JP4878801B2 - Substrate processing apparatus and semiconductor device manufacturing method - Google Patents

Description

  The present invention relates to a substrate processing apparatus, and more particularly to an apparatus for effectively controlling the temperature in a processing chamber when a temperature sensor fails.

  In the substrate processing apparatus, the temperature of the zone-divided furnace is controlled during execution of a processing sequence for processing a substrate. Temperature control in the furnace is performed by controlling the power value to the heater based on the temperature measured by the temperature sensor. If the temperature sensor fails during execution of the processing sequence, the power supply to the heater in the zone where the failure has occurred is set to zero based on the concept of fail-safe.

  If a temperature sensor failure occurs in the lower temperature drop step or substrate pull-out step in the second half of a series of processing sequences, there is a possibility that process processing such as film formation processing has ended normally. If it occurs during the process including the main heating process, even if the process of setting the power supply to the heater to zero is performed, the process process does not end normally, and the substrate at the end of the process sequence becomes defective. There is a case. Therefore, there has been a demand for a technique that can reduce the occurrence of defective products even when the temperature sensor fails.

Therefore, conventionally, two adjacently arranged temperature sensors are provided so as to be switchable, and when one of the temperature sensors breaks down, the other temperature sensor is used as an alternative to one of the temperature sensors, and the other temperature sensor is measured. An apparatus has been proposed in which the temperature is controlled so as to coincide with the set temperature set for one of the temperature sensors (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 10-270454

However, in the technique described in Patent Document 1 described above, the two temperature sensors are arranged close to each other, but the measurement locations are different. Therefore, as an alternative to one temperature sensor, the measurement temperature of the other temperature sensor is used as it is as the set temperature. When the control is performed, a difference occurs between the measured temperature and the set temperature of one of the temperature sensors that the temperature control is originally intended to perform, and it is difficult to continue the stable temperature control.
An object of the present invention is to provide a substrate processing apparatus capable of stably maintaining temperature control even when a temperature sensor fails.

  According to a first aspect of the present invention, there is provided a processing chamber for processing a substrate, a heating unit for heating the processing chamber, a first temperature sensor disposed outside the processing chamber for measuring the temperature of the heating unit, and the first temperature. A second temperature sensor that is disposed nearer to the substrate than the sensor and measures the temperature in the processing chamber; and a control unit that controls the heating unit based on the temperatures measured by the first and second temperature sensors. And when the processing chamber is heated by the heating unit, the control unit performs a first calculation based on a deviation between a set temperature and a temperature measured by the second temperature sensor, and the first calculation A substrate processing apparatus that performs a second calculation based on a deviation between a result and a temperature measured by the first temperature sensor, and controls the heating unit based on the second calculation result, wherein the second temperature Sensor cannot measure temperature normally In addition, the temperature difference is obtained and stored based on the temperature measured by the first and second temperature sensors when the temperature is stabilized at the set temperature, and the control is performed so that the substrate is processed in the processing chamber. When the second temperature sensor cannot measure the temperature normally while the means is controlling the heating means, the control means detects the deviation between the temperature measured by the second temperature sensor and the set temperature. In place of performing the first calculation based on the above, the set temperature is corrected by the stored temperature difference, and the second calculation is performed based on the deviation between the correction result and the temperature measured by the first temperature sensor. And the heating means is controlled based on the second calculation result.

  According to the present invention, before the second temperature sensor breaks down, the temperature difference is obtained and stored based on the temperatures measured by the first and second temperature sensors when the temperature is stabilized at the set temperature. Then, the set temperature is corrected based on the stored temperature difference, and this correction result is used in place of the first calculation result, so that the second measurement is performed based on the deviation between the temperature measured by the second temperature sensor and the set temperature. It is possible to perform a calculation that is substantially equivalent to the calculation of 1. Therefore, even when the second temperature sensor fails during the process and temperature measurement by the second temperature sensor becomes impossible, the heating means is controlled using the usable first temperature sensor. And stable temperature control can be performed.

  Here, the time before the second temperature sensor cannot measure the temperature normally refers to a timing at which the obtained temperature difference can be used as a correction result capable of continuing control of the heating means. In the preceding process that is performed prior to processing the substrate, the control unit controls the heating unit to stabilize the temperature at the set temperature during the substrate processing in the processing chamber, and when this temperature is stable (temperature stabilization Time). In addition to the time when the temperature is stabilized, it may be just before the failure of the second temperature sensor, or when the substrate processing is started in the processing chamber.

  According to a second aspect of the present invention, there is provided a processing chamber for processing a substrate, a heating unit for heating the processing chamber, a first temperature sensor disposed outside the processing chamber for measuring the temperature of the heating unit, and the first temperature. A second temperature sensor that is disposed nearer to the substrate than the sensor and measures the temperature in the processing chamber; a third temperature sensor that detects abnormal heating of the heating means; and the first and second temperature sensors Control means for controlling the heating means based on the respective measured temperatures, and when the processing chamber is heated by the heating means, the control means measures a set temperature and a temperature measured by the second temperature sensor. The first calculation is performed based on the deviation of the first calculation, the second calculation is performed based on the deviation between the first calculation result and the temperature measured by the first temperature sensor, and the heating is performed based on the second calculation result. It is a substrate processing apparatus that controls the means. Before the temperature of the first temperature sensor cannot be measured normally, a temperature difference is obtained and stored based on the temperatures measured by the first and third temperature sensors when the temperature is stabilized at the set temperature. In the main processing for processing a substrate in the processing chamber, when the control unit is controlling the heating unit, the control unit is not able to measure the temperature normally. Is measured by the third temperature sensor based on the stored temperature difference, instead of performing a second calculation based on a deviation between the first calculation result and the temperature measured by the first temperature sensor. In the substrate processing apparatus, the temperature is corrected, a second calculation is performed based on the correction result and the first calculation result, and the heating unit is controlled based on the second calculation result.

  According to the present invention, before the failure of the first temperature sensor, the temperature difference is obtained and stored based on the temperatures measured by the first and third temperature sensors when the temperature is stabilized at the set temperature. Then, the set temperature is corrected by the stored temperature difference, and this correction result is used in place of the temperature to be measured by the failed first temperature sensor. It is possible to perform a pseudo but substantially equivalent operation to the second operation performed based on the deviation from the operation result of 1. Therefore, even if the first temperature sensor fails during the process and temperature measurement by the first temperature sensor becomes impossible, the control of the heating means is performed using the usable third temperature sensor. And stable temperature control can be performed.

  Also in the present invention, the time before the first temperature sensor can not measure the temperature normally refers to the timing at which the obtained temperature difference can be used as a correction result capable of continuing control of the heating means. In the preceding process that is performed prior to processing the substrate in the processing chamber, the control unit controls the heating unit to stabilize the temperature at the set temperature at the time of substrate processing in the processing chamber, and when this temperature is stable ( (When temperature is stable). In addition to the time when the temperature is stabilized, it may be just before the failure of the first temperature sensor, or when the substrate processing is started in the processing chamber.

  A third invention is characterized in that, in the first or second invention, the heating means is divided into a plurality of zones to divide and heat the processing chamber, and the control means is provided for each zone. A substrate processing apparatus. Since the zone-divided heating means can be controlled for each zone, temperature control in the processing chamber can be continuously controlled more stably.

  According to a fourth invention, in the third invention, before the temperature sensor becomes unable to measure the temperature normally, a temperature difference obtained from the temperature measured by each temperature sensor is stored for each zone, and this memory is stored. The substrate processing apparatus is characterized in that the means is a lookup table that stores the temperature difference for each zone. Since a desired temperature difference can be obtained by a look-up table, the speed of control can be increased.

  According to the present invention, stable temperature control can be continued even when a temperature sensor fails.

Embodiments of the present invention will be described below.
As a substrate processing apparatus, for example, there is a semiconductor manufacturing apparatus that manufactures a semiconductor device. Among them, a vertical CVD furnace that collectively processes a plurality of substrates using a chemical reaction (CVD reaction) will be described with reference to the drawings. Here, in any of the drawings and description, a vertical furnace is used as an example, but the present invention can be applied to other furnaces.

  FIG. 7 shows a structural example of the vertical CVD furnace of the embodiment. The vertical CVD furnace shown in FIG. 7 mainly includes a reaction tube 104 that forms a processing chamber 100 therein, and a heater 101 that serves as a heating means for heating the inside of the reaction tube 104. A boat 106 having a substrate 103 for heat treatment is inserted into the reaction tube 104.

  The temperature control system for controlling the temperature of the vertical CVD furnace includes an external thermocouple 102 as a first temperature sensor, an internal thermocouple 105 as a second temperature sensor, and an overheat as a third temperature sensor. And a protective thermocouple 109. Furthermore, a device operation unit 108 for designating a set temperature, a temperature controller 107 for obtaining an operation amount Z (power value) for the heater 101, and a power regulator for supplying power to the heater 101 according to an output value of the temperature controller 107. 110. The temperature controller 107, the apparatus operation unit 108, and the power regulator 110 described above constitute a control unit 111.

  The heater 101 is divided into zones in order to control the furnace temperature with higher accuracy. For example, in the case of a four-zone division, the zones are arranged in the order of U and CU from the top along the axial direction of the reaction tube 104. , CL, and L zones. Corresponding to each zone of the divided heater 101, an external thermocouple 102, an internal thermocouple 105, and an overheat protection thermocouple 109 are arranged separately in the vertical direction.

  The external thermocouple 102 is disposed outside the processing chamber 100 and in the vicinity of the heater 101, and measures the temperature of the heater 101 by measuring the temperature in the vicinity of the heater 101. The internal thermocouple 105 is disposed closer to the substrate 103 than the external thermocouple 102, for example, in the reaction tube 104 as in the illustrated example, and measures the temperature in the processing chamber 100 (also simply referred to as the furnace temperature). The overheat protection thermocouple 109 is disposed in the vicinity of the heater 101, and detects abnormal heating of the heater 101 in order to protect the apparatus by forcibly shutting off the heater power supply.

  The purpose of temperature control in this vertical CVD furnace is to make the measurement temperature of the internal thermocouple 105 installed in the vicinity of the substrate 103 for heat treatment coincide with the set temperature Y. In the temperature control system described above, the temperature controller 107 sets the set temperature Y to the temperature controller 107 from the apparatus operation unit 108, and the temperature controller 107 sets the external thermocouple so that the measured temperature of the internal thermocouple 105 matches the set temperature Y. 102, the operation amount (power value) Z to be supplied to the heater 101 is calculated based on the measured temperature of the internal thermocouple 105 (and the overheat protection thermocouple 109), and the calculation result is output to the power regulator 110. Then, electric power corresponding to the output value is supplied to the heater 101.

As shown in FIG. 8, the temperature controller 107 constitutes a cascade control loop. The cascade control loop includes a first adder 401 that outputs a deviation (first deviation) between the set temperature Y and the measured temperature from the internal thermocouple 105, and a PID calculation according to the output of the first adder 401. Then, the first PID adjustment unit 402 that indicates the value that the measured temperature from the external thermocouple 102 should follow, and the deviation between the output of the first PID adjustment unit 402 and the measured temperature from the external thermocouple 102 ( A second adder 403 that outputs a second deviation), a second PID adjustment unit 404 that performs a PID calculation according to the output of the second adder 403, and instructs the operation amount Z to the heater 101; Consists of.
Note that FIG. 8 describes only one zone, but when four zones are divided, a similar configuration exists for each zone. In FIG. 8, the power regulator 110 is omitted for convenience, but is omitted in FIGS. 1 and 4 described below.

  As shown in FIG. 9, the device operation unit 108 is used for an operator to confirm operation information of the device and make various settings, and an operation screen unit 201 for saving a recipe (processing sequence information). It is comprised from the recipe preservation | save part 202, the communication part 203 between temperature controllers which transmits / receives data between the temperature controllers 107, and the control part 204 which controls these.

  The device operation unit 108 transmits the set temperature and parameter settings set by the operator to the temperature controller 107, receives data such as temperature data and heater power value, and operates the received data as device information. They are displayed on the screen unit 201 or stored in the storage area 205 provided in the control unit 204.

Next, a processing sequence used in the vertical CVD furnace will be described. FIG. 10 shows a flowchart of an example of a process performed in a vertical CVD furnace, and FIG. 11 shows an outline of temperature changes in the furnace at that time.
In step S1, the pre-heat treatment to stabilize at a relatively low temperature T ₀ of the temperature in the furnace. Here, the boat 106 has not yet been inserted into the furnace. In step S2, a process of inserting the boat 106 into the furnace (boat loading) is performed. In step S3, a process (ramp up) for gradually increasing the temperature in the furnace from the set temperature T ₀ to a set temperature T ₁ higher than the temperature T ₀ for performing a process such as a film forming process on the substrate 103 is performed. Do. To step S4 in the substrate 103 to a temperature in the furnace in order to perform the process treatment conduct the heat treatment to stabilize at the set temperature T ₁ of the at substrate processing. In step S5, a process (ramp down) for gradually lowering the temperature in the furnace from the set temperature T ₁ to the relatively low set temperature T ₀ again is performed. In step S6, a process (boat unloading) is performed to pull out the boat 106 on which the process-processed substrate 103 is mounted from the furnace.

  The above processing sequence is executed after the operator sets from the operation screen unit 201 of the apparatus operation unit 108 as needed and saves it in the recipe storage unit 202. Normally, the processing from step S1 to step S6 is repeatedly performed, but the external thermocouple 102 or the internal thermocouple 105 may fail during execution of the processing sequence, and temperature measurement by the internal thermocouple 105 may become impossible. is there. Usually, in such a case, information necessary for temperature control is lost and control cannot be continued, so that the zone where the failure has occurred is shifted to a safe direction, that is, the operation amount Z for the heater 101 is set to 0%. I do.

However, if the above failure phenomenon occurs in step S5 (temperature drop) or step S6 (substrate pullout) in FIG. 11, there is a possibility that process processing such as film formation processing has ended normally. If it occurs between step S1 (maintenance of set temperature T ₀ ) and step S4 (maintenance of set temperature T ₁ ), the process ends normally even if the operation amount Z to the heater 101 is set to 0%. In some cases, the substrate at the end of the processing sequence becomes a defective product.
Therefore, the present inventor has devised the following substrate processing apparatus having a cascade control loop that can reduce the occurrence of defective products even when the temperature sensor fails.

[First Embodiment]
FIG. 1 is a configuration diagram of a cascade control loop showing a first embodiment of such a substrate processing apparatus. The basic configuration of the cascade control loop is the same as in FIG.
8 differs from the configuration of FIG. 8 in that the temperature of the internal thermocouple 105 becomes impossible when the processing chamber 100 is heated by the heater 101, that is, during temperature control, and the internal thermocouple 105 cannot measure the temperature. When the controller 107 determines, the internal thermocouple 105 is removed from the control loop, and a value obtained by correcting the temperature difference stored in the stable temperature difference table 406 as a lookup table in addition to the set temperature is calculated as the first calculation result. As an alternative, the configuration is incorporated in the control loop.

  Here, it is conceivable that the heater 101 is controlled so that the measured temperature of the external thermocouple 102 becomes the set temperature Y specified from the apparatus operation unit 108. However, the external thermocouple 102 and the internal thermocouple 105 Since the measurement location is different, when the measurement temperature of the external thermocouple 102 is controlled to be the set temperature Y designated from the device operation unit 108 as it is, the measurement temperature of the internal thermocouple 105 that is originally desired to be temperature controlled and the setting are set. A large discrepancy occurs between the temperature Y and the quality of the process process may be reduced.

  Therefore, after removing the internal thermocouple 105 from the control loop, the third adder 405 adds the temperature difference read from the stable temperature difference table 406 to the set temperature Y specified from the apparatus operation unit 108. Then, the set temperature Y is corrected, and the correction result is used as a substitute for the first calculation result, and the measured temperature of the external thermocouple 102 is added to the second adder 403 to obtain the second deviation. Based on the second deviation, the second calculation is performed by the second PID adjustment unit 404, and the heater 101 is controlled so that the set temperature is corrected based on the second calculation result (operation amount Z). It is configured to do.

  Note that the stable temperature difference table 406 provided in the storage area 205 (see FIG. 9) of the apparatus operation unit 108 is stored in advance, that is, prior processing or temperature data acquisition performed before processing a substrate in the processing chamber. Therefore, when performing the above-described processing sequence in a simulated manner without using a substrate or process gas, the temperature controller 107 controls the heater 101 so that the inside of the processing chamber 100 is pre-heated during the substrate processing and the main heating processing. The temperature is stabilized at each set temperature Y set in the time processing sequence, and when this temperature is stable, the temperature difference obtained between the external thermocouple 102 and the internal thermocouple 105 is different for each zone. And stored for each set temperature. FIG. 2 shows an example of the stable temperature difference table 406 storing such temperature differences.

Next, the operation of the control means 111 including the cascade control loop will be described with reference to FIG.
In the preceding process performed before processing the substrate 103 in the processing chamber 100, the control unit 111 controls the heater 101 (step 301), and the processing chamber 100 is preheated during the substrate processing, the main heating process, and the like. It is determined whether or not the temperature is stabilized at each set temperature T set in the processing sequence (step 303), and when the temperature is stabilized, the external thermocouple 102 and the internal thermocouple 105 measure each. A temperature difference is obtained from the measured temperature and stored (step 305).

  In the main processing for actually processing the substrate 103 in the processing chamber 100, when the control unit 111 controls the heater 101 (step 307), it is determined whether or not the internal thermocouple 105 is normal (step 309). If normal, a first calculation is performed based on the first deviation between the temperature measured by the internal thermocouple 105 and the set temperature Y (step 311). On the other hand, when the temperature of the internal thermocouple 105 cannot be measured normally, the control unit 111 switches to performing the first calculation based on the first deviation between the temperature measured by the internal thermocouple 105 and the set temperature Y. Then, the set temperature Y is corrected by the temperature difference corresponding to the same set temperature stored in the stable temperature difference table 406 (step 313), and the second deviation between the correction result and the temperature measured by the external thermocouple 102 is obtained. Based on the second calculation result (step 314), the heater 101 is controlled based on the second calculation result until the present process is completed (step 315).

  Thus, when the internal thermocouple 105 fails, the temperature of the external thermocouple 102 is adjusted to a set temperature corrected by the temperature difference between the external thermocouple 102 and the internal thermocouple 105 when the temperature in the processing chamber 100 is stabilized. By controlling the measured temperature, the temperature control can be stably continued so that the measured temperature of the internal thermocouple 105 becomes the original set temperature Y in a pseudo manner.

  The internal thermocouple 102 and the external thermocouple 105 described above are divided into upper and lower portions corresponding to the respective heaters 101 divided into a plurality of zones, and the internal thermocouple corresponding to one of the zones is provided. When the temperature cannot be measured due to disconnection or failure, the pair 105 has the same configuration as the cascade control loop of the embodiment for each zone, so the temperature cannot be measured by the failed internal thermocouple 105. Although only the zone is controlled to correct the set temperature based on the stored temperature difference, the internal thermocouple 105 corresponding to the other zone can normally measure the temperature, so the temperature controller 107 of the control means 111 is shown in FIG. A cascade control loop is formed, and the first deviation is determined based on the first deviation between the temperature measured by the internal thermocouple 105 and the set temperature. It controls to the operation.

[Second Embodiment]
FIG. 4 shows a configuration diagram of a cascade control loop showing the second embodiment of the present invention. The basic configuration is the same as in FIG. 1 except that the external thermocouple 102 is controlled when the external thermocouple 102 fails during temperature control and temperature measurement by the external thermocouple 102 becomes impossible. The configuration is such that the measurement temperature of the overheat protection thermocouple 109 is incorporated into the control loop as an alternative to the measurement temperature of the external thermocouple 102 by removing from the loop.

  Here, since the measurement location is different between the external thermocouple 102 and the overheat protection thermocouple 109, when the measurement temperature of the overheat protection thermocouple 109 is directly controlled as an alternative to the measurement temperature of the external thermocouple 102, the temperature control is performed. It may become unstable and cause a reduction in process processing quality.

Therefore, the temperature difference read from the stable temperature difference table 408 is added to the measured temperature of the overheat protection thermocouple 109 by the fourth adder 407 to correct the measurement temperature of the overheat protection thermocouple 109. The second adder 403 adds the correction result to the first calculation result calculated by the first PID adjustment unit 402 to obtain a second deviation, and the second PID is based on the second deviation. The adjustment unit 404 performs a second calculation, and the heater 101 is controlled based on the second calculation result (operation amount Z).
The stable temperature difference table 408 includes an external thermocouple 102 and an overheat protection thermocouple when the temperature is stabilized at each set temperature set in the processing sequence such as the preheating process and the main heating process in advance. The temperature difference from 109 is stored for each zone and for each set temperature. FIG. 5 shows an example of a stable temperature difference table 406 storing such temperature differences.

Next, the operation of the control means 111 including the cascade control loop will be described with reference to FIG.
In the preceding process performed prior to processing the substrate 103 in the processing chamber 100, the control unit 111 controls the heater 101 (step 601), and the processing chamber 100 is preheated during the substrate processing, the main heating process, and the like. It is determined whether or not the temperature is stable with respect to each of the set temperatures set in the processing sequence (step 603). When the temperature is stable, the external thermocouple 102 and the internal thermocouple 105 respectively A temperature difference is obtained from the measured temperature and stored (step 605).

  In the main processing for actually processing the substrate 103 in the processing chamber 100, when the control unit 111 controls the heater 101 (step 607), the first of the temperature measured by the internal thermocouple 105 and the set temperature Y is set. The first calculation is performed based on the deviation (step 609), and then it is determined whether the external thermocouple 102 is normal (step 611). If normal, the first calculation result and the temperature measured by the external thermocouple are determined. The second calculation is performed based on the second deviation (step 613). On the other hand, when the temperature of the external thermocouple 102 cannot be measured normally, the control unit 111 performs the second calculation based on the second deviation between the first calculation result and the temperature measured by the external thermocouple. Instead, the temperature measured by the overheat protection thermocouple 109 is corrected based on the temperature difference corresponding to the same set temperature stored in the stable temperature difference table 406, and the second value is calculated based on the correction result and the first calculation result. (Correction calculation) is performed (step 614), and the heater 101 is controlled based on the correction calculation result until this processing is completed (step 615).

  As a result, even if the external thermocouple 102 fails, the temperature obtained by adding the value of the stable temperature difference table 408 to the measured temperature of the overheat protection thermocouple 109 is substituted for the measured temperature of the external thermocouple 102. As a result, temperature control can be continued stably.

  Note that the internal thermocouple 102, the external thermocouple 105, and the overheat protection thermocouple 109 described above are provided in a vertically divided manner corresponding to each of the heaters 101 divided into a plurality of zones. When the external thermocouple 102 corresponding to one zone becomes unable to measure temperature due to disconnection or failure, the same configuration as the cascade control loop of the embodiment exists for each zone. Only the zone in which the temperature cannot be measured by the pair 102 is controlled to correct the measurement of the overheat protection thermocouple 109 by the stored temperature difference, but the external thermocouple 102 corresponding to the other zone can normally measure the temperature. The temperature controller 107 of the control means 111 constitutes a cascade control loop shown in FIG. It controls to the second operation based on a second difference between the temperature measured in 102.

  As described above in detail, according to the present invention, even when a temperature sensor breaks down and the temperature measurement by the temperature sensor becomes impossible during execution of the processing sequence, the usable temperature sensor is used. Therefore, the generation of defective products can be reduced by ending the process such as the film forming process normally.

Hereinafter, the first embodiment will be described with a specific example. The main process here and the preceding process performed prior to the main process in order to acquire the temperature difference are included in both the preliminary heating process and the main heating process.
First, prior processing is performed, and the temperature difference between the external thermocouple 102 and the internal thermocouple 105 when the temperature is stabilized is acquired in the stable temperature difference table 406. Since the temperature difference may be different for each zone to be controlled, the temperature difference is acquired according to the zone of the processing sequence to be executed. For example, in the processing sequence of FIG. 11, when the set temperature T ₀ in the preheating process is 300 ° C. and the set temperature T ₁ in the main heating process is 500 ° C., two points of 300 ° C. and 500 ° C. are acquired. As an acquisition method, for example, in the case of the set temperature T ₀ , the timing at which the state within 300 ° C. ± 1 ° C. continues for 20 minutes can be used as a correction result that allows the heater 101 to continue control. The control means 111 determines.
(Measurement temperature of external thermocouple 102: 290 ° C., for example) − (measurement temperature of internal thermocouple 105, eg 300 ° C.) = − 10 ° C.
Is stored in the stable temperature difference table 406 as a temperature difference when stable at 300 ° C. Similarly, the temperature difference at the time of stabilization is stored for each zone. Similarly, in the case of the set temperature T ₁ , the temperature difference when stabilized at 500 ° C. is stored for each zone.

This process is executed after the preceding process. If the internal thermocouple 105 fails during execution of step S1 (maintaining the set temperature T ₀ ) in the processing sequence of FIG. 11, the internal thermocouple 105 is removed from the control loop. And the corrected set temperature,
Set temperature Y = (T ₀ : 300 ° C.) + (Temperature difference when stable at 300 ° C. in stable temperature difference table: −10 ° C.)
= 290 ° C
For this, the measured temperature of the external thermocouple 102 is controlled. Thereby, it becomes possible to control the measured temperature of the internal thermocouple 105 in a pseudo manner so that the set temperature becomes Y = T ₀ : 300 ° C.

Similarly, if the internal thermocouple 105 fails during the execution of S4 in the processing sequence of FIG. 11, the temperature difference when the stable temperature difference table of 500 ° C. is set to the set temperature Y = T ₁ : 500 ° C. Is added to control the measured temperature of the external thermocouple 102.
As described above, even when the internal thermocouple 105 fails during the processing sequence of the preheating process and the main heating process, the temperature control can be stably continued.

Hereinafter, the second embodiment will be described with a specific example.
First, prior processing is performed before the processing sequence is executed, and the temperature difference between the external thermocouple 102 and the overheat protection thermocouple 109 when the temperature is stabilized is acquired in the stable temperature difference table 408. The temperature difference may be different depending on the temperature range to be controlled, and is acquired according to the temperature range of the processing sequence to be executed. For example, in the processing sequence of FIG. 11, when T ₀ is 300 ° C. and T ₁ is 500 ° C., the data are acquired at two points of 300 ° C. and 500 ° C., respectively. The acquisition method is, for example, when a state within 300 ° C. ± 1 ° C. continues for 20 minutes.
(Measurement temperature of external thermocouple 102: 290 ° C., for example)-(Measurement temperature of overheat protection thermocouple 109: 285 ° C., for example)
= + 5 ° C
Is stored in the stable temperature difference table 408 as a temperature difference when stable at 300 ° C. Similarly, it is stored for each zone. Similarly, the temperature difference when stabilized at 500 ° C. is stored for each zone.
The stable temperature difference table can be acquired simultaneously with the temperature difference between the external thermocouple 102 and the internal thermocouple 105 and the temperature difference between the external thermocouple 102 and the overheat protection thermocouple 109 described above.

Next, this processing which is a processing sequence is executed. If the external thermocouple 102 fails during the execution of S1 in the processing sequence of FIG. 11, the external thermocouple 102 is removed from the control loop,
(Measured temperature of overheat protection thermocouple 109 285 ° C.) + (Temperature difference when stable at 300 ° C. of stable temperature difference table: + 5 ° C.)
= 290 ° C
Is used as an alternative to the measured temperature of the external thermocouple 102.

  Similarly, when the external thermocouple 102 fails during the execution of S4 in the processing sequence of FIG. 11, the temperature difference at the stable temperature difference table of 500 ° C. is added to the measured temperature of the overheat protection thermocouple 109. Is used as an alternative to the measured temperature of the external thermocouple 102 to control.

  This makes it possible to continue temperature control stably even when the external thermocouple 102 fails during execution of the preheating process or the main heating process.

  In the description of the embodiment described above, the temperature difference between the thermocouples when the temperature is stable is acquired in advance, and this acquired temperature difference is used for correction when one of the thermocouples fails. The difference acquisition timing is not limited to this, and it is only necessary to use the temperature difference acquired before the temperature sensor cannot measure the temperature normally as a correction result that allows the heater control to be continued when the thermocouple fails. For example, it can be used to correct the temperature difference between the thermocouples just before the failure, or to correct the temperature difference between the thermocouples at the start of the processing sequence (at the start of substrate processing in the processing chamber). It is also possible to use it.

It is a block diagram of the cascade control loop (temperature controller) which shows 1st Embodiment which controls the temperature of the substrate processing apparatus of this invention. It is explanatory drawing of the temperature difference table at the time of stability in 1st Embodiment. It is a flowchart in a 1st embodiment. It is a block diagram of the cascade control loop which shows 2nd Embodiment. It is explanatory drawing of the temperature difference table at the time of stability in 2nd Embodiment. It is a flowchart in 2nd Embodiment. It is a figure which shows the structural example of the vertical type CVD furnace in embodiment. It is a block diagram of the basic cascade control loop in an embodiment. It is a figure which shows the structural example of the apparatus operation part in embodiment. It is a flowchart which shows an example of the process processing performed with the vertical CVD furnace in embodiment. It is a figure which shows an example of the furnace temperature of the process process performed with the vertical type CVD furnace in embodiment.

Explanation of symbols

101 Heater (heating means)
102 External thermocouple (first temperature sensor)
105 Internal thermocouple (second temperature sensor)
107 Temperature controller (control unit)
402 1st PID adjustment part 403 which performs 1st calculation based on correction result 2nd adder 404 which outputs 2nd deviation 2nd PID adjustment part 405 which performs 2nd calculation based on 2nd deviation Third adder 406 for outputting the correction result Stable temperature difference table 406
Y set temperature

Claims (2)

A processing chamber for processing a substrate divided into a plurality of zones ;
Heating means are divided into each of the plurality of zones to heat the inside of the processing chamber,
A first temperature sensor disposed outside the processing chamber and measuring the temperature of the heating means for each of the plurality of zones ;
A second temperature sensor that is disposed near the substrate than the first temperature sensor and measures the temperature in the processing chamber for each of the plurality of zones ;
Control means for controlling the heating means for each of the plurality of zones so as to process the substrate at a set temperature in the processing chamber based on the temperatures measured by the first and second temperature sensors,
The control means includes
The temperature difference between the temperatures measured by the first and second temperature sensors when the temperature is stabilized at the set temperature, obtained before the second temperature sensor cannot normally measure the temperature, is stored. It has a stable temperature difference table,
While controlling the heating means , the temperature measured by the second temperature sensor with respect to the zone corresponding to the second temperature sensor that has become unable to measure the temperature normally among the plurality of zones, Instead of performing the first calculation based on the deviation from the set temperature, the set temperature is corrected by the temperature difference stored in the stable temperature difference table, and the correction result and the first temperature sensor are measured. A substrate processing apparatus, wherein a second calculation is performed based on a deviation from a temperature to be controlled, and the heating unit is controlled for each of the plurality of zones based on the second calculation result. The temperature of the heating means is measured for each of the plurality of zones so that the processing chamber divided into the plurality of zones is heated by the heating means divided for each of the plurality of zones and the substrate is processed at a set temperature. a temperature measuring of the first temperature sensor, a temperature measuring of the second temperature sensor than the temperature sensor of the first is disposed on the substrate near to measure the temperature of the processing chamber to each of the plurality of zones, the When controlling the heating means for each of the plurality of zones based on,
When any one of the second temperature sensors cannot measure the temperature normally, the temperature measured by the second temperature sensor for the zone corresponding to the second temperature sensor that cannot measure the temperature normally. Instead of performing the first calculation based on the deviation between the temperature and the set temperature, the second temperature sensor was obtained in advance and stored in the stable temperature difference table before the temperature could not be measured normally . The set temperature is corrected by the temperature difference between the temperatures measured by the first and second temperature sensors when the temperature is stabilized at the set temperature, and the correction result and the first temperature sensor are measured. A method of manufacturing a semiconductor device, wherein a second calculation is performed based on a deviation from a temperature, and the heating means is controlled for each of the plurality of zones based on the second calculation result.

Images