Substrate processing method and substrate processing apparatus

Abstract

A substrate processing method for processing a substrate by supplying a gas from a gas supply unit to a substrate processing space in a substrate processing apparatus, the gas supply unit comprising: a plurality of gas sources; a flow path through which the gas flows from the plurality of gas sources to the substrate processing space; a substrate processing method includes a substrate processing apparatus including a flow path configured to receive a gas, and a valve provided in the flow path and configured to switch a flow of the gas between a flow and a disconnection, in which pulse control is executed to pulse the flow of the gas by alternately repeating the flow of the gas between the flow and the disconnection in the valve, and in the pulse control, the flow of the gas between the flow and the disconnection of the gas is controlled by the valve to be switched between the flow and the disconnection of the gas. The flow rate of the gas is controlled by controlling the duration of the pulse control and the number of circulation times of the gas during the duration.

Description

Technical Field

[0001] The present disclosure relates to a substrate processing method and a substrate processing device. Background Art

[0002] Patent Document 1 discloses a method for switching and supplying two or more process gases in a semiconductor substrate etching apparatus. In the gas supply method, a path for supplying gas to a substrate processing space and a path for exhausting gas using an exhaust system are switched by opening and closing a valve, thereby pulsing the gas supply.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-144249 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] The technology disclosed herein can reduce gas waste during substrate processing and simplify a substrate processing apparatus.

[0008] Solutions for solving problems

[0009] One embodiment of the present disclosure is a substrate processing method for processing a substrate by supplying gas from a gas supply unit to a substrate processing space in a substrate processing device, wherein the gas supply unit comprises: a plurality of gas sources; a flow path for allowing the gas to flow from the plurality of gas sources to the substrate processing space; and a valve provided in the flow path for switching the flow of the gas between flow and disconnection. In the substrate processing method, pulse control is performed by pulse-controlling the flow of the gas by alternately repeating the flow of the gas between flow and disconnection in the valve. In the pulse control, the flow rate of the gas is controlled by controlling the duration of the pulse control and the number of times the gas flows during the duration.

[0010] Effects of the Invention

[0011] According to the present disclosure, it is possible to reduce gas waste during substrate processing and simplify a substrate processing apparatus. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is an explanatory diagram showing a configuration example of a plasma processing system according to an embodiment.

[0013] Figure 2 It is a cross-sectional view showing a structural example of a plasma processing apparatus according to one embodiment.

[0014] Figure 3 It is a plan view showing a structural example of an upper side baffle according to one embodiment.

[0015] Figure 4 It is a plan view showing a structural example of a lower side baffle according to one embodiment.

[0016] Figure 5 It is a plan view showing an example of arrangement of the upper baffle plate and the lower baffle plate.

[0017] Figure 6 It is a side view showing an example of the flow of gas in the exhaust gas via the upper baffle plate and the lower baffle plate.

[0018] Figure 7 It is an explanatory diagram showing a configuration example of a plasma processing system according to an embodiment.

[0019] Figure 8 It is an explanatory diagram showing an overview of pulse control in a substrate processing method according to an embodiment.

[0020] Fig. 9 This is a flowchart showing an overview of a substrate processing method according to one embodiment.

[0021] Fig.10 It is an explanatory diagram showing an overview of pulse control in a substrate processing method according to another embodiment.

[0022] Fig.11 This is a flowchart showing an overview of a substrate processing method according to another embodiment.

[0023] Fig.12 This is a schematic diagram showing an overview of a conventional gas supply system.

[0024] Fig.13 This is a diagram showing an overview of valve opening and closing control when gas is supplied using a conventional gas supply system. DETAILED DESCRIPTION

[0025] In the manufacturing process of semiconductor devices, a substrate processing space containing a semiconductor wafer (hereinafter referred to as a "substrate") is placed in a decompressed state to perform various processing steps for performing predetermined processing on the substrate. Gas processing is performed in these processing steps.

[0026] In the semiconductor dry process as the above-mentioned prescribed process performed by the substrate processing device, two or more process gases are sometimes repeatedly switched at high speed. For example, Patent Document 1 discloses a method of switching between a path for supplying gas to a substrate processing space and a path for discarding gas using an exhaust system by exclusively controlling a valve. Specifically, a method such as Fig.12 A gas supply system as exemplified above.

[0027] Fig.12 This is a schematic diagram showing an overview of a conventional gas supply system capable of switching between two or more gases using the method disclosed in Patent Document 1. The conventional gas supply system includes a gas box BR for supplying a mixed gas (GR) and a gas box BL for supplying another mixed gas (GL). The gas boxes BR and BL are connected to flow paths CR and CL, respectively. Flow paths CR and CL are provided with flow controllers FCR and FCL, respectively. Flow path CR is branched into an exhaust flow path ER connected to an exhaust system ES and a supply flow path SR connected to a substrate processing space PS. Flow path CL is branched into an exhaust flow path EL connected to the exhaust system and a supply flow path SL connected to the substrate processing space PS. The exhaust flow paths ER and EL are provided with exhaust valves VER and VEL, respectively, and the supply flow paths SR and SL are provided with supply valves VSR and VSL, respectively.

[0028] Fig.13 It is shown that the use Fig.12 The figure shows an overview of the opening and closing control of the valve when the conventional gas supply system supplies gas. In the conventional gas supply system, when supplying one mixed gas (GR) and other mixed gases (GL) alternately, when supplying one mixed gas GR, the exhaust valve VER and the supply valve VSL are closed, and the supply valve VSR and the exhaust valve VEL are opened. Thus, one mixed gas GR is supplied to the substrate processing space PS, and the other mixed gases GL are discarded through the exhaust system ES. In addition, when supplying other mixed gases GL, the exhaust valve VEL and the supply valve VSR are closed, and the supply valve VSL and the exhaust valve VER are opened. Thus, other mixed gases GL are supplied to the substrate processing space PS, and one mixed gas GR is discarded by the exhaust system ES. By repeating this action alternately, one mixed gas (GR) and other mixed gases (GL) are alternately supplied to the substrate processing space PS.

[0029] In addition, when the flow rate is changed by the flow controllers FCR and FCL, it takes time until the flow rate stabilizes. Specifically, a response time of about 500ms is required until the flow rate stabilizes. This is slow and impractical for the case of assuming a high-speed process. In view of this, in the gas supply system of patent document 1, the switching time is shortened by switching the mixed gas without changing the flow rate. According to such a gas switching mechanism, although the switching time can be shortened, the gas that is not supplied to the substrate processing space PS must be regularly discarded, resulting in a waste problem. In addition, in order to make the flow rate of the gas supplied to the substrate processing space PS the desired flow rate, the flow controllers FCR and FCL arranged downstream of the gas boxes BR and BL are necessary for the reasons described later. Therefore, there is a problem that the overall size of the gas supply system has to be increased by an amount corresponding to the flow controller. In addition, the "size of the system" includes the structural complexity of the system in addition to the simple occupied area (volume).

[0030] Therefore, the technology disclosed herein uses a valve capable of pulse control to perform gas supply, thereby eliminating the need for constant gas disposal during gas switching, thereby minimizing gas disposal. In addition, in conventional gas supply systems, it is not necessary to set a flow controller required for each gas downstream of the gas box, thereby simplifying the gas supply unit and, in turn, the substrate processing device. In addition, "simplifying" the gas supply unit and the substrate processing device includes relatively reducing the occupied area (volume) and / or simplifying the structure compared to the prior art.

[0031] Hereinafter, the structure of the substrate processing system according to the present embodiment will be described with reference to the drawings. In addition, in this specification, the same reference numerals are given to elements having substantially the same functional structure to omit repeated description.

[0032] Figure 1 : is a diagram for illustrating a structural example of a plasma processing system. In one embodiment, the plasma processing system includes a plasma processing device 1 and a control unit 2. The plasma processing system is an example of a substrate processing system, and the plasma processing device 1 is an example of a substrate processing device. The plasma processing device 1 includes a plasma processing chamber 10, a substrate support portion 11, and a plasma generating portion 12. The plasma processing chamber 10 has a substrate processing space 10s. In addition, the plasma processing chamber 10 has at least one gas supply port for supplying at least one processing gas to the substrate processing space 10s, and at least one gas exhaust port for exhausting gas from the substrate processing space 10s. The gas supply port is connected to the gas supply portion 20 described later, and the gas exhaust port is connected to the exhaust system 40 described later. The substrate support portion 11 is arranged in the substrate processing space 10s, and has a substrate supporting surface for supporting a substrate.

[0033] The plasma generating unit 12 is configured to generate plasma from at least one processing gas supplied into the substrate processing space 10s. The plasma formed in the substrate processing space 10s may be a capacitively coupled plasma (CCP: Capacitively Coupled Plasma), an inductively coupled plasma (ICP: Inductively Coupled Plasma), an ECR plasma (Electron-Cyclotron-Resonance Plasma: Electron Cyclotron Resonance Plasma), a helicon wave excited plasma (HWP: Helicon Wave Plasma) or a surface wave plasma (SWP: Surface Wave Plasma), etc. In addition, various types of plasma generating units including an AC (Alternating Current: Alternating Current) plasma generating unit and a DC (Direct Current: Direct Current) plasma generating unit may also be used. In one embodiment, the AC signal (AC power) used in the AC plasma generating unit has a frequency in the range of 100kHz to 10GHz. Therefore, the AC signal includes an RF (Radio Frequency: Radio Frequency) signal and a microwave signal. In one embodiment, the RF signal has a frequency in the range of 100kHz to 150MHz.

[0034] The control unit 2 processes computer executable commands that cause the plasma processing device 1 to execute various processes described in the present disclosure. The control unit 2 can be configured to control the various elements of the plasma processing device 1 to execute the various processes described herein. In one embodiment, a part or all of the control unit 2 can be included in the plasma processing device 1. The control unit 2 can include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The control unit 2 is implemented, for example, by a computer 2a. The processing unit 2a1 can be configured to perform various control actions by reading a program from the storage unit 2a2 and executing the read program. The program can be stored in the storage unit 2a2 in advance, or it can be obtained via a medium when necessary. The obtained program is stored in the storage unit 2a2, and is read and executed from the storage unit 2a2 by the processing unit 2a1. The medium can be various storage media that can be read by the computer 2a, or it can be a communication line connected to the communication interface 2a3. The processing unit 2a1 can be a CPU (Central Processing Unit). The storage unit 2a2 may include a RAM (Random Access Memory), a ROM (Read Only Memory), a HDD (Hard Disk Drive), an SSD (Solid State Drive), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing device 1 via a communication line such as a LAN (Local Area Network).

[0035] Next, a configuration example of a capacitive coupling type plasma processing apparatus 1 as an example of a substrate processing apparatus will be described. Figure 2 It is a diagram for explaining a configuration example of a capacitive coupling type plasma processing apparatus 1 .

[0036] A capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply 30, and an exhaust system 40. In addition, the plasma processing apparatus 1 includes a substrate support unit 11 and a gas inlet unit. The gas inlet unit is configured to introduce at least one processing gas into the plasma processing chamber 10. The gas inlet unit includes a shower head 13. The substrate support unit 11 is disposed in the plasma processing chamber 10. The shower head 13 is disposed above the substrate support unit 11. In one embodiment, the shower head 13 constitutes at least a portion of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a substrate processing space 10s defined by the shower head 13, the side wall 10a of the plasma processing chamber 10, and the substrate support unit 11. The plasma processing chamber 10 is grounded. The shower head 13 and the substrate support unit 11 are electrically insulated from the shell of the plasma processing chamber 10.

[0037] The substrate support portion 11 includes a main body 111 and a ring assembly 112. The main body 111 has a central area 111a for supporting a substrate W and an annular area 111b for supporting the ring assembly 112. The annular area 111b of the main body 111 surrounds the central area 111a of the main body 111 when viewed from above. The substrate W is arranged on the central area 111a of the main body 111, and the ring assembly 112 is arranged on the annular area 111b of the main body 111 in a manner of surrounding the substrate W on the central area 111a of the main body 111. Therefore, the central area 111a is also referred to as a substrate supporting surface for supporting the substrate W, and the annular area 111b is also referred to as a ring supporting surface for supporting the ring assembly 112.

[0038] In one embodiment, the main body 111 includes a base 1110 and an electrostatic holding disk (holding disk: chuck) 1111. The base 1110 includes a conductive component. The conductive component of the base 1110 can function as a lower electrode. The electrostatic holding disk 1111 is arranged on the base 1110. The electrostatic holding disk 1111 includes a ceramic component 1111a and an electrostatic electrode 1111b arranged in the ceramic component 1111a. The ceramic component 1111a has a central area 111a. In one embodiment, the ceramic component 1111a also has an annular area 111b. In addition, other components surrounding the electrostatic holding disk 1111, such as an annular electrostatic holding disk or an annular insulating component, may also have an annular area 111b. In this case, the ring assembly 112 can be arranged on the annular electrostatic holding disk or the annular insulating component, or on both the electrostatic holding disk 1111 and the annular insulating component. In addition, at least one RF / DC electrode coupled to the RF power supply 31 and / or the DC power supply 32 described later may be arranged in the ceramic component 1111a. In this case, the at least one RF / DC electrode functions as a lower electrode. In the case where the bias RF signal and / or the DC signal described later are supplied to the at least one RF / DC electrode, the RF / DC electrode is also referred to as a bias electrode. In addition, the conductive component of the base 1110 and the at least one RF / DC electrode may also function as a plurality of lower electrodes. In addition, the electrostatic electrode 1111b may also function as a lower electrode. Thus, the substrate support portion 11 includes at least one lower electrode.

[0039] The ring assembly 112 includes one or more ring-shaped members. In one embodiment, the one or more ring-shaped members include one or more edge rings and at least one cover ring. The edge ring is formed of a conductive material or an insulating material, and the cover ring is formed of an insulating material.

[0040] In addition, the substrate support 11 may include a temperature control module, which is configured to adjust at least one of the electrostatic holding disk 1111, the ring assembly 112 and the substrate W to a target temperature. The temperature control module may include a heater, a heat transfer medium, a flow path 1110a or a combination thereof. A heat transfer fluid such as brine or gas flows in the flow path 1110a. In one embodiment, the flow path 1110a is formed in the base 1110, and one or more heaters are arranged in the ceramic component 1111a of the electrostatic holding disk 1111. In addition, the substrate support 11 may include a heat transfer gas supply unit, which is configured to supply a heat transfer gas to the gap between the back side of the substrate W and the central area 111a.

[0041] The shower head 13 is configured to introduce at least one processing gas from the gas supply unit 20 into the substrate processing space 10s. The shower head 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and a plurality of gas introduction ports 13c. The processing gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the substrate processing space 10s from the plurality of gas introduction ports 13c. In addition, the shower head 13 includes at least one upper electrode. In addition, the gas introduction unit may include, in addition to the shower head 13, one or more side gas injection units (SGI: Side Gas Injector) installed in one or more openings formed in the side wall 10a.

[0042] The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one processing gas from the corresponding gas source 21 to the shower head 13 via the corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. In addition, the gas supply unit 20 may include at least one flow modulation device that modulates or pulses the flow of at least one processing gas. In this specification, the gas source is recorded as the upstream side of the gas flow, and the substrate processing space 10s is recorded as the downstream side. The details of the gas supply unit 20 and the substrate processing space 10s are described later.

[0043] The power supply 30 includes an RF power supply 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply 31 is configured to supply at least one RF signal (RF power) to at least one lower electrode and / or at least one upper electrode. Thus, plasma is formed from at least one processing gas supplied to the substrate processing space 10s. Therefore, the RF power supply 31 can function as at least a part of the plasma generating unit 12. In addition, by supplying a bias RF signal to at least one lower electrode, a bias potential can be generated on the substrate W to attract ion components in the formed plasma to the substrate W.

[0044] In one embodiment, the RF power supply 31 includes a first RF generating unit 31a and a second RF generating unit 31b. The first RF generating unit 31a is configured to be coupled to at least one lower electrode and / or at least one upper electrode via at least one impedance matching circuit to generate a source RF signal (source RF power) for generating plasma. In one embodiment, the source RF signal has a frequency in the range of 10 MHz to 150 MHz. In one embodiment, the first RF generating unit 31a may also be configured to generate a plurality of source RF signals having different frequencies. The generated one or more source RF signals are supplied to at least one lower electrode and / or at least one upper electrode.

[0045] The second RF generating unit 31b is configured to be coupled to at least one lower electrode via at least one impedance matching circuit to generate a bias RF signal (bias RF power). The frequency of the bias RF signal may be the same as or different from the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency lower than the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 100kHz to 60MHz. In one embodiment, the second RF generating unit 31b may also be configured to generate a plurality of bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to at least one lower electrode. In addition, in various embodiments, at least one of the source RF signal and the bias RF signal may also be pulsed.

[0046] In addition, the power supply 30 may include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generating unit 32a and a second DC generating unit 32b. In one embodiment, the first DC generating unit 32a is configured to be connected to at least one lower electrode and generate a first DC signal. The generated first DC signal is applied to at least one lower electrode. In one embodiment, the second DC generating unit 32b is configured to be connected to at least one upper electrode and generate a second DC signal. The generated second DC signal is applied to at least one upper electrode.

[0047] In various embodiments, the first DC signal and the second DC signal may also be pulsed. In this case, a sequence of voltage pulses is applied to at least one lower electrode and / or at least one upper electrode. The voltage pulse may have a rectangular, trapezoidal, triangular, or a pulse waveform of a combination of these shapes. In one embodiment, a waveform generator for generating a sequence of voltage pulses from a DC signal is connected between the first DC generator 32a and at least one lower electrode. Thus, the first DC generator 32a and the waveform generator constitute a voltage pulse generator. In the case where the second DC generator 32b and the waveform generator constitute a voltage pulse generator, the voltage pulse generator is connected to at least one upper electrode. The voltage pulse may have a positive polarity or a negative polarity. In addition, the sequence of voltage pulses may include one or more positive polarity voltage pulses and one or more negative polarity voltage pulses in one cycle. In addition, a first DC generator 32a and a second DC generator 32b may be provided in addition to the RF power supply 31, or a first DC generator 32a may be provided instead of the second RF generator 31b.

[0048] The exhaust system 40 can be connected to, for example, a gas exhaust port 10e disposed at the bottom of the plasma processing chamber 10. The exhaust system 40 can include a pressure regulating valve and a vacuum pump. The pressure in the substrate processing space 10s is adjusted by the pressure regulating valve. The vacuum pump can include a turbomolecular pump, a dry pump, or a combination thereof.

[0049] In one embodiment, the exhaust system 40 includes an upper baffle plate 41 and a lower baffle plate 42. The upper baffle plate 41 and the lower baffle plate 42 are respectively provided with through holes 43 and 44. The upper baffle plate 41 and the lower baffle plate 42 form a boundary between the substrate processing space 10s and the exhaust system 40.

[0050] Figure 3 1 is a top view of the upper baffle plate 41 as viewed from the top side of the plasma processing chamber 10. As shown in the figure, the upper baffle plate 41 has a through hole 43 in addition to the plate portion indicated by the hatching. The through hole 43 allows gas to flow, and specifically, the gas flows from the substrate processing space 10s to the exhaust system 40 through the through hole 43.

[0051] Figure 4 1 is a top view of the lower baffle plate 42 as viewed from the top side of the plasma processing chamber 10. As shown in the figure, the lower baffle plate 42 has a through hole 44 in addition to the plate portion indicated by the hatching. The through hole 44 allows gas to flow, and specifically, gas flows from the substrate processing space 10s to the exhaust system 40 through the through hole 44.

[0052] Figure 5This is a top view of the upper baffle 41 and the lower baffle 42 viewed from the top side in order to show the arrangement relationship between the upper baffle 41 and the lower baffle 42. As shown in the figure, the upper baffle 41 and the lower baffle 42 are arranged in such a manner that the positions of their through holes 43 and 44 are staggered. In the example in the figure, the plate portion of the upper baffle 41 indicated by the shadow overlaps with the through hole 44 of the lower baffle 42, and the plate portion of the lower baffle 42 indicated by the shadow overlaps with the through hole 43 of the upper baffle 41.

[0053] Figure 6 This is a side view of the upper baffle plate 41 and the lower baffle plate 42 as viewed from the chamber side wall 10a. Figure 6 The flow of gas is indicated by a bold arrow. In addition, the thickness of the bold arrow indicates the relative size of the flow of gas. At least one of the upper baffle 41 and the lower baffle 42 moves in the up-down direction. When the upper baffle 41 and the lower baffle 42 are close to each other, the distance between the through holes 43 and 44 becomes shorter, thereby suppressing the flow of gas flowing through the through holes 43 and 44. In addition, in addition to the above-mentioned structure, at least one of the upper baffle 41 and the lower baffle 42 rotates, and the distance between the through holes 43 and 44 changes, thereby changing the flow of gas. According to this structure, by using the upper baffle 41 and the lower baffle 42, the volume of the substrate processing space 10s can be limited, and even when the exhaust speed is increased, the exhaust can be performed while keeping the pressure in the substrate processing space 10s uniform.

[0054] Next, use Figure 7 The gas supply unit 20 and the substrate processing space 10s according to the present embodiment will be described in detail. Figure 7 1 is a schematic diagram schematically showing the gas supply unit 20 , the substrate processing space 10 s , and a flow path connecting the gas supply unit 20 and the substrate processing space 10 s according to the present embodiment.

[0055] exist Figure 7In the embodiment, the gas supply unit 20 includes gas boxes 200a, 200b and a flow path. The gas box 200a includes gas sources 21a, 21b, 21c and a plurality of flow controllers 22a, 22b, 22c corresponding to these gas boxes, respectively. In addition, the gas box 200b includes gas sources 21d, 21e, 21f and a plurality of flow controllers 22d, 22e, 22f corresponding to these gas sources, respectively. The flow path includes a plurality of first flow paths 204a, 204b and a second flow path 206. The downstream sides of the plurality of gas sources 21a to 21f are connected to the upstream sides of the corresponding plurality of flow controllers 22a to 22f, respectively. In addition, the downstream sides of the plurality of flow controllers 22a to 22f are connected to the first flow paths 204a and 204b, respectively. The downstream of the first flow paths 204a and 204b merges with the second flow path 206. The downstream of the second flow path 206 is connected to the substrate processing space 10s. The downstream of the second flow path 206 can be connected to the gas inlet and connected to the substrate processing space 10s via the above-mentioned shower head 13. In addition, the gas box 200 is not limited to the structure shown in the figure. For example, it can also be configured to supply the mixed gas to one of the first flow paths 204a and 204b from a gas box having a gas source that supplies a mixed gas in which a plurality of gas species are mixed in a desired ratio. In addition, the combination or number of the gas source 21, the flow controller 22 and the first flow paths 204a and 204b is not limited to the structure shown in the figure. For example, the number of multiple flow controllers 22 and the corresponding gas sources 21 that merge with one of the first flow paths 204a and 204b can be increased and decreased to the desired number. In addition, for example, it can also be set to a structure that can be switched in a manner that allows the desired combination of multiple gas sources 21 to merge, and control to mix in a desired ratio in one of the first flow paths 204a and 204b.

[0056] In one embodiment, buffer tanks 210a and 210b are provided in the first flow paths 204a and 204b, respectively. The buffer tanks 210a and 210b have pressure sensors P1 and P2, respectively, which can measure the pressure inside them. The buffer tanks 210a and 210b can be configured so that the area of ​​the cross section (hereinafter referred to as the flow path cross section) perpendicular to the flow path direction of the gas (hereinafter referred to as the flow path cross section) is larger than the flow path cross section area of ​​the pipe constituting the first flow paths 204a and 204b. In this case, the flow path cross section area of ​​the buffer tanks 210a and 210b can be set to an area of ​​more than 3 times the flow path cross section area of ​​the first flow paths 204a and 204b. In addition, in this case, the length of the buffer tanks 210a and 210b in the flow path direction can be set to a length equal to or greater than the diameter of the flow path cross section of the buffer tanks 210a and 210b.

[0057] In one embodiment, the volume of the buffer tank 210a is configured to be sufficiently larger than the target value (volume value) of the supply amount of the mixed gas Gα in the step ST12 related to one pulse group described later, and the volume of the buffer tank 210b is configured to be sufficiently larger than the target value (volume value) of the supply amount of the mixed gas Gβ in the step ST16 related to one pulse group described later. In this case, the volumes of the buffer tanks 210a and 210b are preferably 5 times or more, and more preferably 10 times or more, of the target values ​​of the supply amounts of the mixed gases Gα and Gβ, respectively.

[0058] In another embodiment, the volume of the buffer tanks 210a and 210b is variable. For example, a piston is provided, and the piston can be controlled to change the volume of the buffer tanks 210a and 210b to a desired volume.

[0059] In another embodiment, the buffer tanks 210a and 210b are configured to have variable temperatures. For example, a temperature control mechanism is connected, and the temperature control mechanism can be controlled to change the gas inside the buffer tanks 210a and 210b to a desired temperature. In this case, the temperature control mechanism can be a heater that heats the gas inside the buffer tanks 210a and 210b.

[0060] Pulse valves 220a and 220b are provided in the first flow paths 204a and 204b. In addition, throttle holes 222a and 222b are provided downstream of the pulse valves 220a and 220b. Pulse valves 220a and 220b can use pulse valves that can be switched between open and closed instantly. Specifically, it is preferred to use a valve that can switch the flow of gas between flow and disconnection in a manner that the pulse interval is less than 50ms at least, but there is no special limitation. If it is the above-mentioned speed, the gas can be supplied at a flow rate and switching speed with sufficient accuracy in the flow control performed using the pulse valves 220a and 220b described later. In addition, in this specification, the control of alternatingly repeating the flow and disconnection in the pulse valves 220a and 220b is recorded as pulse control. In addition, the flow of gas once in the pulse control from setting the pulse valves 220a and 220b to setting them to an open state and then to a closed state again is recorded as one pulse PL.

[0061] A chamber monitor 224 is provided on the chamber sidewall 10a as a detection unit capable of detecting plasma luminescence or gas composition in the substrate processing space 10s. The chamber monitor 224 may be, for example, an optical emission spectrometer (OES) capable of detecting plasma luminescence in the substrate processing space 10s from the chamber sidewall 10a. In addition, the chamber monitor 224 may also be a known detection device capable of detecting gas composition in the substrate processing space 10s from the chamber sidewall 10a. In one embodiment, the chamber monitor 224 sends information on the detected plasma luminescence (including luminescence amount or luminescence intensity ratio) or gas composition (including the amount or ratio of gas, and the gas includes products generated due to deviation of gas composition) to the control unit 2. The control unit 2 performs calculations based on the information, updates the target value of the gas supply amount, and sends the target value to the controller 226. The controller 226 controls the pulse valves 220a and 220b based on the target value to increase and decrease the flow rate in the pulse valves 220a and 220b.

[0062] In addition, Figure 7 In the embodiment, as a preferred structure, buffer tanks 210a and 210b are provided, but this structure is not essential, and buffer tanks 210a and 210b may not be provided. In this case, for example, a portion of the piping constituting the first flow paths 204a and 204b may be extended to have the same size as the buffer tanks 210a and 210b. In addition, although the second flow path 206 is provided, this structure is not essential. In this case, the downstream of the first flow paths 204a and 204b may be directly connected to the gas inlet portion, such as the shower head 13. In addition, a chamber monitor 224 is provided, but this structure is not essential.

[0063] Next, use Figure 8 to Figure 11 A substrate processing method according to this embodiment will be described. Figure 8 It is an explanatory diagram of the opening and closing control of the pulse valve in the substrate processing method MT1 according to one embodiment. Fig. 9 It is a flowchart showing an outline of a substrate processing method MT1 according to one embodiment. Fig.10 It is an explanatory diagram showing an outline of another example of pulse control in the substrate processing method MT1 according to one embodiment. Fig.11 1 is a flowchart showing an overview of a substrate processing method MT2 according to another embodiment. The substrate processing methods MT1 and MT2 according to the present embodiment can be performed in the above-mentioned plasma processing system, for example. In the substrate processing methods MT1 and MT2, the flow rate of the gas supplied to the substrate processing space 10s is controlled by pulse control of the pulse valves 220a and 220b.

[0064] In the following description of the substrate processing methods MT1 and MT2, the following case is described: Figure 7 In the plasma processing system shown, gas species a to c are supplied to the first flow path 204a from gas sources 21a to 21c via flow controllers 22a to 22c, and gas species d to f are supplied to the first flow path 204b from gas sources 21d to 21f via flow controllers 22d to 22f. In addition, the gas species a to f can be known gases used in processes such as etching or deposition, or known gases used to dilute these gases. Before executing the substrate processing methods MT1 and MT2, the gas species a to c are mixed in the first flow path 204a to form a mixed gas Gα, and are accumulated in the buffer tank 210a at a desired pressure. In addition, the gas species d to f are mixed in the first flow path 204b to form a mixed gas Gβ, and are accumulated in the buffer tank 210b at a desired pressure.

[0065] Next, a description will be given of a case where the gas supply is started and the mixed gas Gα and the mixed gas Gβ are supplied alternately and separately in the substrate processing method MT1 according to the present embodiment. Figure 8 and Fig. 9 In the process, first, pulse control is started in the pulse valve 220a provided on the first flow path 204a. In the pulse control, the following actions are repeatedly performed: the pulse valve 220a is changed from a closed state to an open state, and then to a closed state again. During this period, the pulse valve 220b is set to a closed state (process ST10). Thereafter, when the supply amount of the mixed gas Gα reaches the target value, the pulse control in the pulse valve 220a is terminated, and the supply of the mixed gas Gα is stopped (process ST12). Next, the same pulse control as above is performed in the pulse valve 220b provided on the first flow path 204b, during which the pulse valve 220a is set to a closed state (process ST14). Thereafter, when the supply amount of the mixed gas Gβ reaches the target value, the pulse control in the pulse valve 220b is terminated, and the supply of the mixed gas Gβ is stopped (process ST16). Thereafter, the pulse control of the pulse valve 220a and the pulse valve 220b is repeated alternately until the desired process is completed (process ST18).

[0066] like Fig.10As shown, a delay time DT may be provided when the pulse control of the mixed gas Gα is ended and the control of the mixed gas Gβ is started, or vice versa (hereinafter, these two times are collectively referred to as the switching of the mixed gas). That is, for example, it may be provided that after the pulse control of the mixed gas Gα is ended, the control of the mixed gas Gβ is started after the delay time DT. When the mixed gas is switched, the gas in the first flow path 204a, 204b, the second flow path 206 and the substrate processing space 10s on the downstream side of the pulse valves 220a, 220b is exhausted. Therefore, the delay time DT is set to the time until the exhaust is completed. Specifically, it is preferred to set the delay time DT to 10ms to 1s.

[0067] The target value of the supply amount of the mixed gas may be read in as a target value predetermined for each process. The control unit 2 may send a start command and an end command to the controller 226 based on the target value, and the controller 226 starts and ends the pulse control by controlling the pulse valves 220a and 220b.

[0068] The pulse control will be described in more detail. The duration of the pulse control and the number of pulses PL during the duration can be determined based on the flow rate of each pulse PL and the target value of the supply amount of the mixed gas. Specifically, first, the number of pulses is determined in such a way that the product of the flow rate of each pulse PL and the number of pulses becomes the target value of the supply amount. For example, if the target value of the supply amount in the process is 100, and the flow rate of the mixed gas of each pulse PL is 1, setting the number of pulses to 100 times can supply 100 supply amounts. After determining the number of pulses, the duration of the pulse control can be determined in such a way that the pulse control can be performed at the desired pulse intervals. In addition, the flow rate in a pulse PL can also be set to be pre-determined under process conditions.

[0069] When switching the mixed gas, in addition to switching to the supply of the mixed gas of the other party at the time when the supply amount of the mixed gas of one party reaches the target value as described above, the method MT2 described below can also be adopted. That is, the state in the substrate processing space 10s is monitored by the chamber monitor 224, and the supply of the mixed gas is started or ended based on the monitoring result. Specifically, the state in the substrate processing space 10s is monitored by using the chamber monitor 224 such as OES to detect the ratio, amplitude, wavelength correlation, etc. of the luminous wavelength of the plasma luminescence of the gas. In this case, first, these detection results detected by the chamber monitor 224 are sent to the control unit 2. Then, in the control unit 2, it is determined based on the detection results whether the process α based on the mixed gas Gα is completed, or whether the process β based on the mixed gas Gβ is completed. When it is determined that the process α or the process β is completed, an instruction is sent to the controller 226 to control the pulse valves 220a, 220b to perform the switching of the mixed gas.

[0070] exist Fig.11In the embodiment of the present invention, as an example of monitoring the gas state in the substrate processing space 10s as described above, the monitoring using OES and the control of the pulse valves 220a and 220b based on the monitoring results are described. As an example, consider the case where the mixed gas Gα currently supplied is an etching gas containing fluorine and the mixed gas Gβ currently disconnected is a deposition gas. First, the pulse valve 220a is pulse-controlled to supply the mixed gas Gα (process ST20). At this time, by supplying the mixed gas Gα, a plasma of the etching gas is formed in the substrate processing space 10s, so that the etching of the substrate W as the object to be processed progresses. During the etching process, the fluorine in the mixed gas Gα is consumed by etching, so the plasma luminescence amount of fluorine is low. On the other hand, when the etching is nearly completed, the fluorine in the mixed gas Gα is no longer consumed by etching, and the amount present in the substrate processing space 10s increases. As a result, the plasma luminescence of fluorine increases, and the detection amount in the OES increases. That is, when the detection amount of the plasma luminescence generated by fluorine in the OES is detected to have increased, it can be judged that the etching is nearly completed (process ST22). In the present embodiment, when the plasma luminescence amount is less than the threshold value, the mixed gas Gα is continuously supplied, and when the plasma luminescence amount becomes greater than the threshold value, it is determined that etching is completed and the supply of the mixed gas Gα is stopped. In this way, it is possible to suppress the excessive supply of the mixed gas Gα into the substrate processing space 10s. Afterwards, the pulse valve 220a is closed, and the pulse valve 220a is pulse-controlled to execute the next process (process ST24). Regarding the process β based on the mixed gas Gβ, it is also monitored in the same way as above and it is determined whether the process β is completed (step ST26). When it is determined that the process β is completed, the pulse control of the pulse valve 220a is returned again or the process is ended (process ST28). Regarding the threshold value of the plasma luminescence amount, the luminescence amount of the wavelength that serves as an indicator of the progress of the process can be determined in advance in the process conditions and stored in the storage unit, and read in when the process is executed.

[0071] In addition, in the above, as the detection object, the plasma luminescence amount of fluorine in the etching gas is detected, but it is not limited to this. It can also be set to judge the progress of the process by detecting the amount of gas present, gas ratio, etc. that is an indicator of the progress of the process. The gas detected here includes products generated by the deviation of the gas component in addition to the gas component itself. In this case, it can be set that for each gas that becomes the indicator, a threshold is determined in advance under the process conditions and stored in the storage unit, and read when the process is executed. In addition, in the above, the plasma luminescence amount is monitored and compared with the threshold, but it is not limited to this. For example, the degree of progress of etching can be judged by monitoring the intensity ratio of multiple wavelengths of light detected by OES and comparing it with the threshold. In this case, the comparison with the threshold can be set as follows: when the intensity ratio is less than the threshold, the mixed gas Gα is continuously supplied, and when the intensity ratio becomes above the threshold, the mixed gas Gα is stopped. In addition, the comparison with the threshold can also be set as follows: when the intensity ratio becomes above the threshold, the mixed gas Gα is continuously supplied, and when the intensity ratio is less than the threshold, the mixed gas Gα is stopped. Regarding the threshold value of the intensity ratio, the intensity ratio of light of a wavelength serving as an indicator of the progress of the process may be determined in advance under process conditions and stored in a storage unit, and read in when the process is executed.

[0072] In addition, the above description describes an example of pulse control and switching control for two gases, the mixed gas Gα and the mixed gas Gβ, but the same control can be performed when three or more mixed gases flow through three or more first flow paths and are supplied to the substrate processing space 10s. In this case, during the pulse control involving one mixed gas, the pulse valve involved in the flow of other mixed gases can be closed to stop the supply. In addition, a delay time DT can also be set between the switching of each mixed gas.

[0073] Next, the significance of the plasma processing apparatus 1 and the substrate processing methods MT1 and MT2 configured as described above in the present disclosure will be described in detail.

[0074] As in Fig.12As described in , in the previous method, regarding the structure and method of switching two or more gases, the switching time is shortened by switching between the path supplied to the substrate processing space PS and the path exhausted by the exhaust system ES. In the previous structure, in addition to the cost problem of continuously discarding the gas that is not supplied to the substrate processing space PS, there is also the following problem. That is, in the previous structure, when supplying one gas, the supply valves VSR and VSL remain in an open state. In this state, the flow rate of the gas supplied through the supply valves VSR and VSL depends on the specifications of the supply valves VSR and VSL and is limited to a certain value. Therefore, in order to make the supplied gas the desired flow rate, flow controllers FCR and FCL must be set on the flow paths CR and CL. In contrast, in the technology involved in the present disclosure, the gas to be supplied is supplied by pulse control using pulse valves 220a and 220b. Instead of supplying the gas in the state where the valve is open, the gas is supplied by pulse control, which has the following meaning. That is, by changing the density, number, interval, and duration of pulse PL to desired values, the gas to be supplied can be controlled to a desired flow value. That is, according to the pulse control of the present disclosure, the flow rate of the gas supplied to the substrate processing space 10s can be controlled to a desired value. That is, in the gas supply unit 20 of the present disclosure, it is not necessary to set a flow controller for each mixed gas. As a result, the system size of the gas supply unit can be made smaller than in the previous structure.

[0075] Next, the significance of the buffer tanks 210a and 210b and the orifices 222a and 222b provided as a preferred structure in the present disclosure will be described.

[0076] According to the pulse control using the pulse valves 220a and 220b, the flow rate of the circulating gas is not constant, and sometimes changes periodically depending on the conditions of the pulse control. In this specification, such a periodic change in flow rate is referred to as flow pulsation. Flow pulsation occurs not only downstream of the pulse valves 220a and 220b, but may also occur upstream.

[0077] It is believed that when flow pulsation occurs, loads are generated on structural components, and various sensors such as pressure sensors are unstable in measurement. It is known that the extent of this influence caused by flow pulsation depends on the volume of the space where the flow pulsation occurs, that is, the flow path. Specifically, the smaller the volume of the flow path, the greater the above-mentioned influence of the flow pulsation, and the larger the volume of the flow path, the smaller the above-mentioned influence of the flow pulsation. Therefore, in one embodiment of the present disclosure, it is configured to provide buffer tanks 210a and 210b. That is, the buffer tanks 210a and 210b have the function of buffering the flow pulsation by expanding the volume of the space where the flow pulsation occurs. In addition, the throttle holes 222a and 222b have the function of making the flow rate uniform downstream thereof. By means of the buffer tanks 210a and 210b, the size of the flow pulsation can be reduced, and the above-mentioned influence can be fully suppressed. In order to further exert this effect, as a preferred structure of the buffer tanks 210a and 210b, the flow path cross-sectional area is set to an area 3 times or more than the flow path cross-sectional area of ​​the first flow path 204a and 204b, and the length of the buffer tanks 210a and 210b in the flow path direction is set to a length equal to or more than the diameter of the flow path cross section of the buffer tanks 210a and 210b. On the other hand, when the volume of the buffer tanks 210a and 210b is too large, the time required to make the buffer tanks 210a and 210b reach the desired pressure by filling with gas becomes longer. In addition, at the end of the process, the piping including the buffer tanks 210a and 210b is exhausted, so a corresponding amount of gas will be wasted. Therefore, it is not preferred that the buffer tanks 210a and 210b are unnecessarily large.

[0078] After in-depth research, the inventors of the present invention found that when a buffer tank is provided, during the process of executing pulse control, the pressure in the buffer tank does not change from the start of supplying the mixed gas to the end of the supply when the supply amount of the mixed gas reaches the target value, and remains roughly constant, which is important for more precise control of the gas supply amount.

[0079] In the following description, a series of pulse controls from the start of supplying the mixed gas to the end of supplying the mixed gas when the supply amount reaches the target value is referred to as a pulse group. A series of controls from starting the pulse control of the pulse valve 220a in step ST10 to closing the pulse valve 220a in step ST14 is an example of a pulse group.

[0080] If the mixed gas supplied in the present disclosure is regarded as an ideal gas, and the pressure in the buffer tank is set to P, the volume of the buffer tank is set to V, the supply amount (mass) of the mixed gas in a pulse group is set to n, the gas constant is set to R, and the absolute temperature of the mixed gas is set to T, then according to the state equation of the gas, P=nRT / V holds.

[0081] From this point of view, as described above, in one embodiment, the volume of the buffer tank is configured to be sufficiently larger than the target value (volume value) of the supply amount of the mixed gas in one pulse group. When the gas in the pulse group is supplied, the mixed gas in the buffer tank is reduced by a maximum amount corresponding to the supply amount n of the mixed gas. At this time, the volume V of the buffer tank is large enough relative to the gas volume reduced from the buffer tank (that is, a function of the supply amount n), so that the pressure P in the buffer tank can be fixed. In addition, the pressure P is fixed including not less than a desired threshold value described later.

[0082] In another embodiment, the volume of the buffer tank is variable. When the gas is supplied in the pulse group, the mixed gas in the buffer tank is reduced by a maximum amount corresponding to the supply amount n of the mixed gas. At this time, by controlling the volume of the buffer tank to be reduced by an amount corresponding to the volume of the mixed gas reduced from the buffer tank, for example, the ratio n / V of the supply amount n to the volume V can be kept approximately constant, so that the pressure P in the buffer tank can be kept constant.

[0083] In another embodiment, the temperature of the buffer tank is variable. When the gas is supplied in the pulse group, the mixed gas in the buffer tank is reduced by a maximum amount corresponding to the supply amount n of the mixed gas. However, by increasing the absolute temperature T of the gas by an amount corresponding to the mixed gas reduced from the buffer tank at this time, for example, the product nT of the supply amount n and the absolute temperature T can be kept approximately constant, thereby making it possible to keep the pressure P in the buffer tank constant.

[0084] Here, it is more preferable that the pressure P in the buffer tank is kept substantially constant during the duration of the pulse control from the start to the end of one pulse group, but in one embodiment, the pressure P in the buffer tank may be reduced to a value greater than a desired threshold value. As an example, the threshold value is 80% of the value of the pressure P at the start of the pulse group.

[0085] In addition, Figure 7 In the embodiment, the buffer tanks 210a and 210b are arranged on the first flow paths 204a and 204b on the upstream side of the pulse valves 220a and 220b, but are not limited to this. For example, the first flow paths 204a and 204b may also be arranged on the downstream side of the pulse valves 220a and 220b. In this case, it also plays a role in reducing the influence of the above-mentioned flow pulsation. However, since the first flow paths 204a and 204b on the downstream side of the pulse valves 220a and 220b are exhausted when the mixed gas is switched, the exhaust time will be correspondingly longer when the buffer tanks 210a and 210b are large. From this point of view, the buffer tanks 210a and 210b are more preferably arranged on the first flow paths 204a and 204b on the upstream side of the pulse valves 220a and 220b.

[0086] Next, the significance of the chamber monitor 224 provided as a preferred configuration in the present disclosure will be described.

[0087] In processes such as deposition and etching, the required amount of deposition gas and etching gas depends on the condition of the substrate W as the process object and the condition of the device. Regarding the condition of the substrate W, for example, the surface area and surface properties of the substrate W can be cited. In addition, regarding the condition of the device, for example, the consumption of consumable parts, the amount of processing residues (deposits) in the chamber or inside the piping can be cited. Therefore, it is preferable to change the supply amount of gas according to the substrate condition and the condition of the device. According to the substrate processing method MT2, by using the chamber monitor 224 to monitor the state in the substrate processing space 10s, the switching of the mixed gas can be performed at the time when the process is actually completed.

[0088] Next, the significance of providing the delay time DT and the exhaust system 40 in the present disclosure as described above will be described.

[0089] When the mixed gas Gα and the mixed gas Gβ are supplied separately and alternately as described above, both the mixed gas Gα and the mixed gas Gβ flow through the second flow path 206 and the substrate processing space 10s downstream of the pulse valve 220a or the pulse valve 220b, so it is conceivable that these gases are mixed against their intention. In contrast, according to the delay time DT involved in this embodiment, it is possible to control so that the supply of the other mixed gas can be started at the time point when the supply of either the mixed gas Gα or the mixed gas Gβ is completed and the exhaust of the second flow path 206 and the substrate processing space 10s is completed.

[0090] From the perspective of productivity, it is preferred that the delay time DT described above is as short as possible without mixing of the mixed gas. In order to shorten the delay time DT, it is preferred that the exhaust speed of the substrate processing space 10s is sufficiently high. When performing such high-speed exhaust, it is preferred to improve the uniformity of the pressure in the space of the substrate processing space 10s and the exhaust system 40. As a specific example of such an exhaust system 40, it is preferred to use a system including Figure 2 to Figure 6 The structure of the upper baffle plate 41 and the lower baffle plate 42 is shown.

[0091] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The above-mentioned embodiments may be omitted, replaced, or changed in various ways without departing from the attached claims, the structural examples belonging to the technical scope of the present disclosure described later, and the gist thereof. For example, the constituent elements of the above-mentioned embodiments may be arbitrarily combined. According to the arbitrary combination, the functions and effects of the various constituent elements involved in the combination can be obtained, and other functions and effects that are clearly known to those skilled in the art based on the description of this specification can be obtained.

[0092] In addition, the effects described in this specification are merely explanatory or illustrative, and are not limiting. That is, the technology involved in this disclosure can also have other effects that are clearly known to those skilled in the art based on the description of this specification in addition to or instead of the above effects.

[0093] The following structures also belong to the technical scope of the present disclosure.

[0094] (1) A substrate processing method for processing a substrate by supplying gas from a gas supply unit to a substrate processing space in a substrate processing apparatus,

[0095] The gas supply unit includes: a plurality of gas sources; a flow path for allowing the gas to flow from the plurality of gas sources to the substrate processing space; and a valve disposed in the flow path for switching the flow of the gas between flow and disconnection.

[0096] In the substrate processing method, pulse control is performed to pulse the flow of the gas by alternately repeating the flow of the gas and shutting off the flow of the gas in the valve.

[0097] In the pulse control, the flow rate of the gas is controlled by controlling the duration of the pulse control and the number of times the gas is circulated during the duration.

[0098] (2) In the substrate processing method described in (1) above,

[0099] The flow path includes a plurality of first flow paths provided corresponding to the plurality of gas sources, and a second flow path formed by merging the plurality of first flow paths.

[0100] The valves are respectively provided in the plurality of first flow paths.

[0101] The pulse control is performed on the valve provided on one of the first flow paths to supply the gas to the substrate processing space, and the other valves provided on the other first flow paths are closed.

[0102] (3) In the substrate processing method described in (2) above,

[0103] Two or more of the gas sources among the plurality of gas sources correspond to one of the plurality of first flow paths,

[0104] The plurality of gases are supplied from the plurality of gas sources, respectively, and are mixed in the first flow path.

[0105] (4) In the substrate processing method described in (2) or (3) above, the method comprises:

[0106] performing said pulse control in one of said valves;

[0107] Thereafter, disconnecting the flow of the gas in the valve; and

[0108] After a delay time of 10 ms to 1 s has elapsed, the pulse control is performed in the other one of the valves.

[0109] (5) In the substrate processing method described in any one of (1) to (4) above,

[0110] The substrate processing device includes a detection unit configured to detect plasma light emission in the substrate processing space.

[0111] When the gas supplied to the substrate processing space through the pulse control is an etching gas, while the pulse control is continued, if the light emission of the plasma is less than a threshold value, the pulse control is continued, and when the light emission becomes greater than the threshold value, the pulse control is terminated.

[0112] (6) In the substrate processing method described in any one of (1) to (5) above,

[0113] The substrate processing apparatus includes a detection unit configured to detect gas components in the substrate processing space.

[0114] During the pulse control, when the amount of the component of the gas supplied to the substrate processing space by the pulse control is greater than a threshold, the pulse control is continued, and when the amount of the component of the gas is less than the threshold, the pulse control is terminated.

[0115] (7) In the substrate processing method described in (2) or (3) above,

[0116] The substrate processing apparatus includes a buffer tank on each of the plurality of first flow paths.

[0117] The flow path cross-sectional area of ​​the buffer tank is at least three times the flow path cross-sectional area of ​​the first flow path in which the buffer tank is provided.

[0118] The length of the buffer tank in the flow path direction is equal to or greater than the diameter of the flow path cross section of the buffer tank.

[0119] (8) In the substrate processing method described in any one of (1) to (7),

[0120] The substrate processing device comprises an upper electrode,

[0121] The gas is supplied from the gas supply unit to the vicinity of the center of the upper electrode, and the gas is diffused in a diffusion chamber provided in the upper electrode and supplied to the substrate processing space.

[0122] (9) A substrate processing apparatus comprising:

[0123] A processing chamber, wherein a substrate processing space is formed inside the processing chamber;

[0124] a gas supply unit for supplying gas to the substrate processing space; and

[0125] Control Department,

[0126] The gas supply unit includes: a plurality of gas sources; a flow path for allowing gas to flow from the plurality of gas sources to the substrate processing space; and a valve disposed in the flow path for switching the flow of the gas between flow and disconnection.

[0127] The control unit is configured to execute the following steps: when the gas is supplied from the gas supply unit to the substrate processing space to process the substrate, pulse control is performed to pulse the flow of the gas by alternately repeating the flow of the gas and disconnecting the flow of the gas in the valve,

[0128] In the pulse control, the flow rate of the gas is controlled by controlling the duration of the pulse control and the number of times the gas is circulated during the duration.

[0129] (10) In the substrate processing apparatus described in (9) above,

[0130] The flow path includes a plurality of first flow paths provided corresponding to the plurality of gas sources, and a second flow path formed by merging the plurality of first flow paths.

[0131] The valves are respectively provided in the plurality of first flow paths.

[0132] The control unit is further configured to execute the step of performing the pulse control on the valve provided on one of the first flow paths to supply the gas to the substrate processing space and closing the other valves provided on the other first flow paths.

[0133] (11) In the substrate processing apparatus described in (10) above,

[0134] Two or more of the gas sources among the plurality of gas sources correspond to one of the plurality of first flow paths,

[0135] The control unit is further configured to be capable of executing the step of supplying the plurality of gases from the plurality of gas sources, respectively, and mixing the plurality of gases in the first flow path.

[0136] (12) In the substrate processing apparatus described in (10) or (11),

[0137] The control unit is further configured to execute the following process, which includes:

[0138] performing said pulse control in one of said valves;

[0139] Thereafter, disconnecting the flow of the gas in the valve; and

[0140] After a delay time of 10 ms to 1 s has elapsed, the pulse control is performed in the other one of the valves.

[0141] (13) In the substrate processing apparatus described in any one of (9) to (12) above,

[0142] A detection unit is provided for detecting plasma light emission in the substrate processing space,

[0143] The control unit is also configured to be able to perform the following process: when the gas supplied to the substrate processing space through the pulse control is an etching gas, while the pulse control is continued, when the light emission of the plasma is less than a threshold value, the pulse control is continued, and when the light emission becomes greater than the threshold value, the pulse control is terminated.

[0144] (14) In the substrate processing apparatus described in any one of (9) to (13) above,

[0145] A detection unit is provided for detecting gas components in the substrate processing space.

[0146] The control unit is also configured to be able to execute the following process: while the pulse control is being continued, when the amount of the component of the gas supplied to the substrate processing space through the pulse control is greater than a threshold value, the pulse control is continued; when the amount of the component of the gas is less than the threshold value, the pulse control is terminated.

[0147] (15) In the substrate processing apparatus described in (10) or (11),

[0148] A buffer tank is provided on each of the plurality of first flow paths;

[0149] The flow path cross-sectional area of ​​the buffer tank is at least three times the flow path cross-sectional area of ​​the first flow path in which the buffer tank is provided.

[0150] The length of the buffer tank in the flow path direction is equal to or greater than the diameter of the flow path cross section of the buffer tank.

[0151] (16) In the substrate processing apparatus described in any one of (9) to (15) above,

[0152] having an upper electrode,

[0153] The control unit is further configured to execute the step of supplying the gas from the gas supply unit to the vicinity of the center of the upper electrode, diffusing the gas in a diffusion chamber provided in the upper electrode, and introducing the gas into the substrate processing space.

[0154] Description of Reference Numerals

[0155] 1: substrate processing apparatus; 10s: substrate processing space; 20: gas supply unit; 220a, 220b: pulse valves; W: substrate; PL: pulse.

Claims

1. A substrate processing method, for processing a substrate by supplying gas from a gas supply unit to a substrate processing space in a substrate processing device, The gas supply unit includes: a plurality of gas sources; a flow path for allowing the gas to flow from the plurality of gas sources to the substrate processing space; and a valve disposed in the flow path for switching the flow of the gas between flow and disconnection. In the substrate processing method, pulse control is performed to pulse the flow of the gas by alternately repeating the flow of the gas and shutting off the flow of the gas in the valve. In the pulse control, the flow rate of the gas is controlled by controlling the duration of the pulse control and the number of times the gas is circulated during the duration.

2. The substrate processing method according to claim 1, wherein: The flow path includes a plurality of first flow paths provided corresponding to the plurality of gas sources, and a second flow path formed by merging the plurality of first flow paths. The valves are respectively provided in the plurality of first flow paths. The pulse control is performed on the valve provided on one of the first flow paths to supply the gas to the substrate processing space, and the other valves provided on the other first flow paths are closed.

3. The substrate processing method according to claim 2, wherein: Two or more of the gas sources among the plurality of gas sources correspond to one of the plurality of first flow paths, The plurality of gases are supplied from the plurality of gas sources, respectively, and are mixed in the first flow path.

4. The substrate processing method according to claim 2 or 3, comprising: performing said pulse control in one of said valves; Thereafter, disconnecting the flow of the gas in the valve; as well as After a delay time of 10 ms to 1 s has elapsed, the pulse control is performed in the other one of the valves.

5. The substrate processing method according to any one of claims 1 to 3, wherein: The substrate processing device includes a detection unit that detects plasma light emission in the substrate processing space. When the gas supplied to the substrate processing space through the pulse control is an etching gas, while the pulse control is continued, if the light emission of the plasma is less than a threshold value, the pulse control is continued, and when the light emission becomes greater than the threshold value, the pulse control is terminated.

6. The substrate processing method according to any one of claims 1 to 3, wherein: The substrate processing apparatus includes a detection unit configured to detect gas components in the substrate processing space. During the pulse control, when the amount of the component of the gas supplied to the substrate processing space by the pulse control is greater than a threshold, the pulse control is continued, and when the amount of the component of the gas is less than the threshold, the pulse control is terminated.

7. The substrate processing method according to claim 2 or 3, wherein: The substrate processing apparatus includes a buffer tank on each of the plurality of first flow paths. The flow path cross-sectional area of ​​the buffer tank is at least three times the flow path cross-sectional area of ​​the first flow path in which the buffer tank is provided. The length of the buffer tank in the flow path direction is equal to or greater than the diameter of the flow path cross section of the buffer tank.

8. The substrate processing method according to claim 7, wherein: Regarding the buffer tank, a volume of the buffer tank is 5 times or more of a target value of the supply amount of the gas in one pulse group.

9. The substrate processing method according to claim 8, wherein: Regarding the buffer tank, a volume of the buffer tank is 10 times or more of a target value of the supply amount of the gas in one pulse group.

10. The substrate processing method according to claim 7, wherein: The buffer tank is configured so that a volume of the buffer tank is variable, and during the duration of the pulse control, the volume of the buffer tank is reduced so that a pressure of the buffer tank is constant.

11. The substrate processing method according to claim 7, wherein: The buffer tank is configured to be able to adjust the temperature of the gas in the buffer tank, and the temperature of the gas in the buffer tank is increased during the duration of the pulse control so that the pressure in the buffer tank is constant.

12. The substrate processing method according to any one of claims 1 to 3, wherein: The substrate processing device comprises an upper electrode, The gas is supplied from the gas supply unit to the vicinity of the center of the upper electrode, and the gas is diffused in a diffusion chamber provided in the upper electrode and introduced into the substrate processing space.

13. A substrate processing device comprising: A processing chamber, wherein a substrate processing space is formed inside the processing chamber; a gas supply unit for supplying gas to the substrate processing space; and Control Department, in, The gas supply unit includes: a plurality of gas sources; a flow path for allowing gas to flow from the plurality of gas sources to the substrate processing space; and a valve disposed in the flow path for switching the flow of the gas between flow and disconnection. The control unit is configured to execute the following steps: when the gas is supplied from the gas supply unit to the substrate processing space to process the substrate, pulse control is performed to pulse the flow of the gas by alternately repeating the flow of the gas and disconnecting the flow of the gas in the valve, In the pulse control, the flow rate of the gas is controlled by controlling the duration of the pulse control and the number of times the gas is circulated during the duration.

14. The substrate processing apparatus according to claim 13, wherein: The flow path includes a plurality of first flow paths provided corresponding to the plurality of gas sources, and a second flow path formed by merging the plurality of first flow paths. The valves are respectively provided in the plurality of first flow paths. The control unit is further configured to execute the step of performing the pulse control on the valve provided on one of the first flow paths to supply the gas to the substrate processing space and closing the other valves provided on the other first flow paths.

15. The substrate processing apparatus according to claim 14, wherein: Two or more of the gas sources among the plurality of gas sources correspond to one of the plurality of first flow paths, The control unit is further configured to be capable of executing the step of supplying the plurality of gases from the plurality of gas sources, respectively, and mixing the plurality of gases in the first flow path.

16. The substrate processing apparatus according to claim 13 or 14, wherein: The control unit is further configured to execute the following process, which includes: performing said pulse control in one of said valves; Thereafter, disconnecting the flow of the gas in the valve; and After a delay time of 10 ms to 1 s has elapsed, the pulse control is performed in the other one of the valves.

17. The substrate processing apparatus according to any one of claims 13 to 15, wherein: A detection unit is provided for detecting plasma light emission in the substrate processing space, The control unit is also configured to be able to perform the following process: when the gas supplied to the substrate processing space through the pulse control is an etching gas, while the pulse control is continued, when the light emission of the plasma is less than a threshold value, the pulse control is continued, and when the light emission becomes greater than the threshold value, the pulse control is terminated.

18. The substrate processing apparatus according to any one of claims 13 to 15, wherein: A detection unit is provided for detecting gas components in the substrate processing space. The control unit is also configured to be able to execute the following process: while the pulse control is being continued, when the amount of the component of the gas supplied to the substrate processing space through the pulse control is greater than a threshold value, the pulse control is continued; when the amount of the component of the gas is less than the threshold value, the pulse control is terminated.

19. The substrate processing apparatus according to claim 14 or 15, wherein: A buffer tank is provided on each of the plurality of first flow paths; The flow path cross-sectional area of ​​the buffer tank is at least three times the flow path cross-sectional area of ​​the first flow path in which the buffer tank is provided. The length of the buffer tank in the flow path direction is equal to or greater than the diameter of the flow path cross section of the buffer tank.

20. The substrate processing apparatus according to claim 19, wherein: Regarding the buffer tank, a volume of the buffer tank is 5 times or more of a target value of the supply amount of the gas in one pulse group.

21. The substrate processing apparatus according to claim 20, wherein: Regarding the buffer tank, a volume of the buffer tank is 10 times or more of a target value of the supply amount of the gas in one pulse group.

22. The substrate processing apparatus according to claim 19, wherein: The buffer tank is configured such that the volume of the buffer tank is variable. The control unit is further configured to be capable of executing a step of reducing the volume of the buffer tank so that the pressure of the buffer tank is constant during the duration of the pulse control.

23. The substrate processing apparatus according to claim 19, wherein: The buffer tank is configured to be capable of adjusting the temperature of the gas in the buffer tank. The control unit is further configured to be capable of executing a step of increasing the temperature of the gas in the buffer tank so that the pressure of the buffer tank is constant during the duration of the pulse control.

24. The substrate processing apparatus according to any one of claims 13 to 15, wherein: The substrate processing device comprises an upper electrode, The control unit is further configured to execute the step of supplying the gas from the gas supply unit to the vicinity of the center of the upper electrode, diffusing the gas in a diffusion chamber provided in the upper electrode, and introducing the gas into the substrate processing space.

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