JP2021100030A - Substrate holder, substrate processing device, and substrate processing method - Google Patents

Abstract

To provide a substrate holder, a substrate processing device, and a substrate processing method that can stably hold a substrate by suppressing the film formation of silicon carbide on a susceptor, and can inexpensively perform stable film formation by epitaxial growth of silicon carbide for a long period of time by repeatedly using the susceptor with a longer life without removing the silicon carbide.SOLUTION: A substrate holder includes a susceptor having a mounting portion on which a substrate to be processed is placed and whose outer peripheral diameter is equal to or larger than the outer diameter of the substrate, and a wall-shaped peripheral edge portion surrounding the outer circumference, and a lid having an opening whose diameter is smaller than the outer diameter of the substrate and placed on the peripheral edge portion.SELECTED DRAWING: Figure 1

Description

The present invention relates to a substrate holder, a substrate processing apparatus, and a substrate processing method, for example, a substrate processing apparatus capable of forming an epitaxial film of silicon carbide (SiC), a substrate holder that can be provided in the substrate processing apparatus, and a substrate holder. The present invention relates to a substrate processing method using the substrate holder.

Silicon carbide (SiC) is a compound semiconductor material composed of silicon (Si) and carbon. SiC is not only excellent in dielectric breakdown electric field strength 10 times that of Si and bandgap 3 times that of Si, but also because it is possible to control p-type and n-type required for device fabrication in a wide range. , Is expected as a material for power devices that exceeds the limit of Si.

Further, since silicon carbide can obtain a high withstand voltage even with a thinner thickness, it is characterized in that a semiconductor having a small ON resistance and a low loss can be obtained by making it thin.

In a film forming apparatus used in an epitaxial growth technique for silicon carbide, such as an epitaxial growth apparatus, for example, a wafer is placed inside a film forming chamber held at normal pressure or reduced pressure. Then, while heating this wafer, a gas as a raw material for film formation (hereinafter, may be simply referred to as “raw material gas”) is supplied to the film forming chamber. Then, a thermal decomposition reaction and a hydrogen reduction reaction of the raw material gas occur on the surface of the wafer, and an epitaxial film is formed on the wafer (for example, Patent Document 1).

In order to stably produce an epitaxial wafer with a high yield, it is necessary to bring new raw material gases into contact with the surface of the uniformly heated wafer one after another to improve the rate of vapor phase growth. Therefore, epitaxial growth is performed while rotating the wafer at high speed.

Japanese Unexamined Patent Publication No. 2018-046149

In the conventional SiC epitaxial growth apparatus, not only the SiC film is formed on the wafer, but also the SiC film is deposited on the front surface of the susceptor holding the wafer. The susceptor with the SiC film deposited on the front surface may be deformed due to the difference in the thermal expansion rate between the front surface portion and the back surface portion on which the SiC film is not deposited. When this deformation occurs, the wafer cannot be stably held and cannot rotate at high speed.

Further, by repeating the SiC epitaxial film forming process in the apparatus, SiC continues to be formed and deposited on the surface of the susceptor, which may cause protrusions or steps on the surface of the susceptor or the side wall of the inner diameter portion. Due to the generated steps and protrusions, the susceptor cannot stably hold the wafer set on the susceptor, which leads to the wafer being detached from the susceptor due to the rotation of the susceptor during film formation. If the wafer is removed from the susceptor, the wafer may be damaged or the damaged wafer may remain in the film forming furnace, which also contributes to particles during film formation.

More specifically, the epitaxial film formation process of SiC will be described first. First, the wafer to be filmed is installed on the susceptor, and the susceptor on which the wafer is installed is set on the rotating portion in the growing furnace of the epitaxial growth apparatus. Then, at the time of film formation, the wafer and the susceptor set on the rotating portion are rotated, and the raw material gas is sprayed onto the wafer to grow epitaxially, and the film formation proceeds.

When the film forming process is repeated, SiC is deposited in addition to the wafer due to the influence of the reaction of the raw material gas. In particular, there is a large amount of SiC deposited on the surface of the susceptor, and as the deposition progresses, the SiC deposited in the plane of the mounting portion of the susceptor on which the wafer is placed becomes a step, making it difficult to stably hold the wafer. May become. At the time of film formation by epitaxial growth, it is necessary to spray the raw material gas after rotating the wafer in order to perform stable film formation. Therefore, if the wafer becomes an unstable holding state due to the influence of the step generated on the mounting portion of the susceptor, the wafer may pop out from the susceptor by rotating the susceptor, and as a result of the popping out, the wafer may be damaged. It may end up.

Therefore, it is ideal to suppress the adhesion of SiC to the susceptor, but it is structurally difficult to control the supply of the raw material gas only to the wafer because the wafer is held by the susceptor. Although there is a method of suppressing the adhesion of SiC by changing the temperature of only the susceptor, it is difficult to suppress the influence of heat conduction on the susceptor, and in reality, it is difficult to prevent the film formation on the susceptor.

Therefore, it is preferable to periodically remove the SiC adhering to the susceptor so that the wafer can be stably held, but the SiC is a very hard substance and the SiC adhering to the susceptor cannot be easily removed. .. Further, even if SiC is removed, a great deal of cost and time will be required. Therefore, it is not preferable to increase the frequency of removing SiC adhering to the susceptor.

In view of such circumstances, the present invention can keep the substrate stable by suppressing the film formation of silicon carbide on the susceptor, and the susceptor can be extended without removing the silicon carbide. It is an object of the present invention to provide a substrate holder, a substrate processing apparatus, and a substrate processing method capable of stably forming a film by epitaxial growth of silicon carbide for a long period of time by extending the life of the silicon carbide. ..

In order to solve the above problems, the substrate holder of the present invention mounts a substrate to be processed, and has a mounting portion whose outer diameter is equal to or larger than the outer diameter of the substrate, and a wall-shaped peripheral edge surrounding the outer circumference. A susceptor having a portion, and a lid having an opening having a diameter smaller than the outer diameter of the substrate and being placed on the peripheral portion are provided.

The thickness of the lid may be 1 mm or less.

The substrate and the lid may be in contact with each other, or the gap between the substrate and the lid may be within 0.5 mm.

The difference between the outer diameter of the substrate and the diameter of the opening of the lid may be 0.5 mm or less.

A fixing means for fixing the lid to the susceptor in a state of being placed on the peripheral portion may be provided.

Further, in order to solve the above problems, the substrate processing apparatus of the present invention includes the above-mentioned substrate holder of the present invention.

The substrate processing apparatus may be a film forming apparatus for forming a film on the substrate by a chemical vapor deposition method.

Further, in order to solve the above problems, the substrate processing method of the present invention comprises a substrate holding step of holding the substrate on the substrate holder of the present invention described above, and after the substrate holding step, the substrate is rotated while the susceptor is rotated. Including a processing step of processing.

The processing step may be a film forming step of forming a film on the substrate.

According to the present invention, by suppressing the film formation of silicon carbide on the susceptor, the substrate can be stably held, and the susceptor is repeatedly extended in life without removing the silicon carbide. By being able to use it, it is possible to provide a substrate holder, a substrate processing apparatus, and a substrate processing method capable of stably forming a film by epitaxial growth of silicon carbide at low cost and for a long period of time.

It is the schematic which shows the side cross section of the substrate holding body 100 which holds a substrate 10. It is the schematic of the susceptor 110. It is a perspective view of the susceptor 210. It is the schematic of the lid 120. It is a perspective view of the lid 220. It is the schematic which shows the side cross section of the epitaxial growth apparatus 1000. It is the schematic which shows the side cross section of the susceptor 110 on which the wafer 10 is placed. FIG. 5 is a schematic view showing a side cross section of a state in which a substrate 10 is placed on a susceptor 110 to which silicon carbide 300 is attached by repeatedly performing a film forming process by the epitaxial growth apparatus 1000. It is a graph which shows the number of times of protrusion of the substrate 10 per cumulative film formation amount. It is a graph which shows the influence which the difference in the thickness of a lid 112 has on the film thickness.

Hereinafter, one embodiment of the substrate holder, the substrate processing apparatus, and the substrate processing method of the present invention will be described. However, the present invention is not limited to these one embodiments.

[Board holder]
Examples of the substrate holder of the present invention include a substrate holder 100 that holds the substrate 10 shown in FIG. 1, and includes a susceptor 110 and a lid 120.

<Suceptor 110>
2A and 2B are schematic views of the susceptor 110, FIG. 2A is a side sectional view of the susceptor 110, and FIG. 2B is a plan view of the susceptor 110. The susceptor 110 has a mounting portion 112 on which the substrate 10 to be processed is mounted and the diameter of the outer peripheral 111 is equal to or larger than the outer diameter of the substrate 10, and a wall-shaped peripheral peripheral portion 115 surrounding the outer peripheral 111. The mounting portion 112 has a circular shape that is a concave flat surface recessed from the peripheral edge portion 115. Further, the peripheral edge portion 115 includes a wall 116 extending vertically from the outer peripheral portion 111 of the mounting portion 112, and the upper portion 117 has a flat shape having a predetermined width.

When the substrate 10 is mounted on the mounting portion 112 and the susceptor 110 is rotated, the peripheral edge portion 115 on the side surface of the substrate 10 can play a role of preventing the substrate 10 from shifting or popping out.

As the susceptor of the present invention, in addition to the susceptor 110, a susceptor 210 having a plurality of mounting portions 212 shown in FIG. 3 can be mentioned, and a plurality of substrates 10 can be mounted. Like the susceptor 110, the susceptor 210 has a wall-shaped peripheral edge portion 215 having a diameter of the outer circumference 211 equal to or larger than the outer diameter of the substrate 10 and surrounding the outer circumference 211. The mounting portion 212 has a circular shape which is a concave flat surface recessed from the peripheral portion 215. Further, the peripheral edge portion 215 is provided with a wall 216 extending vertically from the outer peripheral portion 211 of the mounting portion 212, and the upper portion 217 is a flat surface having a predetermined width.

As the susceptors 110 and 210, for example, when used in a SiC epitaxial growth apparatus, carbon susceptors can be used. Further, in the case of other uses, a susceptor made of a material suitable for each use can be used.

The substrate 10 to be processed includes, for example, a disk-shaped wafer, but is not particularly limited, and may be a plate on which parts or the like for realizing some function can be arranged.

<Lid 120>
4A and 4B are schematic views of the lid 120, FIG. 4A is a side sectional view of the lid 120, and FIG. 4B is a plan view of the lid 120. The lid 120 has an opening 121 whose diameter is smaller than the outer diameter of the substrate 10, and has a ring shape to be placed on the peripheral edge 115 of the susceptor 110. The outer diameter of the lid 120 may be substantially the same as the outer diameter of the susceptor 110.

As shown in FIG. 1, when the substrate 10 is mounted on the mounting portion 112 and the lid 120 is mounted on the peripheral edge portion 115 of the susceptor 110 and the substrate holder 100 is rotated, the side surface of the substrate 10 is mounted. The peripheral edge portion 115 at the above can play a role of preventing the substrate 10 from slipping or popping out. Further, since the opening 121 of the lid 120 has a diameter smaller than the outer diameter of the substrate 10, it is possible to prevent the substrate 10 from popping out due to the rotation of the substrate holder 100, and the opening 120 can be opened from the outside of the substrate holder 100. A predetermined process can be applied to the substrate 10 through the substrate 10.

As the lid of the present invention, in addition to the lid 120, a lid 220 having a plurality of openings 221 shown in FIG. 5 can be mentioned, and the plurality of substrates 10 can be prevented from popping out. Like the lid 120, the lid 220 has a plurality of openings 221 having a diameter smaller than the outer diameter of the substrate 10, and can be placed on the peripheral edge portion 215 of the susceptor 210. The outer diameter of the lid 220 may be substantially the same as the outer diameter of the susceptor 210.

As the lids 120 and 220, for example, when used in a SiC epitaxial growth apparatus, carbon lids can be used. Further, in the case of other uses, a lid made of a material suitable for each use can be used.

<Fixing means>
The substrate holder 100 can be provided with fixing means 130 for fixing the lid 120 to the susceptor 110 in a state of being placed on the peripheral edge portion 115 (FIG. 1). By fixing the lid 120 to the susceptor 110 by the fixing means 130, it is possible to more reliably prevent the substrate 10 from popping out when the substrate holder 100 is rotated. When the lid 220 is fixed to the susceptor 210, the fixing means can be used in the same manner.

The fixing means is not particularly limited as long as the lid can be fixed to the susceptor. For example, like the fixing means 130 shown in FIG. 1, the shape may be a nail, a screw, a nail, or the lid and the susceptor may be fixed by a fastening member composed of a bolt and a nut, a clip, a clamp, or the like. ..

As the fixing means, for example, when used in a SiC epitaxial growth device, a carbon fixing means can be used. Further, in the case of other uses, a fixing means of a material suitable for each use can be used.

(Example of using the substrate holder 100)
Hereinafter, an example of using the substrate holder 100 will be described. FIG. 6 is a schematic view showing a side cross section of an epitaxial growth apparatus 1000 for forming an epitaxial film of silicon carbide on a substrate 10 by a chemical vapor deposition method. The epitaxial growth apparatus 1000 includes a box-shaped heat insulating material 1200 for forming the film forming chamber 1100, a raw material gas introduction port 1300 for introducing the raw material gas into the film forming chamber 110, and a susceptor 110 on which the substrate 10 is placed on the mounting portion 112. At least includes a rotating stage 1400 on which the gas is placed and rotated.

Explaining the procedure for growing an epitaxial film on the substrate 10 using the epitaxial growth apparatus 1000, for example, the substrate 10 is placed on the mounting portion 112 of the susceptor 110 in the film forming chamber 1100 of the epitaxial growth apparatus 1000. Alternatively, the susceptor 110 on which the substrate 10 is placed is set in the film forming chamber 1100 of the epitaxial growth apparatus 1000. After that, the temperature inside the film forming chamber 1100 is raised to a designated temperature. After the temperature rises, the susceptor 110 on which the substrate 10 is placed is rotated by the rotation stage 1400 as shown by the arrow A, and the raw material is introduced into the film forming chamber 1100 from the raw material gas introduction port 1300 in the direction indicated by the arrow B. A film can be formed by blowing the gas onto the substrate 10.

FIG. 7 is a schematic view showing a side cross section of the susceptor 110 on which the substrate 10 is placed. When the epitaxial film is grown on the substrate 10, the raw material gas is blown from the upper part of the substrate 10 to the front surface 11 of the substrate 10. As a result, the film formation proceeds due to the reaction on the surface of the substrate 10, but the raw material gas is affected by the centrifugal force due to the rotation of the substrate 10 and spreads over the entire surface 11 of the substrate 10. Can be done. In the flow of the raw material gas from the center of the front surface 11 of the substrate 10 to the end portion 12 of the substrate 10, the raw material gas that has reached the end portion 12 reaches the wall 116 of the susceptor 110. The gas flow of the raw material is blocked by the wall 116, so that convection occurs near the end portion 12 of the substrate 10, and this convection causes variations in the film thickness distribution of the epitaxial film in the front surface 11 of the substrate 10. It may contribute.

Therefore, in order to prevent this convection, it is preferable that the front surface 11 of the substrate 10 and the upper portion 117 of the susceptor 110 are on the same plane without a step. However, the height of the peripheral edge 115 is set so that the upper portion 117 of the susceptor 110 is 0.5 to 0.6 mm higher than the front surface 11 of the substrate 10 so that the substrate 10 can be prevented from popping out due to the rotation of the susceptor 110. Can be set.

FIG. 8 shows a schematic side cross section of a state in which the substrate 10 is placed on the susceptor 110 to which the silicon carbide 300 is attached by repeatedly performing the film forming process by the epitaxial growth apparatus 1000. By repeating the film forming process, the silicon carbide 300 adheres to and accumulates on the mounting portion 112 and the wall 116 of the susceptor 110, so that the mounting portion 112 and the wall 116 which are important for holding the substrate 10 are deposited. In this case, protrusions and steps are generated by the silicon carbide 300. When such protrusions or steps occur, even if the substrate 10 is mounted on the mounting portion 112, the substrate 10 is placed in an unstable state due to a gap between the mounting portion 112 and the substrate 10 or the like. Will be done. If the susceptor 110 is rotated in the film forming chamber 1100 in this state, the susceptor 110 may not be able to hold the substrate 10 firmly, and the substrate 10 may fly from the susceptor 110. In this case, the substrate 10 may be damaged due to a collision with the inner wall of the film forming chamber 110 or the like. Further, since the film formation cannot be controlled on the flying substrate 10, a desired epitaxial film cannot be grown. As described above, it is not preferable to increase the frequency of maintenance for removing the silicon carbide 300 because the removal of the silicon carbide 300 adhering to the susceptor 110 requires a great deal of cost and time.

However, the above problem can be solved by using the substrate holder 100. That is, in the case of the substrate holder 100 having the lid 120 as well as the susceptor 110, the presence of the lid 120 prevents the raw material gas from adhering to the mounting portion 112 and the wall 116 via the side surface of the substrate 10. Can be prevented. Therefore, even if the substrate holder 100 is used repeatedly, the substrate 10 can be stably and firmly held, and the substrate 10 can be prevented from flying. Therefore, all the substrates 10 installed in the epitaxial growth apparatus 1000 can be prevented. By forming an epitaxial film in the above, the yield can be increased.

Further, since silicon carbide does not easily adhere to the mounting portion 112 and the wall 116, the susceptor 110 can be used repeatedly with a longer life. Further, the cost for film formation can be suppressed by reducing the number of maintenances for removing the silicon carbide 300 or eliminating the need for maintenance.

Therefore, stable film formation by epitaxial growth of silicon carbide can be performed inexpensively and for a long period of time.

The thickness of the lid 120 and the lid 220 is preferably 1 mm or less. By doing so, it is possible to suppress abnormal film formation without obstructing the natural flow of the raw material gas sprayed onto the substrate 10, and it is stable by suppressing the bias of film formation on the film formation target surface of the substrate 10. It is possible to maintain a realistic film formation. Further, the thickness of the lid 120 and the lid 220 is preferably as uniform as possible so as not to obstruct the flow of the raw material gas. For example, the thickness error can be set within ± 0.1 mm of the average thickness.

If the thickness of the lid 120 or the lid 220 is thicker than 1 mm, the natural flow of the raw material gas may be hindered, and as a result, the film formation on the film formation target surface of the substrate 10 is biased, resulting in stable formation. It may be difficult to maintain the membrane.

When the substrate holder 100 holds the substrate 10, it is preferable that the substrate 10 and the lid 120 are in contact with each other as shown in FIG. 1, or the gap between the substrate 10 and the lid 120 is within 0.5 mm. By doing so, it is possible to suppress abnormal film formation without obstructing the natural flow of the raw material gas sprayed onto the substrate 10, and it is stable by suppressing the bias of film formation on the film formation target surface of the substrate 10. It is possible to maintain a realistic film formation.

Further, since the gap between the substrate 10 and the lid 120 is within 0.5 mm, it is possible to prevent or suppress the invasion of the raw material gas into the side surface of the mounted substrate 10 during the film forming process. Adhesion and accumulation of silicon carbide 300 on 112 and wall 116 can be prevented or suppressed.

Similarly, in the case of the substrate 10 and the lid 220, it is preferable that the substrate 10 and the lid 220 are in contact with each other, or the gap between the substrate 10 and the lid 220 is within 0.5 mm.

If the gap between the substrate 10 and the lid 120 or the lid 220 is larger than 0.5 mm, the natural flow of the raw material gas may be obstructed, and as a result, the film formation is biased on the film formation target surface of the substrate 10. As a result, it may be difficult to maintain a stable film formation. In addition, the raw material gas may invade the side surface of the substrate 10 placed during the film forming process, which may cause the silicon carbide 300 to adhere to or accumulate on the mounting portion 112, the wall 116, or the like.

Further, in addition to the opening 121 of the lid 120 and the opening 221 of the lid 220 having a diameter smaller than the outer diameter of the substrate 10, the outer diameter of the substrate 10 and the opening 121 of the lid 120 or the opening of the lid 220 The difference from the diameter of 221 is preferably within 0.5 mm. Since this difference is within 0.5 mm, even if the silicon carbide 300 adheres to the mounting portion 112, the wall 116, or the like to cause a step or the like, the substrate 10 due to the rotation of the susceptor 110 or the susceptor 210 Can be prevented from popping out. Further, since the processing target area of the substrate 10 is not excessively narrowed, for example, when an epitaxial film is formed on the substrate 10, the formed area is not excessively narrowed, and there is no effect on the manufacturing efficiency of the epitaxial substrate. ..

If the above difference is larger than 0.5 mm, the processing target area of the substrate 10 may be narrowed. For example, when an epitaxial film is formed on the substrate 10, the film formation area is narrowed, so that the epitaxial film is epitaxially formed. There is a risk that the manufacturing efficiency of the substrate will decrease.

Further, in order to obtain the effect of preventing the silicon carbide 300 from adhering to the mounting portions 112, 212 and the walls 116 and 216 due to the intrusion of the raw material gas, the outer diameter of the substrate 10 and the opening of the lid 120 are obtained. The difference from the diameter of the opening 221 of the portion 121 or the lid 220 is more preferably 0.2 mm to 0.5 mm.

In the above, an example of using the substrate holder 100 in the silicon carbide epitaxial growth apparatus 1000 has been mainly mentioned, but other uses can be considered as the substrate holder of the present invention. The substrate holder of the present invention is useful when the substrate is rotated for processing. For example, a film forming apparatus for rotating a substrate to form a polycrystalline film of silicon carbide, or a surface to be coated with a substrate is designated. The substrate holder 100 can also be used for a spin coater for spin-coating the treatment liquid of the above, a substrate cleaning device having a mechanism for removing the cleaning liquid by rotating the substrate after cleaning the surface to be cleaned with the cleaning liquid, and the like.

[Board processing equipment]
Next, an example of the substrate processing apparatus of the present invention will be described. The substrate processing apparatus of the present invention includes the substrate holder of the present invention described above.

The substrate processing apparatus is not particularly limited as long as it includes a substrate holder. For example, it may be a film forming apparatus for forming a film on the substrate by a chemical vapor deposition method. Specifically, the epitaxial growth apparatus 1000 shown in FIG. 6 as a film forming apparatus is a substrate made of silicon carbide. An epitaxial film can be formed on the surface.

Further, since the substrate holder of the present invention is useful when the substrate is rotated for processing, the substrate processing apparatus of the present invention is a spin coater that spin-coats a predetermined treatment liquid on the surface to be coated with the substrate. There may be. As yet another aspect, the substrate cleaning apparatus may have a mechanism for removing the cleaning liquid by rotating the substrate after cleaning the surface to be cleaned of the substrate with the cleaning liquid.

[Board processing method]
Next, an example of the substrate processing method of the present invention will be described. The substrate processing method of the present invention includes a substrate holding step of holding the substrate on the substrate holder of the present invention described above, and a processing step of processing the substrate while rotating the susceptor after the substrate holding step.

The treatment step may be a film forming step of forming a film on the substrate. For example, as a substrate processing method of the present invention, a substrate processing method for growing an epitaxial film on a substrate 10 using the epitaxial growth apparatus 1000 will be described as an example.

<Board holding process>
As a substrate holding step, for example, in the film forming chamber 1100 of the epitaxial growth apparatus 1000, the substrate 10 is placed on the mounting portion 112 of the susceptor 110, the lid 112 is covered, and the susceptor 110 is appropriately used by the fixing means 130. Examples thereof include a step of fixing the lid 112. Alternatively, a step of mounting the substrate 10 on the mounting portion 112 of the susceptor 110 outside the film forming chamber 1100, covering the substrate 112, and appropriately fixing the susceptor 110 and the lid 112 with the fixing means 130 can be mentioned. .. In this case, the substrate holder 100 is set in the film forming chamber 1100 of the epitaxial growth apparatus 1000 after the substrate holding step.

<Processing process>
As a treatment step, for example, in the case of a film forming step, the temperature inside the film forming chamber 1100 is raised to a designated temperature after the substrate holding step. After the temperature rises, the substrate holder 100 on which the substrate 10 is placed is rotated by the rotation stage 1400 as shown by the arrow A, and is introduced into the film forming chamber 1100 from the raw material gas introduction port 1300 in the direction indicated by the arrow B. The film formation process can be performed by spraying the raw material gas on the substrate 10.

The treatment step is not limited to the film forming step, and for example, when a spin coater is used, it may be a step of spin-coating a predetermined treatment liquid on the surface to be coated of the substrate 10. As yet another aspect, when a substrate cleaning device is used, the step may be a step of cleaning the surface to be cleaned of the substrate 10 with the cleaning liquid and then rotating the substrate to remove the cleaning liquid.

(Other processes)
The substrate processing method of the present invention may include a further step in addition to the substrate holding step and the processing step. For example, a curing step for cleaning the substrate 10 to be treated, a determination step for determining whether or not the substrate has been sufficiently treated after the treatment step, and the like can be mentioned.

The present invention will be described in detail with reference to the examples shown below. However, the present invention is not limited to these examples.

[Details of evaluation]
When the epitaxial growth apparatus 1000 shown in FIG. 6 is used to hold the substrate 10 on the substrate holder 100 provided with the susceptor 110 and the lid 112 to perform the film formation treatment of the epitaxial growth film, and when the lid 112 is not used as in the conventional case. The presence or absence of protrusion of the substrate 10 and the influence on the film thickness of the epitaxial growth film were evaluated in the case where the substrate 10 was placed on the susceptor 110 and the epitaxial growth film was formed.

In the evaluation, the only difference is whether the substrate holder 100 or the susceptor 110 is used to hold the substrate 10, the composition and mixing ratio of the substrate 10, the raw material gas, the flow rate and spraying time of the raw material gas, and the substrate. The film formation was repeated under the same film formation conditions such as the rotation speed of 10.

<Evaluation of protrusion of substrate 10>
The film formation process on the substrate 10 was repeated by the epitaxial growth apparatus 1000, and the number of times the substrate 10 was ejected per the cumulative film formation amount was evaluated.

As the substrate 10, a silicon carbide single crystal wafer having a diameter of 152.4 mm (6 inches) and a thickness of 0.5 mm was used. The susceptor 110 is made of carbon and has a diameter of 163 mm, a diameter of the outer circumference 111 of the mounting portion 112 of 153 mm, a width of the peripheral portion 115 of 5 mm, a thickness of the mounting portion 112 of 2 mm, and a height of the wall 116 of the substrate 10. It was set to 0.5 mm according to the above. The lid 120 is made of carbon and has a uniform thickness of 0.5 mm, the diameter of the opening is 152.1 mm, which is 0.3 mm smaller than the diameter of the substrate 10, and the diameter is 163 mm, which is the same as that of the susceptor 110. The width of the ring was 5.45 mm. Further, as the fixing means 130, a carbon low-head screw with the protrusion of the screw head suppressed was used, and the susceptor 110 and the lid 120 were fixed by screwing evenly at four portions.

Further, in the film forming process, the substrate holder 100 and the susceptor 110 were not replaced and were repeatedly used from the beginning until the test was completed.

The results are shown in FIG. In FIG. 9, the horizontal axis is the cumulative amount of film formed on which the epitaxial growth film is formed, the white graph shows the case where the substrate holder 100 is used, and the black graph shows the case where the susceptor 110 is used. In addition, the item "100 μm" indicates the number of times the substrate 10 has popped out during the period from the first film formation process to the cumulative film formation amount of 100 μm. The item "300 μm" indicates the number of times the substrate 10 has popped out when the cumulative film formation amount is between 100 μm and 300 μm. The same applies to the items of 500 μm to 1500 μm, and the film formation treatment was performed 10 times for each item.

From the results of FIG. 9, when the susceptor 110 is used without using the lid 120, the substrate 10 is not projected up to the item where the cumulative film formation amount is 300 μm, but the cumulative film formation amount exceeds 500 μm. It was found that the frequency of popping out of the substrate 10 rapidly increased. When the state of the susceptor 110 from which the substrate 10 protruded was confirmed each time after the film forming process, silicon carbide gradually adhered to the surface and the wall 116 of the mounting portion 112, and when the cumulative film forming amount exceeded 500 μm. It was confirmed that the adhered silicon carbide had grown into steps and protrusions, and it was clear that these steps and protrusions caused the substrate 10 to pop out.

On the other hand, when the substrate holder 100 was used, the substrate 10 did not pop out even once from the start of the film forming process to the state where the cumulative film forming amount was 1500 μm. In particular, due to the presence of the lid 120, silicon carbide hardly adhered to the mounting portion 112 and the wall 116 of the susceptor 110. Further, even when silicon carbide adheres to the mounting portion 112 or the wall 116 to cause a step or protrusion at the final stage of the repeated film forming process, the lid 120 prevents the substrate 10 from popping out. I was able to.

<Evaluation of the effect of the thickness of the lid 112 on the film thickness>
Here, lids 120 having different thicknesses from 0.5 mm to 2.0 mm were prepared, and the epitaxial growth film was formed once as the substrate holder 100, and the epitaxial growth film was formed on the substrate 10. Then, the film thickness of the obtained epitaxial growth film was measured and compared with the average value of the film thickness of the epitaxial growth film when the susceptor 110 was used without using the lid 120, and the bias of the film thickness was evaluated.

The results are shown in FIG. In FIG. 10, the thickness of the lid 120 is taken as the horizontal axis, and the average value of the film thickness of the epitaxial growth film when the susceptor 110 is used without using the lid 120 is shown as 100% at 0 mm. Then, comparing the average value of this film thickness with the film thickness of the thickest portion of the epitaxial growth film formed by using the lid 120, the case where the film thickness is 1.2 times thicker is 120. %, 1.4 times thicker was plotted as 140%.

As a result, when the thickness of the lid 120 was 1 mm or less, the thickness of the formed epitaxial growth film was almost uniform, and a film having the same film thickness as when the lid 120 was not used could be obtained. This indicates that if the thickness of the lid 120 is 1 mm or less, the lid 120 does not obstruct the natural flow of the raw material gas and is almost the same as the state without the lid 120.

When the thickness of the lid 120 exceeded 1 mm, the thickness of the epitaxial growth film was biased, and there was a tendency for a thick film to be formed. It was expected that this was due to the lid 120 obstructing the natural flow of the source gas.

However, since the film thickness up to about 120% is within an acceptable range, it was suggested that if the thickness of the lid 120 is up to 1.5 mm, there is no problem even if it is used for forming an epitaxial growth film. ..

[Summary]
As described above, according to the present invention, by suppressing the film formation of silicon carbide on the susceptor, the substrate can be stably held and the susceptor can be extended without removing the silicon carbide. Since the life is extended and the silicon carbide can be used repeatedly, stable film formation by epitaxial growth of silicon carbide can be performed inexpensively and for a long period of time.

10 Board 11 Front surface 12 End 100 Board holder 110 Suceptor 111 Perimeter 112 Mounting part 115 Perimeter 116 Wall 117 Top 120 Lid 121 Opening 130 Fixing means 210 Sucepter 211 Perimeter 212 Mounting 215 Perimeter 216 Wall 217 Upper part 220 Lid 221 Opening 1000 Epitaxial growth device 1100 Formation chamber 1200 Insulation material 1300 Raw material gas inlet 1400 Rotating stage A Arrow B Arrow

Claims (9)

A susceptor having a mounting portion on which a substrate to be processed is placed and whose outer peripheral diameter is equal to or larger than the outer diameter of the substrate, and a wall-shaped peripheral peripheral portion surrounding the outer circumference.
A substrate holder having an opening having a diameter smaller than the outer diameter of the substrate and having a lid to be placed on the peripheral portion. The substrate holder according to claim 1, wherein the lid has a thickness of 1 mm or less. The substrate holder according to claim 1 or 2, wherein the substrate and the lid are in contact with each other, or the gap between the substrate and the lid is within 0.5 mm. The substrate holder according to any one of claims 1 to 3, wherein the difference between the outer diameter of the substrate and the diameter of the opening of the lid is within 0.5 mm. The substrate holder according to any one of claims 1 to 4, further comprising a fixing means for fixing the lid to the susceptor while the lid is placed on the peripheral edge portion. A substrate processing apparatus comprising the substrate holder according to any one of claims 1 to 5. The substrate processing apparatus according to claim 6, wherein the substrate processing apparatus is a film forming apparatus for forming a film on the substrate by a chemical vapor deposition method. A substrate holding step of holding the substrate on the substrate holder according to any one of claims 1 to 5.
After the substrate holding step, a processing step of processing the substrate while rotating the susceptor,
Substrate processing methods, including. The substrate processing method according to claim 8, wherein the processing step is a film forming step of forming a film on the substrate.

Images