JP2021155813A - Film deposition support substrate and method for manufacturing polycrystal substrate - Google Patents

Abstract

To provide a film deposition support substrate capable of easily separating a laminate having a desired size from a laminate of a support substrate and a film deposited by a chemical vapor deposition method, reducing a period of time required for separation to improve production efficiency and suppressing the wear of a separation tool to reduce cost by the longer life of the separation tool, and a method for manufacturing a polycrystal substrate using the same.SOLUTION: A surface to be deposited by a chemical vapor deposition method includes: a part to be deposited separated after film deposition; slits intermittently provided along the shape of the part to be deposited and penetrated in the thickness direction of the film deposition support substrate; and a connection part positioned between the slits and having a length of 1-10 mm.SELECTED DRAWING: Figure 1

Description

The present invention relates to a support substrate for film formation and a method for manufacturing a polycrystalline substrate.

Silicon carbide (hereinafter, may be referred to as "SiC") has a large band gap (4H-SiC, which is about 3 times larger than that of silicon (hereinafter, may be referred to as "Si"). It has a high thermal conductivity (about 5 W / cm · K, about 1.5 W / cm · K) and high thermal conductivity (about 3.8 eV, about 3.1 eV for 6H-SiC, about 1.1 eV for Si). For this reason, in recent years, single crystal silicon carbide has begun to be used as a substrate material for power device applications.

For example, compared to the conventionally used Si power device, the SiC power device realizes a withstand voltage that is about 5 to 10 times larger and an operating temperature that is several hundred degrees higher, and further reduces the power loss of the element to about 1/10. Since it can be reduced, it has been put into practical use in inverters for railway vehicles and the like.

Usually, the silicon carbide single crystal substrate is produced by a vapor phase method called a sublimation recrystallization method (improved Rayleigh method) (see, for example, Non-Patent Document 1), and is processed to a desired diameter and thickness.

In the improved Rayleigh method, a solid silicon carbide raw material (usually in powder form) is heated and sublimated at a high temperature (about 2,400 ° C or higher), and sublimated silicon atoms and carbon atoms in an inert gas atmosphere are 2, This is a production method in which massive single crystal silicon carbide is grown by being transported by diffusion as vapor at 400 ° C., supersaturated and recrystallized on a seed crystal placed at a temperature lower than that of the raw material.

However, in this improved Rayleigh method, since the process temperature is as high as 2,400 ° C. or higher, it is very difficult to control the temperature of crystal growth, convection control, and crystal defects. Therefore, since the single crystal silicon carbide substrate produced by this method may have many crystal defects called micropipes and other crystal defects (lamination defects, etc.), high-quality crystals that can withstand electronic device applications. It is extremely difficult to manufacture the substrate with good yield.

As a result, a high-quality silicon carbide single crystal substrate that can be used for electronic devices and has few crystal defects becomes very expensive, and a device using such a silicon carbide single crystal substrate is also expensive. It was. This has hindered the widespread use of silicon carbide single crystal substrates.

Therefore, in recent years, a silicon carbide single crystal substrate and a silicon carbide polycrystal substrate are prepared, and a step of bonding the silicon carbide single crystal substrate and the silicon carbide polycrystal substrate is performed, and then the silicon carbide single crystal substrate is thinned. It has been proposed to carry out a step of converting silicon carbide to produce a substrate in which a silicon carbide single crystal thin plate layer is formed on a silicon carbide polycrystal substrate (see, for example, Non-Patent Document 2).

According to this manufacturing method, the thickness of the silicon carbide single crystal substrate can be reduced from a fraction to a hundredth of that of the conventional one, and therefore, all of the silicon carbide substrates are expensive as in the conventional case. In addition, the cost of the silicon carbide substrate can be significantly reduced as compared with the case of being composed of a high-quality silicon carbide single crystal. Further, since an element such as a power device can be formed on a high-quality silicon carbide single crystal layer having few crystal defects, it is possible to greatly improve device performance and manufacturing yield.

In the step of bonding the silicon carbide single crystal substrate and the silicon carbide polycrystalline substrate, the silicon carbide polycrystalline substrate is required to be dense, highly pure, and have high flatness. Therefore, a chemical vapor deposition method (hereinafter, may be referred to as “CVD method”) is used for manufacturing the silicon carbide polycrystalline substrate.

Patent Document 1 describes a method for producing a silicon carbide polycrystalline substrate using a chemical vapor deposition method (CVD method). According to this, silicon carbide can be deposited on the surface of a graphite-supporting substrate by a CVD method, a film is formed to a desired film thickness, and then the graphite-supporting substrate can be removed to obtain a silicon carbide polycrystal. The obtained silicon carbide polycrystal is denser and more pure than the silicon carbide polycrystal produced by the sintering method, and is also excellent in corrosion resistance, heat resistance, and strength characteristics.

Yu. M. Tairov and V. F. Tsvetkov: J.M. of Cryst. Growth, 43 (1978) p. 209 Journal of Precision Engineering, 2017, Vol. 83, No. 9, p. 833-836

Japanese Unexamined Patent Publication No. 8-26714

Here, as an example of a method of forming a polycrystalline film of silicon carbide or the like on a graphite support substrate and then removing the graphite support substrate to manufacture the polycrystalline substrate, the polycrystalline film is formed. From the laminate of the polycrystalline film and the graphite-based support substrate thus obtained, a method of removing the graphite-based support substrate from the laminate separated into a desired size to obtain a polycrystalline substrate can be considered.

When a polycrystalline substrate is produced by this method, especially in the case of silicon carbide having a Vickers hardness of 24 GPa, which is very hard, it takes a long time to separate and the tool for separation becomes very worn. There is a problem that the cost in the separation process becomes high.

Therefore, in the present invention, paying attention to the above-mentioned problems, it is easy to separate a laminate of a desired size from the laminate of the support substrate and the film formed by the chemical vapor phase deposition method, and the separation can be achieved. A support substrate for film formation, which can shorten the time required, improve production efficiency, suppress wear of the separation tool, and reduce the cost by extending the life of the separation tool, and a support substrate using the same. It is an object of the present invention to provide a method for manufacturing a polycrystalline substrate.

The film-forming support substrate of the present invention includes a film-forming target surface to be filmed by a chemical vapor vapor deposition method, and the film-forming target surface includes a film-forming target portion separated after film formation and the above-mentioned film formation target surface. It has a slit that is intermittently provided along the outer shape of the film target portion and penetrates in the thickness direction of the film-forming support substrate, and a connecting portion located between the slits. The length dimension is 1 mm to 10 mm.

In the film-forming support substrate of the present invention, two or more of the connection portions may be provided.

In the film-forming support substrate of the present invention, the width dimension of the slit may be 2 mm to 10 mm.

In the film-forming support substrate of the present invention, the film-forming support substrate is a support substrate for separating the film-forming target portion after film formation to obtain a circular substrate, and the film-forming target portion is It is circular in a plan view, and the diameter dimension of the film forming target portion may be 1 mm to 3 mm larger than the diameter dimension of the circular substrate.

In the film-forming support substrate of the present invention, the film-forming target portions may be formed at a plurality of locations so as not to overlap on the film-forming target surface.

In the film-forming support substrate of the present invention, the connection portion may be provided with a groove formed in the thickness direction.

In the film-forming support substrate of the present invention, the cross-sectional shape of the groove may be rectangular.

In the film-forming support substrate of the present invention, the connection portion may have a plurality of through holes formed in a perforation shape along the length direction.

The method for manufacturing a polycrystalline substrate of the present invention is a method for manufacturing a polycrystalline substrate using the support substrate for film formation of the present invention, in which a chemical vapor phase is formed on the surface of the support substrate for film formation to be formed. From the laminate of the support substrate for film formation and the polycrystalline film on which the polycrystalline film is formed by the vapor deposition method, the inside of the slit is separated at the portion of the slit to obtain a polycrystalline substrate intermediate. It includes a separation step and a removal step of removing the film-forming support substrate from the polycrystalline substrate intermediate to obtain a polycrystalline substrate.

In the method for producing a polycrystalline substrate of the present invention, even if the film formation target portion has a circular shape in a plan view and the slit is cut with a core drill in the separation step to separate the inside of the slit. good.

In the case of the support substrate for film formation of the present invention, when the film is formed by the chemical vapor deposition method, the portion where the slit is formed has a portion penetrating in the thickness direction or a slit is formed. The film is thinner than the non-existent part. Therefore, as compared with the support substrate for film formation in which no slit is formed, it is easier to separate the laminate of the film-forming target portion and the film-formed film after film formation, and the time required for separation is shortened for production. The efficiency can be improved, the wear of the separation tool can be suppressed, and the cost can be reduced by extending the life of the separation tool.

Further, according to the method for producing a polycrystalline substrate of the present invention, a film is formed on the film-forming support substrate of the present invention, and the inside of the slit is separated at the portion of the slit so that the slit is not formed. Compared with the film-supporting substrate, it is easier to separate the film-forming target portion and the film-forming film laminate from the film-forming support substrate and the film-formed film laminate. Therefore, the time required for separation is shortened, the production efficiency is improved, the wear of the separation tool is suppressed, and the cost can be reduced by extending the life of the separation tool.

(A) is a plan view showing the support substrate for film formation of the present embodiment, and (B) is a plan view showing the region P of FIG. 1 (A) in an enlarged manner. It is sectional drawing which shows typically an example of the film forming apparatus used in the manufacturing method of the silicon carbide polycrystalline substrate of this embodiment. In the cross section taken along line AA of FIG. 1, it is a cross-sectional view schematically showing a support substrate, a silicon carbide polycrystalline film, and a silicon carbide polycrystalline substrate in each step of the method for manufacturing a silicon carbide polycrystalline substrate of the present embodiment. .. It is sectional drawing of the laminated body of the support substrate for film formation after the silicon carbide polycrystalline film film formation, and the silicon carbide polycrystalline film in the cross section of FIG. 1 BB. (A) to (C) are cross-sectional views showing a modified example of the film-forming support substrate of the present embodiment in the cross-sectional view taken along the line AA of the region P of FIG. ) Is a plan view showing a modified example of the film-forming support substrate of the present embodiment. It is a top view which shows the modification of the support substrate for film formation of this embodiment. It is a top view which shows the modification of the support substrate for film formation of this embodiment.

A film-forming support substrate according to an embodiment of the present invention and a method for manufacturing a polycrystalline substrate using the film-forming support substrate will be described with reference to the drawings. The film-forming support substrate of the present embodiment can be used as a film-forming target for forming a polycrystalline film such as silicon carbide, titanium nitride, aluminum nitride, titanium carbide, and diamond-like carbon by a chemical vapor deposition method. .. Since it is effective when a polycrystalline film having a high hardness such as silicon carbide polycrystalline film is formed to produce a polycrystalline substrate, in the present embodiment, a silicon carbide polycrystalline film is formed to form a silicon carbide polycrystal. A case of manufacturing a crystalline substrate will be described as an example. The silicon carbide polycrystalline substrate produced by the method of the present embodiment can be used as a substrate for a power device by, for example, bonding it to a silicon carbide single crystal substrate.

[Support substrate for film formation]
The film-forming support substrate 100 of the present embodiment is made of graphite and has a silicon carbide polycrystalline film 200 formed on both sides, and is used for manufacturing the silicon carbide polycrystalline substrate 500 as described later. be able to. Further, as the film-forming support substrate 100, it is preferable to use a parallel flat plate, that is, as shown in the drawing, a parallel flat plate in which the film-forming target surfaces 110 and 120 correspond to the front surface and the back surface. can. In the present specification, "parallel" in the parallel flat plate includes not only strict parallelism but also a case where there is an unavoidable error in creating a parallel surface of the film-forming support substrate 100. The film-forming support substrate of the present embodiment is considered from the viewpoints of ease of removal of the film-forming support substrate in the removal step described later, workability for forming slits, cost of the film-forming support substrate itself, and the like. A graphite support substrate can be preferably used.

As shown in FIG. 1, the film-forming support substrate 100 has a film-forming target surface 110 for forming the silicon carbide polycrystal film 200 by a chemical vapor deposition method and a back surface with respect to the film-forming target surface 110. The film formation target surface 120, the four film formation target portions 130 separated after film formation, and the film formation target portions 130 are intermittently provided along the outer shape of each, and are provided intermittently along the outer shape of each of the film formation target portions 130 in the thickness direction of the film formation support substrate 100. A slit 140 penetrating the membrane and a connecting portion 150 located between the slits 140 are provided.

Further, in a plan view, the film-forming target portion 130 is a portion that is separated after the silicon carbide polycrystalline film 200 is formed to form the silicon carbide polycrystalline substrate intermediate 400, as will be described later.

Further, the film-forming support substrate 100 of the present embodiment is a support substrate for obtaining a circular substrate by separating the film-forming target portion after film-forming. In a plan view of the film-forming support substrate 100, as shown in FIG. 1, the film-forming target portions 130 provided on the film-forming support substrate 100 of the present embodiment are each circular and have the same shape and weight. It is formed at four locations on the film-forming support substrate 100 so as not to become.

The slit 140 is formed in an arc shape in which the outer shape of one film forming target portion 130 is substantially divided into four equal parts. A connecting portion 150 is provided between the four slits 140, and the film forming target portion 130 inside the slit 140 and the outside of the slit are connected and integrated.

The width dimension of the slit 140 (dimension L in FIG. 1B) is large enough not to be filled with the silicon carbide polycrystalline film 200 formed from both sides in the width direction of the slit 140 after the silicon carbide polycrystalline film 200 is formed. It is preferably formed. Further, if the width dimension of the slit 140 is too large, the film-forming support substrate 100 becomes too large, which is not preferable from the viewpoint of production cost. The width dimension of the slit 140 can be, for example, about 2 mm to 10 mm.

The slit 140 can be formed by processing a flat plate-shaped support substrate using, for example, a cutting machine equipped with a rotary blade or the like.

The length dimension of the connecting portion 150 (dimension M in FIG. 1B) is 1 mm to 10 mm. Further, the length dimension M of the connecting portion 150 is as short as possible within this numerical range so as to sufficiently support the film forming target portion 130 and to be easily separated after the silicon carbide polycrystalline film 200 is formed. The length is preferable.

The number of connecting portions 150 is not particularly limited, and may be one or a plurality as long as the film forming target portion 130 can be supported. However, it is preferable that the connection portion 150 is formed at two or more locations with respect to one film formation target portion 130 in order to sufficiently support the film formation target portion 130. Further, it is preferable that a plurality of connecting portions 150 are provided so as to be arranged at equal intervals on the outer periphery of the film forming target portion 130.

In the film forming support substrate 100 of this embodiment, four slits 140 and four connecting portions 150 are formed, but the number of slits 140 and connecting portions 150 is not limited to this embodiment and is one. It may be ~ 3, or 5 or more.

Further, the diameter dimension of the film forming target portion 130 can be made larger by about 1 mm to 3 mm than the diameter dimension (for example, 4 inches or 6 inches) of the silicon carbide polycrystalline substrate 500 to be manufactured. As a result, in the manufacturing process of the silicon carbide polycrystalline substrate 500, the diameter dimension is adjusted by removing the support substrate 100 for film formation and then grinding or polishing the outer peripheral portion, so that the silicon carbide polycrystal having a desired dimension is obtained. A crystalline substrate can be obtained. It is preferable that the size is sufficient to obtain the silicon carbide polycrystalline substrate 500 to be produced by separating the laminate of the silicon carbide polycrystalline film and the film-forming target portion. Further, if the size is significantly larger than the size of the silicon carbide polycrystalline substrate 500 to be manufactured, the processing load becomes too large when the outer peripheral portion is processed.

Further, since the film-forming target portion 130 is formed in a circular shape in a plan view and the slit 140 is formed along the outer shape of the film-forming target portion 130, the film-forming support substrate 100 and the silicon carbide polycrystalline film 200 The silicon carbide polycrystalline substrate intermediate 400 can be efficiently separated from the laminate 300 using a separation tool such as a core drill. Further, since the silicon carbide polycrystalline substrate 500 is usually manufactured in a circular shape, the burden of post-processing can be reduced as compared with the case where the slit 140 is not formed in a circular shape.

The slits 140 are formed at a plurality of locations (four locations in the present embodiment) so as not to overlap each other on the film formation target surface. Thereby, for example, in the case of the film-forming support substrate 100 of the present embodiment in which the film-forming target surfaces are both sides, one film-forming support substrate 100 to eight silicon carbide polycrystalline substrates 500 can be manufactured. It is possible to increase the manufacturing efficiency and reduce the manufacturing cost.

The film-forming support substrate 100 of the present embodiment is provided intermittently along the outer shape of the film-forming target portion 130, and has a slit 140 penetrating in the thickness direction and four connecting portions located between the slits 140. 150, and the length dimension of the connecting portion is 1 mm to 10 mm.

As a result, when the film is formed by the chemical vapor deposition method, the portion where the slit is formed has a portion penetrating in the thickness direction, or the film is thinner than the portion where the slit is not formed. ing. Therefore, as compared with the support substrate for film formation in which no slit is formed, it is easier to separate the laminate of the film-forming target portion and the film-formed film after film formation, and the time required for separation is shortened for production. The efficiency can be improved, the wear of the separation tool can be suppressed, and the cost can be reduced by extending the life of the separation tool.

The present invention is not limited to the above-described embodiment, but includes other steps and the like that can achieve the object of the present invention, and the following modifications and the like are also included in the present invention. In the following modified examples, the same components as those in the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted.

In the above-described embodiment, the connection portion 150 has not been processed or the like, but after the silicon carbide polycrystalline film is formed on the film-forming support substrate, the connection portion is connected so as to be easily separated. The part may be processed.

5 (A) to 5 (C) show a modified example of the film-forming support substrate of the above-described embodiment in the cross section taken along the line AA of FIG. It is sectional drawing which shows the substrate. The film-forming support substrate 100B shown in FIG. 5A is formed at the connection portion 150B from the film-forming target surface 110 toward the film-forming target surface 120, that is, in the thickness direction of the film-forming support substrate 100B. In addition, it has a groove 151 having a rectangular shape in cross section. The groove 151 having a rectangular cross section can be easily obtained by processing a film-forming support substrate having a slit 140 with a circular drill such as a core drill.

The film-forming support substrate 100C shown in FIG. 5B has a groove 152 formed from the film-forming target surface 110 toward the film-forming target surface 120 at the connection portion 150C. The groove 152 has a triangular shape in a cross-sectional view, and is formed so that the width gradually narrows from the film-forming target surface 110 toward the film-forming target surface 120.

The film-forming support substrate 100D shown in FIG. 5C has a groove 153 formed in the thickness direction from the film-forming target surface and the film-forming target surface 120 at the connection portion 150D, respectively. Each of the grooves 153 has a triangular shape in a cross-sectional view, and is formed so that the width gradually narrows from the film-forming target surfaces 110 and 120 toward the center in the thickness direction.

The shape of the groove formed in the connecting portion is not limited to the rectangular shape in the cross-sectional view or the triangular shape in the cross-sectional view, and may be another shape such as a polygonal shape in the cross-sectional view. If the shape of the groove is rectangular in cross section, it is more preferable because it can be easily processed by using a core drill. Further, as in the film forming support substrate 100D shown in FIG. 5C, grooves may be provided on both the front surface and the back surface of the film forming support substrate, or may be provided on only one side. May be good.

Further, FIG. 5 (D) is a plan view showing a modified example of the film-forming support substrate of the present embodiment in the region P of FIG. 1 (A). The film-forming support substrate 100E shown in FIG. 5D has perforated through holes formed in the connection portion 150E along the length direction of the connection portion 150E.

Like the above-mentioned film-forming support substrates 100B, 100C, 100D, and 100E, the silicon carbide polycrystalline film is formed by forming grooves and through holes at the connection portion of the film-forming support substrate, and then carbonized. It becomes easy to separate the silicon polycrystalline film and the laminate of the film-forming target portion. In addition, by adjusting the size of the grooves and through holes, it is possible to break and separate the laminated body of the silicon carbide polycrystalline film and the film formation target portion without using a cutting tool such as a cutting machine. Become. When it is cut off and separated, it is more preferable that a perforated through hole is formed from the viewpoint of ease of breaking off.

In the film-forming support substrate 100 of the present embodiment, the outer shape of the film-forming target portion 130 is formed in a circular shape, but the shape and size of the desired silicon carbide polycrystalline substrate are not particularly limited to a circular shape. Can be adjusted to.

For example, the film formation target portion may have a rectangular shape. For example, the film-forming support substrate 100F shown in FIG. 6 is provided intermittently along the outer shape of the four square-shaped film-forming target portions 130F and the film-forming target portion 130F, and the thickness of the film-forming support substrate 100F. A slit 140F penetrating in the longitudinal direction and a connecting portion 150F located between the slits 140F are provided. At this time, similarly to the above-described embodiment, the size of the film-forming target portion 130F is preferably about 1 mm to 3 mm larger than the size of the desired silicon carbide polycrystalline substrate. When the film-forming target portion has a shape other than a circular shape, a cutting machine equipped with a flat plate-shaped rotary blade or the like is used as a separation tool after the silicon carbide polycrystalline film 200 is formed. Can be done.

Further, the number of the film forming target portions 130 is not limited to four, and may be one to three or five or more.

Further, the film-forming support substrate may be further provided with a holding hole for holding the film-forming support substrate in the central portion of the film-forming support substrate on the film-forming target surface. The film-forming support substrate 100G shown in FIG. 7 is provided with a holding hole 160G in the central portion of the film-forming target surface 110 into which a holding rod or the like for holding the film-forming support substrate 100G can be inserted.

Such a film-forming support substrate 100G can be held, for example, by inserting a holding rod having a diameter similar to that of the holding hole 160G into the holding hole 160G and fixing it from both sides with nuts or the like. .. In the case of a film-forming support substrate not provided with a holding hole 160G, it was necessary to hold the film-forming support substrate so that it would not fall even during fixing work with a nut or the like, but a holding hole is provided. As a result, the fixing operation can be performed without holding the film-forming support substrate. Therefore, it is possible to improve workability when holding the film-forming support substrate 100G in a film-forming apparatus or the like.

Further, in the film forming step, the film forming support substrate 100G can be rotated around the holding hole 160G, whereby the silicon carbide polycrystalline film 200 can be formed more uniformly.

Further, although the film-forming support substrate 100 of the present embodiment has two film-forming target surfaces (film-forming target surfaces 110 and 120), the film-forming target may be one surface and is a silicon carbide polycrystal. It may be appropriately determined depending on the conditions such as the production plan of the substrate and the structure of the vapor deposition furnace. Further, even when the silicon carbide polycrystalline substrate 500 is manufactured using the film-forming support substrate 100 of the present embodiment, the silicon carbide polycrystalline film may be formed on only one side.

[Manufacturing method of silicon carbide polycrystalline substrate]
Next, a method for manufacturing the polycrystalline substrate of the present embodiment using the film-forming support substrate 100 of FIG. 1 will be described. In the present embodiment, as described above, a method for producing a silicon carbide polycrystalline substrate will be illustrated and described. The method for manufacturing the silicon carbide polycrystalline substrate of the present embodiment includes a film forming step of forming the silicon carbide polycrystalline film 200 on the film-forming target surfaces 110 and 120 of the film-forming support substrate 100 by a chemical vapor deposition method. , The inside of the slit 140 is separated from the laminate 300 of the support substrate 100 for film formation and the silicon carbide polycrystalline film 200 on which the silicon carbide polycrystalline film 200 is formed, and the silicon carbide polycrystalline film 200 is separated. It includes a separation step of obtaining a substrate intermediate 400 and a removal step of removing the support substrate 100 for film formation from the silicon carbide polycrystalline substrate intermediate 400 to obtain a silicon carbide polycrystalline substrate 500.

Next, the method for producing the silicon carbide polycrystalline substrate of the present embodiment will be described in the order of the film forming step, the separating step, and the removing step.

(Film formation process)
The film forming process will be described with reference to FIGS. 1 to 4. The following description is an example of the film forming process, and each condition such as temperature, pressure, gas atmosphere, and the procedure may be changed within a range where there is no problem.

Here, FIG. 3 shows the line AA of FIG. 1 showing the support substrate for film formation, the silicon carbide polycrystalline film, and the silicon carbide polycrystalline substrate in each step of the method for manufacturing the silicon carbide polycrystalline substrate of the present embodiment. It is sectional drawing which shows typically. That is, FIG. 3 is a view showing a cross section of a portion where the slit 140 is not formed. Further, the line E in FIGS. 1 and 3 shows the boundary between the film forming target portion 130 and the connecting portion 150. Further, FIG. 4 is a cross-sectional view of a laminated body of a support substrate for film formation after forming a silicon carbide polycrystalline film and a silicon carbide polycrystalline film in the cross section of FIG. 1 BB. That is, FIG. 4 is a cross-sectional view of the laminated body at the portion where the slit is formed.

In the film forming step, after the film forming support substrate 100 shown in FIGS. 1 and 3 (A) is prepared, the film forming target surfaces 110 and 120 of the film forming support substrate 100 are subjected to a chemical vapor deposition method. This is a step of forming a film of the silicon carbide polycrystalline film 200, and can be performed by using, for example, the film forming apparatus 1000 described below.

As shown in FIG. 2, the film forming apparatus 1000 includes a housing 1010 that is an exterior of the film forming apparatus 1000 and a film forming chamber 1020 that forms a film-forming silicon carbide polycrystalline film 200 on the film-forming support substrate 100. The exhaust gas introduction chamber 1050 that introduces the raw material gas and the carrier gas discharged from the film chamber 1020 into the gas discharge port 1040 described later, the box 1060 that covers the exhaust gas introduction chamber 1050, and the inside of the film formation chamber 1020 from the outside of the box 1060. A carbon heater 1070 that heats the film, a gas inlet 1030 that is provided above the film forming chamber 1020 and introduces a raw material gas or a carrier gas into the film forming chamber 1020, a gas discharge port 1040, and a film forming chamber. It has a substrate holder 1080 that holds the support substrate 100. Further, the substrate holder 1080 has a rod-shaped holding member 1081 and a holding pedestal 1082 for fixing the holding member 1081 in the film forming chamber 1020. Further, the holding pedestal 1082 is provided at two places inside the side wall of the film forming chamber 1020, and the holding pedestal 1082 is formed with holes (not shown) into which the holding member 1081 can be inserted and fixed. , The longitudinal direction of the rod-shaped holding member 1081 can be held horizontally. Further, in the holding member 1081, the portion where the film-forming support substrate 100 is held is threaded for fastening the nut N1 and the nut N2, which will be described later. That is, as shown in FIG. 4, in the film forming apparatus 1000, the film forming support substrate 100 is sandwiched and fixed by the nuts N1 and N2, so that the film forming target surfaces 110 and 120 are attached to the holding member 1081. Is held so that it is in the vertical direction. In the present embodiment, the film-forming support substrate 100 is held so that the film-forming target surfaces 110 and 120 are in the vertical direction, but the holding method is not particularly limited. For example, the film-forming target surface 110 , 120 may be held in the horizontal direction. The number of film-forming support substrates 100 held in the film-forming chamber 1020 is not particularly limited, and may be one or a plurality. Further, in order to deposit the silicon carbide polycrystalline film 200 more uniformly on the film forming target surfaces 110 and 120 of the film forming support substrate 100, the film forming support substrate 100 is rotated in the film forming step. May be good.

The specific procedure of the film forming process will be described. First, the film-forming support substrate 100 is held in the film-forming chamber 1020, under reduced pressure, under an inert gas atmosphere such as Ar, and up to the film-forming reaction temperature by the heater 1070. To heat. When the reaction temperature of the film formation is reached, the supply of the inert gas is stopped, and the raw material gas or the carrier gas containing the component of the silicon carbide polycrystalline film 200 is supplied into the film formation chamber 1020.

The film formation temperature of the silicon carbide polycrystalline film can be about 1000 ° C. to 1400 ° C.

The raw material gas is not particularly limited as long as the silicon carbide polycrystalline film 200 can be formed, and Si-based raw material gas and C-based raw material gas generally used for forming the silicon carbide polycrystalline film are used. be able to. For example, as the Si-based raw material gas, silane (SiH ₄ ) can be used, monochlorosilane (SiH ₃ Cl), dichlorosilane (SiH ₂ Cl ₂ ), trichlorosilane (SiHCl ₃ ), tetrachlorosilane (SiCl _4). ) And other chlorine-based Si raw material-containing gas (chloride-based raw material) containing Cl having an etching action can be used. As the C-based raw material gas, for example, _{hydrocarbons such as methane (CH 4} ), propane (C ₃ H ₈ ), and acetylene (C ₂ H ₂ ) can be used. In addition to the above, trichloromethylsilane (CH ₃ Cl ₃ Si), trichlorophenylsilane (C ₆ H ₅ Cl ₃ Si), dichloromethylsilane (CH ₄ Cl ₂ Si), dichlorodimethylsilane ((CH ₃ ) ₂ SiCl ₂₎ ), A method of reducing and thermally decomposing an organic silicon compound such as chlorotrimethylsilane ((CH ₃ ) _{3 SiCl) in the gas phase can also be used.}

Further, as the carrier gas, a commonly used carrier gas can be used as long as the raw material gas can be developed on the film forming support substrate 100 without inhibiting the film formation of the silicon carbide polycrystalline film 200. can. _{For example, an H 2} gas having excellent thermal conductivity and having an etching action on silicon carbide can be used as a carrier gas. Further, at the same time as these raw material gas and carrier gas, an impurity doping gas can be simultaneously supplied as a third gas. For example, when the conductive type of the silicon carbide polycrystalline substrate obtained by separating the silicon carbide polycrystalline film 200 from the film-forming support substrate 100 is n-type, it is nitrogen (N ₂ ), and when it is p-type. Can use trimethylaluminum (TMA).

When forming the silicon carbide polycrystalline film 200, the above gas is appropriately mixed and supplied. Further, conditions such as a gas mixing ratio and a supply amount may be changed during the film forming process according to the desired properties of the silicon carbide polycrystalline film 200.

Further, when forming a film other than silicon carbide, the film forming conditions such as gas, temperature, pressure, and time can be set according to the polycrystal to be formed. When forming a polycrystalline film of titanium nitride, TiCl ₄ gas, N ₂ gas and the like can be used. When forming a polycrystalline film of aluminum nitride, AlCl ₃ gas, NH ₃ gas and the like can be used. When forming a polycrystalline film of titanium carbide, TiCl ₄ gas, CH ₄ gas and the like can be used. When forming a diamond-like carbon polycrystalline film, a hydrocarbon gas such as acetylene can be used.

The silicon carbide polycrystalline film 200 can be formed on both surfaces of the heated film-forming support substrate 100 by a chemical reaction on the surface of the film-forming support substrate 100 or in the gas phase. As a result, as shown in FIGS. 3 (B) and 4, the silicon carbide polycrystalline film 200 is formed on the film-forming support substrate 100, and the film-forming support substrate 100 and the silicon carbide polycrystalline film 200 are formed. The laminate 300 is obtained.

Here, as shown in FIG. 3B, a flat plate-shaped silicon carbide polycrystalline film 200 is formed along the film-forming target surfaces 110 and 120 of the film-forming support substrate 100 at a location where the slit 140 is not formed. A film is formed. On the other hand, as shown in FIG. 4, a silicon carbide polycrystalline film 200 having a shape along the slit 140 is formed at a portion where the slit 140 is formed.

The film-forming thickness of the silicon carbide polycrystalline film 200 in the film-forming step is preferably set to such a thickness that the slit 140 is not filled in consideration of workability in the separation step described later. That is, the silicon carbide polycrystal film is considered to be processed such as the desired thickness of the silicon carbide polycrystal substrate and the thickness and flatness processing of the silicon carbide polycrystal substrate after separating the support substrate 100 for film formation. The film thickness of 200 can be determined, and the width dimension of the slit 140 can be determined based on the film thickness. The film thickness can be, for example, about 0.5 mm to 1.5 mm.

The laminate 300 formed as described above is cooled to about room temperature and then subjected to a separation step.

(Separation process)
The separation step is a step of separating the inside of the slit 140 at the slit 140 (line C in FIG. 5B) from the laminate 300 to obtain the silicon carbide polycrystalline substrate intermediate 400. It should be noted that the silicon carbide polycrystalline film 200 formed on the film-forming target portion 130 is outside the boundary (line E in FIGS. 1 and 3) between the film-forming target portion 130 and the connecting portion 150 so as not to damage the film-forming silicon carbide polycrystalline film 200 (FIG. It is preferable to separate at the line C) of 3 (B).

Specifically, in the present embodiment, since the slit 140 is formed in a circular shape, for example, a tool for cutting linearly or a core drill for cutting in a circular shape (FIGS. 3B and 4). The inside of the slit 140 can be separated by cutting the portion of the line C with a tool such as M). When a core drill is used, since the inside of the slit 140 is used in a later process, it is possible to perform processing using only a drill (core bit) that cuts into a circular shape without using a center drill. By using a core drill, workability can be improved when a circular silicon carbide polycrystalline substrate intermediate 400 is obtained. When the slit of the film-forming support substrate is not formed in a circular shape, the inside of the slit may be separated by cutting according to the shape of the slit using a cutting machine provided with a rotary blade or the like.

By the above separation step, the silicon carbide polycrystalline substrate intermediate 400 shown in FIG. 3C is obtained.

(Removal process)
The removing step is a step of removing the film-forming target portion 130 of the film-forming support substrate 100 from the silicon carbide polycrystalline substrate intermediate 400 to obtain the silicon carbide polycrystalline substrate 500. The film-forming target portion 130 can be removed by heating to several hundred degrees in an atmosphere of an oxidizing gas such as _{O 2 or air and burning only the film-forming target portion 130.} Since the silicon carbide polycrystalline substrate intermediate 400 is obtained by separating the laminate 300 at the slit 140, the side surface of the film formation target portion 130 is exposed as shown in FIG. 3C. If necessary, the silicon carbide polycrystalline substrate intermediate 400 may be subjected to a slicing process in which the film formation target portion 130 is sliced at the portion line D in FIG. 3C. By performing the slicing process on the silicon carbide polycrystalline substrate intermediate 400, the exposed area of the film-forming target portion 130 becomes large, and the film-forming target portion 130 can be burnt and removed more efficiently.

Further, after the removal step, diameter / chamfering, thickness / flatness processing, and cleaning are performed as necessary. Diameter / chamfering is the process of grinding the outer peripheral portion with a diamond grindstone or the like to the desired diameter dimension to remove the excess portion and adjust the diameter to the desired diameter dimension. The processing is performed to reduce the corners of the entire outer peripheral portion. In addition, in order to obtain a thickness and flatness suitable for applications such as manufacturing a substrate bonded to a silicon carbide single crystal substrate, the film-forming surface is ground and polished to obtain the thickness and flatness. It is something to adjust. From the above, a silicon carbide polycrystalline substrate (FIG. 3 (D)) can be obtained.

The method for manufacturing the silicon carbide polycrystalline substrate of the present embodiment includes a film forming step of forming the silicon carbide polycrystalline film 200 on the film-forming target surfaces 110 and 120 of the film-forming support substrate 100 by a chemical vapor deposition method. , The inside of the slit 140 is separated from the laminate 300 of the support substrate 100 for film formation and the silicon carbide polycrystalline film 200 on which the silicon carbide polycrystalline film 200 is formed, and the silicon carbide polycrystalline film 200 is separated. It includes a separation step of obtaining a substrate intermediate 400 and a removal step of removing the support substrate 100 for film formation from the silicon carbide polycrystalline substrate intermediate 400 to obtain a silicon carbide polycrystalline substrate 500.

According to the method for manufacturing a silicon carbide polycrystal substrate of the present embodiment, the silicon carbide polycrystal film 200 is formed on the film-forming support substrate 100 of the present embodiment, and the inside of the slit 140 is formed at the slit 140. By separating the film, the film target portion is formed from the laminate 300 of the film-forming support substrate 100 and the film-formed silicon carbide polycrystalline film 200, as compared with the film-forming support substrate on which the slit 140 is not formed. It is easy to separate the laminate (silicon carbide polycrystal substrate intermediate 400) from the filmed film. Therefore, the time required for separation is shortened, the production efficiency is improved, the wear of the separation tool is suppressed, and the cost can be reduced by extending the life of the separation tool.

In addition, the best configuration, method, and the like for carrying out the present invention are disclosed in the above description, but the present invention is not limited thereto. That is, although the present invention has been particularly described mainly with respect to a specific embodiment, the shape, material, quantity, and the shape, material, quantity, and the like, without departing from the scope of the technical idea and purpose of the present invention, are as opposed to the above-described embodiments. In other detailed configurations, those skilled in the art can make various modifications. Therefore, the description that limits the shape, material, etc. disclosed above is merely an example for facilitating the understanding of the present invention, and does not limit the present invention. Therefore, those shapes, materials, etc. The description by the name of the member which removes a part or all of the limitation such as is included in the present invention.

Hereinafter, the present invention will be described 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 this embodiment, the film-forming support substrate 100 of the above-described embodiment is held by the holding member 1081, and the film-forming step of forming the silicon carbide polycrystalline film 200 by using the film-forming device 1000 is performed. The separation step was performed using a core drill.

(Example 1)
As the film-forming support substrate, four film-forming target portions having a circular shape and a diameter dimension of 151 mm were set on a graphite support substrate having a diameter of 360 mm and a thickness of 6 mm. Further, for each film-forming target portion, a circular slit having an inner diameter dimension of 151 mm and a width dimension of 2 mm, which penetrates in the thickness direction, is formed so as not to overlap the film-forming target surface. Further, the slit is divided into four by four connecting portions, and the length dimension of each connecting portion is 1 mm. In addition, the surface to be filmed was both sides of the film-forming support substrate.

Ten such support substrates for film formation were held in the film formation chamber of the film formation apparatus 1000 of the above-described embodiment so that the surface to be filmed was in the vertical direction, and the film formation step was performed. First, the inside of the film forming chamber 1020 was evacuated by an exhaust pump (not shown), and then heated to 1320 ° C. _{SiCl 4} and CH ₄ were used as the raw material gas, _{H 2} was used as the carrier _{gas, and N 2} was used as the impurity doping gas. The silicon carbide polycrystalline film is formed _{by mixing the above gases at a ratio of SiC 4} : CH ₄ : H ₂ : N ₂ = 1: 1:10: 10 and supplying them into the film forming chamber 1020 for 20 hours. A film was formed. At this time, the film thickness was 0.8 mm to 1.2 mm.

Next, a separation step was performed. Regarding the laminate of the film-forming support substrate and the silicon carbide polycrystalline film, the inside of the slit was separated at the slit to obtain a silicon carbide polycrystalline substrate intermediate. For the separation step, a core drill having an inner diameter of 151 mm and an outer diameter of 152 mm and having 170 count diamond abrasive grains was used. In the separation step, it was necessary to separate the silicon carbide polycrystalline substrate intermediate at 40 film formation target portions formed on the 10 film-forming support substrates to separate the silicon carbide polycrystalline substrate intermediate. The time was measured and the average time of 40 times was calculated. Further, the silicon carbide polycrystalline substrate intermediate was separated from the 40 film-forming target portions formed on the 10 film-forming support substrates, and the grindstone wear rate of the core drill was confirmed. The grindstone wear rate was calculated as the wear size of the core drill (mm) / the processing thickness of the laminate (mm) × 100 (%). Table 1 shows the results of the width dimension of the slit, the length dimension of the connecting portion, the separation time of the silicon carbide polycrystalline substrate intermediate, and the grindstone wear rate. Further, the obtained silicon carbide polycrystalline substrate intermediate was sliced on the film-forming support substrate, and then subjected to a removal step to remove the film-forming support substrate. The silicon carbide polycrystalline substrate after the film-forming support substrate was removed was subjected to diameter / chamfering, thickness / flatness processing, and cleaning to obtain a silicon carbide polycrystalline substrate. It was confirmed by visual confirmation that the obtained silicon carbide polycrystalline substrate had no problems such as damage.

It was judged that the efficiency of the separation step was good when the separation time was less than 5 minutes, and the efficiency of the separation step was poor when the separation time was 5 minutes or more. Further, when the grindstone wear rate is less than 10%, it is judged that the processing cost is low due to the extension of the tool life. When the grindstone wear rate was 10% or more, it was judged that the tool life was short and the machining cost was high.

(Examples 2 to 4, Comparative Examples 1 to 3)
A silicon carbide polycrystalline substrate was produced in the same manner as in Example 1 except that the width dimension of the slit formed in the film-forming support substrate and the length dimension of the connecting portion were variously changed. In Comparative Example 1, no slit was formed. The width dimension of the slit was 3 mm in Example 2, 2 mm in Example 3, 1 mm in Comparative Example 2, and 2 mm in Comparative Example 3. The length of the connecting portion was 1 mm in Example 2, 10 mm in Example 3, 0.5 mm in Comparative Example 2, and 20 mm in Comparative Example 3. Table 1 shows the time required to separate the silicon carbide polycrystalline substrate intermediate and the grindstone wear rate. In Comparative Example 2, the slit was filled after the silicon carbide polycrystalline film was formed. The silicon carbide polycrystalline substrate after the film-forming support substrate was removed was subjected to diameter / chamfering, thickness / flatness processing, and cleaning to obtain a silicon carbide polycrystalline substrate. It was confirmed by visual confirmation that the obtained silicon carbide polycrystalline substrate had no problems such as damage.

In Examples 1 to 3 which are exemplary embodiments of the present invention, the separation time is less than 5 minutes and the grindstone wear rate is less than 10%. Therefore, the separation process is efficient and low cost. rice field. In addition, the separation time and the grindstone wear rate were significantly reduced as compared with Comparative Example 1 in which no slit was formed.

In Comparative Example 1 and Comparative Example 2, the separation time was 5 minutes or more and the grindstone wear rate was 10% or more, both of which were inefficient in the separation process and high in cost. Further, in Comparative Example 3, although the separation time and the grindstone wear rate were reduced as compared with Comparative Examples 1 and 2, the separation time was longer than that in the example due to the long length of the connecting portion, and the efficiency of the separation process was increased. The conversion was not enough. Further, in Comparative Example 2 in which the width of the slit is narrow, the slit is filled by forming the silicon carbide polycrystalline film, and the separation time is shorter than that in Comparative Example 1 in the separation step, but the effect of reducing the separation time is achieved. Was almost nonexistent.

From the above, in the method for producing the film-forming support substrate and the silicon carbide polycrystalline substrate according to the examples of the present invention, the film-forming support substrate in which no slit is formed is compared with the film-forming support substrate. After film formation, it is easy to separate the laminate of the film formation target part and the film film, the time required for separation is shortened, the production efficiency is improved, and the wear of the separation tool is suppressed for separation. Costs can be reduced by extending the life of the tool.

100 Support substrate for film formation 110, 120 Surface to be filmed 130 Target to be filmed 140 Slit 150, 150B, 150C, 150D, 150E, 150F Connection part 151, 152, 153 Groove 200 Silicon carbide polycrystalline film 300 Laminated body 400 Carbide Silicon Polycrystalline Substrate Intermediate 500 Silicon Carbide Polycrystalline Substrate M Core Drill

Claims (10)

It has a surface to be deposited by the chemical vapor deposition method.
The surface to be filmed is
The film formation target part separated after film formation and the film formation target part
A slit that is intermittently provided along the outer shape of the film-forming target portion and penetrates in the thickness direction of the film-forming support substrate, and
It has a connecting portion located between the slits and
A support substrate for film formation having a length dimension of the connection portion of 1 mm to 10 mm. The support substrate for film formation according to claim 1, wherein two or more of the connecting portions are provided. The film-forming support substrate according to claim 1 or 2, wherein the width dimension of the slit is 2 mm to 10 mm. The film-forming support substrate is a support substrate for obtaining a circular substrate by separating the film-forming target portion after film formation.
The film formation target portion has a circular shape in a plan view.
The support substrate for film formation according to any one of claims 1 to 3, wherein the diameter dimension of the film forming target portion is 1 mm to 3 mm larger than the diameter dimension of the circular substrate. The film-forming support substrate according to any one of claims 1 to 4, wherein the film-forming target portions are formed at a plurality of locations so as not to overlap each other on the film-forming target surface. The film-forming support substrate according to any one of claims 1 to 5, wherein the connecting portion is provided with a groove formed in the thickness direction. The film-forming support substrate according to claim 6, wherein the groove has a rectangular cross section. The support substrate for film formation according to any one of claims 1 to 7, which has a plurality of through holes formed in a perforation shape along the length direction at the connection portion. A method for producing a polycrystalline substrate using the film-forming support substrate according to any one of claims 1 to 8.
A polycrystalline film is formed on the film-forming target surface of the film-forming support substrate by a chemical vapor deposition method, and the laminate of the film-forming support substrate and the polycrystalline film is formed at the slit portion. , A separation step of separating the inside of the slit to obtain a polycrystalline substrate intermediate.
A method for manufacturing a polycrystalline substrate, comprising a removing step of removing the film-forming support substrate from the polycrystalline substrate intermediate to obtain a polycrystalline substrate. The film formation target portion has a circular shape in a plan view.
The method for manufacturing a polycrystalline substrate according to claim 9, wherein in the separation step, the slit is cut using a core drill to separate the inside of the slit.

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