Plasma treatment device and plasma treatment method

Abstract

The disclosed plasma processing apparatus comprises a first baffle plate and a second baffle plate. The first baffle plate and the second baffle plate are disposed between a processing space and an exhaust space within a chamber. The second baffle plate is installed downstream of the first baffle plate, where gas flows within the chamber. During at least a portion of the waveform period of the electric bias energy periodically applied to a substrate support within the chamber, the value of the voltage applied to the second baffle plate is higher than the value of the voltage applied to the first baffle plate.

Description

Technology Field

[0001] An exemplary embodiment of the present disclosure relates to a plasma treatment apparatus and a plasma treatment method. Background Technology

[0002] A plasma processing device is used for plasma processing of a substrate. The plasma processing device comprises a chamber, a substrate support, and a baffle plate. The substrate support is installed within the chamber. The baffle plate is installed between the substrate support and the side wall of the chamber. The baffle plate is interposed between the processing space and the exhaust space and provides a plurality of through holes. Prior art literature

[0003] Japanese Patent Application Publication No. 2010-3958 The problem to be solved

[0004] The present disclosure provides a technique for suppressing the diffusion of charged particles from a processing space within a chamber to an exhaust space within a chamber. means of solving the problem

[0005] In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus comprises a chamber, a substrate support, a plasma generating unit, a bias power source, a first baffle plate and a second baffle plate, a first power source and a second power source. The substrate support is installed within the chamber. The plasma generating unit is configured to generate plasma from a gas within the chamber. The bias power source is configured to periodically supply electrical bias energy having a waveform period to the substrate support. The first baffle plate and the second baffle plate are disposed within the chamber. The first power source is electrically connected to the first baffle plate. The second power source is electrically connected to the second baffle plate. The first baffle plate is disposed between the second baffle plate and the processing space within the chamber where a substrate disposed on the substrate support is processed therein. The second baffle plate is disposed between the first baffle plate and the exhaust space within the chamber to which an exhaust system is connected. For at least a portion of the waveform period, the value of the voltage applied to the second baffle plate by the second power source is higher than the value of the voltage applied to the first baffle plate by the first power source. Effects of the invention

[0006] According to one exemplary embodiment, a technique is provided to suppress the diffusion of charged particles from a processing space within a chamber to an exhaust space within a chamber. Brief explanation of the drawing

[0007] Figure 1 is a diagram illustrating an example of the configuration of a plasma processing system. Figure 2 is a diagram illustrating an example of the configuration of a capacitance-coupled plasma processing device. Figure 3 is a diagram showing an example of the connection of the first power source and the second power source. Figure 4 is a diagram showing another example of a first power source and a second power source. Figure 5 is a diagram showing another example of a first power source and a second power source. FIGS. 6(a), FIGS. 6(b), and FIGS. 6(c) are each timing charts related to a plasma processing apparatus according to one exemplary embodiment. FIGS. 7(a), FIGS. 7(b), FIGS. 7(c) and FIGS. 7(d) are each timing charts related to a plasma processing apparatus according to one exemplary embodiment. FIGS. 8(a) and FIGS. 8(b) are timing charts related to a plasma processing apparatus according to one exemplary embodiment. FIG. 9 is a flowchart of a plasma treatment method according to one exemplary embodiment. Specific details for implementing the invention

[0008] Various exemplary embodiments are described below.

[0009] In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus comprises a chamber, a substrate support, a plasma generating unit, a bias power source, a first baffle plate and a second baffle plate, a first power source and a second power source. The substrate support is installed within the chamber. The plasma generating unit is configured to generate plasma from a gas within the chamber. The bias power source is configured to periodically supply electrical bias energy having a waveform period to the substrate support. The first baffle plate and the second baffle plate are disposed within the chamber. The first power source is electrically connected to the first baffle plate. The second power source is electrically connected to the second baffle plate. The first baffle plate is disposed between the second baffle plate and the processing space within the chamber where a substrate disposed on the substrate support is processed therein. The second baffle plate is disposed between the first baffle plate and the exhaust space within the chamber to which an exhaust system is connected. For at least a portion of the waveform period, the value of the voltage applied to the second baffle plate by the second power source is higher than the value of the voltage applied to the first baffle plate by the first power source.

[0010] When the potential of the second baffle plate is higher than the potential of the first baffle plate, the flow of cations from the plasma in the processing space from the first baffle plate toward the second baffle plate is suppressed. Accordingly, according to the above embodiment, it is possible to suppress the diffusion of charged particles from the processing space in the chamber to the exhaust space in the chamber.

[0011] In one exemplary embodiment, the value of the voltage applied to the second baffle plate by the second power source may be higher than the value of the voltage applied to the first baffle plate by the first power source in all waveform cycles.

[0012] In one exemplary embodiment, the waveform period may include a positive phase period in which the potential of the substrate is higher than the average potential of the substrate within the waveform period and a negative phase period in which the potential of the substrate is lower than the average potential. During the negative phase period, the value of the voltage applied to the second baffle plate by the second power source may be higher than the value of the voltage applied to the first baffle plate by the first power source.

[0013] In one exemplary embodiment, the value of the voltage applied to the second baffle plate by the second power source may be constant.

[0014] In one exemplary embodiment, the waveform period may include a positive phase period in which the potential of the substrate is higher than the average potential of the substrate within the waveform period and a negative phase period in which the potential of the substrate is lower than the average potential. During the positive phase period, the value of the voltage applied to the second baffle plate by the second power source may be higher than the value of the voltage applied to the first baffle plate by the first power source.

[0015] In one exemplary embodiment, the value of the voltage applied to the first baffle plate by the first power source may be constant.

[0016] In one exemplary embodiment, the chamber may be grounded. In a waveform period, the potential of the second baffle plate may be higher than the potential of the chamber.

[0017] In one exemplary embodiment, the first baffle plate and the second baffle plate may extend between the outer circumference of the substrate support and the side wall of the chamber.

[0018] In one exemplary embodiment, at least one of the first baffle plate and the second baffle plate may be movable.

[0019] In one exemplary embodiment, the electric bias energy may be a bias high-frequency power having a frequency that is the inverse of the time length of the waveform period, or a pulse of voltage applied to a substrate support at time intervals equal to the time length of the waveform period.

[0020] In another exemplary embodiment, a plasma treatment method is provided. The plasma treatment method includes a process of generating plasma within a chamber of a plasma treatment apparatus. The plasma treatment method further includes a process of supplying electrical bias energy having a waveform period to a substrate support disposed within the chamber. The plasma treatment method further includes a process of applying voltage to each of a first baffle plate and a second baffle plate disposed within the chamber. The first baffle plate is disposed between the second baffle plate and a processing space within the chamber where a substrate disposed on the substrate support is processed therein. The second baffle plate is disposed between the first baffle plate and an exhaust space within the chamber to which an exhaust system is connected. For at least a portion of the waveform period, the value of the voltage applied to the second baffle plate is higher than the value of the voltage applied to the first baffle plate.

[0021] Various exemplary embodiments are described in detail below with reference to the drawings. Additionally, identical or similar elements in each drawing are denoted by the same reference numerals.

[0022] FIG. 1 is a drawing for explaining an example configuration 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 unit (11), and a plasma generation unit (12). The plasma processing chamber (10) has a plasma processing space. In addition, the plasma processing chamber (10) has at least one gas supply port for supplying at least one processing gas to the plasma processing space and at least one gas discharge port for discharging gas from the plasma processing space. The gas supply port is connected to a gas supply unit (20) described later, and the gas discharge port is connected to an exhaust system (40) described later. The substrate support unit (11) is disposed within the plasma processing space and has a substrate support surface for supporting a substrate.

[0023] 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 plasma (ECR), a helicon wave excited plasma (HWP), or a surface wave plasma (SWP).

[0024] The control unit (2) processes commands executable by a computer to execute various processes described in the present disclosure on the plasma processing device (1). The control unit (2) may be configured to control each element of the plasma processing device (1) to execute various processes described herein. In one embodiment, part or all of the control unit (2) may be included in the plasma processing device (1). The control unit (2) may include a processing unit (2a1), a memory unit (2a2), and a communication interface (2a3). The control unit (2) is realized, for example, by a computer (2a). The processing unit (2a1) may be configured to perform various control operations by reading a program from the memory unit (2a2) and executing the read program. This program may be stored in the memory unit (2a2) in advance, or may be acquired through a medium when necessary. The acquired program is stored in the memory unit (2a2) and is read from the memory unit (2a2) and executed by the processing unit (2a1). The medium may be various storage media readable by a computer (2a) or a communication line connected to a communication interface (2a3). The processing unit (2a1) may be a CPU (Central Processing Unit). The storage 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 each element of the plasma processing device (1) through a communication line such as a LAN (Local Area Network).

[0025] Below, an example of the configuration of a capacitance-coupled plasma processing device is described as an example of a plasma processing device (1). FIG. 2 is a drawing for explaining an example of the configuration of a capacitance-coupled plasma processing device.

[0026] A capacitively coupled plasma processing device (1) comprises a plasma processing chamber (10), a gas supply unit (20), and an exhaust system (40). Additionally, the plasma processing device (1) comprises a substrate support (11) and a gas introduction unit. The gas introduction unit is configured to introduce at least one processing gas into the plasma processing chamber (10). The gas introduction unit includes a shower head (13). The substrate support (11) is positioned within the plasma processing chamber (10). The shower head (13) is positioned above the substrate support (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 an internal space (10s) defined by the shower head (13), the side wall (10a) of the plasma processing chamber (10), and the substrate support (11). The internal space (10s) includes a processing space (10sp) and an exhaust space (10se). The plasma processing chamber (10) is grounded. The substrate support (11) is electrically insulated from the housing of the plasma processing chamber (10).

[0027] 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 a substrate (W) and a ring-shaped region (111b) for supporting a ring assembly (112). A wafer is an example of a substrate (W). The ring-shaped region (111b) of the main body portion (111) surrounds the central region (111a) of the main body portion (111) when viewed in a plane. A substrate (W) is placed on the central region (111a) of the main body portion (111), and a ring assembly (112) is placed on the ring-shaped region (111b) of the main body portion (111) to surround the substrate (W) on the central region (111a) of the main body portion (111). Accordingly, the central region (111a) is also referred to as a substrate support surface for supporting the substrate (W), and the ring-shaped region (111b) is also referred to as a ring support surface for supporting the ring assembly (112).

[0028] In one embodiment, the main body (111) includes a base (1110) and an electrostatic chuck (1111). The base (1110) includes a conductive member. The electrostatic chuck (1111) is disposed on the base (1110). The electrostatic chuck (1111) includes a ceramic member (1111a) and an electrostatic electrode (1111b) disposed within the ceramic member (1111a). The ceramic member (1111a) has a central region (111a). In one embodiment, the ceramic member (1111a) also has an annular region (111b). Additionally, another member surrounding the electrostatic chuck (1111), such as an annular electrostatic chuck or an annular insulating member, may have an annular region (111b). In this case, a ring assembly (112) may be disposed on the annular electrostatic chuck or an annular insulating member, or may be disposed on both the electrostatic chuck (1111) and the annular insulating member.

[0029] 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 rings are formed of a conductive material or an insulating material, and the cover ring is formed of an insulating material.

[0030] Additionally, the substrate support (11) may include a temperature control module configured to control at least one of the electrostatic chuck (1111), ring assembly (112), and substrate 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 disposed within the ceramic member (1111a) of the electrostatic chuck (1111). Additionally, the substrate support (11) may include a heat transfer gas supply unit configured to supply a heat transfer gas into the gap between the back surface of the substrate (W) and the central region (111a).

[0031] The shower head (13) is configured to introduce at least one processing gas from the gas supply unit (20) into the processing space (10sp). The shower head (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 processing space (10sp) from the plurality of gas inlet ports (13c). Additionally, the shower head (13) includes at least one upper electrode. Furthermore, the gas inlet port may include one or more side gas injectors (SGI) mounted in one or more openings formed in the side wall (10a) in conjunction with the shower head (13).

[0032] 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 each corresponding gas source (21) to the shower head (13) through each corresponding flow controller (22). Each flow controller (22) may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, 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.

[0033] The exhaust system (40) may be connected, for example, to a gas outlet (10e) installed at the bottom of the plasma processing chamber (10). The gas outlet (10e) is connected to an exhaust space (10se). The exhaust system (40) is connected to a processing space (10sp) through the exhaust space (10se). The exhaust system (40) may include a pressure regulating valve and a vacuum pump. The pressure within the internal space (10s) is regulated by the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0034] The plasma processing device (1) further comprises a high-frequency power supply (31) and a bias power supply (32). The high-frequency power supply (31) constitutes a plasma generating unit (12) of one embodiment. The high-frequency power supply (31) is configured to generate source high-frequency power (RF). The source high-frequency power (RF) is a source frequency (f RF It has the source frequency (f). RFThe frequency may be in the range of 10 MHz to 150 MHz. The high-frequency power supply (31) is electrically connected to the high-frequency electrode through a matching device (33) and configured to supply source high-frequency power (RF) to the high-frequency electrode. The high-frequency electrode may be a conductive member of the base (1110), at least one electrode installed within the ceramic member (1111a), or an upper electrode. When source high-frequency power (RF) is supplied to the high-frequency electrode, plasma is generated from the gas in the chamber (10).

[0035] The matching unit (33) has a variable impedance. The variable impedance of the matching unit (33) is set to reduce reflection from the load of the source high-frequency power (RF). The matching unit (33) can be controlled, for example, by a control unit (2).

[0036] The bias power source (32) is configured to generate electric bias energy (BE). The bias power source (32) is electrically coupled to the substrate support (11). The bias power source (32) is electrically connected to a bias electrode within the substrate support (11) and is configured to supply electric bias energy (BE) to the bias electrode. The bias electrode may be at least one electrode installed within the conductive member or ceramic member (1111a) of the base (1110). When electric bias energy (BE) is supplied to the bias electrode, ions from the plasma are attracted to the substrate (W).

[0037] The electric bias energy (BE) has a bias frequency. The bias frequency is lower than the source frequency. The bias frequency may be a frequency in the range of 100 kHz to 60 MHz. Additionally, the electric bias energy (BE) has a waveform period (CY). The waveform period (CY) has a time length that is the reciprocal of the bias frequency. The electric bias energy (BE) is supplied periodically to the bias electrode at the waveform period (CY) (time interval).

[0038] The electric bias energy (BE) may be a bias high-frequency power having a bias frequency (see FIG. 6(a) and FIG. 7(a)). That is, the electric bias energy (BE) may have a sinusoidal waveform whose frequency is the bias frequency. In this case, the bias power supply (32) is electrically connected to the bias electrode through a matching unit (34). The variable impedance of the matching unit (34) is set to reduce reflection from the load of the bias high-frequency power (LF).

[0039] Alternatively, the electric bias energy (BE) may include voltage pulses (see FIG. 8(a)). Voltage pulses are applied to the bias electrode within a waveform period (CY). Voltage pulses are applied periodically to the bias electrode at time intervals equal to the time length of the waveform period (CY). The waveform of the voltage pulses may be a rectangular wave, a triangular wave, or any other waveform. The polarity of the voltage pulses is set so as to generate a potential difference between the substrate (W) and the plasma to attract ions from the plasma to the substrate (W). In one example, the voltage pulses may be negative voltage pulses. Furthermore, when the electric bias energy (BE) is a voltage pulse, the plasma processing device (1) does not need to be equipped with a matching device (34).

[0040] The plasma processing device (1) further comprises a first baffle plate (41) and a second baffle plate (42). The first baffle plate (41) and the second baffle plate (42) are installed within the chamber (10). The first baffle plate (41) is positioned between the processing space (10sp) and the second baffle plate (42). The processing space (10sp) is a space within the chamber (10) where a substrate (W) placed on the substrate support (11) is processed therein. The second baffle plate (42) is positioned between the exhaust space (10se) and the first baffle plate (41). The exhaust space (10se) is a space within the chamber (10) to which the exhaust system (40) is connected. That is, the first baffle plate (41) is installed upstream of the second baffle plate (42) in the flow of gas within the chamber (10). The second baffle plate (42) is installed downstream of the first baffle plate (41).

[0041] In one embodiment, as shown in FIG. 2, the first baffle plate (41) and the second baffle plate (42) extend between the outer circumference of the substrate support (11) and the side wall of the chamber (10), and extend circumferentially around the substrate support (11). The outer edges of each of the first baffle plate (41) and the second baffle plate (42) are supported by an insulating member (43). The inner edges of each of the first baffle plate (41) and the second baffle plate (42) are supported by an insulating member of the substrate support (11).

[0042] In one embodiment, at least one of the first baffle plate (41) and the second baffle plate (42) may be movable. In this embodiment, the plasma processing device (1) further comprises a driving unit (44). The driving unit (44) moves at least one of the first baffle plate (41) and the second baffle plate (42) to change the relative position of the first baffle plate (41) and the second baffle plate (42). The driving unit (44) may also move at least one of the first baffle plate (41) and the second baffle plate (42) to change the distance between the first baffle plate (41) and the second baffle plate (42). The driving unit (44) may also rotate at least one of the first baffle plate (41) and the second baffle plate (42) around a central axis. The driving unit (44) may include a motor or a hydraulic or pneumatic cylinder.

[0043] The plasma processing device (1) further comprises a first power source (51) and a second power source (52). The first power source (51) and the second power source (52) are, for example, variable DC power sources. The first power source (51) is electrically connected to the first baffle plate (41). The second power source (52) is electrically connected to the second baffle plate (42). Specifically, one pole (e.g., negative pole) of the first power source (51) is electrically connected to the first baffle plate (41) through a filter (51f). One pole (e.g. negative pole) of the second power source (52) is electrically connected to the second baffle plate (42) through a filter (52f). Each of the filter (51f) and the filter (52f) is an electric filter that blocks or reduces high-frequency power. The other pole (e.g. positive pole) of each of the first power source (51) and the second power source (52) is connected to ground.

[0044] Refer to FIG. 3 here. FIG. 3 is a diagram showing an example of connection between a first power source and a second power source. As shown in FIG. 3, the other pole (e.g., positive pole) of the second power source (52) may be connected to one pole (e.g., negative pole) of the first power source (51).

[0045] Refer to FIGS. 4 and FIGS. 5 below. FIGS. 4 and FIGS. 5 are drawings illustrating another example of a first power source and a second power source. In the example shown in FIGS. 4 and FIGS. 5, the first power source (51) includes a power source (511) and a power source (512). The second power source (52) includes a power source (521) and a power source (522). The power sources (511), (512), (521), and (522) are, for example, variable DC power sources. The negative terminal of the power source (511) is connected to the output (51o) of the first power source (51) through a switch. The positive terminal of the power source (511) is connected to ground. The positive terminal of the power source (512) is connected to the output (51o) of the first power source (51) through a switch. The negative terminal of the power source (512) is connected to ground. The output (51o) of the first power source (51) is connected to the first baffle plate (41) through a filter (51f). The negative terminal of the power source (521) is connected to the output (52o) of the second power source (52) through a switch. The positive terminal of the power source (522) is connected to the output (52o) of the second power source (52) through a switch. The output (52o) of the second power source (52) is connected to the second baffle plate (42) through a filter (52f). In the example shown in FIG. 4, the positive terminal of the power source (521) and the negative terminal of the power source (512) are connected to ground. In the example shown in FIG. 5, the positive terminal of the power source (521) and the negative terminal of the power source (522) are connected to the output (51o) of the first power source (51). In the example shown in FIGS. 4 and 5, the first power source (51) and the second power source (52) are configured as power sources capable of switching the polarity of the output voltage. Additionally, each of the first power source (51) and the second power source (52) may be a bipolar power source capable of continuously outputting both positive and negative voltages.

[0046] Hereinafter, together with FIG. 1, FIG. 6(a), FIG. 6(b), FIG. 6(c), FIG. 7(a), FIG. 7(b), FIG. 7(c), FIG. 7(d), FIG. 8(a) and FIG. 8(b). These figures are timing charts related to a plasma processing apparatus according to an exemplary embodiment. Specifically, FIG. 6(a), FIG. 7(a), and FIG. 8(a) each represent an exemplary timing chart of electric bias energy. FIG. 6(b), FIG. 6(c), FIG. 7(b), FIG. 7(c), and FIG. 7(d) each represent an exemplary timing chart of the potential of the first electrode (P41), the potential of the second electrode (P42), and the plasma potential (PP). FIG. 8(b) represents an exemplary timing chart of the potential of the first electrode (P41) and the potential of the second electrode (P42).

[0047] As shown in FIGS. 6(a), FIGS. 7(a), and FIGS. 8(a), the waveform period (CY) includes a positive phase period (PI) and a negative phase period (NI). During the positive phase period (PI), the potential of the substrate (W) is higher than the average potential of the substrate (W) within the waveform period (CY). During the negative phase period (NI), the potential of the substrate (W) is lower than the average potential of the substrate (W) within the waveform period (CY). The potential of the substrate (W) changes mainly according to the electric bias energy (BE).

[0048] The plasma potential (PP) varies depending on the electric bias energy (BE) or the potential of the substrate (W). During the positive phase period (PI), the plasma potential (PP) is high, and during the negative phase period (NI), the plasma potential (PP) is low.

[0049] For at least a portion of the waveform period (CY), the value of the voltage applied to the second baffle plate (42) by the second power source (52) is higher than the value of the voltage applied to the first baffle plate (41) by the first power source (51). Therefore, as illustrated, for at least a portion of the waveform period (CY), the potential (P42) of the second baffle plate (42) is higher than the potential (P41) of the first baffle plate (41).

[0050] When the potential (P42) of the second baffle plate (42) is higher than the potential (P41) of the first baffle plate (41), the flow of positive ions from the plasma in the processing space (10sp) from the first baffle plate (41) toward the second baffle plate (42) is suppressed. Therefore, it is possible to suppress the diffusion of charged particles from the processing space (10sp) toward the exhaust space (10se).

[0051] At least one of the voltage applied to the first baffle plate (41) by the first power source (51) and the voltage applied to the second baffle plate (42) by the second power source (52) may have a waveform that follows the waveform of the plasma potential (PP). In this case, at least one of the first power source (51) and the second power source (52) is synchronized with the bias power source (32) by a synchronization signal and outputs a voltage with a waveform that follows the waveform of the plasma potential (PP). Alternatively, the value of one of the voltage applied to the first baffle plate (41) by the first power source (51) and the voltage applied to the second baffle plate (42) by the second power source (52) may be constant, as shown in FIG. 6(b), FIG. 6(c), FIG. 7(d), and FIG. 8(b).

[0052] In one embodiment, as shown in FIG. 6(b) and FIG. 8(b), during the negative phase period (NI), the value of the voltage applied to the second baffle plate (42) by the second power source (52) is higher than the value of the voltage applied to the first baffle plate (41) by the first power source (51). Therefore, during the negative phase period (NI), the potential (P42) of the second baffle plate (42) is higher than the potential (P41) of the first baffle plate (41). During the positive phase period (PI), the value of the voltage applied to the second baffle plate (42) by the second power source (52) is lower than the value of the voltage applied to the first baffle plate (41) by the first power source (51). Therefore, during the positive phase period (PI), the potential (P42) of the second baffle plate (42) is lower than the potential (P41) of the first baffle plate (41). In all waveform periods (CY), the value of the voltage applied to the first baffle plate (41) by the first power source (51) and the value of the voltage applied to the second baffle plate (42) by the second power source (52) are positive values. Therefore, in all waveform periods (CY), the potential (P42) of the second baffle plate (42) is higher than the ground potential of the chamber (10). The voltage applied to the first baffle plate (41) by the first power source (51) has a waveform that follows the waveform of the plasma potential (PP). The value of the voltage applied to the second baffle plate (42) by the second power source (52) is constant.

[0053] In the embodiments shown in FIG. 6(b) and FIG. 8(b), respectively, during the negative phase period (NI), positive ions from the plasma in the processing space (10sp) are suppressed from flowing from the first baffle plate (41) toward the second baffle plate (42). Additionally, during the negative phase period (NI), secondary electrons that can be emitted from the first baffle plate (41) are captured at the second baffle plate (42), so that the secondary electrons flow toward the exhaust space (10se).

[0054] In another embodiment, as shown in FIG. 6(c), at every waveform period (CY), the value of the voltage applied to the second baffle plate (42) by the second power source (52) is higher than the value of the voltage applied to the first baffle plate (41) by the first power source (51). Therefore, at every waveform period (CY), the potential (P42) of the second baffle plate (42) is higher than the potential (P41) of the first baffle plate (41). At every waveform period (CY), the value of the voltage applied to the first baffle plate (41) by the first power source (51) and the value of the voltage applied to the second baffle plate (42) by the second power source (52) are positive values. Therefore, at every waveform period (CY), the potential (P42) of the second baffle plate (42) is higher than the ground potential of the chamber (10). The voltage applied to the first baffle plate (41) by the first power source (51) has a waveform that follows the waveform of the plasma potential (PP). The value of the voltage applied to the second baffle plate (42) by the second power source (52) is constant.

[0055] In the embodiment shown in FIG. 6(c), positive ions from the plasma in the processing space (10sp) are suppressed from flowing from the first baffle plate (41) toward the second baffle plate (42) in all waveform cycles (CY). Additionally, in all waveform cycles (CY), secondary electrons that can be emitted from the first baffle plate (41) are captured at the second baffle plate (42), so that the secondary electrons flow toward the exhaust space (10se).

[0056] In another embodiment, as shown in FIG. 7(b), at every waveform period (CY), the value of the voltage applied to the second baffle plate (42) by the second power source (52) is higher than the value of the voltage applied to the first baffle plate (41) by the first power source (51). Therefore, at every waveform period (CY), the potential (P42) of the second baffle plate (42) is higher than the potential (P41) of the first baffle plate (41). At every waveform period (CY), the value of the voltage applied to the second baffle plate (42) by the second power source (52) is a positive value. Therefore, at every waveform period (CY), the potential (P42) of the second baffle plate (42) is higher than the ground potential of the chamber (10). The value of the voltage applied to the first baffle plate (41) by the first power source (51) is negative during the negative phase period (NI) and positive during the positive phase period (PI). The voltage applied to the first baffle plate (41) by the first power source (51) and the voltage applied to the second baffle plate (42) by the second power source (52) have a waveform that follows the waveform of the plasma potential (PP).

[0057] In the embodiment shown in FIG. 7(b), positive ions from the plasma in the processing space (10sp) are suppressed from flowing from the first baffle plate (41) toward the second baffle plate (42) in all waveform cycles (CY). Additionally, in all waveform cycles (CY), secondary electrons that can be emitted from the first baffle plate (41) are captured at the second baffle plate (42), so that the secondary electrons flow toward the exhaust space (10se).

[0058] In another embodiment, as shown in FIG. 7(c), at every waveform period (CY), the value of the voltage applied to the second baffle plate (42) by the second power source (52) is higher than the value of the voltage applied to the first baffle plate (41) by the first power source (51). Therefore, at every waveform period (CY), the potential (P42) of the second baffle plate (42) is higher than the potential (P41) of the first baffle plate (41). At every waveform period (CY), the value of the voltage applied to the first baffle plate (41) by the first power source (51) and the value of the voltage applied to the second baffle plate (42) by the second power source (52) are positive values. Therefore, at every waveform period (CY), the potential (P42) of the second baffle plate (42) is higher than the ground potential of the chamber (10). The voltage applied to the first baffle plate (41) by the first power source (51) and the voltage applied to the second baffle plate (42) by the second power source (52) have a waveform that follows the waveform of the plasma potential (PP).

[0059] In the embodiment shown in FIG. 7(c), positive ions from the plasma in the processing space (10sp) are suppressed from flowing from the first baffle plate (41) toward the second baffle plate (42) in all waveform cycles (CY). Additionally, in all waveform cycles (CY), secondary electrons that can be emitted from the first baffle plate (41) are captured at the second baffle plate (42), so that the secondary electrons flow toward the exhaust space (10se).

[0060] In another embodiment, as shown in FIG. 7(d), during the positive phase period (PI), the value of the voltage applied to the second baffle plate (42) by the second power source (52) is higher than the value of the voltage applied to the first baffle plate (41) by the first power source (51). Therefore, during the positive phase period (PI), the potential (P42) of the second baffle plate (42) is higher than the potential (P41) of the first baffle plate (41). During the negative phase period (NI), the value of the voltage applied to the second baffle plate (42) by the second power source (52) is lower than the value of the voltage applied to the first baffle plate (41) by the first power source (51). Therefore, during the negative phase period (NI), the potential (P42) of the second baffle plate (42) is lower than the potential (P41) of the first baffle plate (41). In all waveform periods (CY), the value of the voltage applied to the first baffle plate (41) by the first power source (51) and the value of the voltage applied to the second baffle plate (42) by the second power source (52) are positive values. Therefore, in all waveform periods (CY), the potential (P42) of the second baffle plate (42) is higher than the ground potential of the chamber (10). The voltage applied to the second baffle plate (42) by the second power source (52) has a waveform that follows the waveform of the plasma potential (PP). The value of the voltage applied to the first baffle plate (41) by the first power source (51) is constant.

[0061] In the embodiment shown in FIG. 7(d), positive ions from the plasma in the processing space (10sp) are suppressed from flowing from the first baffle plate (41) toward the second baffle plate (42) during the positive phase period (PI). Additionally, during the positive phase period (PI), secondary electrons that can be emitted from the first baffle plate (41) are captured at the second baffle plate (42), so that the secondary electrons flow toward the exhaust space (10se).

[0062] Refer to FIG. 9 below. FIG. 9 is a flowchart of a plasma treatment method according to an exemplary embodiment. The plasma treatment method shown in FIG. 9 (hereinafter referred to as 'method (MT)') can be applied to a plasma treatment apparatus (1). The method (MT) includes process STa to process STc.

[0063] In process STa, plasma is generated within the chamber (10). In process STa, gas from the gas supply unit (20) is supplied to the processing space (10sp). In process STa, the pressure within the chamber (10) is reduced to a specified pressure by the exhaust system (40). In process STa, plasma is generated from the gas within the processing space (10sp) by the plasma generation unit (12). In one embodiment, source high-frequency power (RF) from the high-frequency power source (31) is supplied to the high-frequency electrode.

[0064] Process STb is performed when plasma is generated in process STa. In process STb, electric bias energy (BE) is supplied to the substrate support (11).

[0065] Process STc is performed when electric bias energy (BE) is supplied to the substrate support (11) in process STb. In process STc, voltage is applied to each of the first baffle plate (41) and the second baffle plate (42) as described above. As described above, for at least a portion of the waveform period (CY), the value of the voltage applied to the second baffle plate (42) is higher than the value of the voltage applied to the first baffle plate (41).

[0066] Although various exemplary embodiments have been described above, the invention is not limited to the exemplary embodiments described above, and various additions, omissions, substitutions, and changes may be made. Furthermore, other embodiments may be formed by combining elements of different embodiments.

[0067] For example, the exhaust space (10se) may be installed to the side or above the processing space (10sp).

[0068] From the foregoing description, it will be understood that various embodiments of the present disclosure are described herein for illustrative purposes only and may be modified without departing from the scope and essence of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, and the true scope and essence are defined by the appended claims. Explanation of the symbols

[0069] 1: Plasma processing device, 10: Chamber, 11: Substrate support, 12: Plasma generation unit, 32: Bias power, 41: First baffle plate, 42: Second baffle plate, 51: 1st power supply, 52: Second power supply.

Claims

Claim 1 A plasma processing apparatus comprising: a chamber; a substrate support member installed within the chamber; a plasma generating member configured to generate plasma from gas within the chamber; a bias power source configured to periodically supply electric bias energy having a waveform period to the substrate support member; a first baffle plate and a second baffle plate disposed within the chamber; a first power source electrically connected to the first baffle plate; and a second power source electrically connected to the second baffle plate, wherein the first baffle plate is disposed between the second baffle plate and a processing space within the chamber in which a substrate disposed on the substrate support member is processed therein, and the second baffle plate is disposed between the first baffle plate and an exhaust space within the chamber to which an exhaust system is connected, and wherein, for at least a portion of the waveform period, the value of the voltage applied to the second baffle plate by the second power source is higher than the value of the voltage applied to the first baffle plate by the first power source. Claim 2 A plasma processing apparatus according to claim 1, wherein, throughout the entire waveform period, the value of the voltage applied to the second baffle plate by the second power source is higher than the value of the voltage applied to the first baffle plate by the first power source. Claim 3 A plasma processing apparatus according to claim 1, wherein the waveform period includes a positive phase period in which the potential of the substrate is higher than the average potential of the substrate within the waveform period and a negative phase period in which the potential of the substrate is lower than the average potential, and during the negative phase period, the value of the voltage applied to the second baffle plate by the second power source is higher than the value of the voltage applied to the first baffle plate by the first power source. Claim 4 A plasma processing apparatus according to claim 2 or 3, wherein the value of the voltage applied to the second baffle plate by the second power source is constant. Claim 5 A plasma processing apparatus according to claim 1, wherein the waveform period includes a positive phase period in which the potential of the substrate is higher than the average potential of the substrate within the waveform period and a negative phase period in which the potential of the substrate is lower than the average potential, and during the positive phase period, the value of the voltage applied to the second baffle plate by the second power source is higher than the value of the voltage applied to the first baffle plate by the first power source. Claim 6 A plasma processing apparatus according to claim 5, wherein the value of the voltage applied to the first baffle plate by the first power source is constant. Claim 7 A plasma processing apparatus according to claim 1, wherein the chamber is grounded, and in the waveform period, the potential of the second baffle plate is higher than the potential of the chamber. Claim 8 A plasma processing apparatus according to claim 1, wherein the first baffle plate and the second baffle plate extend between the outer circumference of the substrate support and the side wall of the chamber. Claim 9 A plasma processing device according to claim 1, wherein at least one of the first baffle plate and the second baffle plate is movable. Claim 10 A plasma processing apparatus according to claim 1, wherein the electric bias energy is a bias high-frequency power having a frequency that is the inverse of the time length of the waveform period, or a pulse of voltage that is periodically applied to the substrate support at time intervals equal to the time length of the waveform period. Claim 11 A plasma processing method comprising: a process of generating plasma within a chamber of a plasma processing apparatus; a process of supplying electric bias energy having a waveform period to a substrate support disposed within the chamber; and a process of applying voltage to each of a first baffle plate and a second baffle plate disposed within the chamber, wherein the first baffle plate is disposed between the second baffle plate and a processing space within the chamber in which a substrate disposed on the substrate support is processed therein, and the second baffle plate is disposed between the first baffle plate and an exhaust space within the chamber to which an exhaust system is connected, and wherein, for at least a portion of the waveform period, the value of the voltage applied to the second baffle plate is higher than the value of the voltage applied to the first baffle plate.

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