Plasma Processing Apparatus and Plasma Processing Method

Abstract

To provide a technique for selectively using ions or radicals of remote plasma.SOLUTION: In a plasma processor, the inner space of a chamber is divided into a first space between an upper electrode and a shower head and a second space below the shower head, and a plurality of openings are provided to penetrate the shower head so that the first space and the second space connect to each other. A shielding part is provided between the upper electrode and the shower head and has a first shielding plate and a second shielding plate arranged in parallel to each other along the shower head, and a plurality of through-holes are arranged so that the first shielding plate and the second shielding plate are aligned with the openings of the shower head. A voltage application unit is formed to select ions or radicals of the plasma which are to pass through the plurality of through-holes by applying a control voltage on the shielding part. A control unit is formed to control the voltage application unit.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Exemplary embodiments of the present disclosure relate to a plasma processing apparatus and a plasma processing method.

Background Art

[0002] Plasma processing is performed as a type of substrate processing. In plasma processing, a substrate is processed by chemical species from plasma generated in a chamber. Chemical species in the plasma include ions and radicals. Since ions can damage the substrate, substrate processing using radicals may be performed. Patent Document 1 below discloses a technique for removing ions in remote plasma by an ion trap provided directly below a shower plate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a technique for selectively using ions and radicals of remote plasma.

Means for Solving the Problems

[0005] In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus may include a chamber, an upper electrode, a shower head, a substrate support, a shielding portion, a gas supply portion, a high-frequency power source, a voltage application portion, and a control portion. The shower head may be provided below the upper electrode. The internal space of the chamber may be divided into a first space between the upper electrode and the shower head and a second space below the shower head. A plurality of openings may be provided that penetrate the shower head to communicate the first space and the second space with each other. The substrate support may be configured to support a substrate within the second space. The shielding portion may be provided between the upper electrode and the shower head. It may have a first shielding plate and a second shielding plate arranged in parallel with each other along the shower head. The second shielding plate may be provided on the shower head. The first shielding plate may be provided on the second shielding plate. The first shielding plate and the second shielding plate may provide a plurality of through holes arranged to align with the plurality of openings of the shower head. The gas supply portion may be configured to supply gas to a region within the first space between the upper electrode and the shielding portion. The high-frequency power source may be configured to output a high-frequency voltage to generate plasma of the gas. The voltage application portion may be configured to select ions or radicals that pass through the plurality of through holes among the plasma by applying a control voltage to the shielding portion. The control portion may be configured to control the voltage application portion. The voltage application portion may be configured to apply a control voltage independently to each of the first shielding plate and the second shielding plate in response to control received from the control portion.

Effect of the Invention

[0006] According to one exemplary embodiment, ions and radicals of remote plasma can be selectively used.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

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Figure 8

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Figure 11

Figure 12

Mode for Carrying Out the Invention

[0008] Hereinafter, various exemplary embodiments will be described.

[0009] In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus may include a chamber, an upper electrode, a shower head, a substrate support, a shielding portion, a gas supply unit, a high-frequency power source, a voltage application unit, and a control unit. The shower head may be provided below the upper electrode. The internal space of the chamber may be divided into a first space between the upper electrode and the shower head and a second space below the shower head. A plurality of openings may be provided that penetrate the shower head to communicate the first space and the second space with each other. The substrate support may be configured to support a substrate within the second space. The shielding portion may be provided between the upper electrode and the shower head. It may have a first shielding plate and a second shielding plate arranged in parallel with each other along the shower head. The second shielding plate may be provided on the shower head. The first shielding plate may be provided on the second shielding plate. The first shielding plate and the second shielding plate may provide a plurality of through holes arranged to align with the plurality of openings of the shower head. The gas supply unit may be configured to supply gas to a region within the first space between the upper electrode and the shielding portion. The high-frequency power source may be configured to output a high-frequency voltage to generate plasma of the gas. The voltage application unit may be configured to select ions or radicals that pass through the plurality of through holes among the plasma by applying a control voltage to the shielding portion. The control unit may be configured to control the voltage application unit. The voltage application unit may be configured to apply a control voltage independently to each of the first shielding plate and the second shielding plate in response to control received from the control unit.

[0010] Thus, a control voltage can be independently applied to each of the first shielding plate and the second shielding plate. Therefore, among the plasma in the space between the upper electrode and the shielding portion in the first region, the type of particles (any one of positive ions, negative ions and electrons, and radicals) that pass through the shielding portion and the shower head can be selected.

[0011] In one exemplary embodiment, each of the first shielding plate and the second shielding plate may include a metal plate coated with an insulating coating. The voltage application unit may include a first pulse generator, a second pulse generator, a first variable DC power supply, and a second variable DC power supply. The first pulse generator and the second pulse generator may be configured to output a rectangular-wave control voltage. The first shielding plate, the first pulse generator, and the first variable DC power supply may be electrically connected in series in this order. The second shielding plate, the second pulse generator, and the second variable DC power supply may be electrically connected in series in this order. The control unit may control the voltage application unit so as to apply rectangular-wave control voltages having opposite phases to each of the first shielding plate and the second shielding plate.

[0012] In one exemplary embodiment, each of the first shielding plate and the second shielding plate may include an uncoated metal plate. The voltage application unit may include a first variable DC power supply and a second variable DC power supply. The first shielding plate and the first variable DC power supply may be electrically connected in series in this order. The second shielding plate and the second variable DC power supply may be electrically connected in series in this order. The control unit may control the voltage application unit so as to apply a DC control voltage to each of the first shielding plate and the second shielding plate.

[0013] In one exemplary embodiment, the control unit may control the voltage application unit so that the absolute value of the control voltage applied to the second shielding plate is greater than or equal to the absolute value of the control voltage applied to the first shielding plate.

[0014] In one exemplary embodiment, it may further include an electric circuit electrically connected to a high-frequency power supply. The high-frequency power supply may be electrically connected to an upper electrode and generate a plasma of a gas by applying a high-frequency voltage to the upper electrode. The electric circuit may include a diode electrically connected between the high-frequency power supply and the ground. The anode of the diode may be electrically connected to the high-frequency power supply, and the cathode of the diode may be electrically connected to the ground.

[0015] In one exemplary embodiment, the plasma processing apparatus may further include a coil and an electrical circuit. The coil is electrically connected to a high-frequency power source and may extend along the upper electrode on the upper electrode. The electrical circuit may be electrically connected to the high-frequency power source via the coil. The high-frequency power source may generate plasma of a gas by applying a high-frequency voltage to the coil. The electrical circuit may have a capacitor electrically connected between the high-frequency power source and the ground.

[0016] In one exemplary embodiment, a plasma processing method is provided. The plasma processing method is a method of processing a substrate using a plasma processing apparatus. The plasma processing apparatus includes a shower head, a shielding portion, and a high-frequency power source. The shower head may be provided below the upper electrode. The internal space of the chamber may be divided into a first space between the upper electrode and the shower head and a second space below the shower head. A plurality of openings may be provided through the shower head to communicate the first space and the second space with each other. The shielding portion may be provided between the upper electrode and the shower head. The shielding portion may have a first shielding plate and a second shielding plate arranged in parallel with each other along the shower head. The second shielding plate may be provided on the shower head. The first shielding plate may be provided on the second shielding plate. The first shielding plate and the second shielding plate may provide a plurality of through holes arranged to align with the plurality of openings of the shower head. The high-frequency power source may be configured to output a high-frequency voltage to generate plasma of a gas supplied from the gas supply portion to a region within the first space. This plasma processing method includes steps a, b, c, and d. Step a may prepare a substrate on a substrate support portion configured to support the substrate within the second space. Step b may apply a high-frequency voltage to the upper electrode. Step c may generate plasma in the space between the upper electrode and the shielding portion by the high-frequency voltage. Step d may apply a control voltage to the shielding portion to select ions or radicals passing through the plurality of through holes among the plasma. Step d may apply a control voltage to each of the first shielding plate and the second shielding plate independently of each other.

[0017] In this way, a control voltage can be independently applied to each of the first shielding plate and the second shielding plate. Therefore, among the plasmas in the space between the upper electrode and the shielding portion in the first region, the type of particles (any one of positive ions, negative ions and electrons, and radicals) passing through the shielding portion and the shower head can be selected.

[0018] Hereinafter, various exemplary embodiments will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts will be denoted by the same reference numerals.

[0019] FIG. 1 is a diagram schematically showing a plasma processing apparatus according to one exemplary embodiment. The plasma processing apparatus 1 shown in FIG. 1 is a capacitively coupled plasma (CCP) type plasma processing apparatus and includes a chamber 10. The chamber 10 has a substantially cylindrical shape. The chamber 10 is formed of a conductive material such as aluminum. The chamber 10 is grounded. The chamber 10 provides an internal space 10s therein.

[0020] The plasma processing apparatus 1 further includes an upper electrode 12. The upper electrode 12 extends above a substrate support portion 16 described later. In one embodiment, the upper electrode 12 closes the upper end opening of the chamber 10 together with a member 13. The upper electrode 12 has a substantially disk shape and is formed of a conductive material such as aluminum. The member 13 is formed of an insulating material. The member 13 is interposed between the upper end of the chamber 10 and the upper electrode 12.

[0021] The plasma processing apparatus 1 further includes a shower head 14. The shower head 14 is provided below the upper electrode 12. The shower head 14 has a substantially disk shape. The shower head 14 is formed of a conductive material such as aluminum. The shower head 14 divides the internal space 10s into a space S1 and a space S2. The space S1 is the space between the upper electrode 12 and the shower head 14. The space S2 is the space below the shower head 14.

[0022] In one embodiment, the member 15 may be provided between the upper electrode 12 and the shower head 14. The member 15 has a cylindrical shape and is formed of an insulating material such as aluminum oxide. The space S1 is provided between the upper electrode 12 and the shower head 14 and inside the member 15.

[0023] The shower head 14 provides a plurality of inlets 14i and a plurality of openings 14h. The plurality of inlets 14i are formed in the shower head 14 to introduce gas into the space S2. The plurality of openings 14h are formed in the shower head 14 to communicate the space S1 and the space S2 with each other.

[0024] The chamber 10 has side walls. The side walls of the chamber 10 provide a passage 10p. The substrate W passes through the passage 10p when being transported between the space S2 and the outside of the chamber 10. The plasma processing apparatus 1 may further include a gate valve 10g. The gate valve 10g is provided along the side wall of the chamber 10 to open and close the passage 10p.

[0025] The plasma processing apparatus 1 further includes a substrate support 16. The substrate support 16 is configured to support the substrate W in the space S2. The substrate W may have a substantially disk shape. The substrate W is processed in a state of being placed on the substrate support 16 in the space S2. The substrate support 16 may be formed of an insulating ceramic such as aluminum nitride. Alternatively, the substrate support 16 may be formed of a conductive material.

[0026] In one embodiment, the substrate support 16 may be supported by a support member 17. The support member 17 may extend upward from the bottom of the chamber 10. The substrate support 16 may have a heater 16h. The heater 16h is provided in the substrate support 16. The heater 16h is configured to receive electric power supplied from a heater power source. The heater 16h is configured to heat the substrate W on the substrate support 16 to a specified temperature.

[0027] In one embodiment, the substrate support portion 16 may further include a lower electrode 16e. The lower electrode 16e is provided inside the substrate support portion 16. When the substrate support portion 16 is formed of a conductive material, the substrate support portion 16 functions as the lower electrode 16e.

[0028] The plasma processing apparatus 1 further includes a gas supply unit 20. The gas supply unit 20 is configured to supply gas to a region within the space S1 between the upper electrode 12 and the shielding portion 18, particularly to the region R1. In one embodiment, the gas supply unit 20 is connected to the gas introduction port of the upper electrode 12, and supplies gas to the region R1 through this gas introduction port.

[0029] The plasma processing apparatus 1 further includes a gas supply unit 22. The gas supply unit 22 is configured to supply gas to the shower head 14. In one embodiment, the gas supply unit 22 is connected to the shower head 14 through a pipe 23, and supplies gas to the shower head 14 through the pipe 23. The gas supplied from the gas supply unit 22 to the shower head 14 is introduced into the space S2 from a plurality of inlet ports 14i that communicate with each other within the shower head 14.

[0030] The plasma processing apparatus 1 includes one or more power supplies for generating plasma from gas within the chamber 10. The one or more power supplies are connected to the upper electrode 12. In one embodiment, the plasma processing apparatus 1 may include a high-frequency power supply 24 and a DC pulse power supply 26 as the one or more power supplies.

[0031] The high-frequency power supply 24 is configured to output a high-frequency voltage (hereinafter sometimes referred to as "the first high-frequency voltage") to generate plasma of the gas supplied from the gas supply unit 20 to the region R1. The high-frequency power supply 24 is connected to the upper electrode 12. The first high-frequency voltage is supplied to the upper electrode 12. The frequency of the first high-frequency voltage can be 300 kHz or more and 100 MHz or less. In one example, the frequency of the first high-frequency voltage may be 40 MHz.

[0032] The high-frequency power supply 24 may be connected to the upper electrode 12 via a matching unit 24m. The matching unit 24m includes a matching circuit for matching the impedance on the load side of the high-frequency power supply 24 with the output impedance of the high-frequency power supply 24. Hereinafter, "the high-frequency power supply" may be a general term for those having not only the high-frequency power supply 24 but also the matching unit 24m.

[0033] The DC pulse power supply 26 intermittently or periodically generates a pulsed DC voltage. The DC pulse power supply 26 is connected to the upper electrode 12. The pulsed DC voltage generated by the DC pulse power supply 26 is applied to the upper electrode 12. The pulsed DC voltage may have a positive polarity or a negative polarity. The frequency that determines the period of the pulsed DC voltage applied to the upper electrode 12 is 10 Hz or more and 1 MHz or less. This frequency is the reciprocal of the period of the pulsed DC voltage applied to the upper electrode 12. In one example, this frequency may be 500 kHz.

[0034] In one embodiment, the DC pulse power supply 26 may include a DC power supply 26a and a pulse unit 26b. The DC power supply 26a is a power supply that generates a DC voltage. The DC power supply 26a may be a variable DC power supply. The pulse unit 26b is connected between the DC power supply 26a and the upper electrode 12. The pulse unit 26b is configured to modulate the DC voltage from the DC power supply 26a into a pulsed DC voltage. The pulse unit 26b may be composed of one or more switching transistors.

[0035] In one embodiment, the DC pulse power supply 26 may be connected to the upper electrode 12 via the filter 26f. The filter 26f is an electrical filter that blocks or attenuates high-frequency voltage.

[0036] In one embodiment, the plasma processing apparatus 1 may further include a high-frequency power supply 30. The high-frequency power supply 30 is a power supply that generates a high-frequency voltage (hereinafter sometimes referred to as "second high-frequency voltage"). The high-frequency power supply 30 is connected to the lower electrode 16e. The second high-frequency voltage is supplied to the lower electrode 16e. The frequency of the second high-frequency voltage is 300 kHz or more and 100 MHz or less. In one example, the frequency of the second high-frequency voltage may be 400 kHz.

[0037] The high-frequency power supply 30 may be connected to the lower electrode 16e via a matching unit 30m. The matching unit 30m includes a matching circuit for matching the impedance on the load side of the high-frequency power supply 30 to the output impedance of the high-frequency power supply 30.

[0038] In one embodiment, the plasma processing apparatus 1 may further include an exhaust device 32. The exhaust device 32 is connected to the internal space 10s of the chamber 10 via an exhaust pipe 33. The exhaust device 32 may include one or more pumps such as a dry pump and a turbo molecular pump, and a pressure controller such as an automatic pressure control valve. In one embodiment, the exhaust device 32 may be connected to the space S2 via the exhaust pipe 33 and an exhaust port 10e. The exhaust port 10e may be provided at the bottom of the chamber 10.

[0039] In one embodiment, the plasma processing apparatus 1 may further include a control unit 40. The control unit 40 is configured to control each part of the plasma processing apparatus 1 such as the voltage application unit 4. The control unit 40 may be a computer having a processor, an input device, an output device, a display device, a storage device, and the like. A control program and recipe data are stored in the storage device. The processor executes the control program and controls each part of the plasma processing apparatus 1 according to the recipe data. As a result, in the plasma processing apparatus 1, plasma processing according to the recipe data is executed. The plasma processing methods according to various exemplary embodiments described below can be executed in the plasma processing apparatus 1 by controlling each part of the plasma processing apparatus 1 by the control unit 40.

[0040] The plasma processing apparatus 1 further includes a shielding portion 18. The shielding portion 18 is provided between the upper electrode 12 and the shower head 14. The shielding portion 18 divides the space S1 into a region R1 and a region R2. The region R1 is the region between the upper electrode 12 and the shielding portion 18. The region R2 is the region between the shielding portion 18 and the shower head 14.

[0041] The shielding portion 18 provides a plurality of through holes 18h. Each of the plurality of through holes 18h is arranged so as to be aligned with the plurality of openings 14h. That is, each of the plurality of through holes 18h is arranged such that the lower end thereof faces the upper end of the plurality of openings 14h. In other words, the plurality of through holes 18h and the plurality of openings 14h are arranged such that the figures projected onto a plane parallel to the substrate W overlap each other.

[0042] The shielding portion 18 has shielding plates 18a and 18b arranged parallel to each other along the shower head 14. The shielding plate 18b is provided above the shower head 14, and the shielding plate 18a is provided above the shielding plate 18b. The shielding plates 18a and 18b provide a plurality of through holes 18h arranged so as to be aligned with the plurality of openings 14h of the shower head 14.

[0043] Either the shielding plate 18a or the shielding plate 18b may include a metal plate that is not insulated (for example, a solid aluminum or nickel metal plate). Each of the shielding plate 18a and the shielding plate 18b may include a metal plate that is insulated (for example, their surfaces are made non-conductive by anodizing or spraying, such as a solid aluminum or nickel metal plate). The shielding portion 18 has a substantially disk shape. In one embodiment, the inner wall surface of the chamber 10, the surface of the upper electrode 12, the surface of the shower head 14, and the surface of the shielding portion 18 may be covered with a corrosion-resistant film. This film may be an anodized film or a yttrium oxide film.

[0044] The plasma processing apparatus 1 may further include a voltage application unit 4. The voltage application unit 4 is configured to select ions or radicals that pass through a plurality of through holes 18h among the plasma generated in the region R1 of the space S1 by applying a control voltage to the shielding portion 18. The voltage application unit 4 is configured to apply control voltages to the shielding plate 18a and the shielding plate 18b independently of each other according to the control received from the control unit 40.

[0045] FIG. 2 shows an example of a partial configuration of the plasma processing apparatus 1 when both the shielding plate 18a and the shielding plate 18b include an insulated metal plate. FIG. 2 is described briefly for the purpose of explanation. In one embodiment, the voltage application unit 4 includes a pulse generator Pa, a pulse generator Pb, a variable DC power supply Da, and a variable DC power supply Db. The shielding plate 18a, the pulse generator Pa, and the variable DC power supply Da are electrically connected in series in this order. The shielding plate 18b, the pulse generator Pb, and the variable DC power supply Db are electrically connected in series in this order. The control unit 40 controls the voltage application unit 4 so as to apply rectangular wave-shaped control voltages with opposite phases to the shielding plate 18a and the shielding plate 18b, respectively.

[0046] In one embodiment, both the pulse generator Pa and the pulse generator Pb of the voltage application unit 4 shown in FIG. 2 are configured to output a rectangular-wave control voltage. The control unit 40 controls the voltage application unit 4 so as to apply rectangular-wave (pulse-shaped) control voltages having the same frequency and opposite phases to each of the shielding plates 18a and 18b. Both the pulse generator Pa and the pulse generator Pb can output rectangular-wave (pulse-shaped) control voltages having the same frequency within the range of 0 to 1 MHz and opposite phases to each other.

[0047] Rectangular-wave control voltages having opposite phases to each other are applied to each of the shielding plates 18a and 18b. As a result, as shown in FIG. 7, the potential V1 of the shielding plate 18a and the potential V2 of the shielding plate 18b become rectangular-wave potentials having the same frequency and opposite phases to each other, similar to the control voltage.

[0048] As shown in FIG. 7, when the potential V1 of the shielding plate 18a is positive and the potential V2 of the shielding plate 18b is negative, positive ions do not pass through the through-hole 18h in the shielding plate 18a and remain in the region R1 along the direction K1 in FIG. 3. In this case, negative ions and electrons pass through the through-hole 18h in the shielding plate 18a along the direction K2 in FIG. 3 but do not pass through the through-hole 18h in the shielding plate 18b and remain in the region R1 along the direction K1 in FIG. 3. When the potential V1 of the shielding plate 18a is negative and the potential V2 of the shielding plate 18b is positive, negative ions and electrons do not pass through the through-hole 18h in the shielding plate 18a and remain in the region R1 along the direction K1 in FIG. 3. In this case, positive ions pass through the through-hole 18h in the shielding plate 18a along the direction K2 in FIG. 3 but do not pass through the through-hole 18h in the shielding plate 18b and remain in the region R1 along the direction K1 in FIG. 3. Therefore, as shown in FIG. 7, when the potential V1 of the shielding plate 18a and the potential V2 of the shielding plate 18b are rectangular-wave potentials having opposite phases to each other, radicals among the plasma generated in the region R1 can selectively pass through the through-hole 18h.

[0049] In one embodiment, both the pulse generator Pa and the pulse generator Pb may have the circuit configuration shown in FIG. 4. The pulse generator Pa and the pulse generator Pb have an input terminal Vin, a resistor RS1, a resistor RS2, an amplifier OP, a resistor RS3, a resistor RS4, a capacitor C1, a DC power supply DV, and an output terminal Vout. The input terminal Vin, the resistor RS1, and the resistor RS2 are electrically connected in series in this order, and the resistor RS2 is electrically connected to the ground. The connection point of the resistor RS1 and the resistor RS2 is electrically connected to the positive input terminal of the amplifier OP and is also electrically connected to the output terminal of the amplifier OP via the resistor RS4. The negative input terminal of the amplifier OP is electrically connected to the input terminal of the amplifier OP via the resistor RS3 and is also electrically connected to the ground via the capacitor C1.

[0050] The control unit 40 controls the voltage application unit 4 so that the absolute value of the control voltage applied to the shielding plate 18b is equal to or greater than the absolute value of the control voltage applied to the shielding plate 18a. As a result, it is possible to suppress charged particles that have unintentionally passed through the through hole 18h in the shielding plate 18a from further passing through the through hole 18h in the shielding plate 18b. Also, at the potentials V1 and V2 shown in each of FIGS. 8, 9, 10, and 11, the absolute value of the potential V2 is equal to or greater than the absolute value of the potential V1.

[0051] FIG. 3 shows an example of a partial configuration of the plasma processing apparatus 1 when both the shielding plate 18a and the shielding plate 18b include a metal plate without an insulating coating (a solid metal plate). FIG. 3 is described briefly for the sake of explanation. In one embodiment, the voltage application unit 4 has a variable DC power supply Da and a variable DC power supply Db. The shielding plate 18a and the variable DC power supply Da are electrically connected in series in this order. The shielding plate 18b and the variable DC power supply Db are electrically connected in series in this order. The control unit 40 controls the voltage application unit 4 so as to apply a DC control voltage to each of the shielding plate 18a and the shielding plate 18b.

[0052] In one embodiment, the variable DC power supplies Da and Db of the voltage application unit 4 shown in FIG. 3 are both configured to apply a DC control voltage. The control unit 40 controls the voltage application unit 4 so as to apply a DC control voltage to each of the shielding plates 18a and 18b.

[0053] When a DC control voltage is applied to each of the shielding plates 18a and 18b, as shown in FIGS. 8, 9, 10, and 11, the potential V1 of the shielding plate 18a and the potential V2 of the shielding plate 18b each become a constant potential similar to the control voltage.

[0054] As shown in FIG. 8, when the potential V1 of the shielding plate 18a is positive and the potential V2 of the shielding plate 18b is negative, positive ions do not pass through the through hole 18h of the shielding plate 18a and remain in the region R1 along the direction K1 in FIG. 3. In this case, negative ions and electrons pass through the through hole 18h in the shielding plate 18a along the direction K2 in FIG. 3 but do not pass through the through hole 18h in the shielding plate 18b and remain in the region R1 along the direction K1 in FIG. 3. Therefore, as shown in FIG. 8, when the potential V1 of the shielding plate 18a is positive and the potential V2 of the shielding plate 18b is negative, radicals among the plasma generated in the region R1 can selectively pass through the through hole 18h.

[0055] As shown in FIG. 9, when the potential V1 of the shielding plate 18a is negative and the potential V2 of the shielding plate 18b is positive, negative ions and electrons do not pass through the through hole 18h of the shielding plate 18a and remain in the region R1 along the direction K1 in FIG. 3. In this case, positive ions pass through the through hole 18h in the shielding plate 18a along the direction K2 in FIG. 3 but do not pass through the through hole 18h in the shielding plate 18b and remain in the region R1 along the direction K1 in FIG. 3. Therefore, as shown in FIG. 9, when the potential V1 of the shielding plate 18a is negative and the potential V2 of the shielding plate 18b is positive, radicals among the plasma generated in the region R1 can selectively pass through the through hole 18h.

[0056] As shown in FIG. 10, when the potential V1 of the shielding plate 18a and the potential V2 of the shielding plate 18b are negative, positive ions pass through the through holes 18h in the shielding plate 18a and the shielding plate 18b (shielding portion 18) along the direction K2 in FIG. 3. In this case, negative ions and electrons do not pass through the through holes 18h in the shielding plate 18a and the shielding plate 18b (shielding portion 18) and remain in the region R1 along the direction K1 in FIG. 3. Therefore, as shown in FIG. 10, when the potential V1 of the shielding plate 18a and the potential V2 of the shielding plate 18b are negative, positive ions and radicals among the plasma generated in the region R1 can selectively pass through the through holes 18h.

[0057] As shown in FIG. 11, when the potential V1 of the shielding plate 18a and the potential V2 of the shielding plate 18b are positive, negative ions and electrons pass through the through holes 18h in the shielding plate 18a and the shielding plate 18b (shielding portion 18) along the direction K2 in FIG. 3. In this case, positive ions do not pass through the through holes 18h in the shielding plate 18a and the shielding plate 18b (shielding portion 18) and remain in the region R1 along the direction K1 in FIG. 3. Therefore, as shown in FIG. 11, when the potential V1 of the shielding plate 18a and the potential V2 of the shielding plate 18b are positive, negative ions and radicals among the plasma generated in the region R1 can selectively pass through the through holes 18h.

[0058] In one embodiment, the plasma processing apparatus 1 may further include an electric circuit 5. As shown in FIGS. 1 to 3, when the plasma processing apparatus 1 is a capacitively coupled plasma processing apparatus, the electric circuit 5 has a diode 5a electrically connected between the high-frequency power source 24 and the ground. The anode of the diode 5a is electrically connected to the high-frequency power source 24, and the cathode of the diode 5a is electrically connected to the ground. The electric circuit 5 is electrically connected to the high-frequency power source 24 via a matching unit 24m. The high-frequency power source 24 is electrically connected to the upper electrode 12 and is configured to generate plasma of the gas supplied from the gas supply unit 20 to the region R1 of the space S1 by applying a high-frequency voltage to the upper electrode 12. By the electric circuit 5 having the diode 5a, as shown in FIG. 6, a voltage with only a negative component is applied to the upper electrode 12 from the high-frequency power source 24 with the positive component removed. Thereby, the energy of the positive ions toward the shielding unit 18 becomes almost 0 eV, and the potential of each of the shielding plates 18a and 18b for trapping positive charged particles such as ions may be about +10V. When the electric circuit 5 is not provided, the potential of each of the shielding plates 18a and 18b for trapping charged particles such as ions is within the range of ±5V to ±500V.

[0059] FIG. 5 shows a flowchart of a plasma processing method (method MT) in one exemplary embodiment. The method MT includes steps ST1 to ST4. Step ST1 is a step of preparing a substrate W on a substrate support 16 configured to support the substrate in the space S2. Step ST2 is a step of applying a high-frequency voltage from a high-frequency power source 24 to the upper electrode 12 after step ST1. Step ST3 is a step of generating plasma of a gas supplied from a gas supply unit 20 in the space between the upper electrode 12 and the shielding unit 18 by the high-frequency voltage applied from the high-frequency power source 24 to the upper electrode 12 after step ST2. Step ST4 is a step of applying a control voltage to the shielding unit 18 after step ST3 to select ions or radicals that pass through a plurality of through holes 18h among the plasma. In this step ST4, a control voltage is applied to each of the shielding plates 18a and 18b independently of each other. Thereby, it is possible to select ions or radicals that pass through the plurality of through holes 18h of the shielding unit 18 among the plasma generated in the region R1 of the space S1.

[0060] As described above, by controlling the potentials of the shielding plates 18a and 18b, it is possible to preferably select the type (either positive or negative charged particles) of particles that pass through the through holes 18h of the shielding unit 18 and are guided to the substrate W among the plasma generated in the region R1.

[0061] For example, by setting the shielding plates 18a and 18b to potentials of the same polarity (positive or negative), it is possible to select particles that pass through the through holes 18h of the shielding unit 18 and are guided to the substrate W as radicals. Thereby, a process using radicals becomes possible.

[0062] For example, by setting the shielding plates 18a and 18b to potentials of opposite polarities (positive and negative), it is possible to select particles that pass through the through holes 18h of the shielding unit 18 and are guided to the substrate W as positive ions and either negative ions or electrons. Thereby, an anisotropic process using ions becomes possible.

[0063] Although the above-described various exemplary embodiments have been explained, various additions, omissions, substitutions, and changes may be made without being limited to the above-described exemplary embodiments. Also, it is possible to form other embodiments by combining elements in different embodiments.

[0064] For example, the plasma processing apparatus 1 according to one exemplary embodiment is not limited to the capacitively coupled plasma (CCP) type plasma processing apparatus shown in FIGS. 1 to 3. For example, it may be an inductively coupled plasma (ICP) type plasma processing apparatus shown in FIG. 12. FIG. 12 is described briefly for explanatory purposes. As shown in FIG. 12, the inductively coupled plasma processing apparatus 1 includes a coil CL and an electric circuit 5. The coil CL is electrically connected to a high-frequency power source 24 via a matcher 24m and extends along the upper electrode 12 on the upper electrode 12. The electric circuit 5 is electrically connected to the high-frequency power source 24 via the coil CL and the matcher 24m. The high-frequency power source 24 is configured to generate plasma of the gas supplied from the gas supply unit 20 to the region R1 of the space S1 by applying a high-frequency voltage to the coil CL. The electric circuit 5 has a capacitor 5b electrically connected between the high-frequency power source 24 (including the matcher 24m) and the ground. The inductively coupled plasma processing apparatus 1 shown in FIG. 12 can exhibit the same functions and achieve the same effects as the above-described capacitively coupled plasma processing apparatus 1. Also, the plasma source can be applied not only to CCP and ICP but also to microwaves.

[0065] From the above description, it will be understood that the various embodiments of the present disclosure have been described herein for the purpose of explanation and that various changes can be made without departing from the scope and gist of the present disclosure. Therefore, the various embodiments disclosed herein are not intended to be limiting, and the true scope and gist are indicated by the appended claims.

Description of Reference Numerals

[0066] 1…Plasma processing apparatus, 10…Chamber, 10s…Internal space, 12…Upper electrode, 14…Shower head, 16…Substrate support part, 16e…Lower electrode, 18…Shielding part, 18a…Shielding plate, 18b…Shielding plate, 18h…Through hole, 20…Gas supply part, 24…High-frequency power supply, 24m…Matcher, 26…DC pulse power supply, 4…Voltage application part, 40…Control part, 5…Electric circuit, 5a…Diode, 5b…Capacitor, CL…Coil, Da…Variable DC power supply, Db…Variable DC power supply, DV…DC power supply, MT…Method, OP…Amplifier, Pa…Pulse generator, Pb…Pulse generator, R1…Region, R2…Region, S1…Space, S2…Space, Vin…Input terminal, Vout…Output terminal, W…Substrate.

Claims

1. a chamber, an upper electrode, a shower head provided below the upper electrode, wherein an internal space of the chamber is divided into a first space between the upper electrode and the shower head and a second space below the shower head, and a plurality of openings are provided through the shower head to communicate the first space and the second space with each other; the shower head, a substrate support configured to support a substrate in the second space, a shielding part provided between the upper electrode and the shower head, having a first shielding plate and a second shielding plate arranged in parallel with each other along the shower head, the second shielding plate being provided on the shower head, the first shielding plate being provided on the second shielding plate, and the first shielding plate and the second shielding plate being provided with a plurality of through holes arranged to be aligned with the plurality of openings of the shower head; the shielding part, a gas supply part configured to supply gas to a region in the first space between the upper electrode and the shielding part, a high-frequency power supply configured to output a high-frequency voltage to generate plasma of the gas, a voltage application part configured to select, from among species of only radicals, species of only the radicals and positive ions, and species of only the radicals and negative ions, species of the plasma that pass through the plurality of through holes by applying a control voltage to the shielding part, a control part configured to control the voltage application part, comprising, the voltage application part is configured to independently apply a control voltage to each of the first shielding plate and the second shielding plate according to control received from the control part, the control part controls the voltage application part such that an absolute value of the control voltage applied to the second shielding plate is equal to or greater than an absolute value of the control voltage applied to the first shielding plate, a plasma processing apparatus.

2. each of the first shielding plate and the second shielding plate includes a metal plate coated with an insulating coating, the voltage application part has a first pulse generator, a second pulse generator, a first variable DC power supply, and a second variable DC power supply, the first pulse generator and the second pulse generator are configured to output a rectangular-wave control voltage, the first shielding plate, the first pulse generator, and the first variable DC power supply are electrically connected in series in this order, The second shielding plate, the second pulse generator, and the second variable DC power supply are electrically connected in series in this order. The control unit controls the voltage application unit so as to apply rectangular control voltages having opposite phases to each of the first shielding plate and the second shielding plate. The plasma processing apparatus according to claim 1.

3. Each of the first shielding plate and the second shielding plate includes a metal plate that is not insulated. The voltage application unit has a first variable DC power supply and a second variable DC power supply. The first shielding plate and the first variable DC power supply are electrically connected in series in this order. The second shielding plate and the second variable DC power supply are electrically connected in series in this order. The control unit controls the voltage application unit so as to apply a DC control voltage to each of the first shielding plate and the second shielding plate. The plasma processing apparatus according to claim 1.

4. It further includes an electric circuit electrically connected to the high-frequency power supply. The high-frequency power supply is electrically connected to the upper electrode, and generates plasma of the gas by applying a high-frequency voltage to the upper electrode. The electric circuit has a diode electrically connected between the high-frequency power supply and the ground. The anode of the diode is electrically connected to the high-frequency power supply, and the cathode of the diode is electrically connected to the ground. The plasma processing apparatus according to any one of claims 1 to 3.

5. A plasma processing method for processing a substrate using a plasma processing apparatus, The plasma processing apparatus is A shower head provided below the upper electrode, wherein the internal space of the chamber is divided into a first space between the upper electrode and the shower head and a second space below the shower head, and a plurality of openings penetrating the shower head are provided to communicate the first space and the second space with each other. The shower head, A shielding portion provided between the upper electrode and the shower head, having a first shielding plate and a second shielding plate arranged in parallel with each other along the shower head, the second shielding plate being provided on the shower head, the first shielding plate being provided on the second shielding plate, and a plurality of through holes provided so that the first shielding plate and the second shielding plate are aligned with the plurality of openings of the shower head. The shielding portion, A high-frequency power supply configured to output a high-frequency voltage for generating plasma of a gas supplied from a gas supply unit to a region within the first space; having; The method includes: preparing a substrate on a substrate support configured to support the substrate within the second space; applying a high-frequency voltage to the upper electrode; generating plasma in a space between the upper electrode and the shielding portion by the high-frequency voltage; applying a control voltage to the shielding portion to select chemical species that pass through the plurality of through-holes among the plasma from among chemical species that are only radicals, chemical species that are only the radicals and positive ions, and chemical species that are only the radicals and negative ions; comprising; In the step of applying the control voltage, the control voltage is applied independently to each of the first shielding plate and the second shielding plate such that the absolute value of the control voltage applied to the second shielding plate is equal to or greater than the absolute value of the control voltage applied to the first shielding plate; a plasma processing method.

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