Substrate processing apparatus, method of manufacturing semiconductor device, substrate processing method, and recording medium

Abstract

It is possible to suppress excessive temperature rise of a pipe heater. A pipe heater that heats a gas pipe that supplies a gas to a processing chamber that processes a substrate, a temperature detecting section that detects a temperature of the gas pipe, a temperature regulator that outputs an operation amount indicating a power to be supplied to the pipe heater based on the temperature detected by the temperature detecting section, and performs control to make the temperature of the gas pipe approach a target value, and a higher-level controller that controls start and stop of heating of the gas pipe under control of the temperature regulator are provided. After the heating of the gas pipe under control of the temperature regulator is started, in a case where a time at which the operation amount becomes a maximum value is equal to or more than a threshold value, the higher-level controller controls the temperature regulator to stop the heating of the gas pipe.

Description

Technical Field

[0001] This disclosure relates to a substrate processing apparatus, a method for manufacturing a semiconductor device, a substrate processing method, and a procedure. Background Technology

[0002] As a step in the manufacturing process of a semiconductor device, sometimes the following process is performed: the power supply to the heater is controlled based on the temperature measured by a temperature sensor installed inside the furnace, thereby controlling the temperature inside the furnace while forming a film on a substrate. In addition, sometimes a technique is used that can stably continue to control the temperature inside the furnace even if the temperature sensor fails (see, for example, Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2007-88394 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] Alternatively, the following process is sometimes performed: a strip or ribbon-like pipe heater is wound around the gas pipe to heat it while forming a film on a substrate. In this case, a temperature sensor such as a thermocouple (TC) is used to monitor the temperature of the gas pipe.

[0008] Furthermore, in structures where the thermocouple and the piping heater are separate, for example, the thermocouple is installed on a gas pipe and the piping heater is wound around it for temperature monitoring. In such cases, if the temperature monitoring malfunctions due to the thermocouple falling off, power may be continuously supplied to the piping heater, causing it to overheat.

[0009] The purpose of this disclosure is to provide a technique for suppressing excessive temperature rise in piping heaters.

[0010] Methods for solving problems

[0011] According to one aspect of this disclosure, the following technology is provided, possessing:

[0012] A piping heater that heats gas piping that supplies gas to the processing chamber of the processing substrate;

[0013] A temperature detection unit that detects the temperature of the gas piping;

[0014] A temperature regulator, based on the temperature detected by the temperature detection unit, outputs an operating amount indicating the amount of power to be supplied to the piping heater, thereby controlling the temperature of the gas piping to approach a target value; and

[0015] The host controller controls the start and stop of heating of the gas piping under the control of the temperature regulator.

[0016] After the heating of the gas piping under the control of the temperature regulator begins, if the time for which the operation quantity reaches its maximum value exceeds a threshold, the host controller controls the temperature regulator to stop the heating of the gas piping.

[0017] Invention Effects

[0018] According to this disclosure, it is possible to suppress excessive heating of the piping heater. Attached Figure Description

[0019] Figure 1 This is a schematic longitudinal sectional view of a longitudinal processing furnace of a substrate processing apparatus according to one embodiment of the present disclosure.

[0020] Figure 2 This is a diagram illustrating the functional structure of the controller of the substrate processing apparatus in one embodiment of the present disclosure.

[0021] Figure 3 This is a flowchart illustrating a substrate processing step in one embodiment of the present disclosure.

[0022] Figure 4 (A) is Figure 1 An enlarged view of part A shown in the image. Figure 4 (B) is Figure 4 Sectional view of (A) along line A-1. Figure 4 (C) represents Figure 4 A modified example of the cross-sectional view of line A-1 of (A). Figure 4 (D) is a partially enlarged view illustrating the structure of a piping heater in one embodiment of the present disclosure.

[0023] Figure 5 This is a diagram illustrating the structure of a temperature regulator in one embodiment of the present disclosure.

[0024] Figure 6 This is a flowchart illustrating the operation of a programmable logic controller (PLC) in one embodiment of the present disclosure.

[0025] Figure 7 (A) is a graph showing the time variation of the output value of the belt heater, the temperature of the belt heater, and the measurement temperature of the thermocouple in this embodiment. Figure 7 (B) is a graph showing the time-varying values ​​of the belt heater, the temperature of the belt heater, and the temperature measured by the thermocouple in the comparative example. Detailed Implementation

[0026] (1) Structure of the substrate processing device

[0027] The embodiments will now be described using the accompanying drawings. However, in the following description, the same reference numerals will sometimes be used to refer to the same constituent elements and repeated descriptions will be omitted. Furthermore, in order to make the description clearer, the drawings may sometimes schematically show the width, thickness, shape, etc. of each part compared to the actual embodiment, but these are merely examples and do not limit the interpretation of this disclosure.

[0028] (Processing furnace)

[0029] like Figure 1 As shown, a reaction tube 203 is provided inside the heater 207, which serves as the first heating unit, as a processing container for processing the substrate, i.e., the wafer 200. An inlet flange 210, serving as the furnace opening, is provided at the lower end of the reaction tube 203. The inlet flange 210 is hermetically sealed by a sealing cap 219, which serves as the cover, via an O-ring 220, which is an airtight component. An inner tube 204 is mounted on the inlet flange 210. At least the reaction tube 203, the inner tube 204, the inlet flange 210, and the sealing cap 219 form the processing chamber 201. A crystal boat 217, serving as a substrate holding part, is provided on the sealing cap 219 via a quartz cover 218. The quartz cover 218 and the crystal boat 217 are moved in and out of the processing chamber 201. Multiple wafers 200 for batch processing are horizontally and multi-layered in the crystal boat 217. Heater 207 heats the wafer 200 inserted into processing chamber 201 to a predetermined temperature.

[0030] Gas piping 10, which serves as the gas pipe supplying the first processing gas (raw material gas), and gas piping 11, which supplies the second processing gas (reaction gas), are connected within the processing chamber 201. On gas piping 10, starting from the upstream side, are a gas supplier 4 for supplying the raw material gas (serving as the first processing gas), a flow controller (mass flow controller, MFC) 41 for controlling the flow rate of the raw material gas from the gas supplier 4, and a valve 34 for opening and closing the flow path of the raw material gas. The raw material gas is supplied from gas piping 10 through gas supplier 4, MFC 41, valve 34, and nozzle 234 into the processing chamber 201. Gas piping 10, MFC 41, valve 34, and nozzle 234 constitute the first processing gas supply system (also called the raw material gas supply system).

[0031] On the gas piping 11, starting from the upstream side, there is a gas supplier 5 for supplying the reaction gas, which serves as the second processing gas; an MFC 32 for controlling the flow rate of the reaction gas from the gas supplier 5; and a valve 35 for opening and closing the flow path of the reaction gas. The reaction gas is supplied from the gas piping 11 through the gas supplier 5, the MFC 32, the valve 35, and through a nozzle 233 installed in the processing chamber 201 to the processing chamber 201. The gas piping 11, the MFC 32, the valve 35, and the nozzle 233 constitute the second processing gas supply system (also called the reaction gas supply system).

[0032] A gas pipe heater 22 is provided around the gas pipe 10 from the gas supplier 4 to the processing chamber 201 to heat the gas pipe 10. The gas pipe heater 22 (hereinafter also referred to as the first pipe heater) uses a strip heater, i.e., a band heater, as the second heating part in the embodiment.

[0033] In gas piping 10, gas piping 40 for supplying inert gas is connected downstream of valve 34 via valve 39. A gas piping heater 22 is also provided between the connection point of gas piping 40 and valve 39 and gas piping 10. In addition, in gas piping 11, gas piping 6 for supplying inert gas is connected downstream of valve 35 via MFC 33, valve 36, and valve 35.

[0034] In addition, in this embodiment, a gas piping heater is not provided in the second processing gas supply system, but the gas piping heater 22 in this embodiment may be appropriately provided according to the second processing gas.

[0035] The processing chamber 201 is connected to the vacuum pump 246 via an exhaust pipe 231 on the exhaust side, which exhausts the gas. The exhaust pipe 231, APC valve 243, and vacuum pump 246 constitute the gas exhaust system. Around the exhaust pipe 231 from the reaction tube 203 to the vacuum pump 246, an exhaust pipe heater 20 (hereinafter also referred to as the second pipe heater) is provided as a third heating unit to heat the exhaust pipe 231. Furthermore, the exhaust pipe heater 20 typically uses a jacketed heater with molded insulating material, and the aforementioned strip heater is used for thinner pipes with a nominal diameter of 1 / 2 inch or less. Hereinafter, the exhaust pipe heater 20 and the gas pipe heater 22 are sometimes collectively referred to as pipe heater 310. Similarly, gas pipes 6, 10, 11, 40, and 231 are sometimes collectively referred to as gas pipes.

[0036] A nozzle 234 extends longitudinally from the lower part to the upper part of the reaction tube 203. Furthermore, the nozzle 234 has multiple gas supply holes for distributing and supplying raw material gas. These gas supply holes are located between wafers 200 facing each other via the inner tube 204, supplying processing gas to the wafers 200. A nozzle 233 is similarly provided at a position further inward from the nozzle 234 than the reaction tube 203. This nozzle 233 also has multiple gas supply holes. The nozzle 234, as described above, communicates with the gas piping 10, distributing raw material gas and inert gas from the gas piping 40 connected to the gas piping 10 into the processing chamber 201. Additionally, the nozzle 233, as described above, communicates with the gas piping 11, distributing reaction gas and inert gas from the gas piping 6 connected to the gas piping 11 into the processing chamber 201. Film formation is achieved by alternately supplying processing gas into the processing chamber 201 through nozzles 234 and 233.

[0037] A multi-layered crystal boat 217, in which multiple wafers 200 are placed at equal intervals, is provided inside the inner tube 204. The crystal boat 217 can enter and exit the processing chamber 201 via a crystal boat elevator. In addition, in order to improve the uniformity of processing, a crystal boat rotation mechanism 267, which serves as a rotation unit, is provided for rotating the crystal boat 217. By rotating the crystal boat rotation mechanism 267, the crystal boat 217, which is held in the quartz cover 218, is rotated.

[0038] (Functional structure of controller 321)

[0039] Next, use Figure 2 The controller 321, which is the control unit, will be described.

[0040] The controller 321 is configured as a computer comprising a CPU (Central Processing Unit) 321a, RAM (Random Access Memory) 321b, a storage device 321c, and an I / O port 321d. The RAM 321b, storage device 321c, and I / O port 321d are configured to exchange data with the CPU 321a via an internal bus 321e. An input / output device 322, such as a touch panel, is connected to the controller 321.

[0041] The storage device 321c is configured, for example, as flash memory. Within the storage device 321c, control programs that control the operation of the substrate processing apparatus and process flow describing the substrate processing steps and conditions (described later) are stored in a readable manner. Furthermore, the process flow combines the steps of the substrate processing steps, including the substrate loading step S102 to the substrate unloading step S106 (described later), performed by the controller 321 in a manner that yields a predetermined result. Additionally, the RAM 321b is configured as a storage area (working area) that temporarily holds the programs, data, etc., read from the CPU 321a.

[0042] I / O port 321d is connected to the aforementioned MFCs 32, 33, 41, valves 34, 35, 36, 39, pressure sensor, APC valve 243, vacuum pump 246, thermocouple 550 (as a temperature detection unit), heater 207, piping heater 310 (gas piping heater 22, exhaust piping heater 20), temperature regulator 600, programmable logic controller (PLC) 608, crystal boat rotation mechanism 267, crystal boat lift, etc.

[0043] CPU 321a is configured to read and execute a control program from storage device 321c, and to read the process flow from storage device 321c based on inputs such as operation commands from input / output device 322, which serves as an operation display unit. Furthermore, the CPU321a is configured to control the following actions to comply with the read process flow: flow rate adjustment actions of various gases based on MFC32, 33, and 41; opening and closing actions of valves 34, 35, 36, and 39; opening and closing actions of APC valve 243; pressure adjustment actions based on the pressure sensor of APC valve 243; temperature adjustment actions based on the temperature sensors installed in each area of ​​the heater 207; temperature adjustment actions of the piping heater 310 (gas piping heater 22 and exhaust piping heater 20 respectively) based on the temperature regulator 600 of thermocouple 550; heating start and stop actions of the piping heater 310 based on the temperature regulator 600 of PLC 608; start and stop of vacuum pump 246; rotation and rotation speed adjustment actions of crystal boat 217 based on crystal boat rotation mechanism 267; lifting and lowering actions of crystal boat 217 based on crystal boat elevator, etc.

[0044] Furthermore, the controller 321 can be configured to install the aforementioned program stored in an external storage device (e.g., a USB memory, a memory card, or other semiconductor memory) 323 onto a computer. The storage device 321c and the external storage device 323 constitute a computer-readable recording medium. Hereinafter, they will also be collectively referred to as recording media. When the term "recording medium" is used in this specification, there may be a case where only the storage device 321c is included, a case where only the external storage device 323 is included, or a case where both are included. Additionally, the program can be provided to the computer without using the external storage device 323, but instead using a communication unit such as the Internet or a dedicated line.

[0045] (2) Substrate processing process

[0046] Next, refer to Figure 3 This section outlines a substrate processing step in a substrate processing method that uses a substrate processing apparatus, which is a semiconductor manufacturing apparatus, to process a substrate. This substrate processing step is a step in the semiconductor device manufacturing process, which is a method for manufacturing a semiconductor device. For example, this substrate processing step is used to manufacture a semiconductor device. Furthermore, in the following description, the operation and processing of each component of the substrate processing apparatus are controlled by a controller 321.

[0047] Here, an example is described where a first processing gas (raw material gas) and a second processing gas (reactant gas) are alternately supplied to a wafer 200, which serves as a substrate, to form a film on the wafer 200. Below, an example is described where hexachlorosilane (Si₂Cl₆, abbreviated as HCDS) gas is used as the raw material gas and NH₃ (ammonia) is used as the reactant gas to form a SiN (silicon nitride) film as a thin film on the wafer 200. Furthermore, for example, a predetermined film can be pre-formed on the wafer 200, and a predetermined pattern can also be pre-formed on the wafer 200 or the predetermined film.

[0048] (Substrate handling process S102)

[0049] First, the wafer 200 is loaded into the crystal boat 217 and moved into the processing chamber 201 for the substrate loading process S102.

[0050] (Film forming process S104)

[0051] Next, a film formation process S104, in which a thin film is formed on the surface of wafer 200, is performed. The film formation process sequentially executes the following four steps. Furthermore, between steps 1 and 4, wafer 200 is heated to a predetermined temperature by heater 207. Additionally, gas piping heater 22 heats a portion of gas piping 10 and gas piping 40 to a first specified temperature. The first specified temperature is appropriately set according to the feed gas. In this embodiment, Si2Cl6 gas is used as the feed gas, and therefore, during film formation process S104, it is heated to, for example, 180°C or higher as the first specified temperature. Additionally, exhaust piping heater 20 heats exhaust piping 231 to a second specified temperature during film formation process S104. The second specified temperature is appropriately set to a temperature capable of suppressing the adhesion of reactants (byproducts) generated from the feed gas and reactant gas to the inner surface of exhaust piping 231, for example, 100°C or higher.

[0052] [Step 1]

[0053] In step 1, Si2Cl6 gas is introduced. First, valve 34, located in gas pipe 10, and APC valve 243, located in exhaust pipe 231, are simultaneously opened. This allows Si2Cl6 gas, after flow regulation via MFC 41 from gas supplier 4, to be supplied through gas pipe 10, from the gas supply orifice of nozzle 234 into processing chamber 201, and exhausted from exhaust pipe 231. At this time, gas pipe heater 22 heats gas pipe 10, and exhaust pipe heater 20 heats exhaust pipe 231 to a predetermined temperature. Additionally, the pressure within processing chamber 201 is maintained at a predetermined pressure. Thus, a silicon (Si) thin film is formed on the surface of wafer 200.

[0054] [Step 2]

[0055] In step 2, valve 34 of gas pipe 10 is closed to stop the supply of Si2Cl6 gas. APC valve 243 of exhaust pipe 231 remains open, and vacuum pump 246 vents the processing chamber 201, removing residual gas. Additionally, valve 39 of gas pipe 40 is opened to supply inert gas such as N2 to the processing chamber 201 for purging, expelling residual gas from the processing chamber 201. Furthermore, valve 36 of gas pipe 6 is opened to supply inert gas such as N2, after flow regulation by MFC 33, to the processing chamber 201.

[0056] [Step 3]

[0057] In step 3, NH3 gas is allowed to flow. Simultaneously, valve 35 on pipe 11 and APC valve 243 on exhaust pipe 231 are opened, allowing NH3 gas, after flow regulation via MFC 32 from gas supplier 5, to be supplied to processing chamber 201 through gas supply port of nozzle 233 via gas pipe 11, while simultaneously being discharged from exhaust pipe 231. Additionally, the pressure in processing chamber 201 is adjusted to a predetermined pressure. Through the supply of NH3 gas, the Si thin film formed on the surface of wafer 200 by Si2Cl6 gas undergoes a surface reaction with the NH3 gas, forming a SiN film on wafer 200.

[0058] [Step 4]

[0059] In step 4, the inert gas-based treatment chamber 201 is purged again. Valve 35 on gas pipe 11 is closed to stop the supply of NH3 gas. The APC valve 243 on exhaust pipe 231 remains open, and the treatment chamber 201 is vented by vacuum pump 246 to remove residual gas. Additionally, valve 36 on gas pipe 6 is opened to supply inert gas such as N2, with flow rate regulated by MFC 33, to the treatment chamber 201 for purging. Furthermore, valve 39 on gas pipe 40 is opened to supply inert gas such as N2 to the treatment chamber 201 from gas pipe 40.

[0060] By repeating steps 1 to 4 as a cycle, a SiN film of a predetermined thickness is formed on wafer 200.

[0061] (Substrate removal process S106)

[0062] Next, the wafer 200 on which the SiN film is formed is moved out of the processing chamber 201.

[0063] According to this embodiment, since the feedstock (Si2Cl6) gas is supplied to the processing chamber 201 from the gas pipe 10 while it is heated by the gas pipe heater 22, liquefaction of the feedstock gas can be suppressed, preventing the supply of particulate-containing gas to the processing chamber 201. In other words, the saturated vapor pressure increases with rising temperature, increasing the pressure and quantity supplied without causing liquefaction. Furthermore, the gas pipe 10 is preferably heated from upstream to downstream with a uniform temperature distribution or a temperature that increases gradually towards the downstream. Uneven temperature can cause the gas pipe 10 to be lower than that of the feedstock gas. As a result, there is a risk of liquefaction. When the gas pipe 10 and gas pipe 40 are long, the gas pipe heater 22 can be divided into multiple units.

[0064] Furthermore, in this embodiment, during the repeated cycles of steps 1 to 4, at least while the exhaust pipe heater 20 heats the exhaust pipe 231, the gas pipe heater 22 continuously heats the gas pipe 10 and the gas pipe 40 to maintain the first and second specified temperatures. Alternatively, in this embodiment, during the process execution (from substrate loading step S102 to substrate unloading step S106), temperature control can be performed while the exhaust pipe heater 20 heats the exhaust pipe 231, and at least either the gas pipe 10 or the exhaust pipe 231 can be heated and temperature control performed.

[0065] (3) Structure of the piping heater 310

[0066] Next, the details of the piping heater 310 in this embodiment will be described.

[0067] The piping heater 310 is, for example, a strip heater. Figure 4 (B) and Figure 4 As shown in (C), the pipe heater 310 is used to wind around an exhaust pipe 231 or gas pipe 10, which is made of metal components such as SUS. The pipe heater 310 has a width that is approximately the same as or slightly shorter than the outer perimeter of the gas pipe 10, and can be wound so that the length direction of the pipe heater 310 is aligned with the extension direction of the pipe. Alternatively, it can be wound into a spiral shape relative to the relatively thick exhaust pipe 231. The former winding method makes it easier to achieve a higher seal compared to pipes with a high proportion of straight lines.

[0068] The piping heater 310 is constructed to insulate the wires without using fibrous insulators, for example... Figure 4 As shown in (D), the heating element film 310a, which serves as the heating element, is sandwiched between a fluorocarbon fiber sheet, namely a polytetrafluoroethylene (PTFE) sheet 310b, which is an example of a heat-resistant resin sheet with excellent heat resistance. When the heating temperature is below 200°C, a structure in which a winding heating wire is sandwiched between silicone rubber can also be used. Furthermore, even if glass wool is mixed into the silicone rubber, it can be used without problems as long as no dust is generated.

[0069] The outer periphery of the piping heater 310 is covered and surrounded by insulation material 552. A fastening part 700 is provided at one end of the insulation material 552 to secure one end to the other, either when the insulation material 552 is adjacent to the other end or when the insulation material 552 is wound around the piping heater 310 more than once. The piping heater 310, which uses PTFE, undergoes plastic deformation, but also retains elastic deformation under normal construction conditions. Therefore, to improve the tightness between the piping heater 310 and the gas piping 10, it is preferable to always press or stretch the wound ends from the outer periphery.

[0070] Figure 4 (B) is a cross-sectional view of the piping heater 310 with a thermocouple 550 installed inside. Figure 4 (C) is a cross-sectional view of the piping heater 310 with the thermocouple 550 installed on the outside.

[0071] like Figure 4 (B) and Figure 4 As shown in (C), a thermocouple 550, serving as a temperature detection unit for detecting the temperature of pipes such as exhaust pipe 231 or gas pipe 10, is installed on the inner or outer side of the pipe heater 310. The thermocouple 550 is configured to be detachable from the pipe heater 310 to detect the temperature of the exhaust pipe 231 or gas pipe 10. The thermocouple 550 is installed in a thermally coupled manner by contacting the exhaust pipe 231 or gas pipe 10. Furthermore, only one thermocouple 550 is provided corresponding to each pipe heater 310. That is, one thermocouple 550 is installed in each of the exhaust pipe heater 20 and the gas pipe heater 22. In the case of multiple exhaust pipe heaters 20, multiple thermocouples 550 are correspondingly provided.

[0072] Then, the controller 321 adjusts the operating amount (output value) representing the power output to each pipe heater 310 based on the temperature (measured value) detected by the thermocouple 550 of each exhaust pipe 231 or gas pipe 10, so that the temperature (measured value) of the exhaust pipe 231 or gas pipe 10 follows its respective predetermined set value.

[0073] Thus, in the case of a structure where the thermocouple 550 is separate from the pipe heater 310, the thermocouple 550 may sometimes detach from the pipe heater 310 when it is installed on the exhaust pipe 231 or the gas pipe 10. Furthermore, even when installed on the inner circumference, the installation of the thermocouple 550 may sometimes be omitted from the pipe heater 310. Alternatively, the correspondence between the pipe heater 310 and the thermocouple 550 may sometimes be incorrect. If temperature control continues under such conditions, the pipe heater 310 will be continuously supplied with power at 100% output, causing it to overheat.

[0074] In addition, such as Figure 4 (B) and Figure 4 As shown in (C), since the thermocouple 550 is installed inside the piping heater 310 and inside the insulation material 552, when the piping heater 310 is installed or removed during maintenance of the substrate processing apparatus, even if the thermocouple 550 is forgotten to be installed or its position is misaligned, it cannot be visually confirmed. For example, if the piping heater 310 is rewound after piping replacement or cleaning, even if the position of the thermocouple 550 changes, it is impossible to directly confirm the change in the measured temperature value (actual temperature) inside the piping. Therefore, the temperature detected by the thermocouple 550 is treated as the measured temperature value inside the piping.

[0075] Temperature control is performed based on the measured temperature value in a manner that follows the set temperature. Therefore, the temperature detected by thermocouple 550 must also be controlled to follow the set temperature. Thus, thermocouple 550 is only controlled when its position shifts. Therefore, if only the measured temperature value is monitored, even if thermocouple 550 is disconnected from the piping heater 310, thermocouple 550 detects the surrounding temperature. Even if the temperature inside the gas piping reaches the set temperature, it is considered that the set temperature has not been reached, and controller 321 continues to supply power to piping heater 310 at 100% output (operational quantity).

[0076] In order to solve the above problems, the inventors discovered that abnormalities such as the separation of thermocouple 550 from pipe heater 310 or forgetting to install thermocouple 550 are detected. The power supply to pipe heater 310 is automatically turned off to prevent excessive heating of pipe heater 310, thereby protecting pipe heater 310 and surrounding components from burn-out.

[0077] Figure 5 This is a block diagram illustrating the structure of the temperature regulator 600 used in this embodiment.

[0078] The temperature regulator 600 includes at least a temperature regulating unit 602 and a power output control unit 604, which serves as a power output controller.

[0079] The temperature is input to the temperature control unit 602 by the measured temperature detected by the thermocouple 550. Then, the temperature control unit 602 performs PID (Proportional-Integral-Differential) control on the deviation between the measured temperature detected by the thermocouple 550 and the stored set temperature (target temperature) of the piping heater 310, generating an operating quantity indicating the amount of power to be supplied to the piping heater 310. The temperature control unit 602 then automatically adjusts the power output control unit 604 to eliminate the deviation between the measured temperature and the set temperature.

[0080] An AC power supply 606, serving as an alternating current power source, is connected to the power output control unit 604. The power output control unit 604 adjusts the input AC power supply according to the operating amount from the temperature regulation unit 602 and outputs it to the piping heater 310. As the power output control unit 604, a solid-state relay (SSR) can be used, for example, in series with the circuit including the AC power supply 606 and the piping heater 310.

[0081] As an example, the temperature control unit 602 outputs an operating quantity as a continuous quantity, and the power output control unit 604 generates a binary signal with a duty cycle proportional to the operating quantity to control the switching on and off of the semiconductor relay. This type of control is called cyclic control or time-sharing proportional control. The binary signal can also be generated within the temperature controller 600. Alternatively, the power output control unit 604 can also include a thyristor, which is controlled by generating a trigger signal synchronously with the AC power supply, providing a conduction angle corresponding to the operating quantity. This type of control is called phase control (conduction angle control).

[0082] The temperature regulator 600 is communicatively connected to the PLC (Programmable Logic Controller) 608, which acts as a host controller, via RS-485 or similar means. The PLC 608 is also communicatively connected to the controller 321.

[0083] A heater switch 610 is connected to the PLC 608. The PLC 608 controls the start and stop of heating of the exhaust pipe 231 or gas pipe 10 based on the control of the temperature regulator 600. In addition to being a physical switch, the heater switch 610 can also be a logic switch whose state is changed by the controller 321.

[0084] The PLC 608 sends a control start signal to the temperature regulator 600 upon activation of the heater switch 610. Then, the PLC 608 obtains from the temperature regulator 600 the measured temperature of the thermocouple 550 (temperature information) and the operating quantity information indicating the amount of power to be supplied to the piping heater 310. Additionally, the PLC 608 monitors whether the temperature of the piping heater 310 deviates significantly from the target value.

[0085] Furthermore, after the heating of the exhaust pipe 231 or gas pipe 10, controlled by the temperature regulator 600, begins, the PLC 608 repeatedly acquires operational quantity information indicating the amount of electricity that should be supplied to the pipe heater 310. Then, the PLC 608 accumulates the time when the acquired operational quantity is at its maximum value (100%), and if the accumulated time exceeds a threshold, it controls the temperature regulator 600 to stop the heating of the exhaust pipe 231 or gas pipe 10.

[0086] Furthermore, after the heating of the exhaust pipe 231 or gas pipe 10 begins under the control of the temperature regulator 600, the PLC 608 repeatedly acquires the temperature information detected by the thermocouple 550. It accumulates the time during which the operation is at its maximum value (100%) and the deviation between the temperature detected by the thermocouple 550 and the initial temperature at the start of heating of the exhaust pipe 231 or gas pipe 10 is less than a predetermined threshold. Then, if the accumulated time exceeds the threshold, the PLC 608 controls the temperature regulator 600 to stop the heating of the exhaust pipe 231 or gas pipe 10.

[0087] For example, the power output control unit 604 responds to the cut-off signal from the PLC 608, forcibly disconnecting the aforementioned binary signal and trigger signal. This is achieved by using a logical AND operation on the generated binary signal, trigger signal, and cut-off signal. Alternatively, unlike SSRs used for temperature control, an SSR controlled by a cut-off signal is connected in series in the circuit. Thus, the power supply to the piping heater 310 is disconnected regardless of the operating amount from the temperature regulating unit 602.

[0088] Multiple sets of piping heaters 310, thermocouples 550, and temperature controllers 600 can be installed. In this case, a single cut-off unit, such as an electromagnetic relay located on the AC power supply 606 side, can be used for multiple piping heaters 310. Furthermore, the PLC 608 can set target values ​​in each temperature controller 600, and if heating of the gas piping 310 is stopped under the control of at least one temperature controller 600, the power supply output control unit 604 can disconnect all power to the multiple piping heaters 310 to achieve a controlled stop.

[0089] Next, use Figure 6The operation of PLC608 is explained below. During the period when the heater switch 610 inputs an on signal, PLC608 performs the following processing according to the ladder program held internally.

[0090] In step S10, when the PLC608 receives an on signal through the heater switch 610, it sends a control start signal to the temperature regulator 600.

[0091] In step S12, when a control start signal is sent from PLC 608, the power output control unit 604 starts to output power to the piping heater 310 to heat the exhaust piping 231 and the gas piping 10.

[0092] In step S14, PLC608 obtains the measured temperature detected by thermocouple 550 from temperature regulator 600 as temperature information.

[0093] In step S16, the PLC 608 remains in standby mode until a preset time has elapsed. Alternatively, processing after step S18 may be skipped. After the standby time has elapsed, in step S18, it is determined whether the temperature deviation between the measured temperature (initial temperature) at the start of control in step S10 and the measured temperature after the preset time is above a threshold. That is, the PLC 608 determines whether the deviation between the measured temperature detected by the thermocouple 550 and the temperature at the start of heating of the exhaust pipe 231 or gas pipe 10 is less than a predetermined threshold. Additionally, during the standby time, sufficient time (e.g., 1 minute) is required for the temperature detected by the normal thermocouple 550 to change due to heating by the pipe heater 310.

[0094] Then, in step S18, if it is determined that the temperature deviation is above the threshold ("Yes" in step S18), in step S20, the power supply by the power output control unit 604 continues, the process returns to step S18, and the temperature control monitoring by the temperature regulator 600 continues.

[0095] Furthermore, in step S18, if it is determined that the temperature deviation is less than the threshold (in step S18, this is "No"), in step S22, it is determined whether the state of the power output control unit 604 having an operation quantity of 100% has lasted for more than the threshold time. To perform this process, step S22 may include: a sub-step S22a that determines whether the operation quantity in the obtained operation quantity information is 100%, and if it is 100%, updates (increases) the accumulated time; and a sub-step S22b that compares the accumulated time with the threshold time. Additionally, in the case of thermocouple 550 detachment, the operation quantity will inevitably saturate to its maximum value after the standby time. Therefore, based on the assumption that the operation quantity is 100%, the determination to update the accumulated time can be omitted. In this case, it is sufficient to perform the determination of whether the operation quantity is 100% only once at a time point where the accumulated time is more than the threshold time.

[0096] Then, in step S22, if it is determined that the operation amount is 100% (maximum value) and a threshold time has elapsed ("Yes" in step S22), in step S24, the power supply is cut off by the power output control unit 604. That is, the temperature regulator 600 is controlled to stop the heating of the exhaust pipe 231 or the gas pipe 10, and the power supply to the pipe heater 310 is cut off.

[0097] In addition, in step S22, if it is determined that the operation amount is 100% (maximum value) and has not exceeded the threshold time (in step S22, it is "No"), the process returns to step S18 and continues to perform temperature control based on temperature regulator 600.

[0098] That is, if the temperature deviation between the instant the heater switch 610 is pressed and the temperature measurement value after pressing is above a threshold, power output to the piping heater 310 continues, and temperature control is maintained. Then, the power output to the piping heater 310 is cut off when the accumulated time exceeds the threshold, provided that the temperature deviation between the instant the heater switch 610 is pressed and the temperature measurement value after pressing is less than the threshold and the output value is 100% (maximum value). Furthermore, even if the thermocouple 550 detaches during temperature control, the process can branch from step S18 to step S22, ultimately cutting off the power output.

[0099] PLC608, in addition to Figure 6In addition to the actions shown, it can also monitor the relationship between the operating quantity (output value) of the piping heater 310 and the measured temperature of the thermocouple 550, detect phenomena that may affect the actual temperature inside the piping, and issue an alarm. That is, if the measured temperature does not rise even after a preset time, the temperature deviation is less than a threshold, or the operating quantity of the piping heater 310 remains at 100% (maximum value) for more than a threshold time, it can determine that the thermocouple 550 is faulty (open circuit) or misaligned in its installation position as the main cause of the abnormality. Furthermore, if overheating of the piping heater 310 is detected, or if an abnormality (short circuit) of the thyristor (SCR) or an excessively low temperature of the piping heater 310 is detected, it can determine that the abnormality is due to an open circuit of the piping heater 310 or an abnormality (open circuit) of the SCR. Then, if an abnormality is determined, the power supply to the piping heater 310 installed in the substrate processing apparatus is stopped. That is, the excessive temperature rise of the piping heater 310 can be suppressed.

[0100] According to this embodiment, abnormal temperature changes in the gas piping 10 can be detected. Therefore, by performing recovery processes such as rewinding the piping heater 310, liquefaction of the processing gas caused by a decrease in the temperature of the gas piping 10 can be suppressed, preventing it from accumulating at the furnace opening. As a result, the impact on film thickness can be suppressed, thereby preventing a decrease in the processing quality of the substrate.

[0101] According to this embodiment, abnormal temperature changes in the exhaust pipe 231 can be detected. Therefore, by performing recovery processes such as rewinding the pipe heater 310, for example, by reducing the temperature of the exhaust pipe 231, the adhesion of byproducts to the exhaust pipe 231 can be suppressed. As a result, the cleaning cycle can be extended.

[0102] In the above embodiments, an example of using a belt heater as a piping heater 310 has been described, but this disclosure is not limited thereto. Piping heaters that can be installed and removed from piping, such as jacketed heaters, combinations of jacketed heaters and belt heaters, combinations of aluminum blocks and jacketed heaters, and rubber heaters, can also be appropriately applied.

[0103] Furthermore, in the above embodiment, an example of the process of forming a SiN film on wafer 200 was described, but this disclosure is not limited thereto, and can be appropriately applied when forming, modifying or etching films using piping heater 310.

[0104] Furthermore, in the above embodiments, an example of film formation using a batch-type vertical apparatus, i.e., a substrate processing apparatus, that processes multiple substrates at a time has been described. However, this disclosure is not limited to this. Film formation using a single-piece substrate processing apparatus that processes one or more substrates at a time can also be appropriately applied.

[0105] The above describes various typical embodiments of the present invention, but this disclosure is not limited to these embodiments and can be used in appropriate combinations.

[0106] (4) Examples

[0107] Figure 7 (A) and Figure 7 (B) is a graph showing the time-varying output value (operating value), temperature of the belt heater, and measurement temperature of the thermocouple 550 when the thermocouple 550 detaches from the belt heater, which is an example of a piping heater 310. Additionally, Figure 7 (A) and Figure 7 The right vertical axis of (B) represents the amount of temperature rise (the difference between the current temperature and the initial temperature).

[0108] like Figure 7 As shown in (B), in a comparative example using a board processing apparatus that does not include a PLC 608 and a temperature regulator 600, if the thermocouple detaches from the belt heater while the gas piping is heated to 180°C, temperature control of the belt heater continues even with the thermocouple detached. The gas piping temperature is not reflected in the belt heater, and the belt heater continues to be powered at 100% output (operational value), causing its temperature to rise to 180°C. Therefore, the belt heater becomes abnormally overheated.

[0109] In contrast, in this embodiment using the substrate processing apparatus of this embodiment, such as Figure 7 As shown in (A), if the thermocouple detaches from the belt heater when the gas piping is heated to 180°C, after the heater switch is turned on, the PLC608 obtains the measured temperature of the thermocouple (temperature information) and the operation amount of the belt heater (operation amount information) from the temperature regulator 600. If the temperature deviation between the measured temperature of the thermocouple at the moment the heater switch is pressed and 1 minute after pressing is less than 2°C, and the operation amount of the belt heater is 100% (maximum value) and lasts for more than 1 minute, it is detected that the position and state of the thermocouple are abnormal, and the power supply to the belt heater is cut off at time t.

[0110] That is, if the thermocouple installed in the belt heater detaches, the abnormality of the belt heater is detected, and the power supply to the belt heater is cut off. This prevents abnormal heating and overheating of the piping heater. Furthermore, the maximum value of the operating quantity used by the temperature regulator 600 is not limited to 100% as always with the power output control unit 604 on; it can be set to any value between 0% and 100%.

[0111] Symbol Explanation

[0112] 10 Gas Piping

[0113] 200 wafers (substrate)

[0114] 201 Processing Room

[0115] 231 exhaust piping

[0116] 310 Piping Heater

[0117] 321 controller

[0118] 600 temperature regulator

[0119] 608 PLC.

Claims

1. A substrate processing apparatus characterized by comprising: Possessing: a pipe heater that heats a gas pipe that supplies a gas to a processing chamber that processes a substrate; a temperature detecting section that detects a temperature of the gas pipe; a temperature regulator that outputs an operation amount indicating an electric power that should be supplied to the pipe heater in accordance with the temperature detected by the temperature detecting section, and performs control to bring the temperature of the gas pipe close to a target value; and a higher-level controller that controls start and stop of heating of the gas pipe under the control of the temperature regulator, the higher-level controller repeatedly acquires the temperature detected by the temperature detecting section after the start of heating of the gas pipe under the control of the temperature regulator, accumulates a time at which the operation amount becomes a maximum value and a deviation of the temperature detected by the temperature detecting section from the temperature at the start of heating of the gas pipe is less than a predetermined threshold value, and in a case where the accumulated time is equal to or more than the threshold value, controls the temperature regulator to stop heating of the gas pipe.

2. The substrate processing apparatus according to claim 1, characterized in that the pipe heater is a tape heater in which a wire is insulated without using a fiber-based insulator.

3. The substrate processing apparatus according to claim 1, characterized in that the temperature detecting section is installed so as to be thermally coupled to the gas pipe by being in contact with the gas pipe, and only one temperature detecting section is provided in correspondence with the pipe heater.

4. The substrate processing apparatus according to claim 1, characterized in that the substrate processing apparatus further possesses a power supply output controller that turns on or off supply of electric power to the pipe heaters under control of the higher-level controller, in a case where the target value is set to each of the temperature regulators, and heating of the gas pipe is stopped in control of at least one of the temperature regulators, the higher-level controller sets off supply of electric power to all of the pipe heaters by the power supply output controller, thereby performing the stop of the control.

5. The substrate processing apparatus according to claim 4, characterized in that a plurality of sets of the pipe heater, the temperature detecting section, and the temperature regulator are provided, each of the temperature regulators controls a power supply output from the power supply output controller so as to supply electric power corresponding to the operation amount to the corresponding pipe heater by conduction angle control or on-off control.

6. The substrate processing apparatus according to claim 5, characterized in that the power supply output controller possesses a thyristor or a semiconductor relay that is inserted in series into a circuit including an alternating-current power supply and the pipe heater.

7. The substrate processing apparatus according to claim 1, characterized in that the temperature detecting section is configured to be separable from the pipe heater.

8. The substrate processing apparatus according to claim 1 or 7, characterized in that the pipe heater has a width corresponding to an outer periphery of the gas pipe, and a length direction of the pipe heater is set to follow the gas pipe.

9. The substrate processing apparatus according to claim 1 or 7, wherein the pipe heater has a structure in which a heat generating body thin film is sandwiched by heat resistant resin sheets.

10. A method of manufacturing a semiconductor device, characterized by comprises the steps of: processing a substrate in a processing chamber; heating, by a pipe heater, a gas pipe that supplies a gas to the processing chamber; detecting, by a temperature detecting section, a temperature of the gas pipe; based on the detected temperature, outputting an operation amount indicating an electric power that should be supplied to the pipe heater to bring the temperature of the gas pipe close to a target value; and after the start of heating of the gas pipe, acquiring the operation amount and the temperature detected by the temperature detecting section, accumulating a time during which the operation amount becomes a maximum value and a deviation of the temperature detected by the temperature detecting section from a temperature at the start of heating of the gas pipe is smaller than a predetermined temperature threshold value, and in a case where the accumulated time is equal to or more than the threshold value, stopping the heating of the gas pipe.

11. A substrate processing method, characterized by, comprises the steps of: processing a substrate in a processing chamber; heating, by a pipe heater, a gas pipe that supplies a gas to the processing chamber; detecting, by a temperature detecting section, a temperature of the gas pipe; based on the detected temperature, outputting an operation amount indicating an electric power that should be supplied to the pipe heater to bring the temperature of the gas pipe close to a target value; and after the start of heating of the gas pipe, acquiring the operation amount and the temperature detected by the temperature detecting section, accumulating a time during which the operation amount becomes a maximum value and a deviation of the temperature detected by the temperature detecting section from a temperature at the start of heating of the gas pipe is smaller than a predetermined temperature threshold value, and in a case where the accumulated time is equal to or more than the threshold value, stopping the heating of the gas pipe.

12. A recording medium storing a program that causes a computer included in a substrate processing apparatus to execute the steps of: processing a substrate in a processing chamber; heating, by a pipe heater, a gas pipe that supplies a gas to the processing chamber; detecting, by a temperature detecting section, a temperature of the gas pipe; based on the detected temperature, outputting an operation amount indicating an electric power that should be supplied to the pipe heater to bring the temperature of the gas pipe close to a target value; and after the start of heating of the gas pipe, acquiring the operation amount and the temperature detected by the temperature detecting section, accumulating a time during which the operation amount becomes a maximum value and a deviation of the temperature detected by the temperature detecting section from a temperature at the start of heating of the gas pipe is smaller than a predetermined temperature threshold value, and in a case where the accumulated time is equal to or more than the threshold value, stopping the heating of the gas pipe.

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