JP7206871B2 - METHOD FOR MANUFACTURING POLYCRYSTALLINE SILICON CARBIDE SUBSTRATE AND PLATE-TYPE SUBSTRATE - Google Patents

Description

The present invention relates to a polycrystalline silicon carbide substrate to which single-crystal silicon carbide is bonded and used, for example, for a silicon carbide semiconductor. It is about the method.

Silicon carbide (SiC) is a compound semiconductor material composed of silicon (Si) and carbon. Since it is possible to control the required p-type and n-type in a wide range, it is expected as a material for power devices that exceeds the limits of silicon. Furthermore, since silicon carbide can provide a high withstand voltage even with a small film thickness, it is possible to obtain a semiconductor with low ON resistance and low loss by reducing the film thickness of silicon carbide.

However, it is difficult to manufacture a large-area single-crystal silicon carbide substrate (wafer) from a silicon carbide semiconductor compared to the widely used Si semiconductor, and the manufacturing process is also complicated. Mass production of single-crystal silicon carbide substrates has been difficult and expensive.

Therefore, various measures have been taken to reduce the cost of silicon carbide semiconductors. For example, Patent Document 1 discloses a method of manufacturing a silicon carbide substrate by bonding a single crystal silicon carbide substrate and a polycrystalline silicon carbide substrate together. That is, at least, a single crystal silicon carbide substrate having a micropipe density of 30 micropipes/cm ² or less and a polycrystalline silicon carbide substrate are bonded together, and then the single crystal silicon carbide substrate is thinned to form a silicon carbide semiconductor. A method for manufacturing a provided silicon carbide substrate is described. Incidentally, the single crystal silicon carbide substrate functions as the device active layer of the silicon carbide semiconductor, and the polycrystalline silicon carbide substrate plays the role of the lower mechanical support portion and the heat radiation portion. can be handled in the same way as a substrate made of silicon carbide.

Furthermore, in Patent Document 1, a hydrogen ion-implanted layer is formed on a single-crystal silicon carbide substrate before bonding a single-crystal silicon carbide substrate and a polycrystalline silicon carbide substrate together, and single-crystal silicon carbide with the hydrogen-ion-implanted layer is formed. After bonding the substrate and the polycrystalline silicon carbide substrate together, a heat treatment is performed at a temperature of 350° C. or less to thin the single crystal silicon carbide substrate with the hydrogen ion-implanted layer as a peeling surface of the single crystal silicon carbide substrate. A method is also described.

Further, by the method described in Patent Document 1, more silicon carbide substrates to be used for silicon carbide semiconductors can be obtained from one large-area single-crystal silicon carbide ingot.

JP 2009-117533 A

By the way, a polycrystalline silicon carbide substrate, in which single crystal silicon carbide is bonded together and used for a silicon carbide semiconductor or the like, is generally manufactured by a vapor deposition method such as a thermal CVD method.

That is, the growth furnace in which the flat film-forming substrate (base material substrate) is arranged is set to an environment of 1300 ° C. or higher, and Si-based raw material gas such as SiH ₄ and C-based raw material such as CH ₄ are placed in the furnace. A gas, a nitrogen gas as an impurity gas, and a hydrogen gas as a carrier gas are introduced, and polycrystalline silicon carbide is deposited on the front and back surfaces and the outer peripheral end face of the flat film-forming substrate by thermal reaction.

Then, the flat plate-shaped substrate on which polycrystalline silicon carbide is deposited is taken out from the growth furnace, and the flat plate-shaped substrate is beveled to expose the end face of the flat film-formation substrate, Only the flat film-forming substrate (made of a high-purity carbon material, etc., as described later) is burned (disappeared by firing) using an electric furnace or the like, and formed on the front and back surfaces of the flat film-forming substrate. Two polycrystalline silicon carbide substrates made of polycrystalline silicon carbide films are obtained.

However, in the above-described method for manufacturing a polycrystalline silicon carbide substrate, when the flat plate-shaped film formation substrate is burned, only the thickness of the side surface of the flat film formation substrate (base material substrate) is exposed. It is difficult for heat to be transmitted to the entire substrate, and it takes time to burn (disappear by firing), which is a bottleneck in the processing process.

In addition, since the polycrystalline silicon carbide substrate is used by laminating single crystal silicon carbide, which is a semiconductor, the polycrystalline silicon carbide substrate is required to be free from metal contamination. For this reason, a high-purity carbon material that does not cause metal contamination and can withstand high-temperature environments is used as the material of the flat plate-shaped substrate (base material substrate) on which polycrystalline silicon carbide is deposited (film-formed). It is

However, although carbon materials can withstand high temperatures, they have low mechanical strength and are difficult to impart spring properties. The base material substrate 1 is fixed by sandwiching it with a jig (consisting of a rod 2, a spacer 3 for sandwiching the base material substrate 1, a nut 4 for fixing the spacer 3, etc.) made of a carbon nut or the like, or A method of placing and fixing it on a nail-shaped mounting portion or the like is adopted. In this state, when polycrystalline silicon carbide is deposited (film-formed) on the front and back surfaces and the outer peripheral end face of the flat substrate to be film-formed (base material substrate) 1, as shown in FIG. Polycrystalline silicon carbide 5 is also deposited (film-formed) on the jig and mounting portion (not shown), and the deposited (film-formed) polycrystalline silicon carbide 5 forms a bond between the jig or mounting portion and the flat film-forming substrate. (Base material substrate) 1 will stick.

When the jig or the like is fixed to the flat film-forming substrate (base material substrate) 1, when the base material substrate 1 is cooled from the high-temperature environment after the deposition (film-forming) of polycrystalline silicon carbide is completed, the polycrystalline Cracks or the like may occur in the polycrystalline silicon carbide film or base material substrate 1 due to stress generated between a jig or the like and the polycrystalline silicon carbide film due to shrinkage of the silicon carbide film.

In addition, even in the case of the planar film-forming substrate (base material substrate) 1 in which cracks or the like of the polycrystalline silicon carbide film do not occur, when removing the portion fixed to the jig etc. Therefore, the polycrystalline silicon carbide film at the fixed portion is damaged (substrate missing portion 6 is shown in FIG. 4), so that the polycrystalline silicon carbide film is formed. There is a problem that the circular shape of the base material substrate 1 on which the film is formed cannot be maintained.

The present invention has been made by paying attention to such a problem, and the object thereof is to shorten the disappearance time in the planar film-forming substrate (base material substrate), which has been a bottleneck in the manufacturing process. In addition, damage to the polycrystalline silicon carbide film, the flat plate-shaped substrate (base material substrate), etc. can be suppressed, and the circular shape of the base material substrate on which the polycrystalline silicon carbide film is formed can be maintained. It is an object of the present invention to provide a method for manufacturing a polycrystalline silicon carbide substrate that can achieve this, and also to provide a flat plate-like substrate for film formation that is applied to this manufacturing method.

Therefore, the present inventors have conducted intensive research into a method for shortening the dissipation time in the flat substrate for film formation (base material substrate) and preventing damage to the polycrystalline silicon carbide film, the flat substrate for film formation, and the like. As a result of stacking, the flat plate-shaped substrate for film formation is configured by the upper flat substrate and the lower flat substrate which are detachably integrated, and after exposing the end surface of the flat plate-shaped substrate for film formation, The present inventors have found that this can be achieved by separating the upper flat substrate and the lower flat substrate and removing (disappearing) both substrates. Furthermore, by adopting a structure in which an insertion hole is formed in the outer peripheral end face of the lower flat substrate and an insertion jig for fixing and holding the lower flat substrate is fitted into the insertion hole of the lower flat substrate, It has also been found that the circular shape of a flat substrate on which a polycrystalline silicon carbide film is formed can be maintained.

That is, the first invention according to the present invention is
a film formation step of forming a polycrystalline silicon carbide film on the front and back surfaces and the outer peripheral end face of the flat plate-shaped substrate fixed by the holding means by a vapor deposition method;
an end face exposing step of removing the polycrystalline silicon carbide film formed on the outer peripheral end face of the flat plate-shaped film formation substrate separated from the holding means to expose the outer peripheral end face of the flat film formation substrate;
a removing step of removing the flat plate-shaped film formation substrate with the outer peripheral end face exposed to obtain two polycrystalline silicon carbide substrates composed of polycrystalline silicon carbide films formed on the front and back surfaces of the flat film-formation substrate;
In a method for manufacturing a polycrystalline silicon carbide substrate comprising
The flat plate-like substrate to be filmed is composed of an upper flat plate-like substrate and a lower flat plate-like substrate separably integrated,
Further, the holding means to which the flat plate-like substrate is fixed is an insertion hole formed in the outer peripheral end face of the lower flat-plate-like substrate, and an insertion hole which is inserted into the insertion hole to fix and hold the lower flat-plate-like substrate. Along with configuring with a jig ,
After the end face exposing step, the upper flat substrate and the lower flat substrate are separated and removed.

Moreover, the second invention according to the present invention is
In the method for manufacturing a polycrystalline silicon carbide substrate according to the first invention,
After separating the upper flat substrate and the lower flat substrate, both substrates are removed by a combustion method to obtain two polycrystalline silicon carbide substrates,
The third invention is
In the method for manufacturing a polycrystalline silicon carbide substrate according to the first invention,
After separating the upper flat substrate and the lower flat substrate, both substrates are removed by surface grinding to obtain two polycrystalline silicon carbide substrates.

Moreover, the fourth invention is
In a flat plate-shaped substrate for film formation used in the method for manufacturing a polycrystalline silicon carbide substrate according to any one of the first to third inventions,
It is composed of an upper flat substrate having a convex fitting portion and a lower flat substrate having a concave fitting portion into which the fitting portion is fitted. It is characterized by having a shaped insertion hole.

According to the method for manufacturing a polycrystalline silicon carbide substrate according to the present invention,
A flat plate-shaped substrate on which a polycrystalline silicon carbide film is formed on the front and back surfaces is composed of an upper flat substrate and a lower flat substrate that are detachably integrated, and the flat plate-shaped substrate on which a film is formed is provided. After exposing the end faces of the upper and lower flat substrates, the upper and lower flat substrates are separated, and both substrates are removed (disappeared) while the mating surfaces of the upper and lower flat substrates are exposed. In addition, it is possible to shorten the removal (disappearance) time of the plate-like film formation substrate, and prevent damage to the polycrystalline silicon carbide film, the plate-like film formation substrate, and the like.

In addition, the holding means for fixing the flat plate-like substrate is composed of an insertion hole formed in the outer peripheral end surface of the lower flat plate-like substrate, and an insertion hole which is inserted into the insertion hole to fix and hold the lower flat plate-like substrate. Since it is configured with a jig, it is possible to maintain the circular shape of the planar substrate on which the polycrystalline silicon carbide film is formed.

Holding means (rods 2, spacers 3 for sandwiching the base material substrate 1, nuts 4 for fixing the spacers 3, etc.) hold the flat plate-shaped substrate (base material substrate) 1 on which the polycrystalline silicon carbide film is to be formed in the growth furnace. Schematic perspective view showing a state fixed by a jig). FIG. 2 is a side view of FIG. 1; When the flat substrate to be film-formed (base material substrate) is fixed by the holding means shown in FIG. ) is fixed. When the flat plate-shaped film formation substrate (base material substrate) is removed from the holding means when the flat film formation substrate (base material substrate) is fixed to the holding means by the deposited (deposited) polycrystalline silicon carbide film 1 is a schematic perspective view showing a substrate cutout portion 6 formed in FIG. FIG. 5(A) is a schematic perspective view before the upper flat substrate and the lower flat substrate constituting the flat film formation substrate (base material substrate) are integrated, and FIG. 5(B) is the lower flat plate. holding means for a flat substrate to be film-formed (base material substrate) comprising an insertion hole formed in the outer peripheral end surface of the flat substrate and an insertion jig inserted into the insertion hole to fix the lower flat substrate. Explanatory diagram showing. FIG. 6A shows that a polycrystalline silicon carbide film is deposited (film-formed) on the front and back surfaces and the outer peripheral end face of a flat film-forming substrate (base material substrate) composed of an upper flat substrate and a lower flat substrate. An explanatory view showing the state in which the base material substrate is separated from the rod, and FIG. FIG. 6C is an explanatory diagram showing a state in which the jig (holding plate) is removed, and FIG. 6C is an explanatory diagram showing a state in which the upper flat substrate and the lower flat substrate are separated and their mating surfaces are exposed.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail.

A method for manufacturing a polycrystalline silicon carbide substrate according to the present invention includes an upper flat substrate that is detachably integrated with a flat film-formed substrate (base material substrate) on which polycrystalline silicon carbide is formed on front and back surfaces. and a lower flat substrate.

(1) Holding Means According to a Reference Example in which a Part of a Base Material Substrate is Sandwiched by Spacers , as shown in FIGS. 1 and 2, it is composed of a rod 2 with triangular threads, a spacer 3 for sandwiching the base material substrate 1, and a hexagonal nut 4 for fixing the spacer 3. Each material is are all made of carbon material. By arranging the spacers 3 and the hexagonal nuts 4 on a single rod 2 at regular intervals, it is possible to simultaneously perform film formation on a plurality of flat film-forming substrates (base substrates) 1 . Become.

By the way, in the case of adopting a holding means in which a part of the base material substrate is sandwiched by spacers, as described above, in addition to the front and back surfaces and the outer peripheral end surface of the flat film-forming substrate (base material substrate) 1, as shown in FIG. As shown, the polycrystalline silicon carbide 5 is also deposited (film-formed) on the outer peripheral surfaces of the rod 2, the spacer 3, and the nut 4 that constitute the holding means. The (base material substrate) 1 and the holding means are fixed.

Therefore, when the flat film-forming substrate (base material substrate) 1 on which the polycrystalline silicon carbide 5 is formed is removed from the holding means, the flat film-forming substrate (base material substrate) sandwiched by the spacers 3 of the holding means ) 1 must be removed. 4 is formed, the circular shape of the flat film-forming substrate (base material substrate) 1 cannot be maintained.

However, since the flat film-forming substrate (base material substrate) is composed of the upper flat substrate and the lower flat substrate which are separably integrated, the upper flat substrate is formed after the end face exposing step. It is possible to separate the substrate and the lower flat substrate and remove (disappear) the upper and lower flat substrates while exposing the mating surfaces of the upper and lower flat substrates. There is an advantage that the removal (disappearance) time in the substrate can be shortened, and the breakage of the polycrystalline silicon carbide film, flat substrate, etc., can be reduced as the removal (disappearance) time is shortened. Furthermore, since both substrates can be removed (disappeared) while the mating surfaces of the upper and lower flat substrates are exposed, in addition to the conventional combustion method (disappearance method by firing using an electric furnace), Grinding makes it possible to remove the upper flat substrate and the lower flat substrate.

(2) Holding means according to the present invention comprising an insertion hole in the lower flat substrate and an insertion jig fixed to the rod
The flat film-forming substrate (base material substrate) held by the holding means according to the present invention includes, as shown in FIG. An insertion hole 10 having a rectangular cross section is provided in the outer peripheral end surface of the lower flat substrate 8, and the bottom flat substrate 8 has a recessed fitting portion 80 in which the 70 is fitted. As shown in FIG. 5B, upper flat substrate 7 and lower flat substrate 8 are integrated and used for manufacturing a polycrystalline silicon carbide substrate.

An insertion jig (holding plate) 9 fixed to the rod 2 shown in FIG. A holding plate 9 serves to hold an integrated flat film-forming substrate (base material substrate) 1 . 5(B), reference numeral 4 denotes a hexagonal nut for fixing the insertion jig (holding plate) 9 to the rod 2. As shown in FIG.

When such a holding means is adopted, in addition to the front and back surfaces and the outer peripheral end face of the flat plate-shaped film-forming substrate (base substrate) 1, each of the rod 2, the nut 4, and the insertion jig (holding plate) 9 is held. Polycrystalline silicon carbide 5 is also formed on the outer peripheral surface, but as shown in FIG. ), the flat film-forming substrate (base material substrate) 1 on which the polycrystalline silicon carbide 5 is formed can be removed from the rod 2, so that the flat plate-shaped substrate shown in FIG. After the end face exposing step of exposing the end face of the film formation target substrate (base material substrate) 1, the circular shape of the flat film formation target substrate (base material substrate) 1 can be maintained.

After the end face exposing step, the upper flat substrate 7 and the lower flat substrate 8 are separated as shown in FIG. Since both substrates can be removed (disappeared) in an exposed state, the removal (disappearance) time of the flat substrate for film formation can be shortened, and the removal (disappearance) time is shortened. Damage to the polycrystalline silicon carbide film, the flat substrate for film formation, etc. can be reduced, and the circular shape of the flat substrate for film formation (base material substrate) 1 can be maintained (that is, no substrate chipped portion 6 is formed). This has the advantage that the polycrystalline silicon carbide film formed on the planar film-forming substrate (base material substrate) 1 can be utilized without waste. Furthermore, since the upper flat substrate 7 and the lower flat substrate 8 can be removed (disappeared) in a state where the mating surfaces of the upper flat substrate 7 and the lower flat substrate 8 are exposed, in addition to the conventional burning method (disappearance method by firing using an electric furnace), It is possible to remove the upper flat substrate 7 and the lower flat substrate 8 by surface grinding.

(3) Examples of Insertion Hole and Insertion Jig (Holding Plate) Regarding the insertion hole 10 formed in the outer peripheral end surface of the lower flat substrate 8 shown in FIG. It is desirable that the insertion hole 10 has a depth of 30 mm or more and a rectangular cross-sectional shape in order to maintain the perpendicularity of the base material substrate 1 with respect to the rod 2 .

On the other hand, an insertion jig (holding plate) 9 fixed to the rod 2 has an outer dimension smaller than that of the insertion hole 10 by 0.1 mm to 0.2 mm. A plate-like film-forming substrate (base material substrate) 1 integrated by being fitted into an insertion hole 10 of 8 is held.

In FIG. 5A, one insertion hole 10 is provided in the outer peripheral end face of the lower flat plate-like substrate 8, but the insertion hole 10 is formed so as to stably hold the flat plate-like substrate (base material substrate) 1. A plurality of insertion holes 10 may be provided. However, it is necessary to provide insertion jigs (holding plates) 9 corresponding to the set number of insertion holes 10 (and a plurality of rods 2 as well).

Unlike the above holding means in which a part of the base material substrate is sandwiched by spacers, the holding means using an insertion hole and an insertion jig (holding plate) has an insertion jig ( By cutting the base end side of the holding plate 9, the base material substrate 1 having the polycrystalline silicon carbide 5 formed thereon can be removed from the rod 2, so that the base material substrate is shown in FIG. It becomes possible to maintain the circular shape of the base material substrate 1 after the end surface exposing step of exposing the end surface of the base material substrate 1, and as a result, the circular polycrystalline silicon carbide film formed on the base material substrate 1 is effectively used. It becomes possible to

EXAMPLES Hereinafter, examples of the present invention will be specifically described with reference to comparative examples, but the configuration of the present invention is not limited to the following examples.

[Example 1]
A circular upper flat substrate 7 having a convex circular fitting portion 70 shown in FIG. 5A and a circular lower flat substrate 8 having a concave circular fitting portion 80 into which the fitting portion 70 is fitted A circular base material substrate 1 made of carbon was produced.

The diameter of the circular base material substrate 1 is 4 inches, the thickness of the central portion of the circular upper flat substrate 7 (that is, the upper flat substrate including the convex circular insertion portion 70) is 2 mm, and the circular upper flat substrate 7 has a thickness of 1 mm (that is, the upper flat substrate excluding the circular fitting portion 70), and the central portion of the circular lower flat substrate 8 (that is, the concave circular fitting portion 80) is 1 mm thick. ) is 5 mm in thickness, the peripheral portion of the circular lower flat plate-like substrate 8 (that is, the lower flat plate-like substrate excluding the circular fitting portion 80) has a thickness of 7 mm, and the upper flat plate-like substrate 7 and the The total substrate thickness when the lower flat substrate 8 was integrated was set to 8 mm.

The hole size of the insertion hole 10 provided in the outer peripheral end face of the circular lower flat plate-shaped substrate 8 and having a rectangular cross section is 15.0 mm in horizontal dimension, 1.5 mm in vertical dimension, and 35 mm in depth. The size of the insertion jig (holding plate) 9 which is fitted into the insertion hole 10 and has a rectangular cross section is 14.8 mm in width, 1.3 mm in length, and 30.0 mm in length. A through hole for fixing the rod 2 is provided on the base end side of the jig (holding plate) 9 .

That is, a rod 2 (L25 mm×M6: "M6" is a bolt standard) threaded with a triangular screw is vertically passed through the through-hole of the insertion jig (retaining plate) 9, as shown in FIG. 5(B). , an insertion jig (retaining plate) 9 is fixed with a hexagonal nut 4 . Each insertion jig (holding plate) 9 is fixed to the rod 2 at equal intervals of 10 mm, and each insertion jig (holding plate) 9 is fitted into the insertion hole 10 of the circular lower flat plate-like substrate 8 to form an upper circular plate. A circular base substrate 1 made of carbon and composed of a flat substrate 7 and a circular lower flat substrate 8 was fixed and held.

The insertion depth of the insertion jig (holding plate) 9 into the insertion hole 10 of each circular lower flat plate substrate 8 is set to 20 mm, and ten sets of circular base material substrates (circular upper flat substrates) are attached to the rod 2. 7 and a circular lower flat plate-like substrate 8 were integrated, and a polycrystalline silicon carbide film formation test was conducted by fixing a circular base material substrate 1) by thermal CVD.

As a result of the film formation test, the two sets of insertion jigs (holding plates) 9 arranged at the bottom were damaged and fell off, so the two sets of circular base material substrates held by these insertion jigs (holding plates) 9 were removed. The four polycrystalline silicon carbide substrates on which the film was formed on 1 became defective, and the other two sets of circular base material substrates 1 contacted and adhered during the film formation, and the two sets of circular base material substrates 1 became defective. The four polycrystalline silicon carbide substrates on which films were formed were also defective. As for the remaining six sets of circular base material substrates 1, each insertion jig (holding plate) 9 can be cut to remove the six sets of circular base material substrates 1 without damaging the polycrystalline silicon carbide substrates. rice field.

Then, the removed six sets of circular base material substrates 1 are subjected to end surface processing, and after separating the integrated upper circular flat substrate 7 and the circular lower flat substrate 8, electric power is applied at a set temperature of 800°C. It was confirmed that the circular upper flat substrate 7 and the circular lower flat substrate 8 were baked in a furnace, and that each base material substrate disappeared after 12 hours.

Table 1 shows the results.

[Example 2]
From the results of Example 1, the insertion with respect to the weight of the circular base material substrate (consisting of integrated circular upper flat plate substrate 7 and circular lower flat substrate 8) having polycrystalline silicon carbide films formed on the front and back surfaces. It was found that the strength (rigidity) of the jig (holding plate) 9 was insufficient. The size of the fixture (holding plate) 9 was changed as follows.

That is, the insertion hole 10 has a horizontal dimension of 15.0 mm, a vertical dimension of 3.0 mm (the vertical dimension of the insertion hole in Example 1 is 1.5 mm), and a depth of 35 mm. The size of the insertion jig (retaining plate) 9 to be inserted into the hole 10 is 14.8 mm in the horizontal dimension, 2.8 mm in the vertical dimension (the vertical dimension of the retaining plate in Example 1 is 1.3 mm), and the length dimension. is 40.0 mm, the insertion depth of the insertion jig (holding plate) 9 into the insertion hole 10 of each circular lower flat substrate 8 is 30 mm, and ten sets of circular base material substrates (circular A circular base material substrate 1 formed by integrating an upper flat substrate 7 and a circular lower flat substrate 8 was fixed, and a film formation test of polycrystalline silicon carbide by thermal CVD was performed in the same manner as in Example 1. .

As a result of the film formation test, no drop-off or contact was confirmed for any of the circular base material substrates (circular base material substrates formed by integrating the circular upper flat plate-like substrate 7 and the circular lower flat plate-like substrate 8) 1 . Also, for all circular base material substrates 1, each insertion jig (holding plate) 9 was cut, and all circular base material substrates 1 could be removed without damaging the polycrystalline silicon carbide substrates.

Then, all the removed circular base material substrates 1 were subjected to end surface processing, and after separating the integrated circular upper flat plate-like substrate 7 and circular lower flat plate-like substrate 8, an electric furnace with a set temperature of 800° C. was placed. It was confirmed that the circular upper flat substrate 7 and the circular lower flat substrate 8 were fired by the above method, and that each base material substrate disappeared in 12 hours.

Table 1 shows the results.

[Comparative Example 1]
Thermal CVD by applying a conventional circular carbon base material substrate (single plate-shaped film-forming substrate that is not divided into two in the thickness direction) and adopting a holding means that sandwiches a part of the base material substrate with a spacer. A film formation test of polycrystalline silicon carbide was conducted.

As in Examples 1 and 2, carbon was used as the material for all parts, and the size of the circular base material substrate was 4 inches and the thickness was 1.0 mm.

As for the holding means shown in FIG. 1, which sandwiches a part of the base material substrate between spacers, the same rod 2 (L25 mm×M6) as in the embodiment in which the triangular screw is processed, and the spacer 3 (lengthwise and widthwise sizes are 20.0 mm × 15.0 mm, thickness 3.0 mm), and the same hexagonal nut 4 as in the embodiment for fixing the spacer 3, and ten circular base material substrates 1 are attached to the rod 2 at regular intervals of 10 mm. was fixed, and a film formation test of polycrystalline silicon carbide by thermal CVD was conducted.

As a result of the film formation test, in Comparative Example 1, since a holding means was adopted in which a part of the base material substrate was sandwiched between spacers, all the circular base material substrates 1 had the substrate defect portion 6 shown in FIG. In addition, one of the ten circular base material substrates 1 was cracked, and two polycrystalline silicon carbide substrates formed on the circular base material substrate 1 became defective.

Then, the nine circular base material substrates 1 removed are subjected to end surface processing, and the circular base material substrates 1 are fired in an electric furnace at a set temperature of 800° C., and each base material substrate disappears in 110 hours. I was able to confirm that.

Table 1 shows the results.

[Verification]
(1) In Examples 1 and 2, the circular base material substrate 1 composed of the upper flat substrate 7 and the lower flat substrate 8 that are separated in the thickness direction and integrated is applied. After exposing the end surface of the circular base material substrate 1 by end surface processing, the upper flat substrate 7 and the lower flat substrate 8 are separated, and the mating surfaces of the upper flat substrate 7 and the lower flat substrate 8 are formed. Since both substrates (that is, the upper flat substrate 7 and the lower flat substrate 8) are removed (disappeared) in an electric furnace while the is exposed, the removal (disappearance) time for the circular base material substrate 1 is shortened (comparative example The firing time of Example 1 is 110 hours, while the firing time of Examples 1 and 2 is 12 hours).

(2) In Comparative Example 1, since the holding means (see FIG. 1) in which a portion of the circular base material substrate 1 is sandwiched by the spacers 4 is employed, the circular base material substrate 1 after film formation is inevitably Since the substrate defect portion 6 (see FIG. 4) is formed in the substrate (substrate defect rate is 100%), it is confirmed that the polycrystalline silicon carbide film cannot be effectively utilized.

(3) On the other hand, in Examples 1 and 2, since the holding means comprising the insertion hole 10 of the lower flat substrate 8 and the insertion jig (holding plate) 9 fixed to the rod 2 is adopted, It is confirmed that there is an advantage that the polycrystalline silicon carbide films formed on the front and back surfaces of the circular base material substrate 1 can be effectively utilized because the substrate defect portion 6 is not formed (substrate defect rate is 0%).

According to the method for manufacturing a polycrystalline silicon carbide substrate according to the present invention, the manufacturing time can be shortened and the manufacturing can be simplified. It has industrial applicability as a manufacturing method.

1 flat film-forming substrate (base material substrate)
2 Rod 3 Spacer 4 Hexagonal Nut 5 Polycrystalline Silicon Carbide 6 Substrate Missing Portion 7 Upper Flat Substrate 8 Lower Flat Substrate 9 Insertion Jig (Holding Plate)
10 insertion hole 70 convex fitting portion 80 concave fitting portion

Claims (4)

a film formation step of forming a polycrystalline silicon carbide film on the front and back surfaces and the outer peripheral end face of the flat plate-shaped substrate fixed by the holding means by a vapor deposition method;
an end face exposing step of removing the polycrystalline silicon carbide film formed on the outer peripheral end face of the flat plate-shaped film formation substrate separated from the holding means to expose the outer peripheral end face of the flat film formation substrate;
a removing step of removing the flat plate-shaped film formation substrate with the outer peripheral end face exposed to obtain two polycrystalline silicon carbide substrates composed of polycrystalline silicon carbide films formed on the front and back surfaces of the flat film-formation substrate;
In a method for manufacturing a polycrystalline silicon carbide substrate comprising
The flat plate-like substrate to be filmed is composed of an upper flat plate-like substrate and a lower flat plate-like substrate separably integrated,
Further, the holding means to which the flat plate-like substrate is fixed is an insertion hole formed in the outer peripheral end face of the lower flat-plate-like substrate, and an insertion hole which is inserted into the insertion hole to fix and hold the lower flat-plate-like substrate. Along with configuring with a jig ,
A method of manufacturing a polycrystalline silicon carbide substrate, wherein the upper flat substrate and the lower flat substrate are separated and removed after the end face exposing step. 2. The polycrystalline silicon carbide substrate according to claim 1, wherein after the upper flat substrate and the lower flat substrate are separated, both substrates are removed by a combustion method to obtain two polycrystalline silicon carbide substrates. Substrate manufacturing method. 2. The polycrystalline silicon carbide substrate according to claim 1, wherein after the upper flat substrate and the lower flat substrate are separated, both substrates are removed by surface grinding to obtain two polycrystalline silicon carbide substrates. Substrate manufacturing method. A flat film-formed substrate used in the method for manufacturing a polycrystalline silicon carbide substrate according to any one of claims 1 to 3 ,
It is composed of an upper flat substrate having a convex fitting portion and a lower flat substrate having a concave fitting portion into which the fitting portion is fitted. 1. A flat substrate for film formation, comprising a shaped insertion hole.

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