JP2019156659A - MANUFACTURING METHOD OF SiC INGOT MANUFACTURING SUBSTRATE, AND SiC INGOT MANUFACTURING SUBSTRATE - Google Patents

Abstract

To provide a SiC ingot manufacturing substrate formed by bonding, without using an adhesive, a SiC substrate on which a SiC ingot is deposited to a support substrate to which the SiC substrate is bonded.SOLUTION: A manufacturing method of a SiC ingot manufacturing substrate includes a formation step for forming a SiC intermediate layer on at least either of joining schedule surfaces for joining a SiC substrate on which a SiC crystal is formed to a support substrate for supporting the SiC substrate, and a joining step for joining the SiC substrate to the support substrate through the SiC intermediate layer by pressing the SiC substrate and the support substrate mutually.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a substrate for manufacturing a SiC ingot and a substrate for manufacturing a SiC ingot.

  Usually, after a SiC (silicon carbide) substrate and a graphite (graphite) substrate as a base material are bonded together, vaporized SiC molecules are vapor-deposited on the surface of the SiC substrate in a chamber to manufacture a SiC ingot. For example, Patent Document 1 discloses a method of manufacturing an SiC ingot by growing an SiC crystal on a seed crystal substrate made of SiC to which a graphite substrate is bonded.

JP 2016-13949 A

  After the SiC ingot is manufactured, the SiC substrate and the graphite substrate are peeled off. Generally, the temperature in the chamber when manufacturing the SiC ingot is 2300 ° C. or higher, and it takes 200 hours or more to complete the SiC ingot. Usually, an adhesive having excellent heat resistance is used for bonding the SiC substrate and the graphite substrate. However, if the temperature required for manufacturing the ingot is applied for a long time, there is a problem that the physical properties of the adhesive change.

  In addition, when there is a pinhole-like defect between the SiC substrate and the graphite substrate during bonding with the adhesive, the gas residue inside the pinhole expands due to heat due to the high temperature during ingot production, and the SiC substrate and the graphite substrate May peel off.

  This invention is made in view of the above, Comprising: The SiC ingot manufacture which can adhere | attach the SiC substrate in which a SiC ingot is vapor-deposited, and the support substrate to which a SiC substrate is adhere | attached, without using an adhesive agent An object of the present invention is to provide a method for manufacturing a substrate and a substrate for manufacturing a SiC ingot.

  In order to solve the above-described problems and achieve the object, a manufacturing method of a substrate for manufacturing an SiC ingot according to the present invention is a bonding plan in which an SiC substrate on which an SiC crystal is formed and a support substrate that supports the SiC substrate are bonded Forming a SiC intermediate layer on at least one of the surfaces; and a bonding step of pressing the SiC substrate and the support substrate together to bond the SiC substrate and the support substrate through the SiC intermediate layer. Features.

  Moreover, according to one aspect of the present invention, the method further includes a peeling step of peeling the SiC substrate and the support substrate.

  Moreover, according to one aspect of the present invention, an ingot forming step of forming SiC ingots by depositing SiC molecules on a SiC substrate after the bonding step and before the peeling step is provided.

  According to another aspect of the present invention, in the above manufacturing method, the support substrate is a graphite (graphite) substrate or a SiC substrate.

  Moreover, according to one aspect of the present invention, in the manufacturing method, a plurality of SiC intermediate layers are formed in the forming step.

  Moreover, according to one aspect of the present invention, in the above manufacturing method, before the bonding step, at least one of the planned bonding surfaces of the SiC substrate or the support substrate is activated by irradiating particles having predetermined kinetic energy. And a surface activation step.

  Moreover, according to one aspect of the present invention, in the above manufacturing method, a surface activation step of activating the surface of the SiC intermediate layer by irradiating particles having a predetermined kinetic energy before the bonding step is further performed. Prepare.

  Moreover, according to one aspect of the present invention, in the manufacturing method described above, a part of the substrate bonding planned surface is selectively surface activated before the bonding step.

  Moreover, according to one aspect of the present invention, in the above manufacturing method, at least one of the planned bonding surfaces of the SiC substrate and the support substrate is exposed to a gas atmosphere containing an inert gas before the bonding step.

  According to one embodiment of the present invention, in the manufacturing method, the inert gas is nitrogen, argon, or a mixed gas thereof.

  According to one embodiment of the present invention, in the above manufacturing method, the joining step is performed in a vacuum atmosphere or an inert gas atmosphere.

  According to one embodiment of the present invention, in the above manufacturing method, the inert gas in the inert gas atmosphere in which the bonding step is performed is nitrogen, argon, or a mixed gas thereof.

According to one embodiment of the present invention, in the above manufacturing method, the joining step is performed in a vacuum or a reduced pressure atmosphere in which the background pressure is 1 × 10 ⁻⁸ Pa or more and less than atmospheric pressure.

  Moreover, according to 1 aspect of this invention, the board | substrate for SiC ingot manufacture manufactured by said manufacturing method is provided.

  According to the present invention, since the SiC substrate on which the SiC ingot is deposited and the support substrate to which the SiC substrate is bonded can be bonded without using an adhesive, the SiC substrate is exposed to a high temperature required for manufacturing the SiC ingot for a long time. However, there is no deterioration such as generation of voids in the joint surface between the SiC substrate and the support substrate, and there is an effect that there is no fear of peeling between the SiC substrate and the support substrate.

It is a figure explaining the manufacturing method of the board | substrate for SiC ingot manufacture which concerns on this Embodiment. It is a figure explaining an example of the process of growing a SiC crystal after a joining process. It is a figure explaining the process of the manufacturing method of the substrate for SiC ingot manufacture concerning other Embodiment 1. FIG. It is a figure explaining the process of the manufacturing method of the substrate for SiC ingot manufacture concerning other Embodiment 2. FIG. It is the photograph which image | photographed the joint surface of the conjugate | zygote which concerns on the Example of this invention.

  Hereinafter, the present invention will be described with reference to embodiments, but it is obvious that the present invention is not limited to these specific embodiments.

[Embodiment 1]
The manufacturing method of the present embodiment is a manufacturing method of a substrate for manufacturing an SiC ingot, and an SiC substrate on which SiC substrates on which an SiC crystal is formed and a support substrate that supports the SiC substrate are bonded to at least one of the surfaces to be bonded. A forming step of forming the intermediate layer, and a bonding step of pressing the SiC substrate and the support substrate together to bond the SiC substrate and the support substrate through the SiC intermediate layer.

  In the manufacturing method having the above-described configuration, the bonding surface is deteriorated even when heat treatment at 2300 ° C. or higher is performed in the process after bonding the substrate by bonding the SiC substrate and the support substrate through the SiC intermediate layer. In addition, the substrate and the supporting substrate can be easily peeled later. Alternatively, depending on the material and conditions, there is a possibility that the SiC substrate and the support substrate can be easily peeled even if heat treatment is performed at a higher temperature.

  FIG. 1 is a view for explaining an example of a method for producing a substrate for producing an SiC ingot according to the present embodiment. In this example, a SiC substrate 1 on which a SiC crystal is formed and a support substrate 2 that supports the SiC substrate 1 are bonded together via a SiC intermediate layer 3 formed on the support substrate 2, so that a SiC ingot is obtained. The form by which the board | substrate for manufacture is manufactured is shown.

(A) SiC substrate and supporting substrate preparation step An SiC substrate 1 on which an SiC crystal is formed and a supporting substrate 2 that supports the substrate are prepared.
(B) SiC intermediate layer forming step The SiC intermediate layer 3 is formed on the planned bonding surface of the support substrate 2 to which the SiC substrate 1 is bonded.
(C) Substrate Bonding Step The SiC substrate 1 and the support substrate 2 are pressed against each other, and the SiC substrate and the support substrate are bonded via the SiC intermediate layer 3 to form a substrate bonded body. As a result, an SiC ingot manufacturing substrate is manufactured.

  FIG. 2 is a diagram for explaining an example of a process for growing a SiC crystal on a SiC ingot manufacturing substrate.

(D) SiC epitaxial growth process The SiC-containing source gas 4 for epitaxial growth is made to contact and flow on the surface opposite to the joint surface with the support substrate 2.
(E) Formation of SiC Ingot SiC is formed on the SiC substrate 1 by epitaxial growth, and a SiC ingot 5 made of SiC formed by the SiC substrate 1 and epitaxial growth is formed.

  In the above manufacturing method, the support substrate 2 may be a graphite (graphite) substrate or a SiC substrate.

  In the above manufacturing method, a surface activation step described later may be further provided between the step (b) and the step (c).

  The manufacturing method further includes a surface activation step of activating at least one of the planned bonding surfaces of the SiC substrate 1 or the support substrate 2 by irradiating particles having a predetermined kinetic energy before the bonding step. Also good.

  Or in the said manufacturing method, you may further provide the surface activation process of activating the surface of SiC intermediate layer 3 by irradiating the particle | grains provided with predetermined | prescribed kinetic energy before a joining process.

  By the surface activation process in the surface activation process, the bonding strength at the bonding interface between the SiC substrate 1 or the SiC intermediate layer 3 formed on the support substrate 2 can be increased in the substrate bonding process.

  By causing particles having a predetermined kinetic energy to collide and causing the material that forms the bonding surface to physically repel (sputtering phenomenon), the surface layer such as oxides and contaminants is removed, and the surface energy An emerging surface of high or active inorganic material can be exposed.

  As particles used for the surface activation treatment, for example, a rare gas or an inert gas such as neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), or helium (He) can be employed. These rare gases are unlikely to cause a chemical reaction with a substance that forms a collision surface to be collided, so that a chemical property of the bonding surface is not greatly changed by forming a compound or the like.

  Particles that collide with the surface to be surface activated can be given a predetermined kinetic energy by accelerating the particles toward the surface using a particle beam source or a plasma generator.

  It is preferable that the kinetic energy of the particles colliding with the surface to be surface activated is 1 eV to 2 keV. It is considered that the above kinetic energy efficiently causes a sputtering phenomenon in the surface layer. A desired value of kinetic energy can also be set from the above kinetic energy range according to the thickness of the surface layer to be removed, the properties such as the material, the material of the new surface, and the like.

A particle beam source can also be used to impart a predetermined kinetic energy to the particles. The particle beam source operates in a relatively high vacuum, such as a background pressure of 1 × 10 ⁻⁸ Pa (pascal) or less. The substance removed from the surface of the metal region is efficiently exhausted out of the atmosphere by the operation of the vacuum pump to draw a relatively high vacuum.

  Thereby, adhesion of the undesirable substance to the exposed new surface can be suppressed. Furthermore, since the particle beam source can apply a relatively high acceleration voltage, high kinetic energy can be imparted to the particles. Therefore, it is considered that the surface layer can be efficiently removed and the nascent surface can be activated.

Alternatively, the surface activation treatment may be performed in a vacuum or reduced pressure atmosphere in which the background pressure is 1 × 10 ⁻⁸ Pa or more and less than atmospheric pressure.

  As the particle beam source, an ion beam source that emits an ion beam or a neutral atom beam source that emits a neutral atom beam can be used. As the ion beam source, a cold cathode ion source can be used.

  As the neutral atom beam source, a fast atom beam source (FAB, Fast Atom Beam) can be used. A fast atom beam source (FAB) generates a typical plasma for peeling off a surface layer, applies an electric field to the plasma, extracts positive ions of particles ionized from the plasma, and passes them through an electron cloud. It has a structure that is neutralized.

  In this case, for example, when argon (Ar) is used as the rare gas, the power supplied to the fast atom beam source (FAB) may be set to 1.5 kV (kilovolt), 15 mA (milliampere), or 0.1 To a value between 500 W (watts). For example, when a fast atom beam source (FAB) is operated from 100 W (watts) to 200 W (watts) and irradiated with a fast atom beam of argon (Ar) for about 2 minutes, the oxide, contaminants, etc. (surface) Layer) can be removed to expose the nascent surface.

  In the present invention, the particles used for surface activation may be neutral atoms or ions, may be radical species, and may be a particle group in which these are mixed.

  Depending on the operating conditions of each plasma or beam source, or the kinetic energy of the particles, the removal rate of the surface layer can vary. Therefore, it is necessary to adjust the treatment time required for the surface activation treatment.

  For example, the presence of oxygen and carbon contained in the surface layer is confirmed using surface analysis methods such as Auger Electron Spectroscopy (AES) and X-ray Photoelectron Spectroscopy (XPS). You may employ | adopt the time which becomes impossible or longer than it as the processing time of a surface activation process.

A predetermined kinetic energy can also be given to particles using a plasma generator. By applying an alternating voltage to the bonding surface of the substrate, a plasma containing particles is generated around the bonding surface, and the cations of the ionized particles in the plasma are accelerated toward the bonding surface by the voltage. Thus, given kinetic energy is given.
Since the plasma can be generated in an atmosphere with a low degree of vacuum of about several pascals (Pa), the vacuum system can be simplified and the steps such as evacuation can be shortened.

  In the above manufacturing method, a surface activation process may be selectively performed on the substrate surface before the bonding step of bonding the SiC substrate 1 and the support substrate 2. Moreover, you may selectively surface-activate to a part of SiC intermediate | middle layer 3 before a joining process.

  Part of SiC intermediate layer 3 is, for example, the outer peripheral portion of SiC substrate 1, and the surface activation treatment is performed only on the outer peripheral portion, so that the bonding force of the outer peripheral portion is increased with respect to the central portion of SiC substrate 1. preferable.

  The support substrate 2 preferably has a thickness of 0.1 mm or more and 1.1 mm or less from the viewpoint that an existing facility can be used.

  The SiC intermediate layer 3 is preferably formed by a deposition method such as plasma enhanced chemical vapor deposition (PECVD), sputter deposition, or ion beam sputtering, but is not limited thereto. When the SiC intermediate layer 3 is formed, it can be formed only in a predetermined region by using a predetermined mask.

  It is preferable that the film thickness and film quality of SiC intermediate layer 3 used for bonding SiC substrate 1 and support substrate 2 are adjusted so that they can be easily peeled off after a heating process, a cleaning process, and the like.

  The thickness of SiC substrate 1 is preferably not less than 0.5 μm and not more than 0.5 mm, and more preferably not less than 0.5 μm and not more than 0.2 mm.

In the manufacturing method according to the above-described embodiment, the substrate bonding step may be performed in a vacuum atmosphere or an inert gas atmosphere. Thereby, the joining strength between SiC substrate 1 and support substrate 2 can be easily controlled. The inert gas may be nitrogen (N ₂ ), helium (He), neon (Ne), argon (Ar), or the like alone or a mixed gas in which any of these is combined.

In the manufacturing method according to the above embodiment, before the substrate bonding step, the bonding surface between the SiC substrate 1 and the support substrate 2 is exposed to an inert gas atmosphere. Thereby, the change in the bonding strength between SiC substrate 1 and support substrate 2 due to heating is unlikely to occur. The inert gas may be nitrogen (N ₂ ), helium (He), neon (Ne), argon (Ar), or the like alone or a mixed gas in which any of these is combined.

In the manufacturing method according to the embodiment, the substrate bonding step may be performed in a vacuum or a reduced pressure atmosphere in which the background pressure is 1 × 10 ⁻⁸ Pa or more and less than atmospheric pressure.

  By controlling the basic vacuum, moisture and oxygen contained in the SiC intermediate layer 3 can be controlled appropriately. The SiC intermediate layer 3 having appropriately controlled moisture and oxygen amounts does not increase the bonding strength even during heating, and is easy to peel off.

  Further, for example, the substrates may be joined without going through the above-described surface activation process. For example, the SiC intermediate layer 3 formed by vapor deposition or the like in a vacuum is in a state where the surface energy is high because oxidation or contamination due to impurities does not proceed on the surface. By bringing the surfaces of the SiC intermediate layer 3 into contact with each other, a relatively strong bonding interface can be formed.

[Other embodiment 1]
With reference to FIG. 3, another embodiment 1 is shown. In the present embodiment, the SiC intermediate layer 3 is formed on the bonding surfaces of both the SiC substrate 1 and the support substrate 2 as shown in FIG. Only the points described above are different, and the other steps are the same as those in the first embodiment.

[Other embodiment 2]
Another embodiment 2 is shown with reference to FIG. In this embodiment, in the SiC intermediate layer forming step of FIG. 3F of the second embodiment, a plurality of SiC intermediate layers 3 are formed on the bonding surfaces of both the SiC substrate 1 and the support substrate 2 as shown in FIG. However, the other steps are the same as those in the first embodiment. In this figure, two SiC intermediate layers 3 are formed, but any number of layers may be formed.

  Although the embodiments of the present invention have been described above, it is obvious that the present invention includes combinations of the configurations of these embodiments.

  Examples are shown below.

[Example]
The test of the Example was performed in the following procedures.
(1) Preparation of SiC substrate (support substrate) Assuming a support substrate, an SiC substrate having a thickness of 0.5 mm was prepared.

(2) Preparation of SiC substrate (SiC epitaxial growth substrate) An SiC substrate having a thickness of 0.5 mm was prepared as the SiC substrate.

(3) Formation of SiC intermediate layer Using ion beam sputtering, the SiC intermediate layer was formed on both surfaces of the surface on which the support substrate and the SiC substrate are bonded. The input value of the ion beam at this time was 1.3 Kv / 400 mA.

(4) Room temperature bonding treatment Room temperature bonding treatment was performed under the following conditions.
(Normal temperature bonding conditions)
5.0kN, 5min

  It was able to join without any problem under the above conditions. (Fig. 5)

  Although various embodiments of the present invention have been described above, the above description is not intended to limit the present invention, and various modifications including deletion, addition, and replacement of components are included in the technical scope of the present invention. Conceivable.

DESCRIPTION OF SYMBOLS 1 Support substrate 2 SiC substrate 3 SiC intermediate layer 4 SiC containing epitaxial growth source gas 5 SiC ingot (after epitaxial growth)

Claims (14)

A forming step of forming a SiC intermediate layer on at least one of bonding planned surfaces where a SiC substrate on which a SiC crystal is formed and a support substrate that supports the SiC substrate are bonded;
A bonding step of pressing the SiC substrate and the support substrate together to bond the SiC substrate and the support substrate via the SiC intermediate layer;
A method for manufacturing a substrate for manufacturing a SiC ingot, comprising:   The method for producing a substrate for producing a SiC ingot according to claim 1, further comprising a peeling step of peeling the SiC substrate and the support substrate.   3. The SiC ingot manufacturing substrate according to claim 2, further comprising an ingot forming step of forming SiC ingots by depositing SiC molecules on the SiC substrate after the bonding step and before the peeling step. Manufacturing method.   The method of manufacturing a substrate for manufacturing a SiC ingot according to any one of claims 1 to 3, wherein the support substrate is a graphite (graphite) substrate or a SiC substrate.   5. The method for manufacturing a substrate for manufacturing a SiC ingot according to claim 1, wherein a plurality of SiC intermediate layers are formed in the forming step. 6.   The method further comprises a surface activation step of activating at least one surface to be bonded of the SiC substrate or the support substrate by irradiating particles having a predetermined kinetic energy before the bonding step. The manufacturing method of the board | substrate for SiC ingot manufacture as described in any one of 1 to 5.   7. The method according to claim 1, further comprising a surface activation step of activating the surface of the SiC intermediate layer by irradiating particles having predetermined kinetic energy before the bonding step. The manufacturing method of the board | substrate for SiC ingot manufacture as described in a term.   The method for manufacturing a substrate for manufacturing an SiC ingot according to any one of claims 1 to 7, wherein a part of the substrate bonding planned surface is selectively surface activated before the bonding step.   The SiC ingot according to any one of claims 1 to 8, wherein at least one of the surfaces to be bonded of the SiC substrate and the support substrate is exposed to a gas atmosphere containing an inert gas before the bonding step. A method for manufacturing a manufacturing substrate.   The method for manufacturing a substrate for manufacturing a SiC ingot according to claim 9, wherein the inert gas is nitrogen, argon, or a mixed gas thereof.   The manufacturing method of the substrate for SiC ingot manufacture as described in any one of Claim 1 to 10 with which a joining process is performed in a vacuum atmosphere or inert gas atmosphere.   The method for producing a substrate for producing an SiC ingot according to claim 11, wherein the inert gas is nitrogen, argon, or a mixed gas thereof. The production of a substrate for producing an SiC ingot according to any one of claims 1 to 12, wherein the bonding step is performed in a vacuum or a reduced pressure atmosphere in which a background pressure is 1 x ^10-8 Pa or more and less than atmospheric pressure. Method. A SiC ingot manufacturing substrate manufactured by the manufacturing method according to claim 1.