (diameter) of the bonding defect. Furthermore, as the size of foreign matter m increases, not only does the size of the bonding defect increase, but differences in its morphology also appear. In bonding defects, foreign matter m acts like a wedge on the first semiconductor substrate 710 and the second semiconductor substrate 720 that are being bonded, applying pressure to each surface. Therefore, as the size of foreign matter m increases, the pressure applied to the bonded objects increases, and when it exceeds the mechanical strength of the semiconductor substrate itself, it results in a bonding defect accompanied by damage to the semiconductor substrate itself, as shown in Figure 4. This tendency is particularly pronounced when the semiconductor substrate being bonded is thin. Bonding defects accompanied by damage to the bonded objects have a greater impact on the characteristics of the substrate compared to bonding defects without damage shown in Figure 3, so it is especially important to suppress their occurrence. In the example shown in Figure 12, the size of the defective joint expands as the size (diameter) of the foreign object increases, and when it exceeds approximately 5 μm, the size of the defective joint becomes 40 μm or larger, and it is accompanied by damage to the object being joined. This highlights the need to suppress the generation of foreign objects larger than 5 μm.

[0046] <Classification of foreign matter size and bonding failure mechanism> The mechanism by which foreign matter m is generated from inside the high-speed atomic beam source will be explained with reference to Figure 9.

[0047] Figure 9 shows the cross-section of a conventional high-speed atomic beam source 800 in a cross-section parallel to the XY plane, during irradiation with a high-speed atomic beam. The high-speed atomic beam source 800 has the same configuration as the high-speed atomic beam source 500, except that the surface roughness Ra of the cathode member 903 is uniform.

[0048] First, the inert gas G introduced from the inert gas inlet 902 is ionized between the first anode 210 and the second anode 220, to which a DC voltage (for example, approximately 0.8kV to 2kV) is applied, becoming a positive ion e. This positive ion e accelerates towards the cathode 900, is neutralized by electrons lingering near the high-speed atomic beam emission port 901, and is emitted outside the high-speed atomic beam source 800 as a high-speed atomic beam 810.

[0049] On the other hand, positive ions e that are not emitted outside the high-speed atomic beam source 800 collide with the inner surface of the cathode 900 that constitutes the high-speed atomic beam source 800, sputtering the cathode member 903. The cathode dust generated by this sputtering (hereinafter referred to as sputtered dust 905) becomes the source of foreign matter m. Experiments conducted by the inventors of this application revealed that there are two types of mechanisms for the generation of foreign matter originating from sputtered dust 905 generated inside the high-speed atomic beam source 800.

[0050] One type of foreign matter is sputtering dust originating from the cathode, which is ejected directly to the outside and acts as relatively small foreign matter. On the other hand, sputtering dust that remains inside the high-speed atomic beam source without being ejected to the outside reattaches to the inner surface of the cathode, forming aggregates that accumulate in a film-like manner at the corners of the cathode, thus forming deposits. As the thickness of these deposits increases, they peel off from the inner surface of the cathode, and some of them may be ejected to the outside. These ejected deposit fragments are the other type of foreign matter, and because these foreign matter are aggregates of sputtering dust, they are characterized by their large size. Such large foreign matter acts as a cause of bonding failures, including the damage shown in Figure 4 (C).

[0051] Thus, there is a strong correlation between the generation mechanism and the surface shape of the cathode material from which foreign matter originates from sputtered dust on the cathode of a high-speed atomic beam source. First, regarding the sputtered dust that is the source of the foreign matter, it is generated in the area where the amount of sputtering removed is greater (second region R2) of the cathode material, by comparing the amount of sputtering removed with the amount of re-adhesion of the generated sputtered dust. The number of generated sputtered dusts depends on the amount of sputtering removed from the cathode material, and the amount of sputtering removed depends on the energy of the charged particles and the surface area of ​​the object being sputtered.

[0052] Therefore, in order to suppress the generation of sputter dust in the high-speed atomic beam source 500 of this embodiment, it is considered effective to reduce the surface area of ​​the object to which charged particles collide, and it is effective to reduce the surface roughness of the cathode member that is the target of sputtering. The optimal surface roughness of the second region R2 depends on the specifications for bonding defects required in the final product, but for example, the surface roughness Ra can be 0.3 μm or less, and even 0.1 μm or less.

[0053] Larger foreign objects are generated in the cathode component in areas where sputtering removes sputtering dust and the amount of sputtering dust reattached is greater (first region R1). The number of such objects depends not only on the amount of sputtering dust generated as the source of the foreign objects, but also on the ease with which the deposits formed by the reattachment of sputtering dust can be removed. The ease with which the deposits can be removed depends on the adhesive strength between the deposits and the cathode component, and on the deposition pattern of the deposits. Generally, it is known that the adhesive strength between two bodies tends to increase with increasing contact area.

[0054] Therefore, in order to suppress the generation of large foreign matter in the high-speed atomic beam source 500 of this embodiment, it is considered effective to increase the surface area of ​​the cathode member that comes into contact with the deposits, and it is considered effective to increase the surface roughness of the cathode member that is the target of sputtering by the high-speed atomic beam. The optimal surface roughness of the first region R1 depends on the specifications for bonding defects required for the final product, but for example, the surface roughness Ra can be greater than 0.3 μm, and even greater than 1.0 μm.

[0055] In this invention, regarding foreign matter emitted from a high-speed atomic beam source, which is a cause of bonding defects in the manufacturing of bonded substrates, the relationship between the type of bonding defect caused by foreign matter, the type of foreign matter generated from the high-speed atomic beam source, and the location of its generation has been clarified. Based on this knowledge, by making the average value of the surface roughness Ra of the first region R1 greater than the average value of the surface roughness Ra of the second region R2, it is possible to suppress the generation of large foreign matter that can become a source of bonding defects accompanied by damage to the bonded object, which have a particularly significant impact on the substrate characteristics.

[0056] In the cathode member of this embodiment, the first region R1 has a higher average surface roughness Ra than the second region R2, thereby suppressing the generation of sputter dust, which is the source of large foreign matter in the second region R2, and suppressing the peeling of deposits formed by the re-adhesion of sputter dust in the first region R1. As a result, the emission of large foreign matter from the high-speed atomic beam source, which is generated by the peeling and falling of deposits, can be suppressed. In other words, when a cathode equipped with the cathode member of this embodiment is used in a high-speed atomic beam source, the adhesion of large foreign matter M to the bonding surface of the semiconductor substrate is reduced, thereby suppressing the occurrence of bonding defects accompanied by damage, and improving the manufacturing efficiency of the bonded substrate.

[0057] [Method for manufacturing bonded substrates] Next, a method for manufacturing a bonded substrate according to one embodiment of the present invention will be described with reference to Figures 10 and 11. Figure 10 is a diagram illustrating the flow of the method for manufacturing a bonded substrate according to this embodiment. Figure 11(A) is a schematic diagram showing a bonding apparatus 600 irradiating the bonding target surfaces 711 and 721 of the first semiconductor substrate 710 and the second semiconductor substrate 720 with a high-speed atomic beam 510. Figure 11(B) is a schematic cross-sectional view showing the first semiconductor substrate 710' and the second semiconductor substrate 720' after the irradiation process. Figure 11(C) is a schematic cross-sectional view showing the laminate 700 obtained after the contact process. In this embodiment, as an example, the case in which the first semiconductor substrate 710 is a single-crystal 4H-SiC substrate which is a single-crystal layer, and the second semiconductor substrate 720 is a polycrystalline SiC substrate which is a support substrate is illustrated.

[0058] The method for manufacturing a bonded substrate according to this embodiment is a method for manufacturing a bonded substrate in which a first semiconductor substrate and a second semiconductor substrate are laminated. The method comprises an irradiation step (S1 in Figure 10) in which a high-speed atomic beam 510 is irradiated in a vacuum onto the bonding target surface 711 of the first semiconductor substrate 710 and the bonding target surface 721 of the second semiconductor substrate 720 using the high-speed atomic beam source 500 of the embodiment described above, and a contact step (S2 in Figure 10) in which the bonding target surface 711 of the first semiconductor substrate 710' and the bonding target surface 721 of the second semiconductor substrate 720', which have been irradiated with the high-speed atomic beam 510, are brought into contact to obtain a laminate having a bonding interface 730. Furthermore, the method for manufacturing a bonded substrate according to this embodiment may further include a heat treatment step (S3 in Figure 10) in which the laminate 700 obtained in the bonding step is heat-treated to obtain a bonded substrate.

[0059] In the manufacturing method of the bonded substrate of this embodiment, the first semiconductor substrate 710 and the second semiconductor substrate 720 can be any of the following: a 3C-SiC single crystal substrate, a 4H-SiC single crystal substrate, a 6H-SiC single crystal substrate, or a SiC polycrystalline substrate. Furthermore, when the first semiconductor substrate 710 is a single crystal layer, it is not limited to a 4H-SiC single crystal. Various polytypes of single crystal SiC, such as 3C-SiC and 6H-SiC, can be used, and a delamination technique by hydrogen atom ablation (also known as SmartCut®) may be used to form the single crystal layer. Also, when the first semiconductor substrate 710 is a single crystal layer, the second semiconductor substrate 720 may be any material that has resistance to the various thermal processes applied to the single crystal layer.

[0060] Furthermore, the high-speed atomic beam 510 may contain argon, neon, or xenon.

[0061] The bonding apparatus 600 comprises a housing, two high-speed atomic beam sources 500, a vacuum pump (not shown) for creating a vacuum inside the housing, and holding means (not shown) for holding the first semiconductor substrate 710 and the second semiconductor substrate 720, and for moving the first semiconductor substrate 710 and the second semiconductor substrate 720 to predetermined positions in each manufacturing process. As shown in Figure 11, the two high-speed atomic beam sources 500 are positioned to irradiate the bonding target surface 711 of the first semiconductor substrate 710 and the bonding target surface 721 of the second semiconductor substrate 720 with the high-speed atomic beams 510.

[0062] The specific procedure will be explained with reference to Figures 10 and 11. First, a first semiconductor substrate 710 and a second semiconductor substrate 720 are prepared. Preferably, the surfaces of the first semiconductor substrate 710 and the second semiconductor substrate 720 are planarized. Planarization may be performed by grinding or cutting, or by the CMP method.

[0063] First, as step S1, an irradiation process is performed. As shown in Figure 11(A), the irradiation process involves irradiating the bonding target surface 711 of the first semiconductor substrate 710 and the bonding target surface 721 of the second semiconductor substrate 720 with a high-speed atomic beam 510 from a high-speed atomic beam source 500. As a result, the bonding target surfaces 711 and 721 are activated, and the first semiconductor substrate 710' and the second semiconductor substrate 720' are obtained.

[0064] Activation of the bonding surfaces 711 and 721 refers to the removal of interface termination components such as oxygen, hydrogen, and hydroxyl groups (OH groups), as well as oxide films, from the bonding surfaces 711 and 721 of the first semiconductor substrate 710 and the second semiconductor substrate 720, thereby exposing dangling bonds that are not yet bonded. Furthermore, when irradiated with a high-speed atomic beam, the crystal structure of the bonding surfaces 711 and 721 can be destroyed at a certain depth from the surface. As a result, amorphous layers containing Si and C are formed on the surfaces of the first semiconductor substrate 710 and the second semiconductor substrate 720. An amorphous layer is a layer in which atoms do not have the same regularity as a crystal structure.

[0065] The procedure involves placing the first semiconductor substrate 710 and the second semiconductor substrate 720 in the chamber of the bonding apparatus 600 so that the bonding target surface 711 of the first semiconductor substrate 710 and the bonding target surface 721 of the second semiconductor substrate 720 face each other, as shown in Figure 11(A), and then aligning their relative positions. This alignment is performed so that the two substrates can contact each other in the correct positional relationship during the bonding process described later. Next, the inside of the housing is evacuated, for example, 1 × 10⁻¹⁰ -4 ~1 × 10 -7 Maintain a vacuum of approximately (Pa).

[0066] Next, the bonding surface 711 of the first semiconductor substrate 710 and the bonding surface 721 of the second semiconductor substrate 720 are irradiated with a high-speed atomic beam 510 using a high-speed atomic beam source 500.

[0067] The high-speed atomic beam 510 is irradiated onto the entire surface of the bonding target surface 711 of the first semiconductor substrate 710 and the bonding target surface 721 of the second semiconductor substrate 720.

[0068] Next, a contact process is performed as step S2. As shown in Figure 11(B), the first semiconductor substrate 710' and the second semiconductor substrate 720' are moved in the direction that brings the bonding surfaces 711 and 721 closer together (in the direction of the arrows in Figure 11(B)) until the bonding surfaces 711 and 721 come into contact. After the bonding surfaces 711 and 721 come into contact, a predetermined load (for example, 100 kgf (0.98 kN)) is applied and held for a predetermined time (for example, 3 minutes). This causes the dangling bonds present on the activated bonding surfaces 711 and 721 to bond together, thereby bonding the first semiconductor substrate 710' and the second semiconductor substrate 720'. With this, the contact process is completed, and a laminate 700 (Figure 11(C)) having a bonding interface 730 is obtained.

[0069] Next, as step 3, a heat treatment process is performed. In the heat treatment process, the laminate 700 is heat-treated while the amorphous layers of the first semiconductor substrate 710' and the second semiconductor substrate 720' are in contact with each other. The heat treatment process is carried out using a furnace. The heat treatment process may be carried out under reduced pressure in the chamber of the bonding apparatus 600, or it may be carried out in a furnace other than the chamber.

[0070] In the heat treatment step, the laminate 700 of the first semiconductor substrate 710' and the second semiconductor substrate 720' is heated to a predetermined temperature. The predetermined temperature may be determined according to the material of the bonding substrate. For example, when using SiC, it may be heated to 1000°C or higher (preferably around 1500°C). This allows the amorphous layers of the first semiconductor substrate 710' and the second semiconductor substrate 720' to be recrystallized from a state where the atomic arrangement is irregular to a state where the atomic arrangement is regular. Once the recrystallization is complete, the amorphous layer disappears, and a bonding substrate is formed in which the first semiconductor substrate 710 and the second semiconductor substrate 720 are directly bonded.

[0071] According to the manufacturing method of the bonded substrate of this embodiment, the bonding target surfaces 711 and 721 of the first semiconductor substrate 710 and the second semiconductor substrate 720 are irradiated using a high-speed atomic beam source 500 equipped with a cathode 100. This suppresses the emission of deposits from the high-speed atomic beam source 500, i.e., the ejection of large foreign matter, and thus suppresses the adhesion of large foreign matter onto the bonding target surfaces 711 and 721. As a result, when bonding the first semiconductor substrate 710 and the second semiconductor substrate 720 together, the occurrence of bonding defects, particularly those involving damage to the first semiconductor substrate 710 and the second semiconductor substrate 720, is suppressed, thereby improving the yield and increasing the manufacturing efficiency of the bonded substrate.

[0072] Furthermore, the present invention is not limited to the embodiments described above, and includes other processes and the like that can achieve the objectives of the present invention, as well as variations of the embodiments described above.

[0073] The technical elements described herein or in the drawings demonstrate technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies illustrated herein or in the drawings can achieve multiple objectives simultaneously, and achieving even one of these objectives constitutes technical usefulness in itself.

[0074] Furthermore, while the best configurations, methods, etc., for carrying out the present invention are disclosed in the above description, the present invention is not limited thereto. That is, although the present invention is described in particular with respect to specific embodiments, those skilled in the art can make various modifications to the embodiments described above in terms of shape, material, quantity, and other detailed configurations without departing from the scope of the technical idea and objectives of the present invention. Therefore, the descriptions of shapes, materials, etc. disclosed above are illustrative to facilitate understanding of the present invention and do not limit the present invention. Accordingly, descriptions of components with some or all of the limitations on shape, material, etc. removed are included in the present invention. [Examples]

[0075] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited in any way by these examples.

[0076] [Example 1] As the cathode, the cathode 100 of the embodiment described above was used. Specifically, the cathode was made of glassy carbon, with a width of 56 mm, a height of 102 mm, and a depth of 64 mm, and the thickness of the cathode material was 3 mm.

[0077] Furthermore, two cylindrical graphite anodes, each 10 mm in diameter and 100 mm in length, were used as the first anode 210 and the second anode 220. The two anodes were fixed to the bottom surface 110 and the top surface 120 of the cathode 100 via an insulating material, spaced apart from each other, at the center of the depth direction of the cathode 100 (32 mm from the sides 130 and 140, respectively), with a central axis distance of 25 mm between the two anodes.

[0078] An inert gas, argon (Ar) gas, was introduced into the cathode 100 through the inert gas inlet. The acceleration voltage for irradiation with a fast atomic beam from the fast atomic beam source 500 was set to 1 kV, and the Ar gas flow rate was adjusted so that the irradiation current was 30 mA, and irradiation was performed. The first and second semiconductor substrates used were silicon substrates with a diameter of 150 mm (6 inches) and a thickness of 625 μm. In Example 1, the surface roughness Ra of the first region and the surface roughness Ra of the second region were set to 1.0 μm and 0.1 μm respectively on the plane of the cathode material constituting the inner surface of the cathode 100, respectively, by blast processing. The surface roughness was measured at three locations in each region, and the average value was used.

[0079] First, using cathode 100 with an accumulated irradiation time of 3 hours from an unused state, the number of foreign particles adhering to the surface of the silicon substrate was measured after 300 seconds of beam irradiation under the above irradiation conditions. Next, using cathode 100 with an accumulated usage time of 15 hours, the number of foreign particles adhering to the surface of the silicon substrate was measured after 300 seconds of beam irradiation. The number of foreign particles was measured using a particle counter (model WM-7S, manufactured by TOPCON) to determine the total number of foreign particles, the number of foreign particles with a diameter of 5 μm or less, and the number of foreign particles with a diameter greater than 5 μm. After 15 hours of accumulated usage time, if the number of foreign particles with a diameter of 5 μm or less was 400 or less, and the number of foreign particles with a diameter greater than 5 μm was 5 or less, it was determined that the ejection of foreign particles was sufficiently suppressed, and the occurrence of bonding defects accompanied by damage was extremely low. The results are shown in Table 1. The results are shown in Table 1.

[0080] Furthermore, a first semiconductor substrate (a 350 μm thick single-crystal SiC substrate) and a second semiconductor substrate (a 350 μm thick polycrystalline SiC substrate) were irradiated using a high-speed atomic beam source after 15 hours of cumulative irradiation. These substrates were then subjected to contact and heat treatment processes to fabricate bonded substrates. After delamination by hydrogen atom ablation to thin the single-crystal SiC substrate into a 1 μm thick single-crystal SiC layer, the presence or absence of bonding defects (size 40 μm or larger and accompanied by damage) was evaluated. As a result, no such bonding defects were observed.

[0081] [Example 2] Foreign matter adhering to the surface of the silicon substrate was measured in the same manner as in Example 1, except that the surface roughness Ra of the first region was set to 0.5 μm and the surface roughness Ra of the second region was set to 0.1 μm on the plane of the cathode member constituting the inner surface of cathode 100. The results are shown in Table 1.

[0082] Furthermore, a bonded substrate was fabricated using a high-speed atomic beam source after 15 hours of cumulative irradiation, in the same manner as described in Example 1, and the presence or absence of bonding defects (size of 40 μm or larger and accompanied by damage) was evaluated. As a result, no such bonding defects were observed.

[0083] [Example 3] Foreign matter adhering to the surface of the silicon substrate was measured in the same manner as in Example 1, except that the surface roughness Ra of the first region was set to 1.0 μm and the surface roughness Ra of the second region was set to 0.3 μm on the plane of the cathode member constituting the inner surface of cathode 100. The results are shown in Table 1.

[0084] Furthermore, a bonded substrate was fabricated using a high-speed atomic beam source after 15 hours of cumulative irradiation, in the same manner as described in Example 1, and the presence or absence of bonding defects (size of 40 μm or larger and accompanied by damage) was evaluated. As a result, no such bonding defects were observed.

[0085] [Comparative Example 1] Foreign matter adhering to the surface of the silicon substrate was measured in the same manner as in Example 1, except that the surface roughness Ra of the first region and the surface roughness Ra of the second region were set to 0.1 μm on the plane of the cathode member constituting the inner surface of cathode 100. The results are shown in Table 1.

[0086] Furthermore, a bonded substrate was fabricated using a high-speed atomic beam source after 15 hours of cumulative irradiation, in the same manner as described in Example 1, and the presence or absence of bonding defects (size of 40 μm or larger and accompanied by damage) was evaluated. As a result, eight bonding defects with sizes ranging from 60 μm to 200 μm and accompanied by damage were found.

[0087] [Table 1]

[0088] As shown in the results in Table 1, in Examples 1 to 3, increasing the surface roughness Ra of the second region compared to the first region suppressed the injection of foreign matter, particularly those larger than 5 μm. Furthermore, it was suggested that the greater the surface roughness Ra, the greater the effect of suppressing the injection of foreign matter larger than 5 μm.

[0089] In Examples 1 to 3, which are exemplary embodiments of the present invention, it has been shown that by making the surface roughness Ra of the region (first region) in the cathode member where sputtering dust generated by the sputtering phenomenon tends to accumulate greater than that of the second region, the emission of deposits can be suppressed, and the adhesion of particularly large foreign matter to the bonding target surface of the semiconductor substrate irradiated with a high-speed atomic beam can be suppressed. As a result, bonding defects can be suppressed when bonding semiconductor substrates together, and the manufacturing efficiency of the bonded substrate can be improved. [Explanation of symbols]

[0090] 100 cathode 101 High-speed atomic beam outlet 102 Inert gas inlet 103 Cathode component 103a Corner 103b side 110 Base 120 Top 130 Side view 140 Side view 150 Side view 160 Side view 210 1st anode 220 2nd anode 500 Fast atomic beam sources 750 bonded substrate 710 First semiconductor substrate 720 Second semiconductor substrate 711,721 Surfaces to be joined R1 First area R2 second area

Claims

1. A flat plate-shaped cathode member that constitutes the cathode of a high-speed atomic beam source, The cathode has a plane that forms the inner surface, whose outline is formed by four corners and four sides connecting the corners, In the plane, there is a first region which includes the corner and the edge, and in which the amount of sputter dust reattached by sputtering is greater than the amount of the cathode member removed by sputtering caused by the use of the high-speed atomic beam source, It has a second region which is the region obtained by removing the first region from the plane, The first region is a cathode member in which the average value of the surface roughness Ra is greater than that of the second region.

2. The cathode member according to claim 1, which is made of graphite, glassy carbon, or silicon carbide.

3. The cathode of a high-speed atomic beam source, The cathode member described in claim 1 is a hollow box-shaped structure having six inner surfaces, The six inner surfaces include a bottom surface, an upper surface facing the bottom surface, and four side surfaces connecting the bottom surface and the upper surface. The four aforementioned sides are such that opposing sides are parallel to each other. A cathode in which, of the four sides, one of two opposing sets of sides is provided with an inert gas inlet for introducing an inert gas into the cathode, and the other is provided with a high-speed atomic beam outlet for emitting a high-speed atomic beam to the outside of the cathode.

4. The cathode according to claim 3, It comprises a first anode and a second anode, which are cylindrical in shape and have the same cylindrical cross-sectional shape, The first anode and the second anode are separated from each other within the cathode. The central axes of the first anode and the second anode are parallel to each other and also parallel to any of the four sides. A high-speed atomic beam source in which the shortest distance between the central axis of the first anode and the side surface having the high-speed atomic beam emission port is the same as the shortest distance between the central axis of the second anode and the side surface having the high-speed atomic beam emission port.

5. If P is the distance between the central axes of the first anode and the second anode, and r is the radius of the cylindrical cross-section of the first anode and the second anode, The high-speed atomic beam source according to claim 4, wherein in a cross-section perpendicular to the central axes of the first anode and the second anode, the width W of the second region in the cross-section of the cathode member having the high-speed atomic beam emission port is W ≥ P - 2r.

6. If P is the distance between the central axes of the first anode and the second anode, and r is the radius of the cylindrical cross-section of the first anode and the second anode, The high-speed atomic beam source according to claim 4, wherein in a cross-section perpendicular to the central axes of the first anode and the second anode, the width W of the second region in the cross-section of the cathode member having the high-speed atomic beam emission port is W ≤ P + 2r.

7. A method for manufacturing a bonded substrate in which a first semiconductor substrate and a second semiconductor substrate are stacked, An irradiation step of irradiating the bonding surface of the first semiconductor substrate and the bonding surface of the second semiconductor substrate with a high-speed atomic beam in a vacuum using the high-speed atomic beam source described in claim 4, A contact step to obtain a laminate having a bonding interface by bringing into contact the bonding target surface of the first semiconductor substrate and the bonding target surface of the second semiconductor substrate, which have been irradiated with the high-speed atomic beam, A method for manufacturing a bonded substrate, comprising:

8. The method for manufacturing a bonded substrate according to claim 7, further comprising a heat treatment step of heat-treating the laminate obtained in the contact step to obtain a bonded substrate.

9. The method for manufacturing a bonded substrate according to claim 7, wherein the first semiconductor substrate and the second semiconductor substrate are each one of a 3C-SiC single crystal substrate, a 4H-SiC single crystal substrate, a 6H-SiC single crystal substrate, and a SiC polycrystalline substrate.

10. The method for manufacturing a bonded substrate according to claim 7, wherein the high-speed atomic beam includes argon, neon, or xenon.

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