Substrate processing apparatus and substrate processing method

Abstract

To allow stricter control to be performed in substrate processing that requires applying an AC voltage to a load portion.SOLUTION: A substrate processing apparatus of the present invention includes an on signal generating unit 22 that periodically outputs an on signal, and a relay control unit 23 that, when an on signal having a temporal length shorter than a half-wave time is input, does not pass the on signal to a solid-state relay 24, extends an on signal input at the next time by the temporal length of the on signal that was not passed, and generates an extended on signal whose temporal length is longer than the half-wave time to transmit it to the solid-state relay 24.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a substrate processing apparatus and a substrate processing method for performing a predetermined process on a substrate. [Background technology]

[0002] Patent Document 1 describes a substrate processing apparatus in which an upper plate on which a substrate is placed is cooled or heated by a heat treatment unit, and the temperature of the heat treatment unit is adjusted by a temperature adjustment unit. This substrate processing apparatus detects the temperature of the upper plate and maintains the temperature of the upper plate at a set value based on the detected temperature. When a control value required for this temperature adjustment is less than a second threshold, the upper plate is feedback-controlled based on the control value. On the other hand, when the control value required for temperature adjustment is equal to or greater than a first threshold, the upper plate is feedforward-controlled based on a value higher than the control value. This configuration, which switches between feedback control and feedforward control, improves temperature responsiveness while preventing large overshoots and undershoots. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-183815 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional control, the configuration for applying an AC voltage to a load has not been fully optimized. For example, when controlling temperature using an AC voltage, a solid-state relay is used that applies an AC voltage to a load during an ON signal. Some such solid-state relays have a zero-cross function. The zero-cross function can suppress the generation of inrush current and radiated noise when the solid-state relay receives an ON signal.

[0005] In cases where precise temperature control is required, the control period is set to a short value. In such cases, the length of the ON signal over time may be shorter than the half-wave time, which is half the cycle of the AC voltage. For the zero-cross function to operate, the ON signal must be input to the solid-state relay when the AC voltage reaches 0V. However, if the length of the ON signal over time is shorter than the half-wave time, the ON signal may disappear before the AC voltage reaches 0V, and the zero-cross function may not operate. In such a situation, the temperature control will be performed while the ON signal is ignored, making precise temperature control difficult.

[0006] The present invention has been made in view of the above circumstances, and has as its object to provide a substrate processing apparatus that can operate under strict control, and a substrate processing method that allows for strict control. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention has the following configuration. That is, the substrate processing apparatus of the present invention includes a load section to which an AC voltage is applied, a solid-state relay having a zero-cross function that starts applying an AC voltage to the load section when the AC voltage becomes 0 V upon input of an ON signal; an ON signal generating unit that outputs the ON signal for each control period; a control unit that is interposed between the output of the on signal generating unit and the input of the solid-state relay, and that, when an on signal that is equal to or longer in time than a half-wave time, which is half the cycle of an AC voltage, is input, passes the on signal to the solid-state relay, and, when an on signal that is shorter in time than the half-wave time is input, does not pass the on signal to the solid-state relay, and extends the next input on signal by the length in time of the on signal that was not passed, and generates an extended on signal whose length in time is longer than the half-wave time and transmits it to the solid-state relay. It is characterized by the following.

[0008] [Operations and Effects] The above-described configuration includes an ON signal generator that periodically outputs ON signals, and a control unit that, when an ON signal shorter than the half-wave time is input, does not pass the ON signal to the solid-state relay and extends the next ON signal input by the same amount as the ON signal that was not passed, generating an extended ON signal whose length over time is longer than the half-wave time and transmitting it to the solid-state relay. ON signals shorter than the half-wave time generated by the ON signal generator are combined and extended, and are reflected in the control of the solid-state relay with zero-crossing function. This is because the length over time of the extended ON signal is longer than the half-wave time, and there will always be a point during the life of the extended ON signal where the AC voltage becomes 0V. This configuration prevents the generation of ignored ON signals, enabling more precise operation control of the load unit.

[0009] In the above-described substrate processing apparatus, A sensor, a calculation unit that calculates an availability rate, which is a time rate at which power is supplied to the load unit within the control period, based on an output of the sensor, It is preferable that the ON signal generating section performs feedback control to input the ON signal to the control section in a time-dependent length corresponding to the operation rate.

[0010] [Operation and Effect] According to the above-mentioned configuration, the sensor and the calculation unit that calculates the operation rate of the load unit based on the output of the sensor are provided, and the ON signal generation unit performs feedback control by inputting the ON signal to the control unit with a time-dependent length that corresponds to the operation rate. With this configuration, it is easy to generate the ON signal required to control the load unit.

[0011] In the above-described substrate processing apparatus, the length of the ON signal generated by the ON signal generating unit is discrete and is an integer multiple of a predetermined unit time; The control unit accumulating the operation rates calculated by the calculation unit for each control period; The accumulated operating rate is converted into the time length of the ON signal to obtain a continuous converted time; setting a reference time point at which the converted time is equal to or exceeds the half-wave time; generating the extension-on signal by additionally extending at least the unit time at the reference time point; It is preferable that the excess operating time obtained by subtracting the converted time at the reference time from the time length of the extended on signal transmitted to the solid-state relay at the reference time is subtracted from the converted time when determining the next reference time.

[0012] [Operation and Effect] According to the above-described configuration, the control unit accumulates the load unit's operating rate calculated by the calculation unit for each control cycle, converts the accumulated operating rate into the time length of the ON signal to obtain the converted time, sets a reference point at which the converted time is equal to or exceeds a half-wave time, and generates an extended ON signal by additionally extending at least a predetermined unit time at the reference point. With this configuration, it is possible to improve the responsiveness of control even if the time length of the ON signal generated by the ON signal generation unit is discrete and is a predetermined integer multiple.

[0013] Furthermore, according to the above-described configuration, the control unit subtracts the excess operation time, which is obtained by subtracting the converted time at the reference time from the length over time of the extended ON signal transmitted to the solid-state relay at the reference time, from the converted time when determining the next reference time. This configuration makes it possible to improve the responsiveness of the control and suppress excessive operation of the load unit.

[0014] In the above-described substrate processing apparatus, Preferably, the control unit generates the extension-on signal by additionally extending at least the unit time at the reference time point before the reference time point is reached, and transmits the extension-on signal to the solid-state relay.

[0015] [Operation and Effect] According to the above-mentioned configuration, the control unit transmits the extended ON signal to the solid-state relay before the time when the length of the extended ON signal exceeds a half-wave time. This configuration allows the load unit to operate earlier than the time when the extended ON signal is actually required. This further improves the responsiveness of the solid-state relay with zero-crossing function.

[0016] In the above-described substrate processing apparatus, The sensor is preferably a temperature sensor that detects temperature.

[0017] [Operation and Effect] According to the above-mentioned configuration, the sensor is a temperature sensor that detects temperature. In this way, the present invention can be used for temperature regulation control.

[0018] In the above-described substrate processing apparatus, Preferably, the control unit generates the extended ON signal by cumulatively extending the input ON signal by the time lengths of the multiple ON signals that were not passed.

[0019] [Operation and Effect] According to the above-mentioned configuration, the control unit generates an extended ON signal by cumulatively extending the input ON signal by the time length of the multiple ON signals that were not passed. By merging three or more ON signals to generate an extended ON signal in this way, even if there is an ON signal that is significantly shorter in time than the half-wave time, it can be reflected in the control of the load unit without being overlooked.

[0020] In order to solve the above problems, the present invention has the following configuration. That is, the substrate processing method of the present invention is a substrate processing method in a substrate processing apparatus including: a load unit to which an AC voltage is applied; a solid-state relay having a zero-cross function that starts applying an AC voltage to the load unit when the AC voltage becomes 0 V upon input of an ON signal; and an ON signal generation unit that periodically outputs the ON signal, a comparison step of comparing the time length of the ON signal with a half-wave time, which is half the period of an AC voltage; an extended ON signal generating step of merging a plurality of ON signals to generate an extended ON signal having a temporal length equal to or longer than the half wave time when the temporal length of the ON signal is less than the half wave time; a voltage control step of controlling an AC voltage applied to the load section based on the on signal or the extended on signal. It is characterized by the following.

[0021] [Operation and Effect] The above-mentioned configuration includes a comparison step of comparing the length of the ON signal over time with a half-wave time, which is half the cycle of the AC voltage, an extended ON signal generation step of merging multiple ON signals over time to generate an extended ON signal whose length over time is equal to or greater than the half-wave time when the length of the ON signal over time is less than the half-wave time, and a voltage control step of controlling the ON signal or the AC voltage applied to the load unit based on the extended ON signal. With this configuration, no ignored ON signals are generated, allowing for more precise operation control of the load unit. [Effects of the Invention]

[0022] The substrate processing apparatus and substrate processing method of the present invention enable more precise control during substrate processing that requires application of an AC voltage to a load section. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a plan view illustrating an overall configuration of a substrate processing apparatus according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view illustrating the configuration of a heat treatment chamber according to an embodiment. [Figure 3] FIG. 3 is a functional block diagram illustrating heater control according to the embodiment. [Figure 4] 4A to 4C are waveform diagrams illustrating functions of a solid state relay according to an embodiment. [Figure 5] 5A and 5B are waveform diagrams illustrating the operation of a relay control unit according to the embodiment. [Figure 6] 5A and 5B are waveform diagrams illustrating the operation of a relay control unit according to the embodiment. [Figure 7] 1 is a flowchart illustrating substrate processing according to an embodiment. [Figure 8] 4 is a flowchart illustrating heater control according to the embodiment. [Figure 9] FIG. 10 is a waveform diagram illustrating the effect according to the embodiment. [Figure 10] FIG. 10 is a conceptual diagram illustrating a configuration according to one modified example of the present invention. [Figure 11] FIG. 10 is a conceptual diagram illustrating a configuration according to one modified example of the present invention. [Figure 12] FIG. 10 is a conceptual diagram illustrating a configuration according to one modified example of the present invention. [Figure 13] FIG. 10 is a conceptual diagram illustrating a configuration according to one modified example of the present invention. [Figure 14] FIG. 10 is a conceptual diagram illustrating a configuration according to one modified example of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] An embodiment of the present invention will be described below with reference to the drawings. The photolithography apparatus of the embodiment includes a stepper that performs exposure processing when creating a device on the surface of a substrate, and a substrate processing apparatus that performs necessary substrate processing before and after the exposure processing. The substrate processing apparatus has a thermal processing unit controlled by the present invention. [Example]

[0025] 1. Overall structure FIG. 1 is a plan view showing the overall configuration of the photolithography apparatus of this example. The photolithography apparatus of this example has a structure in which a substrate processing apparatus 1 and a stepper 2 are connected. The substrate processing apparatus 1 further has an indexer block 3, a coater block 5, a developer block 7, and an interface block 9. The indexer block 3, the coater block 5, the developer block 7, and the interface block 9 are arranged in this order to form the substrate processing apparatus 1. The substrate processing apparatus 1 has a housing 1A that houses each block. The housing 1A has a substantially rectangular shape in a plan view. A load port 11 is provided to protrude from the wall surface at one end of the housing 1A.

[0026] For convenience, in this specification, the direction in which the indexer block 3, coater block 5, developer block 7, and interface block 9 in the substrate processing apparatus 1 are arranged is referred to as the front-to-rear direction (X direction). The X direction extends horizontally. The direction from the coater block 5 to the indexer block 3 in the substrate processing apparatus 1 is referred to as the front. The direction opposite to the front is referred to as the rear. The horizontal direction perpendicular to the X direction is referred to as the left-to-right direction (Y direction). The Y direction is also the direction in which multiple load ports 11 are arranged. For convenience, one side of the Y direction is referred to as the right, and the opposite side of the right is referred to as the left. The height direction (Z direction) is perpendicular to both the X direction and the Y direction and coincides with the vertical direction. In each figure, front, back, right, left, top, and bottom are indicated as appropriate for reference.

[0027] 2. Indexer Block 1, the indexer block 3 includes a load port 11, which is an entrance through which a carrier C, which stores multiple substrates W in a horizontal position at predetermined intervals in the Z direction, is introduced into the block. The carrier C can be placed on the load port 11.

[0028] A plurality of substrates W (for example, 25 substrates) are stacked and stored in one carrier C. The carrier C storing unprocessed substrates W to be carried into the substrate processing apparatus 1 is first placed on the load port 11.

[0029] An indexer robot IR capable of transporting horizontally oriented substrates W one by one is disposed in the indexer block 3. The indexer robot IR can access any of the four load ports 11 and the path 34 provided at the boundary between the indexer block 3 and the coater block 5 shown in Fig. 1, and transfers substrates W between the path 34 and carriers C installed on the load ports 11. The transfer of substrates W by the indexer robot IR is achieved by a hand 36.

[0030] 3. Coater block The coater block 5 is configured to mainly deposit a photoresist layer on the substrate W before exposure processing. The coater block 5 has a second column CL2 located at the rear of the pass 34, a first column CL1 provided to the left of the second column CL2, and a third column CL3 provided to the right of the second column CL2. Therefore, the second column CL2 is located between the first column CL1 and the third column CL3 on the left and right.

[0031] In the first row CL1, chemical processing chambers each having a spin chuck 8 for rotatably supporting the substrate W and a nozzle 10 for discharging a chemical are arranged in the X direction. Therefore, the chemical processing chambers are configured to apply a chemical to the surface of the substrate W. The chemical processing chambers include a BARC chamber 51 for depositing an anti-reflective coating and a resist chamber 53 for depositing a photoresist layer. In the first row CL1 of FIG. 1, two resist chambers 53 or two BARC chambers 51 are arranged in a front-to-back configuration. In the first row CL1, the BARC chambers 51 and the resist chambers 53 are stacked. The BARC chambers 51 and the resist chambers 53 can be switched upside down as needed. The first row CL1 can also have three or more layers of chemical processing chambers.

[0032] The resist chamber 53 can perform not only the deposition of a photoresist layer but also edge exposure related to the removal of the photoresist layer from the peripheral portion of the substrate W. Edge exposure does not necessarily have to be performed in the resist chamber 53, but may be achieved by an edge exposure unit provided separately from the resist chamber 53. The edge exposure unit is provided in the third column CL3 described below or the sixth column CL6 in the developer block 7 described below.

[0033] The second row CL2 is a passageway along which the first central robot CR1, which transports horizontally oriented substrates W, moves back and forth. In addition to the path 34 described above, the first central robot CR1 can access the bark chamber 51 and resist chamber 53 of the first row CL1, the heat treatment chamber 55 and cooling unit 58 (described later) provided in the third row CL3, and the path 54 provided at the boundary between the coater block 5 and the developer block 7 shown in FIG. 1.

[0034] The first center robot CR1 is capable of moving back and forth in the X direction and moving up and down in the Z direction so as to transport the substrate W to each accessible position. The first center robot CR1 can orient the hand 56 that holds the substrate W in any direction, front, back, left or right.

[0035] In the third row CL3, heat treatment chambers 55 for heating substrates W and cooling units 58 for cooling substrates W are arranged in the X direction. The heat treatment chambers 55 are configured with circular hot plates 55a for heating substrates W and circular post-heating treatment plates 55b for performing post-heating treatment to lower the temperature of high-temperature substrates W, arranged in the Y direction. Meanwhile, the cooling units 58 are provided with circular cooling treatment plates 58a for cooling substrates W at room temperature. In the third row CL3, the heat treatment chambers 55 or cooling units 58 are not only arranged in the X direction, but are also stacked in the Z direction to form a stack of chambers. The number of layers in the stack can be changed as appropriate.

[0036] 4. Developer Block The developer block 7 is configured to mainly develop substrates W after exposure processing. The developer block 7 has a fifth column CL5 located at the rear of the path 54, a fourth column CL4 provided to the left of the fifth column CL5, and a sixth column CL6 provided to the right of the fifth column CL5. Therefore, the fifth column CL5 is located between the fourth column CL4 and the sixth column CL6 on the left and right.

[0037] In the fourth row CL4, developing chambers 71 each having a spin chuck 8 for rotatably supporting a substrate W and a nozzle 10 for discharging a chemical solution are arranged in the X direction. In the fourth row CL4 of FIG. 1, two developing chambers 71 are arranged in front of and behind each other. In the fourth row CL4, the developing chambers 71 are stacked. The number of layers in the stack made up of the developing chambers 71 can be changed as appropriate.

[0038] The fifth row CL5 is a passage along which the second center robot CR2, which transports horizontally oriented substrates W, moves back and forth. The second center robot CR2 can access the above-mentioned path 54 as well as the developing chamber 71 in the fourth row CL4, the heat treatment chamber 75, the cooling unit 78, and the path 74, which are provided in the sixth row CL6 and will be described later.

[0039] Like the first center robot CR1, the second center robot CR2 is capable of moving back and forth in the X direction and moving up and down in the Z direction so as to transport the substrate W to each accessible position. The second center robot CR2 can orient the hand 76 that holds the substrate W at least to the front, left, or right.

[0040] In the sixth row CL6, heat treatment chambers 75 for heating substrates W and cooling units 78 for cooling substrates W are arranged in the X direction. The heat treatment chambers 75 have the same configuration as the heat treatment chambers 55 in the third row. Therefore, the heat treatment chambers 75 are configured by arranging circular hot plates 75a and circular post-heating treatment plates 75b in the Y direction. The cooling units 78 have the same configuration as the cooling units 58 in the third row CL3. Therefore, the cooling units 78 are provided with circular cooling treatment plates 78a.

[0041] The path 74 is provided at the rear end of the sixth column CL6. A horizontally oriented substrate W can travel between the developer block 7 and the interface block 9 via the path 74.

[0042] 5. Interface Block The interface block 9 has a path 94 capable of cooling a substrate W placed thereon, a first robot R1 capable of accessing the path 94 and the above-mentioned path 74, and a second robot R2 capable of accessing the path 94 and the stepper 2. The first robot R1 has a hand 961 capable of holding a substrate W placed in a horizontal position on the path 74, and the second robot R2 has a hand 962 capable of holding a substrate W placed in a horizontal position on the path 94.

[0043] The paths 94 are stacked in the Z direction to form a stack.

[0044] 6. Stepper The stepper 2 receives the substrate W before exposure processing, which is transported by the second robot R2, and performs exposure processing to print the circuit pattern of the device onto the photoresist layer of the substrate W. After exposure processing, the substrate W is handed over to the second robot R2.

[0045] 7. Control Unit As shown in Fig. 1, the substrate processing apparatus 1 includes a control unit 131 for controlling the apparatus. Although not shown in Fig. 1, the control unit 131 is also provided with a corresponding storage unit. The control unit 131 is configured, for example, by a CPU (Central Processing Unit). The specific configuration of the control unit is not limited, and for example, each control related to the substrate processing apparatus 1 may be configured by a single processor, or each control may be configured by an individual processor.

[0046] The control related to the control unit 131 includes, for example, control related to the indexer robot IR, the first center robot CR1, the second center robot CR2, the first robot R1, and the second robot R2.

[0047] The storage unit stores control programs and parameters indicating the half-wave time Th (described later). The control unit may be configured as a single device, or may be configured as individual devices corresponding to each control. Furthermore, the substrate processing apparatus 1 of this example is not particularly limited in the configuration of the device that realizes the storage unit.

[0048] 8. Heat treatment chamber In the heat treatment chamber of this example, temperature control is performed using a solid state relay with a zero cross function, which will be described in detail below.

[0049] 2 illustrates the configuration of the heat treatment chamber 55 of this example, particularly the hot plate 55a. The heat treatment chamber 55 includes a housing 12 that prevents the scattering of the solvent volatilized during the heat treatment of the substrate W, and a shutter 14 that can open and close an opening provided in the housing 12.

[0050] A circular hot plate 55a is provided inside the housing 12. The hot plate 55a is configured to heat the substrate W placed thereon to a predetermined temperature. Therefore, the substrate W is placed in a horizontal position on the hot plate 55a. The upper surface of the hot plate 55a serves as a contact surface against which the back surface of the substrate W (the surface opposite to the front surface which is the device surface) comes into contact.

[0051] The hot plate 55a is provided with through holes 16 through which three lift pins 13 capable of holding a substrate W can freely move in and out. The through holes 16 extend in the Z direction and are configured to allow the inserted lift pins 13 to move up and down. When receiving a substrate W from the first central robot CR1, the lift pins 13 are extended. The substrate W is then handed over to the lift pins 13 above the hot plate 55a. When the substrate W is to be heat-treated, the lift pins 13 are contracted. The substrate W then comes into contact with the hot plate 55a and is subjected to heat treatment by the hot plate 55a. When the lift pins 13 are extended, the first central robot CR1 can transfer the substrate W to and from the heat treatment chamber 55. On the other hand, when the lift pins 13 are contracted, the hot plate 55a can perform heat treatment on the substrate W.

[0052] The hot plate 55a includes a heater 15. The heater 15 is an electric heating wire to which an AC voltage of, for example, 60 Hz is applied. The AC voltage is applied to the heater 15 via a power supply wiring 26 connected to an AC power supply 25. The heater 15 corresponds to the load of the present invention.

[0053] 3, the hot plate 55a is provided with a temperature sensor 17 that detects the temperature of the hot plate 55a. The temperature sensor 17 corresponds to the sensor of the present invention.

[0054] The operation rate calculation unit 21 corresponds to the calculation unit of the present invention. The operation rate calculation unit 21 calculates the operation rate of the heater 15 based on the output of the temperature sensor 17. The operation rate is the proportion of time during which power is supplied to the heater 15, which is a load, within a control period. For example, when the temperature of the hot plate 55a is room temperature, the operation rate calculation unit 21 sets the operation rate of the heater 15 to 100% so that the hot plate 55a can quickly perform heat treatment on the substrate W. When the temperature of the hot plate 55a is at a temperature (e.g., 100°C) set as the heat treatment temperature, the operation rate calculation unit 21 sets the operation rate of the heater 15 to 0% so that the hot plate 55a is not heated any further. In addition, when the temperature of the hot plate 55a drops from 100°C to 99.9°C, the operation rate calculation unit 21 sets the operation rate of the heater 15 to, for example, 5% to quickly return the temperature of the hot plate 55a to the set temperature of 100°C while suppressing temperature overshoot. In other words, the operation rate calculation unit 21 realizes a feedback function of the temperature of the heat treatment chamber 55.

[0055] A control period that determines the timing for reviewing the operation rate is set in the operation rate calculation unit 21. The operation rate calculation unit 21 calculates the operation rate of the heater 15 for each control period based on the output of the temperature sensor 17. The control period is, for example, 100 msec.

[0056] The ON signal generating unit 22 outputs an ON signal for each control cycle based on the operation rate calculated by the operation rate calculating unit 21. The ON signal is a digital signal that instructs the heater 15 to operate. First, this ON signal will be described. If the operation rate calculated by the operation rate calculating unit 21 is, for example, 50%, the ON signal generating unit 22 generates an ON signal having a temporal length that is half the control cycle and outputs it to the heater 15. In this way, the ON signal generating unit 22 is configured to generate an ON signal having a temporal length proportional to the operation rate for each control cycle, and operate the heater 15 according to the operation rate. In this way, the ON signal generating unit 22 performs feedback control by adjusting the temporal length of the ON signal according to the operation rate and inputting it to the relay control unit 23.

[0057] The relay control unit 23 corresponds to the control unit of the present invention. The relay control unit 23 is configured to be interposed between the output of the on signal generation unit 22 and the input of the solid state relay 24, which will be described later. The relay control unit 23 receives an on signal from the on signal generation unit 22 and generates an extended on signal as necessary. The on signal or extended on signal is output to the solid state relay 24. The operation of the relay control unit 23 is closely related to the zero cross function of the solid state relay 24, which will be described later, and will be described in detail later.

[0058] Based on the ON signal or the extended ON signal, the solid-state relay 24 controls whether or not to apply an AC voltage to the heater 15. Basically, the solid-state relay 24 is configured to apply an AC voltage to the heater 15 only while the ON signal or the extended ON signal is being input.

[0059] The AC power supply 25 supplies AC power to the solid-state relay 24. The solid-state relay 24 passes or does not pass the power supplied from the AC power supply 25 to the heater 15 based on an ON signal or an extended ON signal.

[0060] The solid-state relay 24 in this example has a zero-cross function, which will be described below. The zero-cross function is a function that causes the heater 15 to output a voltage from 0 V according to the waveform of the AC voltage. Therefore, it takes some time from when an ON signal is input to the solid-state relay 24 until the application of AC voltage to the heater 15 begins. This is because the solid-state relay 24 waits until the AC voltage reaches 0 V before starting to apply voltage.

[0061] 4 illustrates the zero-cross function. The output of AC power supply 25 is a sine wave whose voltage changes at a cycle of, for example, 60 Hz. Solid-state relay 24 monitors the AC voltage supplied from AC power supply 25 and waits until an ON signal or an extended ON signal arrives from relay control unit 23.

[0062] As shown in the waveform diagram of Figure 4, when an ON signal 41 is input to the solid-state relay 24, the solid-state relay 24 refrains from applying AC voltage to the heater 15 while the ON signal 41 is being input until the AC voltage becomes 0 V. Then, once the AC voltage becomes 0 V, the solid-state relay 24 starts applying AC voltage to the heater 15. In this way, the function of starting the application of AC voltage from 0 V is the zero-cross function. In this way, the solid-state relay 24 provided on the power supply wiring 26 has a zero-cross function that starts applying AC voltage to the heater 15 when the power supply voltage becomes 0 V upon input of an ON signal from the ON signal generating unit 22.

[0063] Thereafter, the solid-state relay 24 monitors whether or not the ON signal 41 is being input each time the AC voltage becomes 0 V. If the input of the ON signal 41 has stopped when the AC voltage becomes 0 V, the solid-state relay 24 stops applying the AC voltage to the heater 15 from that point on.

[0064] The zero-cross function prevents a sudden high voltage from being applied to the heater 15 when the ON signal 41 is input, thereby preventing an inrush current from occurring in the heater 15. The zero-cross function can also suppress radiation noise caused by the inrush current. Suppressing radiation noise prevents malfunctions in the control units of the substrate processing apparatus 1.

[0065] 9. Relay control section operation Next, we will explain the operation of the relay control unit 23. The relay control unit 23 is located between the on signal generation unit 22 and the solid-state relay 24 in the functional block diagram of Fig. 3, and is configured to pass the on signal or output an extended on signal when an on signal is input.

[0066] 5 illustrates how the relay control unit 23 passes the ON signal generated by the ON signal generation unit 22 to the solid-state relay 24. The ON signal generation unit 22 generates an ON signal 41 having a length over time that corresponds to the availability output from the availability calculation unit 21 for each control period D. The generated ON signal 41 is output to the relay control unit 23. Therefore, the ON signal 41 is generated for each control period D, and the ON signal 41 is input to the relay control unit 23 for each control period D. In this way, the relay control unit 23 passes the ON signal 41 to the solid-state relay 24 when an ON signal 41 that is equal to or longer over time than the above-mentioned half-wave time Th is input.

[0067] The relay control unit 23 passes the ON signal 41 to the solid-state relay 24 when the length over time of the ON signal 41 input from the ON signal generation unit 22 is equal to or longer than a half-wave time Th, which is half the period of the AC power supplied to the solid-state relay 24. The solid-state relay 24 applies an AC voltage to the heater 15 based on this ON signal 41. In the case of FIG. 5, the length over time of the ON signal 41 is less than twice the half-wave time Th, so the heater 15 is driven by a half-wave voltage that is half the period of the AC power. The voltage change at this time resembles either a mountain-shaped waveform ranging from sin(0) to sin(π) of the sinusoidal AC voltage, or a valley-shaped waveform ranging from sin(π) to sin(2π).

[0068] 6 illustrates the operation of the relay control unit 23 when the length over time of the ON signal 41 input from the ON signal generation unit 22 is shorter than the half-wave time Th. In this case, the ON signal 41 is too short over time to properly control the heater 15. The relay control unit 23 does not allow such an ON signal 41 to pass through the solid-state relay 24. In this example, even though the ON signal 41 is generated by the ON signal generation unit 22, a control period D is generated in which the heater 15 does not operate. In this way, when an ON signal 41 shorter over time than the half-wave time Th is input, the relay control unit 23 does not allow the ON signal 41 to pass through the solid-state relay 24.

[0069] In the next control cycle D, the relay control unit 23 combines the input ON signal 41 with the ON signal 41 that was not passed to the solid-state relay 24 over time to generate an extended ON signal 42 in which the ON signal 41 is extended. If the extended ON signal is equal to or longer than the half-wave time Th, the relay control unit 23 outputs the extended ON signal 42 to the solid-state relay 24. This extended ON signal has a temporal length that is long enough to appropriately control the heater 15. In this way, the relay control unit 23 operates to extend the next input ON signal by the temporal length of the ON signal that was not passed. In this way, the relay control unit 23 generates an extended ON signal whose temporal length is longer than the half-wave time Th and outputs it to the solid-state relay 24.

[0070] If the length over time of the generated extended ON signal 42 is still shorter than the half-wave time Th, the relay control unit 23 refrains from outputting such an extended ON signal 42 to the solid-state relay 24. In the next control cycle D, the relay control unit 23 further combines over time the output ON signal 41 and the extended ON signal 42 that was not output to the solid-state relay 24, thereby re-extending the extended ON signal 42. The relay control unit 23 continues this extension operation of combining ON signals until the extended ON signal becomes longer over time than the half-wave time Th, and outputs an extended ON signal 42 whose length over time is equal to or longer than the half-wave time Th to the solid-state relay 24.

[0071] The length over time of the extended ON signal 42 is the sum of the lengths over time of the merged ON signals 41. This relationship remains the same even if three or more ON signals 41 are merged to generate the extended ON signal 42.

[0072] 10. Control operation flowchart 7 is a flowchart illustrating the operation of relay control section 23. Relay control section 23 will be described below with reference to this drawing.

[0073] Step S11: The on signal 41 is input to the relay control unit 23.

[0074] Step S12: The relay control unit 23 determines whether the ON signal 41 is equal to or longer than the half-wave time Th. If the determination is false (N), the process proceeds to step S13, and if true (Y), the process proceeds to step S15. Step S12 corresponds to the comparison step of the present invention. Step S12 is configured to compare the length of the ON signal over time with the half-wave time Th.

[0075] Step S13: The relay control unit 23 combines the multiple ON signals 41 over time to generate an extended ON signal 42. Step S13 corresponds to the extended ON signal generating step of the present invention. Step S13 is configured to combine the multiple ON signals 41 over time to generate an extended ON signal whose length over time is equal to or greater than the half-wave time Th when the length over time of the ON signals is less than the half-wave time Th.

[0076] Step S14: The relay control unit 23 determines whether the extended ON signal 42 is equal to or longer than the half-wave time Th. If the determination is false (N), the process returns to step S13, and if true (Y), the process proceeds to step S15. In other words, the relay control unit 23 of this example can generate an extended ON signal by cumulatively extending the input ON signal by the length over time of the multiple ON signals that were not allowed to pass.

[0077] Step S15: The relay control unit 23 outputs the ON signal 41 or the extended ON signal 42 to the solid-state relay 24. This completes the signal processing by the relay control unit 23 for the single ON signal 41 or the extended ON signal 42. Step S15 corresponds to the voltage control step of the present invention. Step S15 controls the AC voltage applied to the heater 15 based on the ON signal or the extended ON signal. This control is specifically realized by the solid-state relay 24 having a zero-cross function.

[0078] 11. Substrate processing flow Next, the flow of substrate processing in this example will be described with reference to the flowchart of Fig. 8. In the flowchart of Fig. 8, the temperature of the hot plate 55a in the heat treatment chamber 55 is kept constant by the operation of the relay control unit 23 described above. The same applies to the heat treatment chamber 75.

[0079] Step T11: The unprocessed substrate W stored in the carrier C is transported to the path 34 by the indexer robot IR.

[0080] Step T12: The first central robot CR1 in the coater block 5 transports the substrate W obtained from the path 34 to the cooling unit 58. The substrate W is subjected to a cooling process in the cooling unit 58.

[0081] Step T13: The first central robot CR1 transports the substrate W in the cooling section 58 to the BARC chamber 51. The substrate W is subjected to the BARC chamber 51 to undergo the film formation process of an anti-reflection film.

[0082] Step T14: The first central robot CR1 transports the substrate W from the bark chamber 51 to the heat treatment chamber 55. The substrate W is subjected to heat treatment in the heat treatment chamber 55.

[0083] Step T15: The first central robot CR1 transports the substrate W from the heat treatment chamber 55 to the resist chamber 53. In the resist chamber 53, the substrate W is subjected to a film formation process of a photoresist layer.

[0084] Step T16: The first central robot CR1 transports the substrate W from the resist chamber 53 to the heat treatment chamber 55. The substrate W is subjected to heat treatment in the heat treatment chamber 55.

[0085] Step T17: The first central robot CR1 transports the substrate W from the heat treatment chamber 55 to the path 54. The substrate W on which the photoresist layer has been formed in this manner leaves the coater block 5.

[0086] Step T18: The second central robot CR2 in the developer block 7 transports the substrate W from the path 54 to the path 74.

[0087] Step T19: The first robot R1 in the interface block 9 transports the substrate W on the path 74 to the path 94.

[0088] Step T31: The second robot R2 transports the substrate W on the path 94 to the stepper 2. The stepper 2 performs exposure processing on the substrate W through a mask corresponding to the circuit pattern of the required device.

[0089] Step T32: The second robot R2 retrieves the substrate W that has been subjected to the exposure processing from the stepper 2 and transports it to the path 94.

[0090] Step T33: The first robot R1 transports the substrate W from the path 94 to the path 74. In this way, the substrate W exits the interface block 9 after the exposure processing.

[0091] Step T34: The second central robot CR2 in the developer block 7 transports the substrate W on the path 74 to the cooling unit 78. The substrate W is subjected to a cooling process in the cooling unit 78.

[0092] Step T35: The second central robot CR2 transports the substrate W in the cooling section 78 to the developing chamber 71. The substrate W is subjected to the developing process in the developing chamber 71.

[0093] Step T36: The second central robot CR2 transports the substrate W from the developing chamber 71 to the heat treatment chamber 75. The substrate W is subjected to heat treatment in the heat treatment chamber 75.

[0094] Step T37: The second central robot CR2 transports the substrate W from the heat treatment chamber 75 to the path 54. In this way, the substrate W that has been subjected to the development process leaves the developer block 7.

[0095] Step T38: The first central robot CR1 in the coater block 5 transports the substrate W in the path 54 to the path 34. In this way, the developed substrate W exits the coater block 5. The substrate W in the path 34 is returned to the original carrier C by the indexer robot IR.

[0096] 12. Effects of the present invention The above-described configuration includes an ON signal generator 22 that outputs an ON signal every control cycle, and a relay controller 23 that, when an ON signal shorter than the half-wave time Th is input, does not pass the ON signal to the solid-state relay 24 and extends the next ON signal input by the length of the ON signal that was not passed. This generates an extended ON signal whose length is equal to or longer than the half-wave time Th and transmits it to the solid-state relay 24. ON signals shorter than the half-wave time Th generated by the ON signal generator 22 are combined and extended, and this is reflected in the control of the solid-state relay 24, which has a zero-cross function. This is because the length of the extended ON signal is equal to or longer than the half-wave time Th, and a point in time when the AC voltage becomes 0 V always occurs during the output of the extended ON signal. This configuration prevents the generation of ignored ON signals, enabling more precise operation control of the heater 15.

[0097] That is, the control of the heater 15 by the solid-state relay 24 with the zero-cross function may operate by overlooking an ON signal having a short duration over time. Specifically, as shown in Fig. 9, if an ON signal 41 falls between a first point P1 at which the AC voltage becomes 0 V and a second point P2 at which the AC voltage next becomes 0 V, there is no time when the AC voltage becomes 0 V while the ON signal 41 is being generated, and therefore the voltage applied to the heater 15 does not change from 0 V regardless of the presence of the ON signal 41.

[0098] In this regard, according to this embodiment, an ON signal having such a short temporal length that it cannot control the heater 15 is not input to the solid-state relay 24. This is because ON signals having a temporal length less than the half-wave time Th are combined into an extended ON signal and then output to the solid-state relay 24.

[0099] According to the above-described configuration, there is provided the temperature sensor 17 and the operation rate calculation unit 21 that calculates the operation rate of the heater 15 based on the output of the temperature sensor 17, and the ON signal generation unit 22 performs feedback control by adjusting the length of the ON signal over time according to the operation rate and inputting it to the relay control unit 23. With this configuration, it becomes easy to generate the ON signal required to control the heater 15.

[0100] According to the above-described configuration, the relay control unit 23 generates an extended ON signal by cumulatively extending the input ON signal by the time lengths of the multiple ON signals that were not passed. By merging three or more ON signals to generate an extended ON signal in this manner, even if there is an ON signal that is significantly shorter in time than the half-wave time Th, it can be reflected in the control of the heater 15 without being overlooked.

[0101] 13. Modified embodiments of the present invention The present invention is not limited to the configurations of the above-described embodiments, but can be modified as follows.

[0102] <Variation 1> By further improving the above-described configuration, it is possible to further strictly control the heater 15. That is, according to the relay control unit 23 of this modification, the length of the extended ON signal over time and the output timing can be optimized based on the operating rate, thereby making it possible to set an extremely short control period.

[0103] The availability calculation unit 21, the ON signal generation unit 22, and the relay control unit 23 calculate the availability, generate the ON signal, and control the solid-state relay 24 based on the set control period. The shorter the control period, the stricter the control of the heater 15. This is because the shorter the control period, the more frequently temperature adjustment is performed.

[0104] However, since the ON signal generating unit 22 has a predetermined operating clock, the length of the ON signal over time is discrete, and the ON signal can only have a length over time that is a multiple of a certain unit time S.

[0105] The unit time S is, for example, about 3 msec, which is sufficiently short for general feedback control, and the length of the ON signal over time can be considered continuous. However, as the control period approaches 3 msec, the discrete nature of the length of the ON signal over time cannot be ignored.

[0106] For example, if the control period is set to a short value of about 30 msec, the ON signal can have only ten different temporal lengths: 3 msec, 6 msec, 9 msec, 12 msec, 15 msec, 18 msec, 21 msec, 24 msec, 27 msec, and 30 msec. If the half-wave time Th is, for example, 8.3 msec, ON signals with temporal lengths of 3 msec or 6 msec are too short to properly control the solid-state relay 24. Therefore, ON signals or extended ON signals with eight different temporal lengths ranging from 9 msec to 30 msec are input to the solid-state relay 24.

[0107] To achieve such precise temperature control of heater 15, the problem arises when controlling heater 15 at extremely low output, and the timing of outputting the 9 msec extended ON signal, which has the shortest time duration, is important. The relay control unit 23 of this modified example solves this problem by determining the output timing of the extended ON signal based on the operating rate.

[0108] That is, in this modified example, not only the ON signal from the ON signal generator 22 but also the operation rate from the operation rate calculator 21 is sent to the relay controller 23. The relay controller 23 accumulates the operation rate while extending the ON signal and determines the output timing of the extended ON signal based on the accumulated operation rate. The relay controller 23 in this modified example accumulates the operation rate calculated by the operation rate calculator 21 for each control period D.

[0109] 10 shows a state in which the relay control unit 23 has extended the ON signal three times in succession. The relay control unit 23 refrained from outputting the extended ON signal to the solid-state relay 24 in the first cycle C1, the second cycle C2, and the third cycle C3 of the control period D.

[0110] In this modification, the output timing of the extended ON signal is determined based on a converted time obtained by converting the availability into time. The converted time can be calculated for each control cycle, and is specifically the product of the length of the control cycle and the availability. For example, if the control cycle is 30 msec and the availability is 50%, the converted time is 15 msec, which is half of 30 msec.

[0111] In FIG. 11, the availability on the vertical axis in FIG. 10 is replaced with converted time. Like the availability, the converted time can be accumulated for each control period D. In this way, the relay control unit 23 can obtain the converted time by converting the accumulated availability into the length of the on signal over time. Unlike the actual on signal, the converted time can take on a continuous value.

[0112] If the converted time related to the accumulated operation rate is shorter than the half-wave time Th, it is too early to output an extended ON signal. This is because the converted time basically indicates the length of the extended ON signal over time. Even if an extended ON signal is output in the first cycle C1, the second cycle C2, and the third cycle C3 of the control period D, the length over time is too short to properly control the heater 15. Therefore, the relay control unit 23 refrains from outputting an extended ON signal to the solid-state relay 24 in the first cycle C1, the second cycle C2, and the third cycle C3.

[0113] When the converted time exceeds the half-wave time Th in the fourth cycle C4 of the control period D, the extended ON signal generated at that time also exceeds the half-wave time Th. Therefore, the relay control unit 23 determines to output the extended ON signal to the solid-state relay 24 in the fourth cycle C4. In this way, the relay control unit 23 sets a reference point in time at which the converted time exceeds the half-wave time Th. The extended ON signal is generated at the set reference point in time and sent to the solid-state relay 24. The following describes how the length of the extended ON signal over time is determined based on the converted time.

[0114] FIG. 12 shows how the overrun time AT is added to the converted time in accordance with the extended ON signal, which takes discrete values. The ON signal generated by the ON signal generator is a discrete length, which is an integer multiple of a predetermined unit time S. For example, if the maximum output is 100 percent when power is continuously supplied to the load throughout the control period, the ON signal's length will be a discrete time length, such as 10 percent or 20 percent of the maximum output. Therefore, the extended ON signal generated by merging the ON signals is also discrete, being an integer multiple of the unit time S. The unit time S is a unique value determined by the operating clock of the ON signal generator 22. If the converted time, which increases from S, 2S, and 3S, is compared with the half-wave time Th to determine the output timing of the extended ON signal based on the unit time S, the output timing of the extended ON signal will be shifted behind the ideal timing. This is because, for example, when the converted time increases from 3S to 4S, the half-wave time Th is suddenly removed. The ideal timing is just before the conversion time reaches 4S.

[0115] In this regard, the converted time calculated from the accumulated availability is not bound by the unit time S but is continuous, which is convenient for determining the output timing of the extended ON signal. In other words, if the reference time point is determined by the method described in Fig. 11, the extended ON signal will be sent to the solid-state relay 24 before the converted time exceeds 4S.

[0116] However, the length of the extended ON signal over time is limited to a multiple of the unit time S. On the other hand, the converted time is continuous. Therefore, the length of the extended ON signal over time is not the converted time itself. In this regard, when the relay control unit 23 determines to output an extended ON signal, it adds the excess operation time AT to the converted time to make the cumulative value of the converted time a multiple of the unit time S. However, since it is preferable that the length of the extended ON signal over time be as close to the converted time as possible, the excess operation time AT is set to a value smaller than the unit time S. In this case, the length of the extended ON signal over time is the shortest length that is equal to or greater than the half-wave time Th.

[0117] In practice, the relay control unit 23 generates an extended ON signal by additionally extending at least the unit time S at the reference time point. In the above description, the excess operating time AT is added to the converted time to generate an extended ON signal having a temporal length three times the unit time S. If this operation is viewed in accordance with the embodiment as an ON signal extension operation, the operation can be explained as follows. That is, the relay control unit 23 further extends the ON signal having a temporal length equivalent to twice the unit time S stored in the third cycle C3 by an additional unit time S at the reference time point and sends it to the solid-state relay 24. That is, the relay control unit 23 generates an extended ON signal by additionally extending the ON signal by at least the unit time S at the reference time point.

[0118] 13 shows how an extended ON signal 42 having a length three times the unit time S is sent from the relay control unit 23 to the solid-state relay 24 in the fourth cycle C4 of the control period D. The ideal length of the extended ON signal 42 in the fourth cycle C4 is slightly shorter than three times the unit time S. However, because the length of the extended ON signal 42 can only increase per unit time S, the actual length of the extended ON signal 42 is three times the unit time S. The actual length of the extended ON signal 42 is longer than the ideal length by the excess operating time AT.

[0119] Therefore, in the fourth cycle C4, the heater 15 operates slightly more than ideally. This modified example has a function to suppress the influence of this excessive operation of the heater 15.

[0120] That is, when the relay control unit 23 finishes the fourth cycle C4 of the control period D and enters the fifth cycle C5, it subtracts the excess operation time AT and accumulates the converted time. In the explanation of FIG. 11, since four control periods D were required for the relay control unit 23 to output the extended ON signal, it is expected that four control periods D will be required for the relay control unit 23 to output the next extended ON signal. In this situation, if no measures are taken to determine the output timing of the next extended ON signal, the influence of the excess operation time AT will make it impossible to control the heater 15 precisely. This is because the excess operation time AT occurs one after another every four control periods D, and as the heater 15 is controlled, the actual control will differ significantly from the ideal.

[0121] Therefore, the relay control unit 23 operates as shown in FIG. 14. That is, in order to cancel out the excess operation time AT, the relay control unit 23 subtracts the excess operation time AT from the converted time when accumulating the converted time that determines the output timing of the extended ON signal. That is, in the fifth cycle C5 of the control period D, the operation rate appears to be smaller by the subtracted excess operation time AT. From the sixth cycle C6 onwards, the converted time is accumulated as in the first cycle C1 to the fourth cycle C4. This operation continues until the converted time exceeds the half-wave time Th. Therefore, in the example of FIG. 11, the operation of subtracting the excess operation time AT from the converted time is expected to occur every four control periods D.

[0122] In this way, the relay control unit 23 of this modified example operates by subtracting the excess operating time AT, which is obtained by subtracting the converted time at the reference point from three times the unit time S, which is the length over time of the extended on signal transmitted to the solid-state relay 24 at the reference point, from the converted time when determining the next reference point.

[0123] According to the configuration of this modified example, the relay control unit 23 accumulates the operation rates of the heater 15 calculated by the operation rate calculation unit 21 for each operation cycle in the ON signal generation unit 22, converts the accumulated operation rate into the length of the ON signal over time to obtain the converted time, sets a reference point at which the converted time exceeds the half-wave time Th, and generates an extended ON signal by additionally extending at least a predetermined unit time at the reference point. With this configuration, it is possible to improve the responsiveness of control even if the length of the ON signal over time generated by the ON signal generation unit 22 is discrete and is a predetermined integer multiple.

[0124] <Variation 2> Although the relay control unit 23 of the present invention relates to the temperature control of the hot plate 55a, the present invention is not limited to this configuration and can also be used, for example, to control the light intensity of a light source lamp used for lamp heating. In addition, the relay control unit 23 of the present invention can also be applied to the rotation control of a motor provided in the substrate processing apparatus 1. [Explanation of symbols]

[0125] 1. Substrate processing equipment 1A housing 2 Stepper 3 Indexer Blocks 5 Coater Block 7 Developer Block 8 Spin Chuck 9 Interface Blocks 10 nozzles 11 Loading Port 12. Case 13 Lift pin 14 Shutter 15 Heater 16 through holes 17 Temperature Sensor 21 Operating rate calculation section 22 ON signal generator 23 Relay control section 24 Solid State Relay 25 AC power supply 26 Power wiring 34 Pass 36 hands 41 ON signal 42 Extended On Signal 51 Bark Chamber 53 Resist Chamber 54 Pass 55 Heat Treatment Chamber 55a Hot plate 55b Post-heat treatment plate 56 hands 58 Cooling section 58a Cooling treatment plate 71 Development chamber 74 passes 75 Heat Treatment Chamber 75a hot plate 75b Post-heat treatment plate 76 hands 78 Cooling section 78a Cooling treatment plate 94 Pass 131 Control Unit 961 hands 962 hands AT Excessive Operating Time C Carrier C1 1st cycle C2 2nd Cycle C3 3rd Cycle C4 4th Cycle C5 5th Cycle C6 6th Cycle CL1 1st row CL2 2nd row CL3 3rd row CL4 4th row CL5 5th row CL6 6th row CR1 1st Center Robot CR2 Second Center Robot D control period IR Indexer Robot P1 First time point P2 Second time point R1 First Robot R2 Second Robot S unit time Th half wave time W substrate

Claims

1. In a substrate processing apparatus for processing a substrate, a load section to which an AC voltage is applied; a solid-state relay having a zero-cross function that starts applying an AC voltage to the load section when the AC voltage becomes 0 V upon input of an ON signal; an ON signal generating unit that outputs the ON signal for each control period; a control unit that is interposed between the output of the on signal generating unit and the input of the solid-state relay, and that, when an on signal that is equal to or longer in time than a half-wave time, which is half the cycle of an AC voltage, is input, passes the on signal to the solid-state relay, and, when an on signal that is shorter in time than the half-wave time is input, does not pass the on signal to the solid-state relay, and extends the next input on signal by the length in time of the on signal that was not passed, and generates an extended on signal whose length in time is longer than the half-wave time and transmits it to the solid-state relay. A substrate processing apparatus characterized by:

2. 2. The substrate processing apparatus according to claim 1, A sensor, a calculation unit that calculates an availability rate, which is a time rate at which power is supplied to the load unit within the control period, based on an output of the sensor, The ON signal generating unit performs feedback control to input the ON signal to the control unit at a time-dependent length corresponding to the operation rate. A substrate processing apparatus characterized by:

3. 3. The substrate processing apparatus according to claim 2, the length of the ON signal generated by the ON signal generating unit is discrete and is an integer multiple of a predetermined unit time; The control unit accumulating the operation rates calculated by the calculation unit for each control period; The accumulated operating rate is converted into the time length of the ON signal to obtain a continuous converted time; setting a reference time point at which the converted time is equal to or exceeds the half-wave time; generating the extension-on signal by additionally extending at least the unit time at the reference time point; an excess operating time obtained by subtracting the converted time at the reference time from the time length of the extended ON signal transmitted to the solid-state relay at the reference time is subtracted from the converted time when determining the next reference time; A substrate processing apparatus characterized by:

4. 4. The substrate processing apparatus according to claim 3, The control unit generates the extension-on signal by additionally extending at least the unit time before the reference time point is reached, and transmits the extension-on signal to the solid-state relay. A substrate processing apparatus characterized by:

5. 3. The substrate processing apparatus according to claim 2, The sensor is a temperature sensor that detects a temperature. A substrate processing apparatus characterized by:

6. 2. The substrate processing apparatus according to claim 1, The control unit cumulatively extends the input ON signal by the time lengths of the multiple ON signals that were not passed, to generate the extended ON signal. A substrate processing apparatus characterized by:

7. A substrate processing method for a substrate processing apparatus including: a load unit to which an AC voltage is applied; a solid-state relay having a zero-cross function that starts applying an AC voltage to the load unit when the AC voltage becomes 0 V upon input of an ON signal; and an ON signal generation unit that periodically outputs the ON signal, a comparison step of comparing the time length of the ON signal with a half-wave time, which is half the period of an AC voltage; an extended ON signal generating step of merging a plurality of ON signals to generate an extended ON signal having a temporal length equal to or longer than the half wave time when the temporal length of the ON signal is less than the half wave time; a voltage control step of controlling an AC voltage applied to the load section based on the on signal or the extended on signal. A substrate processing method comprising:

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