Substrate processing apparatus, method of processing substrate, method of manufacturing semiconductor device, program and induction heating device

Abstract

To provide a technique that can reduce a temperature discrepancy in a zone boundary of induction heating.SOLUTION: There is provided a technique that includes (a) a process tube in which a substrate is accommodated and heat-treated; (b) a plurality of coils that are disposed along a longitudinal direction of the process tube and supplied with radio-frequency power from a power source; and (c) a controller configured to be capable of setting a phase difference between two adjacent coils, among the plurality of coils, to a predetermined value, wherein in (c1) the predetermined value is changeable and is set so as to make a temperature discrepancy occurring in a vicinity of a boundary between the two adjacent coils smaller than a temperature discrepancy when the phase difference is set to zero.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a substrate processing apparatus, a substrate processing method, a method for manufacturing a semiconductor device, a program, and an induction heating apparatus. [Background technology]

[0002] In semiconductor device manufacturing methods, vertical substrate processing equipment is sometimes used to form oxide films or anneal substrates (hereinafter referred to as wafers). When performing these processes on wafers, a processing gas is supplied into the processing chamber, and the interior of the processing chamber is induction-heated to a predetermined temperature using a magnetic coil. To maintain the predetermined temperature within the processing chamber, a temperature sensor, such as a thermocouple, may be installed within the processing chamber to detect the temperature. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-19081 Summary of the Invention [Problem to be solved by the invention]

[0004] When a processing chamber is divided into a plurality of induction heating zones and heated, temperature discrepancies may occur at the boundaries of the zones.

[0005] The present disclosure provides a technique capable of reducing temperature deviations at zone boundaries in induction heating. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, there is provided a technology comprising: (a) a processing tube that accommodates a substrate therein and performs heat processing; (b) a plurality of coils arranged along the longitudinal direction of the processing tube and supplied with high-frequency power from a power source; and (c) a control unit configured to be able to set a phase difference between two adjacent coils among the plurality of coils to a predetermined value, wherein (c1) the predetermined value is changeable and is set so as to make the temperature difference occurring near the boundary between the two adjacent coils smaller than when the phase difference is set to zero. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to reduce temperature deviations at the zone boundaries of induction heating. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a vertical cross-sectional view of a processing furnace according to one embodiment of the present disclosure. [Figure 2] FIG. 2 is a schematic configuration diagram of a control unit of a substrate processing apparatus according to one embodiment of the present disclosure. [Figure 3] FIG. 3 is a block diagram of a power supply circuit according to one embodiment of the present disclosure. [Figure 4] FIG. 4 is a diagram illustrating a temperature profile measuring method according to one embodiment of the present disclosure. [Figure 5] FIG. 5 is a diagram illustrating setting of a phase difference between drive voltages between coils according to one embodiment of the present disclosure. [Figure 6] FIG. 6 is a diagram illustrating an improvement in temperature ripple due to a phase difference according to one embodiment of the present disclosure. [Figure 7] FIG. 7 is a flow diagram of a substrate treatment according to one embodiment of the present disclosure. [Figure 8] FIG. 8 is a control flow diagram of the temperature increase process according to one embodiment of the present disclosure. [Figure 9] FIG. 9 is a diagram showing the temperature control results when power is reduced according to one embodiment of the present disclosure. [Figure 10] FIG. 10 is a diagram showing the temperature control results when there is no power reduction according to the comparative example. [Figure 11]FIG. 11 is a block diagram of a power supply device according to a modified example of the present disclosure. [Figure 12] FIG. 12 is a diagram illustrating synchronization of the inverter circuit of a power supply device according to a modified example of the present disclosure. [Figure 13] FIG. 13 is a flowchart illustrating a method for setting the reference phase of a power supply device according to a modified example of the present disclosure. [Figure 14] FIG. 14 is a perspective view of an induction heating device provided in addition to a substrate processing apparatus according to a modified example of the present disclosure. [Figure 15] FIG. 15 is a diagram illustrating a rack of an induction heating device according to a modified example of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, one embodiment of the present disclosure will be described mainly with reference to FIGS. 1 to 8. It should be noted that all drawings used in the following description are schematic, and the dimensional relationships between elements, the ratios of elements, etc. shown in the drawings do not necessarily correspond to the actual ones. Furthermore, the dimensional relationships between elements, the ratios of elements, etc. do not necessarily correspond between multiple drawings. Furthermore, in the drawings, substantially identical elements are denoted by the same reference numerals, and their description may be omitted. Furthermore, unless otherwise specified in the specification, each element is not limited to one, and multiple elements may be present.

[0010] (1) Configuration of the substrate processing equipment The substrate processing apparatus 1 is configured as a batch-type vertical annealing apparatus that performs annealing on multiple silicon carbide (SiC) substrates aligned vertically. By configuring it as a batch-type processing apparatus, it becomes possible to process many substrates at once, thereby improving productivity.

[0011] The substrate processing apparatus 1 has a processing furnace 2, and a boat 3 serving as a substrate holder is configured to be insertable and detachable into the processing furnace 2. The boat 3 is made of a heat-resistant material such as carbon graphite or SiC. The boat 3 is configured to hold a plurality of wafers 4 serving as substrates to be processed, each made of SiC or the like, stacked vertically in a horizontal position with their centers aligned.

[0012] A heat insulating part 5 made of a heat-resistant material such as SiC is disposed below the boat 3. The heat insulating part 5 supports the boat 3 from below and is configured to make it difficult for heat from a heating element 6 (described later) to be transmitted to the lower side of the processing furnace 2. The boat 3 loaded with a plurality of wafers 4 is carried into the processing furnace 2, whereupon heat treatment is performed.

[0013] 1, the processing furnace 2 is made of a heat-resistant material such as quartz or SiC, and includes a reaction tube 7 serving as a processing tube formed in a cylindrical shape with a closed upper end and an open lower end. A reaction chamber 8 serving as a processing chamber is formed in the hollow cylindrical portion of the reaction tube 7. The reaction chamber 8 is configured to accommodate the boat 3 described above, which holds wafers 4 serving as substrates to be processed and is made of SiC or the like.

[0014] A manifold 11 is disposed concentrically with the reaction tube 7 below the reaction tube 7. The manifold 11 is made of, for example, metal, and is formed in a cylindrical shape with open upper and lower ends. The manifold 11 is provided to support the reaction tube 7 from below. An O-ring (not shown) is provided as a sealing member between the manifold 11 and the reaction tube 7. The reaction tube 7 and the manifold 11 form a reaction vessel.

[0015] The process furnace 2 includes a heating element 6 as a heated body (susceptor) to be heated by induction heating, and induction coils 12 (12U, 12M, 12L) as an induction heating unit, i.e., a magnetic field generating unit. The induction coils 12 are arranged along the longitudinal direction of the reaction tube 7 and are configured as multiple induction coils including a first coil 12U as an upper coil, a second coil 12M as an intermediate coil, and a third coil 12L as a lower coil. The second coil 12M is provided outside the reaction tube 7 so as to surround the wafer 4 storage area. The second coil 12M is provided so as to surround the central portion of the wafer 4 storage area, excluding the upper and lower sides of the wafer 4 storage area. The first coil 12U is provided above the second coil 12M and outside the reaction tube 7. The third coil 12L is provided below the second coil 12M and outside the reaction tube 7 so as to surround the upper portion of the heat insulating unit 5. The reaction chamber 8 or the heating element 6 can be virtually divided into three longitudinally consecutive zones, namely, a first zone ZN1, a second zone ZN2, and a third zone ZN3, corresponding to the three induction coils. The second zone ZN2 corresponds to the area for accommodating the wafers 4 to be processed, and is an area where uniform heating is required.

[0016] The heating element 6 can be referred to as a susceptor. The heating element 6 is formed into a cylindrical shape using a conductive heat-resistant material such as carbon, and is provided so as to surround the boat 3 contained in the reaction chamber 8, i.e., so as to surround the area containing the wafers 4. The heating element 6 is formed into a cylindrical shape with open upper and lower ends, or a cylindrical shape with a closed upper end and an open lower end. The induction coil 12 is supported by a coil support 12a made of an insulating heat-resistant material, and is provided so as to surround the outer periphery of the reaction tube 7. In other words, the heating element 6 has a cylindrical configuration arranged approximately concentrically with the process tube 7.

[0017] When the pitch of the coil is defined as the interval between two adjacent single turns (windings) included in the coil, the pitch P12U of the coil winding of the first coil 12U is made narrower than the pitch P12M of the coil winding of the second coil 12M (P12U < P12M). Also, the pitch P12L of the coil winding of the third coil 12L is made narrower than the pitch P12M of the coil winding of the second coil 12M (P12L < P12M). Further, the plurality of coils (12U, 12M, 12L) are wound around the reaction tube 7 for each of the plurality of zones obtained by longitudinally dividing the reaction tube 7, and the space between two adjacent coils (between the first coil 12U and the second coil 12M, or between the second coil 12M and the third coil 12L) is wider than the respective pitches of the two coils. That is, the space between the first coil 12U and the second coil 12M is wider than the pitch P12U of the first coil 12U and the pitch P12M of the second coil 12M. Similarly, the space between the second coil 12M and the third coil 12L is wider than the pitch P12M of the second coil 12M and the pitch P12L of the third coil 12L. The plurality of induction coils (12U, 12M, 12L) include the first coil 12U, the second coil 12M, and the third coil 12L arranged in order in the longitudinal direction of the processing tube 7. The second coil 12M is formed such that the pitch of its winding is longer than the pitches (P12U, P12L) of the windings of the other coils (12U, 12L) and the pitch P12M of its winding is wider. The accommodation area of the wafer 4 as the area to be homogenized (also referred to as the homogenization area) of the processing tube 7 is set to protrude from both ends of the second coil 12M. Also, at least one of the plurality of induction coils (12U, 12M, 12L) is configured such that the length in the longitudinal direction of the processing tube 7 is larger than the diameter. With this configuration, it is possible to shorten the heating section necessary for obtaining a predetermined homogenization length, and reduce the equipment cost of the substrate processing apparatus 1, the operation cost of the substrate processing apparatus 1, and the power consumption.

[0018] The induction coils 12 (12U, 12M, 12L) are supplied with high-frequency power, for example, AC power of 10 to 450 kHz and 10 to 200 kW, from AC power sources 13 (13U, 13M, 13L) serving as power supply devices. The AC power sources 13 (13U, 13M, 13L) include a first AC power source 13U that supplies AC power to the first coil 12U, a second AC power source 13M that supplies AC power to the second coil 12M, and a third AC power source 13L that supplies AC power to the third coil 12L. The AC power source 13 is configured to be able to maintain a phase difference at a set predetermined value while controlling the power supplied to the multiple induction coils (12U, 12M, 12L) to a specified value. The AC power supply 13 is configured to be able to excite two adjacent coils (the first coil 12U and the second coil 12M, or the second coil 12M and the third coil 12L) among the multiple induction coils (12U, 12M, 12L) with waveforms having any phase difference within a predetermined range around a 180° phase difference, which is an opposite phase. For example, with the phase of AC power supplied to the second coil 12M by the second AC power supply 13M as a reference, the first AC power supply 13U can be set to shift the phase of the AC power supplied to the first coil 12U to the positive side by a phase difference within a predetermined range, and the third AC power supply 13L can be set to shift the phase of the AC power supplied to the third coil 12L to the negative side by a phase difference within a predetermined range.

[0019] The heating element 6 is provided at a position closer to the substrate 4 than the multiple induction coils (12U, 12M, 12L), and is induction heated by the multiple induction coils (12U, 12M, 12L). The heating element 6 is arranged over a longer range in the longitudinal direction of the process tube 7 than any of the multiple induction coils (12U, 12M, 12L).

[0020] An AC magnetic field generated by passing an AC current through the induction coil 12 induces an induced current in the heating element 6, which generates heat due to Joule heat. The heat generated by the heating element 6 heats the wafers 4 held in the boat 3 to a predetermined processing temperature, e.g., 1500°C to 2000°C, due to radiant heat emitted from the heating element 6. To prevent thermal damage, the temperature of the components below the processing furnace 2 is preferably maintained at, e.g., 200°C or less. A numerical range such as "1500°C to 2000°C" indicates that both the lower and upper limits are included within the range. For example, "1500°C to 2000°C" means "1500°C or higher and 2000°C or lower." In this specification, the processing temperature refers to the temperature of the wafers 4 or the temperature within the processing chamber 8, and the processing pressure refers to the pressure within the processing chamber 8. Furthermore, the processing time refers to the duration of the processing. These terms also apply to the following explanations.

[0021] Of the coils (first coil 12U, second coil 12M, third coil 12L) in the three zones (first zone ZN1, second zone ZN2, third zone ZN3), the coils on both sides (first coil 12U, third coil 12L) simulate the case where the central coil (second coil 12M) has infinite length, and are configured to heat more powerfully than the central coil (second coil 12M). In other words, the coils on both sides (first coil 12U, third coil 12L) are configured to have a higher magnetic flux density per unit area of ​​the heating element 6. That is, the coils on both sides (first coil 12U, third coil 12L) require a larger input power per unit length in the longitudinal direction (tube axis direction) of the process tube 7.

[0022] Consider a case where the pitch of each coil in the three zones (first coil 12U, second coil 12M, third coil 12L) is the same and the gaps between the coils (first coil 12U, second coil 12M, third coil 12L) are also the same pitch. In this case, the strong magnetic flux of the coils on both sides (first coil 12U, third coil 12L) penetrates deep into the central zone (second zone ZN2), making it impossible to control the temperature drop only near both ends of the central zone (second zone ZN2), making it difficult to uniformly heat the entire central zone (second zone ZN2).

[0023] Therefore, in the present disclosure, it is preferable that the gap between two adjacent coils (the first coil 12U and the second coil 12M, or the second coil 12M and the third coil 12L) be wider than the pitch of each of the two coils (the first coil 12U and the second coil 12M, or the second coil 12M and the third coil 12L). In particular, it is preferable that the length of the coil (the second coil 12M) in the central zone (the second zone ZN2) be shorter than that of the soaking zone (the area where the wafer 4 is accommodated), and that the gap between (the first coil 12U and the second coil 12M, or the second coil 12M and the third coil 12L) be located near both ends of the soaking zone (the area where the wafer 4 is accommodated).

[0024] A heat insulator 14 is provided between the reaction tube 7 and the heating element 6. The heat insulator 14 is formed in a cylindrical shape with a closed upper end and an open lower end.

[0025] A temperature sensor 15 for detecting the processing temperature is provided between the boat 3 holding the wafers 4 and the heating element 6. The temperature sensor 15 measures the temperature at three points corresponding to the top, middle, and bottom of the area where the wafers 4 are placed on the boat 3, and is electrically connected to a temperature controller 225 as a temperature control unit, as shown in FIG. 2. The temperature sensor 15 can be configured with multiple thermocouples housed in protective tubes that are attached vertically through the manifold 11. Specifically, three temperature measurement assemblies, each containing two thermocouples (one in use and one spare) housed in a protective tube, are installed corresponding to the three points. At least one of the temperature measurement assemblies extends to near the top of the boat 3. A radiation thermometer may be used as the temperature sensor 15.

[0026] The temperature regulator 225 controls the processing temperature of the wafer 4 to a desired temperature by adjusting the phase of the power or voltage supplied from the AC power supply 13 to the induction coil 12 based on the temperature information detected by the temperature sensor 15. The heating unit according to this embodiment is mainly composed of the heating element 6, the induction coil 12, the AC power supply 13, and the temperature sensor 15.

[0027] An outer heat insulating wall 16, for example, of a water-cooled structure, is provided outside the induction coil 12 to surround the reaction chamber 8 and suppress the transfer of heat from inside the reaction chamber 8 to the outside. Furthermore, a magnetic shield 17 is provided outside the outer heat insulating wall 16 to prevent the magnetic field generated by the induction coil 12 from leaking to the outside.

[0028] The processing furnace 2 is provided with a first gas nozzle 18 having a first gas supply port 18a at its upper end. The first gas nozzle 18 is disposed inside the heating element 6, vertically disposed between the wafer 4 accommodation area and the heating element 6. The first gas nozzle 18 is connected to a first gas supply pipe 19 provided to penetrate the manifold 11. A gas supply unit 21 is connected to the upstream end of the first gas supply pipe 19.

[0029] A second gas supply pipe 22 is disposed in the vertical direction outside the heating element 6, between the heat insulator 14 and the reaction tube 7. A second gas supply port 23 is provided at the downstream end of the second gas supply pipe 22. The second gas supply pipe 22 is disposed so as to penetrate the manifold 11. A gas supply unit 21 is connected to the upstream end of the second gas supply pipe 22.

[0030] A first exhaust port 24 is provided in the side wall of the manifold 11 facing the first gas supply port 18a, below the heat insulating unit 5, i.e., the wafer 4 accommodation area. A second exhaust port 25 is provided in the wall of the manifold 11 between the heat insulating body 14 and the reaction tube 7, on which the reaction tube 7 is mounted. The first exhaust port 24 and the second exhaust port 25 are connected to the upstream ends of branched exhaust pipes 26, respectively. The exhaust pipes 26 are provided with, in order from the upstream side, a pressure sensor 27 as a pressure detector, an APC (Auto Pressure Controller) valve 28 as a pressure regulator, and a vacuum pump 29 as a vacuum exhaust device. The pressure sensor 27, the APC valve 28, and the vacuum pump 29 are electrically connected to a pressure control unit (not shown). The pressure control unit controls the opening of the APC valve 28 based on pressure information measured by the pressure sensor 27, thereby maintaining the pressure in the reaction chamber 8 at a predetermined pressure.

[0031] Furthermore, by providing the second exhaust port 25 as described above, the purge gas, which is an inert gas such as nitrogen, supplied into the reaction chamber 8 from the second gas supply port 23 purges the space between the reaction tube 7 and the heat insulator 14 and is exhausted from the second exhaust port 25.

[0032] Furthermore, the boat 3 can be carried into the reaction chamber 8, i.e., boat loading, and carried out, i.e., boat unloading, by a lifting mechanism (not shown). By carrying the boat 3 into the reaction chamber 8, the opening of the processing furnace 2, i.e., the furnace port, is airtightly closed by a seal cap 31 via a sealing member such as an O-ring. Furthermore, the heat insulating part 5 can be rotatably supported by a boat support mechanism 30 provided on the seal cap 31.

[0033] The control unit 210 controls each unit (26, 27, 28, 29, 30, 225) of the substrate processing apparatus 1, and has a central processing unit (CPU) 212, a main memory device 216, and an auxiliary memory device 224, as described in Fig. 2. The auxiliary memory device 224 stores recipe information that defines a series of operations for causing the substrate processing apparatus 1 to perform an annealing process and the like, and a program that is executed by the CPU 212 to actually control the substrate processing apparatus 1 based on the recipe information. The auxiliary memory device 224 may include a recording medium such as an optical disk.

[0034] (Control unit) Fig. 2 is a schematic configuration diagram of a control unit of a substrate processing apparatus according to one embodiment of the present disclosure. As shown in Fig. 2, a controller 210, which is a control unit (control device, control means), is configured as a computer including a CPU (Central Processing Unit) 212, a RAM (Random Access Memory) 214, a storage device (main storage device) 216, and an I / O port 218. The RAM 214, the main storage device 216, and the I / O port 218 are configured to be able to exchange data with the CPU 212 via an internal bus 220. An input / output device 222 configured as, for example, a touch panel is connected to the controller 210.

[0035] The main memory device 216 is composed of, for example, a flash memory, an HDD (Hard Disk Drive), etc. The main memory device 216 readably stores a control program for controlling the operation of the substrate processing apparatus, a process recipe describing the procedure and conditions of an annealing (modification) process, etc. The process recipe is a combination of procedures in the substrate processing step (described later) that are executed by the controller 210 to obtain a predetermined result, and functions as a program. Hereinafter, the process recipe, the control program, etc. are collectively referred to simply as a program. The process recipe is also simply referred to as a recipe. In this specification, the term "program" may refer to a recipe alone, a control program alone, or both. The RAM 214 is configured as a memory area (work area) for temporarily storing programs, data, etc. read by the CPU 212.

[0036] The I / O port 218 is connected to the above-mentioned valve 28, pressure sensor 27, vacuum pump 29, boat support mechanism 30, temperature regulator 225, and the like.

[0037] The CPU 212 is configured to read and execute a control program from the main storage device 216, and to read a recipe from the main storage device 216 in response to an input of an operation command from the input / output device 222. The CPU 212 is configured to control the following control objects in accordance with the contents of the read recipe. The control objects include, for example, the pressure adjustment operation by the APC valve 28 based on the pressure sensor 27, the start and stop of the vacuum pump 29, the temperature adjustment operation by the temperature regulator 225 of the AC power supply 13 based on the temperature sensor 15, the rotation and rotation speed adjustment operation of the boat 3 by the boat support mechanism 30, or the lifting and lowering operation.

[0038] The controller 210 can be configured by installing the above-mentioned program stored in the external storage device 224 into a computer. The external storage device 224 is, for example, a magnetic disk such as a hard disk, an optical disk such as a CD, a magneto-optical disk such as an MO, a USB memory, an SSD, or other semiconductor memory. The main storage device 216 and the external storage device 224 are configured as computer-readable recording media. Hereinafter, these will be collectively referred to as recording media. When the term recording media is used in this specification, it may include only the main storage device 216, only the external storage device 224, or both. Note that the program may be provided to the computer using a communication means such as the Internet or a dedicated line, without using the external storage device 224.

[0039] The control unit 210 sets the target temperature for each zone (NE1, NE2, NE3) in the temperature regulator 225, and the temperature regulator 225 outputs power set values ​​122U, 122M, 122L, which are manipulated variables, to each of the AC power supplies 13 (13U, 13M, 13L) using PID control (proportional, integral, and derivative control), to bring the temperature of the thermocouples closer to the target temperature. In other words, the temperature regulator 225 outputs multiple manipulated variables (power set values ​​122U, 122M, 122L) that represent the power to be supplied to the multiple coils (first coil 12U, second coil 12M, and third coil 12L) so that the multiple temperature values ​​corresponding to the multiple heating zones (NE1, NE2, NE3) obtained from the multiple temperature sensors 15 approach the target values ​​of the corresponding target temperatures.

[0040] On the other hand, the fixed phase shift amounts (fixed phase amounts) 121U, 121M, and 121L are set directly by the control unit 210 for each of the AC power supplies 13 (13U, 13M, and 13L) without going through the temperature regulator 225. That is, the control unit 210 is configured to be able to set the phase difference between two adjacent coils (the phase difference between the first coil 12U and the second coil 12M, and the phase difference between the second coil 12M and the third coil 12L) among the multiple coils (the first coil 12U, the second coil 12M, and the third coil 12L) to a predetermined value using the fixed phase shift amounts 121U, 121M, and 121L. This predetermined value is changeable and is set so that the temperature difference occurring near the boundaries between the two adjacent coils (between the first coil 12U and the second coil 12M, and between the second coil 12M and the third coil 12L) is smaller than when the phase difference is set to zero. Here, "neighborhood" typically refers to an area smaller than each of the multiple heating zones, and in such an area, the temperature at the three temperature measurement points is controlled to match the target value, but the temperature error can become large as the area moves away from the three temperature measurement points.

[0041] The temperature regulator 225 may be configured as a part of the control unit 210, or may be provided separately from the control unit 210 as shown in FIG.

[0042] (power supply) Fig. 3 is a block diagram of a power supply device according to one embodiment of the present disclosure. Fig. 3 shows, as a representative example, the circuit configuration of first AC power supply 13U, which supplies AC power to first coil 12U, in AC power supplies 13 (13U, 13M, 13L) serving as the power supply device. The circuit configurations of second AC power supply 13M, which supplies AC power to second coil 12M, and third AC power supply 13L, which supplies AC power to third coil 12L, are the same as the circuit configuration of first AC power supply 13U, and therefore, for simplicity of the drawing, only the circuit configuration of first AC power supply 13U is depicted.

[0043] The first AC power supply 13U includes a phase shifter 101, a PWM (pulse width modulation) circuit 102, a bridge circuit 103, a matching circuit 104, low-pass filters LPF1 and LPF2, a power detector 105, a voltage detector 106, and a phase comparator 107.

[0044] The phase shifter 101 is configured to receive a signal from the oscillator 120 and change the phase or delay of the signal from the oscillator 120 so that the phase of the power supplied to the first coil 12U is adjusted by a fixed phase amount 121U. The output of the phase shifter 101 is supplied to the input of the PWM circuit 102.

[0045] The PWM circuit 102 generates first to third drive signals to be supplied to the bridge circuit 103 based on the output voltage of the phase shifter 101. The bridge circuit 103 includes transistors Tr1 and Tr3 having collector-emitter paths connected in series between a positive potential Vc and a negative potential Vg, and transistors Tr2 and Tr4 having collector-emitter paths connected in series between the positive potential Vc and the negative potential Vg.

[0046] The PWM circuit 102 is configured to be able to generate a first drive signal that turns on the transistors Tr1 and Tr4 of the bridge circuit 103, a second drive signal that turns on the transistors Tr2 and Tr3 of the bridge circuit 103, or a third drive signal that turns off all of the transistors Tr1-Tr4 of the bridge circuit 103.

[0047] The output signal of the bridge circuit 103 is supplied to the first coil 12U via a matching box 104 to control the driving of the first coil 12U.

[0048] The power of the output signal from bridge circuit 103 is detected by power detector 105, the detected output of power detector 105 is subtracted from power setting value 122U by subtractor 112, and the subtracted signal is input to PWM circuit 102 via low-pass filter LPF2. In this way, PWM circuit 102 is configured to drive first coil 12U with the desired power.

[0049] Furthermore, the output wiring of the matching box 104, to which the first coil 12U is connected, is connected to a voltage detector 106, which detects the output voltage of the matching box 104. The phase comparator 107 receives the output of the voltage detector 106 and a signal from the oscillator 120, and outputs a voltage or a numerical value corresponding to the phase difference between them. The subtractor 110 subtracts the phase comparison result of the phase comparator 107 from the fixed phase amount 121U. The subtraction result of the subtractor 110 is supplied to the phase shifter 101 via a low-pass filter LPF1. The phase shifter 101 is configured to shift the phase, for example, linearly, according to the voltage or numerical value output by the low-pass filter LPF1. This allows the phase of the voltage that drives the first coil 12U to be controlled so as to be locked in a desired state.

[0050] The second AC power supply 13M and the third AC power supply 13L are also configured so that the phase and power of the voltage that drives the second coil 12M and the third coil 12L can be controlled as desired using fixed phase amounts 121M, 121L and power setting values ​​122M, 122L.

[0051] The AC power supply 13 (13U, 13M, 13L) is configured to be able to electrically change predetermined values ​​as fixed phase amounts 121U, 121M, 121L by changing the phase difference of the voltages output corresponding to each of the multiple coils (12U, 12M, 12L).

[0052] As shown in FIG. 3, the first coil 12U, the second coil 12M, and the third coil 12L are wound in the same manner. In this example, when viewed from above, each coil (12U, 12M, 12L) is wound clockwise. The second coil 12M is configured so that the current flowing through it is input from the upper side of the second coil 12M and output from the lower side of the second coil 12M. The current flowing through the first coil 12U is configured so that the current flowing through it is input from the lower side of the first coil 12U and output from the upper side of the first coil 12U. The current flowing through the third coil 12L is configured so that the current flowing through the first coil 12U and the third coil 12L is input from the lower side of the third coil 12L and output from the upper side of the third coil 12L. The current flowing through the second coil 12M is used as the reference and the current flowing through the first coil 12U and the third coil 12L are configured to be in opposite phase. The coil pitch of each coil (12U, 12M, 12L) and the dimensions between each coil (12U, 12M, 12L) have been explained above, so a duplicate explanation will be omitted.

[0053] Here, if there is mutual induction between the coils (first coil 12U and second coil 12M, or second coil 12M and third coil 12L), power control will interfere with each other and become unstable. In the case of PWM drive control, where power control is performed by varying the on-period of transistors Tr1-Tr4 of bridge circuit 103, changing the power changes the voltage waveform, shifting the voltage phase and changing the degree of influence of mutual induction, making the control unstable.

[0054] In contrast, in the present disclosure, the voltage waveforms at both ends of the first coil 12U, the second coil 12M, and the third coil 12L are acquired by a voltage detector 106, and the phase difference of the driving voltage between the first coil 12U, the second coil 12M, and the third coil 12L is fixed as desired using fixed phase amounts 121U, 121M, and 121L, thereby solving the problem of unstable control.

[0055] Although the fixed phase shift amount has been described above as control of the voltage phase, it is not limited to this. The fixed phase shift amount is not limited to the voltage phase, and may be control of the current phase, power phase, or the like.

[0056] Next, a method for setting a phase difference according to one embodiment of the present disclosure will be described with reference to Figures 4 and 5. In the present disclosure, for example, the following procedures of step 1), step 2), and step 3) are repeatedly performed.

[0057] Step 1) While maintaining the reaction chamber 8 in a non-oxidizing atmosphere at approximately atmospheric pressure or reduced pressure, the temperature controller 225 heats the wafer 4 placement area to a predetermined temperature. At this time, fixed phase amounts 121U, 121M, and 121L are set using the temperature controller 225 under the control of the control unit 210. Then, a sheathed thermocouple 33 (described later) is inserted into the reaction tube 7, and the temperature measurement point is moved in the axial direction of the tube to measure the temperature profile of the entire wafer 4 placement area, including three temperature measurement points at the top, middle, and bottom of the wafer 4 placement area on the boat 3. The range of the temperature profile may include the insulating area in which the insulating unit 5 is located.

[0058] Step 2) In the temperature profile, evaluate whether the temperature ripple is within a predetermined value, and if so, end the procedure.

[0059] Step 3) The control unit 210 changes at least one of the fixed phase amounts 121U, 121M, and 121L to be given to the temperature regulator 225. The change can be performed by cut-and-try, or can be determined using, for example, a local search method such as a hill-climbing method or a genetic algorithm.

[0060] The above steps 1) to 3) are repeated until the temperature deviations at the top, middle, and bottom of the wafer 4 placement area of ​​the boat 3 are within a predetermined value. This makes it possible to reduce the temperature deviation at the zone boundaries of induction heating using the first coil 12U, second coil 12M, and third coil 12L by controlling the phase difference of the voltage that drives the induction coils (12U, 12M, 12L). In other words, the deviation (spatial variation) of the temperature near the zone boundaries from the target value can be reduced by directly controlling the voltage phase difference, thereby improving thermal uniformity.

[0061] 4 shows the installation of the temperature measurement assembly 34 used in step 1. As shown in FIG. 4, the manifold 11 has an annular flange portion 11a at its upper end that widens outward in the circumferential direction, and the reaction tube 7 is placed on the flange portion 11a. An O-ring 41 is provided between the reaction tube 7 and the flange portion 11a, and the O-ring 41 ensures airtightness between the reaction tube 7 and the flange portion 11a. The O-ring 41 and the flange portion 11a can be considered as part of a lid that closes the opening of the reaction tube (processing tube) 7.

[0062] Further, a TC port 42 for measuring a temperature profile is formed in the flange portion 11a. The TC port 42 has a cylindrical shape extending downward in parallel with the axis of the reaction tube 7, and the inner diameter of the lower end portion is enlarged and a thread portion 42a is formed on the outer periphery. The TC port 42 may have the same structure as the port to which the temperature sensor 15 is attached. A plug is inserted into the TC port 42 to airtightly close it except when the temperature profile is being measured.

[0063] The temperature measurement assembly 34 for measuring the temperature profile includes a sheathed thermocouple 33 and a protective tube 32 that protects the sheathed thermocouple 33. The sheathed thermocouple 33 includes a sheath tube and a thermocouple (TC) sealed within the sheath tube as a temperature measuring unit. The sheathed thermocouple 33 is bonded to the protective tube 32 near its lower end.

[0064] The sleeve 53 is cylindrical and fits loosely inside the TC port 42. The sleeve 53 has a large-diameter portion 53a and a small-diameter portion 53b that is smaller in diameter than the large-diameter portion 53a. The outer diameter of the large-diameter portion 53a is larger than the inner diameter of the TC port 42 above its lower end. The outer diameter of the small-diameter portion 53b is slightly smaller than the inner diameter of the TC port 42 above its lower end. The sleeve 53 is inserted from the lower end side of the TC port 42 with the small-diameter portion 53b facing up. Furthermore, a groove is formed around the inner wall of the large-diameter portion 53a, and an O-ring 54 is disposed therein as a first airtight member. An O-ring 55 as a second airtight member is disposed around the outer periphery of the lower end of the small-diameter portion 53b.

[0065] The cap nut 45 is threaded onto the threaded portion 42 a and compresses the O-ring 55 to form a seal between the TC port 42 and the sleeve 53 .

[0066] When the protective tube 32 is inserted into the sleeve 53, the O-ring 54 is pressed by the outer wall of the protective tube 32, and a certain degree of airtightness is achieved between the sleeve 53 and the protective tube 32. At this time, it is preferable that the O-ring 54 has a frictional force that is sufficient to prevent the temperature measuring assembly 34 from falling.

[0067] When measuring the temperature profile of the process furnace 2 using the temperature measurement assembly 34, the protective tube 32 is inserted into the sleeve 53, and the cap nut 45 is tightened to fix the sleeve 53. Then, while sliding the protective tube 32 relative to the O-ring 54, the temperature measurement assembly 34 is inserted and removed to change the position of the temperature measurement point by a predetermined amount, and the temperature detected by the thermocouple is recorded. By repeating this process, the temperature distribution in the tube axis direction can be measured. Alternatively, the protective tube 32 and the sleeve 53 may be formed integrally, eliminating the need for the O-ring 54. In this case, the protective tube 32 is airtightly fixed to the TC port 42 by tightening the cap nut 45. The sheathed thermocouple 33 is then inserted and removed from the protective tube 32 to change the position of the temperature measurement point. In other words, the sheathed thermocouple 33 is configured to be freely movable without being fixed to the protective tube 32. This method allows measurements to be taken in the process chamber 8 under the same reduced pressure as during actual processing.

[0068] FIG. 5 illustrates the fixed phase amount set in step 3). FIG. 5 shows an example of the drive voltages V12U, V12M, and V12L for the first coil 12U, the second coil 12M, and the third coil 12L. Here, the drive voltages V12U, V12M, and V12L have a frequency of, for example, 10 kHz and the same cycle CY1. The phase difference of the drive voltage V12U relative to the phase of the drive voltage V12M for the second coil 12M is defined as the first phase difference PD1, and the phase difference of the drive voltage V12L is defined as the second phase difference PD2. The first phase difference PD1 and the second phase difference PD2 can be controlled by adjusting the fixed phase amounts 121U and 121L relative to the fixed phase amount 121M. Here, the phase difference is defined based on the direction of the magnetic flux linkage of the coils, so the voltage waveforms of the first coil 12U and the third coil 12L, which are driven in opposite phases, are measured after being inverted again.

[0069] 6 is a diagram illustrating the temperature ripple improvement due to the phase difference according to one embodiment of the present disclosure, showing five examples of the phase difference (PD1, PD2) between the drive voltages of the first zone NZ1 and the third zone NZ3 relative to the phase of the drive voltage of the second zone NZ2.

[0070] The first example is (-108°, 108°), the second example is (-108°, 288°), the third example is (-108°, 36°), the fourth example is (-108°, 3.6°), and the fifth example is (-72°, 36°). As the first example is changed to the fifth example, the temperature drop between the first zone NE1 and the second zone NE2 is improved, and the temperature drop between the second zone NE2 and the third zone NE3 is also improved, improving heat generation efficiency. The amount of heat generated in the third zone NE3 is also reduced. In this way, the voltage phase difference can directly control and reduce or eliminate the deviation (spatial variation) of the temperature near the zone boundary from the target value. Thermal uniformity can also be improved.

[0071] (Substrate processing flow) Next, a substrate processing method (also referred to as a semiconductor device manufacturing method) using the above-described substrate processing apparatus 1 will be described with reference to the flowchart in Fig. 7. In this process, as one step in the semiconductor device manufacturing method, a SiC wafer 4 is annealed in a reaction chamber 8 in an argon (Ar) atmosphere. In this specification, the processing temperature refers to the temperature of the wafer 4 or the temperature of the reaction chamber 8, and the processing pressure refers to the pressure inside the reaction chamber 8. In the following description, the operation of each component of the substrate processing apparatus 1 is controlled by a controller 210.

[0072] (STEP:01) First, a plurality of wafers 4 are loaded (that is, charged) into the boat 3 that has been lowered outside the reaction chamber 8.

[0073] Next, the boat 3 is raised and loaded into the reaction chamber 8, and the wafers 4 are carried in (prepared). The lower opening of the reaction tube 7 is closed (i.e., sealed) with a seal cap 31. The reaction chamber 8 is then evacuated to a vacuum using a vacuum pump 29, after which Ar gas is supplied from the gas supply unit 21 and adjusted to a predetermined pressure using an APC valve 28. At this time, N2 gas is supplied into the temperature measurement assembly 15, which is a thermocouple, via a purge gas introduction pipe.

[0074] (STEP:02) Then, based on the temperature information detected by the thermocouple of the temperature measurement assembly 15, the AC power applied to the induction coil 12 is adjusted so that the wafer 4 reaches a predetermined processing temperature, thereby performing a temperature increase process to raise the temperature to the predetermined temperature at a predetermined temperature increase rate.

[0075] (STEP:03) Next, the wafer 4 is exposed to an Ar atmosphere at a predetermined temperature and pressure for a predetermined time, thereby activating the ion-implanted impurities or removing oxygen from the surface, thereby producing an annealed wafer.

[0076] Examples of processing conditions for activation annealing the wafer 4 include the following: processing temperature (wafer temperature): 1500°C to 1900°C, processing pressure (processing chamber pressure): 1 Pa to atmospheric pressure, Ar gas: 1 sccm to 5 SLM, N2 gas: 1 sccm to 5 SLM. By setting each processing condition within the respective range, the film formation process can proceed appropriately. Note that the notation of a numerical range such as "1500°C to 1900°C" above means that the lower and upper limits are included in the range. For example, "1500°C to 1900°C" means "1500°C or higher and 1900°C or lower." The same applies to other numerical ranges.

[0077] (STEP:04) Next, the AC power applied to the induction coil 12 is adjusted to perform a temperature-lowering process so that the wafer 4 is heated to a predetermined temperature at a predetermined temperature-lowering rate.

[0078] (STEP:05) Next, the APC valve 28 is closed to return the pressure inside the reaction chamber 8 to atmospheric pressure. After that, the seal cap 31 is lowered, and the boat 3 is removed (i.e., unloaded) from the reaction tube 7. After the boat 3 is removed, the wafers 4 are further cooled until they reach a temperature at which they can be transported. Finally, a transfer machine (not shown) stores the processed wafers 4 from the boat 3 into a cassette.

[0079] In addition, the control unit 210 may use fixed phase shift amounts 121U, 121M, 121L to give different phase differences to the first coil 12U, the second coil 12M, and the third coil 12L during temperature rise (STEP: 02), at a constant temperature during substrate processing after temperature rise (STEP: 03), and during temperature fall (STEP: 04).

[0080] (Control flow for temperature increase process) Next, the control flow in the temperature increase process will be described with reference to Fig. 8. Fig. 8 is a control flow diagram in the temperature increase process according to one embodiment of the present disclosure.

[0081] (STEP:11) The control unit 210 sets the current target temperature in the temperature regulator 225, which is a PID controller, according to a predetermined target temperature pattern (temperature increase rate).

[0082] (STEP:12) The temperature regulator 225 determines whether the temperature is in a predetermined section immediately before the maximum temperature of the target temperature pattern is reached (for example, whether the current temperature is between the maximum temperature -10°C and the maximum temperature).

[0083] (STEP:13) The temperature regulator 225 reduces the manipulated variables (power set values ​​122U, 122M, 122L) by multiplying them by a hard limit or a predetermined coefficient less than 1 if they are within a predetermined interval. In other words, for each of the multiple heating zones (NE1, NE2, NE3), the temperature regulator 225 reduces the corresponding manipulated variables (power set values ​​122U, 122M, 122L) in a predetermined interval immediately before the temperature value reaches the target value. The temperature regulator 225 also reduces the manipulated variables so as not to exceed the upper limit of the manipulated variables (power set values ​​122U, 122M, 122L) determined according to the target value.

[0084] (STEP:14) If the temperature is outside the predetermined range, the temperature regulator 225 cancels the reduction. The flow of repeating the above steps 11 to 14 is executed. By performing the above operations (steps 11 to 14), it is possible to suppress temperature overshoot (fluctuation over time) when the temperature transitions from rising to a constant temperature.

[0085] The hard limit (internal limit) is an operation to round off the PID calculation result by the power limit value, and is determined according to the target temperature. For example, if the power limit value is 80% and the PID calculation result is 95%, the values ​​of the power setting values ​​122U, 122M, and 122L are adjusted so that the heater output using the induction coil 12 is 80%.

[0086] 2, the case where the control unit 210 and the temperature regulator 225 are provided separately has been described, but the temperature regulator 225 may also be provided as part of the control unit 210. In this case, STEP:11 to STEP:14 are executed by the control unit 210.

[0087] Next, the results of temperature control will be described with reference to FIGS. 9 and 10. FIG. 9 is a diagram illustrating the results of temperature control with power reduction according to one embodiment of the present disclosure. FIG. 10 is a diagram illustrating the results of temperature control without power reduction according to a comparative example. In FIGS. 9 and 10, the first vertical axis on the left represents the temperature T (°C) detected by the thermocouple of the temperature measurement assembly 34, and the arrow TA indicates the target temperature value. The horizontal axis represents time (t). The second vertical axis on the right represents, for example, the current I (A) supplied to the first coil 12U of the induction coil 12, and the arrow IB indicates the power limit value. The target temperature value TA can be, for example, 1750°C. The target temperature value can be selected from the range of 1700°C to 1800°C.

[0088] 9 and 10, solid lines L80 and L90 indicate changes in the current supplied to the first coil 12U. Dotted lines L81 and L91 indicate the deviation of the temperature detected by the thermocouple of the temperature measurement assembly 34 from the target temperature value TA.

[0089] As shown in Figure 9, in the solid line L80, the current supplied to the first coil 12U is power-limited at the power limit value indicated by the arrow IB during the period PLM. Therefore, the temperature detected by the thermocouple indicated by the dotted line L81 is controlled so as not to exceed the target temperature value TA. In other words, the system is configured so that no overshoot occurs in the temperature when transitioning from a temperature rise to a constant temperature. Here, the period PLM is a predetermined section immediately before the maximum temperature of the target temperature pattern is reached.

[0090] 10, the current supplied to the first coil 12U is not power-limited at the power limit value indicated by the arrow IB during the period NPLM, as shown by the solid line L90. Therefore, the temperature detected by the thermocouple indicated by the dotted line L91 exceeds the target temperature value TA. In other words, a temperature overshoot OVSH occurs.

[0091] Although the above description has been given of a configuration for preventing overshoot, it can also be used for a configuration for preventing undershoot.

[0092] The configuration of the present disclosure (FIG. 9) can fully satisfy specifications such as, for example, limiting the overshoot to 2° C. or less with respect to the target temperature value TA (overshoot OVSH<2° C.).

[0093] (Modification of power supply device) Modifications of the present disclosure will be described mainly with reference to FIGS.

[0094] FIG. 11 is a block diagram of a power supply device according to a modified example of the present disclosure. The power supply device includes a first power supply device (hereinafter referred to as the first AC power supply) 13A, a second power supply device (hereinafter referred to as the second AC power supply) 13B, and a third power supply device (hereinafter referred to as the third AC power supply) 13C, which serve as high-frequency power supplies corresponding to coils 12M, 12U, and 12L. These AC power supplies can be collectively referred to as an induction heating device. In the following description, coil 12M will be referred to as the first coil, coil 12U as the second coil, and coil 12L as the third coil. FIG. 11 shows the circuit configurations of first AC power supply 13A and second AC power supply 13B as representative examples. The circuit configuration of third AC power supply 13C is the same as that of second AC power supply 13B, and is therefore not shown.

[0095] In the following description, the transistors (TT1, Tr1-Tr4) are described as bipolar transistors, and the on and off states of the bipolar transistors are controlled based on a drive signal (base drive signal) supplied to the base electrode, which serves as a control terminal. The transistors (TT1, Tr1-Tr4) may be MOSFETs (metal-oxide-semiconductor field-effect transistors) or IGBTs (insulated-gate bipolar transistors). In this case, the control terminal is the gate electrode, and the on and off states of the MOSFETs or IGBTs are controlled based on a drive signal (gate drive signal or gate signal) supplied to the gate electrode.

[0096] The first AC power supply 13A includes a first inverter power supply 310, a first oscillation control device 312, and a first matching box (also referred to as a matching section) 313. The first inverter power supply 310 includes a first rectifier circuit 315, a first step-down chopper circuit (first chopper circuit) 316, and a first inverter circuit 317. The first inverter circuit 317 corresponds to the bridge circuit 103 in FIG. 3.

[0097] The first oscillation control device 312 includes a first oscillation control circuit 321 and a first sensor 322. The first oscillation control circuit 321 includes a first chopper drive unit 324, a synchronization signal generation unit 325, and a first inverter drive unit (first drive unit) 326. The first inverter drive unit 326 corresponds to the PWM circuit 102 in FIG. 3.

[0098] The first rectifier circuit 315 rectifies the three-phase commercial power from the AC power supply 300 to provide DC power. The first rectifier circuit 315 is configured with a three-phase bridge diode rectifier as shown in FIG. 11. Three-phase bridge diode rectifiers are well known, so a description of their operation will be omitted. A first smoothing capacitor 390 is provided downstream of the first rectifier circuit 315 to absorb high-frequency components of the load current.

[0099] The first step-down chopper circuit 316, which can be described as a step-down regulator converter, receives the DC power output by the first rectifier circuit 315 and reduces the input voltage to generate an output voltage. The first step-down chopper circuit 316 converts the DC voltage output by the first rectifier circuit 315 to a predetermined voltage that is free of pulsations due to the commercial power frequency. The first step-down chopper circuit 316 is composed of a transistor TT1, a diode element, a coil LL1, and a capacitance element. The first step-down chopper circuit 316 stores energy in the coil LL1 when the transistor TT1 is on and releases the energy stored in the coil LL1 when the transistor TT1 is off. The longer the on-time of the transistor TT1, the higher the output voltage, and the shorter the on-time of the transistor TT1, the lower the output voltage.

[0100] The first inverter circuit 317 operates to inversely convert the DC power output from the first step-down chopper circuit 316 into high frequency power to be provided to the first coil 12M.

[0101] The first matching box 313 is a two-terminal pair circuit inserted between the first inverter circuit 317 and the first coil 12M, and it brings the load impedance of the first inverter circuit 317 close to a suitable value and provides DC insulation between the first inverter circuit 317 and the first coil 12M. The first matching box 313 can be a circuit that makes the input current and the output current in phase, and may include, for example, a transformer, a parallel capacitor provided to cancel the self-inductance of the primary and secondary windings of the transformer, and a series capacitor provided directly to either the primary or secondary winding.

[0102] The first sensor 322 detects the current or power output from the first inverter circuit 317 .

[0103] The first chopper drive unit 324 outputs an output signal to the base of the transistor TT1 of the first step-down chopper circuit 316, thereby feedback-controlling the output voltage of the first step-down chopper circuit 316, so that a control amount based on the current detected by the first sensor 322, etc., becomes a target value specified in the output current setting 800. The control amount is, for example, an effective value of the current. The first chopper drive unit 324 can be rephrased as a first feedback control unit, and is configured so that the output voltage of the first inverter circuit 317 can be changed by the first chopper drive unit 324 controlling the first step-down chopper circuit 316.

[0104] The first oscillation control circuit 321 oscillates a high-frequency signal at a predetermined frequency to generate a first clock signal of 100 MHz. For example, a temperature-compensated crystal oscillator with a frequency of 100 MHz may be provided, and the oscillated high-frequency signal may be used as the first clock as is.

[0105] The synchronization signal generating unit 325 also includes a frequency divider that divides the frequency of the first clock signal from the oscillator by a predetermined division ratio to generate a first high-frequency signal that is the drive frequency of the first coil 12M. The first high-frequency signal may be, for example, a high-frequency signal with a frequency of 10 kHz that is generated by dividing the frequency of the first clock signal by 1 / 10000.

[0106] The synchronization signal generating unit 325 is configured to be able to generate a synchronization signal SS that has a predetermined phase difference with respect to the first high-frequency signal and output it to the synchronization signal receiving unit 425. In other words, the synchronization signal generating unit 325 generates synchronization signals SS1 and SS2 that serve as references for the oscillation timing of the second AC power supply 13B and the third AC power supply 13C, respectively, and outputs the synchronization signals SS1 and SS2 to the synchronization signal receiving units 425 of the second AC power supply 13B and the third AC power supply 13C, respectively.

[0107] The synchronization signal generating unit 325 or the first inverter driving unit 326 includes a first counter (CUNT1) that counts the first clock signal. The synchronization signal generating unit 325 generates a synchronization signal SS (synchronization signals s1 and s3 with phases shifted by arbitrary set times ts1 and ts3: see FIG. 12) based on the count value of the first counter. The first counter is, for example, a programmable counter, and is cleared to 0 when the next clock is detected while the count value is 9999. The frequency divider of the synchronization signal generating unit 325 may be configured by the first counter.

[0108] The first inverter driving unit 326 is configured to generate a driving signal for the first inverter circuit 317 based on the first high-frequency signal generated by the synchronization signal generating unit 325. That is, the first inverter driving unit 326 may be configured to generate and output four output signals (driving signals) for the transistors Tr1-Tr4 of the first inverter circuit 317 based on the count value of the first counter (see FIG. 12). The driving signals are a base driving signal and a gate driving signal. Note that the first high-frequency signal may be any type of signal as long as it has frequency and phase information and can generate a driving signal for the first inverter circuit 317, and may be, for example, one or more specific count values ​​held by the first counter.

[0109] The second AC power supply 13B includes a second inverter power supply 410, a second oscillation control device 412, and a second matching device (also referred to as a matching section) 413. The second inverter power supply 410 includes a second rectifier circuit 415, a second step-down chopper circuit (second chopper circuit) 416, and a second inverter circuit 417. The second rectifier circuit 415, the second step-down chopper circuit 416, and the second inverter circuit 417 have the same configurations and functions as the first rectifier circuit 315, the first step-down chopper circuit 316, and the first inverter circuit 317, and therefore redundant explanations may be omitted.

[0110] The second oscillation control device 412 includes a second oscillation control circuit 421 and a second sensor 422. The second oscillation control circuit 421 includes a second chopper drive unit 424, a first synchronization signal receiving unit 425, and a second inverter drive unit (second drive unit) 426. The second inverter drive unit 426 corresponds to the PWM circuit 102 in FIG. 3. The second sensor 422, the second chopper drive unit 424, and the second inverter drive unit 426 have the same configurations and functions as the first sensor 322, the first chopper drive unit 324, and the first inverter drive unit 326, and therefore redundant explanations may be omitted.

[0111] The second rectifier circuit 415 rectifies the three-phase AC power from the AC power supply 300 to provide DC power.

[0112] A smoothing capacitor 490 is provided in the subsequent stage of the second rectifier circuit 415.

[0113] The second step-down chopper circuit 416 changes the voltage of the DC power output by the second rectifier circuit 415.

[0114] The second inverter circuit 417 operates to inversely convert the DC power output from the second step-down chopper circuit 416 into high-frequency power to be provided to the second coil 12U.

[0115] The second matching box 413 is inserted between the second inverter circuit 417 and the second coil 12U.

[0116] The second sensor 422 detects the current or power output from the second inverter circuit 417 .

[0117] The second chopper drive unit 424 outputs an output signal to the base of the transistor TT2 of the second step-down chopper circuit 416, thereby feedback-controlling the output voltage of the second step-down chopper circuit 416, so that a control amount based on the current detected by the second sensor 422 approaches a target value specified in the output current setting 800. The second chopper drive unit 424 can be rephrased as a second feedback control unit, and is configured so that the output voltage of the second inverter circuit 417 can be changed by the second chopper drive unit 424 controlling the second step-down chopper circuit 416.

[0118] The first synchronization signal receiving unit 425 receives the synchronization signal SS1 from the synchronization signal generating unit 325, and generates a second high frequency signal that has the same frequency as the first high frequency signal generated by the synchronization signal generating unit 325 and has a predetermined phase difference from the first high frequency signal. Note that the second high frequency signal may be the same as the synchronization signal SS1.

[0119] The second oscillation control device 412 or the synchronization signal receiving unit 425 may include a temperature compensated crystal oscillator similar to that of the first oscillation control device 312, or may receive the first clock signal from the first oscillation control device 312 to obtain a second clock signal synchronized with or having substantially the same frequency as the first clock signal. The second clock signal may be generated from a signal having a lower frequency than the first clock signal, such as the synchronization signal SS1 received from the synchronization signal generating unit 325, using a phase-locked loop (PLL) circuit, for example.

[0120] The second inverter driving unit 426 or the first synchronization signal receiving unit 425 includes a second counter (CUNT2) that counts the second clock signal and is reset by the synchronization signal SS. The second inverter driving unit 426 is configured to generate and output four output signals (drive signals) to the transistors Tr1-Tr4 of the second inverter circuit 417 based on the count value of the second counter (see FIG. 12).

[0121] The third AC power supply 13C includes a third inverter power supply, a third oscillation control device, and a third matching box 513 (also referred to as a matching unit). The third inverter power supply includes a third rectifier circuit, a third step-down chopper circuit, and a third inverter circuit. The third rectifier circuit, the third step-down chopper circuit, and the third inverter circuit have the same configurations and functions as the second rectifier circuit 415, the second step-down chopper circuit 416, and the second inverter circuit 417, and therefore redundant description will be omitted. The third AC power supply 13C has substantially the same configuration as the second AC power supply 13B, and supplies high-frequency power to the third coil 12L. The third matching box is inserted between the third AC power supply 13C and the third coil 12L.

[0122] The third oscillation control device includes a third oscillation control circuit and a third sensor. The third oscillation control circuit includes a third chopper drive unit, a second synchronization signal receiving unit, and a third inverter drive unit. The third sensor, the third chopper drive unit, the third inverter drive unit, and the second synchronization signal receiving unit have the same configurations and functions as the second sensor 422, the second chopper drive unit 424, the second inverter drive unit 426, and the first synchronization signal receiving unit 425, so redundant description will be omitted. As such, in this modification, the three power supply devices operate at the same fixed frequency. In other words, each power supply device does not perform tuning control to change the frequency according to the individual load impedance. This makes the induction heating device 13 stable in operation and easy to use.

[0123] Next, the synchronization of the first inverter circuit 317, the second inverter circuit 417, and the third inverter circuit 517 will be described with reference to FIG.

[0124] FIG. 12 schematically illustrates the count value of the first counter of the first AC power supply 13A, the drive signals of the four transistors Tr1-Tr4 of the first inverter circuit 317, the synchronization signal SS, the count value of the second counter of the second AC power supply 13B, the drive signals of the four transistors Tr1-Tr4 of the second inverter circuit 417, the count value of the third counter (CUNT3) of the third AC power supply 13C, and the drive signals of the four transistors Tr1-Tr4 of the third inverter circuit 517.

[0125] The first counter counts the first clock signal, which is the reference clock, and returns to 0 after counting for one cycle. The count value starts from 0, for example, and returns to 0 after 9999. The count value for 1 / 2 cycle is, for example, 4999. For example, when the frequency of the reference clock is 100 MHz, the cycle of the reference clock is 10 ns, and counting 10,000 times results in a cycle with a frequency of 10 kHz, that is, a cycle with a cycle period of 100 μs.

[0126] The synchronization signal SS output from the synchronization signal generating unit 325 of the first AC power supply 13A is received by the first and second synchronization signal receiving units (425) of the second AC power supply 13B and the third AC power supply 13C, and at that timing the count values ​​of the second counter and the third counter are reset to 0. The synchronization signal SS includes a synchronization signal s1 output to the first synchronization signal receiving unit 425 of the second AC power supply 13B and a synchronization signal s3 output to the second synchronization signal receiving unit of the third AC power supply 13C.

[0127] The synchronization signal generating unit 325 generates synchronization signals s1 and s3 with phases shifted by arbitrary set times ts1 and ts3 based on the count value of the first counter. For example, the set time ts1 is set as a delay time from the count value of 0, and the set time ts3 is set as the time until the count value becomes 0.

[0128] 12, the four drive signals for the four transistors Tr1-Tr4 of the first inverter circuit 317 are configured to be generated based on the count value of 0 of the first counter. Similarly, the four drive signals for the four transistors Tr1-Tr4 of the second inverter circuit 427 are generated based on the count value of 0 of the second counter, and the four drive signals for the four transistors Tr1-Tr4 of the third inverter circuit are generated based on the count value of 0 of the third counter.

[0129] Next, a method for setting the reference phases of the first AC power supply 13A, the second AC power supply 13B, and the third AC power supply 13C will be described with reference to Fig. 13. Fig. 13 is a flow chart illustrating a method for setting the reference phases of a power supply device according to a modification of the present disclosure.

[0130] (S100: LCR measurement) An LCR meter is used to sequentially measure the impedance (load impedance) seen from first AC power supply 13A, second AC power supply 13B, and third AC power supply 13C to each matching box 313, 413, and 513. During this measurement, the output of the power supply device not being measured is short-circuited. Using the equivalent series resistance obtained here, the active power contributing to induction heating can be calculated from the output current of each power supply device.

[0131] (S101: Impedance check) It is checked whether the impedance at 10 kHz measured in S100 is within a predetermined range. If it is within the predetermined range, proceed to S102. If it is not within the predetermined range, check the connections of the matching devices 313, 413, 513 and each coil (12M, 12U, 12L), and return to S100 to measure the impedance again.

[0132] (S102: Adjust the capacitor in the matching box) If the result does not fall within the predetermined range in S101, the ratings of the capacitors configured by series and parallel connections inside the matching devices 313, 413, and 513 of the first AC power supply 13A, the second AC power supply 13B, and the third AC power supply 13C are changed and the combination is redesigned to fall within the predetermined range in S101.

[0133] (S103: Power waveform measurement) The first AC power supply 13A, the second AC power supply 13B, and the third AC power supply 13C are actually operated to oscillate, and the oscillation waveforms are confirmed.

[0134] (S104: Phase adjustment) The phase difference is adjusted by comparing the measured waveforms. When the current phases of the first AC power supply 13A, the second AC power supply 13B, and the third AC power supply 13C are aligned during oscillation, that is, when the magnetic fields generated by each coil are combined in phase, the decrease in magnetic flux density at the coil boundaries is minimized, and this state is used as the reference. When the first AC power supply 13A, the second AC power supply 13B, and the third AC power supply 13C are oscillated simultaneously, the current in each coil is a combined current of the current from its own circuit power supply and the induced current from the other circuit power supplies. Therefore, even if the current waveforms during simultaneous oscillation are observed, it is extremely difficult to determine whether the current phases are aligned.

[0135] Therefore, data on the output voltage and current when the first AC power supply 13A, the second AC power supply 13B, and the third AC power supply 13C are oscillated individually is obtained, and the amount of voltage phase correction required to match the current phase is determined. Note that the voltage phase is defined based on the state in which the second AC power supply 13B and the third AC power supply 13C are in opposite phase to the first AC power supply 13A (i.e., the phase difference is 0 μs).

[0136] That is, the power supply is shorted for the non-excited coils (for example, the non-excited coils are the second coil 12U and the third coil 12L), and the voltage-current phase difference of the power supply output of the excited coils (for example, the excited coil is the first coil 12M) is measured, and the voltage phase difference that makes the currents in phase is determined as the reference phase. The combination of the non-excited coils and the excited coils is changed so that the excited coil is the first coil 12M, the second coil 12U, or the third coil 12L. When the first AC power supply 13A, the second AC power supply 13B, and the third AC power supply 13C are simultaneously oscillated using the reference phase obtained in this way, the currents are superimposed as when the coils are excited one by one, and the current phases of the first AC power supply 13A, the second AC power supply 13B, and the third AC power supply 13C are aligned.

[0137] When correcting deviations from the target temperature near the zone boundary, the voltage phase difference is further adjusted using this reference phase as a starting point. This method is superior to methods that directly control the current phase in that it does not require complex PID (Proportional-Integral-Differential) control based on the current phase, since it can maintain the current phase difference at a predetermined value simply by maintaining the voltage phase difference at a predetermined value, unless the load impedance fluctuates significantly.

[0138] Next, a perspective view of the induction heating device 13 provided in the substrate processing apparatus 1 will be described with reference to Fig. 14. Fig. 14 is a perspective view of the induction heating device provided in the substrate processing apparatus according to a modified example of the present disclosure. Fig. 15 is a diagram illustrating a rack of the induction heating device according to a modified example of the present disclosure.

[0139] 14, the substrate processing apparatus 1 has, in the front-rear direction Y, a main body 900 and a utility box 902 provided behind the main body 900 with a maintenance area 901 sandwiched therebetween. The utility box 902 includes, for example, a gas box, a power supply box, a controller box, and a valve box. The width L1 of the substrate processing apparatus 1 in the width direction X is, for example, approximately 850 to 1000 mm.

[0140] The induction heating device 13 is provided adjacent to the substrate processing apparatus 1. In the front-to-rear direction Y, the induction heating device 13 includes a first rack 910, a second rack 911 arranged behind the first rack 910 with a maintenance area 901 interposed therebetween, and a connecting portion 912 provided above the maintenance area 901 in the height direction Z. The connecting portion 912 is provided between the first rack 910 and the second rack 911, and has pipes, wiring, and the like installed therein. A width L2 of the induction heating device 13 in the width direction X is, for example, approximately 425 mm.

[0141] The height of the induction heating device 13 in the height direction Z is configured to be lower than the height of the substrate processing apparatus 1. Therefore, to prevent the induction heating device 13 from tipping over, the induction heating device 13 is fixed to the substrate processing apparatus 1 by L-shaped fixing brackets 920, 921, and 922 that serve as connecting brackets. The fixing brackets 920 and 921 are provided between the side of the main body 900 and the upper surface of the first rack 910. The fixing bracket 922 is provided between the upper surface of the second rack 911 and the side of the utility box 902. In this example, three fixing brackets 920, 921, and 922 are provided, but a single fixing bracket 920 may be used as long as it can prevent the induction heating device 13 from tipping over. In this way, the first rack 910 has a width that is less than half the width of the substrate processing apparatus 1 having the first coil 12M, the second coil 12U, and the third coil 12L, and is configured to be connected to the substrate processing apparatus 1 by fixing brackets 920, 921 so that the first rack 910 does not tip over and can be installed side by side.

[0142] In this way, induction heating device 13 is elongated in the height direction Z within a range not exceeding the substrate processing apparatus, and is divided into first rack 910 and second rack 911 in the front-rear direction Y so as to correspond to main body 900 and utility box 902. This makes it possible to prevent an increase in footprint when installed together with substrate processing apparatus 1.

[0143] 15, the first rack 910 has a first area 941, a second area 942, a third area 943, and a fourth area 944. The first area 941, the second area 942, and the third area 943 are arranged in this order from front to rear in the front-to-rear direction Y. The fourth area 944 is arranged above the first area 941, the second area 942, and the third area 943 in the height direction Z.

[0144] In the first region 941, the first inverter circuit 317 and the first inverter drive unit 326 of the first AC power supply 13A, the second inverter circuit 417 and the second inverter drive unit 426 of the second AC power supply 13B, and the third inverter circuit 517 and the third inverter drive unit 526 of the third power supply device are arranged in this order vertically in the height direction Z, with their respective longitudinal directions aligned in the front-to-rear direction. The first chopper drive unit 324, the second chopper drive unit 424, and the third chopper drive unit can be arranged vertically in the first region 941. The first oscillation control device 312, the second oscillation control device 412, and the third oscillation control device can also be arranged vertically in the first region 941.

[0145] A converter 600 is disposed behind the first inverter circuit 317 and first inverter drive unit 326, the second inverter circuit 417 and second inverter drive unit 426 of the second AC power supply 13B, and the third inverter circuit 517 and third inverter drive unit 526 of the third power supply device, which are arranged in the first region 941, i.e., in the second region 942. The converter 600 rectifies AC power and supplies it as DC power to the first AC power supply 13A, the second AC power supply 13B, and the third AC power supply 13C. The converter 600 includes or replaces the first rectifier circuit 315, the first smoothing capacitor 390, the second rectifier circuit 415, the second smoothing capacitor 490, the third rectifier circuit, and the third smoothing capacitor.

[0146] A power receiving board 610 is disposed behind the converter 600 disposed in the second area 942, that is, in the third area 943. The power receiving board 610 includes a no-fuse breaker, a terminal board, and the like to supply AC power 300.

[0147] In the fourth region 944 arranged above the first region 941, the second region 942 and the third region 943, that is, above the first inverter circuit 317 and the first inverter driving unit 326, the second inverter circuit 417 and the second inverter driving unit 426 of the second AC power supply 13B, the third inverter circuit 517 and the third inverter driving unit 526 of the third power supply device and the converter 600, the first matcher 313, the second matcher 413 and the third matcher 513 are arranged in the front-to-back direction in the longitudinal direction Y.

[0148] The second rack 911 has a cooling water system 930 arranged therein, which includes a cooling water system valve panel 931 and cooling water system piping 932. The cooling water system 930 is provided to supply cooling water for cooling the first AC power supply 13A, the second AC power supply 13B, and the third AC power supply 13C.

[0149] It should be noted that the present disclosure is not limited to the above-described embodiments, and various modifications are also included. For example, the above-described embodiments have been described in detail to clearly explain the present disclosure, and the present disclosure is not necessarily limited to those having all of the described configurations.

[0150] Furthermore, although the above-mentioned configurations, functions, and controllers serving as control units have been described mainly with reference to examples in which programs are created to realize some or all of them, it goes without saying that some or all of them may be realized in hardware, for example, by designing them as integrated circuits. That is, some or all of the functions of the processing unit may be realized by integrated circuits such as ASICs (Application Specific Integrated Circuits) and FPGAs (Field Programmable Gate Arrays) instead of programs.

[0151] In the above-described embodiment, an example of a batch-type substrate processing apparatus that processes multiple substrates at a time has been described. The present disclosure is not limited to the above-described embodiment and can be suitably applied to, for example, a single-wafer-type substrate processing apparatus that processes one or several substrates at a time. Furthermore, in the above-described embodiment, an example of forming a film using a substrate processing apparatus having a cold-wall processing furnace has been described. The present disclosure is not limited to the above-described embodiment and can be suitably applied to forming a film using a substrate processing apparatus having a hot-wall processing furnace. [Explanation of symbols]

[0152] 1: substrate processing equipment, 7: Processing tube (reaction tube), 12, 12U, 12M, 12L: induction coil, 13: AC power supply 210: control unit, 225: Temperature controller.

Claims

1. (a) a processing tube for accommodating a substrate therein and performing a heat treatment; (b) a plurality of coils arranged along the longitudinal direction of the processing tube and supplied with high-frequency power from a power source; (c) a control unit configured to be able to set a phase difference between two adjacent coils among the plurality of coils to a predetermined value; (c1) A substrate processing apparatus, wherein the predetermined value is variable and set so as to reduce the temperature difference occurring near the boundary between the two adjacent coils to a value smaller than when the phase difference is set to zero.

2. 2. The substrate processing apparatus according to claim 1, wherein the power supply is configured to be able to maintain the phase difference at the set predetermined value while controlling the power supplied to the plurality of coils to a designated value.

3. The substrate processing apparatus according to claim 1 , wherein the control unit is configured to be able to set the predetermined value to different values ​​during temperature rise and during a constant temperature period after the temperature rise.

4. 3. The substrate processing apparatus according to claim 2, wherein the power supply is configured to excite two adjacent coils of the plurality of coils with waveforms having any phase difference within a predetermined range before and after a phase difference of 180°, which is an opposite phase, as a reference.

5. The substrate processing apparatus according to claim 2 , wherein the power supply is configured to electrically change the predetermined value by changing a phase difference between voltages outputted to the plurality of coils.

6. The substrate processing apparatus according to claim 1 , wherein the phase difference is a phase difference between voltages.

7. a protective tube disposed inside the process tube, communicating with the outside of the process tube and providing a space that allows movement of a temperature sensor in the longitudinal direction of the process tube; The substrate processing apparatus according to claim 1 , further comprising: a port provided in a lid that closes the opening of the processing tube, the port connecting the lid and the protection tube substantially airtightly.

8. the plurality of coils are wound around the treatment tube for each of a plurality of zones obtained by dividing the treatment tube in the longitudinal direction; The substrate processing apparatus according to claim 1 , wherein the distance between two adjacent coils of the plurality of coils is wider than the pitch between the two adjacent coils.

9. a heating element provided at a position closer to the substrate than the plurality of coils and inductively heated by the coils; The substrate processing apparatus according to claim 6 , wherein the heating element is disposed over a longer range in the longitudinal direction of the processing tube than any of the plurality of coils.

10. The substrate processing apparatus according to claim 1 , wherein at least one of the plurality of coils has a length in the longitudinal direction of the processing tube that is greater than a diameter thereof.

11. the plurality of coils include a first coil, a second coil, and a third coil arranged in order in the longitudinal direction of the processing tube; the second coil is longer than the first coil and the third coil, and the pitch of the second coil is wider than the pitch of the first coil and the third coil; The substrate processing apparatus according to claim 1 , wherein the region of the processing tube to be uniformly heated is set to extend beyond both ends of the second coil.

12. (e) a plurality of temperature sensors obtaining temperature values ​​corresponding to a plurality of heating zones; (f) a temperature regulator configured to output a plurality of manipulated variables representing power to be supplied to the plurality of coils so that the values ​​of the plurality of temperatures approach corresponding target values; (f1) The substrate processing apparatus according to claim 1, wherein the temperature regulator reduces the corresponding manipulated variable for each of the plurality of heating zones in a predetermined section immediately before the temperature value reaches the target value.

13. The substrate processing apparatus according to claim 12 , wherein the temperature regulator reduces the manipulated variable so that the manipulated variable does not exceed an upper limit value determined based on the target value.

14. The substrate processing apparatus according to claim 13 , wherein the temperature controller reduces the manipulated variable by multiplying the manipulated variable by a predetermined coefficient less than one.

15. (a) a processing tube for accommodating a substrate therein and performing a heat treatment; (b) a cylindrical susceptor disposed approximately concentrically with the processing tube; (c) a plurality of coils for induction heating a plurality of heating zones that are set by dividing the susceptor into a plurality of zones in the tube axis direction; (d) a plurality of temperature sensors obtaining temperature values ​​corresponding to the plurality of heating zones; (e) a control unit configured to output a plurality of manipulated variables representing powers to be supplied to the plurality of coils so that the values ​​of the plurality of temperatures approach corresponding target values; (c1) A substrate processing apparatus, wherein the plurality of coils include a first coil, a second coil, and a third coil arranged in order in the longitudinal direction of the processing tube, the second coil being longer than the first coil and the third coil and having a wider pitch, and a soaking area in which a substrate to be processed is placed being set to extend beyond both ends of the second coil.

16. (a) a substrate processing apparatus including a process tube for accommodating a substrate therein and performing a heat treatment thereon, a plurality of coils arranged along the longitudinal direction of the process tube and supplied with high frequency power from a power source, and a control unit configured to be able to set a phase difference between two adjacent coils among the plurality of coils to a predetermined value, the process comprising: supplying high frequency power to the plurality of coils arranged along the longitudinal direction of the process tube, thereby raising the temperature of the substrate accommodated inside the process tube; (b) heat treating the substrate at a controlled temperature; (c) A substrate processing method, wherein in at least one of the heating step and the heat treatment step, a phase difference between two adjacent coils among the plurality of coils is set so that the temperature deviation occurring near the boundary between the two adjacent coils is smaller than when the phase difference is zero.

17. (a) a substrate processing apparatus including a process tube for accommodating a substrate therein and performing a heat treatment thereon, a plurality of coils arranged along the longitudinal direction of the process tube and supplied with high frequency power from a power source, and a control unit configured to be able to set a phase difference between two adjacent coils among the plurality of coils to a predetermined value, the process comprising: supplying high frequency power to the plurality of coils arranged along the longitudinal direction of the process tube, thereby raising the temperature of the substrate accommodated inside the process tube; (b) heat treating the substrate at a controlled temperature; (c) In at least one of the heating process and the heat treatment process, a phase difference between two adjacent coils among the plurality of coils is set so that the temperature difference occurring near the boundary between the two adjacent coils is smaller than when the phase difference is set to zero.

18. (a) a substrate processing apparatus including a process tube for accommodating a substrate therein and performing a heat treatment thereon, a plurality of coils arranged along a longitudinal direction of the process tube and supplied with high frequency power from a power source, and a control unit configured to be able to set a phase difference between two adjacent coils among the plurality of coils to a predetermined value, the process comprising: supplying high frequency power to the plurality of coils arranged along a longitudinal direction of the process tube, thereby raising the temperature of the substrate accommodated inside the process tube; (b) heat treating the substrate at a controlled temperature; (c) A program in which, in at least one of the temperature increasing procedure and the heat treatment procedure, the phase difference between two adjacent coils among the plurality of coils is set so that the temperature difference occurring near the boundary between the two adjacent coils is smaller than when the phase difference is set to zero.

19. (a1) a first inverter circuit that inversely converts DC power into high-frequency power that is provided to a first coil; (b1) a first power supply device including a first oscillation control device having a synchronization signal generating unit that oscillates a high frequency signal of a predetermined frequency and generates a synchronization signal, and a first drive unit that generates a drive signal for the first inverter circuit based on the first high frequency signal oscillated by the synchronization signal generating unit; (a2) a second inverter circuit that inversely converts the DC power into high-frequency power that is provided to the second coil; (b2) a second power supply device including a second oscillation control device having a synchronization signal receiving unit that receives the synchronization signal from the first oscillation control device and generates a second high-frequency signal that has the same frequency as the first high-frequency signal but has a predetermined phase difference, and a second drive unit that generates a drive signal for the second inverter circuit based on the second high-frequency signal; An induction heating device comprising:

20. The first power supply device (c1) a first sensor that detects the current or power output from the first inverter circuit as a control amount; (d1) a first feedback control unit configured to be able to change the output voltage of the first inverter circuit and to control the output voltage so that a control amount detected by the first sensor approaches a specified target value; The second power supply device (c2) a second sensor that detects the current or power output from the second inverter circuit as a control amount; (d2) a second feedback control unit configured to be able to change the output voltage of the second inverter circuit and to control the output voltage so that the control amount detected by the second sensor approaches a specified target value.

21. The first power supply device (c1) a first rectifier circuit that rectifies an AC power source to provide DC power; (d1) a first chopper circuit that changes the voltage of the DC power output by the first rectifier circuit; (e1) a sensor that detects the current or power output from the first inverter circuit as a control amount; (f1) a first chopper drive unit that feedback controls the output voltage of the first chopper circuit so that the detected control amount approaches a specified target value; The second power supply device (c2) a second rectifier circuit that rectifies the AC power source to provide DC power; (d2) a second chopper circuit that changes the voltage of the DC power output by the second rectifier circuit; (e2) a sensor that detects the current or power output from the second inverter circuit as a control amount; (f1) a second chopper drive unit that feedback-controls the output voltage of the second chopper circuit so that the detected controlled variable approaches a specified target value.

22. a first matching box inserted between the first inverter circuit and the first coil; 21. The induction heating device according to claim 19, further comprising: a second matching box inserted between the second inverter circuit and the second coil.

23. a third power supply unit having substantially the same configuration as the second power supply unit and supplying high frequency power to a third coil; 21. The induction heating device according to claim 19, further comprising: a third matching box inserted between the third power supply device and the third coil.

24. the synchronization signal generating unit is configured to generate the synchronization signal having the predetermined phase difference with respect to the first high frequency signal and output the synchronization signal to the synchronization signal receiving unit; the synchronization signal receiving unit oscillates the second high frequency signal based on the timing of the synchronization signal; The induction heating device according to any one of claims 19 to 21, wherein the frequency of the first high frequency signal is fixed during operation.

25. the synchronization signal generating unit includes a first counter that counts a first clock signal having a frequency higher than that of the first high frequency signal; the first driving unit generates a driving signal for the first inverter circuit, including four gate signals, based on the count value of the first counter; the synchronization signal receiving unit includes a second counter that counts a second clock signal having substantially the same frequency as the first clock signal and is reset by the synchronization signal; 25. The induction heating device according to claim 24, wherein the second driving unit generates a driving signal for the second inverter circuit including four gate signals based on the count value of the second counter.

26. the first to third power supply devices are arranged in a vertical direction such that their longitudinal directions are in a front-to-rear direction; a converter is disposed behind the first to third power supply devices that rectifies AC power and supplies the DC power to the third to third power supply devices; the first to third matching boxes are arranged in a front-to-rear direction above the first to third power supply devices and the converter; 24. The induction heating device according to claim 23, further comprising a first rack for placing a power receiving board behind the converter.

27. 27. The induction heating apparatus according to claim 26, further comprising a second rack disposed behind the first rack with a maintenance area therebetween, the second rack having a cooling water system disposed therein.

28. 27. The induction heating device of claim 26, wherein the first rack has a width less than half the width of the substrate processing device having the first to third coils, and is configured to be connected to the substrate processing device and be arranged side by side so as not to tip over.

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