JP2012028385A - Semiconductor manufacturing apparatus and cleaning method of susceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor manufacturing apparatus capable of removing a film deposited on a susceptor in an SiC epitaxial growth process, and to provide a cleaning method of the susceptor capable of removing the SiC film deposited in the SiC epitaxial growth process.SOLUTION: A semiconductor manufacturing apparatus 1 includes: a film formation chamber 2 forming an SiC epitaxial film on a wafer W located on a susceptor S; and a cleaning chamber 5 communicating with the film formation chamber 2 through a conveyance chamber 4 having a robot 17 for transportation through which the susceptor S is transported, and removing an SiC film deposited on the susceptor S. The cleaning chamber 5 includes: a heater heating the susceptor S at a temperature of 400°C or higher; and etching gas supply means supplying etching gas from above the susceptor S to remove the SiC film.

Description

  The present invention relates to a semiconductor manufacturing apparatus and a susceptor cleaning method.

  Conventionally, an epitaxial growth technique has been used for manufacturing a semiconductor element that requires a relatively thick crystal film, such as a power device such as an IGBT (Insulated Gate Bipolar Transistor).

  In the vapor phase growth method used for the epitaxial growth technique, a wafer is placed inside a film formation chamber maintained at normal pressure or reduced pressure, and a reactive gas is supplied into the film formation chamber while heating the wafer. Then, a thermal decomposition reaction and a hydrogen reduction reaction of the reaction gas occur on the surface of the wafer, and an epitaxial film is formed on the wafer.

  In order to manufacture a thick epitaxial film with a high yield, it is necessary to improve the film formation rate by bringing new reaction gases into contact with the uniformly heated wafer surface one after another. Therefore, in a conventional film forming apparatus, for example, epitaxial growth is performed while rotating a wafer at a high speed (see, for example, Patent Document 1).

  When vapor phase growth is performed in the film forming chamber, in addition to the surface of the wafer, the susceptor that supports the wafer, the inner wall of the film forming chamber, the piping for exhausting the gas in the film forming chamber, and the like are caused by the reaction gas. A film adheres. When this film is peeled off, it becomes dust and causes a defect in the epitaxial film formed on the wafer. Therefore, it is necessary to remove the attached film.

  Patent Document 2 discloses an apparatus including an etching chamber for removing a coating film formed on a susceptor when forming an Si (silicon) epitaxial film.

JP 2008-108983 A JP 2007-73628 A

  In recent years, SiC (silicon carbide) epitaxial growth technology has attracted attention. SiC is characterized by an energy gap that is two to three times larger than that of conventional semiconductor materials such as Si (silicon) and GaAs (gallium arsenide), and a dielectric breakdown electric field that is about one digit larger. For this reason, it is a semiconductor material expected to be used for high breakdown voltage power semiconductor devices.

However, the film adhering to the susceptor or the like when forming SiC cannot be removed by etching at room temperature using ClF ₃ gas. The present invention has been made in view of such problems. That is, an object of the present invention is to provide a semiconductor manufacturing apparatus capable of removing a film attached to a susceptor during a SiC epitaxial growth process and improving a manufacturing yield. Another object of the present invention is to provide a susceptor cleaning method capable of removing a SiC film deposited in a SiC epitaxial growth process.

  Other objects and advantages of the present invention will become apparent from the following description.

A first aspect of the present invention is a film formation chamber for forming a SiC epitaxial film on a wafer placed on a susceptor;
A cleaning chamber connected to the film forming chamber via a transfer chamber having a transfer means for transferring the susceptor, and removing the SiC film adhering to the susceptor;
The cleaning chamber has heating means for heating the susceptor at a temperature of 400 ° C. or higher,
The present invention relates to a semiconductor manufacturing apparatus comprising etching gas supply means for supplying an etching gas from above a susceptor to remove the SiC film.

  It is preferable that the 1st aspect of this invention has a rotation means to rotate a susceptor at 300 rpm-900 rpm.

A second aspect of the present invention is a susceptor cleaning method used in a SiC epitaxial growth process,
While the susceptor is heated at a temperature of 400 ° C. or higher, ClF ₃ gas is supplied from above the susceptor to remove the SiC film adhering to the susceptor.

In the second aspect of the present invention, it is preferable that the SiC film attached to the susceptor is removed by heating while rotating the susceptor and supplying ClF ₃ gas from above the susceptor.

  In the second aspect of the present invention, the temperature of the susceptor is preferably 600 ° C. or lower.

According to the first aspect of the present invention, the semiconductor manufacturing apparatus includes the cleaning chamber that removes the SiC film attached to the susceptor, so that the film forming process is not interrupted by the cleaning process. In addition, since this cleaning chamber has a heating means for heating the susceptor at a temperature of 400 ° C. or higher and an etching gas supply means for supplying an etching gas for the SiC film from above the susceptor, the SiC film attached to the susceptor is efficiently used. It can be etched away well.
The semiconductor manufacturing apparatus according to the present invention is a so-called vertical epitaxial growth apparatus in which a gas necessary for film formation is supplied from the upper surface of a wafer placed on a susceptor and a heater is provided on the back side of the susceptor. It is desirable to be applied.

According to the second aspect of the present invention, since the ClF ₃ gas is supplied from above the susceptor while heating the susceptor at a temperature of 400 ° C. or higher, the SiC film deposited in the SiC epitaxial growth process can be efficiently removed. it can.

It is a typical section top view of the semiconductor manufacturing device in this embodiment. It is an example of the typical sectional view of the cleaning room in this embodiment. It is an example of sectional drawing of the state in which the wafer was mounted in the susceptor, and a corresponding top view.

  FIG. 1 is a schematic cross-sectional plan view of a semiconductor manufacturing apparatus according to the present embodiment.

  As shown in FIG. 1, the semiconductor manufacturing apparatus 1 includes a film formation chamber 2 for forming a SiC film on the surface of a wafer W placed on a susceptor S, and a film formation chamber 2 via a first opening / closing part 3. And a cleaning chamber 5 that cleans the susceptor S that has been taken out of the film forming chamber 2 and then passed through the transfer chamber 4 through the second opening / closing portion 6.

  The film forming chamber 2 is provided with an introduction port 18 and an exhaust port 19. The introduction port 18 is connected to a cylinder containing a reaction gas or a cylinder containing a dilution gas through a pipe (not shown), and an appropriate amount of these gases is supplied as necessary. Further, the exhaust port 19 is connected to a vacuum pump (not shown) through a pipe (not shown) so that the gas in the film forming chamber 2 is discharged from here.

  In the film forming chamber 2, a SiC epitaxial film is formed on the wafer W. For this reason, the film forming chamber 2 is provided with a heating mechanism (not shown) using a heater and a rotating mechanism (not shown), and the wafer W is placed on the susceptor S to heat the wafer W. Then, the wafer W is rotated through the susceptor S. In this state, the SiC epitaxial film is formed on the surface of the wafer W by bringing the reaction gas into contact with the surface of the wafer W.

As the wafer W, for example, a SiC wafer or a Si wafer can be used. Alternatively, other insulating substrates such as SiO ₂ (quartz) wafers, high-resistance semi-insulating substrates such as GaAs (gallium arsenide) wafers, and the like can be used.

  In order to epitaxially grow SiC, it is necessary to raise the temperature of the wafer W to a temperature of 1500 ° C. or higher. For this reason, it is necessary to use a material having high heat resistance for the susceptor S. Specifically, a surface of isotropic graphite coated with SiC by a CVD (Chemical Vapor Deposition) method is used. The shape of the susceptor S is not particularly limited as long as the wafer W can be placed thereon, and is appropriately selected from a ring shape and a disk shape.

Examples of the reaction gas include silicon (Si) source gas such as silane (SiH ₄ ) and dichlorosilane (SiH ₂ Cl ₂ ), and carbon such as propane (C ₃ H ₈ ) and acetylene (C ₂ H ₂ ). A mixed gas obtained by mixing the source gas (C) and hydrogen (H ₂ ) gas as a carrier gas is introduced.

  In the film forming chamber 2, as shown in FIG. 1, the wafers W are carried in one by one and a film forming process is performed. A plurality of wafers W may be carried in, and film formation processing may be simultaneously performed on these wafers. In this case, the film is formed by a method combining single wafer processing and batch processing, and the productivity of the semiconductor manufacturing apparatus 1 is improved.

  As described above, in the SiC epitaxial growth process, it is necessary to set the wafer W to a very high temperature. However, when the wafer W is heated with a heater to bring it to a high temperature state, the radiant heat from the heater is transmitted not only to the wafer W but also to other members constituting the film forming chamber 2 and raises the temperature thereof. . This is particularly noticeable in members located near high-temperature portions such as the wafer W and heater, the inner wall of the film forming chamber 2, or piping. When the reaction gas comes into contact with the high temperature portion generated in the film formation chamber 2, the reaction gas undergoes a thermal decomposition reaction like the surface of the wafer W heated at a high temperature.

For example, when an SiC epitaxial film is to be formed on the surface of the wafer W, silane (SiH ₄ ) as a Si source, propane (C ₃ H ₈ ) as a C source, hydrogen gas as a carrier gas, etc. A mixed gas prepared by containing is used. The reaction gas is supplied into the film formation chamber 2 from the upper part of the film formation chamber 2 through the introduction port 18, reaches the surface of the wafer W heated at a high temperature, and is decomposed.

  However, since the reaction gas having the above composition is rich in reactivity, when it comes into contact with a member that satisfies a certain temperature condition, a decomposition reaction occurs even if it is not on the wafer W. As a result, the polycrystalline SiC film derived from the reaction gas adheres to the members in the film forming chamber 2, specifically, the susceptor S, the inner wall of the film forming chamber 2, the piping for exhausting the gas in the film forming chamber, and the like. To do. When this film is peeled off, it becomes dust and causes a defect in the epitaxial film formed on the wafer W, so that it is necessary to clean and remove the attached film.

In the present embodiment, as will be described later, the SiC film attached to the susceptor S in the cleaning chamber 5 is removed. On the other hand, with respect to the SiC film adhering to the inner wall or piping of the film forming chamber 2, ClF ₃ gas or the like is introduced from the inlet 18 while the inside of the film forming chamber 2 is at a high temperature, specifically 400 ° C. or higher. The etching can be removed by supplying the etching gas.

As in the case of the susceptor S, the inner wall of the film forming chamber 2 is formed by coating the surface of isotropic graphite with SiC by a CVD (Chemical Vapor Deposition) method. Therefore, it is preferable to manage the etching amount when removing the SiC film adhering to the inner wall by time. The SiC film adhering to the inner wall is considered to be a non-dense polycrystalline film, unlike the dense polycrystalline SiC film constituting the inner wall. The etching rate of this non-dense polycrystalline SiC film is expected to be sufficiently faster than that of a dense polycrystalline SiC film, but since it is the same component, it is selected when 100% ClF ₃ gas is used. The ratio is not enough. Therefore, in the cleaning process, ClF ₃ gas having a concentration of 10% to 20% diluted with hydrogen gas is used as an etching gas. For etching a single crystal SiC film, 100% ClF ₃ gas is usually used. In this case, by using diluted ClF ₃ gas, a dense polycrystalline SiC film and a non-dense polycrystalline film are used. A clear difference can be provided in the etching rate with the SiC film. That is, by utilizing the difference in etching rate and managing the end point of etching by time, the SiC film adhering to the inner wall can be removed by etching without substantially etching the SiC film constituting the inner wall. For the non-dense polycrystalline SiC film adhering to the pipe, the pipe is removed and cleaned with an appropriate chemical solution.

  After the film forming process in the film forming chamber 2 is completed, the first opening / closing unit 3 is opened, and the wafer W is transferred to the transfer chamber 4 by the transfer robot 17.

  The transfer chamber 4 is also provided with an introduction port 15 and an exhaust port 16. The introduction port 15 is connected to a cylinder containing nitrogen gas through a pipe (not shown) so that the nitrogen gas can be introduced into the transfer chamber 4. Further, the exhaust port 16 is connected to a vacuum pump (not shown) through a pipe (not shown), and the gas in the transfer chamber 4 is discharged from here.

  A rotation member 17a is connected to a portion of the transfer robot 17 where the susceptor S and the wafer W are placed, and the distance from the fulcrum portion 17b to the portion where the susceptor S and the wafer W are disposed can be expanded and contracted. It is configured to be possible. The transfer robot 17 is made of, for example, a heat resistant material in which carbon is silicon-coated.

  A heater or a lamp can be provided as a heating means at a portion where the wafer W and the susceptor S of the transfer robot 17 are placed. Thereby, even if the high-temperature wafer W or the susceptor S immediately after being taken out from the film forming chamber 2 or the cleaning chamber 5 is placed, it is possible to prevent a rapid temperature change from occurring. For example, a heater having a tape-like structure in which a heating wire is covered with a flexible heat-resistant resin is provided at a portion where the susceptor S and the wafer W are disposed, and the wafer W is heated by flowing a current through the heating wire. And the temperature of the portion where the susceptor S is disposed can be adjusted. In addition, it is good also as a structure which can heat the whole conveyance chamber 4 from the outside, without providing a heating means in the robot 17 for conveyance.

  After the wafer W is transferred into the transfer chamber 4, the third opening / closing unit 11 is opened, and the transfer robot 17 transfers the wafer W into the first load lock chamber 8.

  The first load lock chamber 8 is provided with an introduction port 13 and an exhaust port 14, and the gas in the first load lock chamber 8 can be discharged from the introduction port 13 using a vacuum pump or the like, and the exhaust port. 14, nitrogen gas, argon gas, or the like can be introduced into the first load lock chamber 8. Further, the first load lock chamber 8 is provided with a fourth opening / closing portion 12, and the wafer W is carried into the first load lock chamber 8 from the outside by opening the fourth opening / closing portion 12. The wafer W can be carried out from the first load lock chamber 8 to the outside.

  After the wafer W after the film forming process is transferred from the third opening / closing part 11 into the first load lock chamber 8, the third opening / closing part 11 is closed, and nitrogen gas is allowed to flow from the introduction port 13 to supply the first opening / closing part 11. Return the load lock chamber 8 to atmospheric pressure. Next, the fourth opening / closing part 12 is opened, and the wafer W is stored in the cassette 27 by the wafer transfer robot 10. On the other hand, with respect to the wafer W before the film forming process, the fourth opening / closing part 12 is opened with the third opening / closing part 11 closed, and the wafer W is carried into the first load lock chamber 8. By providing the first load lock chamber 8, it is possible to prevent outside air from directly entering the transfer chamber 4, the film forming chamber 2, and the cleaning chamber 5. In particular, it is possible to prevent moisture and organic substances in the air from entering the film forming chamber 2 and adversely affecting the film forming process.

  In the semiconductor manufacturing apparatus 1 of the present embodiment, the cleaning chamber 5 is connected to the transfer chamber 4 via the second opening / closing part 6. In the cleaning chamber 5, the susceptor S that has completed the film forming process in the film forming chamber 2 is cleaned. That is, the cleaning chamber 5 is provided for the purpose of removing the SiC film attached to the susceptor S during the SiC epitaxial growth process. By providing the cleaning chamber 5 in the semiconductor manufacturing apparatus 1, it is not necessary to interrupt the film forming process in the film forming chamber 2 and perform the cleaning process. That is, since the cleaning process can be performed in parallel in the cleaning chamber 5 while the film forming process is performed in the film forming chamber 2, the efficiency of the film forming process can be increased.

  The cleaning chamber 5 is provided with an introduction port 20 and an exhaust port 21. The introduction port 20 is connected to a cylinder containing an etching gas through a pipe (not shown), and an appropriate amount of gas is supplied to the cleaning chamber 5 when performing a cleaning process. The exhaust port 21 is connected to a vacuum pump (not shown) through a pipe (not shown) so that the gas in the cleaning chamber 5 is exhausted from here.

As an etching gas, ClF ₃ gas is preferably used. When ClF ₃ gas is supplied to the cleaning chamber 5, it reacts with SiC according to the following formula (1) (Y. Miura, H. Habuka, Y. Katsumi, S. Oda, Y. Fukai, K. Fukae, T Kato, H. Okamura, K. Arai, Japan Journal of Applied Physics. Vol. 46, No. 12, 2007, pp. 7875-7879). By this reaction, the SiC film attached to the susceptor S is removed by etching.

3SiC + 8ClF ₃ → 3SiF ₄ + 3CF ₄ + 4Cl ₂ (1)

  The cleaning chamber 5 is provided with a heating means so that the susceptor S can be heated during the cleaning process. As the heating means, for example, a heater for resistance heating made of a SiC material can be cited, and the susceptor S placed in the cleaning chamber 5 can be heated from below.

Etching of SiC with ClF ₃ gas proceeds at a high temperature. In this embodiment mode, the cleaning process is preferably performed at 400 ° C. or higher. Further, if the temperature is too high, the entire cleaning chamber 5 needs to have high heat resistance. Therefore, the cleaning process is preferably performed at 600 ° C. or lower.

  Further, the cleaning chamber 5 is preferably provided with a rotating means for rotating the susceptor S during cleaning.

In order to advance the reaction of the above formula (1) efficiently, the ClF ₃ gas as the etching gas is efficiently removed while efficiently removing the three kinds of reaction products (3SiF ₄ , 3CF ₄ , 4Cl ₂ ). It is necessary to supply the SiC surface. Therefore, in the semiconductor manufacturing apparatus 1, when supplying the etching gas into the cleaning chamber 5, it is preferable that the etching gas is supplied from above the susceptor S and the cleaning is performed while rotating the susceptor S. . As the susceptor S is rotated at a higher speed, the thickness of the region where the reaction gas reacts (reaction boundary layer) becomes thinner. Then, while the product gas is easily removed, the reaction gas is easily supplied, so that the etching reaction of Formula (1) is likely to occur.

  For example, the susceptor S is carried into the cleaning chamber 5 and the susceptor S is rotated at about 50 rpm. Then, after confirming that the temperature of the susceptor S has reached 400 ° C. or higher by measuring the temperature using a radiation thermometer or the like, the rotational speed of the susceptor S is gradually increased. The rotation speed is preferably 300 rpm to 900 rpm. However, the rotational speed in the cleaning process is not required to be as strict as the rotational speed in the film forming process. Subsequently, an etching gas is supplied from above the susceptor S, and the etching gas is caused to flow toward the susceptor S. At this time, the etching gas is preferably rectified through a rectifying plate such as a shower plate. The etching gas flows substantially vertically toward the susceptor S to form a so-called vertical flow, and is in a rectified state on the surface of the susceptor S. When the etching gas reaches the surface of the heated susceptor S, the reaction of the formula (1) is caused to etch the SiC film attached to the surface of the susceptor S.

  The cleaning process in the cleaning chamber 5 can be performed by unloading the susceptor S from the film forming chamber 2 every time the film forming process in the film forming chamber 2 is completed once. Further, only the wafer W is unloaded from the film formation chamber 2 until the film formation process reaches a predetermined number of times, and after the susceptor S is unloaded together with the wafer W at the predetermined number of times, the susceptor S is removed from the cleaning chamber 5. It is also possible to carry it for cleaning.

  The timing of unloading the susceptor S needs to be performed before particles due to the SiC film attached to the susceptor S start to be generated. If the relationship between the generation of particles and the thickness of the SiC film adhering to the susceptor S can be grasped in advance, it can be determined by the thickness of the SiC film adhering to the surface of the susceptor S. For example, when the thickness of the SiC film deposited on the susceptor S reaches 100 μm, the SiC film can be taken out together with the wafer W to clean the susceptor S. According to the present invention, no matter what timing the susceptor S is carried out, the efficiency of the film forming process is hardly affected.

The end of the cleaning process can be managed by time. Unlike the dense polycrystalline SiC film (SiC film coated on the surface of carbon) constituting the susceptor S, the SiC film adhering to the surface of the susceptor S is considered to be a non-dense polycrystalline film. The etching rate of this non-dense polycrystalline SiC film is expected to be sufficiently faster than that of a dense polycrystalline SiC film, but since it is the same component, the selectivity when using 100% ClF ₃ gas is not enough. Therefore, in the cleaning process, ClF ₃ gas having a concentration of 10% to 20% diluted with hydrogen gas is used as an etching gas. For etching a single crystal SiC film, 100% ClF ₃ gas is usually used. In this case, by using diluted ClF ₃ gas, a dense polycrystalline SiC film and a non-dense polycrystalline film are used. A clear difference can be provided in the etching rate with the SiC film. That is, the SiC film attached to the susceptor S can be etched away without substantially etching the SiC film constituting the susceptor S by using the difference in etching rate and managing the end point of etching by time. it can.
In the above description, the expression of a dense polycrystal and the expression of a non-dense polycrystal are ambiguous. However, in this invention, a dense polycrystal is a single crystal in a polycrystal as compared to a non-dense polycrystal. It is close to crystals.

  After the cleaning process, the susceptor S is transferred to the film forming chamber 4 by the transfer robot 17. Thereafter, the film can be returned to the film forming chamber 2 and subsequently used for the film forming process. Further, it may be transferred from the transfer chamber 4 to the second load lock chamber 24 through the fifth opening / closing part 22 and carried out from the sixth opening / closing part 23 to the outside.

  The second load lock chamber 24 is provided with an exhaust port 25 and an introduction port 26. The gas in the second load lock chamber 24 can be discharged from the exhaust port 25 using a vacuum pump or the like, and the introduction port. 26, nitrogen gas, argon gas, or the like can be introduced into the second load lock chamber 24. Further, by opening the sixth opening / closing part 23 provided in the second load lock chamber 24, the susceptor S can be carried into the second load lock chamber 24 from the outside, or from the second load lock chamber 24. The susceptor S can be carried out to the outside.

  After transporting the susceptor S after the cleaning process from the fifth opening / closing part 22 to the second load lock chamber 24, the fifth opening / closing part 22 is closed, and nitrogen gas is allowed to flow from the introduction port 26 to cause the second load lock. The inside of the chamber 24 is returned to atmospheric pressure. Next, the sixth opening / closing part 23 is opened, and the susceptor S is stored in the cassette 28 by the susceptor transfer robot 7. On the other hand, when carrying the susceptor S from the cassette 28 into the second load lock chamber 24, the sixth opening / closing part 23 is opened with the fifth opening / closing part 22 closed, and the susceptor S is moved to the second load lock chamber 24. Carry it into the chamber 24. Next, after the sixth opening / closing part 23 is closed, the air in the second load lock chamber 24 is discharged from the exhaust port 25 using a vacuum pump or the like. Next, nitrogen gas is introduced into the second load lock chamber 24 through the inlet 26. Argon gas or the like may be introduced instead of nitrogen gas. Thereafter, the fifth opening / closing part 22 is opened and the susceptor S is transferred into the transfer chamber 4.

  By providing the second load lock chamber 24, it is possible to prevent outside air from directly entering the transfer chamber 4, the film forming chamber 2, and the cleaning chamber 5. In particular, it is possible to prevent moisture and organic substances in the air from entering the film forming chamber 2 and adversely affecting the film forming process.

  FIG. 2 is an example of the cleaning chamber of the present embodiment, and is a schematic cross-sectional view showing the configuration thereof.

In FIG. 2, 201 is a chamber, 202 is a hollow cylindrical liner that covers and protects the inner wall of the chamber, 203a and 203b are cooling water passages for cooling the chamber, 20 is an inlet for introducing ClF ₃ gas, 21 Is an outlet for ClF ₃ gas after reaction, S is a susceptor, 208 is a heater that is supported by a support (not shown) and heats the susceptor S, 209 is a flange that connects the upper and lower portions of the chamber 201, and 210 is A packing for sealing the flange portion 209, a flange portion 211 for connecting the exhaust portion 21 and the pipe, and a packing 212 for sealing the flange portion 211 are provided.

  A shower plate 220 is attached to the head of the liner 202. The shower plate 220 is a gas rectifying plate having a function of uniformly supplying the etching gas 225 to the surface of the susceptor S.

  In the cleaning chamber 5, the cleaning process is performed by heating the susceptor S with the heater 208 as the heating unit while rotating the susceptor S with the rotating unit. That is, the susceptor S transported from the transport chamber 4 is placed on the upper portion of the substantially cylindrical rotating unit 232. The rotating part 232 has a lower part than the upper part, and is connected to a rotating mechanism (not shown) outside the chamber 201. The rotation unit 232 rotates at a predetermined number of rotations with a line orthogonal to the center of the horizontal section as a rotation axis. When cleaning is performed, the etching gas for the SiC film is supplied from above the susceptor S by the etching gas supply means while the susceptor S is rotated. Specifically, the etching gas 225 is supplied from the introduction port 20 into the chamber 201 through the through hole 221 of the shower plate 220. The head portion 231 of the liner 202 has a smaller inner diameter than the body portion 230 of the liner 202 on which the susceptor S is placed, and the etching gas 225 passes through the head portion 231 and flows down toward the surface of the susceptor S. .

  In the cleaning chamber 5, the susceptor S is heated by a heater 208 provided below. The shape of the heater is not limited to the structure shown in FIG. 2, and the heater may be heated by two types of heaters, an in-heater and an out-heater.

  In FIG. 2, the susceptor S has a disk shape, and the wafer W is placed on the susceptor S during the film forming process in the film forming chamber 2. The shape of the susceptor S is not limited to this, and may be, for example, a ring shape. Further, the susceptor S may have a shape shown in FIG.

  FIG. 3 is another example of the susceptor S, and is a cross-sectional view of a state where the wafer W is placed and a corresponding top view. In FIG. 3, the susceptor S includes a first member 103 that supports the wafer W, and a second member 107 that is supported by the first member 103 and disposed with a predetermined gap between the wafer W and the second member 107. Consists of.

At the time of film formation, the first member 103 is disposed on the upper part of a substantially cylindrical rotating member (not shown) made of SiC provided in the film formation chamber 2. The first member 103 has a ring shape having an opening at the center, and an upper end and a lower step counterbore are formed at the inner end thereof. The wafer W is placed on the first counterbore 103a which is the upper counterbore. The inner diameter of the first spot facing 103a is slightly larger than the diameter of the wafer W, and the movement of the wafer W in the substantially horizontal direction is restricted. The depth from the upper surface of the first member 103 to the horizontal surface of the first counterbore 103a is substantially the same as or less than the thickness of the wafer W, and the wafer W is mounted on the first counterbore 103a. When placed, the upper surface of the wafer W is at substantially the same position as the upper surface of the first member 103 or higher than the upper surface. Therefore, when the ClF ₃ gas flows from the vicinity of the center of the wafer W toward the peripheral portion, the gas flow does not hit the vertical surface of the first spot facing 103a, and a smooth gas flow is formed.

  In the susceptor S, the second member 107 is placed on the second counterbore 103b which is a lower counterbore. The second member 107 has a larger diameter than the opening formed in the center of the ring-shaped first member 103, and its peripheral end is formed in a collar shape. It is placed so as to be suspended on a horizontal surface. That is, the opening of the first member 103 is covered with the second member 107. The second member 107 is placed on the second spot facing 103b and combined with the first member 103, whereby the susceptor S is completed.

  When the susceptor S has a shape as shown in FIGS. 2 and 3, the cleaning chamber 5 is supplied with an etching gas to perform a cleaning process, and a lower region in the rotating unit 232 is substantially partitioned. Is done. Thereby, it can prevent that the machine and electrical wiring arrange | positioned in the rotation part 232 are corroded by etching gas.

  Further, since the rotation mechanism and the reaction gas supply mechanism of the film forming chamber 2 can be the same as the configuration in the cleaning chamber 5 shown in FIG. Similar effects can be obtained. In other words, since the region where film formation is performed and the lower region in the rotating part are substantially partitioned, the metal constituting the machine and electrical wiring arranged in the rotating part is prevented from being corroded by the reaction gas. Can do. In addition, since impurities derived from such metals are less likely to enter the film forming region, it is possible to prevent impurities from being mixed into the epitaxial film formed on the wafer W and to suppress deterioration in the quality of the epitaxial film. it can.

  As described above, in the cleaning chamber 5, the cleaning process is performed by heating with the heater 208 while rotating the susceptor S. That is, with the susceptor S rotating, the etching gas 225 is supplied from the inlet 20 into the chamber 201 through the through hole 221 of the shower plate 220. The head portion 231 of the liner 202 has a smaller inner diameter than the body portion 230 of the liner 202 on which the susceptor S is placed, and the etching gas 225 flows through the head portion 231 toward the surface of the susceptor S. .

When the etching gas 225 reaches the surface of the susceptor S, the reaction of the above formula (1) occurs, and the SiC film attached to the surface of the susceptor S is etched. The gas generated as a result of the reaction and the unreacted ClF ₃ gas are exhausted from the exhaust port 21 provided in the lower part of the chamber 201 as needed.

  Packings 210 and 212 are used for sealing the flange portion 209 of the chamber 201 and the flange portion 211 of the exhaust port 25 for sealing. On the outer peripheral portion of the chamber 201, flow paths 203a and 203b for circulating cooling water are provided, and the packings 210 and 212 are prevented from being deteriorated by heat.

  The temperature during the cleaning treatment is preferably 400 ° C. or higher, and more preferably 600 ° C. or lower.

  The surface temperature of the susceptor S can be measured by a radiation thermometer 226 provided at the top of the chamber 201. A specific example of the radiation thermometer 226 is a fiber radiation thermometer. The thermometer includes an optical lens that collects radiated light emitted from the object to be measured, an optical fiber that transmits the radiated light collected by the optical lens to a temperature conversion unit, and a lens holder that holds the optical lens. A light receiving unit case that supports and fixes the end face of the optical fiber, and a temperature conversion unit that measures the temperature of the object to be measured based on the intensity of the light transmitted by the optical fiber. For example, by making the shower plate 220 made of transparent quartz, the radiation thermometer 226 can receive the radiated light from the susceptor S through the shower plate 220. The measured temperature data is sent to a control mechanism (not shown) and then fed back to the output control of the heater 208. Thereby, the susceptor S can be heated to a desired temperature. However, the temperature management in the cleaning process does not require as strictness as the temperature management in the film forming process.

  As described above, the semiconductor manufacturing apparatus of the present embodiment includes the cleaning chamber for cleaning the susceptor, and therefore does not require interruption of the film forming process due to the cleaning process. In addition, since the cleaning chamber is configured to supply an etching gas to the surface of the susceptor while heating and rotating the susceptor, the SiC film attached to the susceptor can be efficiently removed by etching.

  Also, according to the susceptor cleaning method of the present embodiment, the etching gas is supplied to the surface of the susceptor from above while the susceptor is heated and rotated, so that the SiC film adhering to the susceptor can be efficiently removed by etching. Can do.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Semiconductor manufacturing apparatus 2 Film-forming chamber 3 1st opening / closing part 4 Transfer chamber 5 Cleaning chamber 6 2nd opening / closing part 7 Susceptor transfer robot 8 1st load lock chamber 10 Wafer transfer robot 11 3rd opening / closing part 12 Fourth opening / closing portion 17 Transfer robot 18, 20, 13, 15, 26 Inlet port 19, 21, 14, 16, 25 Exhaust port 22 Fifth opening / closing portion 23 Sixth opening / closing portion 24 Second load lock chamber 27, 28 Cassette W Wafer S Susceptor 103 First member 103a First counterbore 103b Second counterbore 107 Second member 201 Chamber 202 Liner 203a, 203b Flow path 208 Heater 209, 211 Flange part 210, 212 Packing 220 Shower Plate 221 Through-hole 225 Etching gas 230 Body 231 Head 226 Radiation temperature 232 rotating part

Claims (5)

A film forming chamber for forming a SiC epitaxial film on a wafer placed on a susceptor;
A cleaning chamber connected to the film forming chamber via a transfer chamber having a transfer means for transferring the susceptor, and removing a SiC film adhering to the susceptor;
The cleaning chamber comprises heating means for heating the susceptor at a temperature of 400 ° C. or higher;
Etching gas supply means for supplying an etching gas from above the susceptor to remove the SiC film.   The semiconductor manufacturing apparatus according to claim 1, further comprising a rotating unit that rotates the susceptor at 300 rpm to 900 rpm. A method of cleaning a susceptor used in a SiC epitaxial growth process,
A method of cleaning a susceptor, wherein a SiC film adhering to the susceptor is removed by supplying ClF ₃ gas from above the susceptor while heating the susceptor at a temperature of 400 ° C. or higher. 4. The susceptor cleaning method according to claim 3, wherein the SiC film attached to the susceptor is removed by heating the susceptor while rotating and supplying ClF ₃ gas from above the susceptor.   The susceptor cleaning method according to claim 3 or 4, wherein the temperature of the susceptor is set to 600 ° C or lower.

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