Plasma processing apparatus and plasma processing method

Abstract

We will implement environmentally conscious processing of the circuit boards. [Solution] A plasma processing apparatus comprising a processing chamber, a gas supply unit, an RF power supply, and a control unit, wherein the control unit controls each part of the plasma processing apparatus to perform a process including: (A) preparing a substrate in the processing chamber; (B) supplying a first gas into the processing chamber and controlling the pressure in the processing chamber to a first pressure value within a first pressure range; (C) switching the gas supplied to the processing chamber from the first gas to a second gas, wherein the first gas has a lower degree of environmental impact than the second gas; (D) supplying the second gas into the processing chamber and controlling the pressure in the processing chamber to a second pressure value within a first pressure range; and (E) supplying RF power from the RF power supply to generate plasma from the second gas and performing processing of the substrate with the plasma.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a plasma processing apparatus and a plasma processing method.

BACKGROUND ART

[0002] For example, Patent Document 1 provides a method for manufacturing an electronic device using a plasma processing system. The method includes a first step of providing a new flow rate set value to each of pressure control type flow regulators interposed in the supply pipeline of each component gas in order to change the concentration of the process gas in the process chamber, and in the first step, each of the new flow rate set values provided to each flow regulator is a value obtained by calculating backward from the assumed changed process gas concentration on the condition that the total flow rate value is the same before and after the concentration change.

[0003] Patent Document 2 proposes a deposition method comprising the steps of supplying a first precursor to at least a first region of a plurality of regions, and supplying a first plasma to the first region such that a first material on the first region formed using the first precursor is deposited.

[0004] Patent Document 3 proposes a method of alternately repeating a predetermined number of times a deposition step of supplying a first gas through a first gas pipe to a diffusion chamber and into a chamber to perform plasma processing on a target object, and an etching step of supplying a second gas through a second gas pipe to the diffusion chamber and into the chamber to perform plasma processing on the target object.

PRIOR ART DOCUMENTS

PATENT DOCUMENTS

[0005]

PATENT DOCUMENT 1

PATENT DOCUMENT 2

PATENT DOCUMENT 3

SUMMARY OF THE INVENTION

[0006] This disclosure provides a technology that enables environmentally conscious processing of substrates. [Means for solving the problem]

[0007] According to one aspect of the present disclosure, a plasma processing apparatus is provided, comprising a processing chamber, a gas supply unit, an RF power supply, and a control unit, wherein the control unit is configured to control each part of the plasma processing apparatus to perform a process including: (A) preparing a substrate in the processing chamber; (B) supplying a first gas into the processing chamber and controlling the pressure in the processing chamber to a first pressure value within a first pressure range; (C) switching the gas supplied to the processing chamber from the first gas to a second gas, wherein the first gas has a lower degree of environmental impact than the second gas; (D) supplying the second gas into the processing chamber and controlling the pressure in the processing chamber to a second pressure value within a first pressure range; and (E) supplying RF power from the RF power supply to generate plasma from the second gas and performing processing of the substrate with the plasma. [Effects of the Invention]

[0008] From one perspective, it is possible to perform substrate processing that takes the environment into consideration. [Brief explanation of the drawing]

[0009] [Figure 1] An example of a diagram illustrating the configuration of a plasma processing system. [Figure 2] An example of a diagram illustrating the configuration of a capacitively coupled plasma processing apparatus. [Figure 3] (a) is a diagram showing an example of a plasma treatment method according to a reference example, and (b) is a diagram showing an example of a plasma treatment method according to an embodiment. [Figure 4]A flowchart showing the first embodiment of the plasma treatment method. [Figure 5] A diagram showing an example of the gas and flow rate used in the first embodiment of the plasma processing method. [Figure 6] A time chart showing the first and second embodiments of the plasma treatment method. [Figure 7] This is a flowchart showing a second embodiment of the plasma treatment method. [Figure 8] A diagram showing an example of the gas and flow rate used in the second embodiment of the plasma processing method. [Modes for carrying out the invention]

[0010] The following describes embodiments for implementing this disclosure with reference to the drawings. In each drawing, the same reference numerals are used for identical components, and redundant explanations may be omitted.

[0011] [Plasma Processing System] Figure 1 is an example diagram illustrating an example configuration of a plasma processing system. In one embodiment, the plasma processing system includes a plasma processing apparatus 1 and a control unit 2. The plasma processing system is an example of a substrate processing system, and the plasma processing apparatus 1 is an example of a substrate processing apparatus. The plasma processing apparatus 1 includes a plasma processing chamber (processing chamber) 10, a substrate support unit 11, and a plasma generation unit 12. The plasma processing chamber 10 has a plasma processing space. The plasma processing chamber 10 also has at least one gas supply port for supplying at least one processing gas to the plasma processing space, and at least one gas outlet for discharging gas from the plasma processing space. The gas supply port is connected to a gas supply unit 20, which will be described later, and the gas outlet is connected to an exhaust system 40, which will be described later. The substrate support unit 11 is located in the plasma processing space and has a substrate support surface for supporting a substrate.

[0012] The plasma generation unit 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma formed in the plasma processing space may be a capacitively coupled plasma (CCP), an inductively coupled plasma (ICP), an electron cyclotron resonance (ECR) plasma, a helicon wave excited plasma (HWP), or a surface wave plasma (SWP), etc. Various types of plasma generation units, including an AC (alternating current) plasma generation unit and a DC (direct current) plasma generation unit, may also be used. In one embodiment, the AC signal (AC power) used in the AC plasma generation unit has a frequency in the range of 100 kHz to 10 GHz. Therefore, the AC signal includes an RF (radio frequency) signal and a microwave signal. In one embodiment, the RF signal has a frequency in the range of 100 kHz to 150 MHz.

[0013] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to perform the various processes described herein. The control unit 2 may be configured to control each element of the plasma processing apparatus 1 to perform the various processes described herein. In one embodiment, some or all of the control unit 2 may be included in the plasma processing apparatus 1. The control unit 2 is implemented, for example, by a computer 2a. The control unit 2 may include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The functions implemented by the processing unit 2a1 described herein may be implemented in a circuit or processing circuitry, including a general-purpose processor, an application-specific processor, integrated circuits, ASICs (Application Specific Integrated Circuits), a CPU (Central Processing Unit), conventional circuitry, and / or a combination thereof, programmed to implement the functions described herein. A processor is considered a circuit or processing circuit, including transistors and other circuitry. A processor may be a programmed processor that executes a program stored in the storage unit 2a2. This program may be stored in the memory unit 2a2 in advance, or it may be retrieved via a medium when needed. The retrieved program is stored in the memory unit 2a2 and read from the memory unit 2a2 and executed by the processing unit 2a1. The medium may be various storage media readable by the computer 2a, or it may be a communication line connected to the communication interface 2a3. The memory unit 2a2 may include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), 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).In the present disclosure, a circuit, a unit, and a means are hardware programmed to implement a described function, or hardware configured to execute the described function. The hardware may be any hardware described in the present disclosure, or any hardware known to be programmed to implement or execute the described function. When the hardware is a processor that is considered to be a type of circuit, the circuit, the means, or the unit is a combination of the hardware and software used to configure the hardware and / or the processor.

[0014] [Plasma processing apparatus] Hereinafter, a configuration example of a capacitively coupled plasma processing apparatus as an example of the plasma processing apparatus 1 will be described. FIG. 2 is an example of a diagram for explaining a configuration example of the capacitively coupled plasma processing apparatus 1.

[0015] The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber (processing chamber) 10, a gas supply unit 20, a power supply system 30, and an exhaust system 40. Further, the plasma processing apparatus 1 includes a substrate support portion 11 and a gas introduction portion. The gas introduction portion is configured to introduce at least one processing gas into the plasma processing chamber 10. The gas introduction portion includes a shower head 13. The substrate support portion 11 is disposed inside the plasma processing chamber 10. The shower head 13 is disposed above the substrate support portion 11. In one embodiment, the shower head 13 constitutes at least a part of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the shower head 13, the side wall 10a of the plasma processing chamber 10, and the substrate support portion 11. The plasma processing chamber 10 is grounded. The shower head 13 and the substrate support portion 11 are electrically insulated from the housing of the plasma processing chamber 10.

[0016] The substrate support portion 11 includes a main body portion 111 and a ring assembly 112. The main body portion 111 has a central region 111a for supporting the substrate W and an annular region 111b for supporting the ring assembly 112. A wafer is an example of the substrate W. The annular region 111b of the main body portion 111 surrounds the central region 111a of the main body portion 111 in a plan view. The substrate W is placed on the central region 111a of the main body portion 111, and the ring assembly 112 is placed on the annular region 111b of the main body portion 111 so as to surround the substrate W on the central region 111a of the main body portion 111. Therefore, the central region 111a is also called the substrate support surface for supporting the substrate W, and the annular region 111b is also called the ring support surface for supporting the ring assembly 112.

[0017] In one embodiment, the main body portion 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive member. The conductive member of the base 1110 can function as a lower electrode. The electrostatic chuck 1111 is disposed on the base 1110. The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic chuck electrode 1111b disposed within the ceramic member 1111a. The electrostatic chuck electrode 1111b is also referred to as a clamping electrode. In one embodiment, the electrostatic chuck electrode 1111b is electrically connected or coupled to a chuck power supply. The chuck power supply may be a DC power supply or an AC power supply. The ceramic member 1111a has a central region 111a. In one embodiment, the ceramic member 1111a also has an annular region 111b. Other members surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member, may have the annular region 111b. In this case, the ring assembly 112 may be disposed on the annular electrostatic chuck or the annular insulating member, or may be disposed on both the electrostatic chuck 1111 and the annular insulating member. Further, at least one bias electrode electrically connected or coupled to a power supply 31 and / or a power supply 32 to be described later may be disposed within the ceramic member 1111a. In this case, the at least one bias electrode functions as a lower electrode. Further, the conductive member of the base 1110 and the bias electrode in the ceramic member 1111a may function as a plurality of lower electrodes. In one embodiment, a first voltage generation unit 32a, which functions as a voltage pulse generation unit to be described later, is electrically connected or coupled to the bias electrode in the ceramic member 1111a, and a first RF generation unit 31a to be described later is electrically connected or coupled to the conductive member of the base 1110. Further, the electrostatic chuck electrode 1111b may function as a lower electrode. Accordingly, the substrate support portion 11 includes at least one lower electrode.

[0018] The ring assembly 112 includes one or a plurality of annular members. In one embodiment, the one or more annular 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.

[0019] The substrate support section 11 may also include a temperature control module configured to adjust at least one of the electrostatic chuck 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 through the flow path 1110a. In one embodiment, the flow path 1110a is formed within the base 1110, and one or more heaters are arranged within the ceramic member 1111a of the electrostatic chuck 1111. The substrate support section 11 may also include a heat transfer gas supply section configured to supply heat transfer gas to the gap between the back surface of the substrate W and the central region 111a.

[0020] The showerhead 13 is configured to introduce at least one processing gas from the gas supply unit 20 into the plasma processing space 10s. The showerhead 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and a plurality of gas inlet ports 13c. The processing gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the plasma processing space 10s through the plurality of gas inlet ports 13c. The showerhead 13 also includes at least one upper electrode. In addition to the showerhead 13, the gas introduction unit may also include one or more side gas injectors (SGIs) attached to one or more openings formed in the side wall 10a.

[0021] 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 to the shower head 13 from a corresponding gas source 21 via a corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Furthermore, the gas supply unit 20 may include at least one flow modulation device that modulates or pulses the flow rate of at least one processing gas.

[0022] The power supply system 30 includes a power supply (RF power supply) 31 that is electrically connected to or coupled to the plasma processing chamber 10. In one embodiment, the power supply 31 is electrically connected to or coupled to the plasma processing chamber 10 via at least one impedance matcher. The impedance matcher may be a mechanically controlled matcher or an electronically controlled matcher. The 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. This generates plasma from at least one processing gas supplied to the plasma processing space 10s. Thus, the power supply 31 can function as at least part of the plasma generation unit 12. In addition, by supplying a bias RF signal to at least one lower electrode, a bias potential is generated on the substrate W, and ionic components in the formed plasma can be drawn into the substrate W.

[0023] The power supply 31 includes a first RF generation unit 31a and a second RF generation unit 31b. The first RF generation unit 31a is electrically connected or coupled to at least one lower electrode and / or at least one upper electrode and is configured to generate a source RF signal (source RF power) to generate plasma in the plasma processing space 10s. In one embodiment, the first RF generation unit 31a is electrically connected or coupled to at least one lower electrode and / or at least one upper electrode via at least one impedance matcher. 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 generation unit 31a may 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.

[0024] The second RF generation unit 31b is electrically connected to or coupled to at least one lower electrode and is configured to generate a bias RF signal (bias RF power). In one embodiment, the second RF generation unit 31b is electrically connected to or coupled to at least one lower electrode via at least one impedance matcher. If the first RF generation unit 31a is electrically connected to or coupled to a lower electrode, the second RF generation unit 31b may be electrically connected to or coupled to the same lower electrode, or it may be electrically connected to or coupled to a different lower electrode. 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 lower frequency than the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 100 kHz to 60 MHz. In one embodiment, the second RF generation unit 31b may 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 various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0025] The power supply system 30 may also include a power supply 32 that is electrically connected to or coupled to the plasma processing chamber 10. The power supply 32 includes a first voltage generation unit 32a and a second voltage generation unit 32b. In one embodiment, the first voltage generation unit 32a is electrically connected to or coupled to at least one lower electrode and configured to generate a first voltage signal. The generated first voltage signal is applied to at least one lower electrode. In one embodiment, the second voltage generation unit 32b is electrically connected to or coupled to at least one upper electrode and configured to generate a second voltage signal. The generated second voltage signal is applied to at least one upper electrode.

[0026] In various embodiments, the first and / or second voltage signals may be pulsed. In this case, the first voltage generation unit 32a and / or the second voltage generation unit 32b function as voltage pulse generation units configured to generate a sequence of voltage pulses. Thus, the sequence of voltage pulses is applied to at least one lower electrode and / or at least one upper electrode. In one embodiment, the sequence of voltage pulses has multiple cycles, each cycle including a burst of voltage pulses in a first period and a constant reference voltage in a second period. That is, in the sequence of voltage pulses, bursts of voltage pulses are repeated. The absolute value of the voltage level of the voltage pulse is greater than the absolute value of the voltage level of the reference voltage. The voltage pulse may have an arbitrary waveform having a rectangular, trapezoidal, triangular, or a combination thereof, and the arbitrary waveform may change over time. The voltage pulse may have positive polarity or negative polarity. The sequence of voltage pulses may also include one or more positive voltage pulses and one or more negative voltage pulses within one cycle. The first and second voltage generation units 32a and 32b may be provided in addition to the power supply 31, and the first voltage generation unit 32a may be provided in place of the second RF generation unit 31b.

[0027] The exhaust system 40 may be connected to, for example, a gas outlet 10e located at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure regulating valve regulates the pressure in the plasma processing space 10s. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0028] [Plasma treatment method] Before initiating plasma treatment of the substrate W, it is necessary to adjust the atmosphere inside the plasma treatment chamber 10 to match the process conditions. For this reason, a stabilization step is performed before the substrate W treatment step to maintain the pressure inside the plasma treatment chamber 10 at a pressure that matches the process conditions. Figure 3(a) shows an example of a plasma treatment method according to a reference example.

[0029] In the reference example shown in Figure 3(a), process gas is supplied from time t0 in the stabilization step to control the pressure inside the plasma processing chamber 10 to match the process conditions. The process gas is the gas used in the processing steps performed after the stabilization step. Gases containing element F, such as CxFy gas, included in the process gas are GH gases (Green House Gases) and may be used, for example, as etching gases. Therefore, in the stabilization step, process gas containing GH gas may be supplied. In the stabilization step of Figure 3(a), a process gas with a constant total flow rate is supplied, as shown by line E. The GH gas shown by line C is one of the gases included in that process gas and is controlled to a constant flow rate during the stabilization step.

[0030] The exhaust system 40 exhausts the inside of the plasma processing chamber 10 while supplying process gas containing GH gas into the plasma processing chamber 10. At this time, the pressure inside the plasma processing space 10s is adjusted by the control valve. As a result, the pressure inside the plasma processing space 10s increases from time t0 to time t1 as shown by line A, and is controlled to be constant thereafter.

[0031] After controlling the pressure to a constant level in the stabilization step, the processing step begins. In Figure 3(a), at time t3, the RF power shown by line B is supplied, generating plasma from the process gas containing GH gas. This plasma is then used to perform processes such as etching on the substrate W. As shown by line E, in this reference example, the total flow rate of the process gas containing GH gas remains constant during both the stabilization and processing steps.

[0032] However, since the use of GH gas contributes to global warming, it is preferable to reduce its use as much as possible with environmental considerations in mind. Therefore, in an example of the plasma processing method according to the embodiment shown in Figure 3(b), in the stabilization step, Ar gas (alternative gas) shown on line D is supplied instead of GH gas (specific gas). In other words, the flow rates of GH gas and Ar gas are equal, and the total flow rate of process gas shown on line E does not change.

[0033] Here, Ar gas has a lower environmental impact compared to GH gas. In other words, Ar gas has a lower greenhouse effect compared to GH gas. To put it another way, Ar gas has a lower global warming potential (GWP) compared to GH gas.

[0034] In the stabilization step, the inside of the plasma processing chamber 10 is exhausted by the exhaust system 40, while a process gas, in which GH gas is replaced with Ar gas, is supplied into the plasma processing chamber 10. At this time, the pressure inside the plasma processing space 10s is adjusted by the pressure regulating valve. As a result, the pressure inside the plasma processing space 10s increases from time t0 to time t1 as shown by line A, and is controlled to be constant thereafter.

[0035] After controlling the pressure to a constant level in the stabilization step, a transition step is performed before the processing step, switching from Ar gas (alternative gas) to GH gas (specific gas) as shown by lines C and D. In this embodiment shown in Figure 3(b), the supply of Ar gas is stopped and the supply of GH gas is started at time t2. The flow rate of GH gas shown by line C is the same as the flow rate of Ar gas shown by line D. Therefore, as shown by line E, the total flow rate of the process gas, including GH gas, supplied in the transition step is the same as the total flow rate of the process gas, including Ar gas, supplied in the stabilization step. As a result, the pressure inside the plasma processing chamber 10 is controlled to a constant level.

[0036] Subsequently, the processing step is initiated. In this embodiment shown in Figure 3(b), at time t3, RF power as shown by line B is supplied, plasma is generated from the process gas containing GH gas, and etching and other processes are performed on the substrate W using this plasma. As shown by line E, in this embodiment, the total flow rate of gas supplied to the plasma processing chamber 10 is the same in the stabilization step, the transition step, and the processing step. Therefore, in the stabilization step, the pressure inside the plasma processing chamber 10 can be controlled to a pressure that matches the process conditions and then maintained at that pressure until the processing step. In addition, Ar gas is used as a substitute gas for GH gas in the stabilization step. Furthermore, a transition step is provided between the stabilization step and the processing step, and in the transition step, Ar gas is switched to GH gas to adjust the atmosphere inside the plasma processing chamber 10 to a state that matches the process conditions. Subsequently, processing is performed on the substrate W in the processing step. This makes it possible to reduce the amount of GH gas used without affecting the processing of the substrate W, and to perform processing of the substrate W while considering the environment.

[0037] [First Embodiment] A first embodiment of the plasma treatment method according to the above-described embodiment will be explained with reference to Figures 4 to 6. Figure 4 is a flowchart of the first embodiment of the plasma treatment method. Figure 5 is a diagram showing an example of the gas used in the first embodiment of the plasma treatment method and its flow rate. Figure 6 is a time chart showing the state of the first embodiment of the plasma treatment method from time t0 to time t4. The first embodiment of the plasma treatment method shown in Figure 4 will be described below.

[0038] (Step S1: Prepare the circuit board) When processing of the first embodiment begins, in step S1, the control unit 2 prepares the substrate W by transporting it into the plasma processing chamber 10 and placing it on the substrate support unit 11.

[0039] (Step S2: Setting the first gas) Next, in step S2, the control unit 2 sets the first gas, which includes the substitute gas. The "first gas" is one or more gases supplied in the stabilization step, and includes the substitute gas. The "second gas," which will be described later, is one or more process gases supplied in the processing step, and includes a specific gas. The "second gas" is the gas used for processing the substrate W. The first gas is a gas in which some of the gases (specific gases) of the second gas have been replaced with the substitute gas. Therefore, the second gas contains gases different from the first gas.

[0040] The gas type and flow rate of each gas for the second gas are pre-set in the recipe stored in the memory unit 2a2. The gas type and flow rate of each gas for the first gas are pre-set in the parameters stored in the memory unit 2a2. In step S2, the control unit 2 obtains the gas type and flow rate of each gas for the first gas from the parameters and sets the first gas.

[0041] Figure 5(a) shows an example of the set gas types and flow rates of each gas for the first gas. Figure 5(b) shows an example of the set gas types and flow rates of each gas for the second gas. The first and second gases are not limited to these gases. For example, the second gas may include a gas having at least one element selected from C, F, or Xe as a specific gas. The following explanation will use the case where GH gas is included as the specific gas as an example. In this specification, "GH gas" is a gas having at least one element selected from C or F. CxFy gas is an example of GH gas. In this example, among the second gas consisting of CF4 gas, Ar gas, and O2 gas, CF4 gas is the GH gas (specific gas).

[0042] In the second gas, the flow rates of CF4 gas, Ar gas, and O2 gas are set to 100 sccm, 400 sccm, and 100 sccm, respectively. The total flow rate of the second gas is 600 sccm. In step S2, the first gas is supplied, in which GH gas (specific gas) from the second gas is replaced with an alternative gas.

[0043] Here, Ar gas, which is included in the second gas, is used as a substitute gas for CF4 gas, which is the GH gas. However, the substitute gas does not have to be a gas included in the second gas. The control unit 2 sets the Ar gas (which is obtained by replacing CF4 gas (specific gas) with Ar gas (substitute gas) from the second gas shown in Figure 5(b) and the O2 gas as the first gas, and sets the flow rate of Ar gas to 500 sccm by adding the flow rate of CF4 gas (100 sccm) to the flow rate of Ar gas (400 sccm). The flow rate of O2 gas is not changed. As a result, as shown in Figure 5(a), the flow rates of Ar gas and O2 gas in the first gas are set to 500 sccm and 100 sccm, respectively. The total flow rate of the first gas is 600 sccm, which is the same as the total flow rate of the second gas.

[0044] Here, the alternative gas (Ar gas) is a gas that has a smaller environmental impact compared to the specified gas (CF4 gas). In other words, the alternative gas (Ar gas) is a gas that has a smaller greenhouse effect compared to the specified gas (CF4 gas). To put it another way, the alternative gas (Ar gas) is a gas with a smaller global warming potential (GWP) compared to the specified gas (CF4 gas).

[0045] In other words, the first gas, which includes the alternative gas (Ar gas), has a lower environmental impact compared to the second gas, which includes the specific gas (CF4 gas). In other words, the first gas has a lower greenhouse effect compared to the second gas. In further terms, the first gas has a lower global warming potential (GWP) compared to the second gas.

[0046] (Step S3: Stabilization step) Next, in step S3, the control unit 2 exhausts the inside of the plasma processing chamber 10 with the exhaust system 40, while supplying a first gas containing a substitute gas from the gas supply unit 20 into the plasma processing chamber 10 at a set flow rate. In the example shown in Figure 5(a), the control unit 2 supplies Ar gas and O2 gas as the first gas at rates of 500 sccm and 100 sccm, respectively, during the stabilization step. In other words, the total flow rate of the first gas is 600 sccm. The pressure inside the plasma processing space 10s is also adjusted by the pressure regulating valve. This controls the pressure inside the plasma processing chamber 10 to a first pressure value P1 within the first pressure range RP1.

[0047] Here, the first pressure range RP1 (see Figure 6) is the pressure range in which a plasma of the second gas containing GH gas can be stably generated within the plasma processing chamber 10. The second pressure value P2, which will be described later, is a pressure value within the first pressure range RP1. Furthermore, the second pressure value P2 is the pressure value of the process conditions controlled in the processing steps (steps S8 to S10) described later, and is pre-set in a recipe stored in the memory unit 2a2, for example.

[0048] Furthermore, the first pressure value P1 is a pressure value within the first pressure range RP1. The first pressure value P1 is pre-set in a recipe stored in the memory unit 2a2, for example. The first pressure value P1 may be approximately equal to the second pressure value P2. For example, the ratio of the second pressure value P2 to the first pressure value P1 may be in the range of 0.95 to 1.05 (0.95 ≤ P2 / P1 ≤ 1.05). Also, the first pressure value P1 may be equal to the second pressure value P2 (P1 = P2).

[0049] In the time chart of Figure 6, the stabilization step is performed between time t0 and time t2. From time t0, the supply of the first gas (Ar gas, O2 gas) containing Ar gas (shown as the first alternative gas in Figure 6) is started. At this time, the total flow rate S1 of the first gas is controlled to 600 sccm. Due to the supply of the first gas, the pressure inside the plasma processing chamber 10 increases, and at time t1, the pressure inside the plasma processing chamber 10 reaches a first pressure value P1 within the first pressure range RP1, and is then controlled to be constant.

[0050] (Step S4: Determination of the end of the stabilization step) Next, in step S4, the control unit 2 determines whether the processing time for the stabilization step has elapsed. The processing time for the stabilization step is predetermined in a recipe stored in the storage unit 2a2, for example.

[0051] In step S4, the control unit 2 repeats the process of step S3 until the processing time for the stabilization step has elapsed. After the processing time for the stabilization step has elapsed, the control unit 2 determines that the stabilization step is finished and proceeds to step S5.

[0052] (Step S5: Setting the second gas) Next, in step S5, the control unit 2 sets the second gas. In Figure 5(b), the CF4 gas is the GH gas that was replaced with Ar gas in the stabilization step, and of the 500 sccm flow rate of Ar gas contained in the first gas in Figure 5(a), 100 sccm is the flow rate of the substitute gas supplied in place of the CF4 gas.

[0053] Therefore, the control unit 2 sets CF4 gas, Ar gas, and O2 gas as the second gas, and sets the flow rates of each gas to 100 sccm, 400 sccm, and 100 sccm. The total flow rate of the second gas is 600 sccm, which is the same as the total flow rate of the first gas. The control unit 2 only needs to obtain the gas types and flow rates of each gas for the second gas as described above from the recipe stored in the memory unit 2a2.

[0054] (Step S6: Transition Step) Next, in step S6, the control unit 2 switches the gas supplied from the gas supply unit 20 from the first gas to the second gas. The control unit 2 supplies the second gas, consisting of CF4 gas, Ar gas, and O2 gas, at flow rates of 100 sccm, 400 sccm, and 100 sccm. Any gas from the first gas that is not included in the second gas is stopped. For example, Ar gas, which functions as a substitute gas (the first substitute gas in Figure 6) from the first gas, is also included in the second gas. Therefore, in the second gas, the flow rate of Ar gas included in the second gas is reduced by the amount of CF4 gas that was substituted using Ar gas in the first gas (i.e., 100 sccm), and as a result, Ar gas is supplied at 400 sccm. In addition, the pressure in the plasma processing space 10s is adjusted by the pressure regulating valve. This controls the pressure in the plasma processing chamber 10 to the second pressure value P2 within the first pressure range RP1.

[0055] In the time chart of Figure 6, the transition step is performed between time t2 and time t3. The explanation will also be given as an example where the first pressure value P1 and the second pressure value P2 are equal. In the first embodiment, at time t2, the flow rate of the substitute gas (first substitute gas) from the Ar gas is stopped, and the supply of CF4 gas (GH gas) is started. Since the total flow rate of the second gas is equal to the total flow rate of the first gas, the pressure inside the plasma processing chamber 10 is maintained at the second pressure value P2 (= first pressure value P1) within the first pressure range RP1. Even if the first pressure value P1 and the second pressure value P2 are different, since the first pressure value P1 and the second pressure value P2 are approximately equal, and the total flow rate of the second gas is equal to the total flow rate of the first gas, the pressure inside the plasma processing chamber 10 is quickly controlled from the first pressure value P1 to the second pressure value P2 within the first pressure range RP1.

[0056] (Step S7: Determining the end of the transition step) Next, in step S7, the control unit 2 determines whether the processing time for the transition step has elapsed. The processing time for the transition step is predetermined in a recipe stored in the storage unit 2a2, for example.

[0057] In step S7, the control unit 2 repeats the process in step S6 until the processing time for the transition step has elapsed. After the processing time for the transition step has elapsed, the control unit 2 determines that the transition step is finished and proceeds to step S8.

[0058] (Steps S8, S9: Processing steps) Next, in step S8, RF power is supplied from the power supply 31. The RF power is supplied to at least one of the lower electrode or the upper electrode.

[0059] Next, in step S9, the control unit 2 generates plasma from the second gas and performs processing on the substrate W using the plasma. For example, etching is performed on the substrate W using the plasma.

[0060] In the time chart of Figure 6, the processing step is performed between time t3 and time t4. At time t3, RF power is supplied from power supply 31, and between time t3 and time t4, plasma is generated from the second gas and the substrate W is plasma-treated. During the processing step, the pressure inside the plasma processing chamber 10 is maintained at the second pressure value P2 within the first pressure range RP1.

[0061] (Step S10: Determination of the end of the processing step) Next, in step S10, the control unit 2 determines whether the processing time for the processing step has elapsed. The processing time for the processing step is predetermined in a recipe stored in the storage unit 2a2, for example.

[0062] In step S10, the control unit 2 performs the processing in steps S8 and S9 until the processing time for the processing step has elapsed. After the processing time for the processing step has elapsed, the control unit 2 determines that the processing step is finished and proceeds to step S11.

[0063] (Step S11: Unloading the circuit board) In step S11, the control unit 2 stops supplying the second gas and RF power, removes the substrate W, and terminates the process. In the time chart of Figure 6, the supply of the second gas and RF power is stopped at time t4, and the processing step in the first embodiment is terminated.

[0064] As described above, in the stabilization step, a first gas containing an alternative gas is supplied into the plasma processing chamber 10, and the pressure inside the plasma processing chamber 10 is controlled to a first pressure value P1. In the transition step, the gas supplied into the plasma processing chamber 10 is switched from the first gas to the second gas, and a second gas containing a specific gas is supplied into the plasma processing chamber 10, and the pressure inside the plasma processing chamber 10 is controlled to a second pressure value P2. In the processing step, RF power is supplied from the power supply 31 to generate a plasma of the second gas containing the specific gas inside the plasma processing chamber 10, and the substrate W is subjected to a desired plasma treatment (e.g., etching).

[0065] Thus, in the first embodiment of the plasma treatment method, plasma treatment can be performed on the substrate W using plasma generated from a second gas containing a specific gas. Furthermore, in the stabilization step, the amount of specific gas used can be reduced by supplying a first gas containing an alternative gas into the plasma treatment chamber 10 and controlling the pressure inside the plasma treatment chamber 10. The specific gas is, for example, GH gas. By reducing the amount of GH gas used, environmentally conscious processing of the substrate W can be performed.

[0066] Furthermore, the first pressure value P1 and the second pressure value P2 are approximately equal. This allows the pressure inside the plasma processing chamber 10 to be quickly controlled to the second pressure value P2, which is the pressure in the processing step, after switching the gas supplied to the plasma processing chamber 10 from the first gas to the second gas during the transition step. Thus, the amount of specific gas used during the transition step can be reduced.

[0067] Furthermore, it is more preferable that the first pressure value P1 and the second pressure value P2 are equal. This allows for a further reduction in the amount of specific gas used during the transition step.

[0068] Furthermore, although it has been explained that the flow rate of the substitute gas contained in the first gas and the flow rate of the specific gas contained in the second gas are the same, and the total flow rate of the first gas and the total flow rate of the second gas are the same (total flow rate S1), this is not the only possible explanation. Also, the flow rate of the substitute gas contained in the first gas and the flow rate of the specific gas contained in the second gas may be approximately the same, and the total flow rate of the first gas and the total flow rate of the second gas may be approximately the same. For example, the ratio of the total flow rate S12 of the second gas to the total flow rate S11 of the first gas may be in the range of 0.95 to 1.05 (0.95 ≤ S12 / S11 ≤ 1.05).

[0069] [Second Example] Next, a second embodiment of the plasma processing method according to the embodiment will be described with reference to Figures 6 to 8. The time chart shown in Figure 6 from time t0 to time t7 is a time chart showing the state of the second embodiment of the plasma processing method. Figure 7 is a flowchart of the second embodiment of the plasma processing method. Figure 8 is a diagram showing an example of the gas used in the second embodiment of the plasma processing method and its flow rate.

[0070] In the second embodiment of the plasma treatment method shown in Figure 7, steps that perform the same treatment as in the first embodiment of the plasma treatment method shown in Figure 4 are assigned the same step number. This simplifies the explanation of the treatment for steps with the same step number as in Figure 4.

[0071] When processing of the second embodiment begins, in step S1, the control unit 2 prepares the substrate W, and then in step S2a, it sets the first gas including the alternative gas (first alternative gas).

[0072] Figure 8(a) shows an example of the set gas types and flow rates for the first gas. Figure 8(b) shows an example of the set gas types and flow rates for the second gas. The first and second gases are not limited to these gases. In this example, among the second gases consisting of C4F6 gas, C4F8 gas, CO gas, O2 gas, and N2 gas, C4F6 gas and C4F8 gas are GH gases (first specified gases).

[0073] In the second gas supply, the flow rates of C4F6 gas, C4F8 gas, CO gas, O2 gas, and N2 gas are set to 50 sccm, 50 sccm, 50 sccm, 50 sccm, and 50 sccm, respectively. The total flow rate of the second gas supply is 250 sccm. In step S2a, the first gas supply is provided, in which GH gas (first specified gas) is replaced with an alternative gas (first alternative gas) from the second gas supply.

[0074] Here, CO gas, which is included in the second gas, is used as a substitute gas for the GH gases C4F6 gas and C4F8 gas. However, the substitute gas does not have to be a gas included in the second gas. The control unit 2 sets the CO gas (obtained by replacing C4F6 gas and C4F8 gas with CO gas) O2 gas and N2 gas from the second gas shown in Figure 8(b) as the first gas, and sets the CO gas flow rate to 150 sccm by adding the total flow rate of C4F6 gas and C4F8 gas from the second gas (100 sccm) to the CO gas flow rate (50 sccm). The flow rates of O2 gas and N2 gas are not changed. As a result, as shown in Figure 8(a), the flow rates of CO gas, O2 gas, and N2 gas from the first gas are set to 150 sccm, 50 sccm, and 50 sccm, respectively. The total flow rate of the first gas is 250 sccm, which is the same as the total flow rate of the second gas.

[0075] Here, the first alternative gas (CO gas) is a gas that has a smaller environmental impact compared to the first specified gas (C4F6 gas, C4F8 gas). In other words, the alternative gas (CO gas) is a gas that has a smaller greenhouse effect compared to the specified gas (C4F6 gas, C4F8 gas). To put it another way, the alternative gas (CO gas) is a gas with a smaller global warming potential (GWP) compared to the specified gas (C4F6 gas, C4F8 gas).

[0076] In other words, the first gas, which includes alternative gases (CO gas), has a lower environmental impact compared to the second gas, which includes specific gases (C4F6 gas, C4F8 gas). In other words, the first gas has a lower greenhouse effect compared to the second gas. In further terms, the first gas has a lower global warming potential (GWP) compared to the second gas.

[0077] In step S2a, the control unit 2 sets the variable n to "1", then proceeds to step S3a and executes the stabilization step. The stabilization step is performed between time t0 and time t2 as shown in Figure 6.

[0078] In the stabilization step, the control unit 2 exhausts the inside of the plasma processing chamber 10 using the exhaust system 40, while simultaneously supplying the nth gas (first gas), which includes an alternative gas, into the plasma processing chamber 10 at a set flow rate. For example, the first gas shown in Figure 8(a) is supplied, and the first alternative gas in Figure 6 is CO gas. In addition, the pressure inside the plasma processing space 10s is adjusted by the pressure regulating valve. This controls the pressure inside the plasma processing chamber 10 to a first pressure value P1 within the first pressure range RP1.

[0079] Here, the first pressure range RP1 (see Figure 6) is the pressure range in which a plasma of the second gas containing GH gas can be stably generated within the plasma processing chamber 10. The second pressure value P2, which will be described later, is the pressure value within the first pressure range RP1. The second pressure value P2 is also the pressure value of the process conditions controlled in the processing steps (steps S8, S9a, S10) described later, and is pre-set in a recipe stored in the memory unit 2a2, for example.

[0080] Furthermore, the first pressure value P1 is a pressure value within the first pressure range RP1. The first pressure value P1 is pre-set in a recipe stored in the memory unit 2a2, for example. The first pressure value P1 may be equal to the second pressure value P2 (P1=P2). Also, the first pressure value P1 may be approximately equal to the second pressure value P2. For example, the ratio of the second pressure value P2 to the first pressure value P1 may be in the range of 0.95 to 1.05 (0.95≦P2 / P1≦1.05).

[0081] Next, in step S3a, the control unit 2 performs the processing of step S3a until it determines that the processing time for the stabilization step has elapsed. After the processing time for the stabilization step has elapsed, it proceeds to step S5a and sets the (n+1)th gas (second gas) containing GH gas. In Figure 8(b), the C4F6 gas and C4F8 gas of the second gas are the GH gas that was replaced by CO gas in the stabilization step. Of the 150 sccm flow rate of CO gas contained in the first gas in Figure 8(a), 50 sccm and 50 sccm are the flow rates of the substitute gases supplied in place of C4F6 gas and C4F8 gas.

[0082] Therefore, the control unit 2 sets C4F6 gas, C4F8 gas, CO gas, O2 gas, and N2 gas as the second gas, and sets the flow rate of each gas to 50 sccm, 50 sccm, 50 sccm, 50 sccm, and 50 sccm. The total flow rate of the second gas is 250 sccm, which is the same as the total flow rate of the first gas.

[0083] Next, in step S6a, the control unit 2 switches the gas supplied from the gas supply unit 20 from the first gas to the second gas. The control unit 2 supplies the second gas, consisting of C4F6 gas, C4F8 gas, CO gas, O2 gas, and N2 gas, at flow rates of 50 sccm, 50 sccm, 50 sccm, 50 sccm, and 50 sccm. Any gas from the first gas that is not included in the second gas is stopped. For example, CO gas, which functions as a substitute gas (first substitute gas in Figure 6) among the first gases, is also included in the second gas. Therefore, in the second gas, the flow rate of CO gas included in the second gas is reduced by the amount of C4F6 gas and C4F8 gas that were substituted using CO gas in the first gas (i.e., 100 sccm), and as a result, CO gas is supplied at 50 sccm. In addition, the pressure in the plasma processing space 10s is adjusted by the pressure regulating valve. This controls the pressure in the plasma processing chamber 10 to the second pressure value P2 within the first pressure range RP1.

[0084] In the time chart of Figure 6, the transition step is performed between time t2 and time t3. The explanation will also be given as an example where the first pressure value P1 and the second pressure value P2 are equal. In the second embodiment, at time t2, the flow rate of the substitute gas (first substitute gas) from the CO gas is stopped, and the supply of C4F6 gas and C4F8 gas (GH gas) is started. Since the total flow rate of the second gas is equal to the total flow rate of the first gas, the pressure inside the plasma processing chamber 10 is maintained at the second pressure value P2 (= first pressure value P1) within the first pressure range RP1. Even if the first pressure value P1 and the second pressure value P2 are different, since the first pressure value P1 and the second pressure value P2 are equal or approximately equal, and the total flow rate of the second gas is equal to the total flow rate of the first gas, the pressure inside the plasma processing chamber 10 is quickly controlled from the first pressure value P1 to the second pressure value P2 within the first pressure range RP1.

[0085] Next, in step S7, the control unit 2 performs the processing in step S6a until it determines that the processing time for the transition step has elapsed. After the processing time for the transition step has elapsed, it proceeds to step S8 and supplies RF power. Next, in step S9a, the control unit 2 generates plasma from the (n+1)th gas (second gas) and performs processing on the substrate W using the plasma. For example, etching is performed on the substrate W using the plasma. In the time chart of Figure 6, the processing steps are performed between time t3 and time t4.

[0086] Next, in step S10, the control unit 2 performs the processing in steps S8 and S9a until it determines that the processing time for the processing step has elapsed, and after the processing time for the processing step has elapsed, proceeds to step S20a.

[0087] In step S20a, the control unit 2 stops supplying the (n+1)th gas (second gas) and RF power, and proceeds to step S21 to determine if there is a next step. If a next step is set in the recipe, the control unit 2 determines "YES" and proceeds to step S22.

[0088] In step S22, the control unit 2 adds "2" to the variable n (i.e., n=3) and sets the nth gas (third gas) which includes the substitute gas for the next step. In the next step, the "third gas" is one or more gases to be supplied in the next stabilization step, and includes the substitute gas. The "fourth gas," described later, is one or more process gases to be supplied in the next processing step, and is the gas used for processing the substrate W. The third gas is a gas in which a part of the fourth gas (second specific gas) is replaced with a substitute gas (second substitute gas). Therefore, the fourth gas includes a gas different from the third gas.

[0089] Figure 8(c) shows an example of the gas type and flow rate of the third gas. Figure 8(d) shows an example of the gas type and flow rate of the fourth gas. The third and fourth gases are not limited to these gases. For example, the fourth gas may include a gas having at least one element selected from C, F, or Xe as the second specified gas. The following explanation will use the case where Xe gas is included as the second specified gas as an example. In the next step, the Xe gas (second specified gas) contained in the fourth gas is replaced with Ar gas (second substitute gas) contained in the third gas. Xe gas is more difficult to obtain and more expensive than inert gases (noble gases) such as Ar gas. Therefore, in order to reduce costs and not be affected by the production status of Xe gas in a particular country, it is preferable to replace Xe gas with an inert gas such as Ar gas.

[0090] Therefore, in this example, the Xe gas (second specified gas) contained in the fourth gas is replaced with Ar gas (second alternative gas) in the third gas. If the fourth gas has a total flow rate of 500 sccm, of which 300 sccm is Xe gas, then the third gas has a total flow rate of 500 sccm, of which 300 sccm is Ar gas, as shown in Figure 8(c).

[0091] The fourth gas is used for processing the substrate W in the next processing step, and the type of gas and the flow rate of each gas are preset in a recipe stored in, for example, the memory unit 2a2. In the next stabilization step, a third gas is supplied in which the Xe gas of the fourth gas is replaced with Ar gas.

[0092] That is, after executing the process in step S22, the process returns to step S3a and the next stabilization step is performed. In the time chart of Figure 6, the next stabilization step is performed between time t4 and time t5. In the stabilization step, the nth gas (third gas) is supplied and the pressure in the plasma processing chamber 10 is controlled to a third pressure value P3 within the second pressure range RP2. The third gas includes Ar gas (second alternative gas in Figure 6) but does not include Xe gas. The third pressure value P3 may be different from or the same as the first pressure value P1 and the second pressure value P2.

[0093] Here, the second pressure range RP2 (see Figure 6) is the pressure range in which a plasma of the fourth gas containing Xe gas can be stably generated within the plasma processing chamber 10. The fourth pressure value P4, described later, is a pressure value within the second pressure range RP2. Furthermore, the fourth pressure value P4 is a pressure value of the process conditions controlled in the processing steps (steps S8 to S10) described later, and is pre-set, for example, in a recipe stored in the memory unit 2a2.

[0094] Furthermore, the third pressure value P3 is a pressure value within the second pressure range RP2. The third pressure value P3 is pre-set in a recipe stored in the memory unit 2a2, for example. The third pressure value P3 may be approximately equal to the fourth pressure value P4. For example, the ratio of the fourth pressure value P4 to the third pressure value P3 may be in the range of 0.95 to 1.05 (0.95 ≤ P4 / P3 ≤ 1.05). Also, the third pressure value P3 may be equal to the fourth pressure value P4 (P1 = P2).

[0095] In step S4, when it is determined that the processing time for the stabilization step has elapsed, the process proceeds to step S5a, where the control unit 2 sets the (n+1)th gas (fourth gas). Next, in step S6a, the control unit 2 executes a transition step. In the examples of Figures 8(c) and (d), the control unit 2 replaces the Ar gas, which is the substitute gas for the third gas, with Xe gas in the fourth gas, and controls the flow rate of the Xe gas to be the same as the flow rate of the Ar gas, 300 sccm, at time t5. At time t5, the Ar gas (second substitute gas) is stopped. In the time chart of Figure 6, the transition step is performed between time t5 and time t6. The total flow rate S2 of the fourth gas is controlled to be the same as the total flow rate S2 of the third gas. The total flow rate S2 may be different from or the same as the total flow rate S1. In addition, the pressure in the plasma processing space 10s is adjusted by the pressure regulating valve. As a result, the pressure in the plasma processing chamber 10 is controlled to the fourth pressure value P4 within the second pressure range RP2.

[0096] In step S7, if it is determined that the processing time for the transition step has elapsed, the process proceeds to step S8 and RF power is supplied. Next, in step S9a, the control unit 2 generates plasma from the (n+1)th gas (fourth gas) and processes the substrate W using the plasma. In the time chart of Figure 6, the processing step is performed between time t6 and time t7.

[0097] In step S10, after the processing time for the processing step has elapsed, the control unit 2 proceeds to step S20a and stops supplying the fourth gas and RF power. Next, in step S21, the control unit 2 determines whether there is a next step. If the control unit 2 determines that there is a next step, it performs the processing in step S22 and the subsequent steps S3a and beyond. If the control unit 2 determines that there is no next step, it removes the substrate W in step S23 and terminates the process.

[0098] As described above, in the first cycle, during the stabilization step, a first gas containing a first alternative gas is supplied into the plasma processing chamber 10, and the pressure inside the plasma processing chamber 10 is controlled to a first pressure value P1. During the transition step, the gas supplied into the plasma processing chamber 10 is switched from the first gas to the second gas, and a second gas containing a first specific gas is supplied into the plasma processing chamber 10, and the pressure inside the plasma processing chamber 10 is controlled to a second pressure value P2. During the processing step, RF power is supplied from the power supply 31 to generate a plasma of the second gas containing the first specific gas inside the plasma processing chamber 10, and a desired plasma treatment (e.g., etching) is performed on the substrate W.

[0099] Thus, in the first embodiment of the plasma treatment method, plasma treatment can be performed on the substrate W using plasma generated from a second gas containing a first specific gas. Furthermore, in the stabilization step, the amount of the first specific gas used can be reduced by supplying a first gas containing a first substitute gas into the plasma treatment chamber 10 and controlling the pressure inside the plasma treatment chamber 10. The first specific gas is, for example, GH gas. By reducing the amount of GH gas used, environmentally conscious processing of the substrate W can be performed.

[0100] Furthermore, the first pressure value P1 and the second pressure value P2 are approximately equal. This allows the pressure inside the plasma processing chamber 10 to be quickly controlled to the second pressure value P2, which is the pressure in the processing step, after switching the gas supplied to the plasma processing chamber 10 from the first gas to the second gas during the transition step. Thus, the amount of the first specific gas used during the transition step can be reduced.

[0101] Furthermore, it is more preferable that the first pressure value P1 and the second pressure value P2 are equal. This allows for a further reduction in the amount of the first specific gas used in the transition step.

[0102] Furthermore, although it has been explained that the flow rate of the first substitute gas contained in the first gas and the flow rate of the first specific gas contained in the second gas are the same, and the total flow rate of the first gas and the total flow rate of the second gas are the same (total flow rate S1), it is not limited to this. Also, the flow rate of the first substitute gas contained in the first gas and the flow rate of the first specific gas contained in the second gas may be approximately the same, and the total flow rate of the first gas and the total flow rate of the second gas may be approximately the same. For example, the ratio of the total flow rate S12 of the second gas to the total flow rate S11 of the first gas may be in the range of 0.95 to 1.05 (0.95 ≤ S12 / S11 ≤ 1.05).

[0103] Furthermore, in the second cycle, during the stabilization step, a third gas containing a second alternative gas is supplied into the plasma processing chamber 10, and the pressure inside the plasma processing chamber 10 is controlled to a third pressure value P3. During the transition step, the gas supplied into the plasma processing chamber 10 is switched from the third gas to the fourth gas, and a fourth gas containing a second specific gas is supplied into the plasma processing chamber 10, and the pressure inside the plasma processing chamber 10 is controlled to a fourth pressure value P4. During the processing step, RF power is supplied from the power supply 31 to generate a plasma of the fourth gas containing the second specific gas inside the plasma processing chamber 10, and the substrate W is subjected to a desired plasma treatment (e.g., etching).

[0104] Thus, in the first embodiment of the plasma treatment method, plasma treatment can be performed on the substrate W using plasma generated from a fourth gas containing a second specific gas. Furthermore, in the stabilization step, the amount of the second specific gas used can be reduced by supplying a third gas containing a second substitute gas into the plasma treatment chamber 10 and controlling the pressure inside the plasma treatment chamber 10. The second specific gas is, for example, Xe gas. This reduces the amount of Xe gas used, which is difficult to obtain and expensive.

[0105] Furthermore, the third pressure value P3 and the fourth pressure value P4 are approximately equal. This allows the pressure inside the plasma processing chamber 10 to be quickly controlled to the fourth pressure value P4, which is the pressure in the processing step, after switching the gas supplied to the plasma processing chamber 10 from the third gas to the fourth gas during the transition step. Thus, the amount of the second specific gas used during the transition step can be reduced.

[0106] Furthermore, it is more preferable that the third pressure value P3 and the fourth pressure value P4 are equal. This allows for a further reduction in the amount of the second specific gas used in the transition step.

[0107] Furthermore, although it has been explained that the flow rate of the second substitute gas contained in the third gas and the flow rate of the second specified gas contained in the fourth gas are the same, and the total flow rate of the third gas and the total flow rate of the fourth gas are the same (total flow rate S2), it is not limited to this. Also, the flow rate of the second substitute gas contained in the third gas and the flow rate of the second specified gas contained in the fourth gas may be approximately the same, and the total flow rate of the third gas and the total flow rate of the fourth gas may be approximately the same. For example, the ratio of the total flow rate S22 of the fourth gas to the total flow rate S21 of the third gas may be in the range of 0.95 to 1.05 (0.95 ≤ S22 / S21 ≤ 1.05).

[0108] [Examples of effects] In the first embodiment, the control unit 2 executes the following process.

[0109] The aforementioned process, (A) The step of preparing a substrate in the processing chamber, (B) The step of supplying the first gas from the gas supply unit into the processing chamber, (C) A step of supplying a second gas containing a gas different from the first gas into the processing chamber from the gas supply unit, (D) The step of supplying RF power from the RF power supply, generating plasma from the second gas, and processing the substrate with the plasma, (E) Steps (B) to (D) above are performed in this order.

[0110] (B) is a stabilization step, (C) is a transition step, and (D) is a processing step, where the total flow rate of the first gas is equal to the total flow rate of the second gas. The time for supplying the first gas in (B) is controlled to be longer than the time it takes for the pressure in the plasma processing chamber 10 to reach the pressure in the plasma processing chamber 10 controlled in (D).

[0111] In the second embodiment, the control unit 2 further executes the following process.

[0112] The above process further, (F) A step of supplying a third gas from the gas supply unit into the processing chamber, (G) A step of supplying a fourth gas containing a gas different from the third gas from the gas supply unit into the processing chamber, (H) The step of supplying RF power from the RF power supply, generating plasma from the fourth gas, and processing the substrate with the plasma, (I) After (E) above, steps (F) to (H) above are performed in this order.

[0113] (F) is a stabilization step, (G) is a transition step, and (H) is a processing step, where the total flow rate of the third gas is equal to the total flow rate of the fourth gas. The fourth gas may contain a different gas from the second gas. The time for supplying the third gas in (F) is controlled to be longer than the time it takes for the pressure in the plasma processing chamber 10 to reach the pressure in the plasma processing chamber 10 controlled in (H).

[0114] In the first embodiment, the stabilization step, transition step, and processing step are performed in that order, and in these steps, the total flow rate of the first gas and the total flow rate of the second gas supplied to the plasma processing chamber 10 are equal. Therefore, in the stabilization step, the pressure inside the plasma processing chamber 10 is stabilized to a set value, and then the pressure inside the plasma processing chamber 10 is maintained at the set value until the processing step. In addition, a substitute gas for GH gas is used in the stabilization step. Furthermore, a transition step is provided between the stabilization step and the processing step, and a second gas, which is a GH gas instead of a substitute gas, is supplied to adjust the atmosphere inside the plasma processing chamber 10 to process conditions for substrate processing, and then the plasma processing of the substrate W is performed in the processing step. This makes it possible to reduce the amount of GH gas used without affecting the plasma processing of the substrate W, and to perform processing of the substrate W while considering the environment.

[0115] In the second embodiment, CO gas is used as the first alternative gas to GH gas in the stabilization step, and Ar gas is used as the second alternative gas to Xe gas. Then, in the transition step, the alternative gas is switched to either GH gas or Xe gas to adjust the atmosphere in the plasma processing chamber 10 to process conditions for substrate processing. After that, the substrate W is processed in the processing step. This makes it possible to reduce the amount of GH gas and Xe gas used without affecting the processing of the substrate W, and enables processing of the substrate W while considering the environment and cost.

[0116] [others] As explained above, the first gas may be a gas that does not contain a gas having at least one element selected from C, F, or Xe (first specified gas). The second gas contains the first specified gas having at least one element selected from C, F, or Xe, and the first gas may contain a gas in which the first specified gas contained in the second gas is replaced with another gas.

[0117] Other gases included in the first gas are gases other than the first specified gas included in the second gas, and may include gases included in the second gas. This allows for smoother gas switching during the transition step.

[0118] Other gases included in the first gas may include inert gases other than Xe gas. Other gases may be gases other than the specific gas included in the second gas, and may not be gases included in the second gas. The first gas contains one or more gases, and the second gas contains one or more gases. The first gas and the second gas may contain the same gas, or they may all be different gases.

[0119] The third gas may be a gas that does not contain the second specified gas, which has at least one element selected from C, F, or Xe. The fourth gas may contain the second specified gas, which has at least one element selected from C, F, or Xe, and the third gas may contain a gas in which the second specified gas contained in the fourth gas is replaced with another gas.

[0120] Other gases included in the third gas are gases other than the second specified gas included in the fourth gas, and may include gases included in the fourth gas. This allows for smoother gas switching during the transition step.

[0121] Other gases included in the third gas may include inert gases other than Xe gas. Other gases may be gases other than the specific gas included in the fourth gas, and may not be gases included in the fourth gas. The third gas includes one or more gases, and the fourth gas includes one or more gases. The third gas and the fourth gas may contain the same gas, or they may all be different gases.

[0122] GH gases include, for example, CxFy gases such as CF4 gas, CHF3 gas, C4F6 gas, C4F8 gas, CH2F2 gas, C3F8 gas, CH3F gas, C2F6 gas, NF3 gas, SF6 gas, and other F-containing gases. However, GH gases are not limited to the above gases, as long as they contain at least one element selected from C and F.

[0123] In the stabilization step, the pressure regulating valve and vacuum pump of the exhaust system 40 are mainly controlled to stabilize the pressure inside the chamber. In the transition step, the mass flow controller or pressure-controlled flow controller of the gas supply unit 20 are mainly controlled to replace the gas.

[0124] It should be noted that the present invention is not limited to the configurations shown in the above embodiments, including combinations with other elements. These points can be modified without departing from the spirit of the invention and can be appropriately determined according to their application. Furthermore, the matters described in the multiple embodiments can be combined with other configurations as long as they do not contradict each other.

[0125] For example, the treatment of the substrate W is not limited to etching, but may also be film deposition, sputtering, or the like.

[0126] Furthermore, the plasma processing apparatus is not limited to a capacitively coupled plasma processing apparatus, but may be applied to other plasma processing apparatuses. For example, an inductively coupled plasma (ICP) processing apparatus may be used instead of a capacitively coupled plasma processing apparatus. In this case, the inductively coupled plasma processing apparatus includes an antenna and a lower electrode. The lower electrode is located within the substrate support, and the antenna is located above or above the chamber. The RF generator is coupled to the antenna, and the DC generator is coupled to the lower electrode. Therefore, the RF generator is coupled to the upper electrode of the capacitively coupled plasma apparatus or to the antenna of the inductively coupled plasma apparatus. That is, the RF generator is coupled to the plasma processing chamber 10.

[0127] The embodiments disclosed above include, for example, the following aspects: (Note 1) Processing chamber and Gas supply department, RF power supply and A plasma processing apparatus including a control unit, The control unit controls each part of the plasma processing apparatus, (A) The step of preparing a substrate in the processing chamber, (B) A step of supplying a first gas into the processing chamber and controlling the pressure inside the processing chamber to a first pressure value within a first pressure range, (C) A step of switching the gas supplied into the processing chamber from the first gas to the second gas, wherein the first gas has a lower degree of environmental impact than the second gas. (D) A step of supplying the second gas into the processing chamber and controlling the pressure inside the processing chamber to a second pressure value within the first pressure range, (E) The step of supplying RF power from the RF power supply, generating plasma from the second gas, and processing the substrate with the plasma, A plasma processing apparatus configured to perform a process. (Note 2) The first pressure range is a pressure range in which plasma can be stably generated within the processing chamber. The plasma processing apparatus described in Appendix 1. (Note 3) The ratio of the second pressure value to the first pressure value is within the range of 0.95 to 1.05. A plasma processing apparatus as described in Appendix 1 or Appendix 2. (Note 4) The second pressure value is equal to the first pressure value. A plasma processing apparatus as described in any of Appendix 1 to Appendix 3. (Note 5) The total flow rate of the first gas and the total flow rate of the second gas are equal. A plasma processing apparatus as described in any of Appendix 1 to Appendix 4. (Note 6) The second gas includes a specific gas, The first gas does not include the specified gas, but includes an alternative gas. A plasma processing apparatus as described in any of Appendix 1 to Appendix 5. (Note 7) The specified gas includes a gas having at least one element selected from C or F. The plasma processing apparatus described in Appendix 6. (Note 8) The aforementioned alternative gas is a gas with a lower global warming potential than the aforementioned specific gas. A plasma processing apparatus as described in Appendix 6 or Appendix 7. (Note 9) The substitute gas is a gas other than the specified gas among the gases contained in the second gas. A plasma processing apparatus as described in Appendix 6 or Appendix 7. (Note 10) The processing of the substrate is an etching process. The plasma processing apparatus described in Appendix 1. (Note 11) The control unit controls each part of the plasma processing apparatus, (F) A step of supplying a third gas into the processing chamber and controlling the pressure inside the processing chamber to a third pressure value within the second pressure range, (G) A step of switching the gas supplied into the processing chamber from the third gas to the fourth gas, wherein the fourth gas is a more expensive gas than the third gas. (H) A step of supplying the fourth gas into the processing chamber and controlling the pressure inside the processing chamber to a fourth pressure value within the second pressure range, (I) The steps of supplying RF power from the RF power supply, generating plasma from the fourth gas, and processing the substrate with the plasma, further comprising: Configured to perform the process, A plasma processing apparatus as described in any of Appendix 1 to Appendix 10. (Note 12) A plasma processing method performed using a plasma processing apparatus comprising a processing chamber, a gas supply unit, and an RF power supply, (A) The step of preparing a substrate in the processing chamber, (B) A step of supplying a first gas into the processing chamber and controlling the pressure inside the processing chamber to a first pressure value within a first pressure range, (C) A step of switching the gas supplied into the processing chamber from the first gas to the second gas, wherein the first gas has a lower degree of environmental impact than the second gas. (D) A step of supplying the second gas into the processing chamber and controlling the pressure inside the processing chamber to a second pressure value within the first pressure range, (E) The step of supplying RF power from the RF power supply, generating plasma from the second gas, and processing the substrate with the plasma, Plasma treatment method. [Explanation of symbols]

[0128] 1. Plasma processing equipment 2 Control Unit 2a Computer 2a1 Processing Unit 2a2 Storage section 2a3 communication interface 10 Plasma processing chamber (processing chamber) 11. Substrate support section 13 Shower head 21 Gas Source 20 Gas Supply Department 30 Power Systems 31 Power supply (RF power supply) 40 Exhaust System 111 Main body 112 Ring Assembly

Claims

1. Processing chamber and Gas supply department, RF power supply and A plasma processing apparatus including a control unit, The control unit controls each part of the plasma processing apparatus, (A) The step of preparing the substrate in the processing chamber, (B) A step of supplying a first gas into the processing chamber and controlling the pressure inside the processing chamber to a first pressure value within the first pressure range, (C) A step of switching the gas supplied into the processing chamber from the first gas to the second gas, wherein the first gas has a lower degree of environmental impact than the second gas. (D) A step of supplying the second gas into the processing chamber and controlling the pressure inside the processing chamber to a second pressure value within the first pressure range, (E) The step of supplying RF power from the RF power supply, generating plasma from the second gas, and processing the substrate with the plasma, A plasma processing apparatus configured to perform a process.

2. The first pressure range is a pressure range in which plasma can be stably generated within the processing chamber. The plasma processing apparatus according to claim 1.

3. The ratio of the second pressure value to the first pressure value is within the range of 0.95 to 1.

05. The plasma processing apparatus according to claim 1.

4. The second pressure value is equal to the first pressure value. The plasma processing apparatus according to claim 1.

5. The total flow rate of the first gas and the total flow rate of the second gas are equal. The plasma processing apparatus according to claim 1.

6. The second gas includes a specific gas, The first gas does not include the specified gas, but includes an alternative gas. The plasma processing apparatus according to claim 1.

7. The specified gas includes a gas having at least one element selected from C or F. The plasma processing apparatus according to claim 6.

8. The aforementioned alternative gas is a gas with a lower global warming potential than the aforementioned specific gas. The plasma processing apparatus according to claim 6.

9. The substitute gas is a gas other than the specified gas among the gases contained in the second gas. The plasma processing apparatus according to claim 6.

10. The processing of the substrate is an etching process. The plasma processing apparatus according to claim 1.

11. The control unit controls each part of the plasma processing apparatus, (F) A step of supplying a third gas into the processing chamber and controlling the pressure inside the processing chamber to a third pressure value within the second pressure range, (G) A step of switching the gas supplied into the processing chamber from the third gas to the fourth gas, wherein the fourth gas is a more expensive gas than the third gas. (H) A step of supplying the fourth gas into the processing chamber and controlling the pressure inside the processing chamber to a fourth pressure value within the second pressure range, (I) The steps of supplying RF power from the RF power supply, generating plasma from the fourth gas, and processing the substrate with the plasma, further comprising: Configured to perform the process, The plasma processing apparatus according to claim 1.

12. A plasma processing method performed using a plasma processing apparatus including a processing chamber, a gas supply unit, and an RF power supply, (A) The step of preparing the substrate in the processing chamber, (B) A step of supplying a first gas into the processing chamber and controlling the pressure inside the processing chamber to a first pressure value within the first pressure range, (C) A step of switching the gas supplied into the processing chamber from the first gas to the second gas, wherein the first gas has a lower degree of environmental impact than the second gas. (D) A step of supplying the second gas into the processing chamber and controlling the pressure inside the processing chamber to a second pressure value within the first pressure range, (E) The step of supplying RF power from the RF power supply, generating plasma from the second gas, and processing the substrate with the plasma, Plasma treatment method.

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