Temperature control method and substrate processing device

Abstract

To perform temperature control with more precise accuracy than a control limit value of a heating section in a substrate processing device.SOLUTION: A temperature control method is executed in a substrate processing device comprising a processing container, where a substrate is carried in and carried out, and a heating section which heats the inside of the processing container. The temperature control method includes the steps of: (a) setting a temperature change amount with respect to a target temperature having a value to a second digit smaller than a first digit indicating a control limit value of the heating section; (b) calculating a ratio in which the temperature change amount is divided into a first temperature equal to or higher than the first digit and a second temperature lower than the first digit and a time decomposed into a digit differential between the first digit and the second digit is divided into a first time corresponding to the second temperature and the other second time; and (c) controlling the heating section in such a manner that a temperature is made rise and fall at times before and after the times of processing steps of the substrate are divided in the ratio.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a temperature control method and a substrate processing apparatus. [Background technology]

[0002] For example, Patent Document 1 proposes a film formation method in which either the heater temperature setting or the number of ALD cycles is adjusted by recipe optimization calculation. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-174983 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique for controlling the temperature of a heating unit in a substrate processing apparatus with greater precision than the control limit value of the heating unit. [Means for solving the problem]

[0005] According to one aspect of the present disclosure, there is provided a temperature control method performed in a substrate processing apparatus including a processing vessel into which a substrate is loaded and unloaded, and a heating unit that heats the inside of the processing vessel, the temperature control method comprising: (a) setting a temperature change amount relative to a target temperature having a value up to two digits smaller than the first digit indicating the control limit value of the heating unit; (b) dividing the temperature change amount into a first temperature equal to or greater than the first digit and a second temperature equal to or less than the first digit, and calculating a ratio for dividing a time decomposed into the digits of the difference between the first digit and the second digit into a first time corresponding to the second temperature and a second time other than the first time; and (c) controlling the heating unit to raise and lower the temperature before and after dividing the time of the substrate processing step into the ratio. Effect of the Invention

[0006] According to one aspect, it is possible to perform temperature control with precision finer than the control limit value of a heating unit in a substrate processing apparatus. [Brief description of the drawings]

[0007] [Figure 1] 1 is a schematic cross-sectional view showing an example of a substrate processing apparatus according to an embodiment; [Diagram 2] FIG. 2 is a diagram for explaining the film thickness distribution and the control limit (temperature control resolution) of a heater. [Diagram 3] FIG. 13 is a diagram illustrating an example of temperature control performed with precision finer than the control limit according to an embodiment. [Figure 4] FIG. 2 is a conceptual diagram of a temperature control method according to an embodiment. [Diagram 5] FIG. 4 is an explanatory diagram of a temperature control method according to an embodiment. [Figure 6] 4 is a flowchart illustrating an example of a temperature control method according to an embodiment. [Figure 7] FIG. 13 is a diagram showing an example of predicted values ​​and actual measured values ​​for a target film thickness according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and duplicated descriptions may be omitted.

[0009] [Substrate processing equipment] With reference to FIG. 1, a configuration of a substrate processing apparatus 1 according to an embodiment capable of performing a substrate processing method described later will be described. FIG. 1 is a schematic cross-sectional view showing an example of the substrate processing apparatus 1 according to an embodiment. The substrate processing apparatus 1 according to this embodiment has a substantially cylindrical processing vessel 4 whose longitudinal direction is vertical. The processing vessel 4 has a double-tube structure including a cylindrical inner tube 6 and an outer tube 8 having a ceiling concentrically arranged outside the inner tube 6. However, the substrate processing apparatus 1 may have a single-tube structure having a single cylinder. The inner tube 6 and the outer tube 8 are formed of a heat-resistant material such as quartz. Inside the processing vessel 4, substrate processing such as film formation processing is performed on a plurality of substrates W.

[0010] The inner cylinder 6 and the outer cylinder 8 are held at their lower ends by a manifold 10 made of stainless steel or the like. The manifold 10 is fixed to, for example, a base plate (not shown). The manifold 10, together with the inner cylinder 6 and the outer cylinder 8, forms a substantially cylindrical internal space, and is therefore considered to form a part of the processing vessel 4.

[0011] That is, the processing vessel 4 comprises an inner tube 6 and an outer tube 8 formed of a heat-resistant material such as quartz, and a manifold 10 formed of stainless steel or the like, and the manifold 10 is provided on the lower part of the side of the processing vessel 4 so as to support the inner tube 6 and the outer tube 8 from below.

[0012] The manifold 10 has a gas introduction part 20 that introduces a processing gas used for substrate processing into the processing vessel 4. Although Fig. 1 shows a configuration in which one gas introduction part 20 is provided, the present invention is not limited thereto, and multiple gas introduction parts 20 may be provided depending on the type of gas used, etc.

[0013] An inlet pipe 22 for introducing a processing gas into the processing vessel 4 is connected to the gas inlet part 20. The inlet pipe 22 is provided with a flow rate regulator 24 such as a mass flow controller for adjusting the gas flow rate, a valve (not shown), and the like.

[0014] The manifold 10 also has a gas exhaust unit 30 that exhausts the inside of the processing vessel 4. The gas exhaust unit 30 is connected to an exhaust pipe 36 including a vacuum pump 32 capable of controlling the pressure reduction inside the processing vessel 4, an aperture variable valve 34, and the like.

[0015] A furnace port 40 is formed at the lower end of the manifold 10, and a disk-shaped lid 42 made of, for example, stainless steel is provided on the furnace port 40. The lid 42 is provided so as to be movable up and down by a lifting mechanism 44 that functions as a boat elevator, for example, and is configured to be able to hermetically seal the furnace port 40.

[0016] An insulation cylinder 46 made of, for example, quartz is placed on the lid 42. A wafer boat 48 made of, for example, quartz is placed on the insulation cylinder 46, and holds, for example, about 50 to 200 substrates W in a horizontal state in multiple stages at predetermined intervals. The substrates W placed on the wafer boat 48 constitute one batch, and various substrate processes are performed on a batch basis. An example of the substrate W is a wafer having a diameter of 200 mm to 300 mm. The wafer boat 48 is an example of a boat that holds multiple substrates in multiple slots arranged in multiple stages in the vertical direction and is carried in and out of the processing vessel 4.

[0017] The wafer boat 48 is loaded (carried into) the processing vessel 4 by raising the lid body 42 using the lifting mechanism 44, and substrate processing is performed on the substrates W held in the wafer boat 48. After the substrate processing is performed, the lid body 42 is lowered using the lifting mechanism 44, and the wafer boat 48 is unloaded (carried out) from the processing vessel 4 to a loading area below.

[0018] A heater 60 having, for example, a cylindrical shape, capable of controlling heating of the processing vessel 4 to a predetermined temperature is provided on the outer periphery of the processing vessel 4. The heater 60 is an example of a heating unit that heats the inside of the processing vessel 4. The heater 60 has multiple heaters 60a to 60f that adjust the temperatures of multiple substrates W accommodated inside the processing vessel 4 for each of multiple zones.

[0019] The heaters 60a to 60f are provided vertically from the top to the bottom. The heaters 60a to 60f are configured so that the heater output values ​​(power, heat generation amount) can be controlled independently by the power controllers 62a to 62f, respectively. Furthermore, temperature sensors 65a to 65f are provided inside the inner cylinder 6 corresponding to the heaters 60a to 60f. The temperature sensors 65a to 65f are provided vertically from the top to the bottom. For example, thermocouples and resistance temperature detectors can be used as the temperature sensors 65a to 65f. The temperature sensors 65a to 65f are also collectively referred to as temperature sensors 65.

[0020] The heaters 60a-60f are provided for each zone corresponding to the multiple zones into which the area of ​​the wafer boat 48 in which the substrates are accommodated is divided. In the substrate processing apparatus 1, the wafer boat 48 is divided into six zones, as an example. The six zones are called "TOP", "CTR4", "CTR3", "CTR2", "CTR1", and "BTM" from the top.

[0021] Heater 60a heats multiple substrates in the "TOP" zone. Temperature sensor 65a measures the temperature of the "TOP" zone in inner cylinder 6. Hereinafter, the temperature of each zone in inner cylinder 6 is also simply referred to as the temperature of the zone. Heater 60b heats multiple substrates in the "CTR4" zone. Temperature sensor 65b measures the temperature of the "CTR4" zone. Heater 60c heats multiple substrates in the "CTR3" zone. Temperature sensor 65c measures the temperature of the "CTR3" zone. Heater 60d heats multiple substrates in the "CTR2" zone. Temperature sensor 65d measures the temperature of the "CTR2" zone. Heater 60e heats multiple substrates in the "CTR1" zone. Temperature sensor 65e measures the temperature of the "CTR1" zone. Heater 60f heats multiple substrates in the "BTM" zone. Temperature sensor 65f measures the temperature of the "BTM" zone.

[0022] The control device 100 controls the overall operation of the substrate processing apparatus 1. The control device 100 includes a CPU 101 and a memory 102. The CPU 101 is a computer for controlling the overall operation of the substrate processing apparatus 1.

[0023] The memory 102 stores a control program for implementing the substrate processing performed by the substrate processing apparatus 1 under the control of the control device 100, and a recipe in which a substrate processing procedure and the like are set for each step. The memory 102 also stores various programs for causing each unit of the substrate processing apparatus 1 to execute the substrate processing according to the process conditions set in the recipe. The various programs can be stored in a storage medium and then stored in the memory 102. The storage medium may be a hard disk or a semiconductor memory, or may be a portable medium such as a CD-ROM, a DVD, or a flash memory. These programs, parameters, and various data may be appropriately transmitted to the memory 102 from another apparatus or a host computer by a communication means such as a wired or wireless communication means. The control device 100 may be a control device provided separately from the substrate processing apparatus 1. The memory 102 may be a storage device provided separately from the substrate processing apparatus 1.

[0024] Detection signals from the temperature sensors 65a-65f are transmitted to the control device 100. The control device 100 calculates setting values ​​for the power controllers 62a-62f based on the detection signals from the temperature sensors 65a-65f, and outputs the calculated setting values ​​to each of the power controllers 62a-62f. In this way, the output value (Power) of each of the heaters 60a-60f is controlled independently.

[0025] [Temperature control] In the substrate processing apparatus 1, the inter-surface uniformity of the film thickness of the substrate W from the "TOP" to "BTM" zones is adjusted by changing the temperature for each zone. The optimal temperature combination for each zone to improve the inter-surface uniformity may be calculated using optimization software (optimization model).

[0026] The inter-surface uniformity of the film thickness is adjusted within the range of the resolution of the temperature control. Therefore, the inter-surface uniformity of the film thickness can only be improved within the range that can be adjusted at the control limit (temperature control resolution) of the heater 60. Conventionally, the inter-surface uniformity of the film thickness has been adjusted in units of 0.1°C, which is the temperature control resolution of the substrate processing apparatus 1. In this case, the range that can be adjusted in units of 0.1°C is the limit to which the inter-surface uniformity of the film thickness can be improved.

[0027] In recent years, semiconductors have become increasingly miniaturized, and customer demands for further miniaturization are high. Depending on the level of uniformity required, it is anticipated that there may be cases where the limits of the temperature control resolution described above will not be able to meet customer demands for further miniaturization.

[0028] For example, referring to FIG. 2, which explains the film thickness distribution and the control limit (temperature control resolution) of the heater 60, FIG. 2(a) shows an example of the film thickness of the film formed when all zones are controlled to the same target temperature and film formation is performed. Even though all zones are controlled to the same temperature, the film thickness of each zone is not the same as the target value, and there is a deviation between the zones. Therefore, in FIG. 2(b) and (c), the target temperature for each zone is changed separately, and the heaters 60a to 60f are controlled so that each zone has its own target temperature, thereby making the film thickness for each zone match or approach the target value. In this way, since the deviation from the target value of the film thickness is controlled by temperature adjustment, the range in which the film thickness changes with the controllable temperature control resolution is the limit of adjustment. FIG. 2(b) shows the film formed result when the temperature adjustment is performed in units of 0.1°C, which is the minimum digit of the control limit of the heaters 60a to 60f. FIG. 2(c) shows the film formed result when the temperature adjustment is performed in units of 0.01°C. In the temperature adjustment during film formation in Fig. 2(c), the temperature can be controlled with higher resolution than in the temperature adjustment during film formation in Fig. 2(b). Therefore, the film formation result shown in Fig. 2(c) allows for more precise film thickness adjustment than the film formation result shown in Fig. 2(b), and the film thickness of each zone matches or approaches the target value more closely.

[0029] For example, since the temperature control in Fig. 2(b) is in units of 0.1°C, if the heater 60 is controlled by subtracting 0.17°C from the current temperature value of "CTR2", even if the film thickness matches the target value, the film thickness cannot match the target value and deviates slightly from the target value because the current temperature value is adjusted by subtracting -0.2°C. On the other hand, since the temperature control in Fig. 2(c) is in units of 0.01°C, the heater 60 can be controlled by subtracting 0.17°C from the current temperature value of "CTR2", and the film thickness can match the target value.

[0030] Therefore, the temperature of each zone in the processing (film formation) step performed in the substrate processing apparatus 1 is changed in a pulsed manner, and the time before and after the change is divided by a ratio, so that the temperature control resolution is made finer than the control limit value (minimum value of the control limit) of the heating unit, and temperature control is performed with higher resolution. This makes it possible to improve the inter-surface uniformity of the film thickness without changing the hardware configuration of the substrate processing apparatus 1.

[0031] FIG. 3 is a diagram showing an example of temperature control performed with a finer accuracy than the control limit of the heater 60 according to an embodiment. For example, when it is desired to control a 30-minute film formation step to a target temperature of 500.07°C, the film formation step is divided into two steps with set temperatures of 500.0°C and 500.1°C. The time ratio of each step is set in the recipe so that the ratio is 3:7=9 minutes:21 minutes. Then, according to the recipe, the heater 60 is controlled to 500.0°C for 9 minutes of step I of the 30-minute film formation step, and the heater 60 is controlled to 500.1°C for 21 minutes of step II. This allows the heater 60 to be controlled to the target temperature of the substrate of 500.07°C in the film formation step.

[0032] This allows temperature control with a control resolution of 0.01°C or less (such as 0.001°C) while maintaining the temperature control mechanism with a control limit value of 0.1°C increments for the heater 60, without changing the hardware configuration of the substrate processing apparatus 1.

[0033] FIG. 4 is a conceptual diagram of a temperature control method according to an embodiment. In the temperature control method according to the conventional example in FIG. 4(b), the optimum temperature change amount from the "TOP" to the "BTM" zones is calculated using optimization software for the target temperature before optimization in FIG. 4(a), and is added to the target temperature of each zone for optimization. In the temperature control method according to the present embodiment in FIG. 4(c), the temperature is optimized for each zone in the same manner as in the conventional example for the target temperature before optimization in FIG. 4(a). At the same time, the temperature change timing (e.g., 9 minutes and 21 minutes) of the temperatures (500.0°C, 500.1°C) shown in FIG. 3 is calculated as an example.

[0034] Specifically, first calculate the target temperature with any number of digits. In Fig. 4(a), the target temperature is calculated as 850°C for all zones. In Fig. 4(a), the film formation step is used as an example, but similar temperature control is possible for other substrate processing steps.

[0035] The calculation of the optimal temperature change amount for the target temperature in Fig. 4(b-1) and (c-1) is optimized using quadratic programming. The number of digits of the temperature calculated here can be determined by the user. In the conventional example, the calculated optimal temperature is rounded to the first decimal place of the control limit value of the heater 60 and notified to the user. In this embodiment, it is rounded to the number of digits set by the user. Quadratic programming is a method for calculating optimal conditions. The quadratic programming according to this embodiment is a method for calculating a combination of optimal temperature change amounts for each zone that reduces the gap with the target temperature before optimization using an optimization model (optimization software). The optimization model specifies how many degrees the substrate temperature will change if the temperature of the "TOP" is increased by 1°C, how much the film thickness will change if the temperature of the substrate is increased by 1°C, etc.

[0036] In the conventional example, as shown in Fig. 4(b-1), the temperature change amount of each zone from "TOP" to "BTM" is calculated, and as shown in Fig. 4(b-2), the heater 60 of each zone is independently controlled so that the temperature change amount is added to the target temperature before optimization. As a result, "TOP" is controlled to 852°C based on the temperature change amount of +2°C, "T / C" is controlled to 850°C based on the temperature change amount of 0°C, "C / B" is controlled to 848°C based on the temperature change amount of -2°C, and "BTM" is controlled to 846°C based on the temperature change amount of -4°C. Note that "T / C" is a general term for the "CTR4" and "CTR3" zones, and "C / B" is a general term for the "CTR2" and "CTR1" zones.

[0037] In this embodiment, as shown in FIG. 4(c-1), the temperature change amount of each zone from "TOP" to "BTM" is calculated in units determined by the user (here, in units of 0.01°C (two decimal places)). The temperature change amount shown in FIG. 4(c-1) is divided into a numerical value up to the first decimal place shown in FIG. 4(c-1-1) and a numerical value to the second decimal place shown in FIG. 4(c-1-2). The numerical value to the first decimal place is the control limit value of the heater 60, and the digit of the control limit value is the lowest digit of the control limit of the heater 60. The numerical value shown in FIG. 4(c-1-2) is the numerical value to the second decimal place, and the numerical value to the second decimal place is the numerical value exceeding the control limit of the heater 60.

[0038] The heaters 60 in each zone are independently controlled so that the values ​​shown to the first decimal place in Fig. 4(c-1-1) are the pre-optimization target temperature plus the temperature change amount, as shown in Fig. 4(c-2-1), as in the conventional example. As a result, "TOP" is controlled to 852°C based on a temperature change amount of +2°C, "T / C" is controlled to 850°C based on a temperature change amount of 0°C, "C / B" is controlled to 848°C based on a temperature change amount of -2°C, and "BTM" is controlled to 846°C based on a temperature change amount of -4°C.

[0039] At the same time as this control, a pulse output is performed in accordance with the temperature change timing (see FIG. 4(c-2-2)). For example, the "TOP" is divided into two set temperature steps, 852.00°C and 852.01°C. The time ratio of each step is set in the recipe so that the ratio is 2:8. Then, according to the recipe, the heater 60 is controlled to 852.00°C during the first hour of step I of the film formation step, and the heater 60 is controlled to 852.01°C during the second hour of step II. This makes it possible to control the heater 60 to the target temperature of 852.02°C during the film formation step. This causes the "TOP" to be controlled to 852°C + 0.02°C. The other zones are controlled in the same way. This allows temperature control in each zone with a precision finer than the control limit value of the heater 60 (here, the first decimal place).

[0040] The control limit value of the heater 60, which is a value up to one decimal place, is notified to the user as the temperature to be set in the substrate processing apparatus 1. The temperature change timing is calculated using the temperature control method described with reference to FIG. 3 for a value exceeding the control limit value of the heater 60, and notified to the user. The user sets the optimized temperature based on the notified amount of temperature change and the pulsed temperature change timing in the recipe. Alternatively, the optimized temperature based on the notified amount of temperature change and the pulsed temperature change timing may be automatically set in the recipe. The control apparatus 100 executes the film formation step according to the recipe.

[0041] In manual or automatic setting of the recipe, the film formation step is divided into (number of zones + 1) steps, so that the temperature change amount can be controlled at a separate timing for each zone. FIG. 5 is an explanatory diagram of a temperature control method according to an embodiment. For example, in the example of FIG. 5, the timing of changing the temperature differs for each zone, so the film formation step is divided into seven steps, which is the number of six zones from "TOP" to "BTM" plus one, so that the temperature can be changed for each zone. Although each time period A to G is shown equally in FIG. 5, it may be changed depending on the timing of temperature change by pulses for each zone.

[0042] [Temperature control method] A temperature control method according to an embodiment will be described with reference to Fig. 6. Fig. 6 is a flowchart showing an example of the temperature control method according to an embodiment. The temperature control method according to the present embodiment is controlled by the control device 100 and executed by the substrate processing apparatus 1.

[0043] In step S1, the control device 100 acquires a target temperature. In the example of Fig. 4(a), 850°C is acquired as the target temperature for each step of the film formation step. In addition, the control device 100 acquires a second digit that is smaller than the first digit, which is the lowest digit of the temperature control limit. The second digit is determined in advance by the user.

[0044] Next, in step S2, the control device 100 calculates the amount of temperature change for each zone using an optimization model (optimization software). In the example of Fig. 4(c-1), the amount of temperature change is calculated for each zone.

[0045] Next, in step S3, the control device 100 divides the target temperature for each zone into a first temperature having a digit or more indicating the lowest digit of the control limit of the heater 60, and a second temperature having a digit or more smaller than the first digit. In the example of Fig. 4(c-1), the numerical value up to the first decimal place shown in Fig. 4(c-1-1) is the first temperature. The numerical value in the second digit (second decimal place) smaller than the first digit shown in Fig. 4(c-1-2) is the second temperature.

[0046] Next, in step S4, the control device 100 calculates a ratio for dividing the time resolved into the difference between the first and second digits into a first time corresponding to the second temperature and a second time other than the first time.

[0047] For example, in the example of Fig. 4(c-1), the first digit is the first decimal place, and the second digit is the second decimal place. For the second temperature "+0.02°C" which is the temperature change amount of the "TOP" zone shown in Fig. 4(c-1-2), the time decomposed into 1 / 10, which is the difference between the first and second digits, is made into a two-level pulse corresponding to the second temperature +0.02°C. In other words, the film formation time is divided into the first time (2 / 10) corresponding to the second temperature "+0.02°C" and the second time (8 / 10) other than that in a ratio of 1:4, and the temperature is controlled in a pulsed manner.

[0048] Next, in step S5, the control device 100 controls the first temperature to a temperature that is changed according to the temperature change amount for each zone. In Fig. 4 (c-2-1), the first temperature (850°C) is controlled to temperatures of 852°C, 850°C, 848°C, and 846°C that are changed according to the temperature change amount for each zone from "TOP" to "BTM".

[0049] Furthermore, the control device 100 controls the first time to a value obtained by adding 1 to the least significant digit of the first temperature, and controls the second time to the first temperature. In FIG. 4(c-2-2), the first time is controlled to a value (850.1°C) obtained by adding 1 to the least significant digit (first decimal place) of the first temperature (850°C), and the second time is controlled to the first temperature (850.0°C). The ratio of the first time to the second time is 1:4. The control device 100 may control the first temperature to a value (852.1°C) obtained by adding 1 to the least significant digit (first decimal place) of the temperature after changing the temperature change amount for each zone (for example, 852°C for "TOP"), and control the second time to the temperature after changing (852.0°C).

[0050] As a result, in the case of the "TOP" zone, in order to control the temperature to 850.02°C by adding the temperature change amount to the target temperature of 850°C, 850.1°C (or 852.1°C) is controlled at a ratio of 2 / 10 and 850.0°C (or 852.0°C) at a ratio of 8 / 10. This makes it possible to control the temperature of the "TOP" zone to the temperature-optimized 852.02°C. As a result, it is possible to control the temperature to a place below the control limit value (the first decimal place in the example of Figure 4) (the second decimal place in the example of Figure 4).

[0051] Next, in step S6, the control device 100 loads a substrate into the processing chamber, prepares the substrate, and performs a film forming process. The substrate may be prepared before step S6.

[0052] Next, in step S7, the control device 100 judges whether the film formation result is a desired result. If the control device 100 judges that the film formation result is a desired result, the control device 100 ends this process. If the control device 100 judges that the film formation result is not a desired result, the control device 100 returns to step S1 and performs the process from step S1 onwards again.

[0053] [effect] An example of predicted values ​​(simulation result values) and actual measured values ​​(experiment result values) for a target film thickness according to an embodiment will be described with reference to Fig. 7. Fig. 7 is a diagram showing an example of predicted values ​​and actual measured values ​​for a target film thickness according to an embodiment.

[0054] FIG. 7(a) shows the temperature change amount of each zone from "TOP" to "BTM" relative to the target temperature before optimization adjustment by the temperature control method according to this embodiment, normalized with "TOP" as "0.00". While the control limit value is in units of 0.1°C, the temperature change amount is in units of 0.01°C because the temperature control method according to this embodiment is used. Note that the temperature change amount can also be controlled in units finer than 0.01°C. For example, when controlling to 500.012°C in units of 0.001°C, the film formation step is performed at a ratio of 88 / 100 for 500.0°C and 12 / 100 for 500.1°C.

[0055] When the temperature change amount was controlled in increments of 0.01°C, the inter-surface uniformity of the film thickness predicted by simulation (predicted film thickness) was 0.43%, which was a better result than the inter-surface uniformity of the actual film thickness measured before optimization adjustment (actual film thickness), which was 0.50%.

[0056] When the temperature change amount was controlled in increments of 0.01°C, the inter-surface uniformity of the actual film thickness (actual film thickness) when film formation was performed using the substrate processing apparatus 1 was 0.45%, which was a better result than the inter-surface uniformity of the actual film thickness (actual film thickness) of 0.50% measured before optimization adjustment.

[0057] The horizontal axis in FIG. 7(b) is the slot number of the wafer boat 48. The slot numbers are numbered in ascending order starting from the top "TOP". The vertical axis in FIG. 7(b) indicates the relative film thickness to the target film thickness. The target film thickness is indicated by a solid line and is normalized as 1.

[0058] The inter-surface uniformity of the predicted and measured film thicknesses when optimized in increments of 0.01°C was improved compared to the inter-surface uniformity of the measured film thickness before optimization. Also, the inter-surface uniformity of the predicted and measured film thicknesses when optimized in increments of 0.01°C was better than the inter-surface uniformity of the predicted film thickness when optimized in increments of 0.1°C.

[0059] As described above, according to the temperature control method and substrate processing apparatus of this embodiment, the temperature can be controlled with a precision finer than the control limit value of the heating unit in the substrate processing apparatus. Therefore, by controlling the temperature with a finer temperature resolution, it is possible to improve the inter-surface uniformity of the film thickness more than with normal temperature adjustment. This improves the inter-surface uniformity of the film thickness, thereby improving the yield. As a result, the improved yield is expected to reduce financial and time costs. It can also contribute to further miniaturization of semiconductors.

[0060] Furthermore, according to the temperature control method of this embodiment, it is possible to adjust the inter-surface uniformity of the film thickness with higher accuracy without modifying the hardware configuration of the substrate processing apparatus 1 (within the range of normal operation). Furthermore, the optimization software (optimization model) can calculate the temperature change amount in units of 0.1°C as well as the temperature change timing suitable for any control digit. Temperature control more precise than one decimal place is possible by dividing the time into smaller units (for example, 1:99, etc.).

[0061] In the above embodiment, temperature control has been described, but by performing gas flow rate control and pressure control similar to the temperature control described above, gas flow rate control and pressure control can be performed with precision finer than the control limits of the substrate processing apparatus 1.

[0062] The temperature control method and the substrate processing apparatus according to the presently disclosed embodiments should be considered as illustrative and not restrictive in all respects. The embodiments can be modified and improved in various ways without departing from the scope and spirit of the appended claims. The matters described in the above embodiments can be configured in other ways without contradiction, and can be combined without contradiction.

[0063] In the above embodiment, the substrate processing apparatus according to the present embodiment is a batch-type film forming apparatus that processes a plurality of substrates at once, but the present disclosure is not limited thereto. The substrate processing apparatus according to the present embodiment may be a single-wafer film forming apparatus that processes wafers one by one. The substrate processing apparatus may be a semi-batch-type film forming apparatus that revolves a plurality of wafers arranged on a turntable in a processing vessel by the turntable, and processes the wafers by passing them in order through an area where a first gas is supplied and an area where a second gas is supplied. The substrate processing apparatus may be a multiple-wafer film forming apparatus equipped with a plurality of mounting tables in one processing vessel. [Explanation of symbols]

[0064] 1. Substrate Processing Equipment 4 Processing vessel 48 Wafer Boat 60a~60f heater 65a~65f Temperature Sensor 100 Control device

Claims

1. a processing vessel into which substrates are loaded and unloaded; a heating unit that heats the inside of the processing vessel; A temperature control method performed in a substrate processing apparatus comprising: (a) setting a temperature change amount for a target temperature having a value up to two digits smaller than a first digit indicating a control limit value of the heating unit; (b) dividing the amount of change in temperature into a first temperature equal to or greater than the first digit and a second temperature less than the first digit, and calculating a ratio of a time decomposed into the difference between the first digit and the second digit into a first time corresponding to the second temperature and a second time other than the first time; (c) controlling the heating unit so as to increase or decrease the temperature before and after dividing the time of the substrate processing step by the ratio; The temperature control method comprises:

2. The step (c) comprises: Of the times before and after the ratio, the first time is controlled to a value obtained by adding 1 to the first digit of the first temperature, and the second time is controlled to the first temperature. The temperature control method according to claim 1 .

3. The substrate processing apparatus includes: a boat for holding a plurality of the substrates in a plurality of slots arranged in multiple stages in a vertical direction and for carrying the substrates into and out of the processing vessel; The steps (a) to (c) are When the plurality of slots are divided into a plurality of zones, the temperature change amount is set for each zone with respect to the target temperature, and the heating unit for each zone is independently controlled so as to raise and lower the temperature before and after the time period before and after the division for each zone by the ratio. The temperature control method according to claim 1 .

4. The step (c) comprises: While controlling the heating unit to a value obtained by adding the first temperature to the target temperature in the processing step, the heating unit is controlled so as to increase and decrease the temperature before and after dividing the time of the processing step into the ratio. The temperature control method according to any one of claims 1 to 3.

5. (d) preparing a substrate in the processing vessel and processing the substrate in the processing step; The temperature control method according to any one of claims 1 to 3.

6. a processing vessel into which substrates are loaded and unloaded; a heating unit that heats the inside of the processing vessel; A control unit; A substrate processing apparatus comprising: The control unit is (a) setting a temperature change amount for a target temperature having a value up to two digits smaller than a first digit indicating a control limit value of the heating unit; (b) dividing the amount of change in temperature into a first temperature equal to or greater than the first digit and a second temperature less than the first digit, and calculating a ratio of a time decomposed into the difference between the first digit and the second digit into a first time corresponding to the second temperature and a second time other than the first time; (c) controlling the heating unit so as to increase or decrease the temperature before and after dividing the time of the substrate processing step by the ratio; The substrate processing apparatus controls a process including the steps of:

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