Epitaxial wafer manufacturing method and epitaxial wafer manufacturing apparatus

Abstract

To suppress distortion of a wafer in manufacturing an epitaxial wafer through a multi-wafer deposition process.SOLUTION: The present invention relates to a manufacturing method of an epitaxial wafer including cleaning the inside of a chamber 11 after executing a plurality of times an epitaxial wafer manufacturing process of: carrying a wafer W into the chamber 11 of an epitaxial wafer manufacturing device 1; growing an epitaxial film on the wafer W and defining it as an epitaxial wafer; and carrying the epitaxial wafer out of the chamber 11. In the manufacturing method of the epitaxial wafer, the wafer W supported by a susceptor 12 is heated by first heating devices 24 and 25 during the growth of the epitaxial film, and an outer edge of the susceptor 12 is heated by a second heating device 27.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an epitaxial wafer manufacturing method and epitaxial wafer manufacturing apparatus for vapor-phase growing an epitaxial film on a wafer. [Background technology]

[0002] 2. Description of the Related Art Known epitaxial wafer manufacturing apparatus for growing an epitaxial film on a wafer includes an apparatus in which a source gas is introduced into a chamber, and the source gas is thermally decomposed or reduced to produce a source material, which is then vapor-grown as an epitaxial film on a wafer heated to a high temperature.

[0003] During epitaxial growth, temperature is strictly controlled to prevent defects such as dislocations and atomic-level distortion of the single crystal. Patent Document 1 discloses a technique that includes a step of measuring the temperature of the outer periphery of the epitaxial wafer and a step of measuring the temperature of the susceptor, and that suppresses the occurrence of dislocations at the contact portion between the epitaxial wafer and the susceptor by heating the susceptor or the epitaxial wafer so that the difference between the temperature of the outer periphery of the epitaxial wafer and the temperature of the susceptor falls within a predetermined range. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-141060 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, in a method for producing an epitaxial wafer, it is common to carry the wafer into a chamber, grow an epitaxial film thereon, and then carry the wafer out of the chamber, after which the inside of the chamber is cleaned. On the other hand, since cleaning every time a wafer is carried out is disadvantageous in terms of total manufacturing costs, a multi-wafer deposition process is also known in which cleaning is performed after the epitaxial wafer manufacturing process consisting of carrying in the wafer, growing the epitaxial film, and carrying out the wafer is repeated multiple times. In other words, in the epitaxial wafer manufacturing method using the multi-wafer deposition process, the frequency of cleaning is reduced to reduce costs. However, when the technique of Patent Document 1 is applied to a multi-wafer deposition process, there is a problem in that distortion occurs in the wafer even when strict temperature control is performed.

[0006] An object of the present invention is to provide an epitaxial wafer manufacturing method and epitaxial wafer manufacturing apparatus capable of suppressing distortion of a wafer in the manufacture of epitaxial wafers by a multi-wafer deposition process. [Means for solving the problem]

[0007] The inventors believed that the cause of distortion in wafers during the manufacture of epitaxial wafers by a multi-wafer deposition process is a change in temperature at the outer edge of the susceptor due to by-products such as polysilicon that accumulate on the outer edge of the susceptor during the growth of the epitaxial film. They then completed the present invention, which is capable of preventing wafer distortion by creating a manufacturing method and manufacturing apparatus that take into account the deposition of these by-products.

[0008] The epitaxial wafer manufacturing method of the present invention is a method for manufacturing an epitaxial wafer, which includes carrying out an epitaxial wafer manufacturing process multiple times, in which a wafer is carried into a chamber of an epitaxial wafer manufacturing apparatus, an epitaxial film is grown on the wafer to form an epitaxial wafer, and the epitaxial wafer is carried out of the chamber, and then cleaning the inside of the chamber, and is characterized in that during the growth of the epitaxial film, the wafer supported by a susceptor is heated by a first heating device, and the outer edge of the susceptor is heated by a second heating device.

[0009] In the above-described method for producing an epitaxial wafer, it is preferable to measure the temperature of the outer periphery of the wafer or the outer edge of the susceptor, and heat the outer edge of the susceptor with a second heating device based on the measured temperature.

[0010] In the above-mentioned method for manufacturing an epitaxial wafer, it is desirable to measure the temperature of the outer edge of the susceptor, and heat the outer edge of the susceptor with the second heating device so that the temperature difference between the temperature of the center of the wafer and the temperature of the outer edge of the susceptor does not vary between wafers.

[0011] In the above-described method for producing an epitaxial wafer, an outer edge portion of the susceptor may be heated by the second heating device based on preset heating conditions.

[0012] The epitaxial wafer manufacturing method of the present invention is a method for manufacturing an epitaxial wafer, which includes carrying out an epitaxial wafer manufacturing process multiple times, in which a wafer is carried into a chamber of an epitaxial wafer manufacturing apparatus, an epitaxial film is grown on the wafer to form an epitaxial wafer, and the epitaxial wafer is carried out of the chamber, and then cleaning the inside of the chamber, and is characterized in that during the growth of the epitaxial film, the wafer supported by a susceptor is heated by a first heating device, and the temperature of the outer periphery of the wafer or the outer edge of the susceptor is measured, and the outer periphery of the wafer is heated by a second heating device based on the measured temperature.

[0013] In the above-mentioned method for manufacturing an epitaxial wafer, the temperature of the outer periphery of the wafer may be measured, and the outer periphery of the wafer may be heated so that the temperature difference between the center of the wafer and the outer periphery of the wafer does not vary between wafers.

[0014] In the above-described method for producing an epitaxial wafer, an outer periphery of the wafer may be heated by the second heating device based on preset heating conditions.

[0015] The epitaxial wafer manufacturing apparatus of the present invention is characterized by comprising a first heating device that heats a wafer supported by a susceptor, a temperature measuring device that measures the temperature of the outer periphery of the wafer or the outer edge of the susceptor, a second heating device that heats the outer edge of the susceptor, and a control device that controls the second heating device based on the temperature.

[0016] In the above-described epitaxial wafer manufacturing apparatus, it is preferable that the second heating device is a laser heating device.

[0017] The epitaxial wafer manufacturing apparatus of the present invention is characterized by comprising a first heating device that heats a wafer supported by a susceptor, a temperature measuring device that measures the temperature of the outer periphery of the wafer or the outer edge of the susceptor, a second heating device that heats the outer periphery of the wafer, and a control device that controls the second heating device based on the temperature. [Brief description of the drawings]

[0018] [Figure 1] 1 is a schematic diagram of an epitaxial wafer manufacturing apparatus according to a first embodiment of the present invention. [Diagram 2] 2 is a cross-sectional view of a susceptor of the epitaxial wafer manufacturing apparatus according to the first embodiment of the present invention. FIG. [Diagram 3] 1 is a flowchart of a method for producing an epitaxial wafer according to a first embodiment of the present invention. [Figure 4] 4 is a flowchart of an epitaxial film forming process according to the first embodiment of the present invention. [Diagram 5] FIG. 4 is a schematic diagram of an epitaxial wafer manufacturing apparatus according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First Embodiment FIG. 1 is a schematic diagram of an epitaxial wafer manufacturing apparatus according to a first embodiment of the present invention. As shown in FIG. 1, the epitaxial wafer manufacturing apparatus 1 is of a single-wafer type that processes wafers W one by one, and includes an apparatus main body 2, a control device 3, and a wafer transfer mechanism 4. The wafer W may be, for example, a silicon wafer, a GaAs wafer, an InP wafer, a ZnS wafer, a ZnSe wafer, or an SOI wafer.

[0020] The apparatus body 2 includes a chamber 11 in which a wafer W is accommodated, a susceptor 12 that horizontally supports the wafer W from its lower surface side in the chamber 11, a support member driving mechanism 23, and a gas supply device 29. The susceptor 12 is rotatably supported by a susceptor support member 13.

[0021] The chamber 11 includes an annular base 31, an upper dome 32 that covers the upper side of the accommodated wafer W, and a lower dome 33 that covers the lower side of the wafer W. The base 31 is provided with a gas inlet 31A for introducing gas G into the chamber 11 and a gas outlet 31B for discharging gas G to the outside of the chamber 11 at positions facing each other in the horizontal direction.

[0022] The gas supply device 29 introduces a carrier gas (e.g., hydrogen (H2)) together with a source gas (e.g., trichlorosilane (SiHCl3)) and, if necessary, a dopant gas (e.g., diborane (B2H6)) from the gas inlet 31A into the upper space in the chamber 11. These gases are exhausted from the gas outlet 31B.

[0023] A heat ring 19 is attached to the inside of the base 31 to preheat the susceptor 12 and the introduced gas G. The heat ring 19 preheats the susceptor 12 and trichlorosilane before the trichlorosilane comes into contact with the wafer W. This improves the thermal uniformity of the wafer W before and during film formation, improving the uniformity of the epitaxial film. The heat ring 19 also prevents the gas G from flowing around to the bottom of the chamber 11. The heat ring 19 may be formed, for example, from a carbon substrate coated with silicon carbide (SiC).

[0024] A cylindrical body 33A extending downward is formed in the center of the lower dome 33. An inner main pillar 51 constituting the susceptor support member 13 supporting the susceptor 12 and an outer main pillar 61 constituting a part of the lift pin support member 22 and arranged axially slidably on the outer periphery of the inner main pillar 51 are inserted into the cylindrical body 33A. An outer arm 62 is provided on the upper end of the outer main pillar 61.

[0025] The base 31 may be made of, for example, stainless steel. The upper dome 32 and the lower dome 33 may be made of, for example, transparent quartz that does not block heat rays such as infrared rays from the upper lamps 24 (first heating device) and the lower lamps 25 (first heating device) that heat the wafer W and the susceptor 12 in the chamber 11.

[0026] The susceptor 12 is a disk-shaped member on which the wafer W is placed in the chamber 11. As shown in FIG. 2, an annular outer edge 14 is formed on the outermost periphery of the upper surface of the susceptor 12, and a circular recess 15 is formed on the inner periphery side of the outer edge 14. The recess 15 is formed with a diameter slightly larger than that of the wafer W in order to accommodate the wafer W. A protrusion 16 is provided on the outermost periphery of the recess 15, protruding above the bottom surface of the recess 15. The protrusion 16 supports the outer edge of the wafer W. The susceptor 12 can be formed of, for example, a carbon substrate coated with silicon carbide.

[0027] As shown in FIG. 1, the susceptor support member 13 supports the susceptor 12 by means of a cylindrical inner main pillar 51 and a plurality of arms 52 extending radially from the tip of the inner main pillar 51 .

[0028] The lift pin 21 has a cylindrical shaft portion and a truncated cone-shaped head portion that is provided at the upper end of the shaft portion and has a diameter that increases toward the top. The head portion of the lift pin 21 is supported by the susceptor 12. The lift pins 21 may be formed, for example, of silicon carbide, quartz, a carbon substrate, glassy carbon, or a carbon substrate coated with silicon carbide. The lower end of each lift pin 21 is supported by a lift pin support member 22 when it slides up and down.

[0029] The lift pin support member 22 includes a cylindrical outer main pillar 61, a plurality of outer arms 62 extending radially from the tip of the outer main pillar 61, and abutment portions 63 provided at the tip of each of the outer arms 62. Each abutment portion 63 abuts against the lower end of the corresponding lift pin 21 to support it when it is moved.

[0030] The support member driving mechanism 23 rotates the susceptor support member 13 and raises and lowers the lift pin support member 22 .

[0031] A first pyrometer 28A is attached above the chamber 11 and above the center of the wafer W. The first pyrometer 28A senses thermal radiation from the wafer W and measures the surface temperature of the wafer W in a non-contact manner. Above the chamber 11, upper lamps 24 are provided for heating the wafer W and the susceptor 12 from above.

[0032] A second pyrometer 28B is attached below the chamber 11. The second pyrometer 28B measures the temperature of the center of the susceptor 12 in a non-contact manner. Below the chamber 11, a lower lamp 25 is provided for heating the susceptor 12 from below.

[0033] The upper lamps 24 and the lower lamps 25 are composed of a plurality of horizontally placed upper halogen lamps 71 and a plurality of lower halogen lamps 72, which are arranged in a ring shape. Note that the arrangement of the upper lamps 24 and the lower lamps 25 is not limited to this, and for example, in order to increase the amount of heat from below, further halogen lamps may be arranged in a ring shape inside the lower halogen lamps 72 which are arranged in a ring shape.

[0034] In addition to the first pyrometer 28A and the second pyrometer 28B, a third pyrometer 28C (temperature measuring device) that measures the temperature of the outer edge 14 of the susceptor 12 is attached above the chamber 11. The third pyrometer 28C is not placed directly above the outer edge 14 of the susceptor 12 to avoid interference with the upper lamps 24, but is placed inside the upper lamps 24. The third pyrometer 28C may also be placed outside the upper lamps 24.

[0035] Furthermore, an auxiliary heating device 27 (second heating device) for heating the outer edge 14 of the susceptor 12 is provided above the chamber 11. The auxiliary heating device 27 is oriented so as to heat the outer edge 14 of the susceptor 12. The auxiliary heating device 27 is preferably a device that has directionality and can concentrate heating on a small point of about 10 mm in diameter by the focusing effect of a lens, and for example, a laser heating device such as a YAG laser or a YLF laser can be used. As the auxiliary heating device 27, a heating device that heats by radiating heat from infrared rays can also be used. In the apparatus main body 2 of this embodiment, one each of third pyrometer 28C and auxiliary heating device 27 is provided. Third pyrometer 28C and auxiliary heating device 27 are directed toward one point on outer edge portion 14 of susceptor 12, but rotation of susceptor 12 allows measurement and heating over the entire circumferential direction of outer edge portion 14. Note that multiple third pyrometers 28C and auxiliary heating devices 27 may be provided. Furthermore, auxiliary heating device 27 may be provided on the lower side of chamber 11.

[0036] The control device 3 controls the wafer transport mechanism 4 , the support member driving mechanism 23 , the upper lamps 24 , the lower lamps 25 , the auxiliary heating device 27 , and the gas supply device 29 .

[0037] The memory device of the control device 3 stores a manufacturing program related to the process sequence and control parameters (control target values ​​such as temperature, pressure, type of gas and gas flow rate, and deposition time) for manufacturing epitaxial wafers, and also includes the process sequence and data (such as a calibration curve for the growth temperature) for managing the temperature (in particular, the set temperature of the wafer W in the chamber 11).

[0038] When manufacturing an epitaxial wafer, the control device 3 reads out a manufacturing program from the storage device, and controls the wafer transport mechanism 4, the support member driving mechanism 23, the upper lamp 24, the lower lamp 25, and the gas supply device 29.

[0039] During temperature control, the control device 3 reads out the manufacturing program from the storage device, and controls the temperature (particularly the set temperature of the wafer W in the chamber 11) based on the manufacturing program and measurement data.

[0040] The wafer transport mechanism 4 loads the wafer W into the chamber 11 and loads the wafer W out of the chamber 11 through a wafer load / unload port (not shown) of the chamber 11 .

[0041] [Method for manufacturing epitaxial wafer] Next, a method for manufacturing an epitaxial wafer using the epitaxial wafer manufacturing apparatus 1 will be described. The epitaxial wafer manufacturing method is a method in which epitaxial films are grown on a plurality of wafers W in sequence using an epitaxial wafer manufacturing apparatus 1.

[0042] As shown in Figure 3, the manufacturing method of an epitaxial wafer includes a wafer preparation process S1 for preparing multiple wafers W, a wafer loading process S2 for loading the wafers W, an epitaxial film formation process S3 for forming an epitaxial film E on the wafers W, a wafer unloading process S4 for unloading the wafers W, a cleaning process S5 for cleaning the inside of the chamber 11, and a determination process S6 for determining whether the epitaxial film E has been grown (completed or not) on all of the prepared wafers W. Here, the three steps of the wafer loading step S2, the epitaxial film forming step S3, and the wafer unloading step S4 are referred to as an epitaxial wafer manufacturing process.

[0043] In the epitaxial wafer manufacturing method of this embodiment, the counter is programmed to execute the cleaning step S5 after executing the epitaxial film manufacturing step five times. In this embodiment, the epitaxial wafer manufacturing process is performed five times before the cleaning process S5 is performed, but the number of times is not limited to this as long as it is performed a plurality of times (for example, from two to nine times).

[0044] In other words, the epitaxial wafer manufacturing method of the present invention is a manufacturing method using a multi-wafer deposition process in which the epitaxial wafer manufacturing process consisting of loading the wafer W, growing the epitaxial film E, and unloading the wafer W is repeated multiple times, followed by cleaning.

[0045] The wafer preparation step S1 is a step of preparing a wafer W. The diameter of the wafer W may be any one of 200 mm, 300 mm, 450 mm, and the like.

[0046] In the wafer carry-in step S2, the controller 3 controls the wafer transport mechanism 4 to carry the wafer W into the chamber 11 through a wafer carry-in / out port (not shown) of the chamber 11 and stop the wafer W on the recess 15 of the susceptor 12. Next, the controller 3 controls the support member drive mechanism 23 to raise the lift pin support member 22 and raise the lift pins 21 supported by the susceptor 12, thereby lifting the wafer W and receiving the wafer W from the wafer transport mechanism 4.

[0047] Next, the controller 3 controls the support member driving mechanism 23 to lower the lift pin support member 22 , thereby placing the wafer W in the recess 15 of the susceptor 12 .

[0048] Next, the epitaxial film forming step S3 will be described in detail. The epitaxial film forming step S3 is a step of growing an epitaxial film E on the carried-in wafer W to form an epitaxial wafer. As shown in FIG. 4, the epitaxial film formation step S3 includes a gas introduction step S31, a wafer heating step S32, a temperature measurement step S33, an epitaxial film growth step S34, a temperature difference determination step S35, a heating step S36, and a growth time determination step S37.

[0049] In the gas introduction step S31, the controller 3 controls the gas supply device 29 to start introducing hydrogen gas as a carrier gas from the gas inlet 31A. The controller 3 creates a hydrogen atmosphere in the chamber 11 by continuously introducing hydrogen gas while discharging it from the gas outlet 31B. In addition, the controller 3 controls the support member driving mechanism 23 to rotate the susceptor support member 13 at the same time as the introduction of hydrogen gas.

[0050] In the wafer heating step S32, the controller 3 controls the upper lamps 24 and the lower lamps 25 to further heat the wafer W to a film formation set temperature while measuring the surface temperature of the wafer W with the first pyrometer 28A. In this embodiment, trichlorosilane (SiHCl3) is used as the source gas, and the film formation set temperature is set to a temperature range lower than 1,200°C.

[0051] In the temperature measuring step S33, the temperature of the central portion P1 of the wafer W is measured using the first pyrometer 28A, and the temperature of the outer periphery 14 of the susceptor 12 is measured using the third pyrometer 28C.

[0052] In the epitaxial film growth process S34, the control device 3 measures the surface temperature of the wafer W using the first pyrometer 28A, while controlling the upper lamps 24 and the lower lamps 25 to increase the temperature in the chamber 11, and controls the gas supply device 29 to supply trichlorosilane from the gas inlet 31A to the upper space in the chamber 11.

[0053] When the rotation of the susceptor 12 and the temperature of the wafer W have stabilized, various gases are supplied to grow an epitaxial film E uniformly on the wafer W.

[0054] Next, the temperature difference determining step S35 and the heating step S36 will be described. First, the by-product B generated during the growth of the epitaxial film E and the control of the auxiliary heating device 27 will be described. During the growth of the epitaxial film E, a by-product B (polysilicon, see FIG. 2) accompanying the epitaxial growth process is deposited on the outer edge 14 of the susceptor 12. The deposition of the by-product B on the outer edge 14 of the susceptor 12 reduces the efficiency of heating the outer edge of the susceptor 12 by the upper lamps 24.

[0055] Specifically, when the deposition of by-product B is small, the difference in temperature between the center P1 of the wafer W and the temperature inside P3 of the outer edge 14 of the susceptor 12 is small, and the difference in temperature between the center P1 of the wafer W and the temperature inside P2 of the wafer W is also small. However, since the by-product B has a low absorptivity of the infrared rays irradiated from the lamp, when the by-product B is deposited in a large amount, the inside P3 of the outer peripheral portion 14 of the susceptor 12 is not easily heated. This increases the difference in temperature between the center P1 of the wafer W and the inside P3 of the outer peripheral portion 14 of the susceptor 12, and also increases the difference in temperature between the center P1 of the wafer W and the outer peripheral portion P2 of the wafer W that contacts the outer peripheral portion 14 of the susceptor 12 via the protrusion 16. This temperature difference between the center P1 and the outer peripheral portion P2 of the wafer W causes atomic-level distortion in the wafer W and reduces the thickness of the epitaxial film E on the outer peripheral portion P2 of the wafer W.

[0056] The distortion of the wafer W can be measured using a distortion measuring device (SIRD device) that utilizes infrared photoelasticity. Moreover, the "periphery of the wafer W" refers to the peripheral portion of the disk-shaped wafer W that is from the outer periphery to 3% of the diameter.

[0057] In order to suppress this distortion, the control device 3 measures the temperature of the outer edge 14 of the susceptor 12 using a third pyrometer 28C, and controls the auxiliary heating device 27 based on the measured temperature to heat the outer edge 14 of the susceptor 12.

[0058] Specifically, in the temperature difference determination step S35, it is determined whether the temperature difference between the temperature of the central portion P1 of the wafer W and the temperature of the outer periphery 14 of the susceptor 12 measured in the temperature measurement step S33 is equal to or less than a predetermined threshold value (for example, 5° C.). If the temperature difference is equal to or less than the predetermined threshold, heating using only the lamps is continued without using the auxiliary heating device 27 (heating step S36A). On the other hand, if the temperature difference is greater than the predetermined threshold, in addition to heating using the lamps, the outer edge 14 of the susceptor 12 is heated (laser heating) by the auxiliary heating device 27 (heating step S36B). That is, in order to compensate for the decrease in heating efficiency of the outer edge 14 of the susceptor 12 due to the deposition of by-product B, the control device 3 heats the outer edge 14 of the susceptor 12 so that the temperature difference between the center P1 of the wafer W and the temperature inside P3 of the outer edge of the susceptor 12 does not change among the multiple wafers W being manufactured.

[0059] Control of the auxiliary heating device 27 based on the temperature of the outer edge 14 of the susceptor 12 may be performed from the first epitaxial wafer manufacturing process to the fifth epitaxial wafer manufacturing process, or may not be performed in the first epitaxial wafer manufacturing process but may be performed from the second epitaxial wafer manufacturing process onwards.

[0060] In the growth time determination step S37, it is determined whether or not a predetermined epitaxial film growth time has been reached. If the predetermined epitaxial film growth time has been reached, the epitaxial film formation step S3 is terminated, and if the predetermined epitaxial film growth time has not been reached, the growth of the epitaxial film E is continued.

[0061] Next, the wafer unloading step S4, the cleaning step S5, and the determining step S6 will be described with reference to FIG. After the epitaxial film E is formed, in the wafer unloading step S14, the controller 3 measures the surface temperature of the wafer W with the first pyrometer 28A, while controlling the upper lamps 24 and the lower lamps 25 to lower the temperature of the wafer W from the set temperature during film formation to the set temperature during transport. Next, the controller 3 controls the support member driving mechanism 23 to raise the lift pin support member 22, and the lift pins 21 lift the wafer W from the susceptor 12. Next, the controller 3 controls the wafer transport mechanism 4 to move it into the chamber 11 and stop it below the wafer W.

[0062] Next, the controller 3 controls the support member driving mechanism 23 to lower the lift pin support member 22 and transfer the wafer W to the wafer transfer mechanism 4. Next, the controller 3 controls the wafer transfer mechanism 4 to transfer the wafer W to the outside of the chamber 11.

[0063] Next, the control device 3 controls the wafer transport mechanism 4 to load a new wafer W into the chamber 11, and then performs the same series of processes as those described above to manufacture a new epitaxial wafer.

[0064] The control device 3 performs the above-described epitaxial wafer manufacturing process five times to manufacture five epitaxial wafers, and then performs a cleaning process S5. The cleaning step S5 is a step of supplying hydrogen chloride gas from the gas inlet 31A into the chamber 11 to clean the inside of the chamber 11. By the introduction of the hydrogen chloride gas, the hydrogen chloride gas reacts with the by-product B, and the by-product B is etched and removed.

[0065] In a determination step S6, it is determined whether or not the epitaxial film E has been formed on all of the prepared wafers W. If the formation has been completed on all of the wafers W, the method for manufacturing the epitaxial wafer is terminated.

[0066] According to the above embodiment, in a so-called multi-wafer deposition process in which a cleaning process is performed after performing an epitaxial wafer manufacturing process multiple times, the outer peripheral portion 14 of the susceptor 12 is heated based on the temperature of the outer peripheral portion 14 of the susceptor 12, thereby suppressing a change in the temperature difference between the center portion P1 of the wafer W and the temperature inside P3 of the outer peripheral portion 14 of the susceptor 12. This makes it possible to suppress distortion of the wafer W caused by the temperature difference between the center portion P1 of the wafer W and the temperature of the outer peripheral portion P2 of the wafer W.

[0067] Furthermore, by adopting a configuration in which the outer edge 14 of the susceptor 12 is heated instead of the wafer W, the present invention can also be applied to the manufacture of wafers in which slip dislocations or the like occur when heated directly. Furthermore, by employing a laser heating device as the auxiliary heating device 27, it is possible to concentrate heating on only the surface of the outer edge portion 14 of the susceptor 12.

[0068] Second Embodiment Hereinafter, a method for producing an epitaxial wafer and an epitaxial wafer production apparatus according to a second embodiment of the present invention will be described. Note that in this embodiment, the description of the same configuration as in the first embodiment will be omitted. In the first embodiment, the auxiliary heating device 27 is configured to heat the outer peripheral portion 14 of the susceptor 12, but as shown in Fig. 5, the auxiliary heating device 27B of this embodiment is configured to heat the outer peripheral portion P2 of the wafer W. That is, the auxiliary heating device 27B of this embodiment is oriented so as to heat the outer peripheral portion P2 of the wafer W. Additionally, the third pyrometer 28D of this embodiment is oriented to measure the temperature of the outer periphery P2 of the wafer W.

[0069] The control device 3 of the present embodiment controls the auxiliary heating device 27B to heat the outer periphery P2 of the wafer W based on the temperature of the outer periphery P2 of the wafer W measured by the third pyrometer 28D. Specifically, the control device 3 heats the outer periphery P2 of the wafer W so that the temperature difference between the center portion P1 of the wafer W and the temperature of the outer periphery P2 of the wafer W does not change.

[0070] According to the above embodiment, by adopting a configuration in which the outer periphery P2 of the wafer W is directly heated, the temperature of the outer periphery P2 of the wafer W can be changed more quickly and controlled without causing unnecessary thermal distortion.

[0071] In each of the above embodiments, the auxiliary heating device 27 is controlled so as not to change the temperature difference between the temperature of the center P1 of the wafer W and the temperature of the outer edge 14 of the susceptor 12 (or the temperature of the outer periphery P2 of the wafer W), but this is not limited to the above. For example, the auxiliary heating device 27 may be controlled based on preset heating conditions without measuring the temperature during the manufacture of the epitaxial wafer. Specifically, epitaxial wafers are manufactured by a multi-wafer deposition process multiple times in order to determine in advance the heating conditions for the outer edge 14 of the susceptor 12. During this process, the outer edge 14 of the susceptor 12 (or the outer periphery P2 of the wafer W) is heated while changing the heating conditions by the auxiliary heating device 27, and the heating conditions that produced the best quality wafers for each iteration of the epitaxial wafer manufacturing process are adopted as the heating conditions for the actual manufacture of the epitaxial wafers. The heating conditions may be determined by measuring the temperatures of the wafer and the susceptor using a pyrometer and checking the temperature difference therebetween.

[0072] In addition, in each of the above embodiments, the thickness of the accumulated by-product B is not taken into consideration, but the thickness of the by-product B may be measured or estimated, and the amount of heat applied by the auxiliary heating device 27 may be changed according to the thickness.

[0073] In each of the above embodiments, the auxiliary heating device 27 is controlled based on the temperature of the center P1 of the wafer W measured by the first pyrometer 28A and the temperature of the outer edge 14 of the susceptor 12 or the outer periphery P2 of the wafer W measured by the third pyrometers 28C and 28D, but the present invention is not limited to this. For example, the auxiliary heating device 27 may be controlled in consideration of the temperature of the center P4 of the susceptor 12 (see FIG. 2) measured by the second pyrometer 28B.

[0074] Furthermore, in each of the above embodiments, a laser heating device is used as the auxiliary heating device 27 (second heating device), but this is not limited thereto, and for example, a halogen lamp, a xenon lamp, or the like can also be used as the device. [Explanation of symbols]

[0075] 1... epitaxial wafer manufacturing apparatus, 2... apparatus main body, 3... control device, 4... wafer transfer mechanism, 11... chamber, 12... susceptor, 13... susceptor support member, 15... recess, 16... protrusion, 19... heat ring, 24... upper lamp (first heating device), 25... lower lamp (first heating device), 27... auxiliary heating device (second heating device), 28A... first pyrometer, 28B... second pyrometer, 28C... third pyrometer, 29... gas supply device, 31... base, 31A... gas inlet, 31B... gas outlet, 32... upper dome, 33... lower dome, B... by-product, P1... center of wafer, P2... outer periphery of wafer, P3... inside of outer edge of susceptor, P4... center of susceptor, W... wafer.

Claims

1. 1. A method for manufacturing an epitaxial wafer, comprising the steps of: carrying a wafer into a chamber of an epitaxial wafer manufacturing apparatus; growing an epitaxial film on the wafer to form an epitaxial wafer; and carrying the epitaxial wafer out of the chamber; and then cleaning the inside of the chamber, the method comprising the steps of: A method for manufacturing an epitaxial wafer, wherein, during growth of the epitaxial film, the wafer supported by a susceptor is heated by a first heating device, and an outer edge portion of the susceptor is heated by a second heating device.

2. 2. A method for producing an epitaxial wafer according to claim 1, comprising: A method for manufacturing an epitaxial wafer, comprising measuring a temperature of an outer periphery of the wafer or an outer edge of the susceptor, and heating the outer edge of the susceptor with a second heating device based on the measured temperature.

3. 3. A method for producing an epitaxial wafer according to claim 2, comprising: A method for manufacturing an epitaxial wafer, comprising: measuring a temperature of the outer edge of the susceptor; and heating the outer edge of the susceptor with the second heating device so that the temperature difference between the temperature of the center of the wafer and the temperature of the outer edge of the susceptor does not vary between wafers.

4. 2. A method for producing an epitaxial wafer according to claim 1, comprising: A method for manufacturing an epitaxial wafer, comprising: heating an outer edge portion of the susceptor by the second heating device based on preset heating conditions.

5. 1. A method for manufacturing an epitaxial wafer, comprising the steps of: carrying a wafer into a chamber of an epitaxial wafer manufacturing apparatus; growing an epitaxial film on the wafer to form an epitaxial wafer; and carrying the epitaxial wafer out of the chamber; and then cleaning the inside of the chamber, the method comprising the steps of: A method for manufacturing an epitaxial wafer, comprising: heating the wafer supported by a susceptor with a first heating device during growth of the epitaxial film; measuring the temperature of the outer periphery of the wafer or the outer edge of the susceptor; and heating the outer periphery of the wafer with a second heating device based on the measured temperature.

6. 6. A method for producing an epitaxial wafer according to claim 5, comprising the steps of: A method for manufacturing an epitaxial wafer, comprising measuring a temperature of the outer periphery of the wafer, and heating the outer periphery of the wafer so that the temperature difference between the center of the wafer and the outer periphery of the wafer does not vary between wafers.

7. 6. A method for producing an epitaxial wafer according to claim 5, comprising the steps of: A method for manufacturing an epitaxial wafer, comprising heating an outer periphery of the wafer by the second heating device based on preset heating conditions.

8. a first heating device for heating the wafer supported by the susceptor; a temperature measuring device for measuring the temperature of the outer periphery of the wafer or the outer edge of the susceptor; A second heating device for heating the outer edge of the susceptor; and a control device that controls the second heating device based on the temperature during growth of an epitaxial film.

9. 9. The epitaxial wafer manufacturing apparatus according to claim 8, The epitaxial wafer manufacturing apparatus, wherein the second heating device is a laser heating device.

10. a first heating device for heating the wafer supported by the susceptor; a temperature measuring device for measuring the temperature of the outer periphery of the wafer or the outer edge of the susceptor; A second heating device for heating the outer periphery of the wafer; and a control device that controls the second heating device based on the temperature during growth of an epitaxial film.

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