Heater life prediction method, heating apparatus, and heater life prediction program

Abstract

To provide: a heater life prediction method capable of previously preventing unexpected breaking of a heater; a heat treatment device; and a heater life prediction program.SOLUTION: A heater life prediction method for predicting heater life in a semiconductor manufacturing apparatus including a treatment chamber for treating a substrate and a heater for heating the substrate conveyed into the treatment chamber comprises calculating a resistance change amount being a difference between the resistance of the heater and the initial value of the resistance or a resistance change rate obtained by dividing the resistance change amount by the initial value in the step of subjecting the heater to fixed output control during the treatment to different substrates to predict heater life on the basis of the calculated resistance change amount or resistance change rate.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] The present invention relates to a heater life prediction method, a heat treatment apparatus, and a heater life prediction program.

Background Art

[0002] A resistance heater (hereinafter also referred to as a heater) mainly composed of carbon or the like used in an environment with a hydrogen (H2) gas atmosphere deteriorates due to the progress of a chemical reaction between the heater and a reactive gas and often finally breaks. When the heater provided in a film forming apparatus for forming a film on the surface of a substrate breaks unexpectedly, various problems such as the occurrence of defective products and the response to sudden apparatus recovery occur. As a result, the productivity of the film forming apparatus is significantly reduced. Therefore, it is required to establish a method capable of preventing an unexpected breakage of the heater.

[0003] To prevent an unexpected breakage of the heater, for example, in Patent Documents 1 and Patent Documents 2, techniques for predicting the life of the heater using the resistance value of the heater have been proposed.

[0004] That is, in Patent Document 1, a system has been proposed that reads a continuous change in the resistance value of the heater when the heater is energized and issues an alarm when the read resistance value exceeds a preset threshold value (see, for example, paragraph 0029). However, the steps of wafer processing are composed of a wafer heating step, a cooling step, and a film forming step in which conditions can change for each wafer. The temperature of the heater changes throughout the steps of wafer processing, and the resistance value of the heater also fluctuates. Therefore, it is difficult to set an appropriate threshold value for heater breakage for all steps when the heater is energized.

[0005] Furthermore, Patent Document 2 predicts the heater's lifespan by determining the difference between the measured resistance value of the heater and the initial or theoretical value of the heater's resistance, and comparing this difference with a predetermined threshold value that serves as an indicator of heater failure (see, for example, paragraphs 0063 and 0064). However, calculating the theoretical value of the heater's resistance requires determining the temperature coefficient of resistance at an arbitrary temperature of the heater, and thermocouples are used to measure the heater's temperature (see, for example, paragraph 0023). Installing thermocouples in the film deposition apparatus incurs extra costs, and the thermocouples may also become a source of metal contamination within the apparatus. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2009-245978 [Patent Document 2] Japanese Patent Publication No. 2011-108596 [Overview of the project] [Problems that the invention aims to solve]

[0007] The object of the present invention is to provide a heater life prediction method, a heating apparatus, and a heater life prediction program that can prevent unexpected heater rupture. [Means for solving the problem]

[0008] A heater life prediction method according to one aspect of the present invention is: The invention relates to a semiconductor manufacturing apparatus comprising a processing chamber in which substrates are processed, and a heater for heating the substrates brought into the processing chamber, and includes a method for predicting the lifespan of the heater. The prediction of the heater's lifespan is as follows: During the process in which the heater is controlled to a constant output between the processing on different substrates, the resistance change amount, which is the difference between the resistance value of the heater and the initial value of the resistance, or the resistance change rate obtained by dividing the resistance change amount by the initial value, is calculated. Based on the calculated resistance change amount or resistance change rate, the lifespan of the heater is predicted. To prepare for it.

[0009] In the heater life prediction method described above, the heater life may be predicted based on the relationship between the amount of resistance change or the rate of resistance change and a preset threshold.

[0010] The heater life prediction method described above may further include notifying the user that the heater is nearing the end of its life.

[0011] In the heater life prediction method described above, the step in which constant output control is performed may be at least one of the following: a film formation step in which a film is formed on the substrate; a cooling step in which the temperature of the substrate is lowered; and a removal step in which the substrate is removed from the processing chamber.

[0012] A heating apparatus according to one aspect of the present invention is: The processing room where the substrates are processed, A heater for heating the substrate that has been brought into the processing chamber, The system includes a life prediction unit that predicts the lifespan of the heater, The life prediction unit, During the process in which the heater is controlled to a constant output between the processing on different substrates, the resistance change amount, which is the difference between the resistance value of the heater and the initial value of the resistance, or the resistance change rate obtained by dividing the resistance change amount by the initial value, is calculated. The lifespan of the heater is predicted based on the calculated resistance change amount or resistance change rate.

[0013] A heater life prediction program according to one aspect of the present invention is: On the computer, A procedure for predicting the lifespan of a heater in a heat treatment apparatus comprising a processing chamber in which a substrate is processed, and a heater for heating the substrate brought into the processing chamber, During the process in which the heater is controlled at a constant output between the treatments on different substrates, calculate a resistance change amount which is the difference between the resistance value of the heater and the initial value of the resistance value, or a resistance change rate obtained by dividing the resistance change amount by the initial value. Predict the life of the heater based on the calculated resistance change amount or resistance change rate. Execute a procedure including these steps.

Advantages of the Invention

[0014] According to the present invention, unexpected breakage of the heater can be prevented.

Brief Description of the Drawings

[0015] [Figure 1] It is a diagram showing a film forming apparatus according to the first embodiment. [Figure 2] It is a diagram showing the wafer temperature and the skin power of the entire wafer processing step. [Figure 3] It is a graph showing the time change of the wafer temperature for each run in the loading step and the temperature rising step. [Figure 4] It is a graph showing the change in the resistance value according to the number of runs for each heater which is a comparative example. [Figure 5] It is a graph showing the change in the amount of resistance increase according to the number of runs for each heater of the present embodiment. [Figure 6] It is a graph showing the change in the resistance increase rate according to the number of runs for each heater of the present embodiment. [Figure 7] It is a graph showing the change in the resistance value according to the number of runs for each heater which is a comparative example. [Figure 8] It is a graph showing the change in the amount of resistance increase according to the number of runs for each heater of the present embodiment. [Figure 9] It is a graph showing the change in the resistance increase rate according to the number of runs for each heater of the present embodiment. [Figure 10] It is a flowchart showing a heater life prediction method according to the present embodiment.

Embodiments for Carrying Out the Invention

[0016] Embodiments of the present invention will be described below with reference to the drawings. These embodiments are not intended to limit the present invention.

[0017] Figure 1 shows a film deposition apparatus 1 according to this embodiment. As shown in Figure 1, the film deposition apparatus 1 comprises a chamber (film deposition chamber) 2, which is an example of a processing chamber; a gas supply unit 3; a raw material discharge unit 4; a susceptor 5; a rotating unit 6; a heater 7; a heater drive unit 8; a gas discharge unit 9; an exhaust mechanism 10; a radiation thermometer 11; and a control unit 12, which is an example of a life prediction unit.

[0018] Chamber 2 performs a film deposition process on a wafer W, which is an example of a substrate. Chamber 2 is a single-wafer chamber that deposits films onto wafers W one at a time. Wafer W is, for example, a compound semiconductor wafer containing compound semiconductors such as SiC and GaN. It is not limited to compound semiconductor wafers; wafer W may also be, for example, a silicon wafer containing single-crystal silicon. Chamber 2 has a shape (for example, a cylindrical shape) that can accommodate the wafer W to be deposited. Inside Chamber 2 are a susceptor 5, a heater 7, and part of a rotating part 6. Chamber 2 is provided with a gate valve (not shown) whose opening and closing is controlled by a control unit 12. By opening the gate valve, a transport robot (not shown) can load and unload wafers W into and out of Chamber 2.

[0019] The gas supply unit 3 supplies raw material gas to the wafer W in the chamber 2. The gas supply unit 3 has multiple gas storage units 3a for individually storing multiple gases, multiple gas pipes 3b connecting these gas storage units 3a to the raw material discharge unit 4, and multiple gas valves 3c for adjusting the flow rate of gas through these gas pipes 3b. Each gas valve 3c is connected to the corresponding gas pipe 3b. The multiple gas valves 3c are controlled by the control unit 12. The actual piping can take on multiple configurations, such as connecting multiple gas pipes, branching one gas pipe into multiple gas pipes, or combining branching and connecting gas pipes.

[0020] The raw material discharge section 4 is located at the top of the chamber 2. The raw material gas supplied from the gas supply section 3 is discharged into the chamber 2 through the raw material discharge section 4. The raw material gas (process gas) discharged into the chamber 2 is supplied to the surface of the wafer W, thereby forming the desired film on the wafer W surface. The type of raw material gas used is not particularly limited. The raw material gas can be changed depending on the type of film to be deposited.

[0021] A shower plate 4a is provided on the bottom side of the raw material discharge section 4. The shower plate 4a can be made of a metal material such as stainless steel and aluminum alloy. Gases from multiple gas pipes 3b are mixed in the raw material discharge section 4 and supplied into the chamber 2 through the gas nozzle 4b of the shower plate 4a. Multiple gas flow paths may be provided in the raw material discharge section 4 to separate multiple types of gas and supply them to the wafer W in the chamber 2 using nozzles or the like.

[0022] The structure of the raw material discharge section 4 should be selected considering factors such as the in-plane uniformity of the deposited film, the consumption efficiency of the supplied raw material gas, reproducibility, and manufacturing costs. However, it is not particularly limited as long as it satisfies these requirements, and known structures can be used as appropriate.

[0023] The susceptor 5 supports the wafer W within the chamber 2. The susceptor 5 is located on the upper part of the rotating part 6 that holds and rotates the susceptor 5. The susceptor 5 has a structure that supports the wafer W by placing it in a counterbore provided on the inner circumference of the susceptor 5. In the example shown in Figure 1, the susceptor 5 has an annular shape with an opening in the center, but it is not limited to this, and the susceptor 5 may have a substantially flat shape without an opening. It may also be a combination of multiple parts.

[0024] Heater 7 heats the susceptor 5 and wafer W. Heater 7 heats the wafer W that has been brought into the chamber 2. Heater 7 is a resistance heating type heater made of carbon or the like.

[0025] The heater drive unit 8 drives the heater 7 by supplying power to it. For example, the heater drive unit 8 supplies a power supply voltage to the heater 7, causing current to flow through the heater 7 and generating heat. The specific form of the heater drive unit 8 is not particularly limited as long as it can drive the heater 7. For example, the heater drive unit 8 may have a transformer, a primary circuit connected to the primary side of the transformer, and a secondary circuit connected to the secondary side of the transformer. The primary circuit has a thyristor, and for example, a commercial power supply voltage may be applied to the primary circuit. The transformer may perform voltage conversion between the AC voltage on the primary circuit side and the AC voltage on the secondary circuit side. The heater may be connected to the secondary circuit. A voltmeter and an ammeter may also be connected to the secondary circuit. The voltmeter may measure the voltage applied to the heater, and the ammeter may measure the current flowing through the heater. The measured values ​​from the voltmeter and ammeter may be supplied to the control unit 12.

[0026] The gas discharge section 9 discharges the gas from inside the chamber 2. The exhaust mechanism 10 exhausts the gas from the gas discharge section 9. The exhaust mechanism 10 exhausts the reactant gas from inside the chamber 2 via the gas discharge section 9 and controls the pressure inside the chamber 2 to a desired level using the exhaust valve 10a and the vacuum pump 10b.

[0027] The radiation thermometer 11 measures the temperature of the wafer W. The radiation thermometer 11 is located on the upper surface of the raw material discharge section 4. The radiation thermometer 11 irradiates the wafer W with light from a light source (not shown), receives the reflected light from the wafer W, and measures the reflected light intensity of the wafer W. The radiation thermometer 11 also receives thermal radiation light from the film growth surface of the wafer W and measures the thermal radiation light intensity. In Figure 1, only one radiation thermometer 11 is shown, but multiple radiation thermometers 11 may be placed on the upper surface of the raw material discharge section 4 to measure the temperature at multiple locations on the film growth surface of the wafer W (for example, the center and the outer edge).

[0028] A light-transmitting window (not shown) is provided on the upper surface of the raw material discharge section 4. Light from the light source of the radiation thermometer 11, as well as reflected light and thermal radiation light from the wafer W, pass through the light-transmitting window. The light-transmitting window can take any shape, such as a slit, rectangular, or circular shape. A material that is transparent to the wavelength range of light measured by the radiation thermometer 11 is used for the light-transmitting window. For example, when measuring temperatures from room temperature to about 1500°C, it is preferable to measure the wavelength of light in the visible to near-infrared region, in which case quartz or similar material is preferably used for the light-transmitting window. The measurement result of the wafer W temperature by the radiation thermometer 11 is used by the control unit 12, which functions as a temperature controller, to control the power supply to the heater 7 by the heater drive unit 8 based on the temperature of the wafer W.

[0029] The control unit 12 includes a computer (not shown) that centrally controls the film deposition apparatus 1, and a memory unit (not shown) that stores process control programs and equipment history. The control unit 12 controls the gas supply unit 3, the rotation mechanism of the rotating unit 6, the exhaust mechanism 10, and the heating of the wafer W by the heater 7 by executing the process control program stored in the memory unit. The control unit 12 controls the heater 7 to maintain the temperature measured by the radiation thermometer 11 at a desired temperature, or to maintain a predetermined constant output.

[0030] The control unit 12 further predicts the lifespan of the heater 7 and, if necessary, notifies the user when its lifespan is nearing its end.

[0031] The following explains how to predict the lifespan of heater 7.

[0032] Figure 2 shows the wafer temperature and apparent power for the entire wafer W processing step. As shown in Figure 2, the wafer W processing consists of a series of processing steps: loading step, heating step, film deposition step, cooling step, and unloading step. The loading step is the step of loading the wafer W to be deposited into the chamber 2. The heating step is the step of raising the temperature of the wafer W by heating the wafer W with a heater 7. The film deposition step is the step of depositing a film on the wafer W. For example, in the film deposition step, a chemical reaction occurs on the heated surface of the wafer W with the raw material gas supplied into the chamber 2, forming an epitaxial film on the surface of the wafer W. The cooling step is the step of lowering the temperature of the wafer W by setting the output of the heater 7 to zero or very low. The unloading step is the step of unloading the wafer W from the chamber 2 by controlling the output of the heater 7 to a constant level.

[0033] When the present inventors processed multiple wafers W in succession using a film deposition apparatus having the same configuration as shown in Figure 1, it was confirmed that variations in the resistance value of the heater 7 occurred between film deposition processes (runs) of different wafers W, depending on the processing step (i.e., loading step, heating step, film deposition step, cooling step, and unloading step).

[0034] In the loading and heating steps, as shown in Figure 3, the temperature of the wafer W at the same time differs between the first film deposition process and the subsequent film deposition processes for wafers transported while the chamber 2 is kept warm. This is thought to be because the temperature of the reflector and insulation material in the chamber 2 is high due to the heating process from approximately 800°C to 1600°C in the preceding film deposition process. The difference in the temperature of the wafer W at the same time between the first film deposition process and subsequent film deposition processes suggests that the temperature of the heater 7 is also different at the same time. Since the resistance value of the heater depends on the heater temperature, the variation in the resistance value of the heater 7 is thought to be due to the difference in the temperature of the heater 7 at the same time.

[0035] Furthermore, variations in the resistance values ​​of other heaters can be attributed to individual differences in wafers. For example, differences in wafer warping, wafer carrier concentration, or their in-plane distribution may lead to contact between the wafer and the susceptor, variations in the infrared absorption coefficient of the wafer, or both. This can result in variations in the heater output during wafer temperature control via the temperature controller. Therefore, variations in the resistance value of heater 7 occur during the film deposition step when wafer temperature control of wafer W is applied.

[0036] In the cooling step, the temperature of the wafers W behaves the same way across wafers W. However, since the heater 7 is turned OFF to cool the wafers, the apparent power of the heater 7 becomes 0 [kVA] or a very small value, making it impossible to calculate the resistance value of the heater 7, or significantly reducing the accuracy of the calculation. On the other hand, in the unloading step, the heater 7 is output controlled to maintain a constant output, resulting in small temperature variations between film deposition processes (runs) of different wafers W, and thus small fluctuations in the resistance value of the heater 7. In other words, it is preferable to predict the heater's lifespan in the unloading step, where the output is controlled to a constant level.

[0037] Figures 4 to 6 show the changes in heater resistance, resistance increase, and resistance increase rate, respectively, calculated during the discharge step. Figure 4 is a graph showing the change in resistance according to the number of runs (processing cycles) for each heater, as a comparative example. Figure 5 is a graph showing the change in resistance increase according to the number of runs for each heater according to this embodiment. Figure 6 is a graph showing the change in resistance increase rate according to the number of runs for each heater according to this embodiment. Figures 4 to 6 all show data up to just before the heater breaks, and the horizontal axis is the relative value with the number of runs just before breakage set to 1.

[0038] As shown in Figure 4, when using the heater's resistance value, variations in the initial resistance values ​​between different heaters result in variations in the heater's resistance value just before failure. Thus, when simply using the heater's resistance value to predict heater life, it is not possible to set a unique threshold because the initial resistance value differs due to factors such as dimensional tolerances during heater manufacturing. On the other hand, as shown in Figures 5 and 6, when using the resistance increase amount or resistance increase rate, the influence of variations in the initial resistance values ​​between different heaters can be eliminated, and an appropriate threshold for the resistance increase amount or resistance increase rate that leads to heater failure (lifetime) can be set. Furthermore, by comparing the change in the resistance increase amount or resistance increase rate with the threshold, it is possible to predict the number of runs (heater life) at which heater failure occurs. Note that before reaching the end of life, for example, as shown in Figure 6, a caution level threshold of 0.113 and an alarm level threshold of 0.127 can be set. The threshold setting criteria here is based on the value of the case with the smallest resistance increase rate immediately before rupture (the value of Case 3 in this example), with the caution level set at 85% and the alarm level at 95%. These thresholds can be arbitrarily set by the user, either by setting them lower to account for the risk of heater rupture or higher to reduce production costs. By setting the thresholds in two stages, caution and warning levels, sufficient warnings can be given to the user. In this way, by setting an appropriate heater rupture threshold, the lifespan of the heater can be predicted.

[0039] Furthermore, in the case of a heater composed of a conductive thin film (e.g., pyrolytic graphite and pyrolytic boron nitride) deposited on the surface of a substrate, the initial resistance value can easily change by 10% or 20% due to variations in the thickness of the thin film, and the resistance change may change by 1.1 times or 1.2 times. In such cases, as shown in Figures 7 and 8, the changes in resistance value and resistance increase amount differ depending on the case. However, as shown in Figure 9, by using the change in the resistance increase rate, the influence of individual differences in heaters caused by the above can be eliminated, and an appropriate heater failure threshold can be set. For example, the threshold for the caution level can be set to 0.163, and the threshold for the alarm level to 0.182.

[0040] Figure 10 is a flowchart showing the heater life prediction method according to this embodiment. Based on the above findings, in this embodiment, the control unit 12 calculates the resistance increase rate during the discharge step and predicts the life of the heater 7 based on the calculated resistance increase rate. The specific method for predicting the life of the heater 7 is as follows.

[0041] Figure 10 is a flowchart showing the heater life prediction method according to this embodiment. First, as shown in Figure 10, the control unit 12 detects the start of the wafer removal step based on the progress of the wafer W processing (step S1).

[0042] After detecting the start of the discharge step, the control unit 12 calculates the resistance value of the heater 7 (step S2).

[0043] After calculating the resistance value of the heater 7, the control unit 12 calculates the resistance increase amount by calculating the difference between the calculated resistance value of the heater 7 and the initial value of the heater 7's resistance value that was calculated in advance (step S3).

[0044] After calculating the resistance increase, the control unit 12 calculates the resistance increase rate by dividing the resistance increase by the initial resistance value of the heater 7 (step S4). Note that steps S2 to S4 may be performed in a single step.

[0045] After calculating the resistance increase rate, the control unit 12 determines whether the resistance increase rate has exceeded a preset first threshold for the first time (step S5). The first threshold is, for example, the caution level threshold described above.

[0046] When the resistance increase rate exceeds the first threshold for the first time (Step S5: Yes), the control unit 12 predicts that the heater 7 is nearing the end of its lifespan and performs a first notification process to the user (Step S6). The control unit 12 performs the first notification process using, for example, an alarm sound source or display device (not shown) connected to the control unit 12. The first notification process may include, for example, sounding the alarm sound source to alert the user by voice that the heater 7 is nearing the end of its lifespan, or displaying on the display device that the heater 7 is nearing the end of its lifespan to alert the user.

[0047] On the other hand, if the resistance increase rate does not exceed the first threshold (Step S5: No "<First threshold"), the control unit 12 detects the start of the discharge step again and then repeats the calculation of the resistance value of the heater 7 (Steps S2 to S4).

[0048] After performing the first notification process, the control unit 12, after detecting the start of the next unloading step, determines in step S5 whether the resistance increase rate has exceeded a preset second threshold (step S7), assuming that it is not the first time the resistance increase rate has exceeded the first threshold (step S5: No ">>not the first threshold"). The second threshold is a threshold that is larger than the first threshold, for example, the alarm level threshold described above.

[0049] If the resistance increase rate exceeds a second threshold (step S7: Yes), the control unit 12 predicts that the heater 7 is nearing the end of its lifespan and performs a second notification process to the user (step S8). The control unit 12 performs the second notification process using, for example, an alarm sound source or display device (not shown) connected to the control unit 12. In the second notification process, it is conceivable that the end of the heater 7's lifespan is nearing by making an audible sound or displaying an indication that the heater 7 is closer to breaking. In the second notification process, the power supply to the heater 7 may be stopped from the heater drive unit 8.

[0050] On the other hand, if the resistance increase rate does not exceed the second threshold (step S7: No), the control unit 12 detects the start of the discharge step again and then repeats the calculation of the resistance value of the heater 7 (steps S2 to S4).

[0051] As described above, according to this embodiment, the resistance increase rate is calculated in the discharge step where output control to the heater 7 is performed, and based on the calculated resistance increase rate, the lifespan of the heater 7 can be predicted with high accuracy, with little influence from the dimensional tolerances and individual differences in the deterioration tendencies of the heater 7. This prevents unexpected breakage of the heater 7 and suppresses the occurrence of defective products due to heater breakage and downtime caused by sudden equipment repairs.

[0052] This embodiment is not limited to the example described above, but can be applied to various modifications as shown below.

[0053] (First variation) If the heater degradation trend does not change, the lifespan of the heater 7 may be predicted based on the resistance increase calculated in the discharge step. In this case, as in the embodiment, multiple thresholds may be set as thresholds for the resistance increase and the user may be notified. As in the embodiment, the lifespan of the heater 7 can be predicted with high accuracy.

[0054] (Second variation) Under certain conditions, resistance calculation may be performed at a step other than the discharge step. For example, if there is a period in the film deposition step during which the heater is controlled to a constant output, the lifespan of the heater 7 can be predicted during the constant output control period based on the resistance increase rate or resistance increase amount of the heater 7 calculated in the film deposition step. In this case as well, the lifespan of the heater 7 can be predicted with high accuracy, similar to the embodiment.

[0055] (Third variation) Furthermore, if the heater 7 is controlled to a constant output between processing different wafers W, for example by gradually decreasing the heater output instead of reducing it to zero during the cooling step, the lifespan of the heater 7 can be predicted based on the resistance increase rate or resistance increase amount of the heater 7 calculated during the cooling step. In this case as well, the lifespan of the heater 7 can be predicted with high accuracy, similar to the embodiment. In addition, by gradually decreasing the output of the heater 7, the furnace environment can be changed slowly, and the load on the wafer W can be suppressed. This reduces the deformation of the wafer W caused by thermal stress due to temperature differences on the wafer surface.

[0056] The embodiments described above are presented as examples and are not intended to limit the scope of the invention. The embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. Although a film deposition apparatus has been described as an embodiment, any heat treatment apparatus equipped with a resistance heating heater can be applied, and these embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of Symbols]

[0057] 1 film deposition apparatus, 2 chambers, 7 heaters, 12 control unit

Claims

1. The invention relates to a semiconductor manufacturing apparatus comprising a processing chamber in which substrates are processed, and a heater for heating the substrates brought into the processing chamber, and includes a method for predicting the lifespan of the heater. The prediction of the heater's lifespan is as follows: During the unloading process in which the substrate is unloaded from the processing chamber between the processing steps for different substrates, the power supplied to the heater is output controlled so that the apparent power remains constant. During this period, the resistance increase rate is calculated by dividing the difference between the resistance value of the heater and the initial value of the resistance by the initial value. When the calculated resistance increase rate exceeds any of the multiple thresholds for the warning level and alarm level for the first time, the heater's lifespan is predicted by providing a notification to the user corresponding to the exceeded threshold. A heater life prediction method that includes the following features.

2. The lifespan of the aforementioned heater is The heater life prediction method according to claim 1, further comprising predicting the life based on the relationship between the resistance increase rate and a preset threshold.

3. The processing room where the substrates are processed, A heater for heating the substrate that has been brought into the processing chamber, The system includes a life prediction unit that predicts the lifespan of the heater, The life prediction unit, During the unloading process in which the substrate is unloaded from the processing chamber between the processing steps for different substrates, the power supplied to the heater is output controlled so that the apparent power remains constant. During this period, the resistance increase rate is calculated by dividing the difference between the resistance value of the heater and the initial value of the resistance by the initial value. When the calculated resistance increase rate exceeds any of the multiple thresholds for the warning level and alarm level for the first time, the heater's lifespan is predicted by providing a notification to the user corresponding to the exceeded threshold. Heat treatment device.

4. On the computer, A procedure for predicting the lifespan of a heater in a heat treatment apparatus comprising a processing chamber in which a substrate is processed, and a heater for heating the substrate brought into the processing chamber, During the unloading process in which the substrate is unloaded from the processing chamber between the processing steps for different substrates, the power supplied to the heater is output controlled so that the apparent power remains constant. During this period, the resistance increase rate is calculated by dividing the difference between the resistance value of the heater and the initial value of the resistance by the initial value. When the calculated resistance increase rate exceeds any of the multiple thresholds for the attention level and alarm level for the first time, the user is notified of the threshold that was exceeded, thereby predicting the lifespan of the heater. A heater life prediction program for performing a procedure that includes the following.

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