Plasma processing apparatus and plasma processing method

Abstract

To provide a technique for suppressing the diffusion of charged particles from a processing space within a chamber to an exhaust space within the chamber.SOLUTION: A plasma processing apparatus includes a first baffle plate and a second baffle plate. The first baffle plate and the second baffle plate are disposed within a chamber between a processing space and an exhaust space. The second baffle plate is provided on the downstream side of the first baffle plate in a gas flow within the chamber. The value of voltage applied to the second baffle plate is higher than the value of voltage applied to the first baffle plate during at least a partial period of a waveform period of electrical bias energy periodically applied to a substrate support portion in the chamber.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] Exemplary embodiments of this disclosure relate to a plasma processing apparatus and a plasma processing method. [Background technology]

[0002] A plasma processing apparatus is used for plasma processing of substrates. The plasma processing apparatus comprises a chamber, a substrate support section, and a baffle plate. The substrate support section is located inside the chamber. The baffle plate is located between the substrate support section and the side wall of the chamber. The baffle plate is interposed between the processing space and the exhaust space and provides multiple through-holes. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-3958 Summary of the Invention [Problem to be solved by the invention]

[0004] This disclosure provides a technique for suppressing the diffusion of charged particles from the processing space within the chamber to the exhaust space within the chamber. [Means for 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 generation unit, a bias power supply, a first baffle plate and a second baffle plate, a first power supply, and a second power supply. The substrate support is provided within the chamber. The plasma generation unit is configured to generate plasma from a gas within the chamber. The bias power supply 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 located within the chamber. The first power supply is electrically connected to the first baffle plate. The second power supply is electrically connected to the second baffle plate. The first baffle plate is located between the processing space within the chamber, in which a substrate placed on the substrate support is processed, and the second baffle plate. The second baffle plate is located between the exhaust space within the chamber, to which an exhaust system is connected, and the first baffle plate. For at least a portion of the waveform period, the voltage applied to the second baffle plate by the second power supply is higher than the voltage applied to the first baffle plate by the first power supply. [Effects of the Invention]

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

[0007] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a plasma processing system. [Figure 2] FIG. 1 is a diagram illustrating an example of the configuration of a capacitively coupled plasma processing apparatus. [Figure 3] FIG. 2 is a diagram illustrating an example of a connection between a first power source and a second power source. [Figure 4] FIG. 10 is a diagram illustrating another example of the first power source and the second power source. [Figure 5] FIG. 10 is a diagram illustrating another example of the first power source and the second power source. [Figure 6]Each of FIGS. 6(a), 6(b), and 6(c) is a timing chart relating to a plasma processing apparatus according to one example embodiment. [Figure 7] Each of FIGS. 7(a), 7(b), 7(c), and 7(d) is a timing chart relating to a plasma processing apparatus according to one example embodiment. [Figure 8] Each of FIGS. 8(a) and 8(b) is a timing chart relating to a plasma processing apparatus according to one example embodiment. [Figure 9] 1 is a flow diagram of a plasma processing method according to an exemplary embodiment. DETAILED DESCRIPTION OF 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 generation unit, a bias power supply, a first baffle plate and a second baffle plate, a first power supply, and a second power supply. The substrate support is provided within the chamber. The plasma generation unit is configured to generate plasma from a gas within the chamber. The bias power supply 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 located within the chamber. The first power supply is electrically connected to the first baffle plate. The second power supply is electrically connected to the second baffle plate. The first baffle plate is located between the processing space within the chamber, in which a substrate placed on the substrate support is processed, and the second baffle plate. The second baffle plate is located between the exhaust space within the chamber, to which an exhaust system is connected, and the first baffle plate. For at least a portion of the waveform period, the voltage applied to the second baffle plate by the second power supply is higher than the voltage applied to the first baffle plate by the first power supply.

[0010] When the potential of the second baffle plate is higher than the potential of the first baffle plate, the flow of positive ions from the plasma in the processing space from the first baffle plate to the second baffle plate is suppressed. Therefore, 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 supply may be higher than the value of the voltage applied to the first baffle plate by the first power supply during all waveform periods.

[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 voltage applied to the second baffle plate by the second power supply may be higher than the voltage applied to the first baffle plate by the first power supply.

[0013] In one exemplary embodiment, the value of the voltage applied to the second baffle plate by the second power supply 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 voltage applied to the second baffle plate by the second power supply may be higher than the voltage applied to the first baffle plate by the first power supply.

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

[0016] In one exemplary embodiment, the chamber may be grounded. During the 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 periphery of the substrate support and the sidewall 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 electrical bias energy may be bias radio frequency power having a frequency that is the inverse of the time length of the waveform period, or may be a pulse of voltage applied to the substrate support for a time interval equal to the time length of the waveform period.

[0020] In another exemplary embodiment, a plasma processing method is provided. The plasma processing method includes generating plasma in a chamber of a plasma processing apparatus. The plasma processing method further includes supplying electrical bias energy having a waveform period to a substrate support disposed in the chamber. The plasma processing method further includes applying a voltage to each of a first baffle plate and a second baffle plate disposed in the chamber. The first baffle plate is disposed between a processing space in the chamber in which a substrate disposed on the substrate support is processed and the second baffle plate. The second baffle plate is disposed between an exhaust space in the chamber to which an exhaust system is connected and the first baffle plate. During 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 will be described in detail below with reference to the drawings, in which the same or equivalent parts are designated by the same reference numerals.

[0022] FIG. 1 is a diagram illustrating an exemplary 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 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 exhaust port for exhausting gas from the plasma processing space. The gas supply port is connected to a gas supply unit 20 (described later), and the gas exhaust port is connected to an exhaust system 40 (described later). The substrate support 11 is disposed in the plasma processing space and has a substrate support surface for supporting a substrate.

[0023] The plasma generating unit 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma generated in the plasma processing space may be capacitively coupled plasma (CCP), inductively coupled plasma (ICP), electron-cyclotron-resonance plasma (ECR plasma), helicon wave plasma (HWP), surface wave plasma (SWP), or the like.

[0024] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to perform 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, part or all of the control unit 2 may be included in the plasma processing apparatus 1. The control unit 2 may include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The control unit 2 is implemented, for example, by a computer 2a. The processing unit 2a1 may be configured to perform various control operations by reading a program from the storage unit 2a2 and executing the read program. This program may be stored in the storage unit 2a2 in advance, or it may be obtained via a medium when needed. The obtained program is stored in the storage unit 2a2 and read from the storage 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 processing unit 2a1 may be a CPU (Central Processing Unit). The storage unit 2a2 may include a random access memory (RAM), a read only memory (ROM), a hard disk drive (HDD), a solid state drive (SSD), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing apparatus 1 via a communication line such as a local area network (LAN).

[0025] The following describes a configuration example of a capacitively coupled plasma processing apparatus as an example of the plasma processing apparatus 1. Fig. 2 is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus.

[0026] The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, and an exhaust system 40. The plasma processing apparatus 1 also includes a substrate support 11 and a gas inlet. The gas inlet is configured to introduce at least one process gas into the plasma processing chamber 10. The gas inlet includes a showerhead 13. The substrate support 11 is disposed within the plasma processing chamber 10. The showerhead 13 is disposed above the substrate support 11. In one embodiment, the showerhead 13 forms at least a portion of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has an interior space 10s defined by the showerhead 13, a sidewall 10a of the plasma processing chamber 10, and the substrate support 11. The interior 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 11 includes a main body 111 and a ring assembly 112. The main body 111 has a central region 111a for supporting a substrate W and an annular region 111b for supporting the ring assembly 112. A wafer is an example of a substrate W. The annular region 111b of the main body 111 surrounds the central region 111a of the main body 111 in a plan view. The substrate W is disposed on the central region 111a of the main body 111, and the ring assembly 112 is disposed on the annular region 111b of the main body 111 so as to surround the substrate W on the central region 111a of the main body 111. Therefore, the central region 111a is also called a substrate support surface for supporting the substrate W, and the annular region 111b is also called 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. Note that the annular region 111b may also be provided by another member surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member. 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.

[0029] The ring assembly 112 includes one or more 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 rings are formed of a conductive or insulating material, and the cover rings are formed of an insulating material.

[0030] The substrate support 11 may also include a temperature adjustment module configured to adjust at least one of the electrostatic chuck 1111, the ring assembly 112, and the substrate to a target temperature. The temperature adjustment module may include a heater, a heat transfer medium, a flow passage 1110a, or a combination thereof. A heat transfer fluid such as brine or a gas flows through the flow passage 1110a. In one embodiment, the flow passage 1110a is formed in the base 1110, and one or more heaters are disposed in the ceramic member 1111a of the electrostatic chuck 1111. The substrate support 11 may also include a heat transfer gas supply configured to supply a heat transfer gas to a gap between the backside 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 through the plurality of gas inlet ports 13c. The shower head 13 also includes at least one upper electrode. In addition to the shower head 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.

[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 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.

[0033] 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 gas outlet 10e is connected to the exhaust space 10se. The exhaust system 40 is connected to the processing space 10sp via the exhaust space 10se. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure regulating valve regulates the pressure in the internal space 10s. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0034] The plasma processing apparatus 1 further includes a high frequency power supply 31 and a bias power supply 32. The high frequency power supply 31 constitutes the plasma generating unit 12 of one embodiment. The high frequency power supply 31 is configured to generate a source high frequency power RF. The source high frequency power RF has a source frequency f RF The source frequency f RF The 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 via a matching box 33 and is 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 provided in the ceramic member 1111a, or an upper electrode. When the 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 circuit 33 has a variable impedance. The variable impedance of the matching circuit 33 is set so as to reduce reflection of the source high frequency power RF from the load. The matching circuit 33 can be controlled by the control unit 2, for example.

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

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

[0038] The electrical bias energy BE may be a bias high-frequency power having a bias frequency (see Figures 6(a) and 7(a)). That is, the electrical 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 via a matching circuit 34. The variable impedance of the matching circuit 34 is set to reduce reflection of the bias high-frequency power LF from the load.

[0039] Alternatively, the electrical bias energy BE may include a voltage pulse (see Figure 8(a)). The voltage pulse is applied to the bias electrode within a waveform period CY. The voltage pulse is applied to the bias electrode periodically at time intervals equal to the length of the waveform period CY. The waveform of the voltage pulse can be a square wave, a triangular wave, or any other waveform. The polarity of the voltage pulse is set to create a potential difference between the substrate W and the plasma, thereby attracting ions from the plasma to the substrate W. In one example, the voltage pulse may be a negative voltage pulse. Note that if the electrical bias energy BE is a voltage pulse, the plasma processing apparatus 1 does not need to be equipped with a matching unit 34.

[0040] The plasma processing apparatus 1 further includes a first baffle plate 41 and a second baffle plate 42. The first baffle plate 41 and the second baffle plate 42 are provided in the chamber 10. The first baffle plate 41 is disposed between the processing space 10sp and the second baffle plate 42. The processing space 10sp is a space within the chamber 10 in which a substrate W placed on the substrate support 11 is processed. The second baffle plate 42 is disposed 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 disposed upstream of the second baffle plate 42 in the gas flow within the chamber 10. The second baffle plate 42 is disposed downstream of the first baffle plate 41.

[0041] 2 , the first baffle plate 41 and the second baffle plate 42 extend between the outer periphery of the substrate support 11 and the sidewall of the chamber 10, and extend circumferentially around the substrate support 11. The outer edges of the first baffle plate 41 and the second baffle plate 42 are supported by an insulating member 43. The inner edges of the first baffle plate 41 and the second baffle plate 42 are supported by the 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 apparatus 1 further includes 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 positions of the first baffle plate 41 and the second baffle plate 42. The driving unit 44 may 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 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 apparatus 1 further includes a first power supply 51 and a second power supply 52. ​​The first power supply 51 and the second power supply 52 are, for example, variable DC power supplies. The first power supply 51 is electrically connected to the first baffle plate 41. The second power supply 52 is electrically connected to the second baffle plate 42. Specifically, one pole (e.g., negative pole) of the first power supply 51 is electrically connected to the first baffle plate 41 via a filter 51f. One pole (e.g., negative pole) of the second power supply 52 is electrically connected to the second baffle plate 42 via a filter 52f. Each of the filters 51f and 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 supply 51 and the second power supply 52 is connected to ground.

[0044] Here, reference is made to Fig. 3. Fig. 3 is a diagram showing an example of the connection of the first power supply and the second power supply. As shown in Fig. 3, the other pole (e.g., positive pole) of the second power supply 52 may be connected to one pole (e.g., negative pole) of the first power supply 51.

[0045] Reference will now be made to FIGS. 4 and 5. Each of FIGS. 4 and 5 illustrates another example of a first power supply and a second power supply. In the example illustrated in FIGS. 4 and 5, the first power supply 51 includes a power supply 511 and a power supply 512. The second power supply 52 includes a power supply 521 and a power supply 522. The power supplies 511, 512, 521, and 522 are, for example, variable DC power supplies. The negative terminal of the power supply 511 is connected to the output 51o of the first power supply 51 via a switch. The positive terminal of the power supply 511 is connected to ground. The positive terminal of the power supply 512 is connected to the output 51o of the first power supply 51 via a switch. The negative terminal of the power supply 512 is connected to ground. The output 51o of the first power supply 51 is connected to the first baffle plate 41 via a filter 51f. The negative terminal of the power supply 521 is connected to the output 52o of the second power supply 52 via a switch. The positive terminal of the power supply 522 is connected to the output 52o of the second power supply 52 via a switch. An output 52o of the second power supply 52 is connected to the second baffle plate 42 via a filter 52f. In the example shown in FIG. 4, the positive electrode of the power supply 521 and the negative electrode of the power supply 512 are connected to ground. In the example shown in FIG. 5, the positive electrode of the power supply 521 and the negative electrode of the power supply 512 are connected to the output 51o of the first power supply 51. In the examples shown in FIGS. 4 and 5, the first power supply 51 and the second power supply 52 are configured as power supplies that can switch the polarity of the voltage they output. Note that each of the first power supply 51 and the second power supply 52 may be a bipolar power supply that can continuously output both a positive voltage and a negative voltage.

[0046] Hereafter, we will refer to Figure 6(a), Figure 6(b), Figure 6(c), Figure 7(a), Figure 7(b), Figure 7(c), Figure 7(d), Figure 8(a), and Figure 8(b) together with Figure 1. These figures are timing charts related to a plasma processing apparatus according to one exemplary embodiment. Specifically, Figures 6(a), 7(a), and 8(a) each show an exemplary timing chart for the electrical bias energy. Figures 6(b), 6(c), 7(b), 7(c), and 7(d) each show exemplary timing charts for the potential of the first electrode P41, the potential of the second electrode P42, and the plasma potential PP. Figure 8(b) shows an exemplary timing chart for the potential of the first electrode P41 and the potential of the second electrode P42.

[0047] As shown in Figures 6(a), 7(a), and 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 in response to the electrical bias energy BE.

[0048] The plasma potential PP changes depending on the electrical 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 voltage applied to the second baffle plate 42 by the second power supply 52 is higher than the voltage applied to the first baffle plate 41 by the first power supply 51. Therefore, as shown in the figure, 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, positive ions from the plasma in the processing space 10sp are prevented from flowing from the first baffle plate 41 toward the second baffle plate 42. Therefore, it is possible to prevent the diffusion of charged particles from the processing space 10sp to the exhaust space 10se.

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

[0052] In one embodiment, as shown in (b) of FIG. 6 and (b) of FIG. 8, during the negative phase period N1, the value of the voltage applied to the second baffle plate 42 by the second power supply 52 is higher than the value of the voltage applied to the first baffle plate 41 by the first power supply 51. Therefore, during the negative phase period N1, 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 P1, the value of the voltage applied to the second baffle plate 42 by the second power supply 52 is lower than the value of the voltage applied to the first baffle plate 41 by the first power supply 51. Therefore, during the positive phase period P1, the potential P42 of the second baffle plate 42 is lower than the potential P41 of the first baffle plate 41. During the entire waveform period CY, the voltage applied to the first baffle plate 41 by the first power supply 51 and the voltage applied to the second baffle plate 42 by the second power supply 52 are positive. Therefore, during the entire 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 supply 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 supply 52 is constant.

[0053] 6(b) and 8(b), 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. Furthermore, during the negative phase period NI, secondary electrons that may be emitted from the first baffle plate 41 are captured by the second baffle plate 42, and therefore, the secondary electrons are suppressed from flowing into the exhaust space 10se.

[0054] In another embodiment, as shown in Figure 6(c), throughout the entire waveform period CY, the voltage applied to the second baffle plate 42 by the second power supply 52 is higher than the voltage applied to the first baffle plate 41 by the first power supply 51. Therefore, throughout the entire waveform period CY, the potential P42 of the second baffle plate 42 is higher than the potential P41 of the first baffle plate 41. Throughout the entire waveform period CY, the voltage applied to the first baffle plate 41 by the first power supply 51 and the voltage applied to the second baffle plate 42 by the second power supply 52 are positive values. Therefore, throughout the entire 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 supply 51 has a waveform that follows the waveform of the plasma potential PP. The voltage applied to the second baffle plate 42 by the second power supply 52 is constant.

[0055] In the embodiment shown in Figure 6(c), the flow of positive ions from the plasma in the processing space 10sp from the first baffle plate 41 to the second baffle plate 42 is suppressed throughout the entire waveform period CY. Furthermore, throughout the entire waveform period CY, secondary electrons that could be emitted from the first baffle plate 41 are captured by the second baffle plate 42, thus suppressing the flow of secondary electrons into the exhaust space 10se.

[0056] In yet another embodiment, as shown in Figure 7(b), throughout the entire waveform period CY, the voltage applied to the second baffle plate 42 by the second power supply 52 is higher than the voltage applied to the first baffle plate 41 by the first power supply 51. Therefore, throughout the entire waveform period CY, the potential P42 of the second baffle plate 42 is higher than the potential P41 of the first baffle plate 41. Throughout the entire waveform period CY, the voltage applied to the second baffle plate 42 by the second power supply 52 is a positive value. Therefore, throughout the entire 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 supply 51 is a negative value during the negative phase period NI and a positive value during the positive phase period PI. The voltage applied to the first baffle plate 41 by the first power supply 51 and the voltage applied to the second baffle plate 42 by the second power supply 52 have waveforms that follow the waveform of the plasma potential PP.

[0057] In the embodiment shown in Figure 7(b), the flow of positive ions from the plasma in the processing space 10sp from the first baffle plate 41 to the second baffle plate 42 is suppressed throughout the entire waveform period CY. Furthermore, throughout the entire waveform period CY, secondary electrons that could be emitted from the first baffle plate 41 are captured by the second baffle plate 42, thus suppressing the flow of secondary electrons into the exhaust space 10se.

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

[0059] 7(c), in the entire waveform period CY, 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 addition, in the entire waveform period CY, secondary electrons that may be emitted from the first baffle plate 41 are captured by the second baffle plate 42, and therefore, the secondary electrons are suppressed from flowing into the exhaust space 10se.

[0060] In yet another embodiment, as shown in FIG. 7(d), during the positive phase period PI, the voltage applied to the second baffle plate 42 by the second power supply 52 is higher than the voltage applied to the first baffle plate 41 by the first power supply 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 voltage applied to the second baffle plate 42 by the second power supply 52 is lower than the voltage applied to the first baffle plate 41 by the first power supply 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. Throughout the waveform period CY, the voltage applied to the first baffle plate 41 by the first power supply 51 and the voltage applied to the second baffle plate 42 by the second power supply 52 are both positive values. Therefore, throughout the entire 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 second baffle plate 42 by the second power supply 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 supply 51 is constant.

[0061] 7(d), during the positive phase period PI, 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. Furthermore, during the positive phase period PI, secondary electrons that may be emitted from the first baffle plate 41 are captured by the second baffle plate 42, and therefore, the secondary electrons are suppressed from flowing into the exhaust space 10se.

[0062] Reference will now be made to Fig. 9, which is a flow chart of a plasma processing method according to one example embodiment. The plasma processing method shown in Fig. 9 (hereinafter referred to as "method MT") can be applied to a plasma processing apparatus 1. The method MT includes steps STa to STc.

[0063] In step STa, plasma is generated in the chamber 10. In step STa, gas is supplied from the gas supply unit 20 to the processing space 10sp. In step STa, the exhaust system 40 reduces the pressure in the chamber 10 to a specified pressure. In step STa, plasma is generated from the gas in the processing space 10sp by the plasma generation unit 12. In one embodiment, source radio frequency power RF from the radio frequency power supply 31 is supplied to the radio frequency electrode.

[0064] Step STb is performed while the plasma is being generated in step STa. In step STb, electrical bias energy BE is supplied to the substrate support 11.

[0065] Step STc is performed while electrical bias energy BE is being supplied to the substrate support 11 in step STb. In step STc, a voltage is applied to each of the first baffle plate 41 and the second baffle plate 42, as described above. As described above, 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 during at least a portion of the waveform period CY.

[0066] Although various exemplary embodiments have been described above, the present invention is not limited to the above-described exemplary embodiments, and various additions, omissions, substitutions, and modifications may be made. Furthermore, elements in different embodiments may be combined to form other embodiments.

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

[0068] From the foregoing, it will be understood that various embodiments of the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope and spirit of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, with the true scope and spirit being indicated by the appended claims. [Explanation of symbols]

[0069] 1...plasma processing apparatus, 10...chamber, 11...substrate support part, 12...plasma generation part, 32...bias power supply, 41...first baffle plate, 42...second baffle plate, 51...first power supply, 52...second power supply.

Claims

1. a chamber; a substrate support disposed within the chamber; a plasma generating unit configured to generate plasma from the gas within the chamber; a bias power supply configured to periodically supply electrical bias energy having a waveform period to the substrate support; a first baffle plate and a second baffle plate disposed within the chamber; a first power supply electrically connected to the first baffle plate; a second power supply electrically connected to the second baffle plate; Equipped with the first baffle plate is disposed between a processing space in the chamber in which a substrate disposed on the substrate support is processed and the second baffle plate; the second baffle plate is disposed between an exhaust space in the chamber to which an exhaust system is connected and the first baffle plate; During at least a portion of the waveform period, the value of the voltage applied to the second baffle plate by the second power supply is higher than the value of the voltage applied to the first baffle plate by the first power supply. Plasma processing equipment.

2. 2. The plasma processing apparatus of claim 1, wherein the value of the voltage applied to the second baffle plate by the second power supply is higher than the value of the voltage applied to the first baffle plate by the first power supply during all of the waveform periods.

3. the waveform period includes a positive phase period in which the potential of the substrate is higher than an 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 supply is higher than the value of the voltage applied to the first baffle plate by the first power supply. The plasma processing apparatus according to claim 1 .

4. 4. The plasma processing apparatus according to claim 2, wherein the value of the voltage applied to the second baffle plate by the second power supply is constant.

5. the waveform period includes a positive phase period in which the potential of the substrate is higher than an 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 supply is higher than the value of the voltage applied to the first baffle plate by the first power supply. The plasma processing apparatus according to claim 1 .

6. The plasma processing apparatus of claim 5 , wherein the value of the voltage applied to the first baffle plate by the first power supply is constant.

7. the chamber is grounded; During the waveform period, the potential of the second baffle plate is higher than the potential of the chamber. The plasma processing apparatus according to any one of claims 1 to 6.

8. 8. The plasma processing apparatus according to claim 1, wherein the first baffle plate and the second baffle plate extend between an outer periphery of the substrate support and a sidewall of the chamber.

9. 9. The plasma processing apparatus according to claim 1, wherein at least one of the first baffle plate and the second baffle plate is movable.

10. 10. The plasma processing apparatus according to claim 1, wherein the electrical 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 voltage pulse that is applied to the substrate support periodically at a time interval equal to the time length of the waveform period.

11. generating a plasma in a chamber of a plasma processing device; applying electrical bias energy having a waveform period to a substrate support disposed within the chamber; applying a voltage to each of a first baffle plate and a second baffle plate disposed within the chamber; Including, the first baffle plate is disposed between a processing space in the chamber in which a substrate disposed on the substrate support is processed and the second baffle plate; the second baffle plate is disposed between an exhaust space in the chamber to which an exhaust system is connected and the first baffle plate; During 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. Plasma treatment method.

Images