Deposition state monitoring method and substrate processing apparatus

Abstract

To provide a technique capable of early and easily estimating the deposition state of a pump.SOLUTION: A deposition state monitoring method capable of monitoring the deposition state of a deposit deposited on a pump connected to the treatment vessel of a substrate treatment apparatus for treating a substrate comprises the steps of: acquiring the current value of a motor for rotating the rotational structure of the pump; generating an attenuated waveform in the time change of the current value by supplying raw gas to the treatment vessel; acquiring the peak current values of a plurality of peak parts constituting the attenuated waveform and the bottom current values of trough parts having the same number as the plurality of peak parts; calculating an estimated convergence current value obtained by converging the attenuated waveform of the current value by averaging the peak current values of the plurality of peak parts and the bottom current values of the plurality of trough parts; and estimating the deposition state of the deposit on the basis of the estimated convergence current value.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a deposition state monitoring method and a substrate processing apparatus. [Background technology]

[0002] Substrate processing apparatuses used in semiconductor manufacturing exhaust processing gases from a processing chamber using a turbomolecular pump. During exhaust, deposits such as reaction products generated during substrate processing and by-products that do not contribute to substrate processing accumulate on the turbomolecular pump. Patent Document 1 discloses a technology in which a control device monitors the current value supplied to the turbomolecular pump to estimate the state of deposits on the turbomolecular pump.

[0003] In estimating the deposition state, since the accuracy of estimation decreases when the current value of the turbomolecular pump is small, the current value when the processing gas is introduced into the processing vessel and a load is applied to the turbomolecular pump is used. At the start of the introduction of the processing gas, the current value supplied to the turbomolecular pump forms a decaying waveform that suddenly increases and then gradually converges with repeated amplitudes. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2021-179187 Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure provides a technique that allows for early and easy estimation of the state of deposition in a pump. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, a pump connected to a processing vessel of a substrate processing apparatus for processing a substrate Inside 1. A method for monitoring a deposition state of a deposit deposited on a surface of a substrate, comprising: The pump is connected to the processing vessel and evacuates the internal space of the processing vessel, thereby introducing the processing gas supplied to the internal space into the pump. The control unit controlling the pump: (a) acquiring a current value of a motor that rotates a rotating structure of the pump; and (b) The aforementioned (c) acquiring peak current values ​​of a plurality of peak portions constituting the decay waveform and bottom current values ​​of the same number of valley portions as the plurality of peak portions; (d) calculating an estimated convergence current value at which the decay waveform converges by averaging the acquired peak current values ​​of the plurality of peak portions and bottom current values ​​of the plurality of valley portions; and (e) calculating an estimated convergence current value at which the decay waveform converges based on the estimated convergence current value. Inside the pump a step of estimating the deposition state of the deposit; control A deposition condition monitoring method is provided. [Effects of the Invention]

[0007] According to one aspect, the state of accumulation in the pump can be estimated early and easily. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic cross-sectional view illustrating an example of a substrate processing apparatus according to an embodiment. [Figure 2] 1 is a cross-sectional view schematically showing a turbomolecular pump provided in a substrate processing apparatus. [Figure 3] FIG. 2 is a block diagram showing functional blocks of a control unit that estimates the deposition state of a turbomolecular pump. [Figure 4] 10 is a graph illustrating motor current data stored in a storage area. [Figure 5] FIG. 10 is an explanatory diagram showing a process of calculating an average value from motor current data. [Figure 6] 1 is a flowchart showing a processing flow of a deposition state monitoring method. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments 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 redundant explanations may be omitted.

[0010] Fig. 1 is a cross-sectional view showing an example of a substrate processing apparatus 1 according to an embodiment. As shown in Fig. 1, the substrate processing apparatus 1 is an inductively coupled plasma (ICP) processing apparatus that performs various substrate processes on an FPD substrate (hereinafter simply referred to as substrate G) made of a glass material. Examples of FPDs manufactured by processing the substrate G include liquid crystal displays (LCDs), electroluminescence (EL), and plasma display panels (PDPs). Note that, in addition to glass, synthetic resins and the like can also be used as materials for the substrate G.

[0011] The substrate G may be either a substrate having a circuit patterned on its surface, or a support substrate without a circuit. The planar dimensions of the substrate G are preferably such that the long side is in the range of approximately 1800 mm to 3400 mm and the short side is in the range of approximately 1500 mm to 3000 mm. The thickness of the substrate G is preferably in the range of approximately 0.2 mm to 4.0 mm. Examples of substrate processing performed by the substrate processing apparatus 1 include film formation processing using a CVD (Chemical Vapor Deposition) method and etching processing. The following description will be given taking the substrate processing apparatus 1 performing film formation processing as an example of substrate processing.

[0012] The substrate processing apparatus 1 includes a rectangular parallelepiped box-shaped processing vessel 10. The processing vessel 10 is made of a metal such as aluminum or an aluminum alloy. The processing vessel 10 may be formed into an appropriate shape depending on the shape of the substrate G. For example, when the substrate G is a circular plate or an elliptical plate, the processing vessel 10 is preferably formed into a cylindrical shape, an elliptical cylindrical shape, or the like.

[0013] The processing vessel 10 is provided with a rectangular support frame 11 that protrudes inward of the processing vessel 10 at a predetermined vertical position, and this support frame 11 supports a dielectric plate 12 in the horizontal direction. The processing vessel 10 is divided into an upper chamber 13 and a lower chamber 14, sandwiched between the dielectric plate 12. The upper chamber 13 defines an antenna chamber 13a therein. The lower chamber 14 accommodates a substrate G and defines an internal space 14a therein where the substrate is processed.

[0014] A side wall 15 of the lower chamber 14 is provided with a loading / unloading port 17 that is opened and closed by a gate valve 16. When the gate valve 16 is open, the substrate processing apparatus 1 loads and unloads the substrate G through the loading / unloading port 17 by a transfer device (not shown).

[0015] In addition, the side walls 15 of the lower chamber 14 are grounded (connected to ground potential) via a ground wire 18. Each of the four side walls 15 of the lower chamber 14 has an endless circumferential seal groove 19 at its upper end. A seal member 20 such as an O-ring is placed in the seal groove 19, thereby airtightly sealing the internal space 14a of the support frame 11 and the lower chamber 14.

[0016] The support frame 11 is made of a metal such as aluminum or an aluminum alloy, etc. The dielectric plate 12 is made of a ceramic such as alumina (Al2O3) or quartz.

[0017] A shower head 21, which is connected to the support frame 11 and consists of a plurality of elongated members, is provided inside the support frame 11 and discharges processing gas into the internal space 14a, and also serves as a support beam for supporting the dielectric plate 12. The dielectric plate 12 is supported on the upper surface of the shower head 21. The shower head 21 is preferably made of a metal such as aluminum and has been subjected to a surface treatment by anodization. A gas flow path 21a is formed inside the shower head 21 along the horizontal direction. The shower head 21 also has a plurality of gas discharge holes 21b that communicate between the gas flow path 21a and the lower surface of the shower head 21 (internal space 14a).

[0018] A gas introduction pipe 22 communicating with the gas flow path 21a is connected to the upper surface of the shower head 21. The gas introduction pipe 22 extends upward within the upper chamber 13, penetrates the upper chamber 13, and is connected to a gas supply unit 23 provided outside the processing vessel 10.

[0019] Gas supply unit 23 has a gas supply path 24 connected to gas inlet pipe 22, and is equipped with, in this order from upstream to downstream of gas supply path 24, a gas supply source 25, a mass flow controller 26, and an on-off valve 27. In a film formation process, a processing gas is supplied from gas supply source 25, the flow rate of which is controlled by mass flow controller 26, and the supply timing of which is controlled by on-off valve 27. This processing gas flows from gas supply path 24 through gas inlet pipe 22 into gas flow path 21a and is then released into internal space 14a through each gas discharge hole 21b.

[0020] A high-frequency antenna 28 is installed in the upper chamber 13, which forms the antenna chamber 13a. The high-frequency antenna 28 is configured by wiring an antenna wire made of a conductive metal such as copper in a circular or spiral shape. Alternatively, the high-frequency antenna 28 may be configured by installing multiple circular antenna wires. A power supply member 29 extending upward within the upper chamber 13 is connected to the terminals of the high-frequency antenna 28.

[0021] The power supply member 29 has an upper end that protrudes outside the processing vessel 10, and a high-frequency power supply unit 30 is connected to this upper end. The high-frequency power supply unit 30 has a power supply line 30a, which is connected to a high-frequency power supply 32 via a matching box 31 that performs impedance matching. The high-frequency power supply 32 applies high-frequency power of a frequency (e.g., 13.56 MHz) appropriate for the substrate processing to the high-frequency antenna 28. As a result, the high-frequency antenna 28 forms an induced electric field within the lower chamber 14.

[0022] The processing vessel 10 includes a stage 40 (mounting table) in the lower chamber 14 on which the substrate G loaded through the loading / unloading port 17 is placed. The stage 40 has a stage main body 41, a pedestal 42, a plurality of lift pins 43, and a plurality of lift pin lifting mechanisms 44. The substrate G loaded into the lower chamber 14 is transferred to each of the lift pins 43 raised by each of the lift pin lifting mechanisms 44, and is placed on the stage main body 41 by lowering each of the lift pins 43.

[0023] The stage main body 41 is formed in a rectangular shape in a plan view, and has a mounting surface 411 with planar dimensions approximately the same as those of the substrate G. For example, the planar dimensions of the mounting surface 411 may be such that the long side is in the range of approximately 1800 mm to 3400 mm, and the short side is in the range of approximately 1500 mm to 3000 mm.

[0024] A plasma processing space PCS is formed between the mounting surface 411 of the stage body 41 and the shower head 21. In the plasma processing space PCS, plasma is generated by converting the processing gas supplied from the shower head 21 into plasma due to an induction electric field formed by the high-frequency antenna 28. The substrate processing apparatus 1 deposits a film formation precursor in the plasma generated in the plasma processing space PCS onto the substrate G. Note that a metal plate may be used instead of the dielectric plate 12 to form an induction electric field via the metal plate and generate plasma. In this case, no support beam is required, and the metal plate can also serve as a shower head.

[0025] The stage body 41 is made of aluminum, an aluminum alloy, or the like, and includes a temperature control mechanism for adjusting the temperature of the substrate G. For example, the temperature control mechanism includes a heater wire 45, which is a resistor, inside the stage body 41, and a temperature control power supply unit 46, which supplies power to the heater wire 45, outside the processing chamber 10. Alternatively, the temperature control mechanism may include a flow path for circulating a coolant inside the stage body 41 and a chiller for supplying the coolant to the flow path (both not shown). For example, during substrate processing (film formation processing), the substrate processing apparatus 1 controls the temperature of the mounting surface 411 of the stage 40 to about 200°C by heating with the heater wire 45, and maintains that temperature state. Alternatively, the substrate G may be heated by circulating a heated temperature control medium through the flow path.

[0026] The pedestal 42 is made of an insulating material and is disposed on the bottom wall 33 of the lower chamber 14 to support the stage body 41. The pedestal 42 has an opening at its bottom, and fixes and supports the stage body 41 while keeping the stage body 41 spaced apart from the bottom wall 33. The pedestal 42 may have a structure that can be separated into a lower member that supports the stage body 41 and an upper member that surrounds the side surfaces of the stage body 41. Furthermore, the stage 40 is equipped with a bias power supply unit (not shown) that supplies high-frequency power to form a bias for drawing plasma toward the stage 40 during substrate processing.

[0027] The substrate processing apparatus 1 has an exhaust port 33a in the bottom wall 33 of the processing vessel 10 for exhausting gas from the internal space 14a, and also includes an exhaust unit 50 connected to the processing vessel 10 via the exhaust port 33a. Although one exhaust port 33a and one exhaust unit 50 are illustrated in FIG. 1, the substrate processing apparatus 1 may include exhaust ports 33a and exhaust units 50 at multiple locations.

[0028] The exhaust port 33a is formed in a perfect circle shape and is provided between the sidewall 15 of the processing vessel 10 and the stage 40. The diameter of the exhaust port 33a depends on the size of the processing vessel 10, but is preferably set in the range of, for example, about 200 mm to 400 mm, and is set to 300 mm in this embodiment. The shape of the exhaust port 33a does not have to be perfect circle, and may be formed in a shape such as a semicircle depending on the arrangement position.

[0029] The substrate processing apparatus 1 also includes a plurality of baffle plates 34 on the outer periphery of the stage 40 and between the plasma processing space PCS and the exhaust port 33a. Each baffle plate 34 imparts conductance to the processing gas around the stage 40 to guide the exhaust direction. The baffle plates 34 (and the sidewall 15 of the lower chamber 14) are connected to a ground potential and function as counter electrodes for the high-frequency bias power.

[0030] The exhaust unit 50 includes an exhaust pipe 51 connected to the exhaust port 33a, and an exhaust mechanism 52 provided in the exhaust pipe 51 to exhaust the processing gas (processing gas that has not contributed to the processing of the substrate) inside the processing vessel 10. The exhaust unit 50 may also include an exhaust mesh 35 at the connection portion (or the exhaust port 33a) between the processing vessel 10 and the exhaust pipe 51 to prevent components from falling.

[0031] The exhaust mechanism 52 reduces the pressure in the internal space 14a of the processing vessel 10 by exhausting the gas. The exhaust mechanism 52 also exhausts reaction products (deposits) generated during substrate processing together with the processing gas. Specifically, the exhaust mechanism 52 includes, in this order downstream of the exhaust pipe 51 in the flow direction of the processing gas, an automatic pressure control (APC) valve 53, a turbo molecular pump (TMP) 54, and a dry pump 55. The exhaust mechanism 52 performs rough evacuation of the processing vessel 10 using the dry pump 55, and then evacuates the processing vessel 10 using the turbo molecular pump 54. The exhaust mechanism 52 controls the pressure in the internal space 14a by adjusting the aperture of the APC valve 53.

[0032] The operation of each component of the exhaust mechanism 52 (APC valve 53, turbo molecular pump 54, dry pump 55) is controlled by a control unit 60. The control unit 60 is a control computer including one or more processors 61, a memory 62, an input / output interface (not shown), and electronic circuits. A user interface 65 is also connected to the control unit 60, which notifies the user of information about the substrate processing apparatus 1 and allows the user to input information.

[0033] The processor 61 is one or a combination of a central processing unit (CPU), a graphics processing unit (GPU), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a circuit made up of a plurality of discrete semiconductors, etc. The memory 62 is an appropriate combination of volatile memory and non-volatile memory (e.g., a compact disc, a digital versatile disc (DVD), a hard disk, a flash memory, etc.). The user interface 65 may be a monitor, a speaker, an alarm lamp, a keyboard, a mouse, a touch panel, etc.

[0034] The memory 62 stores a program for operating the substrate processing apparatus 1 and a recipe such as process conditions for substrate processing. The processor 61 reads and executes the program from the memory 62 to control each component of the substrate processing apparatus 1. For example, in controlling the turbomolecular pump 54, the control unit 60 calculates a target rotation speed of a motor 549 of the turbomolecular pump 54 so that the pressure inside the processing chamber 10 becomes a target pressure, and outputs the calculated target rotation speed to a driver 56 (see FIG. 2). As a result, the driver 56 supplies power according to the target rotation speed to the motor of the turbomolecular pump 54, thereby controlling the drive of the turbomolecular pump 54.

[0035] 2 is a cross-sectional view schematically showing a turbomolecular pump 54 provided in the substrate processing apparatus 1. The turbomolecular pump 54 is configured by fixing a base 541 and a casing 542 to each other, and houses a rotating structure 543 in the space inside. The rotating structure 543 has an umbrella-shaped pump rotor 544 and a shaft 545 that supports the center of rotation of the pump rotor 544.

[0036] A plurality of rotor blades 544a are formed on the outer peripheral surface of pump rotor 544 facing casing 542, protruding in a direction perpendicular to the axial direction of shaft 545 (diametrically outward). Meanwhile, a plurality of stator blades 542a are formed on the inner peripheral surface of casing 542, each positioned between adjacent rotor blades 544a. Rotor blades 544a and stator blades 542a form a turbo pump region that draws gas through an opening in casing 542.

[0037] Furthermore, a cylindrical portion 544b having a spiral groove on its outer circumferential surface is formed on the base 541 side of pump rotor 544. Meanwhile, the inner circumferential surface of base 541 facing cylindrical portion 544b is sufficiently close to cylindrical portion 544b, narrowing the gas flow path. Cylindrical portion 544b and the inner circumferential surface of base 541 form a spiral pump region that guides gas from the turbo pump region to exhaust port 546 of base 541.

[0038] A shaft 545 of the rotating structure 543 is supported in a non-contact manner by a plurality of magnetic bearings 547 provided on the base 541. Each magnetic bearing 547 includes an electromagnet and a displacement sensor, and the displacement sensor detects the levitation position of the shaft 545. The turbomolecular pump 54 also includes a rotation sensor 548 in the base 541 that detects the rotation speed (number of rotations per second) of the shaft 545.

[0039] Base 541 and shaft 545 are provided with motor 549 that rotates shaft 545. Motor 549 is formed by motor stator 549a on the base 541 side and motor rotor 549b on the shaft 545 side. Motor 549 rotates rotating structure 543 at high speed around the axis of shaft 545. This allows pump rotor 544 to guide gas on the opening side to the turbo pump region and the spiral pump region in that order, and discharge it from exhaust port 546.

[0040] The driver 56 receives a command for a target rotation speed from the control unit 60 and adjusts the power supplied to the motor 549. At this time, the driver 56 detects the actual rotation speed using a rotation sensor 548 and performs feedback control, thereby rotating the motor 549 so that the actual rotation speed approximately matches the target rotation speed. The control unit 60 also receives information about the actual current supplied to the motor 549 from the driver 56 or a current sensor 57 provided in the wiring, thereby monitoring the actual current of the turbomolecular pump 54. The control unit 60 then estimates the deposition state of reaction products (deposits) deposited on the turbomolecular pump 54 based on the information about the actual current.

[0041] 3 is a block diagram showing functional blocks of the control unit 60 that estimates the deposition state of the turbomolecular pump 54. As shown in FIG. 3, the control unit 60 includes a pump control unit 70, a current acquisition unit 71, a memory area 72, a gas control unit 73, and a deposition state estimation unit 74.

[0042] The pump control unit 70 commands the driver 56 to set a target rotation speed for exhausting the processing gas so that the inside of the processing vessel 10 becomes a reduced pressure atmosphere set in the substrate processing recipe. In response to this, the driver 56 supplies appropriate power to the motor 549 of the turbo molecular pump 54 to rotate the rotating structure 543 substantially constantly at the target rotation speed. Furthermore, during substrate processing, the turbo molecular pump 54 operates continuously to maintain the predetermined reduced pressure atmosphere inside the processing vessel 10.

[0043] The current acquisition unit 71 acquires information on the actual current from the driver 56 or the current sensor 57, and stores motor current data D, which associates the information on the actual current with time information measured in the control unit 60, in a storage area 72. The storage area 72 is provided in one area of ​​the memory 62.

[0044] The gas control unit 73 controls the operation of the gas supply unit 23 to supply the processing gas into the processing vessel 10. The gas control unit 73 also outputs information on the supply state of the processing gas to the deposition state estimation unit 74. Examples of the supply state of the processing gas include the timing of starting the supply, the type of processing gas, and the supply amount (flow rate).

[0045] The deposition state estimation unit 74 estimates the deposition state of deposits in the turbomolecular pump 54 based on the current supplied to the motor 549 of the turbomolecular pump 54. To this end, the deposition state estimation unit 74 includes a current analysis unit 75 that analyzes the motor current data D, an estimation unit 76 that estimates the deposition state based on the analysis results of the current analysis unit 75, and a notification control unit 77 that prompts the user to perform maintenance, etc., based on the estimation results.

[0046] The current analysis unit 75 reads the motor current data D stored in the storage area 72, and extracts and processes information required for estimating the deposition state from the motor current data D. Specifically, the current analysis unit 75 reads the motor current data D at the timing when the supply of the processing gas starts, based on information on the supply state of the processing gas from the gas control unit 73. That is, in order to improve the estimation accuracy of the deposition state, the current analysis unit 75 uses a large current value when the processing gas is introduced into the processing vessel 10 and a load is applied to the turbomolecular pump 54.

[0047] FIG. 4 is a graph illustrating the motor current data D stored in the memory area 72. In the graph of FIG. 4, the horizontal axis represents time, and the vertical axis represents the current value or the flow rate of the process gas. As shown in FIG. 4, the motor current data D shows a sudden increase in current value with a slight time lag when the supply of the process gas starts. This is because, as the supply of the process gas increases, the flow rate of the process gas in the process vessel 10 also increases, which increases the flow rate of the process gas to be exhausted and increases the load on the turbomolecular pump 54 that sucks the process gas. Furthermore, after the sudden increase in current value, the motor current data D shows an attenuating waveform in which the current value gradually converges while repeating a series of rising and falling amplitudes over time.

[0048] In the motor current data D in Fig. 4, the peaks (highest points) of each mountain section and the bottoms (lowest points) of each valley section of the decay waveform are flat. This is because the current value is detected at each predetermined sampling period in the driver 56 or current sensor 57 of the turbo molecular pump 54. In other words, the motor current data D in Fig. 4 is formed as an interpolated waveform in which the current value transitions flat during the sampling period and this flatness of the current value suddenly changes at each sampling.

[0049] The sampling period for sampling the actual current in the driver 56 or the current sensor 57 is set to a time interval shorter than a half cycle of the decay waveform of the motor current data D. This sampling period is preferably set to an appropriate time interval by conducting experiments or simulations in advance. For example, the sampling period may be set to a range of about 1 second to 10 seconds.

[0050] As described above, the current analysis unit 75 uses the motor current data D obtained when the current value increases as the process gas is supplied to the process vessel 10. Because the motor current data D exhibits a decay waveform that repeats multiple amplitudes at the timing of the start of process gas supply, it takes a long time to extract the current value after the decay waveform has converged. For example, it takes approximately 90 seconds for the motor current to settle into a stable, flat waveform (i.e., a constant value) after the start of process gas supply. However, in substrate processing using the substrate processing apparatus 1, there are few processes in which the process gas is continuously supplied into the process vessel 10 at the same flow rate for 90 seconds or more. If the process gas flow rate is changed before the decay waveform of the motor current data D converges, a current value with a stable waveform cannot be obtained. This is also true when conditions such as the type of process gas are changed, not just the flow rate.

[0051] Therefore, the substrate processing apparatus 1 according to this embodiment is configured to predict the current value at which the decay waveform converges even during a period when the motor current data D is an unstable decay waveform. Specifically, the current analysis unit 75 extracts two peak current values ​​and two bottom current values ​​of the amplitude of the decay waveform at the timing when the supply of the processing gas starts, and calculates the average value using the current values ​​at a total of four points.

[0052] 5 is an explanatory diagram showing a process for calculating an average value from motor current data D. As shown in FIG. 5, the decay waveform of motor current data D oscillates over time in the following order: first peak 101, first valley 102, second peak 103, second valley 104, third peak 105, third valley 106, and so on. When focusing only on the peaks of motor current data D, the decay waveform basically shows a decrease in current value in the following order: peak of first peak 101, peak of second peak 103, peak of third peak 105, and so on. However, because driver 56 or current sensor 57 detects current at each sampling period regardless of the timing of the start of process gas supply, the order of peak heights (current values) between adjacent peaks may differ depending on the timing of sampling. Similarly, when focusing only on each valley of the motor current data D, the current value of the attenuation waveform basically increases in the order of the bottom of the first valley 102, the bottom of the second valley 104, the bottom of the third valley 106, etc. However, depending on the sampling timing, the order of the peak heights (current values) of adjacent valleys may also differ.

[0053] The current analysis unit 75 according to this embodiment extracts peak current values ​​of two peaks (first peak 101 and second peak 103) and bottom current values ​​of two valleys (first valley 102 and second valley 104) immediately after the start of the damping waveform of the motor current data D. The first peak 101 is a wave occurring when the current value first increases significantly as the supply of the process gas starts. The first valley 102 is a wave occurring when the current value decreases significantly relative to the first peak 101, adjacent to and continuous with the first peak 101. The second peak 103 is a wave occurring when the current value increases significantly relative to the second valley 104, adjacent to and continuous with the first valley 102. The second valley 104 is a wave occurring when the current value decreases significantly relative to the second peak 103, adjacent to and continuous with the second peak 103.

[0054] The current analysis unit 75 then calculates an average value (hereinafter referred to as an estimated convergence current value ES) from the four extracted current values, and regards this estimated convergence current value ES as the current value when the attenuation waveform converges. Note that the calculation of the average value from the four extracted current values ​​may be an arithmetic mean or a geometric mean.

[0055] Here, the present applicant conducted repeated experiments to confirm that the estimated convergence current value ES, which is the average of the peak current values ​​of multiple peaks and the bottom current values ​​of the same number of valleys, approximates the current value after the decay waveform converges. In other words, the decay waveform of the current of the turbomolecular pump 54 upon start of supply of process gas oscillates above and below the convergence current value because the load on the turbomolecular pump 54 and the reaction (torque) applied by the driver to suppress this load are balanced. Therefore, the estimated convergence current value ES, which is the average of the peak current values ​​of multiple peaks and the bottom current values ​​of the same number of valleys, represents the current value after the decay waveform converges with sufficient accuracy. This means that, for example, even when the peak current value of the first peak 101 is lower than the peak current value of the second peak 103 due to a difference in the current sampling period, it is possible to obtain approximately the same estimated convergence current value ES. This is because the bottom current value of the first valley 102 is higher than the bottom current value of the second valley 104 so as to match the peak current value of the first peak 101 and the peak current value of the second peak 103, and therefore, when the average is taken, it ultimately approximates the estimated convergence current value ES.

[0056] Furthermore, the current analysis unit 75 calculates the estimated convergence current value ES immediately after acquiring the peak current values ​​of the two set peaks and the bottom current values ​​of the two set valleys. For example, if the current acquisition unit 71 acquires current values ​​up to the third peak 105, it will be able to extract the peak current values ​​of the two peaks and the bottom current values ​​of the two valleys of the decay waveform. Therefore, the current analysis unit 75 calculates the estimated convergence current value ES immediately at the time of acquiring the current value of the third peak 105 from the four current values ​​up to that point, thereby obtaining the estimated convergence current value ES that approximates the current value after the decay waveform converges in a sufficiently short time.

[0057] The number of peaks from which peak current values ​​are extracted in the decay waveform is not limited to two and may be three or more, provided that the number is before the process gas conditions, such as the flow rate, are changed. Naturally, the number of valleys from which bottom current values ​​are extracted is also not limited to two and may be the same as the number of peaks. The greater the number of peaks and valleys from which the estimated convergence current value ES is calculated, the closer the estimated convergence current value ES is to the current value after the decay waveform converges. Furthermore, the current analysis unit 75 does not need to use the peaks and valleys immediately after the start of the decay waveform. For example, the current analysis unit 75 may obtain the estimated convergence current value ES using the peak current values ​​of the second peak 103 and the third peak 105 and the bottom current values ​​of the second valley 104 and the third valley 106. Alternatively, the current analysis unit 75 may monitor the decay waveform of the motor current data D and calculate the estimated convergence current value ES by excluding peaks and valleys with abnormal amplitudes. For example, if the peak current value of second peak portion 103 is abnormally low, current analysis unit 75 may use the peak current values ​​of first peak portion 101 and third peak portion 105 and the bottom current values ​​of first valley portion 102 and third valley portion 106 without extracting second peak portion 103 and second valley portion 104. Furthermore, if the value of first peak portion 101 is significantly larger than a predetermined value (a current value acquired previously), current analysis unit 75 may calculate estimated convergence current value ES using the bottom current value of first valley portion 102, the peak current value of second peak portion 103, the bottom current value of second valley portion 104, and the peak current value of third peak portion 105.

[0058] Returning to FIG. 3 , the estimation unit 76 estimates the deposition state of deposits in the turbomolecular pump 54 based on the process gas flow rate acquired from the gas control unit 73 and the estimated convergence current value ES calculated by the current analysis unit 75. The deposition state may be a numerical value representing the amount of deposits in the turbomolecular pump 54, or may be a value converted into a value representing the continuous operation period of the pump. For example, the control unit 60 stores in advance in the memory area 72 map information or a function that associates the process gas flow rate with the estimated convergence current value ES based on information about the deposition state of deposits in the turbomolecular pump 54. Then, upon receiving the process gas flow rate and the estimated convergence current value ES, the estimation unit 76 extracts or calculates the deposition state by referring to the memory area 72. As described above, the estimated convergence current value ES approximates the current value after the decay waveform converges, allowing the estimation unit 76 to accurately estimate the deposition state of the turbomolecular pump 54.

[0059] Furthermore, the notification control unit 77 outputs status information of the turbomolecular pump 54 to the user interface 65 based on the deposition state estimated by the estimating unit 76, and notifies the user of the status. For example, the notification control unit 77 may directly display the estimated deposition state (amount of deposits, duration of continuous operation, predicted maintenance timing, etc.) on the display unit of the user interface 65 as status information of the turbomolecular pump 54. Alternatively, the notification control unit 77 may have a maintenance threshold for comparison with the amount of deposits, and may issue a notification urging the user to perform maintenance on the turbomolecular pump 54 when the amount of deposits is equal to or greater than the maintenance threshold. Note that the estimated convergence current value ES itself may be treated as a numerical value indicating the deposition state, and, for example, the maintenance threshold may be set as a current value, and a notification urging the user to perform maintenance may be issued when the estimated convergence current value ES is equal to or greater than the current value set as the maintenance threshold.

[0060] The substrate processing apparatus 1 according to this embodiment is basically configured as described above, and its operation (deposition state monitoring method) will be described below with reference to Fig. 6. Fig. 6 is a flowchart showing the process flow of the deposition state monitoring method.

[0061] In preparation for substrate processing, the control unit 60 of the substrate processing apparatus 1 first opens the gate valve 16 and causes the transfer device to load the substrate G into the internal space 14a through the load / unload port 17. The control unit 60 then raises the lift pins 43 of the lift pin lifting mechanism 44 to receive the substrate G from the transfer device, and after the transfer device retreats, lowers the lift pins 43 to place the substrate G on the mounting surface 411 of the stage 40.

[0062] After the substrate G is placed, the control unit 60 of the substrate processing apparatus 1 starts substrate processing and, in conjunction with this, starts the deposition state monitoring method. The control unit 60 first operates the exhaust mechanism 52 of the exhaust unit 50 to exhaust gas from the internal space 14a of the processing vessel 10. At this time, the pump control unit 70 of the control unit 60 commands the driver 56 to set a target rotation speed for depressurizing the processing vessel 10 to a predetermined internal pressure, thereby rotating the turbo molecular pump 54 (motor 549) under current adjustment by the driver 56 (step S1). The rotation of the motor 549 is continuously controlled by the driver 56 so as to maintain a constant target rotation speed.

[0063] When the turbomolecular pump 54 is driven to rotate, the driver 56 or the current sensor 57 detects the actual current supplied from the driver 56 to the motor 549. Then, the current acquisition unit 71 of the control unit 60 acquires the actual current transmitted from the driver 56 or the current sensor 57 (step S2).

[0064] When the internal space 14a of the processing vessel 10 reaches a predetermined reduced pressure, the gas control unit 73 controls the gas supply unit 23 to supply the processing gas into the processing vessel 10 (step S3). This causes the flow rate of the processing gas inside the processing vessel 10 to increase rapidly (see time t0 in FIG. 5 ). The processing gas is ejected into the plasma processing space PCS through the gas ejection holes 21b of the shower head 21. As the processing gas is ejected, the substrate processing apparatus 1 supplies high-frequency power, for example, 13.56 MHz, from the high-frequency power supply 32 to the high-frequency antenna 28, thereby forming a uniform induction electric field in the plasma processing space PCS via the dielectric plate 12. The induction electric field thus formed converts the processing gas into plasma in the plasma processing space PCS, generating high-density inductively coupled plasma. As a result, the substrate processing apparatus 1 can perform substrate processing (film formation processing) to form a predetermined film on the substrate G.

[0065] In addition, the processing gas supplied to the plasma processing space PCS that did not contribute to the processing of the substrate, as well as reaction products and by-products (deposits) generated by the substrate processing, are sucked by the exhaust section 50 and exhausted from the exhaust port 33a through the exhaust pipe 51.

[0066] Based on the supply of processing gas into the processing vessel 10 during this substrate processing, the current acquisition unit 71 of the control unit 60 acquires an actual motor current having an attenuating waveform in which the motor current rises sharply and then repeats amplitude changes. When the deposition state estimation unit 74 receives the timing of the start of processing gas supply from the gas control unit 73, it reads and monitors the motor current data D from that timing onward. Then, the current analysis unit 75 of the deposition state estimation unit 74 extracts the peak current values ​​of the two peaks (first peak 101 and second peak 103) and the bottom current values ​​of the two valleys (first valley 102 and second valley 104) from the motor current data D (step S4).

[0067] After acquiring the set number (two) of peak current values ​​of the peak portions and the same number (two) of bottom current values ​​of the valley portions, the current analysis unit 75 calculates an estimated convergence current value ES by averaging them (step S5). For example, the current analysis unit 75 calculates the estimated convergence current value ES immediately after acquiring the set number of current values ​​(see time t1 in FIG. 5).

[0068] The estimation unit 76 then estimates the deposition state of the deposits in the turbomolecular pump 54 based on the flow rate of the process gas and the calculated estimated convergence current value ES (step S6). This allows the estimation unit 76 to accurately estimate the deposition state of the deposits in the turbomolecular pump 54 before the decay waveform converges. Therefore, the control unit 60 can accurately recognize the deposition state of the turbomolecular pump 54, for example, before the flow rate of the process gas in substrate processing, etc., is changed (see time t2 in FIG. 5).

[0069] The estimation unit 76 also compares the estimated amount of deposits with a maintenance threshold to determine whether maintenance of the turbomolecular pump 54 is required (step S7). If the amount of deposits is equal to or greater than the maintenance threshold (step S7: YES), the estimation unit 76 proceeds to step S8, and if the amount of deposits is less than the maintenance threshold (step S7: NO), the estimation unit 76 skips step S8.

[0070] In step S8, the notification control unit 77 notifies the user of information prompting maintenance of the turbomolecular pump 54 via the user interface 65. This allows the user to perform maintenance of the turbomolecular pump 54 at an appropriate time.

[0071] As described above, the substrate processing apparatus 1 and the deposition state monitoring method according to this embodiment estimate the deposition state of deposits on the turbomolecular pump 54 using the attenuation waveform of the current value supplied to the motor 549 of the turbomolecular pump 54. Therefore, the control unit 60 can estimate the deposition state in a short time from the start of supply of the processing gas to the processing vessel 10. For example, even if the flow rate of the processing gas varies depending on the substrate processing, the control unit 60 can stably and accurately estimate the deposition state.

[0072] The technical ideas and effects of the present disclosure explained in the above embodiments will be described below.

[0073] A first aspect of the present disclosure is a deposition state monitoring method for monitoring the deposition state of deposits deposited on a pump (turbomolecular pump 54) connected to a processing vessel 10 of a substrate processing apparatus 1 for processing a substrate G, comprising the steps of: (a) acquiring a current value of a motor 549 that rotates a rotating structure 543 of the pump; (b) generating a decay waveform in the time change of the current value by supplying processing gas to the processing vessel 10; (c) acquiring peak current values ​​of multiple peaks (first peak 101, second peak 103) that constitute the decay waveform and bottom current values ​​of the same number of valleys (first valley 102, second valley 104) as the multiple peaks; (d) calculating an estimated convergence current value ES at which the decay waveform converges by averaging the peak current values ​​of the multiple peaks and the bottom current values ​​of the multiple valleys; and (e) estimating the deposition state of the deposits based on the estimated convergence current value ES.

[0074] As described above, the deposition state monitoring method calculates the estimated convergence current value ES using the decay waveform of the pump (turbomolecular pump 54) current value, thereby enabling early and easy estimation of the deposition state of the pump. That is, the estimated convergence current value ES, which is the average of the multiple peaks (first peak 101, second peak 103) and multiple valleys (first valley 102, second valley 104) of the decay waveform, sufficiently approximates the current value after the decay waveform has converged. Therefore, the deposition state monitoring method can estimate the deposition state in substantially the same way as the current value after convergence, without waiting for the decay waveform to converge. This makes it possible, for example, to accurately grasp the deposition state before the flow rate of the process gas is changed during substrate processing.

[0075] In step (c), peak current values ​​of the multiple peaks (first peak 101, second peak 103) and bottom current values ​​of the multiple valleys (first valley 102, second valley 104) immediately after the start of the decay waveform are extracted. This allows the deposition state monitoring method to quickly estimate the deposition state after the process gas is supplied to the process vessel 10 and a decay waveform is generated in the current value.

[0076] Furthermore, step (d) is performed immediately after acquiring the peak current values ​​of the set number of peaks (first peak 101, second peak 103) and the bottom current values ​​of the valleys (first valley 102, second valley 104). This allows the deposition state monitoring method to estimate the deposition state immediately after repeating the peaks and valleys a set number of times, further shortening the time required for estimation.

[0077] In step (c), the peak current values ​​of the two peaks (first peak 101 and second peak 103) and the bottom current values ​​of the two valleys (first valley 102 and second valley 104) immediately after the start of the decay waveform are extracted. This allows the deposition state monitoring method to estimate the deposition state in a shorter time after the processing gas is supplied to the processing vessel 10.

[0078] In step (c), the bottom current values ​​of the valleys (first valley 102, second valley 104) adjacent to the peaks (first peak 101, second peak 103) for which the peak current values ​​were obtained are acquired. This enables the deposition state monitoring method to calculate the estimated convergence current value ES with even greater accuracy.

[0079] The method also includes a step of determining whether or not maintenance of the pump (turbomolecular pump 54) is necessary based on the deposition state of the deposits estimated in steps (f) and (e). This allows the deposition state monitoring method to appropriately notify the user of the timing of pump maintenance based on the estimated deposition state.

[0080] Furthermore, the pump (turbomolecular pump 54) is connected to the processing vessel 10 and evacuates the internal space 14a of the processing vessel 10, thereby introducing the processing gas supplied to the internal space 14a into the pump. Thus, even in a configuration in which reaction products (deposits) generated in the processing vessel 10 are deposited on the pump that evacuates the processing vessel, the deposition state monitoring method can stably monitor the deposition state of the pump.

[0081] A second aspect of the present disclosure is a substrate processing apparatus 1 for processing a substrate G, the apparatus including a processing vessel 10 for processing the substrate G, a pump (turbomolecular pump 54) connected to the processing vessel 10 and evacuating an internal space 14a of the processing vessel 10, and a controller 60, wherein the controller 60 performs the steps of: (a) acquiring a current value of a motor 549 that rotates a rotating structure 543 of the pump; and (b) supplying a processing gas to the processing vessel 10 to generate an attenuated waveform in the time change of the current value. (c) acquiring peak current values ​​of multiple peaks (first peak 101, second peak 103) constituting the decaying waveform and bottom current values ​​of valleys (first valley 102, second valley 104) adjacent to the multiple peaks and having the same number as the multiple peaks, (d) calculating an estimated convergence current value ES at which the decaying waveform converges by averaging the peak current values ​​of the multiple peaks and the bottom current values ​​of the multiple valleys, and (e) estimating the deposition state of the deposits based on the estimated convergence current value ES. Even in this case, the substrate processing apparatus 1 can quickly and easily estimate the deposition state of the pump.

[0082] The substrate processing apparatus 1 and the deposition state monitoring method according to the presently disclosed embodiments are illustrative in all respects and are not limiting. The embodiments can be modified and improved in various ways without departing from the spirit and scope of the appended claims. The matters described in the above-described embodiments can be configured in other ways as long as they are not inconsistent, and can be combined as long as they are not inconsistent.

[0083] The substrate processing apparatus 1 and deposition state monitoring method of the present disclosure can be applied to various types of apparatuses, regardless of whether plasma is used in substrate processing, such as atomic layer deposition (ALD) apparatus, capacitively coupled plasma (CCP), inductively coupled plasma (ICP), radial line slot antenna (RLSA), electron cyclotron resonance plasma (ECR), and helicon wave plasma (HWP). [Explanation of symbols]

[0084] 1. Substrate processing equipment 10 Processing container 54 Turbomolecular Pump 543 Rotating Structure 549 Motor 101 First Mountain 102 First Valley 103 Second Mountain 104 Second Valley

Claims

1. 1. A method for monitoring a deposition state of deposits deposited inside a pump connected to a processing vessel of a substrate processing apparatus for processing substrates, comprising: the pump is connected to the processing vessel and evacuates an internal space of the processing vessel, thereby introducing the processing gas supplied to the internal space into the pump; The control unit that controls the pump (a) acquiring a current value of a motor that rotates a rotating structure of the pump; (b) supplying the processing gas into the processing vessel to generate an attenuated waveform in the time change of the current value; (c) acquiring peak current values ​​of a plurality of peaks constituting the decay waveform and bottom current values ​​of the same number of valleys as the plurality of peaks; (d) calculating an estimated convergence current value at which the decay waveform converges by averaging the acquired peak current values ​​of the peak portions and the acquired bottom current values ​​of the valley portions; (e) estimating the deposition state of the deposits inside the pump based on the estimated convergence current value. Method for monitoring deposition status.

2. In the step (c), a plurality of peak current values ​​of the peak portions and a plurality of bottom current values ​​of the valley portions immediately after the start of the decay waveform are extracted. The deposition state monitoring method according to claim 1 .

3. the step (d) is performed immediately after a set number of peak current values ​​of the peak portions and bottom current values ​​of the valley portions are acquired; The deposition state monitoring method according to claim 2 .

4. In the step (c), peak current values ​​of the two peak portions and bottom current values ​​of the two valley portions immediately after the start of the decay waveform are extracted. The deposition state monitoring method according to claim 3 .

5. In the step (c), the bottom current value of the valley portion adjacent to the peak portion from which the peak current value is obtained is obtained.

5. The deposition state monitoring method according to claim 1.

6. (f) determining whether maintenance of the pump is required based on the state of deposits estimated in (e); The deposition state monitoring method according to any one of claims 1 to 4.

7. A substrate processing apparatus for processing a substrate, a processing vessel for processing the substrate; a pump connected to the processing vessel and configured to evacuate an internal space of the processing vessel; a control unit; The control unit (a) acquiring a current value of a motor that rotates a rotating structure of the pump; (b) supplying a processing gas into the processing vessel to generate an attenuated waveform in the time change of the current value; (c) acquiring peak current values ​​of a plurality of peaks constituting the decay waveform and bottom current values ​​of the same number of valleys as the plurality of peaks; (d) calculating an estimated convergence current value at which the decay waveform converges by averaging the acquired peak current values ​​of the peak portions and the acquired bottom current values ​​of the valley portions; (e) estimating a deposition state of deposits based on the estimated convergence current value. Substrate processing equipment.

Images