JP2023178891A - Cathode, high speed atomic beam source, method of manufacturing bonded substrate, and method of regenerating cathode - Google Patents

Abstract

To provide a cathode, a high speed atomic beam source, and the like, which are capable of suppressing the release of particle deposits from the high speed atomic beam source and also suppressing the reduction of the degree of vacuum in the high speed atomic beam source.SOLUTION: A cathode 100 of a high speed atomic beam source has six inner surfaces 110-160. The inner surfaces comprise six flat cathode members 103, and are provided with an inert gas introduction port 102 to introduce inert gas into the cathode and a particle beam emission port 101 to emit high speed atomic beams to the outside of the cathode, and have an adhesive covered area on planes of the cathode members. The adhesive covered area is an area where a re-attachment amount of sputter dust caused by a sputtering phenomenon is larger than a removal amount of the cathode members by the sputtering phenomenon caused by the use of the high speed atomic beam source. A volume ratio of a volume of an adhesive is 1-15% relative to an internal volume of the cathode, and a paste area of an adhesive material 104 is 25% or more on an adhesive surface of the inside of the cathode in the adhesive covered area.SELECTED DRAWING: Figure 3

Description

The present invention relates to a cathode, a fast atomic beam source, a method for manufacturing a bonded substrate, and a method for regenerating a cathode.

One of the techniques for bonding substrates together is room-temperature bonding technology using high-speed atomic beam irradiation. This process involves irradiating the surfaces of the substrates to be bonded with an atomic beam to remove surface contamination and oxide films, as well as exposing the dangling bonds and activating the surfaces. This is a technology that joins substrates by overlapping them and pressing them together at room temperature.

As an atomic beam source used for room temperature bonding, a saddle field type fast atomic beam source is used (for example, see Patent Document 1).The saddle field type fast atomic beam source has an anode inside. An inert gas such as argon (Ar) gas (hereinafter, argon gas will be explained as an example) is supplied into the cathode housing, and the inert gas atoms are ionized by applying a voltage between the anode and the cathode. An Ar atomic beam is taken out from an opening provided in a part and irradiated onto the substrate. In addition, most of the Ar ions recombine with electrons on the way to the cathode and become a neutral Ar atomic beam. Therefore, there is little electrostatic repulsion between Ar atoms, resulting in a highly directional atomic beam. It has the characteristic of irradiating the substrate.

International Publication No. 2017/038476

In the substrate bonding technology using the above-mentioned fast atomic beam source (FAB gun, (Fast Atom Beam)), along with the Ar atomic beam, some of the particles generated in the fast atomic beam source fly out of the gun and adhere to the substrate. However, it may become a factor that inhibits bonding. That is, in the high-speed atomic beam source, a part of the Ar beam is irradiated onto the cathode housing to cause a sputtering phenomenon, and as a result, particles due to fragments of the cathode housing are generated and become particles. As described above, if these particles fly out from the opening of the cathode on the Ar gas flow and adhere to the substrate, they can become a factor that inhibits bonding.

Furthermore, on the inner surface of the cathode of the fast atom beam source, the above-described sputtering phenomenon and the re-deposition of particles generated by the sputtering (hereinafter sometimes referred to as "re-deposition") occur simultaneously. As the thickness of the deposited layer of sputtered particles increases, it becomes easier to peel off and fall from the inner surface of the cathode, and as larger particles fly out of the high-speed atomic beam source, they are used to bond substrates together. This is a major factor in the occurrence of inhibition. Furthermore, when treating the surface of a substrate to be bonded using a high-speed atomic beam source, the degree of vacuum inside the high-speed atomic beam source affects the efficiency of surface treatment. Therefore, it is required to suppress the emission of particles and to suppress the degree of vacuum inside the fast atomic beam source from decreasing.

Therefore, the present invention provides a cathode, a fast atomic beam source, and a junction that can suppress particle emission from a fast atomic beam source and suppress a decrease in the degree of vacuum within the fast atomic beam source. The present invention aims to provide a method for manufacturing a substrate and a method for regenerating a cathode.

The cathode of the present invention is a cathode for a high-speed atomic beam source, and the cathode has a hollow box shape with six inner surfaces, and the six inner surfaces include a bottom surface and a bottom surface facing the bottom surface. and four side surfaces connecting the bottom surface and the top surface, the six inner surfaces are composed of six flat cathode members, and the four side surfaces are arranged so that the opposing side surfaces are connected to each other. are parallel to each other, and among the four side surfaces, one set of the two opposing side surfaces is provided with an inert gas inlet for introducing an inert gas into the cathode, and the other side is provided with an inert gas inlet for introducing an inert gas into the cathode. A particle beam emitting port for emitting a high-speed atomic beam is provided on the outside of the cathode, and the cathode member has an outline composed of four corners and four sides connecting the corners. The cathode member has an adhesive material-covered region coated with an adhesive material on a plane of the cathode member constituting the inner surface of the cathode, and the adhesive material-covered region is generated by use of the high-speed atomic beam source. The area is a region where the amount of re-deposition of sputter dust generated by the sputtering is larger than the amount of the cathode member removed by the sputtering, and the area covered with the adhesive material has an area ratio of 5 to the area of the entire inner surface. % to 80%, the thickness of the adhesive material is 500 μm or less, and the adhesive force of the surface of the adhesive material exposed to the inner surface of the cathode is 5 N/25 mm to 15 N/25 mm.

In the cathode of the present invention, the adhesive coated region may include the corner portion.

In the cathode of the present invention, the cathode member may be made of graphite, glassy carbon, silicon, or silicon carbide.

The fast atomic beam source of the present invention includes the cathode of the present invention and an anode provided inside the cathode.

A method for manufacturing a bonded substrate according to the present invention is a method for manufacturing a bonded substrate in which a first semiconductor substrate and a second semiconductor substrate are stacked, the method comprising: using a fast atomic beam source according to the present invention; an irradiation step of irradiating a surface to be bonded of the first semiconductor substrate and a surface to be bonded of the second semiconductor substrate with a high-speed atomic beam in a vacuum; and the first semiconductor substrate irradiated with the high-speed atomic beam. and a contact step of bringing the surface to be bonded of the second semiconductor substrate into contact with the surface to be bonded of the second semiconductor substrate to obtain a laminate having a bonding interface.

The method for manufacturing a bonded substrate of the present invention may further include a heat treatment step of heat-treating the laminate obtained in the bonding step to obtain a bonded substrate.

In the method for manufacturing a bonded substrate of the present invention, the first semiconductor substrate and the second semiconductor substrate may be a 3C-SiC single crystal substrate, a 4H-SiC single crystal substrate, a 6H-SiC single crystal substrate, or a SiC polycrystalline substrate, respectively. It may be any crystal substrate.

In the method for manufacturing a bonded substrate of the present invention, the high-speed atomic beam may contain any one of argon, neon, and xenon.

The cathode recycling method of the present invention includes an adhesive removal step of removing an adhesive from the adhesive coated area of the cathode member constituting the cathode after being used in a fast atomic beam source; The method includes a coating step of coating the adhesive-coated area of the cathode member with a new adhesive.

With the cathode of the present invention, by using the cathode of the present invention in a high-speed atomic beam source, it is possible to suppress the emission of particles from the high-speed atomic beam source. Thereby, it is possible to suppress particles from adhering to the surface to be bonded of the semiconductor substrate. Further, it is possible to suppress a decrease in the degree of vacuum inside the fast atomic beam source. As a result, it is possible to suppress the occurrence of bonding inhibition when bonding semiconductor substrates together, and also to suppress the decrease in the efficiency of surface treatment due to a decrease in the degree of vacuum inside the fast atomic beam source. , the manufacturing efficiency of the bonded substrate can be increased.

Since the fast atomic beam source of the present invention includes the cathode of the present invention, particle emission from the fast atomic beam source can be suppressed. Further, it is possible to suppress a decrease in the degree of vacuum inside the fast atomic beam source. As a result, it is possible to suppress particles from adhering to the surfaces of semiconductor substrates to be bonded, suppress the occurrence of bonding inhibition when bonding semiconductor substrates, and reduce the degree of vacuum inside the fast atomic beam source. Since it is possible to suppress a decrease in the efficiency of surface treatment, the manufacturing efficiency of the bonded substrate can be increased.

In the method for manufacturing a bonded substrate of the present invention, since the surface to be bonded of the substrate is irradiated using a fast atomic beam source equipped with the cathode of the present invention, the emission of particles from the fast atomic beam source is suppressed. , it is possible to suppress particles from adhering to the surface to be welded. Further, it is possible to suppress a decrease in the degree of vacuum inside the fast atomic beam source. This improves yield by suppressing bonding inhibition when bonding substrates together, and increases the manufacturing efficiency of bonded substrates by suppressing a decrease in the efficiency of surface treatment of semiconductor substrates. be able to.

With the cathode regeneration method of the present invention, it is possible to suppress the emission of particles again through a simple process after a cathode has been used for a certain period of time, and to suppress the decrease in the degree of vacuum inside the high-speed atomic beam source. Can be played in any condition. Therefore, it is possible to suppress the emission of particles from the fast atomic beam source and the decrease in the degree of vacuum inside the fast atomic beam source, thereby increasing the manufacturing efficiency of the bonded substrate and extending the life of the cathode.

1 is a perspective view schematically showing a fast atomic beam source according to an embodiment of the present invention. FIG. 2 is a plan view schematically showing the state of the inner surface of a cathode member that constitutes a cathode after using a conventional high-speed atomic beam source. 3 is a plan view schematically showing the inner surfaces of six cathode members constituting the cathode used in Example 1. FIG. FIG. 3 is a plan view schematically showing the inner surfaces of six cathode members constituting the cathode used in Example 2. FIG. FIG. 7 is a plan view schematically showing the inner surfaces of six cathode members constituting the cathode used in Example 3. 3 is a plan view schematically showing the inner surfaces of six cathode members constituting the cathode used in Comparative Example 2. FIG. FIG. 3 is a plan view schematically showing the inner surfaces of six cathode members constituting the cathode used in Comparative Example 3. FIG. 3 is a diagram illustrating a method for manufacturing a bonded substrate according to an embodiment of the present invention. FIG. 3 is a diagram illustrating a method for regenerating a cathode according to an embodiment of the present invention.

[Fast atomic beam source, cathode, and cathode member]
A fast atomic beam source, a cathode, and a cathode member according to an embodiment of the present invention will be described with reference to the drawings.

The fast atomic beam source of this embodiment is a saddle field type fast atomic beam source, which supplies an inert gas inside and emits an ionized inert gas atomic beam to the outside from a particle beam emission port. It is something that is emitted. Furthermore, the fast atomic beam source of this embodiment can be used, for example, to perform surface treatment on the surfaces of the substrates to be bonded before the bonding process when manufacturing a bonded substrate in which two semiconductor substrates are bonded together. It will be done. That is, it is used for the purpose of surface treatment of activating the surface of the surface to be bonded by irradiating the surface of the substrate to be bonded with a high-speed atomic beam emitted from a high-speed atomic beam source.

A fast atomic beam source 500 of this embodiment shown in FIG. 1 includes a cathode 100 and an anode 200 provided inside the cathode 100. Note that in the fast atomic beam source 500, cathode 100, and anode 200 of this embodiment, the arrow X direction, arrow Y direction, and arrow Z direction in FIG. 1 are defined as the width direction, depth direction, and height direction, respectively. Note that in FIG. 1, an adhesive material to be described later is omitted.

The cathode 100 of this embodiment has a hollow box shape with six inner surfaces. For example, the cathode 100 has a rectangular parallelepiped shape with internal dimensions of 56 mm in width (w in FIG. 1), 64 mm in depth (d in FIG. 1), and 102 mm in height (h in FIG. 1). The six inner surfaces include a bottom surface 110, a top surface 120 facing the bottom surface 110, and four side surfaces 130, 140, 150, and 160 that connect the bottom surface 110 and the top surface 120.

Further, the bottom surface 110 and the top surface 120 are parallel to the XY plane, the side surfaces 130 and 140 are opposite to each other and parallel to the XZ plane, and the side surfaces 150 and 160 are opposite to each other and parallel to the YZ plane. Further, these six inner surfaces are composed of six flat cathode members 103. In this embodiment, the cathode 100 is formed by assembling six cathode members 103 into a box shape.

Of the two sets of opposing side surfaces (side surfaces 130, 140 and side surfaces 150, 160), the side surfaces 130, 140 are provided with a particle beam outlet 101 and an inert gas inlet 102. That is, the side surface 130 is provided with a particle beam emitting port 101 through which a high-speed atomic beam of an inert gas ionized inside the cathode 100 is emitted. Furthermore, an inert gas introduction port 102 for introducing an inert gas into the cathode 100 is provided on a side surface 140 that faces the side surface 130 in the direction of arrow Y. In this embodiment, the particle beam emission port 101 has a total of 64 circular through holes each having a diameter of 2 mm arranged at equal intervals in 8 rows in the height direction and 8 rows in the width direction near the center of the side surface 130. It is provided. Further, the inert gas inlet 102 is provided with one circular through hole with a diameter of 3 mm near the center of the side surface 140. The shape, number, and location of the particle beam outlet and the inert gas inlet are not limited to those in this embodiment, and may be in other forms.

In this embodiment, two anodes 200 are provided inside the cathode 100, and are fixed inside the cathode 100 via an insulating member (not shown). Further, the anode 200 has a cylindrical shape with a cross-sectional diameter of 10 mm and a height dimension that is approximately the same as the height of the cathode 100. The anode 200 has a circular cross section parallel to the XY plane, and a cylindrical central axis parallel to the Z direction. Further, as shown in FIG. 3, the distance between the center axes of the two anodes 200 is 36 mm at the middle position in the depth direction of the cathode 100 (positions 32 mm from the side surfaces 130 and 140, respectively). They are spaced apart from each other so that

Further, as the material of the anode, graphite, glassy carbon, silicon, silicon carbide, etc. can be used.

Further, a negative electrode of direct current is connected to the cathode 100, and a positive electrode of direct current is connected to the anode 200, and a high voltage of, for example, about 0.5 kV to 5 kV is applied. This generates an electric field, and the inert gas introduced into the cathode 100 from the inert gas inlet 102 is ionized, generating plasma between the two anodes 200. Furthermore, the positive ions of the inert gas receive electrons from the cathode 100 and are emitted from the particle beam outlet 101 to the outside of the fast atomic beam source 500 as a fast atomic beam 510 (FIG. 8). At this time, the flow of the inert gas is adjusted so that the irradiation current is, for example, about 10 mA to 100 mA.

Next, the cathode member 103 will be explained with reference to the side surface 130 of the cathode 100 shown in FIG. FIG. 3 is a plan view of the six cathode members 103 (bottom surface 110, top surface 120, side surfaces 130, 140, 150, 160) constituting the cathode 100, placed so that the inner plane of the cathode is visible.

The cathode member 103 has a plate shape, and has a shape whose outline is composed of four corner parts 103a and four sides 103b connecting the corner parts 103a. The thickness can be, for example, about 1 mm to 5 mm. Further, the cathode member 103 has an adhesive material-covered region covered with an adhesive material 104 on the plane of the cathode member 103 that constitutes the inner surface of the cathode 100 . Note that the through holes of the particle beam discharge port 101 and the inert gas introduction port 102 provided on the side surfaces 130 and 140 are not blocked by the adhesive material 104.

Generally, when using a high-speed atomic beam source, a sputtering phenomenon occurs when the inner surface of the cathode (the surface of the cathode member 103) is irradiated with the high-speed atomic beam, resulting in particles originating from fragments of the cathode housing. This is generated and becomes particles. Further, the particles may be emitted from the particle beam emission port or may be reattached and deposited on the surface of the cathode member 103. That is, in the cathode member 103 constituting the cathode, the sputtering phenomenon and the reattachment of particles generated by the sputtering phenomenon to the surface of the cathode member 103 occur simultaneously. As the thickness of this deposited layer of particles due to the sputtering phenomenon increases, it becomes easier to peel off and fall from the inner surface of the cathode, and is emitted as larger particles from the high-speed atomic beam source when bonding substrates together. This is a major factor in the occurrence of bonding inhibition.

In the cathode member 103 of the present embodiment, the amount of redeposited sputter dust (particles) generated by sputtering is greater than the amount of cathode member 103 removed by sputtering generated by using the high-speed atomic beam source 500 in the adhesive coated area. is a larger area. Further, the area covered with the adhesive material is an area having an area ratio of 5% to 80% of the area of the entire inner surface on the plane of the cathode member 103 constituting the inner surface of the cathode 100. Further, the area ratio (%) of the area covered with the adhesive material can be calculated using the formula: "Area covered with the adhesive material/Area of the entire inner surface of the cathode member x 100 (%)". Note that in calculating the area ratio of the adhesive coated area, the particle beam discharge port 101 and the inert gas inlet port 102 provided on the side surfaces 130 and 140 are assumed to have no holes and are included in the area of the inner surface of the cathode member 103. shall be taken as a thing. If the area covered with the adhesive material is too small, it will be difficult to sufficiently suppress particle emission from the fast atomic beam source.

Further, the thickness of the adhesive material 104 is 500 μm or less. At this time, the entire thickness of the adhesive material 104 only needs to be 500 μm or less, and one adhesive material with a thickness of 500 μm or less may be attached to the adhesive coated area, or multiple sheets of adhesive material with a thickness of 500 μm or less may be attached. Adhesive materials may be applied in layers. By setting the area ratio to 5% to 80% and the thickness of the adhesive material to 500 μm or less, it is possible to suppress a decrease in the degree of vacuum inside the fast atomic beam source using such a cathode 100, and to prevent the semiconductor substrate from decreasing. It is possible to suppress a decrease in the efficiency of surface treatment.

In addition, the adhesive strength of the surface of the adhesive material 104 exposed on the inner surface of the cathode 100 must be such that it will not peel off or fall if particles due to sputtering phenomenon adhere and accumulate, and must be 5N/25mm to 15N. /25mm.

Further, the thickness of the adhesive material 104 can preferably be 150 μm to 450 μm.

Further, the cathode member 103 of this embodiment may be made of, for example, graphite, glassy carbon, silicon, or silicon carbide. In addition, tungsten, molybdenum, titanium, nickel, and alloys and compounds thereof can be used.

By configuring the cathode 100 using the cathode member 103 as described above, even if particles generated by a sputtering phenomenon re-adhere to the surface of the cathode member 103, if the particles adhere to the adhesive material 104, the particles will peel off.・You can prevent it from falling. As a result, by using the cathode 100 constituted by the cathode member 103 of this embodiment in the fast atomic beam source 500 and activating the surface to be bonded of the semiconductor substrate to be bonded, a large amount of radiation from the fast atomic beam source is activated. Particle emission can be suppressed. Further, it is possible to suppress a decrease in the degree of vacuum inside the fast atomic beam source 500, and it is possible to suppress a decrease in the efficiency of surface treatment of a semiconductor substrate. As described above, it is possible to suppress the occurrence of bonding inhibition when bonding the substrates, and also to suppress a decrease in the efficiency of surface treatment of the semiconductor substrate, and it is possible to increase the manufacturing efficiency of the bonded substrate.

Here, FIG. 2 is a plan view schematically showing the state of a side surface 830, which is an example of a cathode member constituting a cathode after using a conventional high-speed atomic beam source. In FIG. 2, the cathode is placed so that its inner surface is visible. The fast atomic beam source using the cathode member 803 (side surface 830) shown in FIG. 2 has the same configuration as the fast atomic beam source of this embodiment, except that the cathode member does not have an area covered with an adhesive material. When using a conventional fast atomic beam source, the part inside the apex of the cathode is less likely to be irradiated with the fast atomic beam than other parts, so the redeposition rate is higher than the sputtering rate, and a deposited layer due to redeposit is likely to occur. . That is, as shown in FIG. 2, particles generated by the sputtering phenomenon tend to re-adhere and accumulate in a region S close to the contour of the cathode member including the four corner portions 803a of the cathode member.

For this reason, as shown in FIG. 3, it is preferable that the area covered with the adhesive material of the cathode member 103 (the area covered with the adhesive material 104) includes the corner portion 103a of the cathode member. By including the corner portion 103a in the area covered with the adhesive material, it is possible to cover an area where the redeporate is particularly large, and it is possible to more effectively suppress the release of particles.

[Method for manufacturing bonded substrate]
Next, a method for manufacturing a bonded substrate according to an embodiment of the present invention will be described with reference to FIG. 8. FIG. 8A is a schematic diagram showing a bonding apparatus 600 that irradiates surfaces 711 and 721 to be bonded of a first semiconductor substrate 710 and a second semiconductor substrate 720 with a high-speed atomic beam 510. Further, FIG. 8B is a cross-sectional view schematically showing the first semiconductor substrate 710' and the second semiconductor substrate 720' after the irradiation process. Moreover, FIG. 8(C) is a cross-sectional view schematically showing the laminate 700 obtained after the contact process.

The method of manufacturing a bonded substrate of this embodiment is a method of manufacturing a bonded substrate in which a first semiconductor substrate 710 and a second semiconductor substrate 720 are stacked, and includes the method of manufacturing a bonded substrate in which a first semiconductor substrate 710 and a second semiconductor substrate 720 are stacked. An irradiation step of irradiating the surface 711 of the first semiconductor substrate 710 to be bonded and the surface 721 of the second semiconductor substrate 720 to be bonded with a high-speed atomic beam 510 in a vacuum, and irradiation with the high-speed atomic beam 510 using contacting the bonding target surface 711 of the first semiconductor substrate 710' and the bonding target surface 721 of the second semiconductor substrate 720' to obtain a laminate 700 having a bonding interface 730. . Further, the method for manufacturing a bonded substrate according to the present embodiment may further include a heat treatment step of heat-treating the laminate 700 obtained in the bonding step to obtain a bonded substrate.

The bonding apparatus 600 holds a housing, two high-speed atomic beam sources 500, a vacuum pump (not shown) that evacuates the inside of the housing, a first semiconductor substrate 710, and a second semiconductor substrate 720. , a holding means (not shown) for moving the first semiconductor substrate 710 and the second semiconductor substrate 720 to predetermined positions in each manufacturing process. As shown in FIG. 8, the two high-speed atomic beam sources 500 irradiate a high-speed atomic beam 510 onto a surface to be bonded 711 of a first semiconductor substrate 710 and a surface to be bonded 721 of a second semiconductor substrate 720. is set up. In this embodiment, the first semiconductor substrate 710 and the second semiconductor substrate 720 are each irradiated with the fast atomic beam 510. , at least one of the second semiconductor substrates 720 may be irradiated.

The specific procedure will be explained with reference to FIG. The first semiconductor substrate 710 and the second semiconductor substrate 720 are placed in the bonding apparatus 600 so that the surface to be bonded 711 of the first semiconductor substrate 710 and the surface 721 to be bonded of the second semiconductor substrate 720 face each other. The inside of the housing is evacuated to a vacuum state of, for example, 10 ⁻⁴ Pa or less.

First, an irradiation process is performed. In the irradiation step, as shown in FIG. 8A, a fast atomic beam 510 is applied from a fast atomic beam source 500 to a surface 711 of the first semiconductor substrate 710 to be bonded and a surface 721 of the second semiconductor substrate 720 to be bonded. This is the process of irradiating the As a result, a first semiconductor substrate 710' and a second semiconductor substrate 720' with activated surfaces 711 and 721 to be bonded are obtained.

Activation of the surfaces 711 and 721 to be bonded refers to interface termination components such as oxygen, hydrogen, and hydroxyl groups (OH groups) on the surfaces 711 and 721 to be bonded of the first semiconductor substrate 710 and the second semiconductor substrate 720; This refers to removing the oxide film and forming dangling bonds.

Next, a contact step is performed. As shown in FIG. 8(B), the first semiconductor substrate 710', the first semiconductor substrate 710', and the The second semiconductor substrate 720' is moved. The inside of the casing 600 is pressurized to a predetermined pressure (for example, 100 kgf (0.98 kN)). The first semiconductor substrate 710' and the second semiconductor substrate 720' are bonded by holding for a predetermined time (for example, 3 minutes). The contacting step is thus completed, and a laminate 700 (FIG. 8C) having a bonding interface 730 is obtained.

Next, a heat treatment step is performed. A bonded substrate of the first semiconductor substrate 710 and the second semiconductor substrate 720 is obtained by heat-treating the obtained laminate 700 by setting the inside of the casing of the bonding device 600 to about 300° C., for example.

In the method for manufacturing a bonded substrate of this embodiment, the first semiconductor substrate 710 and the second semiconductor substrate 720 are respectively a 3C-SiC single crystal substrate, a 4H-SiC single crystal substrate, a 6H-SiC single crystal substrate, and a SiC It can be any of the polycrystalline substrates.

Furthermore, the high-speed atomic beam 510 can contain any one of argon, neon, and xenon.

According to the method for manufacturing a bonded substrate of the present embodiment, the surfaces 711 and 721 to be bonded of the first semiconductor substrate 710 and the second semiconductor substrate 720 are irradiated using the fast atomic beam source 500 including the cathode 100. Therefore, emission of particles from the high-speed atomic beam source 500 is suppressed, and adhesion of particles to the surfaces 711 and 721 to be welded can be suppressed. Further, it is possible to suppress a decrease in the degree of vacuum inside the fast atomic beam source 500, and it is possible to suppress a decrease in the efficiency of surface treatment of a semiconductor substrate. This improves the yield by suppressing the occurrence of bonding inhibition when bonding the first semiconductor substrate 710 and the second semiconductor substrate 720, and also prevents the efficiency of surface treatment of the semiconductor substrates from decreasing. By suppressing this, the manufacturing efficiency of the bonded substrate can be increased.

[Cathode regeneration method]
Next, a cathode regeneration method according to an embodiment of the present invention will be described with reference to FIG. In FIG. 9, the side surface 130, which is the cathode member 103 constituting the cathode 100, will be illustrated and explained.

The cathode regeneration method of this embodiment is applied to the purpose of regenerating the cathode 100 of the embodiment described above. Adhesive material removal step of removing adhesive material 104 from the adhesive material-coated area of cathode member 103 constituting cathode 100 after use in fast atomic beam source 500, and adhesive coating of cathode member 103 from which adhesive material 104 has been removed. and a covering step of covering the area with new adhesive material 104.

The specific procedure will be explained with reference to FIG. First, the cathode 100 after being used for a certain period of time is disassembled and each cathode member is made into one cathode member. FIG. 9 illustrates a process of regenerating the side surface 130' of the cathode 100 after it has been used for a certain period of time. First, in the adhesive removal step (S1), the adhesive 104' is removed from the cathode member 103 (side surface 130') to obtain the cathode member 103 from which the adhesive has been removed. Next, in a coating step (S2), the adhesive coated area of the cathode member is again coated with a new adhesive 104 having a predetermined shape, thereby obtaining a cathode member (side surface 130). In this way, for other cathode members constituting the cathode 100, buffer members coated with new adhesive material 104 can be obtained through the adhesive material removal process and the coating process.

Furthermore, using the buffer member obtained in the coating process, the cathode 100 is assembled into the shape of the cathode 100 to obtain a recycled cathode 100. In the manner described above, the cathode can be regenerated after being used for a certain period of time. Since the cathode 100 is coated with an adhesive material 104 in areas where particles tend to accumulate, the cathode recycling method of this embodiment removes the adhesive material 104' on which particles have accumulated and replaces the unused adhesive material. The cathode 100 can be regenerated to a state with less particle accumulation by a simple method of replacing the cathode 104 with the cathode 104.

Particles are deposited on the adhesive coated area of the cathode 100 after being used for a certain period of time, and there is a possibility that the deposited particles may fall off and be emitted outside the high-speed atomic beam source 500. Therefore, it is considered better to replace the cathode 100 that has been used for a certain period of time with an unused cathode 100 (or a cathode 100 with less particle accumulation). Therefore, with the cathode regeneration method of the present embodiment, even if particles are deposited on the cathode 100 after being used for a certain period of time, the cathode 100 can be brought into a state with few particles deposited through a simple process. , it can be regenerated to a state where particle emission can be sufficiently suppressed again. Therefore, the emission of particles from the fast atomic beam source 500 and the decrease in the degree of vacuum inside the fast atomic beam source are suppressed to improve the manufacturing efficiency of bonded substrates, and the entire cathode member can be replaced as particles accumulate. This eliminates the need for the cathode, and the life of the cathode can be extended.

Note that the present invention is not limited to the embodiments described above, but includes other steps that can achieve the object of the present invention, and variations of the embodiments described above are also included in the present invention.

In addition, the best configuration, method, etc. for carrying out the present invention have been disclosed in the above description, but the present invention is not limited thereto. That is, although the present invention has been specifically described mainly with respect to specific embodiments, there may be changes in shape, material, quantity, Various modifications can be made by those skilled in the art in other detailed configurations. Therefore, the descriptions in which the shapes, materials, etc. disclosed above are limited are provided as examples to facilitate understanding of the present invention, and are not intended to limit the present invention. Descriptions of names of members that exclude some or all of the limitations such as these are included in the present invention.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples of the present invention, but the present invention is not limited to these Examples in any way.

[Example 1]
As the cathode member, the cathode member of the embodiment described above (FIG. 3, bottom surface 110, top surface 120, side surfaces 130, 140, 150, 160) was used. That is, the cathode had a width of 56 mm, a height of 102 mm, and a depth of 64 mm, and the thickness of the cathode member was 3.2 mm. Further, the cathode member was made of graphite and was covered with an adhesive material 104 having the dimensions shown in FIG. 3 to form an adhesive coated area (the area indicated by diagonal lines in FIG. 3). The adhesive used had an adhesive strength of 10 N/25 mm on both the surface to be attached to the cathode member and the surface exposed inside the cathode, and had a thickness of 150 μm. In the cathode 100 of Example 1, the area ratio of the area covered with the adhesive material (area covered with the adhesive material/area of the entire inner surface of the cathode member x 100 (%)) was 66.2%.

The cathode members as described above were assembled into a rectangular parallelepiped shape as shown in FIG. 1 to form a cathode. Further, as the anodes 200, two cylindrical graphite anodes each having a diameter of 10 mm and a length of 100 mm were used. As shown in FIG. 3, the two anodes 200 are connected to each other through an insulating member at the central position of the cathode 100 in the depth direction (32 mm from the side surfaces 130, 140). They were fixed to the bottom surface 110 and the top surface 120 at a distance of 36 mm from each other.

As the inert gas, argon (Ar) gas was introduced into the cathode 100 from an inert gas inlet. The acceleration voltage for high-speed atomic beam irradiation from the high-speed atomic beam source 500 was 1 kV, and the Ar gas flow was adjusted so that the irradiation current was 30 mA. As the first semiconductor substrate and the second semiconductor substrate, silicon substrates having a diameter of 152 mm (6 inches) and a thickness of 625 μm were used.

Under the above irradiation conditions, the silicon substrate was first irradiated with the beam for 300 seconds in the initial installation state of the fast atomic beam source 500, and then the number of particles on the first semiconductor substrate was counted. This number of particles was defined as the "initial number of particles." The number of particles was measured using a particle counter (model WM-7S, manufactured by TOPCON) under conditions of an edge exclusion of 5 mm and a minimum particle detection size of 0.15 μm.

Next, the irradiation was repeated intermittently for 30 minutes and paused until the cumulative usage time (integrated value of irradiation time only) reached 20 hours, and then the unused first semiconductor substrate and the second A semiconductor substrate was placed and irradiated with a high-speed atomic beam for 300 seconds. The number of particles on the first semiconductor substrate after irradiation for 300 seconds was measured, and this was defined as the "number of particles after 20 hours of use." Then, the increase ratio of the number of particles from the initial state (initial number of particles/number of particles after 20 hours of use) was calculated. It was evaluated that when this increase ratio was 10 times or less, the emission of particles was sufficiently suppressed and the occurrence of major defects in bonding was extremely low. As a result of the irradiation test in Example 1, the rate of increase in the number of particles was doubled.

In addition to measuring the number of particles, we also evaluated the effect on the degree of vacuum inside the fast atomic beam source. The evaluation was performed by comparing the degree of vacuum between a fast atomic beam source to which an adhesive was attached and a fast atomic beam source to which no adhesive was attached (Comparative Example 1). The evaluation criteria for the influence on the degree of vacuum were set as follows, and in the cases of A to C, it was judged that the decrease in the degree of vacuum was suppressed. As a result of the evaluation, in Example 1, the influence on the degree of vacuum was evaluated as C.
A: It is the same as when no adhesive material is attached, and there is no decrease in the degree of vacuum.
B: The degree of vacuum was slightly lower than when no adhesive was attached, but this did not affect production.
C: The degree of vacuum was lower than when no adhesive was attached, but the predetermined degree of vacuum was reached by increasing the evacuation time.
D: The degree of vacuum is lower than when no adhesive is attached, and even if the vacuuming time is extended, it is difficult to reach the desired degree of vacuum, and although the product can be obtained, the efficiency of surface treatment is extremely poor. Productivity was difficult.

Furthermore, a contact process and a heat treatment process were performed using the first semiconductor substrate and the second semiconductor substrate, which had been subjected to an irradiation process using a high-speed atomic beam source after being used for 20 hours, to produce a bonded substrate. As a result, no bonding inhibition occurred, and a bonded substrate was obtained that was normally bonded.

[Example 2]
Next, Example 2 was conducted. The cathode was a cathode 100A shown in FIG. 4, and (bottom surface 110A, top surface 120A, side surfaces 130A, 140A, 150A, 160A) were used as cathode members. The cathode member is coated with adhesive material 104A as shown in the drawing. In addition, the area ratio of the area covered with the adhesive material (area covered with the adhesive material/area of the entire surface of the cathode member) was 31.7%. An irradiation test was conducted in the same manner as in Example 1 except for the cathode member. As a result of calculating the rate of increase in the number of particles from the initial state, the rate of increase was three times. Moreover, the influence on the degree of vacuum was evaluated as B. Furthermore, as a result of manufacturing the bonded substrate, no bonding inhibition occurred and a bonded substrate was obtained that was normally bonded.

[Example 3]
Next, Example 3 was conducted. The cathode was the cathode 100B shown in FIG. 5, and (bottom surface 110B, top surface 120B, side surfaces 130B, 140B, 150B, 160B) were used as the cathode members. The cathode member is coated with an adhesive material 104B as shown in the drawing. In addition, the area ratio of the area coated with the adhesive material (area covered with the adhesive material/area of the entire surface of the cathode member) was 8.7%. An irradiation test was conducted in the same manner as in Example 1 except for the cathode member. As a result of calculating the increase rate of the number of particles from the initial state, the increase rate was 5 times. Moreover, the influence on the degree of vacuum was rated A. Furthermore, as a result of manufacturing the bonded substrate, no bonding inhibition occurred and a bonded substrate was obtained that was normally bonded.

[Example 4]
Next, Example 4 was conducted. In Example 4, tests and evaluations were performed in the same manner as in Example 1, except that the thickness of the adhesive was set to 300 μm by stacking two sheets of adhesive. As a result of calculating the increase rate of the number of particles from the initial state, the increase rate was twice. Further, the influence on the degree of vacuum was rated C. Furthermore, as a result of manufacturing the bonded substrate, no bonding inhibition occurred and a bonded substrate was obtained that was normally bonded.

[Example 5]
Next, Example 5 was conducted. In Example 5, tests and evaluations were performed in the same manner as in Example 2, except that the thickness of the adhesive was set to 300 μm by stacking two sheets of adhesive. As a result of calculating the rate of increase in the number of particles from the initial state, the rate of increase was three times. Moreover, the influence on the degree of vacuum was evaluated as B. Furthermore, as a result of manufacturing the bonded substrate, no bonding inhibition occurred and a bonded substrate was obtained that was normally bonded.

[Example 6]
Next, Example 6 was conducted. In Example 6, tests and evaluations were performed in the same manner as in Example 3, except that the thickness of the adhesive was set to 300 μm by stacking two sheets of adhesive. As a result of calculating the increase rate of the number of particles from the initial state, the increase rate was 5 times. Moreover, the influence on the degree of vacuum was evaluated as B. Furthermore, as a result of manufacturing the bonded substrate, no bonding inhibition occurred and a bonded substrate was obtained that was normally bonded.

[Example 7]
Next, Example 7 was conducted. In Example 7, tests and evaluations were performed in the same manner as in Example 1, except that the thickness of the adhesive was set to 450 μm by stacking three sheets of adhesive. As a result of calculating the increase rate of the number of particles from the initial state, the increase rate was twice. Further, the influence on the degree of vacuum was rated C. Furthermore, as a result of manufacturing the bonded substrate, no bonding inhibition occurred and a bonded substrate was obtained that was normally bonded.

[Example 8]
Next, Example 8 was conducted. In Example 8, tests and evaluations were conducted in the same manner as in Example 2, except that the thickness of the adhesive was set to 450 μm by stacking three sheets of adhesive. As a result of calculating the rate of increase in the number of particles from the initial state, the rate of increase was three times. Further, the influence on the degree of vacuum was rated C. Furthermore, as a result of manufacturing the bonded substrate, no bonding inhibition occurred and a bonded substrate was obtained that was normally bonded.

[Example 9]
Next, Example 9 was conducted. In Example 9, tests and evaluations were conducted in the same manner as in Example 3, except that the thickness of the adhesive was set to 450 μm by stacking three sheets of adhesive. As a result of calculating the increase rate of the number of particles from the initial state, the increase rate was 5 times. Moreover, the influence on the degree of vacuum was evaluated as B. Furthermore, as a result of manufacturing the bonded substrate, no bonding inhibition occurred and a bonded substrate was obtained that was normally bonded.

[Comparative example 1]
Next, Comparative Example 1 was conducted. An irradiation test was conducted in the same manner as in Example 1 except that a cathode member not covered with an adhesive material was used as the cathode member. As a result of calculating the increase rate of the number of particles from the initial state, the increase rate was 20 times. Further, as a result of manufacturing the bonded substrate, bonding inhibition occurred, and fractured portions were observed in the obtained bonded substrate.

[Comparative example 2]
Next, Comparative Example 2 was conducted. The cathode was a cathode 100C shown in FIG. 6, and (bottom surface 110C, top surface 120C, side surfaces 130C, 140C, 150C, and 160C) were used as cathode members. The cathode member is coated with an adhesive material 104C as shown in the drawing. In addition, the area ratio of the area covered with the adhesive material (area covered with the adhesive material/area of the entire surface of the cathode member) was 83.7%. An irradiation test was conducted in the same manner as in Example 1 except for the cathode member. The influence on the degree of vacuum was rated D, and although a product was obtained, the efficiency of surface treatment was extremely poor and productivity was difficult.

[Comparative example 3]
Next, Comparative Example 3 was conducted. The cathode was a cathode 100D shown in FIG. 7, and (bottom surface 110D, top surface 120D, side surfaces 130D, 140D, 150D, 160D) were used as cathode members. The cathode member is coated with an adhesive material 104D as shown in the drawing. Further, the area ratio of the area covered with the adhesive material (area covered with the adhesive material/area of the entire surface of the cathode member) was 1.9%. An irradiation test was conducted in the same manner as in Example 1 except for the cathode member. As a result of calculating the increase rate of the number of particles from the initial state, the increase rate was 18 times. Moreover, the influence on the degree of vacuum was rated A. Further, as a result of manufacturing the bonded substrate, bonding inhibition occurred, and fractured portions were observed in the obtained bonded substrate.

[Comparative example 4]
Next, Comparative Example 4 was conducted. Comparative Example 4 was tested and evaluated in the same manner as in Example 1, except that the thickness of the adhesive was 600 μm by stacking four sheets of adhesive. The influence on the degree of vacuum was rated D, and although a product was obtained, the efficiency of surface treatment was extremely poor and productivity was difficult.

[Comparative example 5]
Next, Comparative Example 5 was conducted. Comparative Example 5 was tested and evaluated in the same manner as in Example 3, except that the thickness of the adhesive was set to 600 μm by stacking four sheets of adhesive. The influence on the degree of vacuum was rated D, and although a product was obtained, the efficiency of surface treatment was extremely poor and productivity was difficult.

In Examples 1 to 9, which are exemplary embodiments of the present invention, in Comparative Examples 1 and 3, the areas in the cathode member where particles generated due to the sputtering phenomenon tend to accumulate were coated with an adhesive material having adhesive properties. The rate of increase in the number of particles was lower compared to the previous model, indicating that particle emission could be suppressed. In addition, by setting the area ratio of the adhesive material to 5% to 80% and the thickness to 500 μm or less, it is possible to suppress a decrease in the efficiency of surface treatment due to a decrease in the degree of vacuum in the fast atomic beam source, and to suppress the decrease in the efficiency of surface treatment. The manufacturing efficiency of the substrate can be increased.

100 Cathode 101 Particle beam discharge port 102 Gas inlet port 104 Adhesive material 103 Cathode member 103a Corner portion 110 Bottom surface 120 Top surface 130 Side surface 140 Side surface 150 Side surface 160 Side surface 200 Anode 500 Fast atomic beam source 700 Bonded substrate 710 First semiconductor substrate 720 Second semiconductor substrate 711, 721 Surface to be bonded

Claims (9)

A cathode of a fast atomic beam source,
The cathode has a box shape with six inner surfaces and is hollow inside,
The six inner surfaces include a bottom surface, a top surface facing the bottom surface, and four side surfaces connecting the bottom surface and the top surface, and the six inner surfaces are composed of six flat cathode members. is,
The four side surfaces are opposite to each other and are parallel to each other,
Of the four side surfaces, one of the two pairs of opposing side surfaces is provided with an inert gas inlet for introducing an inert gas into the cathode, and the other is provided with an inert gas inlet for introducing an inert gas into the cathode. is equipped with a particle beam emission port that emits a high-speed atomic beam.
The cathode member has a shape whose outline is composed of four corner parts and four sides connecting the corner parts,
In the plane of the cathode member constituting the inner surface of the cathode, the cathode member has an adhesive covering area covered with an adhesive;
The adhesive material coated area is an area where the amount of re-deposition of sputtered dust generated by the sputtering is larger than the amount of the cathode member removed by sputtering generated by using the high-speed atomic beam source,
The area covered with the adhesive material has an area ratio of 5% to 80% of the area of the entire inner surface,
The thickness of the adhesive material is 500 μm or less,
The cathode, wherein the surface of the adhesive material exposed on the inner surface of the cathode has an adhesive force of 5N/25mm to 15N/25mm. The cathode according to claim 1, wherein the adhesive coated area includes the corner portion. The cathode according to claim 1, wherein the cathode member is made of graphite, glassy carbon, silicon, or silicon carbide. A cathode according to claim 1;
A high-speed atomic beam source, comprising: an anode provided inside the cathode. A method for manufacturing a bonded substrate in which a first semiconductor substrate and a second semiconductor substrate are stacked, the method comprising:
An irradiation step of irradiating a surface to be bonded of the first semiconductor substrate and a surface to be bonded of the second semiconductor substrate with a high-speed atomic beam in a vacuum using the high-speed atomic beam source according to claim 4. and,
a contact step of contacting the surface to be bonded of the first semiconductor substrate and the surface to be bonded of the second semiconductor substrate irradiated with the high-speed atomic beam to obtain a laminate having a bonding interface;
A method for manufacturing a bonded substrate, comprising: The method for manufacturing a bonded substrate according to claim 5, further comprising a heat treatment step of heat-treating the laminate obtained in the bonding step to obtain a bonded substrate. 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, The method for manufacturing a bonded substrate according to claim 5. The method for manufacturing a bonded substrate according to claim 5, wherein the high-speed atomic beam contains any one of argon, neon, and xenon. A method for regenerating the cathode according to claim 1, comprising:
an adhesive material removal step of removing the adhesive material from the adhesive material coated region of the cathode member constituting the cathode after being used in the fast atomic beam source;
A method for recycling a cathode, comprising the step of coating the adhesive-coated area of the cathode member from which the adhesive has been removed with a new adhesive.

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