Substrate processing method and substrate processing equipment

Abstract

To stabilize a mixing ratio of mixed gas for use in processing of substrate.SOLUTION: A substrate processing apparatus implements a substrate processing method. The substrate processing apparatus includes a processing container, a supply line, an exhaust line, a vent line, and a flow rate controller. The supply line supplies mixed gas to an inside of the processing container. The exhaust line exhausts the mixed gas. The vent line connects the supply line and the exhaust line. The flow rate controller has a flow rate control valve and controls the flow rate of the mixed gas. A substrate processing method includes: a step (a) of supplying the mixed gas at a set flow rate to the vent line or the supply line; a step (b) of monitoring an opening degree of the flow rate adjustment valve; and a step (c) of adjusting the opening degree of the flow rate adjustment valve for use in processing of the substrate based on the monitored opening degree of the flow rate adjustment valve.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] For example, Patent Document 1 discloses that "a control signal is output so that a first step of determining the flow rate of the raw material in the raw material gas based on the flow rate of the carrier gas supplied from the carrier gas supply unit and the flow rate of the raw material gas detected by the flow rate detection unit, and acquiring the aperture of the flow rate control valve at which the flow rate of this raw material becomes a set value, and then a second step of cutting off the supply of the raw material gas by the raw material gas supply / cutoff unit in order to intermittently supply the raw material gas to the film formation processing unit with the aperture of the flow rate control valve fixed at the acquired aperture, and the above steps are performed every time a substrate to be processed is carried into the film formation processing unit."

[0003] For example, Patent Document 2 discloses "a first valve control unit that adjusts the opening of a first adjustment valve, a second adjustment valve provided in an inlet pipe, a flow meter that measures the flow rate of a carrier gas flowing through the inlet pipe or the flow rate of a mixed gas flowing through an outlet pipe, and in a first state in which the absolute value of the deviation between a measured concentration suggestion value and a set value is equal to or less than a predetermined value, the opening of the second adjustment valve is adjusted so that the measured flow rate measured by the flow meter becomes a predetermined reference value." [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6135475 [Patent Document 2] Patent No. 5615162 Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure provides a substrate processing method and a substrate processing apparatus that can stabilize the mixture ratio of a mixed gas used in processing a substrate. [Means for solving the problem]

[0006] In one aspect of the present disclosure, a substrate processing apparatus performs a substrate processing method. The substrate processing apparatus includes a processing vessel, a supply line, an exhaust line, a vent line, and a flow rate controller. The supply line supplies a mixed gas into the processing vessel. The exhaust line exhausts the mixed gas. The vent line connects the supply line and the exhaust line. The flow rate controller has a flow rate adjustment valve and controls the flow rate of the mixed gas. The substrate processing method includes (a) supplying the mixed gas at a set flow rate to the vent line or the supply line, (b) monitoring the aperture of the flow rate adjustment valve, and (c) adjusting the aperture of the flow rate adjustment valve used for processing the substrate based on the monitored aperture of the flow rate adjustment valve. [Effects of the Invention]

[0007] According to the present disclosure, the mixture ratio of the mixed gas used in substrate processing can be stabilized. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of a substrate processing apparatus according to an embodiment. [Figure 2] FIG. 2 is a schematic diagram of a flow rate controller according to one embodiment. [Figure 3] FIG. 3 is a diagram showing an example of a correlation graph between the flow rate of the mixed gas and the opening degree of the flow rate adjustment valve. [Figure 4A] FIG. 4A is a schematic diagram of an experimental system for supplying a mixed gas. [Figure 4B] FIG. 4B is a diagram showing an example of the flow rate of gas flowing through the experimental system. [Figure 4C] FIG. 4C is a diagram showing an example of a correlation graph between the gas flow rate and the opening degree of the flow rate adjustment valve. [Figure 5]FIG. 5 is a diagram showing an example of a correlation graph between the opening degree of the flow rate adjusting valve and the film thickness. [Figure 6] FIG. 6 is a flowchart showing a substrate processing method according to an embodiment. [Figure 7] FIG. 7 is a schematic view of a substrate processing apparatus according to an embodiment. [Figure 8A] FIG. 8A is a diagram showing an example of a film formation rate. [Figure 8B] FIG. 8B is a diagram showing an example of the opening degree of the flow rate adjusting valve during film formation. DETAILED DESCRIPTION OF THE INVENTION

[0009] The following describes in detail embodiments of the disclosed substrate processing method and substrate processing apparatus with reference to the drawings. Note that the substrate processing method and substrate processing apparatus according to the present disclosure are not limited to these embodiments, and the following embodiments can be appropriately combined within the scope of the present disclosure, so long as they do not cause any contradiction between the configurations and processing contents.

[0010] The drawings referred to below are schematic diagrams for the convenience of explanation, and therefore some details may be omitted and the dimensional proportions may not necessarily correspond to those of the actual objects.

[0011] [Substrate processing equipment] First, a configuration of a substrate processing apparatus according to an embodiment of the present disclosure will be described with reference to Fig. 1. Fig. 1 is a schematic diagram of the substrate processing apparatus according to the embodiment.

[0012] The substrate processing apparatus 10 performs processing such as film formation on the substrate W. For example, the substrate processing apparatus 10 performs a film formation process for an organic film such as polyurea, polyimide, polyamide, or polyurethane by vapor deposition polymerization. The substrate W may be a semiconductor wafer or a glass substrate. Film formation may be performed using a chemical vapor deposition (CVD) method, atomic layer deposition (ALD) method, or other film formation methods. The substrate processing apparatus 10 may be a single-wafer type substrate processing apparatus or a batch type substrate processing apparatus.

[0013] The substrate processing apparatus 10 includes a processing vessel 1, a gas supply unit 2, an exhaust system 3, and a control unit 4. The substrate processing apparatus 10 also includes a substrate support unit 11. The substrate support unit 11 is disposed within the processing vessel 1. The substrate support unit 11 supports a substrate W. The processing vessel 1 includes a processing space 12 defined by the ceiling wall, side walls, and substrate support unit 11 of the processing vessel 1. The processing vessel 1 is made of a conductor such as aluminum and is grounded.

[0014] The processing vessel 1 has at least one gas supply port 12d for supplying gas to the processing space 12 and at least one gas exhaust port 12e for exhausting gas from the plasma processing space. A gas supply unit 2 is connected to the gas supply port 12d. An exhaust system 3 is connected to the gas exhaust port. An opening (not shown) is formed in the sidewall of the processing vessel 1 for loading and unloading a substrate W into and from the processing vessel 1. The opening is opened and closed by a gate valve (not shown).

[0015] The gas supply unit 2 has a supply line 23. The exhaust system 3 has an exhaust line 31. The supply line 23 is configured to supply a mixed gas containing two or more types of gases into the processing chamber 1. The exhaust line 31 is configured to exhaust the mixed gas. The vent line 24 connects the supply line 23 and the exhaust line 31.

[0016] The gas supply unit 2 has a first gas supply unit 2a and a second gas supply unit 2b. The first gas supply unit 2a has a first supply line 23a. The second gas supply unit 2b has a second supply line 23b.

[0017] The supply line 23 is connected to a gas supply port 12d provided in the processing chamber 1. The supply line 23 includes a first supply line 23a and a second supply line 23b. The first supply line 23a is configured to supply a first mixed gas obtained by mixing two or more types of gases. The second supply line 23b is configured to supply a second mixed gas obtained by mixing two or more types of gases.

[0018] The vent line 24 includes a first vent line 24a and a second vent line 24b. The first vent line 24a connects the first supply line 23a to the exhaust line 31. The second vent line 24b connects the second supply line 23b to the exhaust line 31.

[0019] The exhaust line 31 is connected to a gas exhaust port 12e provided in the processing chamber 1. The exhaust system 3 further includes an exhaust device 32. The exhaust line 31 is connected to the exhaust device 32 and configured to exhaust the gas by the exhaust device 32. The exhaust device 32 may include a pressure regulating valve and a vacuum pump. The pressure regulating valve adjusts the pressure in the processing space 12s. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0020] The first gas supply unit 2a further includes a first vaporizer 40a, a first flow rate controller 50a, a first on-off valve 60a, and a third on-off valve 61a. A first supply line 23a connects the first vaporizer 40a and the processing chamber 1. The first supply line 23a is provided with the first vaporizer 40a, the first flow rate controller 50a, and the first on-off valve 60a, in this order from upstream to downstream. The first gas supply unit 2a supplies the first mixed gas output from the first vaporizer 40a into the processing chamber 1. For example, the first mixed gas may be a mixed gas of the first raw material LA and N2 gas. The N2 gas in the first mixed gas is an example of a carrier gas. The carrier gas is not limited to this, and may be an inert gas such as He gas.

[0021] The first vent line 24a branches off from the first supply line 23a between the first flow rate controller 50a and the first on-off valve 60a. The first vent line 24a is provided with a third on-off valve 61a and a first orifice 62a. The first on-off valve 60a controls the supply and stop of the first mixed gas from the first supply line 23a to the processing chamber 1. The third on-off valve 61a controls the exhaust and stop of the first mixed gas from the first vent line 24a to the exhaust line 31. The first orifice 62a is a throttle portion that adjusts the flow rate of the gas flowing through the first vent line 24a.

[0022] The second gas supply unit 2b includes a second vaporizer 40b, a second flow rate controller 50b, a second on-off valve 60b, and a fourth on-off valve 61b. A second supply line 23b connects the second vaporizer 40b to the processing chamber 1. The second supply line 23b is provided with, in order from upstream to downstream, the second vaporizer 40b, the second flow rate controller 50b, and the second on-off valve 60b. The second gas supply unit 2b supplies the second mixed gas output from the second vaporizer 40b into the processing chamber 1. For example, the second mixed gas may be a mixed gas of the second raw material LB and N2 gas. The N2 gas in the second mixed gas is an example of a carrier gas. The carrier gas is not limited to this, and may be an inert gas such as He gas.

[0023] The second vent line 24b branches off from the second supply line 23b between the second flow rate controller 50b and the second on-off valve 60b. The second vent line 24b is provided with a fourth on-off valve 61b and a second orifice 62b. The second on-off valve 60b controls the supply and stop of the second mixed gas from the second supply line 23b to the processing chamber 1. The fourth on-off valve 61b controls the exhaust and stop of the second mixed gas from the second vent line 24b to the exhaust line 31. The second orifice 62b is a throttle portion that adjusts the flow rate of the gas flowing through the second vent line 24b.

[0024] The second supply line 23b is connected to the first supply line 23a downstream of the first open / close valve 60a. However, the second supply line 23b may be connected to a gas supply port (not shown) formed in the processing chamber 1 without being connected to the first supply line 23a.

[0025] The distance D between the connection position D1 of the first vent line 24a and the exhaust line 31 and the connection position D2 of the second vent line 24b and the exhaust line 31 is several tens of centimeters or more. This makes it possible to prevent the first mixed gas discharged from the first vent line 24a to the exhaust line 31 and the second mixed gas discharged from the second vent line 24b to the exhaust line 31 from mixing in the exhaust line 31 and forming a film inside the pipe.

[0026] The first carrier gas source 21a is connected to a first carrier gas supply line 22a. The first carrier gas source 21a supplies N2 gas to the first vaporizer 40a. The second carrier gas source 21b is connected to a second carrier gas supply line 22b. The second carrier gas source 21b supplies N2 gas to the second vaporizer 40b. The first carrier gas supply line 22a and the second carrier gas supply line 22b are collectively referred to as carrier gas supply lines 22.

[0027] The first vaporizer 40a and the second vaporizer 40b are examples of vaporizers configured to vaporize a raw material and generate a gas containing the vaporized raw material gas. The first vaporizer 40a and the second vaporizer 40b are also collectively referred to as vaporizer 40.

[0028] The first vaporizer 40a has a tank 41a that stores the liquid first raw material LA. N2 gas flows through a first carrier gas supply line 22a and is supplied to the tank 41a. The first vaporizer 40a vaporizes the first raw material LA by heating, and generates a first mixed gas consisting of the vaporized first raw material gas and N2 gas as a carrier gas. The first raw material LA is not limited to a liquid, and may also be a solid. In the example of FIG. 1, the first mixed gas is indicated as Gas A.

[0029] The second vaporizer 40b has a tank 41b that stores the liquid second raw material LB. N2 gas flows through a second carrier gas supply line 22b and is supplied to the tank 41b. The second vaporizer 40b vaporizes the second raw material LB by heating, generating a second mixed gas consisting of the vaporized second raw material gas and N2 gas as a carrier gas. Note that the second raw material LB is not limited to a liquid, and may also be a solid. In the example of FIG. 1, the second mixed gas is indicated as Gas B.

[0030] The first flow rate controller 50a and the second flow rate controller 50b are mass flow controllers (MFCs), each having a flow rate adjustment valve and configured to monitor and control the gas flow rate and the current position of the flow rate adjustment valve. Specifically, the first flow rate controller 50a has a first flow rate adjustment valve and monitors and controls the flow rate of the first mixed gas and the current position of the first flow rate adjustment valve. The second flow rate controller 50b has a second flow rate adjustment valve and monitors and controls the flow rate of the second mixed gas and the current position of the second flow rate adjustment valve. The first flow rate controller 50a and the second flow rate controller 50b are also collectively referred to as flow rate controllers 50. The gas flow rates and the current positions of the flow rate adjustment valves monitored and controlled by the flow rate controller 50 are transmitted to the control unit 4 as log information of the flow rate controller 50 and stored in the memory of the control unit 4. The internal configuration of the flow rate controller 50 will be described later.

[0031] The control unit 4 processes computer-executable instructions that cause the substrate processing apparatus 10 to perform various processes included in the substrate processing method described in this disclosure. The control unit 4 may be configured to control each element of the substrate processing apparatus 10 to perform the various processes described herein. In one embodiment, part or all of the control unit 4 may be included in the substrate processing apparatus 10. The control unit 4 may include a processing unit, a storage unit, and a communication interface. The control unit 4 may be implemented, for example, by a computer. The processing unit may be configured to perform various control operations by reading a program from the storage unit and executing the read program. This program may be stored in the storage unit in advance or may be acquired via a medium when needed. The acquired program is stored in the storage unit and read from the storage unit by the processing unit for execution. The medium may be various computer-readable storage media or a communication line connected to the communication interface. The processing unit may be a central processing unit (CPU). The storage unit may include a random access memory (RAM), a read-only memory (ROM), a hard disk drive (HDD), a solid state drive (SSD), or a combination thereof. The communication interface communicates with the substrate processing apparatus 10 via a communication line such as a LAN (Local Area Network).

[0032] The first source material LA and the second source material LB are examples of monomers of film-forming materials. The first source material LA is an example of a first monomer and may be, for example, isocyanate. The first flow rate controller 50a controls the flow rate of a first mixed gas, which is a mixed gas of the first source material LA gas vaporized by the first vaporizer 40a and N2 gas. The second source material LB is an example of a second monomer and may be, for example, an amine. The second flow rate controller 50b controls the flow rate of a second mixed gas, which is a mixed gas of the second source material LB gas vaporized by the second vaporizer 40b and N2 gas.

[0033] The first source gas such as isocyanate and the second source gas such as amine are examples of film formation gases. For example, a first mixed gas containing isocyanate gas and a second mixed gas containing amine gas are mixed in the processing space 12 to form an organic film of a polymer having a urea bond on the surface of the substrate W supported by the substrate support 11.

[0034] For example, a linear polyurea can be produced by using a diisocyanate as the first monomer and a diamine (e.g., a primary amine) as the second monomer. A combination of a diisocyanate and a diamine is, for example, 4,4'-diphenylmethane diisocyanate (MDI) and 1,12-diaminododecane (DAD). A combination of a diisocyanate and a diamine is, for example, 1,3-bis(isocyanatomethyl)cyclohexane (H6XDI) and 1,12-diaminododecane (DAD). A combination of a diisocyanate and a diamine is, for example, 1,3-bis(isocyanatomethyl)cyclohexane (H6XDI) and 1,3-bis(aminomethyl)cyclohexane (H6XDA). Examples of the combination of diisocyanate and diamine include 1,3-bis(isocyanatomethyl)cyclohexane (H6XDI) and hexamethylenediamine (HMDA). Examples of the combination of diisocyanate and diamine include m-xylylenediisocyanate (XDI) and m-xylylenediamine (XDA). Examples of the combination of diisocyanate and diamine include m-xylylenediisocyanate (XDI) and benzylamine (BA).

[0035] For example, a crosslinkable polyurea can be produced by using a diisocyanate as the first monomer and a triamine (e.g., a primary amine) or tetraamine (e.g., a secondary amine) as the second monomer. A trimer having a urea bond can be produced by using a monoisocyanate as the first monomer and a diamine (e.g., a primary amine) as the second monomer. A dimer having a urea bond can be produced by using a monoisocyanate as the first monomer and a monoamine (e.g., a primary amine) as the second monomer.

[0036] [Flow Controller] Next, the internal configuration of the flow rate controller 50 will be described with reference to FIG. 2. FIG. 2 is a schematic diagram of the flow rate controller 50 according to one embodiment. The flow rate controller 50 includes a main flow path 52, a branch flow path 53, a bridge circuit 56, and an amplifier circuit 57. The inlet and outlet of the branch flow path 53 are connected to the main flow path 52. Resistors 54 and 55 are wound around the upstream and downstream pipe walls of the branch flow path 53. The bridge circuit 56 detects temperature changes in the pipe wall of the branch flow path 53 due to gas flow through the branch flow path 53 as changes in the resistance values ​​of the resistors 54 and 55, converts the detected temperature changes into gas flow rate signals, and outputs the signals. The amplifier circuit 57 amplifies the gas flow rate signals and transmits them to the control unit 4. The control unit 4 receives the gas flow rate signals and measures the gas flow rate controlled by the flow rate controller 50 based on the detected temperature changes.

[0037] The main flow path 52 is connected to the curved flow path 51 downstream of the branch position of the branch flow path 53. The flow rate controller 50 has a flow rate adjustment valve 58 that adjusts the flow rate of gas flowing through the curved flow path 51. The current position of the flow rate adjustment valve 58 is controlled by adjusting the stroke of the flow rate adjustment valve 58 using the control unit 4. This controls the flow rate of gas flowing through the curved flow path 51, in other words, the flow rate of gas output from the flow rate controller 50. The flow rate adjustment valve 58 is operated by an actuator 59. The actuator 59 has a stacked piezoelectric element 59a and a spring member 59b. A valve is provided at one end of the piezoelectric element 59a, and a spring member 59b is provided at the other end. The piezoelectric element 59a is fixed to the bottom of the flow rate adjustment valve 58 via the spring member 59b.

[0038] The control unit 4 monitors the flow rate signal and outputs a control signal to control the flow rate adjustment valve 58 based on the flow rate signal. The control unit 4 feedback-controls the control voltage value to be applied to the piezoelectric element 59a based on the control signal. This adjusts the stroke amount of the flow rate adjustment valve 58, i.e., the current position of the flow rate adjustment valve 58. In other words, this adjusts the opening degree of the flow rate adjustment valve 58. For example, the control unit 4 controls, in accordance with the control signal, what percentage of the maximum voltage that can be applied to the piezoelectric element 59a should be applied to the piezoelectric element 59a. This determines the current position of the flow rate adjustment valve 58, and adjusts the flow rate of the mixed gas flowing through the curved flow path 51. This allows the flow rate of the mixed gas supplied into the processing chamber 1 to be adjusted.

[0039] The control unit 4 controls the first flow rate controller 50a to control the control voltage applied to the piezoelectric element 59a so that the total flow rate of the first source gas and N2 gas, i.e., the flow rate of the first mixed gas, becomes a set flow rate value. This controls the current position of the flow rate adjustment valve 58 of the first flow rate controller 50a. This allows the flow rate of the first mixed gas supplied into the processing vessel 1 to be adjusted. Furthermore, the control unit 4 controls the second flow rate controller 50b to control the control voltage applied to the piezoelectric element 59a so that the total flow rate of the second source gas and N2 gas, i.e., the flow rate of the second mixed gas, becomes a set flow rate value. This controls the current position of the flow rate adjustment valve 58 of the second flow rate controller 50b. This allows the flow rate of the second mixed gas supplied into the processing vessel 1 to be adjusted.

[0040] [Gas concentration] When the first monomer and the second monomer are low vapor pressure raw materials, the low vapor pressure raw materials are difficult to evaporate, so when forming a film using the low vapor pressure raw materials, a vaporizer 40 is used and a carrier gas such as N2 gas is flowed into the vaporizer 40. This ensures a stable supply of vaporized gas.

[0041] The mixed gas of the source gas and carrier gas vaporized by the vaporizer 40 is supplied to the processing chamber 1 while the flow rate is controlled to a constant value by the flow rate controller 50. However, fluctuations in the current position of the flow rate control valve 58 can change the mixture ratio of the source gas and the carrier gas, thereby changing the concentration of the source gas used for film formation. This results in fluctuations in the film formation rate and reduced stability. For example, if the mixture ratio of the carrier gas to the source gas is increased while the flow rate of the mixed gas supplied to the processing chamber 1 is controlled to a constant value, the current position of the flow rate control valve 58 fluctuates, thereby reducing the film formation rate. Below, Experiments 1 to 3 are described regarding the relationship between the current position of the flow rate control valve 58 and the flow rate ratio of the carrier gas, as well as the relationship between the current position of the flow rate control valve 58 and film formation. The current position of the flow rate control valve 58 indicates the opening degree of the flow rate control valve 58. Therefore, the current position of the flow rate control valve 58 is described below as the opening degree of the flow rate control valve 58.

[0042] [Experiment 1] In Experiment 1, film formation was performed using the substrate processing apparatus 10 after four days of idle time. In Experiment 1, the flow rate of the mixed gas of the source gas and N2 gas was controlled to a constant value by the flow rate controller 50, and the aperture of the flow rate control valve was measured while the flow rate ratio of N2 gas to the source gas was varied. The results of Experiment 1 will be described with reference to FIG. 3. FIG. 3 is a diagram showing an example of a correlation graph between the flow rate of the mixed gas and the aperture of the flow rate control valve.

[0043] 3, the horizontal axis represents the number of substrates on which a film was formed, the left vertical axis represents the opening of the flow control valve (MFC Position), and the right vertical axis represents the gas flow value (MFC Flow). Line a represents the flow value of the mixed gas controlled by the flow controller 50. Line b represents the opening of the flow control valve.

[0044] As a result of Experiment 1, as shown by line a with white circles (◯), the flow rate of the mixed gas was constant while depositing the first to fifteenth substrates. In contrast, as shown by line b with black circles (●), the aperture of the flow control valve was unstable while depositing the first to third substrates, but stabilized while depositing the fourth to fifteenth substrates. In other words, during the deposition of the 15 substrates, the flow rate of the mixed gas was stable under the control of flow controller 50, but the aperture of the flow control valve was unstable in the early stages of deposition.

[0045] [Experiment 2] In Experiment 2, the flow rate of the mixed gas of the source gas and N2 gas was kept constant, and the aperture of the flow control valve was measured when the flow rate of the N2 gas was increased. Experiment 2 will be described with reference to FIGS. 4A to 4C. FIG. 4A is a schematic diagram of an experimental system for supplying the mixed gas. FIG. 4B is a diagram showing an example of the flow rate of the gas flowing into the experimental system. FIG. 4C is a diagram showing an example of a correlation graph between the gas flow rate and the aperture of the flow control valve.

[0046] 4A, flow rate controller (MFCa) 50c is disposed in carrier gas supply line 22 connected to carrier gas source 21 and vaporizer 40, and controls the flow rate of N2 gas. Flow rate controller (MFCb) 50d is disposed in supply line 23 connected to vaporizer 40, and controls the flow rate of the mixed gas of the source gas and N2 gas.

[0047] 4B, the flow rate controller (MFCa) 50c increases the flow rate of N2 gas stepwise from 50 (sccm) to 80 (sccm) in Steps 1 to 5. The flow rate controller (MFCb) 50d controls the flow rate of the mixed gas of the source gas and N2 gas to 80 (sccm) in Steps 1 to 5.

[0048] The horizontal axis of the graph in Figure 4C represents time, the left vertical axis represents gas flow rate (MFC Flow), and the right vertical axis represents the opening of the flow control valve (MFC Position). Line c represents the flow rate of N2 gas controlled by flow rate controller (MFCa) 50c. Line d represents the flow rate of the mixed gas controlled by flow rate controller (MFCb) 50d.

[0049] Line e shows the aperture of the flow control valve of flow controller (MFCb) 50d. As a result of experiment 2, as shown by line e, the aperture of the flow control valve of flow controller (MFCb) 50d fluctuated as the N2 gas increased. This is because the pressure in supply line 23 on the primary side (upstream side) of flow controller (MFCb) 50d increased due to the increase in N2 gas supplied to vaporizer 40. As a result, the pressure difference between the primary side and secondary side (downstream side) of flow controller (MFCb) 50d increased, and the aperture of the flow control valve decreased accordingly.

[0050] [Experiment 3] In Experiment 3, the film thickness of a substrate formed using the substrate processing apparatus 10 after one or two days of idle time was measured under different measurement conditions to examine the correlation between the aperture of the flow control valve and the film thickness. Figure 5 shows an example of a correlation graph between the aperture of the flow control valve and the film thickness. Measurement condition 1 was used when the optical constant was fixed, and measurement condition 2 was used when the optical constant was variable, and the film thickness was measured under measurement conditions 1 and 2.

[0051] The horizontal axis of the graph in Figure 5 shows the flow control valve opening (MFC position) 100 seconds after the start of film formation, and the vertical axis shows the film thickness (thickness) under measurement conditions 1 and 2 100 seconds after the start of film formation. Point f, marked with a white circle (◯), shows the film thickness under measurement condition 1 relative to the flow control valve opening, and point g, marked with a black circle (●), shows the film thickness under measurement condition 2 relative to the flow control valve opening. In experiment 3, the film thickness under both measurement condition 1 (point f) and measurement condition 2 (point g) became thinner as the flow control valve opening became smaller.

[0052] From the results of Experiments 1 to 3, it was found that when forming a film on a substrate using the substrate processing apparatus 10 after an idle time of one or two days or more, even if the flow rate of the mixed gas is controlled to be constant, the opening of the flow control valve becomes unstable and small in the early stage of film formation. Furthermore, the smaller the opening of the flow control valve, the lower the film formation rate and the thinner the film thickness.

[0053] Therefore, an embodiment of the present disclosure proposes a substrate processing method that can control the flow rate of the mixed gas to a constant value during film formation and stabilize the mixture ratio of the source gas and the carrier gas.

[0054] [Substrate processing method] A substrate processing method according to an embodiment of the present disclosure will be described with reference to FIGS. 1, 6, and 7. FIG. 6 is a flowchart illustrating the substrate processing method according to one embodiment. FIGS. 1 and 7 are schematic diagrams of a substrate processing apparatus according to one embodiment. The substrate processing method is controlled by a controller 4 and performed by a substrate processing apparatus 10. Note that the substrate processing apparatus 10 is an example of a substrate processing apparatus that performs the substrate processing method according to the present disclosure, and is not limited thereto.

[0055] The gases used for film formation are a first mixed gas A of a first source gas and N2 gas, and a second mixed gas B of a second source gas and N2 gas. In the substrate processing method, before film formation begins, the same mixed gas as that used for film formation is supplied in advance to the vent line 24 or the supply line 23. Supplying the mixed gas to be used for film formation before film formation begins is also called "preflow." In the substrate processing method, film formation begins after the flow rate of the mixed gas and the aperture of the flow rate control valve 58 have been stabilized by preflow.

[0056] 6, the control unit 4 determines whether or not there is a substrate on which a film is to be formed in the substrate processing apparatus 10. If the control unit 4 determines that there is a substrate on which a film is to be formed, the process proceeds to step S11.

[0057] Next, in step S11, the control unit 4 determines whether a predetermined idle time has elapsed in the substrate processing apparatus 10. The idle time is a time during which film formation is not continuously performed in the substrate processing apparatus 10, and may be set to a time during which the amount of source gas vaporized by the vaporizer 40 fluctuates. The idle time may be set to, for example, one or two days or more. If the control unit 4 determines in step S11 that the idle time has not elapsed, the control unit 4 proceeds to step S17, where the first mixed gas A and the second mixed gas B are supplied into the processing chamber 1, and film formation on the substrate is started.

[0058] On the other hand, if the control unit 4 determines in step S11 that the idle time has elapsed, the process proceeds to step S12, where the control unit 4 supplies the first mixed gas A to the first vent line 24a (preflow) and the second mixed gas B to the second vent line 24b (preflow).

[0059] As shown in FIG. 1, the flow rate of first mixed gas A (Gas A) is adjusted to a set flow rate value by a first flow rate controller 50a. The flow rate of second mixed gas B (Gas B) is adjusted to a set flow rate value by a second flow rate controller 50b. In step S12, the control unit 4 stabilizes the flow rate of first mixed gas A at the set flow rate value by flowing first mixed gas A for a predetermined time. In step S12, the control unit 4 stabilizes the flow rate of second mixed gas B at the set flow rate value by flowing second mixed gas B for a predetermined time. Step S12 is an example of step (a).

[0060] At this time, as shown in FIG. 1, the control unit 4 closes the first and second on-off valves 60a and 60b and opens the third and fourth on-off valves 61a and 61b. The on-off valves shown in white indicate an open state, and the on-off valves shown in black indicate a closed state. In this state, the control unit 4 exhausts the first mixed gas A from the exhaust line 31 via the first vent line 24a and the second mixed gas B from the exhaust line 31 via the second vent line 24b. The first orifice 62a can make the conductance of the first mixed gas A on the first vent line 24a side and the process vessel 1 side equal or close to each other. This stabilizes the pressure in the first vaporizer 40a and the evaporation rate of the first source material LA.

[0061] Furthermore, the second orifice 62b can make the conductance of the second mixed gas B between the second vent line 24b side and the processing vessel 1 side equal or close to each other, thereby stabilizing the pressure in the second vaporizer 40b and the amount of vaporization of the second source material LB.

[0062] Alternatively, the control unit 4 may supply the first mixed gas A to the first supply line 23a and the second mixed gas B to the second vent line 24b while closing the third on-off valve 61a and the second on-off valve 60b and opening the first on-off valve 60a and the fourth on-off valve 61b. Alternatively, the control unit 4 may supply the second mixed gas B to the second supply line 23b and the first mixed gas A to the first vent line 24a while closing the first on-off valve 60a and the fourth on-off valve 61b and opening the third on-off valve 61a and the second on-off valve 60b. In this manner, one of the first mixed gas A and the second mixed gas B may be supplied to the processing vessel 1, and the other may be supplied to the vent line 24.

[0063] Next, in step S13, the control unit 4 monitors the opening degree of the flow rate adjustment valve 58 of the first flow rate controller 50a. The flow rate adjustment valve 58 of the first flow rate controller 50a will be referred to as the "first flow rate adjustment valve." Step S13 is an example of the process (b).

[0064] Next, in step S14, the control unit 4 determines whether the aperture of the first flow control valve has stabilized. As an example of a method for determining whether the aperture of the first flow control valve has stabilized, the control unit 4 may determine that the aperture of the first flow control valve has stabilized when the monitored aperture of the first flow control valve is equal to or greater than a predetermined first threshold value for the first flow control valve. For example, in the example of FIG. 3 , when 71%, at which the aperture of the flow control valve is stabilized, is preset as the first threshold value, the control unit 4 may determine that the aperture of the first flow control valve has stabilized when the aperture of the first flow control valve is 71% or greater. Alternatively, when 71%±3% is preset as the range of the first threshold value, the control unit 4 may determine that the aperture of the first flow control valve has stabilized when the aperture of the first flow control valve is 68% or greater.

[0065] As another example of a method for determining whether the aperture of the first flow control valve has stabilized, the aperture of the first flow control valve may be determined to have stabilized when the monitored fluctuation in the aperture of the first flow control valve is equal to or less than a preset second threshold value for the first flow control valve. For example, when the second threshold value is 2%, the aperture of the first flow control valve may be determined to have stabilized when the monitored fluctuation in the aperture of the first flow control valve before and after the second threshold value is 2% or less. The control unit 4 repeats steps S13 and S14 until it determines that the aperture of the first flow control valve has stabilized, and when it determines that the aperture of the first flow control valve has stabilized, proceeds to step S15.

[0066] Next, in step S15, the control unit 4 monitors the opening degree of the flow rate adjustment valve 58 of the second flow rate controller 50b. The flow rate adjustment valve 58 of the second flow rate controller 50b will be referred to as the "second flow rate adjustment valve." Step S15 is an example of the process (b).

[0067] Next, in step S16, the control unit 4 determines whether the aperture of the second flow control valve has stabilized. The method for determining whether the aperture of the second flow control valve has stabilized may be the same as the method for determining whether the aperture of the first flow control valve has stabilized. The first threshold value for the first flow control valve and the first threshold value for the second flow control valve may be the same value or different values. Furthermore, the second threshold value for the first flow control valve and the second threshold value for the second flow control valve may be the same value or different values.

[0068] The control unit 4 repeats steps S15 and S16 until it determines that the opening degree of the second flow rate adjustment valve has stabilized, and when it determines that the opening degree of the second flow rate adjustment valve has stabilized, it proceeds to step S17. Note that steps S13 to S16 (particularly S14 and S16) are an example of the process (c).

[0069] In step S17, the control unit 4 starts film formation on the substrate. Step S17 is an example of process (d). For example, as shown in FIG. 7, the control unit 4 opens the first on-off valve 60a and the second on-off valve 60b, and closes the third on-off valve 61a and the fourth on-off valve 61b.

[0070] In this state, the control unit 4 supplies a first mixed gas A through the first supply line 23a into the processing chamber 1. In addition, the control unit 4 supplies a second mixed gas B through the second supply line 23b into the processing chamber 1.

[0071] For example, the control unit 4 supplies a first mixed gas A containing isocyanate gas and N2 gas into the processing vessel 1. The control unit 4 also supplies a second mixed gas B containing amine gas and N2 gas into the processing vessel 1. The first mixed gas A and the second mixed gas B are mixed in the processing space 12, and an organic film of a polymer having a urea bond is formed on the surface of the substrate W. After the film formation, the control unit 4 terminates this process.

[0072] 6, the processes of steps S15 and S16 are performed after the processes of steps S13 and S14, but this is not limiting. For example, the processes of steps S15 and S16 may be performed before the processes of steps S13 and S14. The processes of steps S15 and S16 may be performed in parallel with the processes of steps S13 and S14.

[0073] According to the substrate processing method of this embodiment, the preflow performed before film formation stabilizes the flow rate of the mixed gas and the mixture ratio of the source gas and the carrier gas, thereby preventing fluctuations in the film formation rate after the start of film formation and improving the stability of film formation.

[0074] [Film formation results] The results of film formation using the substrate processing method described above will be described with reference to Figures 8A and 8B. Figure 8A is a diagram showing an example of a film formation rate. Figure 8B is a diagram showing an example of the opening degree of the flow rate adjustment valve during film formation.

[0075] 8A and 8B show an example of the results of film formation after preflowing first mixed gas A and second mixed gas B into first vent line 24a and second vent line 24b, and stabilizing the flow rates of the mixed gases, the aperture of the first flow control valve, and the aperture of the second flow control valve. The horizontal axis of FIG. 8A represents the number of substrates, and the vertical axis represents the film formation rate. As shown in FIG. 8A, the film formation rate was nearly constant during film formation on the first to eighth substrates.

[0076] 8B, the horizontal axis represents the number of substrates, and the vertical axis represents the opening degree of the flow control valve (MFC Position). As shown in FIG. 8B, during film formation on the first to eighth substrates, the opening degrees of the first flow control valve and the second flow control valve were both almost constant.

[0077] [effect] When forming a polymer film, a vaporizer 40 using N2 gas is used to supply a first mixed gas A, which is a mixture of a first source gas (e.g., a first monomer) and N2 gas, and a second mixed gas B, which is a mixture of a second source gas (e.g., a second monomer) and N2 gas, into a processing space 12. Conventionally, the mixture ratio of the source gases and N2 gas changes during film formation, resulting in fluctuations in the film formation rate and unstable film formation. In contrast, according to the substrate processing method, a preflow process is performed before film formation, supplying the first mixed gas A and the second mixed gas B. While stabilizing the flow rates of the first mixed gas A and the second mixed gas B, the apertures of the first flow control valve and the second flow control valve are monitored. The apertures of the first flow control valve and the second flow control valve are then adjusted to stabilize the apertures. This stabilizes the mixture ratio of the source gases and N2 gas in the first mixed gas A and the second mixed gas B during film formation, thereby stabilizing the film formation rate and improving film formation stability.

[0078] The above describes the embodiment. As described above, the substrate processing method in the embodiment includes steps (a), (b), and (c). In step (a), a mixed gas is supplied to a vent line or a supply line at a set flow rate. In step (b), the aperture of a flow control valve is monitored. In step (c), the aperture of the flow control valve used for processing the substrate is adjusted based on the monitored aperture of the flow control valve.

[0079] Moreover, the substrate processing apparatus 10 in this embodiment includes a processing chamber 1, a supply line 23, an exhaust line 31, a vent line 24, a flow rate controller 50, and a control unit 4. The supply line 23 supplies a mixed gas into the processing chamber 1. The exhaust line 31 exhausts the mixed gas. The vent line 24 connects the supply line 23 and the exhaust line 31. The flow rate controller 50 has a flow rate adjustment valve 58 and controls the flow rate of the mixed gas. The control unit 4 controls steps including (a), (b), and (c).

[0080] It should be noted that the disclosed embodiments are illustrative in all respects and should not be considered limiting. Indeed, the above-described embodiments may be embodied in various forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims.

[0081] For example, the gas supply unit 2 may be at least one of a first gas supply unit 2a and a second gas supply unit 2b. For example, the supply line 23 may be at least one of a first supply line 23a and a second supply line 23b. For example, the vent line 24 may be at least one of a first vent line 24a and a second vent line 24b.

[0082] Furthermore, the following supplementary notes are disclosed regarding the above-described embodiment. (Appendix 1) A processing vessel; a supply line configured to supply a mixed gas into the interior of the processing vessel; an exhaust line configured to exhaust the mixed gas; a vent line connecting the supply line and the exhaust line; a flow rate controller having a flow rate adjustment valve and configured to control a flow rate of the mixed gas, (a) supplying the mixed gas at a set flow rate to the vent line or the supply line; (b) monitoring the opening of the flow control valve; (c) adjusting the aperture of the flow rate control valve used for processing the substrate based on the monitored aperture of the flow rate control valve; A substrate processing method comprising: (Appendix 2) In (c), the opening degree of the flow control valve is adjusted to the opening degree when the monitored opening degree of the flow control valve is equal to or greater than a first threshold value, or to the opening degree when the monitored fluctuation in the opening degree of the flow control valve is equal to or less than a second threshold value. 2. The substrate processing method of claim 1. (Appendix 3) (d) adjusting the aperture of the flow rate control valve in (c), and then starting processing of the substrate. 3. The substrate processing method according to claim 1 or 2. (Appendix 4) a vaporizer connected to the supply line and configured to vaporize a source material and generate the mixed gas containing the vaporized source gas; In the step (a), the mixed gas is supplied and the pressure inside the vaporizer is stabilized by adjusting the conductance between the vent line and the supply line. 4. A substrate processing method according to any one of claims 1 to 3. (Appendix 5) In the step (b), a control voltage value for controlling an actuator that operates the flow rate adjustment valve is monitored; In the step (c), the opening degree of the flow rate adjusting valve is adjusted by controlling the control voltage value based on the monitored control voltage value. 5. A substrate processing method according to any one of claims 1 to 4. (Appendix 6) The supply line a first supply line configured to supply a first gas mixture; a second supply line configured to supply a second gas mixture; The vent line is a first vent line connecting the first supply line and the exhaust line; a second vent line connecting the second supply line and the exhaust line; The flow rate controller includes: a first flow controller having a first flow adjustment valve and configured to control the flow rate of the first mixed gas; a second flow controller having a second flow adjustment valve and configured to control the flow rate of the second mixed gas; In the step (a), the first mixed gas is supplied to the first vent line or the first supply line at a set flow rate, and the second mixed gas is supplied to the second vent line or the second supply line at a set flow rate; In the step (b), the opening degree of the first flow rate adjustment valve and the opening degree of the second flow rate adjustment valve are monitored; In (c), the aperture of the first flow control valve used to process the substrate is adjusted based on the monitored aperture of the first flow control valve, and the aperture of the second flow control valve used to process the substrate is adjusted based on the monitored aperture of the second flow control valve. 6. A substrate processing method according to any one of claims 1 to 5. (Appendix 7) A processing vessel; a supply line configured to supply a mixed gas into the interior of the processing vessel; an exhaust line configured to exhaust the mixed gas; a vent line connecting the supply line and the exhaust line; a flow rate controller having a flow rate adjustment valve and configured to control the flow rate of the mixed gas; a control unit, The control unit (a) supplying the mixed gas at a set flow rate to the vent line or the supply line; (b) monitoring the opening of the flow control valve; (c) adjusting the aperture of the flow rate control valve used for processing the substrate based on the monitored aperture of the flow rate control valve; A substrate processing apparatus that controls a process including: [Explanation of symbols]

[0083] 1: Processing container 2: Gas supply section 2a: First gas supply unit 2b: Second gas supply section 3: Exhaust system 4: Control section 10: Substrate processing equipment 11: Substrate support part 23: Supply line 23a: First supply line 23b: Second supply line 24: Vent line 24a: First vent line 24b: Second vent line 31: Exhaust line 40: Vaporizer 40a: First vaporizer 40b: Second vaporizer 50: Flow controller 50a: First flow rate controller 50b: 2nd flow controller 58: Flow control valve

Claims

1. A processing vessel; a supply line configured to supply a mixed gas into the interior of the processing vessel; an exhaust line configured to exhaust the mixed gas; a vent line connecting the supply line and the exhaust line; a flow rate controller having a flow rate adjustment valve and configured to control a flow rate of the mixed gas, (a) supplying the mixed gas at a set flow rate to the vent line or the supply line; (b) monitoring the opening of the flow control valve; (c) adjusting the opening degree of the flow rate control valve used for processing the substrate based on the monitored opening degree of the flow rate control valve; A substrate processing method comprising:

2. In (c), the opening degree of the flow control valve is adjusted to an opening degree when the monitored opening degree of the flow control valve is equal to or greater than a first threshold value, or to an opening degree when the monitored fluctuation in the opening degree of the flow control valve is equal to or less than a second threshold value. The substrate processing method according to claim 1 .

3. (d) adjusting the opening of the flow rate adjusting valve in (c), and then starting the processing of the substrate. The substrate processing method according to claim 1 .

4. a vaporizer connected to the supply line and configured to vaporize a source material and generate the mixed gas containing the vaporized source gas; In the step (a), the mixed gas is supplied and the pressure inside the vaporizer is stabilized by adjusting the conductance between the vent line and the supply line. The substrate processing method according to claim 1 .

5. In the step (b), a control voltage value for controlling an actuator that operates the flow rate adjusting valve is monitored; In the step (c), the opening degree of the flow rate adjusting valve is adjusted by controlling the control voltage value based on the monitored control voltage value. The substrate processing method according to claim 1 .

6. The supply line a first supply line configured to supply a first gas mixture; a second supply line configured to supply a second gas mixture; The vent line is a first vent line connecting the first supply line and the exhaust line; a second vent line connecting the second supply line and the exhaust line; The flow rate controller includes: a first flow controller having a first flow adjustment valve and configured to control the flow rate of the first mixed gas; a second flow controller having a second flow adjustment valve and configured to control the flow rate of the second mixed gas; In the step (a), the first mixed gas is supplied to the first vent line or the first supply line at a set flow rate, and the second mixed gas is supplied to the second vent line or the second supply line at a set flow rate; In the step (b), the opening degree of the first flow rate adjustment valve and the opening degree of the second flow rate adjustment valve are monitored; In (c), the aperture of the first flow control valve used to process the substrate is adjusted based on the monitored aperture of the first flow control valve, and the aperture of the second flow control valve used to process the substrate is adjusted based on the monitored aperture of the second flow control valve. The substrate processing method according to any one of claims 1 to 5.

7. A processing vessel; a supply line configured to supply a mixed gas into the interior of the processing vessel; an exhaust line configured to exhaust the mixed gas; a vent line connecting the supply line and the exhaust line; a flow rate controller having a flow rate adjustment valve and configured to control the flow rate of the mixed gas; a control unit, The control unit (a) supplying the mixed gas at a set flow rate to the vent line or the supply line; (b) monitoring the opening of the flow control valve; (c) adjusting the opening degree of the flow rate control valve used for processing the substrate based on the monitored opening degree of the flow rate control valve; A substrate processing apparatus that controls a process including:

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