Temperature control method and substrate processing apparatus

Abstract

The invention provides a temperature control method and a substrate processing apparatus. Temperature control is carried out with precision which is finer than a control limit value of a heating part. The temperature control method is executed by a substrate processing apparatus including a processing container and a heating unit capable of heating the inside of the processing container, the substrate processing apparatus including: a step of setting a temperature change amount with respect to a target temperature; the value of the target temperature has a value up to a second bit smaller than a first bit representing a control limit value of the heating unit; a step b of dividing the amount of change in temperature into a first temperature greater than or equal to a first bit and a second temperature less than the first bit, and calculating the ratio of dividing a time length into a first time corresponding to the second temperature and a second time other than the first time, the time length being divided into multiple parts corresponding to the difference between the order of magnitude of the first bit and the order of magnitude of the second bit; and c, controlling the heating part so that the temperature changes up and down in the time before and after the time of the processing step of the substrate is divided by the ratio.

Description

Technical Field

[0001] The invention relates to a temperature control method and a substrate processing device. Background Art

[0002] For example, Patent Document 1 proposes a film forming method in which either the set temperature of a heater or the number of ALD cycles is adjusted by process recipe optimization calculation.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-174983 Summary of the invention

[0006] Technical problem to be solved by the invention

[0007] The present invention provides a technology capable of performing temperature control with a higher accuracy than a control limit value of a heating portion in a substrate processing apparatus.

[0008] Technical solutions for solving technical problems

[0009] According to one embodiment of the present invention, there is provided a temperature control method, which is performed by a substrate processing device including a processing container and a heating unit, wherein the processing container is configured to be able to carry a substrate into and out of the processing container, and the heating unit is capable of heating the inside of the processing container, the temperature control method comprising: a step of setting a temperature change amount for a target temperature, wherein the value of the target temperature has a numerical value up to a second digit that is smaller than a first digit representing a control limit value of the heating unit; b step of dividing the temperature change amount into a first temperature above the first digit and a second temperature less than the first digit, and calculating a ratio of a time length into a first time corresponding to the second temperature and a second time outside the first digit, wherein the time length is split into multiples corresponding to a difference in order of magnitude between the first digit and the second digit; and c step of controlling the heating unit so that the temperature varies up and down before and after the time of the processing step of the substrate is divided according to the ratio.

[0010] Effects of the Invention

[0011] According to one aspect, it is possible to perform temperature control with a higher accuracy than a control limit value of a heating portion in a substrate processing apparatus. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic cross-sectional view showing an example of a substrate processing apparatus according to an embodiment.

[0013] Figure 2It is a diagram illustrating the film thickness distribution and the control limit (temperature control resolution) of the heater.

[0014] Figure 3 This is a diagram showing an example of temperature control performed with a higher accuracy than the control limit of one embodiment.

[0015] Figure 4 This is a conceptual diagram of a temperature control method according to an embodiment.

[0016] Figure 5 This is an explanatory diagram of a temperature control method according to an embodiment.

[0017] Figure 6 This is a flowchart showing an example of a temperature control method according to one embodiment.

[0018] Figure 7 This is a diagram showing an example of predicted values ​​and measured values ​​with respect to a target film thickness in one embodiment.

[0019] Description of Reference Numerals

[0020] 1. Substrate processing device

[0021] 4. Processing Container

[0022] 48 Crystal Boat

[0023] 60a~60f heater

[0024] 65a~65f temperature sensor

[0025] 100 control devices. DETAILED DESCRIPTION

[0026] Hereinafter, the mode for implementing the present invention will be described with reference to the drawings. In each of the drawings, the same components are denoted by the same reference numerals, and duplicate descriptions may be omitted.

[0027] [Substrate processing device]

[0028] Reference Figure 1 , a structure of a substrate processing apparatus 1 which is an embodiment of a substrate processing method to be described later will be described. Figure 11 is a schematic cross-sectional view of an example of a substrate processing device 1 according to an embodiment. The substrate processing device 1 according to the present embodiment has a substantially cylindrical processing container 4 whose length direction is a vertical direction. The processing container 4 has a double tube structure, which includes an inner tube 6 of a cylindrical body and an outer tube 8 having a top arranged concentrically outside the inner tube 6. However, the substrate processing device 1 may also be a single tube structure having a cylindrical body. The inner tube 6 and the outer tube 8 are formed of, for example, a heat-resistant material such as quartz. Inside the processing container 4, a plurality of substrates W are subjected to substrate processing such as film forming processing.

[0029] The lower ends of the inner tube 6 and the outer tube 8 are held by a manifold 10 formed of stainless steel or the like. The manifold 10 is fixed to a bottom plate (not shown), for example. The manifold 10 forms a substantially cylindrical internal space together with the inner tube 6 and the outer tube 8, thus forming a part of the processing container 4.

[0030] That is, the processing container 4 includes, for example: 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, etc., which is arranged at the lower side of the processing container 4 in a manner to hold the inner tube 6 and the outer tube 8 from below.

[0031] The manifold 10 has a gas introduction portion 20 for introducing a processing gas for substrate processing into the processing container 4. Figure 1 In the figure, a mode in which one gas introduction part 20 is provided is shown, but the present invention is not limited thereto, and a plurality of gas introduction parts 20 may be provided depending on the type of gas used and the like.

[0032] The gas introduction unit 20 is connected to an introduction pipe 22 for introducing a process gas into the process container 4. The introduction pipe 22 is provided with a flow rate regulator 24 such as a mass flow controller for regulating a gas flow rate, a valve (not shown), and the like.

[0033] The manifold 10 also includes a gas exhaust unit 30 for exhausting the processing container 4. The gas exhaust unit 30 is connected to an exhaust pipe 36 including a vacuum pump 32 capable of controlling the pressure reduction in the processing container 4, a variable opening valve 34, and the like.

[0034] A furnace opening 40 is formed at the lower end of the manifold 10, and a disc-shaped cover 42 made of, for example, stainless steel is provided at the furnace opening 40. The cover 42 is provided to be able to be raised and lowered by, for example, a lifting mechanism 44 functioning as a wafer boat lift, and can hermetically seal the furnace opening 40.

[0035] A heat-insulating cylinder 46 made of, for example, quartz is provided on the cover 42. A wafer boat 48 made of, for example, quartz is placed on the heat-insulating cylinder 46, and the wafer boat 48 holds, for example, about 50 to 200 substrates W in a horizontal state in multiple layers at predetermined intervals. The multiple substrates W placed on the wafer boat 48 constitute a batch, and various substrate processes are performed in units of one batch. As an example of the substrate W, a wafer with a diameter of 200 mm to 300 mm can be cited. The wafer boat 48 is an example of a wafer storage box, which holds a plurality of substrates in a plurality of grooves arranged in multiple layers in the vertical direction, and is carried in and out of the processing container 4.

[0036] The wafer boat 48 is loaded (sent) into the processing container 4 by raising the cover 42 using the lifting mechanism 44, and substrate processing is performed on the substrate W held in the wafer boat 48. After the substrate processing is performed, the cover 42 is lowered using the lifting mechanism 44, and the wafer boat 48 is unloaded (sent out) from the processing container 4 to the loading area below.

[0037] A heater 60, for example, in a cylindrical shape, which can heat and control the processing container 4 to a predetermined temperature, is provided on the outer peripheral side of the processing container 4. The heater 60 is an example of a heating unit that heats the inside of the processing container 4. The heater 60 includes a plurality of heaters 60a to 60f, and the plurality of heaters 60a to 60f adjust the temperature of the plurality of substrates W accommodated in the processing container 4 in each of a plurality of regions.

[0038] The heaters 60a to 60f are arranged from the upper side to the lower side in the vertical direction. The heaters 60a to 60f are configured to be able to independently control the output values ​​(power, calorific value) of the heaters through the power controllers 62a to 62f, respectively. In addition, temperature sensors 65a to 65f are arranged inside the inner tube 6 corresponding to the heaters 60a to 60f. The temperature sensors 65a to 65f are arranged from the upper side to the lower side in the vertical direction. As the temperature sensors 65a to 65f, for example, thermocouples and temperature measuring resistors can be used. The temperature sensors 65a to 65f are also collectively referred to as temperature sensors 65.

[0039] Heaters 60a to 60f are provided in each area corresponding to each area when the substrate storage area of ​​the wafer boat 48 is divided into a plurality of areas. In the substrate processing apparatus 1, as an example, the wafer boat 48 is divided into six areas. The six areas are sequentially referred to as "TOP", "CTR4", "CTR3", "CTR2", "CTR1", and "BTM" from the top.

[0040] Heater 60a heats multiple substrates in the "TOP" area. Temperature sensor 65a measures the temperature of the "TOP" area in the inner cylinder 6. Hereinafter, the temperature of each area in the inner cylinder 6 is also referred to as the temperature of the area. Heater 60b heats multiple substrates in the "CTR4" area. Temperature sensor 65b measures the temperature of the "CTR4" area. Heater 60c heats multiple substrates in the "CTR3" area. Temperature sensor 65c measures the temperature of the "CTR3" area. Heater 60d heats multiple substrates in the "CTR2" area. Temperature sensor 65d measures the temperature of the "CTR2" area. Heater 60e heats multiple substrates in the "CTR1" area. Temperature sensor 65e measures the temperature of the "CTR1" area. Heater 60f heats multiple substrates in the "BTM" area. Temperature sensor 65f measures the temperature of the "BTM" area.

[0041] 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.

[0042] The memory 102 stores: a control program for realizing the substrate processing performed by the substrate processing device 1 under the control of the control device 100, and a processing scheme in which the substrate processing order is set in each step. In addition, the memory 102 stores various programs for making each part of the substrate processing device 1 perform substrate processing according to the processing conditions set in the processing scheme. Various programs can be stored in a storage medium and can be stored in the memory 102. The storage medium can be a hard disk, a semiconductor memory, or a portable medium such as a CD-ROM, a DVD, a flash memory, etc. In addition, these programs, parameters, and various data can also be appropriately transmitted from other devices or a host computer to the memory 102 through communication methods such as wired or wireless. In addition, the control device 100 can also be a control device set separately from the substrate processing device 1. In addition, the memory 102 can also be a storage device set separately from the substrate processing device 1.

[0043] The detection signals from the temperature sensors 65a to 65f are sent to the control device 100. In the control device 100, the setting values ​​of the power (electric power) controllers 62a to 62f are calculated based on the detection signals from the temperature sensors 65a to 65f, and the calculated setting values ​​are output to each power controller 62a to 62f. Thus, the output values ​​(Power) of the heaters 60a to 60f are controlled independently.

[0044] [Temperature control]

[0045] In the substrate processing apparatus 1, the inter-surface uniformity of the film thickness of the substrate W from the "TOP" to the "BTM" region is adjusted by changing the temperature for each region. The combination of the optimal temperature for each region to improve the inter-surface uniformity is sometimes calculated using optimization software (optimization model).

[0046] The inter-plane uniformity of the film thickness is adjusted within the range of the temperature control resolution. Therefore, the inter-plane uniformity of the film thickness can only be improved within the range that can be adjusted according to the control limit (temperature control resolution) of the heater 60. Conventionally, the inter-plane uniformity of the film thickness is adjusted in units of 0.1°C, which is the temperature control resolution of the substrate processing device 1. In this case, the range that can be adjusted in units of 0.1°C becomes the limit of the improvement of the inter-plane uniformity of the film thickness.

[0047] Recently, semiconductor miniaturization has been progressing, and customers' demands for miniaturization have become increasingly high. Depending on the degree of uniformity required, there may be a situation where the customer's demands for miniaturization cannot be met within the limit of the temperature control resolution described above.

[0048] For example, see the description of the film thickness distribution and the control limit (temperature control resolution) of the heater 60. Figure 2 , Figure 2 (a) shows an example of the film thickness when all regions are controlled to the same target temperature to form a film. Although all regions are controlled to the same temperature, the film thickness of each region does not match the target value, and there is a deviation between the regions. Figure 2 In (b) and (c), the target temperature of each area is changed respectively, and the heaters 60a to 60f are controlled in each area so as to reach the respective target temperatures, thereby making the film thickness in each area consistent with or close to the target value. When the deviation of the film thickness from the target value is controlled by temperature regulation in this way, the range in which the film thickness changes with the controllable temperature control resolution becomes the limit of regulation. Figure 2 (b) shows the film formation result when the temperature is adjusted in units of 0.1° C., which is the minimum digit (smallest digit) of the control limit of the heaters 60 a to 60 f. Figure 2 (c) shows the film formation result when the temperature is adjusted in units of 0.01°C. Figure 2 (c) In the temperature regulation during film formation, Figure 2 Compared with the temperature regulation during film formation of (b), the temperature that can be controlled is higher resolution. Figure 2 The film formation result shown in (c) can be compared with Figure 2 The film formation result shown in (b) more precisely adjusts the film thickness, and the film thickness in each region is more consistent with or close to the target value.

[0049] For example, Figure 2The temperature control of (b) is in 0.1°C units. Therefore, if 0.17°C is subtracted from the current temperature value of "CTR2" to control the heater 60, even if the film thickness is consistent with the target value, the film thickness cannot be consistent with the target value because -0.2°C is subtracted from the current temperature value for adjustment, and it deviates slightly from the target value. On the other hand, because Figure 2 The temperature control in (c) is performed in units of 0.01° C., so the heater 60 can be controlled by subtracting 0.17° C. from the current temperature value of “ CTR2 ”, and the film thickness can be made to match the target value.

[0050] Therefore, the temperature of each area in the processing (film formation) step performed by the substrate processing device 1 is changed in a pulsed manner, and the time before and after the change is divided by a ratio, thereby making the temperature control resolution finer than the control limit value (minimum value of the control limit) of the heating part to perform temperature control with a higher resolution. As a result, the inter-surface uniformity of the film thickness can be improved without changing the hardware structure of the substrate processing device 1.

[0051] Figure 3 1 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, in the case where it is desired to control the 30-minute film forming step to a target temperature of 500.07°C, the film forming step is divided into two steps of setting the temperature of 500.0°C and 500.1°C. The time ratio of each step is set in the processing scheme in a ratio of 3:7=9 minutes:21 minutes. Then, according to the processing scheme, in the 30-minute film forming step, the heater 60 is controlled to 500.0°C for 9 minutes in step I, and the heater 60 is controlled to 500.1°C for 21 minutes in step II. As a result, the heater 60 can be controlled to a target temperature of 500.07°C for the substrate in the film forming step.

[0052] Thus, without changing the hardware structure of the substrate processing apparatus 1, the temperature can be controlled with a control resolution of 0.01°C or less (0.001°C, etc.) in a temperature control structure in which the control limit value of the heater 60 is 0.1°C.

[0053] Figure 4 is a conceptual diagram of a temperature control method according to an embodiment. Figure 4 (a) The target temperature before optimization, Figure 4 In the temperature control method of the conventional example (b), the optimization software is used to find the optimal temperature change amount from the "TOP" to the "BTM" area, and the optimal temperature change amount is added to the target temperature of each area for optimization. Figure 4 In the temperature control method of this embodiment (c), for Figure 4The target temperature before optimization of (a) is calculated, and the temperature optimization of each area is realized in the same way as in the previous example. Figure 3 The temperature change times (for example, 9 minutes and 21 minutes) for the temperatures (500.0° C., 500.1° C.) are given as an example.

[0054] Specifically, first, the target temperature is calculated with an arbitrary number of digits. Figure 4 In (a), 850°C is calculated as the target temperature for the entire region. Figure 4 In (a), the film forming step is used as an example for explanation, but the same temperature control can also be performed in other substrate processing steps.

[0055] Figure 4 The calculation of the optimal temperature change for the target temperature of (b-1) and (c-1) is optimized using the quadratic programming method. The number of digits of the temperature calculated here can be determined by the user. In the previous example (i.e., the existing 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 the present embodiment, the number of digits set by the user is rounded. The quadratic programming method is a method for calculating the optimal (optimal) conditions. The quadratic programming method of the present embodiment is a method of using an optimization model (optimization software) to calculate the combination of each region of the optimal temperature change that reduces the gap (gap) from the target temperature before optimization. In the optimization model, it is specified how much the temperature of the substrate changes after the temperature of the "TOP" rises by 1°C, how much the film thickness changes after the temperature of the substrate rises by 1°C, etc.

[0056] In previous examples, Figure 4 As shown in (b-1), the temperature change of each area from "TOP" to "BTM" is calculated, as shown in Figure 4 As shown in (b-2), the heater 60 of each zone is independently controlled so that the value is obtained by adding the temperature change amount to the target temperature before optimization. Thus, "TOP" is controlled to 852°C based on the temperature change amount +2°C, "T / C" is controlled to 850°C based on the temperature change amount 0°C, "C / B" is controlled to 848°C based on the temperature change amount -2°C, and "BTM" is controlled to 846°C based on the temperature change amount -4°C. Among them, "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.

[0057] In this embodiment, if Figure 4 As shown in (c-1) of FIG. 1 , the temperature change in each area from "TOP" to "BTM" is calculated in the unit determined by the user (here, the unit is 0.01°C (the second decimal place)). Figure 4 The temperature change shown in (c-1) is divided into Figure 4The sum of the values ​​to the first decimal place shown in (c-1-1) Figure 4 The value of the second decimal place shown in (c-1-2) is the control limit value of the heater 60, and the number of digits of the control limit value is the minimum digit (minimum digit) of the control limit of the heater 60. Figure 4 The numerical value shown in (c-1-2) is a numerical value of the second decimal place, and the numerical value of the second decimal place is a numerical value exceeding the control limit of the heater 60.

[0058] Figure 4 The numerical value to the first decimal place shown in (c-1-1) is the same as in the previous example, such as Figure 4 As shown in (c-2-1), the heater 60 of each zone is independently controlled so as to obtain a value obtained by adding the temperature change amount to the target temperature before optimization. Thus, "TOP" is controlled to 852°C based on the temperature change amount +2°C, "T / C" is controlled to 850°C based on the temperature change amount 0°C, "C / B" is controlled to 848°C based on the temperature change amount -2°C, and "BTM" is controlled to 846°C based on the temperature change amount -4°C.

[0059] Simultaneously with this control, a pulse output is performed that matches the temperature change timing (see Figure 4 (c-2-2)). For example, "TOP" is divided into two steps of setting the temperature of 852.00°C and 852.10°C. The time ratio of each step is set to a ratio of 2:8 in the processing scheme. Then, according to the processing scheme, the heater 60 is controlled to 852.00°C at the first time of step I in the film forming step, and the heater 60 is controlled to 852.10°C at the second time of step II. Thus, the heater 60 can be controlled to a target temperature of 852.02°C for the substrate in the film forming step. Thus, "TOP" is controlled to 852°C+0.02°C. Other areas are controlled in the same way. Thus, temperature control can be performed in each area with a precision finer than the control limit value of the heater 60 (here, the first decimal place).

[0060] The value up to the first decimal place of the control limit value of the heater 60 is notified to the user as the temperature set by the substrate processing apparatus 1. The value below the second decimal place of the control limit value of the heater 60 is used as the reference value. Figure 3 The temperature control method described herein calculates the temperature change time and notifies the user. The user sets the optimized temperature and pulse-shaped temperature change time based on the notified temperature change amount in the processing plan. Alternatively, the optimized temperature and pulse-shaped temperature change time based on the notified temperature change amount can also be automatically set in the processing plan. The control device 100 performs the film forming step according to the processing plan.

[0061] By manually or automatically setting the processing recipe, the film forming step is divided into (number of zones + 1) steps, and the temperature change amount can be controlled at different times for each zone. Figure 5 is an explanatory diagram of a temperature control method according to an embodiment. Figure 5 In the example of , the time for changing the temperature in each region is different, so the film forming step is divided into 7 steps obtained by adding 1 to the number of 6 regions from "TOP" to "BTM", so that the temperature can be changed in each region. Figure 5 Although they are represented equally in the figure, they may also be changed according to the temperature change timing of the pulses in each area.

[0062] [Temperature control method]

[0063] Reference Figure 6 , a temperature control method according to one embodiment is described. Figure 6 1 is a flowchart showing an example of a temperature control method according to an embodiment. The temperature control method according to this embodiment is controlled by the control device 100 and executed by the substrate processing apparatus 1 .

[0064] In step S1, the control device 100 obtains a target temperature. Figure 4 In the example (a), 850° C. is acquired as the target temperature of each step of the film forming step. In addition, the control device 100 acquires a second digit smaller than the first digit which is the minimum digit of the temperature control limit. The second digit is determined in advance by the user.

[0065] Next, in step S2, the control device 100 uses an optimization model (optimization software) to calculate the temperature change amount in each area. Figure 4 In the example (c-1), the temperature change amount is calculated for each area.

[0066] Next, in step S3, the control device 100 divides the target temperature into a first temperature higher than the first digit representing the minimum digit of the control limit of the heater 60 and a second temperature of the second digit smaller than the first digit for each area. Figure 4 In the example of (c-1), Figure 4 The value to the first decimal place shown in (c-1-1) is taken as the first temperature. Figure 4 The value of the second digit (the second decimal place) smaller than the first digit shown in (c-1-2) is taken as the second temperature.

[0067] Next, in step S4, the control device 100 calculates the ratio of the time length (film forming time) into the first time corresponding to the second temperature and the second time outside it, wherein the time length is divided into multiples corresponding to the difference in order of magnitude between the first digit and the second digit.

[0068] For example, in Figure 4 In the example of (c-1), the first digit is the first decimal place, and the second digit is the second decimal place. Figure 4 The second temperature "+0.02°C" as the temperature change amount of the "TOP" region shown in (c-1-2) is divided into a multiple of the time length corresponding to the difference in order of magnitude between the first and second digits (i.e., 1 / 10) and is a pulse of two levels corresponding to the second temperature +0.02°C. That is, the film forming 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 this at a ratio of 1:4, and the temperature control is performed in a pulsed manner.

[0069] Next, in step S5, the control device 100 controls the first temperature to a temperature that is changed according to the temperature change amount of each area. Figure 4 In (c-2-1), the first temperature (850°C) is controlled to be 852°C, 850°C, 848°C, and 846°C, which are changed according to the temperature change amount in each region from "TOP" to "BTM".

[0070] Furthermore, the control device 100 controls the first time to be a value obtained by adding 1 to the minimum digit of the first temperature, and controls the second time to be the first temperature. Figure 4 In (c-2-2), the first time is controlled to be a value (850.1°C) obtained by adding 1 to the minimum digit (first decimal point) of the first temperature (850°C), and the second time is controlled to be the first temperature (850.0°C). The ratio of the first time to the second time is 1:4. The control device 100 may also control the first temperature to be a value (852.1°C) obtained by adding 1 to the minimum digit (first decimal point) of the temperature after the temperature change amount in each area (for example, 852°C in "TOP"), and control the second time to the changed temperature (852.0°C).

[0071] Therefore, for the target temperature of 850°C, in the case of the "TOP" region, in order to perform temperature control of 850.02°C with the temperature change added, 850.1°C (or 852.1°C) is controlled at a ratio of 2 / 10, and 850.0°C (or 852.0°C) is controlled at a ratio of 8 / 10. As a result, the temperature of the "TOP" region can be controlled to 852.02°C after temperature optimization. As a result, the temperature can be controlled to a value lower than the control limit (at Figure 4In the example, the first decimal point) is the lower digit (in Figure 4 In the example, the second decimal place).

[0072] Next, in step S6, the control device 100 puts the substrate into the processing container for preparation and performs film forming treatment. The substrate can also be prepared before step S6.

[0073] Next, in step S7, the control device 100 determines whether the film forming result is the desired result. If the control device 100 determines that the film forming result is the desired result, the present process is terminated. If the control device 100 determines that the film forming result is not the desired result, the control device 100 returns to step S1 and performs the process after step S1 again.

[0074] [Effect]

[0075] Reference Figure 7 , an example of a predicted value (value of a simulation result) and a measured value (value of an experimental result) for a target film thickness in one embodiment is described. Figure 7 This is a diagram showing an example of predicted values ​​and measured values ​​for a target film thickness in one embodiment.

[0076] Figure 7 (a) is a graph that represents the temperature change in each area from "TOP" to "BTM" for the target temperature before optimization adjustment using the temperature control method of this embodiment, in a standardized manner, wherein "TOP" is set to "0.00". When the control limit value is 0.1°C unit, because the temperature control method of this embodiment is used, the temperature change is 0.01°C unit. In addition, the temperature change can also be controlled in units finer (smaller) than 0.01°C units. For example, when controlled to 500.012°C in 0.001°C units, in the film forming step, it is carried out at a ratio of 500.0°C to 88 / 100 and 500.1°C to 12 / 100.

[0077] When the temperature change is controlled in units of 0.01°C, the inter-surface uniformity of the predicted value of the film thickness (predicted film thickness) predicted by simulation is 0.43%, which is better than the inter-surface uniformity of the measured value of the film thickness (measured film thickness) measured before optimization adjustment, which is 0.50%.

[0078] When the temperature change was controlled in units of 0.01°C, the inter-surface uniformity of the measured value of the film thickness (measured film thickness) when film formation was carried out using the substrate processing device 1 was 0.45%, which was better than the inter-surface uniformity of the measured value of the film thickness (measured film thickness) before optimization adjustment, which was 0.50%.

[0079] Figure 7 The horizontal axis of (b) is the slot number of the wafer boat 48. The slot numbers are assigned in ascending order starting from the top of "TOP". Figure 7 The vertical axis of (b) represents the relative film thickness relative to the target film thickness. The target film thickness is represented by a solid line, is set to 1, and is standardized.

[0080] The surface uniformity of the predicted film thickness and the measured film thickness when optimized in 0.01°C units was improved compared to the surface uniformity of the measured film thickness before optimization. In addition, the surface uniformity of the predicted film thickness and the measured film thickness when optimized in 0.01°C units was better than the surface uniformity of the predicted film thickness when optimized in 0.1°C units.

[0081] As described above, according to the temperature control method and substrate processing device of the present embodiment, it is possible to perform temperature control in the substrate processing device with a finer accuracy than the control limit value of the heating portion. Therefore, by performing temperature control with a finer temperature resolution, it is possible to achieve an improvement in the inter-surface uniformity of the film thickness compared to the usual temperature regulation. As a result, the inter-surface uniformity of the film thickness is improved, thereby improving the yield rate. As a result, by improving the yield rate, it is possible to expect a reduction in money and time costs. In addition, it can contribute to the further miniaturization of semiconductors.

[0082] In addition, according to the temperature control method of this embodiment, it is possible to adjust the inter-surface uniformity of the film thickness with higher precision without modifying the hardware structure of the substrate processing device 1 (usual application range). In addition, by using the optimization software (optimization model), in addition to the temperature change amount in 0.1°C units, the temperature change time suitable for any control digit can be calculated. In addition, temperature control that is finer than the second decimal place can be performed by making the unit of the divided time finer (for example, 1:99, etc.).

[0083] In the above embodiment, temperature control is described, but in gas flow rate and pressure control, by performing the same gas flow rate control and pressure control as the above temperature control, gas flow rate control and pressure control can be performed with a finer accuracy than the control limit of the substrate processing device 1.

[0084] The temperature control method and substrate processing device of the embodiments described in this specification should be considered to be illustrative in all aspects and not restrictive. The embodiments can be deformed and improved in various ways without departing from the content of the invention and its main purpose. The matters described in the above-mentioned multiple embodiments can also adopt other structures within the scope of non-contradiction, and can be combined within the scope of non-contradiction.

[0085] In the above-mentioned embodiment, it is described that the substrate processing apparatus of this embodiment is a batch film forming apparatus that processes a plurality of substrates at a time, but the present invention is not limited to this. The substrate processing apparatus of this embodiment may also be a single-wafer film forming apparatus that processes wafers one by one. In addition, the substrate processing apparatus may also be a semi-batch film forming apparatus that uses a rotating table to make a plurality of wafers arranged on a rotating table in a processing container revolve, so that the plurality of wafers sequentially pass through an area supplied with a first gas and an area supplied with a second gas to process the wafers. In addition, the substrate processing apparatus may also be a plurality of single-wafer film forming apparatuses in which a plurality of mounting tables are arranged in one processing container.

Claims

1. A temperature control method, characterized in that: The temperature control method is performed by a substrate processing device, The substrate processing device comprises: a processing container, which can carry substrates into and out of the processing container; and a heating unit capable of heating the inside of the processing container. The temperature control method comprises: a step of setting a temperature change amount with respect to a target temperature, wherein the target temperature has a value up to a second digit smaller than a first digit representing a control limit value of the heating unit; b. dividing the temperature change into a first temperature above the first digit and a second temperature less than the first digit, and calculating a ratio of a time length divided into a first time corresponding to the second temperature and a second time other than the first temperature, wherein the time length is divided into multiples corresponding to the difference in order of magnitude between the first digit and the second digit; and In step c, the heating unit is controlled so that the temperature varies up and down before and after the time of the substrate processing step is divided according to the ratio.

2. The temperature control method according to claim 1, characterized in that: In the step c, the first time of the preceding and following times divided according to the ratio is controlled to be a value obtained by adding 1 to the first digit of the first temperature, and the second time is controlled to be the first temperature.

3. The temperature control method according to claim 1, characterized in that: The substrate processing device includes a wafer boat, which holds a plurality of the substrates in a plurality of grooves arranged in multiple layers in a vertical direction and can be carried into and out of the processing container. In steps a to c, when the multiple grooves are divided into multiple zones, the temperature change amount is set for the target temperature for each zone, and the heating unit of each zone is independently controlled so that the temperature of each zone changes up and down before and after the time divided according to the ratio.

4. The temperature control method according to any one of claims 1 to 3, characterized in that: In the step c, the heating unit is controlled to a value obtained by adding the first temperature to the target temperature in the processing step, and the heating unit is controlled so that the temperature varies up and down before and after the time divided into the processing step time according to the ratio.

5. The temperature control method according to any one of claims 1 to 3, characterized in that: include: Step d, preparing a substrate in the processing container, and performing processing on the substrate in the processing step.

6. A substrate processing device, characterized in that: include: a processing container capable of transferring substrates into and out of the processing container; A heating unit capable of heating the inside of the processing container; and A control unit controls the steps including step a, step b and step c, wherein: The step a is to set a temperature change amount with respect to a target temperature, wherein the value of the target temperature has a value up to a second digit smaller than a first digit representing a control limit value of the heating unit; In step b, the temperature change is divided into a first temperature above the first digit and a second temperature below the first digit, and a ratio of a time length divided into a first time corresponding to the second temperature and a second time outside the first temperature is calculated, wherein the time length is divided into multiples corresponding to the difference in order of magnitude between the first digit and the second digit; In the step c, the heating unit is controlled so that the temperature varies up and down before and after the time of the substrate processing step is divided according to the ratio.

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