JP6232680B2 - How to clean the susceptor - Google Patents

Description

  The present invention relates to a method for cleaning a susceptor used in a film forming chamber of a silicon carbide film forming apparatus.

A film forming apparatus such as a CVD apparatus or an epitaxial apparatus is an apparatus for growing a thin film on the surface of a predetermined substrate. In such a film forming apparatus, when a thin film is formed, a solid material containing a thin film precursor as a component is deposited on a susceptor on which the substrate is placed. Hereinafter, this solid substance is referred to as a deposit.
As described above, when a deposit is formed on the susceptor, the deposit is peeled off to cause particles, thereby deteriorating the quality of the thin film formed on the surface of the substrate.

  Patent Document 1 discloses an ex-situ dry cleaning in which a member constituting a film forming apparatus to which deposits are attached is taken out and the deposits attached to the members are removed by a dry cleaning apparatus. Has been.

  Specifically, in Patent Document 1, silicon contained in silicon carbide is supplied by supplying a plasma-containing fluorine-containing gas into a processing chamber that houses a member of a silicon carbide film forming apparatus to which silicon carbide is adhered. A first step of removing a component, and a second step of removing a carbon component contained in silicon carbide by supplying a plasma-ized oxygen-containing gas into the processing chamber, A method for removing silicon carbide in which the step and the second step are performed alternately or simultaneously is disclosed.

  By using the method for removing silicon carbide disclosed in Patent Document 1, it is possible to accurately remove the carbon component and silicon component contained in silicon carbide that is the main component of the deposit. In other words, it is possible to accurately remove deposits attached to the members of the silicon carbide film forming apparatus.

JP 2012-182373 A

As described above, by using the method for removing silicon carbide disclosed in Patent Document 1, deposits deposited on the members of the silicon carbide film forming apparatus can be accurately removed.
However, in Patent Document 1, the problem described later occurs.

  FIG. 14 is a diagram showing a part of a conventional susceptor. FIG. 14A is a perspective view of a conventional susceptor (a cross-sectional view of only the outer peripheral portion of the susceptor), and FIG. 14B is a cross-sectional view of the susceptor in the XX direction shown in FIG. is there.

FIG. 15 is a diagram for explaining the problems of the conventional deposit removal method. FIG. 15A is a cross-sectional view of a susceptor housed in a film forming chamber of a silicon carbide film forming apparatus and on which a silicon carbide substrate is placed. FIG. 15B is a cross-sectional view of a susceptor on which a silicon carbide substrate having a silicon carbide film formed on the surface is placed and deposited in a film forming chamber of a silicon carbide film forming apparatus. It is.
FIG. 15C is a cross-sectional view of the susceptor taken out of the film formation chamber of the silicon carbide film formation apparatus and deposits deposited after removing the silicon carbide substrate on which the silicon carbide film is formed. FIG. 15D is a cross-sectional view of the susceptor housed in the chamber of the silicon carbide removing apparatus and on which the susceptor protection substrate is placed. FIG. 15E is a cross-sectional view of the susceptor from which deposits have been removed by the silicon carbide removing device.

Next, with reference to FIG. 14 and FIGS. 15A to 15E, the conventional silicon carbide (deposit) removal method will be described while the conventional deposit removal method is described. The problem of will be described.
First, a susceptor 300 shown in FIG. 14 is prepared. Here, a configuration of the susceptor 300 will be described with reference to FIGS. 14 and 15A to 15E.
The susceptor 300 includes a susceptor main body 301 and a housing portion 302 disposed on the surface of the susceptor main body 301. The susceptor body 301 has a disk shape, and a member 300-1 made of carbon is coated with a coating 300-2 made of a silicon carbide film.
The thickness of the silicon carbide film to be the coating 300-2 is very thin, for example, 200 μm.

The accommodating part 302 has the 1st recessed part 302A arrange | positioned at the surface side of the susceptor main body 301, and the 2nd recessed part 302B.
First recess 302A is a disk-shaped space, and supports silicon carbide substrate 305 by contacting a surface located on the outer peripheral portion of the back surface of silicon carbide substrate 305.

The inner diameter of first recess 302A is larger than the outer diameter of silicon carbide substrate 305 shown in FIG. 15A and the outer diameter of susceptor protection substrate 311 shown in FIG.
Thereby, gap Y is formed between the outer peripheral edge of silicon carbide substrate 305 and the side wall of first recess 302A.
Further, as shown in FIG. 15D, when the cleaning process of the susceptor 300 is performed, the susceptor protection substrate 311 is placed in the first recess 302A.

  The second recess 302B is disposed immediately below the first recess 302A, and is integrated with the first recess 302A. The second recess 302B has a disk shape. The inner diameter of second recess 302B is configured to be smaller than the outer diameter of silicon carbide substrate 305 and the outer diameter of susceptor protection substrate 311 shown in FIG.

  Next, in the step shown in FIG. 15A, the silicon carbide substrate 305 is placed in the first recess 302A of the susceptor 300 housed in a film forming chamber (not shown) of a silicon carbide film forming apparatus (not shown). Is placed. At this stage, a gap Y (for example, 1 to 2 mm) is formed between the outer peripheral edge of silicon carbide substrate 305 and the side wall of first recess 302A.

Next, in the step shown in FIG. 15B, a silicon carbide film 307 is formed on the surface 305a of the silicon carbide substrate 305 by a known method. At this time, the deposit 308 containing silicon carbide as a main component is deposited on the upper surface of the susceptor 300 in which the housing portion 302 is not formed and the bottom surface of the first recess 302A located in the gap Y.
Here, the deposit 308 is a deposit (a deposit made of silicon carbide) that is deposited by repeatedly performing the film forming process of the silicon carbide film, and is not thin, for example, about 20 to 50 μm. Having a thickness of
At this stage, since the deposit 308 is not deposited on the side surface of the first recess 302A, the side surface of the first recess 302A is exposed from the deposit 308.

  Next, in the step shown in FIG. 15C, after the silicon carbide substrate 305 on which the silicon carbide film 307 shown in FIG. 15B is formed is recovered, the film formation chamber (not shown) of the silicon carbide film formation apparatus (not shown). The susceptor 300 on which the deposit 308 is deposited is taken out outside (not shown).

Next, in the step shown in FIG. 15D, the susceptor 300 with the deposit 308 attached is housed in a chamber (not shown) of a silicon carbide removing device (not shown). Next, the susceptor protection substrate 311 is placed in the first recess 302 </ b> A of the housing portion 302 of the susceptor 300.
As susceptor protection substrate 311, a substrate having the same shape as silicon carbide substrate 305 (in other words, the same thickness and the same outer diameter) is used.

Next, in the step shown in FIG. 15E, the deposit 308 deposited on the susceptor 300 shown in FIG. 15D is removed by the method (dry etching) disclosed in Patent Document 1.
At this time, the plasma-containing fluorine-containing gas (gas for removing the silicon component contained in the deposit 308) and the plasma-ized oxygen-containing gas (gas for removing the carbon component contained in the deposit 308) ) The directionality is not controlled.
Therefore, the plasma travels not only in the vertical direction from the upper side of the film forming chamber toward the upper surface of the susceptor 300 but also in various directions such as an oblique direction and a lateral direction.

  For this reason, the coating 302 located on the side wall of the first recess 302A where the deposit 308 is not deposited is etched by the plasma entering the gap Y and traveling in various directions, so that the carbon member 300-1 is formed. It will be exposed (see region Z shown in FIG. 15E).

  As described above, when the silicon carbide film is formed on the surface of the silicon carbide substrate using the susceptor 300 with the carbon exposed, the problem that the silicon carbide film is contaminated by the carbon and the film quality of the silicon carbide film are deteriorated. (In other words, the susceptor 300 from which the deposit 308 has been removed cannot be used again).

  SUMMARY OF THE INVENTION An object of the present invention is to provide a susceptor cleaning method that can suppress contamination of a silicon carbide film caused by carbon and that can reuse a susceptor from which deposits have been removed.

In order to solve the above-described problem, according to the first aspect of the present invention, susceptor cleaning is performed to remove deposits made of silicon carbide deposited on a susceptor including a housing portion that houses a silicon carbide substrate on which a silicon carbide film is formed. A method of preparing a silicon carbide susceptor composed only of bulk silicon carbide as the susceptor, and a step of taking out the silicon carbide susceptor to which the deposit is attached from a film forming chamber of a silicon carbide film forming apparatus. A step of accommodating the silicon carbide susceptor to which the deposit is attached in a chamber of a silicon carbide removing device, and disposing a susceptor protection substrate for protecting the silicon carbide susceptor in the accommodating portion; and A first step of selectively removing a silicon component contained in the deposit by supplying a plasma-containing fluorine-containing gas; And a second step of selectively removing a carbon component contained in the deposit by supplying a plasma-containing oxygen-containing gas into the chamber, the first step and the second step see contains a etching step for alternately or simultaneously bets, the surface of the susceptor protective substrate, such that the flush with the top surface of the susceptor, characterized by disposing the susceptor protective substrate to the housing part A susceptor cleaning method is provided.

Further, the invention according to claim 2, after the etching step, the steps of the susceptor to RCA cleaning, after the RCA cleaning, a step of washing the susceptor with ultrapure water, washed with the ultrapure water And a step of drying the susceptor. The method of cleaning a susceptor according to claim 1 is provided.

According to the invention of claim 3, the susceptor cleaning method according to claim 1 or 2, wherein an average surface roughness Ra of the silicon carbide susceptor from which the deposit is removed is 1 μm or less. Is provided.

According to the susceptor cleaning method of the present invention, by using a silicon carbide susceptor composed only of bulk silicon carbide, even if the silicon carbide susceptor is etched in the etching process, carbon is used as the material of the silicon carbide susceptor. This prevents carbon from being exposed. Thereby, it can suppress that the silicon carbide film formed in a silicon carbide substrate is contaminated with carbon.
Further, by using a silicon carbide susceptor composed only of bulk silicon carbide, the silicon carbide susceptor can be cleaned using a liquid.

Bulk silicon carbide has a surface roughness value smaller than that of a silicon carbide film as a film, and thus is difficult to be etched in the etching process. For this reason, in the process (etching process) in the first and second steps, it is possible to reduce the amount of etching (etching amount) of the silicon carbide susceptor.
Therefore, the silicon carbide susceptor from which the deposit has been removed can be used again to form a silicon carbide film having a good film quality.

  Furthermore, by cleaning the silicon carbide susceptor from which deposits have been removed in the first and second steps by RCA cleaning, components (for example, F component) contained in the etching gas (plasma-containing fluorine-containing gas and oxygen-containing gas) And N component) can be removed, so that contamination of the silicon carbide film due to the etching gas can be suppressed.

  The susceptor cleaning method is particularly effective when removing thick deposits deposited on a silicon carbide susceptor by dry cleaning using an ex-situ method (Ex-Situ).

It is a top view of the silicon carbide susceptor used with the cleaning method of the susceptor which concerns on embodiment of this invention. It is the figure which expanded the part enclosed by the area | region A among the silicon carbide susceptors shown in FIG. 1, (a) is a perspective view of the part enclosed by the area | region A (only the outer peripheral part of a silicon carbide susceptor is sectional drawing). FIG. 6B is a sectional view of the silicon carbide susceptor shown in FIG. It is sectional drawing to which the silicon carbide susceptor in which the silicon carbide substrate was mounted was expanded. It is sectional drawing which shows typically the schematic structure of the batch type silicon carbide film-forming apparatus which can use the silicon carbide susceptor shown in FIGS. It is a figure which shows the other silicon carbide susceptor which can apply the cleaning method of the susceptor of this Embodiment, (a) is a perspective view of a silicon carbide susceptor, (b) is the silicon carbide shown to (a) It is sectional drawing of the FF line direction of a susceptor. It is sectional drawing which shows typically schematic structure of the batch type silicon carbide film-forming apparatus which can use the silicon carbide susceptor shown to Fig.5 (a), (b). It is a figure which shows schematic structure of the silicon carbide removal apparatus used when performing the cleaning method of the susceptor which concerns on this Embodiment. It is sectional drawing of the chamber for demonstrating the structure in the chamber shown in FIG. It is a figure which shows the flowchart for demonstrating the cleaning method of the susceptor which concerns on this Embodiment. It is a figure for demonstrating each process which comprises the cleaning method of the susceptor which concerns on this Embodiment. (A) is sectional drawing of the principal part of the prepared silicon carbide susceptor. (B) is a cross-sectional view of a silicon carbide susceptor arranged in a film forming chamber of a silicon carbide film forming apparatus and having a silicon carbide substrate placed on a housing portion of the silicon carbide susceptor. (C) is a cross-sectional view of a silicon carbide susceptor and a silicon carbide substrate in which a deposit made of silicon carbide is deposited after forming a silicon carbide film on the surface of the silicon carbide substrate. (D) is a cross-sectional view of a silicon carbide susceptor in which a silicon carbide substrate on which a silicon carbide film is formed is collected, taken out from a film formation chamber of a silicon carbide film formation apparatus, and deposits are deposited. (E) is sectional drawing of the silicon carbide susceptor and the susceptor protection board which were accommodated in the chamber of the silicon carbide removal apparatus, the susceptor protection board was arrange | positioned in the accommodating part, and the deposit accumulated. (F) is a cross-sectional view of the silicon carbide susceptor after deposits are removed. It is a top view which shows schematic structure of the susceptor used by the comparative example. It is sectional drawing of the GG line direction of the susceptor shown in FIG. It is a graph which shows the relationship between the average surface roughness Ra (micrometer) and the etching rate (micrometer / min) of porous silicon carbide, a silicon carbide coat (presence / absence of polishing), and bulk silicon carbide (presence / absence of polishing). It is a figure which shows a part of conventional susceptor. (A) is a perspective view of a conventional susceptor (a sectional view of only the outer peripheral portion of the susceptor), and (b) is a sectional view of the susceptor shown in (a) in the XX line direction. It is a figure for demonstrating the problem of the removal method of the conventional deposit. (A) is sectional drawing of the susceptor in which it accommodated in the film-forming chamber of the silicon carbide film-forming apparatus, and the silicon carbide substrate was mounted. (B) is sectional drawing of the susceptor which the silicon carbide board | substrate with which the silicon carbide film | membrane in which the silicon carbide film | membrane was formed in the film-forming chamber of a silicon carbide film-forming apparatus was mounted is mounted, and the deposit deposited. . (C) is a cross-sectional view of the susceptor taken out of the film forming chamber of the silicon carbide film forming apparatus and deposits deposited after removing the silicon carbide substrate on which the silicon carbide film is formed. (D) is sectional drawing of the susceptor accommodated in the chamber of the silicon carbide removal apparatus, and the susceptor protection board | substrate was mounted. (E) is sectional drawing of the susceptor from which the deposit was removed by the silicon carbide removal apparatus.

  Embodiments to which the present invention is applied will be described below in detail with reference to the drawings. The drawings used in the following description are for explaining the configuration of the embodiment of the present invention. The size, thickness, dimensions, and the like of each part shown in the drawings are the actual susceptor, silicon carbide film forming device, and The dimensional relationship of the silicon carbide removing device may be different.

(Embodiment)
FIG. 1 is a plan view of a silicon carbide susceptor used in a susceptor cleaning method according to an embodiment of the present invention. C shown in FIG. 1 indicates the center of the susceptor body 11 (hereinafter referred to as “center C”).
2 is an enlarged view of a portion surrounded by region A in the silicon carbide susceptor shown in FIG. 1, and (a) is a perspective view of the portion surrounded by region A (only the outer peripheral portion of the silicon carbide susceptor). (B) is a sectional view in the DD line direction of the silicon carbide susceptor shown in (a).
FIG. 3 is an enlarged cross-sectional view of a silicon carbide susceptor on which a silicon carbide substrate is placed. 3 indicates the surface direction of the silicon carbide substrate 20 (in other words, the surface direction of the silicon carbide substrate 20) (hereinafter referred to as “surface direction S”). 3 shows silicon carbide film 21 formed on surface 20a of silicon carbide substrate 20 for convenience of explanation.
In FIG. 1, FIG. 2 (a), (b), and FIG. 3, the same code | symbol is attached | subjected to the same component.

First, silicon carbide susceptor 10 used in the susceptor cleaning method of the present embodiment will be described with reference to FIGS. 1, 2A, 2B, and 3. FIG.
Silicon carbide susceptor 10 is a susceptor used in a deposition chamber of a batch-type silicon carbide film forming apparatus for simultaneously forming a silicon carbide film on a plurality of silicon carbide substrates. Storage section 12 (eight in the case of FIG. 1).

The susceptor body 11 is a disk-shaped member, and its outer shape is circular. The susceptor body 11 has an upper surface 11a and a lower surface 11b that are flat surfaces. The susceptor body 11 is composed only of bulk silicon carbide (specifically, for example, 3C—SiC). In other words, silicon carbide susceptor 10 is composed only of bulk silicon carbide.
For this reason, the average surface roughness of the surface of the susceptor body 11 (specifically, the surface including the upper surface 11a, the lower surface 11b, and the side surface of the susceptor body 11 and the surface of the susceptor body 11 constituting the housing portion 12). Ra can be, for example, 1 μm or less.

Generally, the surface of bulk silicon carbide is very smooth compared to the surface of a silicon carbide coat film formed using a silicon carbide coat film forming apparatus (for example, the average surface roughness Ra is 10 μm). It is considered as a surface. Therefore, when bulk silicon carbide and a silicon carbide film are etched using anisotropic dry etching, the rougher surface is more easily etched, so the bulk silicon carbide having a smooth surface is etched. The speed at which the silicon carbide coat film is etched is about 1/10 of the speed at which the silicon carbide coat film is etched.
That is, by using bulk silicon carbide as the material of silicon carbide susceptor 10, etching can be made more difficult than silicon carbide coat film.

Here, a method of smoothing the surface of bulk silicon carbide will be described. As a method of smoothing the surface of bulk silicon carbide, for example, mirror polishing can be used.
By using the mirror polishing, the average surface roughness Ra of the surface of the bulk silicon carbide can be set to about 0.02 μm.

  The standard average surface roughness Ra of the bulk silicon carbide before the mirror polishing process is about 2 μm, but the bulk silicon carbide can be subjected to the mirror polishing process. For this reason, as described above, the average surface roughness Ra of the surface of the bulk silicon carbide after the mirror polishing process can be set to about 0.02 μm.

  On the other hand, the silicon carbide coat film formed so as to cover the surface of the member made of carbon is firmly adhered to the carbon, but when the mirror polishing is performed, the silicon carbide coat film is broken (specifically, In this case, the silicon carbide coat film is peeled off or cracked), so that mirror polishing cannot be performed.

  It is possible to polish the surface of the silicon carbide coat film using sandpaper instead of mirror polishing, but when the average surface roughness Ra of the silicon carbide coat film after film formation is 10 μm, Even if the silicon carbide coat film is polished after the film formation, it is best to improve the average surface roughness Ra to about 1 μm.

  By setting the average surface roughness Ra of the silicon carbide susceptor 10 to 0.5 μm or less, for example, the rate at which bulk silicon carbide is etched is set to about 1/30 of the rate at which the silicon carbide film is etched. Can do.

  A plurality (eight in the case of FIG. 1) of the accommodating portions 12 are provided on the upper surface 11 a side of the susceptor body 11. The plurality of accommodating portions 12 are arranged at equal intervals on the circumference B centering on the center C of the susceptor body 11 so that the plurality of accommodating portions 12 are located. The accommodating part 12 has the 1st recessed part 12-1 and the 2nd recessed part 12-2.

The first recess 12-1 is provided on the upper surface 11 a side of the susceptor body 11 so that the upper end thereof is exposed from the upper surface 11 a of the susceptor body 11. The first recess 12-1 is disposed above the second recess 12-2 and is integrated with the second recess 12-2. The shape of the first recess 12-1 is a disk shape.
The first recess 12-1 is a portion in which the silicon carbide substrate 20 on which the silicon carbide film 21 (for example, 4H—SiC film) is formed on the surface 20a is accommodated.

  1st recessed part 12-1 is the ring-shaped bottom face 12- which contacts the surface arrange | positioned in the outer peripheral part among the back surfaces 20b of the silicon carbide substrate 20 in the part located in the outer side of 2nd recessed part 12-2. 1a. Silicon carbide substrate 20 is supported by the outer peripheral portion of back surface 20b coming into contact with bottom surface 12-1a of first recess 12-1.

The opening diameter of first recess 12-1 is slightly larger than the outer diameter (caliber) of silicon carbide substrate 20. Thereby, the first recess 12-1 is formed in a state where a ring-shaped gap E is formed between the inner wall of the first recess 12-1 and the outer peripheral edge 20A of the silicon carbide substrate 20. Support. The magnitude | size of the clearance gap E can be 1-2 mm, for example.
When the outer diameter of silicon carbide substrate 20 is 4 inches (102 mm), the opening diameter of first recess 12-1 can be set to 104 mm, for example.

For example, the depth of the first recess 12-1 when the upper surface 11a of the susceptor body 11 is used as a reference may be the same as the thickness of the silicon carbide substrate 20.
That is, the surface 20 a of the silicon carbide substrate 20 accommodated in the accommodating portion 12 is preferably flush with the upper surface 11 a of the susceptor body 11.

  Thus, by making the surface 20a of the silicon carbide substrate 20 accommodated in the first recess 12-1 (accommodating portion 12) flush with the flat upper surface 11a of the susceptor body 11, the raw material is laterally viewed. When a vapor phase growth apparatus (silicon carbide film forming apparatus) that supplies gas is used, it is possible to suppress the flow of the raw material gas from colliding with the convex portion, and thus the plurality of silicon carbide substrates 20 can be controlled. A good silicon carbide film can be formed on the surface 20a.

  First recess 12-1 configured as described above supports silicon carbide substrate 20 and regulates the position of silicon carbide substrate 20 in surface direction S.

  The 2nd recessed part 12-2 is provided in the susceptor main body 11 located under the 1st recessed part 12-1. The shape of the 2nd recessed part 12-2 is made into the disk shape whose opening diameter is smaller than the 1st recessed part 12-1. The second recess 12-2 is integrated with the upper end of the first recess 12-1. Second recess 12-2 exposes most of back surface 20b of silicon carbide substrate 20 placed on bottom surface 12-1a of first recess 12-1.

  Thus, while providing the 2nd recessed part 12-2 which exposes most of the back surface 20b of the silicon carbide substrate 20 under the 1st recessed part 12-1, it is set as the ring shape of the 1st recessed part 12-1. By supporting the outer peripheral portion of the back surface 20b of the silicon carbide substrate 20 by the bottom surface 12-1a, even if the silicon carbide substrate 20 is warped by heating, the entire silicon carbide substrate 20 is caused by the radiant heat from the susceptor body 11. It can be heated uniformly.

Moreover, the ring of the 1st recessed part 12-1 is comprised compared with the case where there is no 2nd recessed part 12-2 by comprising the accommodating part 12 by the 1st and 2nd recessed parts 12-1 and 12-2. The contact area between shaped bottom surface 12-1a and back surface 20b of silicon carbide substrate 20 is considerably reduced.
For this reason, it can suppress that back surface 20b of silicon carbide substrate 20 is contaminated by impurities (for example, heavy metal) contained in silicon carbide constituting silicon carbide susceptor 10.

  FIG. 4 is a cross-sectional view schematically showing a schematic configuration of a batch-type silicon carbide film forming apparatus that can use the silicon carbide susceptor shown in FIGS. 1, 2 (a), 2 (b), and 3. 4, the same components as those shown in FIGS. 1, 2A, 2B, and 3 are denoted by the same reference numerals.

  Referring to FIG. 4, a batch type silicon carbide film forming apparatus 30 includes a film forming chamber 31, a stage 33, a first heating unit 35, a first heat insulating member 37, an exhaust port 38, and a rotation. A shaft 39, a rotation drive unit 41, a susceptor receiving member 42, a ceiling plate member 43, a second heating unit 44, a second heat insulating member 45, a third heat insulating member 47, and a raw material gas outlet unit 49.

The film forming chamber 31 accommodates the stage 33, the silicon carbide susceptor 10 on which the plurality of silicon carbide substrates 20 are placed, and the end of the source gas outlet 49. Film forming chamber 31 has reaction space 31 </ b> A between silicon carbide susceptor 10 and ceiling plate member 43. The stage 33 is disposed at the bottom of the film forming chamber 31.
The first heating unit 35 is installed below the stage 33. The first heating unit 35 sets the plurality of silicon carbide substrates 20 to a predetermined temperature by radiant heat and heat conduction of the silicon carbide susceptor 10 through the first heat insulating member 37, the susceptor receiving member 42, and the silicon carbide susceptor 10. Heat to.

The first heat insulating member 37 is provided inside the stage 33. First heat insulating member 37 is a member for suppressing the temperature of heated silicon carbide susceptor 10 from decreasing. The upper surface of the first heat insulating member 37 is exposed from the upper surface of the stage 33.
The exhaust port 38 is provided between the outer peripheral side surface of the stage 33 and the inner wall of the film forming chamber 31. The exhaust port 38 exhausts unnecessary gas existing in the reaction space 31 </ b> A to the outside of the film forming chamber 31.

The rotation shaft 39 is disposed below the stage 33. The rotation shaft 39 has an upper end connected to the center of the stage 33 and a lower end connected to the rotation drive unit 41.
Rotation drive unit 41 rotates silicon carbide susceptor 10 fixed on stage 33 with stage 33 through susceptor receiving member 42 by rotating rotation shaft 39 in a predetermined direction.
The susceptor receiving member 42 is a member fixed on the stage 33. Susceptor receiving member 42 is a member for fixing silicon carbide susceptor 10 in a detachable state.

The ceiling plate member 43 is disposed so as to close the upper end of the film forming chamber 31. The second heating unit 44 is provided in the upper part of the ceiling plate member 43. Second heating unit 44 heats reaction space 31 </ b> A and the plurality of silicon carbide substrates 20 via second and third heat insulating members 45 and 47.
The second heat insulating member 45 is provided in the lower part of the ceiling plate member 43, and the lower surface thereof is exposed from the ceiling plate member 43. The second heat insulating member 45 suppresses the temperature of the lower part of the ceiling plate member 43 heated by the second heating unit 44 from being lowered.

The third heat insulating member 47 is disposed so as to cover the lower surface of the ceiling plate member 43 and the lower surface of the second heating unit 44. The lower surface of the third heat insulating member 47 is exposed by the reaction space 31A. The third heat insulating member 47 suppresses the temperature of the reaction space 31A from decreasing from a predetermined temperature.
The source gas lead-out part 49 penetrates the center part of the ceiling board member 43, and its end part is arranged in the reaction space 31A. The source gas outlet 49 is connected to a source gas supply source (not shown). The source gas outlet 49 supplies the source gas supplied from the source gas supply source (not shown) to the reaction space 31A.

  Thereby, a silicon carbide film 21 (for example, a 4H—SiC film) is formed on the surfaces 20 a of the plurality of silicon carbide substrates 20. At this time, the deposit 22 (refer to FIG. 4) made of silicon carbide (for example, 3C—SiC) is formed on the upper surface 11a of the susceptor body 11 and the bottom surface 12-1a of the first recess 12-1 exposed in the gap E. Accumulates. The thickness of the deposit 22 is increased by repeatedly performing the film forming process of the silicon carbide film 21 using the same silicon carbide susceptor 10.

  In the above description, the batch type silicon carbide susceptor 10 and the silicon carbide film forming apparatus 30 that can use the batch type silicon carbide susceptor 10 have been described. However, the susceptor cleaning method of the present embodiment is shown in FIG. It is also applicable to the single wafer type silicon carbide susceptor 55 shown in FIGS.

FIG. 5 is a diagram showing another silicon carbide susceptor to which the susceptor cleaning method of the present embodiment can be applied, (a) is a perspective view of the silicon carbide susceptor, and (b) is (a). It is sectional drawing of the FF line direction of the silicon carbide susceptor shown in FIG.
5A and 5B, the same components as those of the silicon carbide susceptor 10 shown in FIGS. 1 and 2 are denoted by the same reference numerals.

Here, the configuration of silicon carbide susceptor 55 will be described with reference to FIGS.
Silicon carbide susceptor 55 has a susceptor body 56 made of bulk silicon carbide and one accommodating portion 12. The susceptor body 56 has a flat upper surface 56a and a lower surface 56b, and has the same configuration as the susceptor body 11 shown in FIGS. 1 and 2 except that the outer shape is different.

  FIG. 6 is a cross-sectional view schematically showing a schematic configuration of a batch-type silicon carbide film forming apparatus in which the silicon carbide susceptor shown in FIGS. 5A and 5B can be used. In FIG. 6, the same components as those of silicon carbide susceptor 55 shown in FIGS. 5 (a) and 5 (b) are denoted by the same reference numerals.

  Referring to FIG. 6, a single-wafer silicon carbide film forming apparatus 60 includes a film forming chamber 61, a first heat insulating member 68, a second heat insulating member 69, a susceptor receiving member 71, and a third It has a heat insulating member 74, a first heating unit 76, and a second heating unit 78.

The film forming chamber 61 accommodates a first heat insulating member 68, a second heat insulating member 69, a susceptor receiving member 71, and a third heat insulating member 74. The film forming chamber 61 has a reaction space 67 between the silicon carbide susceptor 55 and the third heat insulating member 74.
Further, the film forming chamber 61 is disposed on one side wall, and is disposed on the other side wall for introducing the source gas into the reaction space 67 and the other side wall, and discharges unnecessary gas in the reaction space 67. And a gas discharge port 82 to be used.

The first heat insulating member 68 is provided in the bottom of the film forming chamber 61. First heat insulating member 68 is a member for suppressing a decrease in temperature of heated silicon carbide susceptor 55.
The second heat insulating member 69 is provided on the ceiling of the film forming chamber 61. The second heat insulating member 69 suppresses the temperature of the third heat insulating member 74 heated by the second heating unit 44 from being lowered.

The susceptor receiving member 71 is fixed on the first heat insulating member 68. On the upper surface of susceptor receiving member 71, silicon carbide susceptor 55 on which one silicon carbide substrate 20 is placed is placed. Silicon carbide susceptor 55 is fixed in a removable state with respect to susceptor receiving member 71.
The third heat insulating member 74 is provided on the lower surface of the second heat insulating member 69. The lower surface of the third heat insulating member 74 is exposed by the reaction space 67. The third heat insulating member 74 is a member for suppressing the temperature of the reaction space 67 from decreasing from a predetermined temperature.

The first heating unit 76 is disposed below the film forming chamber 61. First heating unit 76 heats silicon carbide substrate 20 to a predetermined temperature via first heat insulating member 68, susceptor receiving member 71, and silicon carbide susceptor 55.
The second heating unit 78 is disposed above the film forming chamber 61. The second heating unit 78 heats the reaction space 67 to a predetermined temperature via the second and third heat insulating members 69 and 74.

  FIG. 7 is a diagram showing a schematic configuration of a silicon carbide removing apparatus used when performing the susceptor cleaning method according to the present embodiment. FIG. 8 is a cross-sectional view of the chamber for explaining the configuration in the chamber shown in FIG.

Next, with reference to FIG.7 and FIG.8, the silicon carbide removal apparatus 90 is demonstrated.
The silicon carbide removing device 90 includes a chamber 91, a stage 93, a heating unit 95, a susceptor receiving member 97, a fluorine-containing gas supply unit 101, an oxygen-containing gas supply unit 102, a plasma generation unit 104, and a vacuum pump. 106, a gas pipe 107, an exhaust gas analysis unit 109, and a control unit 111.
It is a figure which shows the other silicon carbide susceptor which can apply the cleaning method of the susceptor of this Embodiment, (a) is a perspective view of a silicon carbide susceptor, (b) is the silicon carbide shown to (a) It is sectional drawing of the FF line direction of a susceptor. Silicon carbide removing device 90 is a device different from silicon carbide film forming devices 30 and 60 for forming silicon carbide.

The chamber 91 accommodates a stage 93, a heating unit 95, and a susceptor receiving member 97 at the bottom thereof. The chamber 91 has a reaction space 91 </ b> A between the susceptor receiving member 97 and the ceiling of the chamber 91.
In this chamber 91, a structure shown in FIG. 10E (specifically, silicon carbide susceptor 10 to which deposit 22 is attached and susceptor protection substrate 121 is placed) is housed and deposited. The plasma-generated fluorine-containing gas and oxygen-containing gas are supplied so as to come into contact with the object 22, whereby the deposit 22 deposited on the silicon carbide susceptor 10 is removed.
For this reason, the chamber 91 is preferably made of a material having sufficient resistance to the fluorine-containing gas.

The stage 93 is disposed at the bottom of the chamber 91. The heating unit 95 is disposed on the upper side of the stage 93, and the upper surface thereof is exposed from the upper surface of the stage 93.
The stage 93 may be configured to be rotatable. In this way, by making the stage 93 rotatable, it is possible to perform a more uniform removal process of the deposit 22.

  Heating unit 95 heats the plurality of silicon carbide substrates 20 to a predetermined temperature via susceptor receiving member 97 and silicon carbide susceptor 10 fixed on susceptor receiving member 97. As the heating unit 95, for example, a heater can be used.

By the way, since silicon carbide is chemically very stable, there is no sufficient removal capability simply by contacting with plasma-containing fluorine-containing gas and oxygen-containing gas.
Therefore, by providing the heating unit 95 that heats the silicon carbide susceptor 10 to which the deposit 22 is attached, the reaction between the plasma-containing fluorine-containing gas and oxygen-containing gas and the deposit 22 made of silicon carbide can be promoted. .

The heating temperature of silicon carbide susceptor 10 is preferably, for example, 300 ° C. or higher. Heating silicon carbide susceptor 10 at a very high temperature (for example, a temperature higher than 400 ° C.) is not preferable because the reaction with silicon carbide susceptor 10 becomes intense.
Further, heating the silicon carbide susceptor 10 at an excessively high temperature is not preferable because the chamber 91 reacts with the fluorine-containing gas and the oxygen-containing gas (cleaning gas).

  The susceptor receiving member 97 is fixed to the upper surface of the stage 93 and the upper surface of the heating unit 95. Susceptor receiving member 97 is a member that is fixed in a state where silicon carbide susceptor 10 is detachable.

The fluorine-containing gas supply unit 101 is connected to the plasma generation unit 104. The fluorine-containing gas supply unit 101 supplies a fluorine-containing gas to the plasma generation unit 104. The fluorine-containing gas removes silicon (silicon component) contained in silicon carbide.
Examples of the fluorine-containing gas include fluorine (F ₂ -GWP: 0), hydrogen fluoride (HF-GWP: 0), hydrofluorocarbon (CxHyFz (x, y, z are integers of 1 or more), CH ₃ F- Among GWP-97), one containing at least one can be used.

Examples of the fluorine-containing gas include fluorocarbon (CF ₄ -GWP: 7,390, C ₂ F ₆ -GWP: 12,200), sulfur hexafluoride (SF ₆ -GWP: 22,800), and three fluorine. Nitrogen bromide (NF ₃ -GWP: 17,200), chlorine trifluoride (ClF ₃ -GWP: 0), carbonyl difluoride (COF ₂ -GWP: 1) and the like can also be used.
However, since these gases have a large global warming potential (GWP), they are not so preferable from the viewpoint of global warming. A low environmental load gas such as F ₂ or HF having a small GWP value is preferred.

The oxygen-containing gas supply unit 102 is connected to the plasma generation unit 104. The oxygen-containing gas supply unit 102 supplies an oxygen-containing gas to the plasma generation unit 104.
The oxygen-containing gas supply unit 102 is connected to the plasma generation unit 104 in a state in which only the oxygen-containing gas or an oxygen-containing gas mixed with the fluorine-containing gas supplied from the fluorine-containing gas supply unit 101 can be supplied. Yes. The oxygen-containing gas is a gas that removes carbon (carbon component) contained in silicon carbide.

Examples of the oxygen-containing gas include oxygen (O ₂ ), ozone (O ₃ ), nitrogen oxide (NxOy (x and y are integers of 1 or more)), water vapor (H ₂ O), carbon dioxide (CO ₂ ). A gas containing at least one gas among carbon monoxide (CO) can be used.

  The plasma generation unit 104 is connected to the fluorine-containing gas supply unit 101 and the oxygen-containing gas supply unit 102. The plasma generation unit 104 converts the fluorine-containing gas and the oxygen-containing gas into plasma, and supplies the plasma-containing fluorine-containing gas and oxygen-containing gas into the chamber 91 (reaction space 91A).

  In order to efficiently convert the fluorine-containing gas and oxygen-containing gas, which are cleaning gases, into plasma, an inert gas such as Ar, He, Ne or the like may be added as a discharge gas to the fluorine-containing gas and the oxygen-containing gas. Good.

  The vacuum pump 106 is connected to the chamber 91 and the gas pipe 107. The vacuum pump 106 exhausts the gas in the chamber 91 and guides the exhaust gas to the gas pipe 107. The gas pipe 107 is connected to the vacuum pump 106 and the exhaust gas analysis unit 109.

  The exhaust gas analysis unit 109 is connected to the gas pipe 107. The exhaust gas analyzer 109 is a gas analyzer that measures the concentration of silicon tetrafluoride and / or the concentration of carbon dioxide contained in the exhaust gas. The exhaust gas analysis unit 109 is connected to the control unit 111 and transmits the measured concentration of silicon tetrafluoride or carbon dioxide to the control unit 111.

As the exhaust gas analysis unit 109, for example, a non-dispersive infrared analyzer may be used. In this way, by using a non-dispersive infrared analyzer as the exhaust gas analyzer 109, the concentrations of silicon tetrafluoride and carbon dioxide can be measured easily and at low cost.
As the exhaust gas analysis unit 109, for example, an analyzer such as a Fourier transform infrared spectrometer, an ultraviolet absorber, a mass spectrometer, or a gas chromatograph may be used.

  The control unit 111 is electrically connected to the heating unit 95, the fluorine-containing gas supply unit 101, the oxygen-containing gas supply unit 102, the plasma generation unit 104, and the exhaust gas analysis unit 109.

Control unit 111 performs overall control of silicon carbide removing device 90. For example, based on the concentration of silicon tetrafluoride or the concentration of carbon dioxide transmitted from the exhaust gas analysis unit 109, the control unit 111 generates a plasma generation unit 104, a heating unit 95, a fluorine-containing gas supply unit 101, and an oxygen-containing gas. The supply unit 102 is controlled.
The control unit 111 includes a storage unit and a calculation unit that are not shown. The storage unit stores a silicon tetrafluoride concentration threshold value or a carbon dioxide concentration threshold value inputted in advance.

  In addition, in the calculation unit (not shown), the silicon tetrafluoride concentration threshold value input in advance or the carbon dioxide concentration threshold value and the silicon tetrafluoride generated in the first and second steps described later are used. The chamber 91, the heating unit 95, and the fluorine-containing gas supply unit are stopped so that the processing of the first and second steps is stopped when the concentration or the concentration of carbon dioxide is compared and the concentration is below the threshold value. 101 and the oxygen-containing gas supply unit 102 are controlled.

FIG. 9 is a flowchart for explaining the susceptor cleaning method according to the present embodiment.
FIG. 10 is a view for explaining each step constituting the susceptor cleaning method according to the present embodiment. FIG. 10A is a cross-sectional view of the main part of the prepared silicon carbide susceptor. FIG. 10B is a cross-sectional view of the silicon carbide susceptor arranged in the film forming chamber of the silicon carbide film forming apparatus and having the silicon carbide substrate placed on the silicon carbide susceptor housing.
FIG. 10C is a cross-sectional view of a silicon carbide susceptor in which a deposit made of silicon carbide is deposited after a silicon carbide film is formed on the surface of the silicon carbide substrate, and the silicon carbide substrate. FIG. 10D is a cross-sectional view of the silicon carbide susceptor in which the silicon carbide substrate on which the silicon carbide film is formed is collected, taken out from the film formation chamber of the silicon carbide film formation apparatus, and the deposit is deposited.
FIG. 10E is a cross-sectional view of the silicon carbide susceptor that is housed in the chamber of the silicon carbide removing device, the silicon carbide susceptor protective substrate is disposed in the housing portion, and the deposit is deposited, and the susceptor protective substrate. FIG. 10F is a cross-sectional view of the silicon carbide susceptor after the deposit is removed.
10 (a) to 10 (f), the same components as those shown in FIGS. 1, 2 (a), 2 (b), 3 and 4 are denoted by the same reference numerals.

Next, with reference to FIG. 9 and FIGS. 10A to 10F, a susceptor cleaning method according to the present embodiment when the silicon carbide removing apparatus 90 shown in FIG. 7 is used will be described.
First, when the process shown in FIG. 9 is started, in STEP 1 (step shown in FIG. 10A), the plurality of parts shown in FIG. 1, FIG. 2A, FIG. And a silicon carbide susceptor 10 made of bulk silicon carbide. Thereafter, the process proceeds to STEP2.

As described above, by preparing the silicon carbide susceptor 10 made of bulk silicon carbide, the problem (specifically, the member 300-1 made of carbon as described above with reference to FIGS. 14A and 14B). When the susceptor body 301 coated with a coating 300-2 made of a silicon carbide film is washed with liquid, the liquid soaks into the member 300-1 made of carbon, and the liquid expands due to heat. It is possible to suppress the occurrence of the problem of damage.
Thus, the etching used in STEPs 5 and 6 remaining on the surface of the silicon carbide susceptor 10 after STEPs 5 and 6 shown in FIG. 9 by the treatment using the liquid (specifically, the RCA cleaning performed in STEP 9 shown in FIG. 9). Components (for example, F component and N component) contained in the gas (plasma-containing fluorine-containing gas and oxygen-containing gas) can be removed.

  In STEP 1, a silicon carbide susceptor 10 made of bulk silicon carbide having an average surface roughness Ra of 1 μm or less (more preferably 0.5 μm or less) is prepared by using the mirror polishing described above. .

  Next, in STEP 2 (steps shown in FIGS. 10B and 10C), the silicon carbide susceptor 10 is disposed in the film forming chamber 31 of the silicon carbide film forming apparatus 30 shown in FIG. After the silicon carbide substrate 20 is placed in the housing portion 12, a silicon carbide film 21 (for example, a 4H—SiC film) is formed on the surfaces 20 a of the plurality of silicon carbide substrates 20 using predetermined film formation conditions. Thereafter, the step of carrying out silicon carbide substrate 20 on which silicon carbide film 21 is formed is repeated until a predetermined condition is satisfied.

As the predetermined condition, for example, the total time (predetermined period) of the deposition time of the silicon carbide film 21 or the total film thickness of the silicon carbide film 21 after the use of the silicon carbide susceptor 10 is started. be able to.
In STEP 2, thresholds such as the total time (predetermined period) of the deposition time of the silicon carbide film 21 and the total thickness of the silicon carbide film 21 after the start of use of the silicon carbide susceptor 10 are set in advance. When the threshold value is exceeded, the processing of STEP2 is terminated.

Even in the process of forming the silicon carbide film 21 once, the surface 11a of the susceptor body 11 and the bottom surface 12-1a of the first recess 12-1 exposed in the gap E are made of silicon carbide (for example, 3C-SiC film). Deposit 22 is deposited, but by repeating the above steps, silicon carbide susceptor 10 (specifically, bottom surface 12-of first recess 12-1 exposed at surface 11 a of susceptor body 11 and gap E). In 1a), a thick deposit 22 (for example, 45 to 200 μm or more) is deposited.
When the process of STEP2 is completed, the process proceeds to STEP3.

  Next, in STEP 3 (step shown in FIG. 10 (d)), a plurality of silicon carbide substrates 20 (FIG. 10 (c) in which the silicon carbide film 21 is formed from the film forming chamber 31 of the silicon carbide film forming apparatus 30 shown in FIG. )) Is collected, the silicon carbide susceptor 10 on which the deposit 22 made of silicon carbide is deposited is taken out from the film forming chamber 31. Thereafter, the process continues to STEP4.

  At this stage, as shown in FIG. 10 (d), deposition is performed on the upper surface 11a of the susceptor body 11 and the bottom surface 21-1a of the first recess 21-1 exposed in the gap E (see FIG. 10 (c)). Object 22 is deposited.

Next, in STEP 4 (step shown in FIG. 10E), the silicon carbide susceptor 10 on which the deposit 22 is deposited is fixed to the susceptor receiving member 97 disposed in the chamber 91 of the silicon carbide removing apparatus 90 shown in FIG. .
Next, the susceptor protective substrate 121 having the same shape as that of the silicon carbide substrate 20 is placed in the portion of the first recess 12-1 where the silicon carbide substrate 20 is disposed (see FIG. 10C). To do. Thereafter, the process proceeds to STEP5.

  In this way, by placing the susceptor protection substrate 121 in the first recess 12-1 where the silicon carbide substrate 20 has been disposed, dry etching (to be described later, plasma-modified fluorine-containing gas performed in STEP 5) is performed. It is possible to prevent the silicon carbide susceptor 10 positioned below the susceptor protection substrate 121 from being etched by the etching process used and the etching process using the oxygen-containing gas that has been converted into plasma performed in STEP 6.

  Therefore, as the material of the susceptor protective substrate 121, it is preferable to use a material having resistance to plasma-containing fluorine-containing gas and plasma-ized oxygen-containing gas. As such a material, for example, silicon carbide, nitrogen carbide, and sapphire can be used.

  Of the above materials, nitrogen contained in nitrogen carbide and aluminum contained in sapphire are impurities that adversely affect the formation of the silicon carbide film 21, and therefore from the viewpoint of impurities, the susceptor protective substrate 121. As the material, single crystal silicon carbide having high purity (purity of 99.9999% or more), polycrystalline silicon carbide, and sintered silicon carbide are more preferable.

In addition, as a material of the susceptor protection substrate 121, for example, inexpensive quartz (specifically, synthetic quartz or high-purity (purity of 99.9999% or more) fused quartz) may be used. Quartz does not have good resistance to plasma-containing fluorine-containing gas and plasma-ized oxygen-containing gas, but there is no problem of impurities as described above.
For this reason, it is possible to use an inexpensive susceptor protection substrate 121 by forming the susceptor protection substrate 121 with a sufficient thickness using quartz.

  The susceptor protection substrate 121 can be used repeatedly, and when it is damaged, it is replaced with a new susceptor protection substrate 121.

  Next, in STEP 5, silicon contained in the deposit 22 made of silicon carbide deposited on the silicon carbide susceptor 10 is selectively removed by dry etching that supplies a plasma-containing fluorine-containing gas (first step).

At this time, the plasma-containing fluorine-containing gas is supplied in a direction from the upper side of the chamber 91 to the lower side of the chamber 91, but the plasma-containing fluorine-containing gas is not guided to advance in the vertical direction. For this reason, some of the plasma-containing fluorine-containing gas goes in the vertical direction, and some goes in a direction other than the vertical direction.
In STEP 5, silicon contained in the deposit 22 reacts with the fluorine-containing gas to become silicon tetrafluoride, which is desorbed and removed.

In the first step, the time change of the concentration of silicon tetrafluoride, which is the exhaust gas discharged from the chamber 91, is measured by the exhaust gas analyzer 109, and after the concentration of silicon tetrafluoride reaches the maximum value, the measurement is performed for 5-10. The process is terminated when the concentration of silicon tetrafluoride continuously changes in the time interval. Thereafter, the process continues to STEP6.
The reason why the concentration of silicon tetrafluoride gradually decreases is that the reaction on the surface of the deposit 22 is reduced and carbon is increased, thereby preventing the reaction.

  Next, in STEP 6, carbon contained in the deposit 22 is selectively removed by dry etching by supplying plasma-containing oxygen-containing gas to the deposit 22 made of silicon carbide deposited on the silicon carbide susceptor 10. (Second step).

At this time, the plasma-containing oxygen-containing gas is supplied in a direction from above the chamber 91 toward the bottom of the chamber 91, but the plasma-containing oxygen-containing gas is not guided to advance in the vertical direction. For this reason, some oxygen-containing gases that have been made into plasma are directed in the vertical direction, while others are directed in directions other than the vertical direction.
In STEP 6, the carbon contained in the deposit 22 reacts with the oxygen-containing gas to become carbon dioxide, which is desorbed and removed.

  Further, in the second step, the time change in the concentration of carbon dioxide discharged from the chamber 91 is measured by the exhaust gas analysis unit 109, and continuously from 5 to 10 measurement time intervals from when the carbon dioxide concentration reaches the maximum value. The process is terminated when the concentration of carbon dioxide becomes negative. The process then continues to STEP7.

The reason why the concentration of carbon dioxide gradually decreases is that the carbon on the surface of the deposit 22 decreases and silicon increases, thereby preventing the reaction.
Further, as the concentration of silicon tetrafluoride and the concentration of carbon dioxide, values obtained by adding arithmetic processing such as moving average may be used. Thereby, it becomes possible to grasp the behavior change of the stable density | concentration.

Next, in STEP 7, it is determined whether or not the concentration of silicon tetrafluoride contained in the exhaust gas is equal to or lower than a preset threshold value.
In STEP 7, when it is affirmatively determined (determined as Yes) that the concentration of silicon tetrafluoride is equal to or lower than a preset threshold value, the process proceeds to STEP 8.
Moreover, when the negative determination (determined as No) that the concentration of silicon tetrafluoride is not lower than the preset threshold value is made in STEP 7, the process returns to STEP 5 and the processes of the first and second steps ( (Steps 5 and 6) are performed, and the process proceeds to STEP 7 again.

That is, in STEP 7, the first and second steps are repeatedly performed until an affirmative determination is made, thereby removing silicon contained in the deposit 22 made of silicon carbide and removing carbon contained in the deposit 22. Repeat.
In other words, the deposit 22 made of silicon carbide deposited on the silicon carbide susceptor 10 is removed by repeating the first and second steps. Thereby, as shown in FIG.10 (f), the upper surface 11a of the susceptor main body 11 and the bottom face 12-1a of the 1st recessed part 12-1 are exposed.

By the way, when the removal of the deposit 22 approaches the end, the concentration of silicon tetrafluoride generated in the first step and the concentration of carbon dioxide generated in the second step gradually decrease.
Therefore, as described in STEP 7 above, when the concentration of silicon tetrafluoride is equal to or lower than a preset threshold value, the processing of the first and second steps is ended, so that the silicon carbide susceptor 10 includes: The deposit 22 deposited on the silicon carbide susceptor 10 can be accurately removed without damaging the portion covered with the deposit 22.

  Further, as the above-mentioned threshold value of the concentration of silicon tetrafluoride (a preset threshold value), for example, the concentration of silicon tetrafluoride is higher than the maximum value of the concentration of silicon tetrafluoride detected in the first step. A value of 1/10 or less can be used.

  Further, the threshold value of the silicon tetrafluoride concentration is determined in advance by the relationship between the silicon carbide amount of a certain amount and the removal processing speed (the maximum value of the silicon tetrafluoride concentration in the first step, the first and second values). It can be arbitrarily set according to the amount of silicon carbide in the initial stage and the target silicon carbide removal processing amount after grasping the relationship between the concentration of silicon tetrafluoride when the steps are repeated.

  Further, the threshold value of the concentration of silicon tetrafluoride is stored in advance in the control unit 111 (specifically, a storage unit (not shown)) shown in FIG. A comparison is made between the concentration of silicon tetrafluoride detected by 109 and the threshold value of the concentration of silicon tetrafluoride, and based on this result, the control unit 111 controls the chamber 91, the fluorine-containing gas supply unit 101, and the oxygen-containing concentration. Control of the gas supply unit 102 and the plasma generation unit 104 is performed.

  In FIG. 9, the case where it is determined in STEP 7 whether or not the concentration of silicon tetrafluoride is equal to or lower than the threshold has been described as an example. In STEP 7, whether the concentration of carbon dioxide is equal to or lower than the threshold. It may be determined whether or not. In this case, the same effect as in the case where it is determined in STEP 7 whether or not the concentration of silicon tetrafluoride has become equal to or lower than the threshold value can be obtained.

Further, as the exhaust gas analyzer 109 for measuring the concentrations of silicon tetrafluoride and carbon dioxide, a non-dispersive infrared analyzer may be used.
Thus, by using a non-dispersive infrared analyzer as the exhaust gas analyzer 109 for measuring the concentrations of silicon tetrafluoride and carbon dioxide, the time required to collect one data is several seconds longer if it is short. Since it takes several tens of seconds, the deposit 22 is efficiently removed by providing a response time of 10 measurement time intervals when the data collection time is short and 5 measurement intervals when the data collection time is long. Can be performed.

In the present embodiment, the components generated from the deposit 22 made of silicon carbide are specified as silicon tetrafluoride and carbon dioxide, but one of these is silicon tetrafluoride and carbon dioxide. It occupies most of the product.
Another reason is that the removal reaction conditions for mainly generating silicon tetrafluoride and carbon dioxide are such that the concentration of the fluorine-containing gas component is low, the heating temperature can be set low, and good removal performance is achieved. It is because it can obtain.

  However, for example, when a considerable amount of carbon tetrafluoride is generated by the reaction between the deposit 22 made of silicon carbide and the fluorine-containing gas, carbon tetrafluoride is added to carbon dioxide as carbon derived from silicon carbide, and the end point is reached. The deposit 22 can be removed with higher accuracy by adjusting the control mechanism for detection and end point detection.

Next, in STEP 8, the cleaning process (removal process) of the deposit 22 deposited on the silicon carbide susceptor 10 is stopped, and a plurality of susceptor protection substrates 121 (see FIG. 10E) placed on the silicon carbide susceptor 10 are stopped. to recover.
Thereafter, silicon carbide susceptor 10 from which deposit 22 has been removed (silicon carbide susceptor 10 shown in FIG. 10F) is taken out from chamber 91 of silicon carbide removing apparatus 90 shown in FIG. Thereafter, the process proceeds to STEP9.

Next, in STEP 9, the silicon carbide susceptor 10 shown in FIG. 10 (f) is RCA cleaned. Specifically, first, for example, the silicon carbide susceptor 10 is immersed in a dilute hydrofluoric acid aqueous solution (HF) having a concentration of 5% for a predetermined time (for example, 600 seconds) and cleaned with pure water.
Next, a mixed solution (ammonia water: hydrogen peroxide) in which 28% ammonia water (NH ₄ OH), 30% hydrogen peroxide water (H ₂ O ₂ ), and water (H ₂ O) are mixed. Pure water cleaning is performed by immersing the silicon carbide susceptor 10 in a predetermined time (for example, 600 sec) in water: water = 1: 1: 5 mixing ratio).

  Thereby, foreign matters, organic substances, particles, impurity metals, and the like are removed from the surface of silicon carbide susceptor 10. When the process of STEP9 is completed, the process proceeds to STEP10.

Next, in STEP 10, the silicon carbide susceptor 10 is washed with ultrapure water (for example, pure water having a specific resistance value of 18.1 MΩ or more), whereby a chemical solution (dilute hydrofluoric acid aqueous solution (HF) and Components contained in ammonia (NH ₄ OH) and hydrogen peroxide (H ₂ O ₂ ) are removed.
At this time, components (for example, F component and N component) contained in the etching gas remaining on the surface of the silicon carbide susceptor 10 (plasma-containing fluorine-containing gas and oxygen-containing gas used in STEPs 5 and 6) are also removed. can do. Thereafter, the process proceeds to STEP11.

  Next, in STEP 11, the silicon carbide susceptor 10 wet with pure water is dried. As a drying method, for example, a spin drying method can be used. Thereby, the process illustrated in FIG. 9 ends. Silicon carbide susceptor 10 from which deposit 22 has been removed is used again in film formation chamber 31 of silicon carbide film formation apparatus 30 shown in FIG.

According to the susceptor cleaning method of the present embodiment, by using silicon carbide susceptor 10 composed only of bulk silicon carbide, even if silicon carbide susceptor 10 is etched in the etching process, Since carbon is not used as a material, carbon is not exposed. Thereby, it can suppress that the silicon carbide film | membrane 21 formed in the silicon carbide substrate 20 is contaminated with carbon.
Further, by using silicon carbide susceptor 10 composed only of bulk silicon carbide, silicon carbide susceptor 10 can be cleaned using a liquid.

Bulk silicon carbide has a surface roughness value smaller than that of a silicon carbide film as a film, and thus is difficult to be etched in the etching process. For this reason, it is possible to reduce the amount of etching (etching amount) of silicon carbide susceptor 10 in the repeated processing (etching step) in the first and second steps.
Therefore, silicon carbide susceptor 10 from which deposit 22 has been removed can be used again to form silicon carbide film 21 having good film quality.

  Furthermore, the silicon carbide susceptor 10 from which the deposits 22 have been removed by the first and second steps is cleaned by RCA, and then cleaned by ultra pure water, so that an etching gas (fluorinated fluorine-containing gas and oxygen-containing gas) is obtained. Since components (for example, F component and N component) contained in the gas) can be removed, contamination of the silicon carbide film 21 due to the etching gas can be suppressed.

  The susceptor cleaning method is particularly effective in removing a thick deposit deposited on the silicon carbide susceptor 10 by an ex-situ dry cleaning.

  In the susceptor cleaning method of the present embodiment, as shown in FIG. 9, as an example, the deposit 22 is removed by alternately performing the first step and the second step. As described above, the deposit 22 may be removed by simultaneously performing the first and second steps. In this case, the concentration of silicon tetrafluoride contained in the exhaust gas is measured continuously from the start of the first and second steps, and it is determined whether or not the concentration of silicon tetrafluoride has become a predetermined threshold value or less. Done.

Thus, when removing the deposit 22 by simultaneously performing the first and second steps, the same effect as the susceptor cleaning method of this embodiment (the cleaning method comprising the process shown in FIG. 11) is obtained. Can be obtained.
That is, in the susceptor cleaning method of the present embodiment, the first and second steps may be performed alternately or simultaneously.

  The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to such specific embodiments, and within the scope of the present invention described in the claims, Various modifications and changes are possible.

(Example)
<Preparation process of silicon carbide susceptor>
In the example, the silicon carbide susceptor 10 shown in FIGS. 1, 2A, 2B, and 3 was used as a susceptor on which a plurality of silicon carbide substrates 20 are placed.
As silicon carbide substrate 20, a single crystal silicon carbide wafer having a diameter of 3 inches (7.62 cm) and a thickness of 350 μm was used.

As a material of the silicon carbide susceptor 10, bulk silicon carbide was used. Moreover, it was 0.39 micrometer when the average surface roughness Ra of the silicon carbide susceptor 10 was measured using the AFM apparatus (NX-10 by Hitachi High-Technology Co., Ltd.).
In addition, the outer diameter of the susceptor body 11 is 300 cm, the thickness of the susceptor body 11 where the housing portion 12 is not disposed is 3 mm, and the opening diameter of the first recess 12-1 is 7.82 cm (in other words, a ring shape) The width of the gap E is 1 mm), the depth of the first recess 12-1 is 350 μm, which is the same as that of the silicon carbide substrate 20, and the depth of the second recess 12-2 is 1 mm.

Moreover, the silicon carbide susceptor is brought into contact with the surface from the outermost periphery of silicon carbide substrate 20 to the inner side 1 mm of bottom surface 20b of silicon carbide substrate 20 and bottom surface 12-1a of first recess 12-1. Silicon carbide substrate 20 was placed in a plurality of housing portions 12 (specifically, first recesses 12-1) provided in 10.
At this time, the surface 20 a of the silicon carbide substrate 20 arranged in the plurality of accommodating portions 12 was made flush with the upper surface 11 a of the susceptor body 11.

<Silicon Carbide Film Forming Process on Multiple Silicon Carbide Substrates>
Next, silicon carbide susceptor 10 is housed in film forming chamber 31 of silicon carbide film forming apparatus 30 (manufactured by Taiyo Nippon Sanso Corporation) shown in FIG. 4, and silicon carbide films are formed on surfaces 20 a of a plurality of silicon carbide substrates 20. 21, the process of forming (epitaxially growing) a 4H—SiC film having a thickness of 10 μm was repeated 15 times.

At this time, SiH ₄ (supply amount is 240 sccm) and C ₃ H ₈ (supply amount is 180 sccm) were used as source gases. As the carrier gas, H ₂ (supply amount is 1000 sccm) was used. The temperature in the film forming chamber 31 during epitaxial growth was 1600 ° C.

  By carrying out the step of forming the 4H—SiC film, it is confirmed that the deposit 22 (see FIG. 10C) made of silicon carbide has accumulated in the gap E, and the upper surface 11a of the susceptor body 11 is formed. It was confirmed that a deposit 22 (a deposit made of silicon carbide (3C—SiC)) having a thickness of 200 μm was deposited.

<Cleaning step for removing deposits deposited on silicon carbide susceptor>
Next, silicon carbide susceptor 10 on which deposit 22 was deposited was taken out from silicon carbide film forming apparatus 30 shown in FIG. Next, the silicon carbide susceptor 10 in which the deposit 22 is deposited on the susceptor receiving member 97 (see FIG. 8) disposed in the chamber 91 of the silicon carbide removing apparatus 90 (manufactured by Taiyo Nippon Sanso Corporation) shown in FIG. And a cleaning process for removing the deposit 22 was performed.

  As the cleaning process, the cleaning method described with reference to FIG. 9 and FIG. 10 is used to supply the fluorine-containing gas that has been made plasma into the chamber 91, whereby the deposit 22 made of silicon carbide is applied. A first step of selectively removing the silicon component contained therein, and a second step of selectively removing the carbon component contained in the deposit 22 by supplying an oxygen-containing gas that has been converted into plasma into the chamber 91. By repeatedly performing the steps and sequentially, the deposit 22 deposited on the silicon carbide susceptor 10 was removed.

At this time, NF ₃ (supply amount was 100 sccm) was used as the fluorine-containing gas, and O ₂ (supply amount was 500 sccm) was used as the oxygen-containing gas. The temperature in the chamber 91 during the cleaning process was set to 300 ° C.

  It was confirmed that silicon carbide susceptor 10 was hardly etched after removal of deposit 22 was completed.

<RCA cleaning, ultrapure water cleaning, and drying process>
Next, RCA cleaning was performed on silicon carbide susceptor 10 from which deposit 22 was removed. Specifically, silicon carbide susceptor 10 from which deposit 22 was removed was immersed in 5% dilute hydrofluoric acid. At this time, the temperature of 5% dilute hydrofluoric acid was set to 70 ° C.
Thereafter, silicon carbide susceptor 10 was taken out of 5% dilute hydrofluoric acid, and silicon carbide susceptor 10 was cleaned for 2 minutes by ultrasonic cleaning using ion-exchanged water. At this time, the ion-exchanged water is a city water that is raw water using Milli-DI, which is an ion-exchange water production cartridge manufactured by Merck Co., Ltd. (water that includes water other than drinking water. ) Was purified by filtration.
For ultrasonic cleaning, WT-300M (model number) manufactured by Yamato Scientific Co., Ltd. was used.

  Next, the silicon carbide susceptor 10 from which the deposit 22 was removed was immersed in a mixed solution mixed under the conditions of ammonium hydroxide: hydrogen peroxide: water = 1: 1: 5. At this time, the temperature of the liquid mixture was set to 70 ° C., and the silicon carbide susceptor 10 was immersed for 10 minutes. Thereafter, silicon carbide susceptor 10 was taken out, and silicon carbide susceptor 10 was cleaned for 2 minutes by ultrasonic cleaning using ion-exchanged water.

Next, silicon carbide susceptor 10 was cleaned for 2 minutes by ultrasonic cleaning using ion-exchanged water. Next, silicon carbide susceptor 10 was cleaned for 2 minutes by running water cleaning using ultrapure water (specifically, pure water having a specific resistance value of 18.1 MΩ or more).
Next, silicon carbide susceptor 10 is placed in a vacuum drying furnace (not shown). Next, the temperature in the vacuum drying furnace (not shown) is 120 ° C., and the degree of vacuum in the vacuum drying furnace (not shown) is 5 × 10 ⁻⁵ Pa · m · S ⁻¹ or more. The silicon carbide susceptor 10 was dried by holding for 12 hours or more.

<Silicon Carbide Film Forming Process on Multiple Silicon Carbide Substrates Using Silicon Carbide Susceptor After Drying Process>
Next, a plurality of silicon carbide substrates 20 are placed on a plurality of silicon carbide substrates 20 using silicon carbide susceptor 10 after the drying step, and the silicon carbide film described above is formed on surfaces 20a of the plurality of silicon carbide substrates 20. The same process as the film forming process 91 (specifically, a process of forming a 10 μm 4H—SiC film 15 times) was performed.
In the example, the epi-defect of the 4H—SiC film was not confirmed in the fifteen deposition processes. From this, it is possible to form a good 4H—SiC film by reusing the silicon carbide susceptor 10 in which the deposit 22 is removed by the etching process and the RCA cleaning, the pure water cleaning, and the drying process are performed. It could be confirmed.

(Comparative example)
<Preparation process of susceptor>
FIG. 11 is a plan view showing a schematic configuration of the susceptor used in the comparative example. 12 is a cross-sectional view of the susceptor shown in FIG. 11 in the GG line direction. In FIG. 12, for convenience of explanation, silicon carbide substrate 20 not shown in FIG. 11 is shown by a dotted line.

In the comparative example, susceptor 250 shown in FIGS. 11 and 12 was used as a susceptor on which a plurality of silicon carbide substrates 20 are placed.
Here, with reference to FIG.11 and FIG.12, the structure of the susceptor 250 used by a comparative example is demonstrated.
The susceptor 250 includes a susceptor main body 251 and a plurality of accommodating portions 252. The plurality of accommodating portions 252 were arranged at equal intervals so that the centers of the accommodating portions 252 were positioned on the circumference centered on the center N of the susceptor body 251.

  Accommodating portion 252 is disposed below first recess 252-1, which is a space in which silicon carbide substrate 20 is disposed, and below first recess 252-1, and has an opening diameter larger than that of first recess 252-1. The second recess 252-2 is a small space integrated with the first recess 252-1.

Silicon carbide substrate 20 was placed such that gap P between outer peripheral edge 20A and the side wall of first recess 252-1 was 1 mm.
First recess 252-1 had an external total of 7.82 cm (in other words, gap P was 1 mm) and a depth of 350 μm, which is the same as the thickness of silicon carbide substrate 20. The depth of the second recess 252-2 was 1 mm.
As the susceptor 250, a carbon member coated with a 200 μm thick silicon carbide film was used.

<Silicon Carbide Film Forming Process on Multiple Silicon Carbide Substrates>
Next, the susceptor 250 is accommodated in the film forming chamber 31 of the silicon carbide film forming apparatus 30 (manufactured by Taiyo Nippon Sanso Corporation) shown in FIG. 4, and a silicon carbide film is formed on the surfaces 20a of the plurality of silicon carbide substrates 20 as The process of forming (epitaxially growing) a 4H—SiC film having a thickness of 10 μm was repeated 15 times.
The conditions for forming the 4H—SiC film at this time were the same as in the example.

  By performing the step of forming the 4H—SiC film, it is confirmed that a deposit made of silicon carbide is deposited in the gap P, and a deposit (silicon carbide) having a thickness of 200 μm is formed on the upper surface 251a of the susceptor body 251. It was confirmed that a deposit comprising

<Cleaning process to remove deposits deposited on susceptor>
Next, susceptor 250 on which deposits were deposited was taken out from silicon carbide film forming apparatus 30 shown in FIG. Next, on the susceptor receiving member 97 (see FIG. 8) disposed in the chamber 91 of the silicon carbide removing apparatus 90 (manufactured by Taiyo Nippon Sanso Corporation) shown in FIG. A cleaning process (dry etching process in which the first and second steps are repeated) for fixing 250 and removing the deposit was performed.
As conditions for the dry etching process, the same conditions as in the examples were used.

  After the removal of the deposit is completed, it can be confirmed that the side wall of the first recess 252-1 constituting the susceptor 250 is etched to reduce the thickness, and the carbon is exposed from the silicon carbide film as the coating material. It was. That is, it was confirmed that the susceptor 250 was damaged by dry etching.

<Step of Forming Silicon Carbide Film on Multiple Silicon Carbide Substrates Using Cleaned Susceptor>
Next, the plurality of silicon carbide substrates 20 are placed on the damaged susceptor 250, and the same process as the silicon carbide film formation process described above (specifically, the surface 20a of the plurality of silicon carbide substrates 20 is specifically described). A process of forming a 10 μm 4H—SiC film 15 times).
In the comparative example, the epi-defect of the 4H—SiC film was confirmed after the fifth time. This is considered to be because a 4H—SiC film was formed using the damaged susceptor 250.

(Experimental example)
Here, samples 1 to 8 cut out from the portion of the susceptor where the silicon carbide substrate 20 is not placed are prepared, the average surface roughness Ra (μm) of each sample, and the etching rate (μm) of each sample. / Min).
The outer diameters of Samples 1 to 8 were 10 mm long × 10 mm wide × 2 mm high.

The results are shown in Table 1 and FIG. FIG. 13 is a graph of the results shown in Table 1.
FIG. 13 is a graph showing the relationship between the average surface roughness Ra (μm) and the etching rate (μm / min) of porous silicon carbide, silicon carbide coat (with or without polishing), and bulk silicon carbide (with or without polishing). .

Sample 1 is sintered at normal pressure by heating SiC fine powder (average particle size of 1 to 100 μm) and Si fine powder (average particle size of 1 to 100 μm) at a temperature of 1500 ° C. at normal pressure. That was formed.
Sample 2 is sintered at normal pressure by heating SiC fine powder (average particle size of 1 to 100 μm) and Si fine powder (average particle size of 1 to 100 μm) at a temperature of 1800 ° C. at normal pressure. That was formed.

Sample 3 was formed by coating bulk carbon with a silicon carbide coating film (thickness: 200 μm). Sample 4 was formed by preparing the same material as Sample 3, and then polishing the surface for 5 minutes using # 3000 sandpaper having abrasive grains having an average particle diameter of 4 to 8 μm.
Sample 5 was formed by preparing the same material as Sample 3, and then polishing the surface for 5 minutes using # 8000 sandpaper having abrasive grains having an average particle diameter of 2 to 4 μm.

Sample 6 was formed by pressure sintering in which temperature (2000 ° C.) and pressure (50 MPa) were applied to SiC fine powder (average particle size is 0.1 to 10 μm).
Sample 7 was produced by buffing the surface of bulk silicon carbide formed by the same method as Sample 6. At this time, for buffing, # 400 abrasive grains were used, and a cloth was used as the polishing cloth. The buffing time was 5 min.
Sample 8 was fabricated by mirror polishing the surface of bulk silicon carbide formed by the same method as Sample 6. At this time, # 800 abrasive grains were used for mirror polishing, and a blanket was used as the polishing cloth. The mirror polishing time was 5 min.

Moreover, as an apparatus which measures the average surface roughness Ra (micrometer) of the samples 1-8, ET4000A which is a stylus type step meter made by Kosaka Laboratory Ltd., and AFM (made by Hitachi High-Technologies Corporation) NX-10, an Atomic Force Microscope) device, was used.
In addition, when average surface roughness Ra is 1 μm or more, ET4000A which is a stylus type step meter manufactured by Kosaka Laboratory Co., Ltd. is used, and when average surface roughness Ra is 1 μm or less, NX manufactured by Hitachi High-Technologies Corporation. -10 was used.

Subsequently, the etching process of the surface of the said samples 1-8 in which average surface roughness Ra was measured was performed.
Specifically, the average surface roughness Ra is measured on the susceptor receiving member 97 (see FIG. 8) disposed in the chamber 91 of the silicon carbide removing device 90 (manufactured by Taiyo Nippon Sanso Corporation) shown in FIG. After fixing the above-described samples 1 to 8, the surfaces of samples 1 to 8 were etched.

  At this time, as the etching process, the cleaning method described above with reference to FIG. 9 was used. Specifically, a first step of selectively removing silicon components contained in the surfaces of samples 1 to 8 made of silicon carbide by supplying a fluorine-containing gas into plasma into the chamber 91, and the chamber The surfaces of Samples 1 to 8 were etched by sequentially repeating the second step of selectively removing the carbon component contained on the surface by supplying oxygen-containing gas that was converted into plasma into 91.

Further, NF ₃ (supply amount is 100 sccm) was used as the fluorine-containing gas, and O ₂ (supply amount was 500 sccm) was used as the oxygen-containing gas. The temperature in the chamber 91 during the cleaning process was set to 300 ° C.

  The etching rates of samples 1 to 8 shown in Table 1 were observed by observing the cross sections of samples 1 to 8 before and after etching using TM3030, which is a scanning electron microscope (SEM) manufactured by Hitachi High-Technology Corporation. Based on the observation, the change in thickness of each of the samples 1 to 8 before and after the etching was obtained, and this was calculated by dividing this by the etching time (total etching time consisting of the first and second steps).

Referring to Table 1, the etching rate of a silicon carbide susceptor composed of only bulk silicon carbide targeted at the time of the etching process may be, for example, 0.02 μm / min or less.
The reason for this is that, as shown in Table 1, the etching rate of samples 4 and 5 is about 2 μm, and the target etching rate of the silicon carbide susceptor composed only of bulk silicon carbide is 0.02 μm / min or less. Thus, for example, an etching resistance of 100 times or more that of a susceptor coated with silicon carbide can be obtained. In other words, it becomes possible to use a susceptor that has been disabled by one use 100 times or more.

  The present invention can be applied to a cleaning method for a susceptor used in a film forming chamber of a silicon carbide film forming apparatus.

  DESCRIPTION OF SYMBOLS 10,55 ... Silicon carbide susceptor, 11,56 ... Susceptor main body, 11a, 56a, 251a ... Upper surface, 11b, 56b ... Lower surface, 12,252 ... Housing part, 12-1, 252-1 ... First recessed part, 12 -1a ... bottom surface, 12-2, 252-2 ... second recess, 20 ... silicon carbide substrate, 20a ... front surface, 20b ... back surface, 20A ... outer periphery, 21 ... silicon carbide film, 22 ... deposit, 30, DESCRIPTION OF SYMBOLS 60 ... Silicon carbide film-forming apparatus, 31, 61 ... Film-forming chamber, 31A, 67, 91A ... Reaction space, 33, 93 ... Stage, 35, 76 ... First heating part, 37, 68 ... First heat insulation member , 38 ... exhaust port, 39 ... rotating shaft, 41 ... rotation drive unit, 42, 71, 97 ... susceptor receiving member, 43 ... ceiling plate member, 44, 78 ... second heating unit, 45, 69 ... second Insulating members, 47, 74 ... third insulating members, 49 ... Gas gas outlet, 81 ... Raw material gas inlet, 82 ... Gas outlet, 90 ... Silicon carbide removing device, 91 ... Chamber, 95 ... Heater, 101 ... Fluorine-containing gas supply, 102 ... Oxygen-containing gas supply, DESCRIPTION OF SYMBOLS 104 ... Plasma generation part, 106 ... Vacuum pump, 107 ... Gas pipe, 109 ... Exhaust gas analysis part, 111 ... Control part, 121 ... Susceptor protection board, A ... Area, B ... Circumference, C, N ... Center, E, P ... Gap, S ... Surface direction

Claims (3)

A method of cleaning a susceptor that removes deposits made of silicon carbide deposited on a susceptor including a housing portion that houses a silicon carbide substrate on which a silicon carbide film is formed,
Preparing a silicon carbide susceptor composed only of bulk silicon carbide as the susceptor;
Removing the silicon carbide susceptor to which the deposit has adhered from a film forming chamber of a silicon carbide film forming apparatus;
Placing the silicon carbide susceptor to which the deposit is attached in a chamber of a silicon carbide removing device, and disposing a susceptor protection substrate for protecting the silicon carbide susceptor in the housing portion;
A first step of selectively removing silicon components contained in the deposit by supplying a plasma-containing fluorine-containing gas into the chamber, and supplying a plasma-ized oxygen-containing gas into the chamber doing, comprising a second step of selectively removing the carbon component contained in the deposit, seen including a an etching step of performing said second step and the first step alternately or simultaneously,
A method of cleaning a susceptor , wherein the susceptor protection substrate is disposed in the housing portion so that a surface of the susceptor protection substrate is flush with an upper surface of the susceptor. RCA cleaning the susceptor after the etching step;
Cleaning the susceptor with ultra pure water after the RCA cleaning;
After washing with the ultrapure water, and drying the susceptor,
The susceptor cleaning method according to claim 1, comprising: 3. The susceptor cleaning method according to claim 1, wherein an average surface roughness Ra of the silicon carbide susceptor from which the deposit is removed is 1 μm or less.

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