Plasma processing equipment

Abstract

To provide a plasma processing method and a plasma processing apparatus, capable of improving the etching selectivity of a silicon-containing film relative to a mask.SOLUTION: A method includes steps of: a) providing a substrate including a silicon-containing film and a mask on the silicon-containing film, on a substrate support in a plasma processing chamber; b) supplying a process gas; c) periodically supplying a pulse voltage to the substrate support; and d) periodically supplying RF power and generating plasma by the RF power to etch the silicon-containing film. A first period P1 in which a first pulse voltage having a negative polarity is supplied and a second period P2 in which the pulse voltage having a negative polarity is not supplied or a second pulse voltage whose absolute value is less than an absolute value of the first pulse voltage is supplied are repeated in c). A third period T1 in which first RF power is supplied and a fourth period T2 in which the RF power is not supplied or second RF power less than the first RF power is supplied are repeated in d). The first period starts before a start of the third period.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] A plasma processing apparatus is used for plasma processing of a substrate. The plasma processing apparatus includes a chamber and a substrate-holding electrode. The substrate-holding electrode is provided in the chamber. The substrate-holding electrode holds a substrate placed on its main surface. One type of such a plasma processing apparatus is described, for example, in Patent Document 1.

[0003] The plasma processing apparatus described in Patent Document 1 further includes a radio frequency generator and a DC negative pulse generator. The radio frequency generator supplies a radio frequency voltage to a substrate holding electrode. In the plasma processing apparatus described in Patent Document 1, the radio frequency voltage is alternately switched on and off. In addition, in the plasma processing apparatus described in Patent Document 1, a negative pulse voltage (DC) is supplied to the substrate holding electrode from the DC negative pulse generator in accordance with the timing of the on and off of the radio frequency voltage. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-187975 Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure provides a technique capable of improving the etching selectivity, defined as the ratio of the etching rate of a silicon-containing film to the etching rate of a mask, in plasma processing of a substrate. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, there is provided a plasma processing method comprising: (a) providing a substrate having a silicon-containing film on a substrate support in a plasma processing chamber and a mask on the silicon-containing film; (b) supplying a processing gas into the plasma processing chamber; (c) periodically supplying a pulse voltage to the substrate support; and (d) periodically supplying RF power to generate plasma from the processing gas using the RF power to etch the silicon-containing film, wherein the pulse voltage has a negative polarity; (c) repeats a first period in which a first pulse voltage is supplied and a second period in which the negative pulse voltage is not supplied or a second pulse voltage having an absolute value smaller than the first pulse voltage is supplied; and (d) repeats a third period in which a first RF power is supplied and a fourth period in which the RF power is not supplied or a second RF power smaller than the first RF power is supplied, wherein the first period starts before the third period starts. [Effects of the Invention]

[0007] According to one aspect, the etching selectivity can be improved in plasma processing of a substrate. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of the film structure of a substrate processed according to one embodiment of the present disclosure. [Figure 2] FIG. 2 is a timing chart showing the timing of supplying RF power and the timing of supplying a bias voltage (negative pulse voltage) in a plasma processing method according to one embodiment of the present disclosure. [Figure 3] FIG. 3 is a timing chart showing an example of the supply timing of RF power and bias voltage in an embodiment of a plasma processing method according to an aspect of the present disclosure. [Figure 4] FIG. 4 is a time chart showing the timing of supplying RF power and bias voltage in the plasma processing method of the reference example. [Figure 5] FIG. 5 is a diagram illustrating an example of the configuration of a plasma processing system. [Figure 6] FIG. 6 is a diagram illustrating an example of the configuration of a capacitively coupled plasma processing apparatus. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant explanations may be omitted.

[0010] In this specification, deviations in directions such as parallel, right angles, orthogonal, horizontal, vertical, up / down, left / right, etc. are permitted to the extent that they do not impair the effects of the embodiments. The shape of the corners is not limited to right angles and may be rounded like an arch. Parallel, right angles, orthogonal, horizontal, vertical, and circular may also include approximately parallel, approximately right angles, approximately orthogonal, approximately horizontal, approximately vertical, and approximately circular.

[0011] [Substrate film structure] 1 is a schematic diagram of a film structure on a substrate to be processed according to one embodiment of the present disclosure. The substrate W has an etching target film EL and a mask MK on the etching target film EL. Hole-shaped or line-shaped recesses Re are formed in the mask MK, and the etching target film EL is etched to the shape of the recesses Re.

[0012] The etching target film EL may be, for example, a silicon-containing film. The silicon-containing film may be a silicon oxide film, a silicon nitride film, a silicon germanium film, a silicon carbide film, or a laminated film containing two or more of these films. However, the silicon-containing film is preferably a silicon oxide film or a laminated film of a silicon oxide film and a silicon nitride film.

[0013] The mask MK may be a polysilicon film, a boron-doped silicon film, an organic film, or a tungsten-containing film, which may be a tungsten silicide film or a tungsten boron carbide film.

[0014] [Plasma treatment method] In one embodiment of the present disclosure, a plasma processing method for a substrate W etches an etching target film EL selectively with respect to a mask MK. In one example, the etching target film EL may be a silicon-containing film. In one example, the mask MK is disposed on the silicon-containing film. The method includes the following steps (a) to (d): (a) providing a substrate having a silicon-containing film on a substrate support in a plasma processing chamber and a mask on the silicon-containing film; (b) supplying a process gas into the plasma processing chamber; (c) periodically applying a negative pulse voltage to the substrate support; (d) periodically supplying RF (Radio Frequency) power to generate plasma from the processing gas by the RF power, thereby etching the silicon-containing film;

[0015] (a: Step of providing a substrate) In the step (a) of providing a substrate, a substrate W having a film structure such as that shown in FIG. 1 is provided on a substrate support 11 (see FIG. 6) arranged in a plasma processing chamber 10 of a plasma processing apparatus 1 described later.

[0016] (b: Process of supplying processing gas) In the process of supplying the processing gas (b), the processing gas is supplied into the plasma processing chamber 10 from a shower head 13 (see FIG. 6) described later.

[0017] 2 is a time chart showing an example of the timing of supplying (A) RF power and (B) bias voltage in a plasma processing method according to one embodiment of the present disclosure. In one embodiment of the present disclosure, after a substrate W is provided, (B) bias voltage is supplied in step (c) as shown in FIG. 2, and (A) RF power is supplied in step (d).

[0018] (c: Step of supplying a negative pulse voltage) In the step (c) of supplying a negative pulse voltage, a negative pulse voltage (a pulse voltage having negative polarity) (hereinafter also referred to as "bias voltage") is periodically supplied to the bias electrode of the substrate support 11. "Periodicity" here refers to both the on-off periodicity within a first period P1, which will be described later, and the periodicity between the on state of the pulse wave in the first period P1 and the off state in the second period P2. The bias electrode may be a lower electrode (base 1110, see FIG. 6) that supports the substrate support 11, or may be an electrode 1112b (see FIG. 6) disposed within the substrate support 11. The substrate support 11 may be, for example, an electrostatic chuck 1111 (see FIG. 6).

[0019] In FIG. 2B, as an example, the bias voltage is cycled through a first period P1 during which a negative pulse voltage is supplied in response to the "high" and "low" timings of the RF power shown in FIG. 2A, and a second period P2 during which the supply of the negative pulse voltage is stopped, in this order. The period during which the RF power is "high" is designated as a third period T1, and the period during which the RF power is "low" is designated as a fourth period T2. The bias voltage supply starts before the start of the third period T1 (before time t). The supply of the negative pulse voltage is stopped at or before the end of the third period T1. The third period T1 is a period during which a first RF power is supplied, and the fourth period T2 is a period during which no RF power is supplied or a second RF power smaller than the first RF power is supplied. The supply period P1 of the negative pulse voltage is an example of a first period during which the first pulse voltage is supplied. The supply stop period P2 of the negative pulse voltage is an example of a second period during which no pulse voltage is supplied or a second pulse voltage whose absolute value is smaller than the first pulse voltage is supplied. As will be described later, in the second period, no pulse voltage may be supplied, or a second pulse voltage smaller than the first pulse voltage may be supplied.

[0020] During the first period P1 in which a negative pulse voltage is supplied, the bias voltage periodically alternates between an on state (on: negative value) and an off state (off: 0V). During the second period P2, the bias voltage is in an off state. When the bias voltage is in an on state, it indicates that a bias voltage is being supplied to the bias electrode. On the other hand, when the bias voltage is in an off state, it indicates that no bias voltage is being supplied to the bias electrode (the bias voltage is 0V).

[0021] During the first period P1 in which the negative pulse voltage is supplied, the first frequency f1 is the reciprocal of the on-off cycle (wavelength λ1) of the negative pulse voltage supplied to the bias electrode. The first frequency f1 of the bias voltage may be 100 kHz or more and 3.2 MHz or less. In one example, the first frequency f1 is set to 400 kHz.

[0022] Furthermore, the duty ratio of the bias voltage of the first frequency f1 during the first period P1 is defined as the first duty ratio. The first duty ratio indicates the ratio of the on time of the pulse voltage, and is the ratio of the on time to the total time of the on time and off time of the bias voltage during the first period P1 (on time / (on time + off time)). The first duty ratio may be 30% or less, or 20% or less. The negative pulse voltage may have a pulse waveform such as a square wave, a triangular wave, an impulse wave, a trapezoidal wave, or a combination thereof.

[0023] In one embodiment of the present disclosure, a first period P1 during which a negative pulse voltage is supplied and a second period P2 during which the supply is stopped are periodically repeated. If the frequency f2 is the reciprocal of the period (wavelength λ2) between the first period P1 and the second period P2, the second frequency f2 of the bias voltage may be 0.1 kHz or more and 20 kHz or less. If the duty ratio of the pulse waveform of the bias voltage at the second frequency f2 is the second duty ratio, the second duty ratio may be 40% or less. The second duty ratio indicates the proportion of the first period, i.e., the proportion of the first period P1 to the total time of (first period P1 + second period P2). The absolute value of the amplitude of the negative pulse voltage may be 0.5 kV or more and 20 kV or less.

[0024] (d: Process of etching the substrate) In the step (d) of etching the silicon-containing film on the substrate, plasma generated from the processing gas by RF power is used to etch the silicon-containing film on the substrate W. The RF power is supplied to the substrate support 11. However, the RF power may also be supplied to the shower head 13 facing the substrate support 11.

[0025] The frequency of the RF power may be in the range of 27 MHz to 100 MHz, for example, 40 MHz or 60 MHz. The processing gas is selected depending on the type of film EL to be etched. When the film EL to be etched is a silicon oxide film, for example, a fluorine-containing gas can be used as the processing gas. The fluorine-containing gas can be, for example, a fluorocarbon gas or nitrogen trifluoride gas. Furthermore, an oxygen-containing gas and / or an inert gas may be added to the processing gas.

[0026] In (A) of FIG. 2, "low" indicates that no RF power is supplied (RF power is 0 W) or that the RF power is a first RF power whose magnitude is greater than 0 W. For example, the first RF power may be less than 1 kW, may be 500 W or less, or may be 50 W or less. On the other hand, "high" indicates that the RF power is a second RF power whose magnitude is greater than the first RF power. For example, the second RF power may be 1 kW or more and 10 kW or less.

[0027] In the etching step (d), a third period T1 in which the RF power is controlled to "high" and a fourth period T2 in which the RF power is controlled to "low" are repeated in this order. By supplying RF power, plasma is generated from the processing gas to etch the silicon-containing film EL on the substrate W.

[0028] In the step (c) of supplying a negative pulse voltage, the supply of the bias voltage begins a time t before the start of the third period T1. The time t may be 1 μsec or more and 20 μsec or less. In this case, the first period P1 begins 1 μsec or more and 20 μsec or less before the start of the third period T1. The time t is more preferably 3 μsec or more and 14 μsec or less. In this case, the first period P1 begins 3 μsec or more and 14 μsec or less before the start of the third period T1. The time t is particularly preferably 5 μsec or more and 10 μsec or less. In this case, the first period P1 begins 5 μsec or more and 10 μsec or less before the start of the third period T1.

[0029] In step (c), assuming that one on-state waveform included for each wavelength λ1 of the pulse voltage is one waveform, the number of waves of the pulse voltage included in time t, i.e., the period from the start of the first period P1 to the start of the third period T1, may be 1 to 6. For example, in Fig. 2, the number of waves of the pulse voltage included in time t is 3, and in Fig. 3 described below, the number of waves of the pulse voltage included in time t is 6.

[0030] According to the plasma processing method of the present disclosure, the etching rate can be improved by controlling the start of supplying the bias voltage to a time t before the start of the third period T1. Furthermore, the etching selectivity, defined as the ratio (Ve / Vm) of the etching rate Ve of the silicon-containing film EL to the etching rate Vm of the mask MK, can be improved by 40% or more. An evaluation experiment demonstrating these effects will be described below.

[0031] [Example] An example of the plasma processing method according to the embodiment of the present disclosure will be described below in comparison with a reference example. Fig. 3 is a time chart showing the supply timing of (A) RF power and (B) bias voltage in the example of the plasma processing method according to the embodiment of the present disclosure. Fig. 4 is a time chart showing the supply timing of (A) RF power and (B) bias voltage in the plasma processing method of the reference example.

[0032] In this evaluation experiment, a substrate W as shown in Fig. 1 was used. Specifically, in both the example and the reference example, the substrate W used had an etching target film EL made of a silicon oxide film and a mask MK made of a polysilicon film.

[0033] In both the example and the reference example, the processing conditions in the evaluation experiments were the same, and the plasma processing was performed on the substrate W under the processing conditions shown below. <Processing conditions in evaluation experiments> Pressure in plasma processing chamber: 10 mTorr (1.33 Pa) Processing gases: C4F6 gas, C4F8 gas, NF3 gas, O2 gas RF power: 40MHz, high: 5.5kW, low: 0kW Negative pulse voltage: -8.0kV, pulse wave (triangle wave) First frequency f1: 400kHz, First duty ratio: 17% Second frequency f2: 3kHz, second duty ratio: 20% ·Time t: 14μsec

[0034] In the plasma processing method of the embodiment in Figure 3, a negative pulse voltage was supplied to the bias electrode at time t before the start of the third period T1, and in the plasma processing method of the reference example in Figure 4, the same processing was performed except that a negative pulse voltage was supplied to the bias electrode simultaneously with the start of the third period T1.

[0035] As a result of the experiment, when the plasma processing method of the reference example was performed, the etching rate of the silicon oxide film was 80 (nm / min) and the etching selectivity ratio was 1.7. On the other hand, when the plasma processing method of the example was performed, the etching rate of the silicon oxide film was 110 (nm / min) and the etching selectivity ratio was 2.4. From the above, according to the plasma processing method of the example, the etching rate and etching selectivity ratio could be improved by 40% or more compared to the plasma processing method of the reference example.

[0036] 3 and the reference example of the plasma processing method of FIG. 4, a negative pulse voltage is supplied to the bias electrode when the RF power is in the high state during the third period T1. Ions in the plasma generated when the pulse voltage is off are attracted to the substrate W by the negative voltage supplied to the bias electrode when the pulse voltage is on, thereby accelerating etching.

[0037] However, in the plasma processing method of the reference example, the supply of negative pulse power to the bias electrode started simultaneously with the start of the third period T1. As shown in FIG. 4, a decrease in the amplitude of the negative pulse power was observed immediately after the supply.

[0038] On the other hand, in the plasma processing method of the example, as shown in Figure 3, by starting the supply of the negative pulse voltage before time t before the start of the third period T1, it was possible to prevent a decrease in the amplitude of the negative pulse power immediately after supply. Therefore, in the plasma processing method of the example, the plasma was more stable than in the plasma processing method of the reference example, which is thought to have improved the etching rate and further promoted etching. Furthermore, it is thought that the stabilization of the plasma suppressed peeling of the mask MK during the fourth period T2, improving the etching selectivity.

[0039] Although the above description has been given with reference to a negative pulse voltage, this is not limiting. In one embodiment, the pulse voltage is a voltage generated by waveform shaping using a waveform shaper on a DC voltage generated by a DC power supply 32 (see FIG. 6 ), which will be described later. The pulse voltage may have a pulse waveform such as a square wave, a triangular wave, an impulse wave, a trapezoidal wave, an arbitrary waveform, or a combination thereof. The pulse voltage is periodically supplied to the substrate support 11. The polarity of the pulse voltage may be negative or positive, as long as the potential of the substrate W is set so as to create a potential difference between the plasma and the substrate W and attract ions to the substrate W.

[0040] In addition to the above description, the following items are further disclosed.

[0041] a) providing a substrate having a silicon-containing film and a mask on a substrate support in a plasma processing chamber; b) supplying a process gas into the plasma processing chamber; c) periodically applying a pulse voltage to the substrate support; d) periodically supplying RF power to generate plasma from the processing gas by the RF power to etch the silicon-containing film; Equipped with the pulse voltage is supplied to the substrate support part so as to generate a potential difference between the plasma and the substrate; the step c) repeats a first period in which a first pulse voltage is supplied and a second period in which the pulse voltage is not supplied or a second pulse voltage smaller than the first pulse voltage is supplied; the step d) repeats a third period in which a first RF power is supplied and a fourth period in which no RF power is supplied or a second RF power smaller than the first RF power is supplied; the first time period begins before the third time period begins; Plasma treatment method.

[0042] [Plasma processing system] Next, an example of a plasma processing system and a plasma processing apparatus capable of performing a plasma processing method according to an embodiment of the present disclosure will be described. Fig. 5 is a diagram illustrating an example of the configuration of a plasma processing system.

[0043] As shown in FIG. 5, 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 10s (see FIG. 6). The plasma processing chamber 10 also has at least one gas supply port 13a (see FIG. 6) for supplying at least one processing gas to the plasma processing space 10s and at least one gas exhaust port 10e (see FIG. 6) for exhausting gas from the plasma processing space 10s. The gas supply port 13a is connected to a gas supply unit 20 (described later), and the gas exhaust port 10e 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 W (see FIG. 6).

[0044] The plasma generating unit 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma formed in the plasma processing space may be capacitively coupled plasma (CCP), inductively coupled plasma (ICP), electron-cyclotron-resonance plasma (ECR plasma), helicon wave plasma (HWP), or surface wave plasma (SWP). Various types of plasma generating units may be used, including alternating current (AC) plasma generating units and direct current (DC) plasma generating units. In one embodiment, the AC signal (AC power) used in the AC plasma generating unit has a frequency in the range of 100 kHz to 10 GHz. Therefore, the AC signal includes a radio frequency (RF) signal and a microwave signal. In one embodiment, the RF signal has a frequency in the range of 100 kHz to 150 MHz.

[0045] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to perform various processes described in this disclosure. The control unit 2 may be configured to control each element of the plasma processing apparatus 1 to perform 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 may be implemented by, for example, a computer 2a. The processing unit 2a1 may be configured to read a program from the storage unit 2a2 and execute the read program to perform various control operations. The program may be stored in the storage unit 2a2 in advance or may be acquired via a medium when needed. The acquired program is stored in the storage unit 2a2 and read from the storage unit 2a2 by the processing unit 2a1 for execution. The medium may be various storage media readable by the computer 2a or 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).

[0046] The following describes a configuration example of a capacitively coupled plasma processing apparatus as an example of the plasma processing apparatus 1. Fig. 6 is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus.

[0047] The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply 20, a power supply 30, 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 a plasma processing space 10s defined by the showerhead 13, a sidewall 10a of the plasma processing chamber 10, and the substrate support 11. The plasma processing chamber 10 is grounded. The showerhead 13 and the substrate support 11 are electrically insulated from the housing of the plasma processing chamber 10.

[0048] 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.

[0049] In one embodiment, the main body 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive member. The conductive member of the base 1110 can function as a lower electrode. The electrostatic chuck 1111 is disposed on the base 1110. The electrostatic chuck 1111 includes a ceramic member 1111a in a central region 111a and an electrostatic electrode 1111b disposed within the ceramic member 1111a. The ceramic member 1111a has the central region 111a. In one embodiment, the ceramic member 1111a also has an annular region 111b. Note that another member surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member, may also have the annular region 111b. In this case, the ring assembly 112 may be disposed on the annular electrostatic chuck or the annular insulating member, or may be disposed on both the electrostatic chuck 1111 and the annular insulating member. Furthermore, at least one RF / DC electrode coupled to an RF power supply 31 and / or a DC power supply 32 (described later) may be disposed within the ceramic member 1111a. In this case, the at least one RF / DC electrode functions as a lower electrode. When a bias RF signal and / or a DC signal (described later) is supplied to the at least one RF / DC electrode, the RF / DC electrode is also referred to as a bias electrode. Below the electrostatic electrode 1111b, an electrode 1112b is embedded in the electrostatic chuck 1111 and is disposed parallel to the electrostatic electrode 1111b. The electrode 1112b is an example of a bias electrode. Note that the conductive member of the base 1110 and the at least one RF / DC electrode may function as multiple lower electrodes. Alternatively, the electrostatic electrode 1111b may function as the lower electrode. Therefore, the substrate support 11 includes at least one lower electrode.

[0050] 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.

[0051] 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.

[0052] In one embodiment, the ceramic member 1111a also has an annular region 111b. The electrostatic chuck 1111 may include the ceramic member 1111a in the annular region 111b and an electrostatic electrode 1113a disposed within the ceramic member 1111a. An electrode 1113b may be disposed below the electrostatic electrode 1113a and parallel to the electrostatic electrode 1113a. The electrode 1113b is an example of a bias electrode.

[0053] The showerhead 13 is configured to introduce at least one processing gas from the gas supply unit 20 into the plasma processing space 10s. The showerhead 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and multiple gas inlets 13c. The processing gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the plasma processing space 10s from the multiple gas inlets 13c. The showerhead 13 also includes at least one upper electrode. In addition to the showerhead 13, the gas introduction unit may also include one or more side gas injectors (SGIs) attached to one or more openings formed in the sidewall 10a.

[0054] 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 process gas from a corresponding gas source 21 to the showerhead 13 via a corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, the gas supply unit 20 may include at least one flow modulation device that modulates or pulses the flow rate of the at least one process gas.

[0055] The power supply 30 includes an RF power supply 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply 31 is configured to supply at least one RF signal (RF power) to at least one lower electrode and / or at least one upper electrode. This generates a plasma from at least one processing gas supplied to the plasma processing space 10s. Therefore, the RF power supply 31 can function as at least a part of the plasma generation unit 12. Furthermore, by supplying a bias RF signal to the at least one lower electrode, a bias potential is generated on the substrate W, and ion components in the formed plasma can be attracted to the substrate W.

[0056] In one embodiment, the RF power supply 31 includes a first RF generating unit 31a and a second RF generating unit 31b. The first RF generating unit 31a is coupled to at least one lower electrode and / or at least one upper electrode via at least one impedance matching circuit and is configured to generate a source RF signal (source RF power) for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 10 MHz to 150 MHz. In one embodiment, the first RF generating unit 31a may be configured to generate multiple source RF signals having different frequencies. The generated one or more source RF signals are supplied to at least one lower electrode and / or at least one upper electrode.

[0057] The second RF generating unit 31b is coupled to at least one lower electrode via at least one impedance matching circuit and configured to generate a bias RF signal (bias RF power). The frequency of the bias RF signal may be the same as or different from the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency lower than the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 100 kHz to 60 MHz. In one embodiment, the second RF generating unit 31b may be configured to generate multiple bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to at least one lower electrode. In various embodiments, the source RF signal supplies RF power (A), examples of which are shown in FIGS. 2 and 3.

[0058] The power supply 30 may also include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generator 32a and a second DC generator 32b. In one embodiment, the first DC generator 32a is connected to at least one lower electrode and configured to generate a first DC signal. The generated first DC signal is provided to the at least one lower electrode. In one embodiment, the second DC generator 32b is connected to at least one upper electrode and configured to generate a second DC signal. The generated second DC signal is provided to the at least one upper electrode.

[0059] In various embodiments, the first DC signal is pulsed. The first DC signal supplies a bias voltage (B), an example of which is shown in FIGS. 2 and 3 . The second DC signal may also be pulsed. In this case, a sequence of pulsed voltages is supplied to at least one lower electrode and / or at least one upper electrode. In one embodiment, a waveform shaper 32c for generating a sequence of pulsed voltages from the DC signal is connected between the first DC generator 32a and at least one lower electrode. Therefore, the first DC generator 32a and the waveform shaper 32c constitute a voltage pulse generator. The pulsed voltage is a voltage generated by waveform shaping the DC voltage generated by the first DC generator 32a using the waveform shaper 32c. The pulsed voltage may have a pulse waveform such as a square wave, a triangular wave, an impulse waveform, a trapezoidal wave, or a combination thereof. The pulsed voltage does not have to be a negative DC voltage as long as it is supplied to the substrate support 11 so as to generate a potential difference between the plasma and the substrate W. That is, the pulse voltage shaped by the waveform shaper 32c may be negative or positive as long as the potential of the substrate W is set so as to create a potential difference between the plasma and the substrate W and attract ions to the substrate W.

[0060] When the second DC generating unit 32b and the waveform shaping unit constitute a voltage pulse generating unit, the voltage pulse generating unit is connected to at least one upper electrode. The voltage pulse may have a positive polarity or a negative polarity. Furthermore, a voltage pulse sequence may include one or more positive voltage pulses and one or more negative voltage pulses within one cycle. The first and second DC generating units 32a and 32b may be provided in addition to the RF power supply 31, or the first DC generating unit 32a may be provided instead of the second RF generating unit 31b. In this embodiment, the first DC generating unit 32a is provided instead of the second RF generating unit 31b.

[0061] The exhaust system 40 may be connected to, for example, a gas exhaust port 10e provided at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure regulating valve regulates the pressure in the plasma processing space 10s. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0062] As described above, the plasma processing method and plasma processing apparatus of this embodiment can improve the etching selectivity and the etching rate.

[0063] The plasma processing method and plasma processing apparatus according to the presently disclosed embodiments should be considered to be illustrative in all respects and not restrictive. The embodiments can be modified and improved in various ways without departing from the spirit and scope of the appended claims. The features described in the above embodiments can be configured in other ways as long as they are not inconsistent, and can be combined as long as they are not inconsistent.

[0064] This application claims priority to U.S. Provisional Application No. 63 / 123,824, filed in the United States Patent and Trademark Office on December 10, 2020, the entire contents of which are incorporated herein by reference. [Explanation of symbols]

[0065] 1. Plasma processing equipment 2. Control Unit 2a Computer 2a1 Processing section 2a2 Storage section 2a3 communication interface 10 Plasma Processing Chamber 11 Substrate support 13. Shower head 21 Gas Source 20 Gas supply unit 30 power supply 31 RF power supply 32 DC power supply 32c waveform shaper 40 Exhaust system 111 Main body 112 Ring Assembly

Claims

1. A plasma processing chamber; a substrate support disposed within the plasma processing chamber and having a lower electrode; an upper electrode disposed above the substrate support; a voltage pulse generator connected to the bottom electrode and configured to generate a voltage pulse signal, the voltage pulse signal having a sequence of a plurality of voltage pulses during a first sub-period within a repeat period and having an off state during a second sub-period within the repeat period; and an RF power supply connected to the upper electrode or the lower electrode and configured to generate an RF signal, the RF signal having a first power level during a delay period within the first sub-period, a second power level during the first sub-period excluding the delay period, and the first power level during the second sub-period, wherein the delay period is in a range of 1 μsec to 20 μsec, Plasma processing equipment.

2. A chamber; a substrate support disposed within the chamber and having a lower electrode; a voltage pulse generator connected to the bottom electrode and configured to generate a voltage pulse signal, the voltage pulse signal having a sequence of a plurality of voltage pulses during a first sub-period within a repeat period and having an off state during a second sub-period within the repeat period; and an RF power supply configured to generate an RF signal to generate a plasma in the chamber, the RF signal having a first power level during a delay period within the first sub-period, a second power level during the first sub-period excluding the delay period, and the first power level during the second sub-period, the delay period being in a range of 1 μsec to 20 μsec, Plasma processing equipment.

3. The first power level is less than the second power level.

3. A plasma processing apparatus comprising: a processing chamber for processing a plasma;

4. The voltage pulse has negative polarity, and the absolute value of the voltage of the voltage pulse is 0.5 kV or more and 20 kV or less. The plasma processing apparatus according to any one of claims 1 to 3.

5. The voltage pulse is a DC voltage waveform shaped and supplied to the substrate support part. The plasma processing apparatus according to claim 1 .

6. The delay period is in the range of 3 μsec to 14 μsec. The plasma processing apparatus according to claim 1 .

7. The delay period is in the range of 5 μsec to 10 μsec. The plasma processing apparatus according to claim 1 .

8. the number of waves of the voltage pulse included in the delay period is 1 or more and 6 or less; The plasma processing apparatus according to claim 1 .

9. a first frequency, which is the reciprocal of the on-off cycle of the voltage pulse, is equal to or higher than 100 kHz and equal to or lower than 3.2 MHz; The plasma processing apparatus according to claim 1 .

10. a first duty ratio indicating a ratio of an on-time of the voltage pulse is 30% or less; The plasma processing apparatus according to claim 9 .

11. the first duty ratio is 20% or less; The plasma processing apparatus according to claim 10.

12. a second frequency, which is the reciprocal of the period between the first sub-period and the second sub-period, is equal to or greater than 0.1 kHz and equal to or less than 20 kHz; The plasma processing apparatus according to claim 1 .

13. a second duty ratio indicating a ratio of the first sub-period is 40% or less; The plasma processing apparatus according to claim 12 .

14. The voltage pulse has a pulse waveform of a square wave, a triangular wave, an impulse wave, a trapezoidal wave, or a combination thereof. The plasma processing apparatus according to claim 1 .

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