Plasma processing apparatus and etching method

Abstract

The present invention provides a plasma processing apparatus and a plasma processing method that improve the performance of removing residue. [Solution] The plasma processing apparatus method comprises a first RF generation unit 31a that supplies a first RF signal to an antenna 14, a second RF generation unit 32b that supplies a second RF signal to a bias electrode, a third RF generation unit 31c that supplies a third RF signal to a bias electrode, and a control unit 2. The control unit performs the following steps: supplying a first RF signal at a first power level to the antenna and supplying a second RF signal at a third power level to the bias electrode; supplying a third RF signal at a fifth power level to the bias electrode; supplying a second RF signal at a fourth power level to the bias electrode; exhausting gas in the plasma processing space; and supplying a first RF signal at a second power level to the antenna and supplying a third RF signal at a sixth power level to the bias electrode.

Description

Technical Field

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

Background Art

[0002] Patent Documents 1 and 2 disclose a plasma processing apparatus and a plasma processing method for improving the performance of a process using a plurality of high-frequency power pulse signals.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In one aspect, the present disclosure provides a plasma processing apparatus and a plasma processing method for improving the residue removal performance.

Means for Solving the Problems

[0005] To solve the above problems, according to one embodiment, a plasma processing chamber having a plasma processing space, an antenna, a substrate support portion disposed in the plasma processing chamber and having a bias electrode and supporting a substrate, a gas introduction portion for supplying processing gas into the plasma processing space, a first RF generation unit for supplying a first RF signal to the antenna, a second RF generation unit for supplying a second RF signal to the bias electrode, a third RF generation unit for supplying a third RF signal to the bias electrode, an exhaust system for adjusting the pressure in the plasma processing space, and a control unit, wherein the control unit supplies the first RF signal of a first power level to the antenna A plasma processing apparatus can be provided that is configured to perform the following steps: supplying power to the antenna and supplying the second RF signal at the third power level to the bias electrode; supplying the third RF signal at the fifth power level to the bias electrode; supplying the second RF signal at the fourth power level to the bias electrode; exhausting the gas in the plasma processing space; supplying the first RF signal at the second power level to the antenna and supplying the third RF signal at the sixth power level to the bias electrode; and supplying the third RF signal at the sixth power level to the bias electrode. [Effects of the Invention]

[0006] In one respect, it is possible to provide a plasma processing apparatus and a plasma processing method that improve the performance of removing residue. [Brief explanation of the drawing]

[0007] [Figure 1] An example of a diagram illustrating the configuration of a plasma processing system. [Figure 2] An example of a diagram illustrating the configuration of an inductively coupled plasma processing apparatus. [Figure 3] A flowchart illustrating an example of plasma etching. [Figure 4] A time chart showing an example of plasma etching. [Figure 5] An example of a schematic cross-sectional view of a circuit board. [Figure 6] An example of a schematic cross-sectional view of a circuit board. [Modes for carrying out the invention]

[0008] Various exemplary embodiments will be described in detail below with reference to the drawings. In each drawing, the same or corresponding parts will be denoted by the same reference numerals.

[0009] [Plasma Processing System] Figure 1 is an example diagram illustrating an example configuration of a plasma processing system. In one embodiment, the plasma processing system includes a plasma processing apparatus 1 and a control unit 2. The plasma processing system is an example of a substrate processing system, and the plasma processing apparatus 1 is an example of a substrate processing apparatus. The plasma processing apparatus 1 includes a plasma processing chamber 10, a substrate support unit 11, and a plasma generation unit 12. The plasma processing chamber 10 has a plasma processing space. The plasma processing chamber 10 also has at least one gas supply port for supplying at least one processing gas to the plasma processing space, and at least one gas outlet for discharging gas from the plasma processing space. The gas supply port is connected to a gas supply unit 20, which will be described later, and the gas outlet is connected to an exhaust system 40, which will be described later. The substrate support unit 11 is located in the plasma processing space and has a substrate support surface for supporting a substrate.

[0010] The plasma generation unit 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma formed in the plasma processing space may be a capacitively coupled plasma (CCP), an inductively coupled plasma (ICP), an electron cyclotron resonance (ECR) plasma, a helicon wave excited plasma (HWP), or a surface wave plasma (SWP), etc. Various types of plasma generation units, including an AC (alternating current) plasma generation unit and a DC (direct current) plasma generation unit, may also be used. In one embodiment, the AC signal (AC power) used in the AC plasma generation unit has a frequency in the range of 100 kHz to 10 GHz. Therefore, the AC signal includes an RF (radio frequency) signal and a microwave signal. In one embodiment, the RF signal has a frequency in the range of 100 kHz to 150 MHz.

[0011] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to perform the various processes described herein. The control unit 2 may be configured to control each element of the plasma processing apparatus 1 to perform the various processes described herein. In one embodiment, some or all of the control unit 2 may be included in the plasma processing apparatus 1. The control unit 2 is implemented, for example, by a computer 2a. The control unit 2 may include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The functions implemented by the processing unit 2a1 described herein may be implemented in a circuit or processing circuitry, including a general-purpose processor, an application-specific processor, integrated circuits, ASICs (Application Specific Integrated Circuits), a CPU (Central Processing Unit), conventional circuitry, and / or a combination thereof, programmed to implement the functions described herein. A processor is considered a circuit or processing circuit, including transistors and other circuitry. A processor may be a programmed processor that executes a program stored in the storage unit 2a2. This program may be stored in the memory unit 2a2 in advance, or it may be retrieved via a medium when needed. The retrieved program is stored in the memory unit 2a2 and read from the memory unit 2a2 and executed by the processing unit 2a1. The medium may be various storage media readable by the computer 2a, or it may be a communication line connected to the communication interface 2a3. The memory unit 2a2 may include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing device 1 via a communication line such as a LAN (Local Area Network).In this disclosure, circuits, units, and means are hardware programmed to perform or configured to perform the functions described. Such hardware may be any hardware described in this disclosure, or any hardware known to be programmed to perform or execute the functions described. If such hardware is a processor that is considered to be a type of circuit, such circuit, means, or unit is a combination of hardware and software used to constitute such hardware and / or processor.

[0012] [Plasma treatment device] The following describes an example configuration of an inductively coupled plasma processing apparatus as an example of a plasma processing apparatus 1. Figure 2 is an example diagram illustrating the configuration of an inductively coupled plasma processing apparatus.

[0013] The inductively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply system 30, and an exhaust system 40. The plasma processing chamber 10 includes a dielectric window 101. The plasma processing apparatus 1 also includes a substrate support unit 11, a gas introduction unit, and an antenna 14. The substrate support unit 11 is located inside the plasma processing chamber 10. The antenna 14 is located on or above the plasma processing chamber 10 (i.e., on or above the dielectric window 101). The plasma processing chamber 10 has a plasma processing space 10s defined by the dielectric window 101, the side walls 102 of the plasma processing chamber 10, and the substrate support unit 11. The plasma processing chamber 10 is grounded.

[0014] The substrate support portion 11 includes a main body portion 111 and a ring assembly 112. The main body portion 111 has a central region 111a for supporting the substrate W and an annular region 111b for supporting the ring assembly 112. A wafer is an example of the substrate W. The annular region 111b of the main body portion 111 surrounds the central region 111a of the main body portion 111 in a plan view. The substrate W is placed on the central region 111a of the main body portion 111, and the ring assembly 112 is placed on the annular region 111b of the main body portion 111 so as to surround the substrate W on the central region 111a of the main body portion 111. Therefore, the central region 111a is also called the substrate support surface for supporting the substrate W, and the annular region 111b is also called the ring support surface for supporting the ring assembly 112.

[0015] 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 bias electrode. The electrostatic chuck 1111 is placed on the base 1110. The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic chuck electrode 1111b placed within the ceramic member 1111a. The electrostatic chuck electrode 1111b is also called a clamping electrode. In one embodiment, the electrostatic chuck electrode 1111b is electrically connected or coupled to a chuck power supply. The chuck power supply may be a DC power supply or an AC power supply. The ceramic member 1111a has a central region 111a. In one embodiment, the ceramic member 1111a also has an annular region 111b. Furthermore, other members surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member, may have an annular region 111b. In this case, the ring assembly 112 may be placed on the annular electrostatic chuck or the annular insulating member, or on both the electrostatic chuck 1111 and the annular insulating member. In addition, at least one bias electrode, electrically connected or coupled to the power supply 31 and / or power supply 32 described later, may be placed within the ceramic member 1111a. Furthermore, the conductive member of the base 1110 and the bias electrode in the ceramic member 1111a may function as multiple bias electrodes. Also, the electrostatic chuck electrode 1111b may function as a bias electrode. Therefore, the substrate support portion 11 includes at least one bias electrode.

[0016] 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 covering ring. The edge rings are formed of a conductive or insulating material, and the covering rings are formed of an insulating material.

[0017] Further, the substrate support portion 11 may include a temperature control module configured to adjust at least one of the electrostatic chuck 1111, the ring assembly 112, and the substrate W to a target temperature. The temperature control module may include a heater, a heat transfer medium, a flow path 1110a, or a combination thereof. A heat transfer fluid such as brine or gas flows through the flow path 1110a. In one embodiment, the flow path 1110a is formed in the base 1110, and one or more heaters are disposed within the ceramic member 1111a of the electrostatic chuck 1111. Further, the substrate support portion 11 may include a heat transfer gas supply portion configured to supply a heat transfer gas to a gap between the back surface of the substrate W and the central region 111a.

[0018] The gas introduction portion is configured to introduce at least one processing gas from the gas supply portion 20 into the plasma processing space 10s. In one embodiment, the gas introduction portion includes a central gas injector (CGI) 13. The central gas injector 13 is disposed above the substrate support portion 11 and is attached to a central opening formed in the dielectric window 101. The central gas injector 13 has at least one gas supply port 13a, at least one gas flow path 13b, and at least one gas introduction port 13c. The processing gas supplied to the gas supply port 13a passes through the gas flow path 13b and is introduced into the plasma processing space 10s from the gas introduction port 13c. Note that the gas introduction portion may include one or more side gas injectors (SGIs) attached to one or more openings formed in the side wall 102 in addition to or instead of the central gas injector 13.

[0019] The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one processing gas from a corresponding gas source 21 to the gas introduction unit via a corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Further, 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.

[0020] The power supply system 30 includes a power supply 31 that is electrically connected or coupled to the plasma processing chamber 10. In one embodiment, the power supply 31 is electrically connected or coupled to the plasma processing chamber 10 via at least one impedance matcher. The impedance matcher may be a mechanically controlled matcher or an electronically controlled matcher. The power supply 31 is configured to supply at least one RF signal (RF power) to at least one bias electrode and the antenna 14. Thereby, plasma is generated from at least one processing gas supplied to the plasma processing space 10s. Therefore, the power supply 31 may function as at least a part of the plasma generation unit 12. Also, by supplying a bias RF signal to at least one bias electrode, a bias potential is generated on the substrate W, and ions in the formed plasma can be drawn into the substrate W.

[0021] The power supply 31 includes a first RF generation unit 31a and a second RF generation unit 31b. The first RF generation unit 31a is electrically connected to or coupled to the antenna 14 and is configured to generate a source RF signal (source RF power) to generate plasma in the plasma processing space 10s. In one embodiment, the first RF generation unit 31a is electrically connected to or coupled to the antenna 14 via at least one impedance matcher. In one embodiment, the source RF signal has a frequency in the range of 10 MHz to 150 MHz. In one embodiment, the first RF generation unit 31a may be configured to generate a plurality of source RF signals having different frequencies. One or more generated source RF signals are supplied to the antenna 14.

[0022] The second RF generation unit 31b is electrically connected to or coupled to at least one bias electrode and is configured to generate a first bias RF signal (first bias RF power). In one embodiment, the second RF generation unit 31b is electrically connected to or coupled to at least one bias electrode via at least one impedance matcher. The frequency of the first bias RF signal may be the same as or different from the frequency of the source RF signal. In one embodiment, the first bias RF signal has a frequency lower than the frequency of the source RF signal. In one embodiment, the first bias RF signal has a frequency in the range of 100 kHz to 60 MHz.

[0023] The third RF generation unit 31c is electrically connected to or coupled to at least one bias electrode and is configured to generate a second bias RF signal (second bias RF power). In one embodiment, the third RF generation unit 31c is electrically connected to or coupled to at least one bias electrode via at least one impedance matcher. The frequency of the second bias RF signal may be the same as or different from the frequency of the source RF signal. In one embodiment, the second bias RF signal has a lower frequency than the frequency of the source RF signal. Also, the second bias RF signal has a lower frequency than the frequency of the first bias RF signal. In one embodiment, the second bias RF signal has a frequency in the range of 100 kHz to 60 MHz.

[0024] In one embodiment, the second RF generation unit 31b and the third RF generation unit 31c may be configured to generate a plurality of bias RF signals having different frequencies. That is, the second RF generation unit 31b may be configured to generate a first bias RF signal and a second bias RF signal. The generated one or more bias RF signals (first bias RF signal, second bias RF signal) are supplied to at least one bias electrode. In various embodiments, at least one of the source RF signal and the bias RF signal (first bias RF signal, second bias RF signal) may be pulsed.

[0025] Here, the first RF generation unit 31a supplies a first RF signal (hereinafter also referred to as "HF power") as a source RF signal to the antenna 14. Preferably, the first RF signal has a frequency in the range of 20 MHz to 60 MHz. Specifically, the first RF signal will be described as having a frequency of 27 MHz, for example.

[0026] The second RF generation unit 31b supplies a second RF signal (hereinafter also referred to as "LF1 power") as the first bias RF signal to the bias electrode of the substrate support unit 11. The second RF signal has a frequency lower than the frequency of the first RF signal. Preferably, the second RF signal has a frequency in the range of 1 MHz to 15 MHz. Specifically, the second RF signal will be described as having a frequency of 13 MHz, for example.

[0027] The third RF generation unit 31c supplies a third RF signal (also referred to as "LF2 power" in the following description) as a second bias RF signal to the bias electrode of the substrate support unit 11. The third RF signal has a frequency lower than the frequency of the second RF signal. Preferably, the third RF signal has a frequency in the range of, for example, 100 kHz to 4 Hz (however, a frequency lower than the frequency of the second bias RF signal). Specifically, the third RF signal will be described as having a frequency of, for example, 1.2 MHz.

[0028] The power supply system 30 may also include a power supply 32 that is electrically connected to or coupled to the plasma processing chamber 10. The power supply 32 includes a voltage generation unit 32a. In one embodiment, the voltage generation unit 32a is electrically connected to or coupled to at least one bias electrode and configured to generate a voltage signal. The generated voltage signal is applied to at least one bias electrode.

[0029] In various embodiments, the voltage signal may be pulsed. In this case, the voltage generation unit 32a functions as a voltage pulse generation unit configured to generate a sequence of voltage pulses. Thus, the sequence of voltage pulses is applied to at least one bias electrode. In one embodiment, the sequence of voltage pulses has multiple cycles, each cycle including a burst of voltage pulses in a first period and a constant reference voltage in a second period. That is, the burst of voltage pulses is repeated in the sequence of voltage pulses. The absolute value of the voltage level of the voltage pulse is greater than the absolute value of the voltage level of the reference voltage. The voltage pulse may have an arbitrary waveform having a rectangular, trapezoidal, triangular, or a combination thereof, and the arbitrary waveform may change over time. The voltage pulse may have positive or negative polarity. Furthermore, the sequence of voltage pulses may include one or more positive voltage pulses and one or more negative voltage pulses within one cycle. Note that the voltage generation unit 32a may be provided in addition to the power supply 31, or it may be provided in place of the second RF generation unit 31b.

[0030] The antenna 14 includes one or more coils. In one embodiment, the antenna 14 may include an outer coil and an inner coil arranged coaxially. In this case, the power supply 31 may be connected to both the outer coil and the inner coil, or to either the outer coil or the inner coil. In the former case, the same RF generation unit may be connected to both the outer coil and the inner coil, or separate RF generation units may be connected to the outer coil and the inner coil separately.

[0031] The magnetic field generation unit 15 generates a magnetic field in the plasma processing space 10s. The magnetic field generation unit 15 is a ring-shaped magnet (permanent magnet, electromagnet, etc.) concentric with the substrate support unit 11. The magnetic field generation unit 15 is positioned on or above the plasma processing chamber 10 (i.e., on or above the dielectric window 101). Furthermore, the magnetic field generation unit 15 is positioned radially outward from the substrate support unit 11 than the antenna 14.

[0032] The magnetic field generated in the plasma processing space 10s by the magnetic field generation unit 15 induces cyclotron motion in electrons in the plasma. This confines the electrons within the plasma, increasing the electron density. Therefore, the stability of plasma maintenance is improved. In other words, the pressure range in which plasma can be stably generated is expanded.

[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 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.

[0034] [Plasma etching process] Next, an example of plasma etching will be explained using Figures 3 to 6. Figure 3 is a flowchart of an example of plasma etching. Figure 4 is a time chart showing an example of plasma etching. In Figure 4, the time charts for the power of the first RF signal, the power of the second RF signal, the power of the third RF signal, and the ion flux Γi drawn into the substrate W are shown. Also in Figure 4, IAD is a schematic diagram showing the ion angle distribution in each step S102 to S107. In IAD, the horizontal axis shows the ion angle, and the vertical axis shows the frequency. Figures 5 and 6 are examples of schematic cross-sectional diagrams of the substrate W.

[0035] First, the configuration of the substrate W before the plasma etching process is started will be explained using Figure 5(a). Figure 5(a) is an example of a schematic cross-sectional view of the substrate W before the plasma etching process shown in Figures 3 and 4 is started. The substrate W has a base film 500, a carbon-containing film (film to be etched) 510, and a mask 520.

[0036] The underlayer film 500 has a recess 500a. In the example shown in Figure 5, the underlayer film 500 includes, for example, a substrate 501, a first film 502 formed to cover the surface of the substrate 501, and a second film 503 formed to cover the surface of the second film 503. The side walls and bottom surface of the recess 500a are covered by the first film 502 and the second film 503. For example, the second film 503 has etching resistance to the plasma of the processing gas described later, compared to the carbon-containing film 510.

[0037] Although the base film 500 has been described as being covered with a first film 502 and a second film 503, it is not limited to this. The side walls and bottom surface of the recess 500a of the base film 500 may be covered with either the first film 502 or the second film 503. Furthermore, the side walls and bottom surface of the recess 500a of the base film 500 may not be covered with the first film 502 and the second film 503. Also, the side walls and bottom surface of the recess 500a of the base film 500 may be covered with multiple films.

[0038] The carbon-containing film 510 is, for example, an organic film. The carbon-containing film 510 is embedded in the recess 500a of the base film 500. The carbon-containing film 510 is also formed on the upper surface of the base film 500.

[0039] The mask 520 has an opening pattern and is formed on the carbon-containing film 510. For example, the mask 520 has etching resistance to the plasma of the processing gas described later, compared to the carbon-containing film 510.

[0040] As shown in Figure 5(a), a recess 500a of the base film 500 is located below the opening of the mask 520. The width of the recess 500a is narrower than the opening width of the mask 520. Also, as shown in Figure 5(a), the carbon-containing film 510 formed on the upper surface of the base film 500 may be etched through the opening of the mask 520.

[0041] Next, the structure of the substrate W after plasma etching will be explained using Figure 5(b). Figure 5(b) is an example of a schematic cross-sectional view of the substrate W after plasma etching shown in Figures 3 and 4. As shown in Figure 5(b), the carbon-containing film 510 is etched through a mask 520 having an opening pattern. The carbon-containing film 510 in the recesses 500a is also removed.

[0042] Here, if the opening width of the recess 500a is narrow (for example, about 1 nm to 2 nm), ions will have difficulty reaching the bottom of the recess 500a. In addition, the accumulation of deposits near the opening of the recess 500a will inhibit the etching of the carbon-containing film 510 inside the recess 500a. As a result, there is a risk that residue of the carbon-containing film 510 will remain at the corners between the side walls and the bottom surface inside the recess 500a.

[0043] Below, we will explain plasma etching, a process that improves the performance of removing residue, using Figures 3 to 6.

[0044] In step S101, the substrate W is prepared. First, the control unit 2 controls a transport device (not shown) to place the substrate W shown in Figure 5(a) onto the substrate support unit 11. The control unit 2 also controls the exhaust system 40 to adjust the pressure in the plasma processing space 10s to a predetermined pressure. It is preferable that the pressure in the plasma processing space 10s be 15 mTorr or less. In subsequent steps (S102 to S108), the pressure in the plasma processing space 10s is also adjusted to a predetermined pressure.

[0045] In step S102, a first etching process is performed. The first etching process is an etching process that generates a plasma of processing gas. Here, the control unit 2 controls the gas supply unit 20 to supply a predetermined processing gas (etching gas) from the central gas injection unit 13 to the plasma processing space 10s. As the processing gas (etching gas), for example, a mixed gas of H2 gas and N2 gas is supplied. The control unit 2 also controls the power supply system 30 to supply a first RF signal (HF power) at a first power level P1 from the first RF generation unit 31a to the antenna 14, and a second RF signal (LF1 power) at a third power level P3 from the second RF generation unit 31b to the bias electrode of the substrate support unit 11. The first power level P1 is preferably, for example, 2000W or higher.

[0046] As shown in Figure 4, supplying the first RF signal for plasma generation to the antenna 14 increases the ion flux Γi, which then becomes approximately constant.

[0047] Figure 6(a) is an example of a schematic cross-sectional view of the substrate W in step S102. By supplying a first RF signal (HF power) at a first power level P1 to the antenna 14, a plasma of the processing gas is generated in the plasma processing space 10s. Furthermore, by supplying a second RF signal (LF1 power) at a third power level P3 to the bias electrode of the substrate support 11, ions 601 of the processing gas generated by the plasma are drawn into the substrate W, etching the carbon-containing film 510 in the recess 500a. This etches the carbon-containing film 510 through the mask 520 having an opening pattern. The carbon-containing film 510 in the recess 500a is also removed.

[0048] In this process, reaction by-products 512 generated when the carbon-containing film 510 is etched accumulate near the opening of the recess 500a, forming deposits 530. This narrows the opening width of the recess 500a. Additionally, residues 511 of the carbon-containing film 510 remain at the corners between the side walls and the bottom surface within the recess 500a.

[0049] In step S103, the first afterglow etching process is performed. The first afterglow etching process is an etching process performed after the first etching process which generates plasma. Here, the control unit 2 controls the gas supply unit 20 to continue supplying a predetermined processing gas (etching gas) from the central gas injection unit 13 to the plasma processing space 10s, as in step S102. The control unit 2 also controls the power supply system 30 to supply a third RF signal (LF2 power) at the fifth power level P5 to the bias electrode of the substrate support unit 11 from the third RF generation unit 31c.

[0050] As shown in Figure 4, stopping the supply of the first RF signal for plasma generation reduces the ion flux Γi.

[0051] Figure 6(b) is an example of a schematic cross-sectional view of the substrate W in step S103. By supplying a third RF signal (LF2 power) at the fifth power level P5 to the bias electrode of the substrate support 11, ions 601 of the processing gas generated by the plasma in step S102 are drawn into the substrate W, etching the carbon-containing film 510 in the recess 500a. At this time, the distribution of IAD in step S103 is narrower than the distribution of IAD in step S102. Therefore, the ions 601 are incident approximately perpendicular to the substrate W and reach the bottom surface of the recess 500a. Thus, the residue 511 in the recess 500a is removed by etching.

[0052] In step S104, a sputtering process is performed. Here, the control unit 2 controls the gas supply unit 20 to continue supplying a predetermined processing gas (etching gas) from the central gas injection unit 13 to the plasma processing space 10s, as in step S102. The control unit 2 also controls the power supply system 30 to supply a second RF signal (LF1 power) at a fourth power level P4 to the bias electrode of the substrate support unit 11 from the second RF generation unit 31b. Here, the fourth power level P4 of the second RF signal is smaller than the third power level P3.

[0053] As shown in Figure 4, the ion flux Γi decreases further by continuously stopping the supply of the first RF signal for plasma generation.

[0054] Figure 6(c) is an example of a schematic cross-sectional view of the substrate W in step S104. By supplying a second RF signal (LF1 power) at the fourth power level P4 to the bias electrode of the substrate support 11, ions 601 of the processing gas generated by the plasma in step S102 are drawn into the substrate W. At this time, the distribution of IAD in step S104 is wider than the distribution of IAD in step S103. As a result, the deposits 530 accumulated near the opening of the recess 500a are removed by sputtering of ions 601, releasing reaction byproduct particles 531.

[0055] In step S105, the exhaust process is performed. Here, the control unit 2 controls the gas supply unit 20 and continues to supply a predetermined processing gas (etching gas) from the central gas injection unit 13 to the plasma processing space 10s, as in step S102.

[0056] Figure 6(d) is an example of a schematic cross-sectional view of the substrate W in step S105. Here, sputtered reaction byproduct particles 531, etc., are exhausted to the outside of the plasma processing chamber 10 along with the processing gas.

[0057] In step S106, a second etching process is performed. The second etching process is an etching process that generates a plasma of processing gas. Here, the control unit 2 controls the gas supply unit 20 and continues to supply a predetermined processing gas (etching gas) from the central gas injection unit 13 to the plasma processing space 10s, as in step S102. The control unit 2 also controls the power supply system 30 to supply a first RF signal (HF power) with a second power level P2 from the first RF generation unit 31a to the antenna 14, and a third RF signal (LF2 power) with a sixth power level P6 from the third RF generation unit 31c to the bias electrode of the substrate support unit 11. Here, the second power level P2 of the first RF signal is smaller than the first power level P1. The sixth power level P6 of the third RF signal may be equal to the fifth power level P5, smaller than the fifth power level P5, or larger than the fifth power level P5.

[0058] As shown in Figure 4, supplying the first RF signal for plasma generation to the antenna 14 increases the ion flux Γi, which then becomes approximately constant.

[0059] Figure 6(e) is an example of a schematic cross-sectional view of the substrate W in step S106. By supplying a first RF signal (HF power) at the second power level P2 to the antenna 14, a plasma of the processing gas is generated in the plasma processing space 10s. Furthermore, by supplying a third RF signal (LF2 power) at the sixth power level P6 to the bias electrode of the substrate support 11, ions 602 of the processing gas generated by the plasma are drawn into the substrate W, etching the carbon-containing film 510 in the recess 500a. At this time, the distribution of IAD in step S106 is narrower than the distribution of IAD in step S102. Therefore, the ions 602 are incident approximately perpendicular to the substrate W and reach the bottom surface of the recess 500a. Thus, the residue 511 in the recess 500a is further removed by etching.

[0060] Furthermore, by setting the first RF signal (HF power) supplied to the antenna 14 to a second power level P2 which is lower than the first power level P1, the accumulation of deposits 530 near the opening of the recess 500a is suppressed.

[0061] In step S107, a second afterglow etching process is performed. The second afterglow etching process is an etching process performed after the second etching process, which generates plasma. Here, the control unit 2 controls the gas supply unit 20 to continue supplying a predetermined processing gas (etching gas) from the central gas injection unit 13 to the plasma processing space 10s, as in step S102. The control unit 2 also controls the power supply system 30 to supply a third RF signal (LF2 power) at the sixth power level P6 to the bias electrode of the substrate support unit 11 from the third RF generation unit 31c.

[0062] As shown in Figure 4, stopping the supply of the first RF signal for plasma generation reduces the ion flux Γi.

[0063] Figure 6(f) is an example of a schematic cross-sectional view of the substrate W in step S107. By supplying the third RF signal (LF2 power) at the sixth power level P6 to the bias electrode of the substrate support 11, ions 602 of the processing gas generated by the plasma in step S102 are drawn into the substrate W, etching the carbon-containing film 510 in the recess 500a. At this time, the distribution of IAD in step S107 is narrower than the distribution of IAD in step S102. Therefore, the ions 602 are incident almost perpendicular to the substrate W and reach the bottom surface of the recess 500a. Thus, the residue 511 in the recess 500a is further removed by etching.

[0064] In step S108, the control unit 2 determines whether a predetermined number of repetitions of the process from step S102 to step S107 has elapsed. If the number of repetitions has not elapsed (S108 - NO), the control unit 2 returns to step S102 and repeats the cycle. If the number of repetitions has elapsed (S108 - YES), the etching process is terminated.

[0065] Subsequently, the control unit 2 controls the transport device (not shown) to remove the substrate W shown in Figure 5(b) from the substrate support unit 11.

[0066] As described above, the first etching step (S102) generates ion flux Γi and etches the carbon-containing film 510 in the recess 500a. The first afterglow etching step (S103) removes (etches) the residue 511 of the carbon-containing film formed at the corner between the side wall and the bottom surface of the recess 500a. The sputtering step (S104) removes the deposits 530 accumulated near the opening of the recess 500a by sputtering ions 601. The exhaust step (S105) exhausts the reaction byproduct particles 531. The second etching step (S106) generates ion flux Γi and removes (etches) the residue 511 of the carbon-containing film formed at the corner between the side wall and the bottom surface of the recess 500a. The second afterglow etching step (S107) removes (etches) the carbon-containing film residue 511 formed at the corner between the side wall and the bottom surface of the recess 500a.

[0067] The plasma etching process shown in Figures 3 to 6 can improve the removal performance of residue 511 within the recess 500a. In particular, even when the opening width of the recess 500a is narrow (for example, about 1 nm to 2 nm), it is possible to suppress the retention of carbon-containing film residue 511 in the corner portion between the side wall and the bottom surface within the recess 500a.

[0068] Furthermore, by setting the pressure in the plasma processing space 10s to 15 mTorr or less, it is possible to suppress the re-deposition of the reaction by-product particles 531 sputtered in step S104. In other words, the removal performance of the deposits 530 can be improved.

[0069] Furthermore, by setting the pressure in the plasma processing space 10s to 15 mTorr or less, the stability of plasma maintenance may decrease when generating plasma in steps S102 and S106. In contrast, by forming a magnetic field in the plasma processing space 10s using the magnetic field generation unit 15, cyclotron motion is generated in the electrons, and the electron density of the plasma can be increased. This improves the stability of plasma maintenance.

[0070] While embodiments of the plasma processing system have been described above, this disclosure is not limited to the embodiments described above, and various modifications and improvements are possible within the scope of the gist of this disclosure as described in the claims.

[0071] The embodiments disclosed above include, for example, the following aspects: (Note 1) A plasma processing chamber having a plasma processing space, Antenna and, The plasma processing chamber is arranged and has a bias electrode and a substrate support portion that supports the substrate, A gas introduction unit for supplying processing gas into the plasma processing space, A first RF generation unit that supplies a first RF signal to the antenna, A second RF generation unit that supplies a second RF signal to the bias electrode, A third RF generation unit that supplies a third RF signal to the bias electrode, An exhaust system for adjusting the pressure within the plasma processing space, It comprises a control unit and, The control unit, The process involves supplying the first RF signal of the first power level to the antenna and supplying the second RF signal of the third power level to the bias electrode, A step of supplying the third RF signal of the fifth power level to the bias electrode, A step of supplying the second RF signal of the fourth power level to the bias electrode, A step of exhausting the gas in the plasma processing space, The process involves supplying the first RF signal at the second power level to the antenna and supplying the third RF signal at the sixth power level to the bias electrode, The following steps are performed: supplying the third RF signal of the sixth power level to the bias electrode, and the system is configured to perform these steps. Plasma processing equipment. (Note 2) The second RF signal has a frequency lower than the frequency of the first RF signal. The third RF signal has a frequency lower than the frequency of the second RF signal. The plasma processing apparatus described in Appendix 1. (Note 3) The second power level is less than the first power level. A plasma processing apparatus as described in Appendix 1 or Appendix 2. (Note 4) The fourth power level is less than the third power level. A plasma processing apparatus as described in any of Appendix 1 to Appendix 3. (Note 5) The pressure in the plasma processing space is 15 Torr or less. A plasma processing apparatus as described in any of Appendix 1 to Appendix 4. (Note 6) The system further comprises a magnetic field generating unit that generates a magnetic field in the plasma processing space. A plasma processing apparatus as described in any of Appendix 1 to Appendix 5. (Note 7) A plasma etching method for a plasma processing apparatus comprising: a plasma processing chamber having a plasma processing space; an antenna; a substrate support portion disposed in the plasma processing chamber and having a bias electrode and supporting a substrate; a gas introduction portion for supplying a processing gas into the plasma processing space; a first RF generation unit for supplying a first RF signal to the antenna; a second RF generation unit for supplying a second RF signal to the bias electrode; a third RF generation unit for supplying a third RF signal to the bias electrode; and an exhaust system for adjusting the pressure in the plasma processing space, wherein The process of preparing the circuit board, The process involves supplying the first RF signal of the first power level to the antenna and supplying the second RF signal of the third power level to the bias electrode, A step of supplying the third RF signal of the fifth power level to the bias electrode, A step of supplying the second RF signal of the fourth power level to the bias electrode, A step of exhausting the gas in the plasma processing space, The process involves supplying the first RF signal at the second power level to the antenna and supplying the third RF signal at the sixth power level to the bias electrode, The process includes supplying the third RF signal of the sixth power level to the bias electrode, Plasma treatment method. (Note 8) The second RF signal has a frequency lower than the frequency of the first RF signal. The third RF signal has a frequency lower than the frequency of the second RF signal. The plasma treatment method described in Appendix 7. (Note 9) The second power level is less than the first power level. The plasma treatment method described in Appendix 7 or Appendix 8. (Note 10) The fourth power level is less than the third power level. A plasma treatment method as described in any of Appendix 7 to Appendix 9. (Note 11) The pressure in the plasma processing space is 15 Torr or less. A plasma treatment method as described in any of Appendix 7 to Appendix 10. (Note 12) The system further comprises a magnetic field generating unit that generates a magnetic field in the plasma processing space. A plasma treatment method as described in any of Appendix 7 to Appendix 11. (Note 13) The substrate has a recess and an etching target film embedded in the recess. A plasma treatment method as described in any of Appendix 7 to Appendix 12. [Explanation of Symbols]

[0072] 1. Plasma processing equipment 2 Control Unit 10 Plasma processing chamber 10s Plasma Processing Space 11. Substrate support section 12 Plasma generation section 13. Central gas injection section (gas inlet section) 14 Antennas 15 Magnetic field generation section 20 Gas Supply Department 30 Power Systems 31 Power supply 31a First RF generation unit 31b Second RF generation unit 31c Third RF generation unit 32 Power supply 32a Voltage generation unit 40 Exhaust System 500 Undercoat 500a recess 510 Carbon-containing film (film to be etched) 511 Residue 512 Reaction By-products 520 masks 530 Sediments 531 particles 601,602 Aeon W board P1 First Power Level P2 Second Power Level P3 3rd Power Level P4 4th Power Level P5 5th Power Level P6 6th Power Level

Claims

1. A plasma processing chamber having a plasma processing space, Antenna and, The plasma processing chamber is arranged and has a bias electrode and a substrate support portion that supports the substrate, A gas introduction unit for supplying processing gas into the plasma processing space, A first RF generation unit that supplies a first RF signal to the antenna, A second RF generation unit that supplies a second RF signal to the bias electrode, A third RF generation unit that supplies a third RF signal to the bias electrode, An exhaust system for adjusting the pressure within the plasma processing space, It comprises a control unit and, The control unit, The process involves supplying the first RF signal of the first power level to the antenna and supplying the second RF signal of the third power level to the bias electrode, A step of supplying the third RF signal of the fifth power level to the bias electrode, A step of supplying the second RF signal of the fourth power level to the bias electrode, A step of exhausting the gas in the plasma processing space, The process involves supplying the first RF signal at the second power level to the antenna and supplying the third RF signal at the sixth power level to the bias electrode, The system is configured to perform the steps of supplying the third RF signal of the sixth power level to the bias electrode, Plasma processing equipment.

2. The second RF signal has a frequency lower than the frequency of the first RF signal. The third RF signal has a frequency lower than the frequency of the second RF signal. The plasma processing apparatus according to claim 1.

3. The second power level is smaller than the first power level. The plasma processing apparatus according to claim 1.

4. The fourth power level is less than the third power level. The plasma processing apparatus according to claim 1.

5. The pressure in the plasma processing space is 15 Torr or less. The plasma processing apparatus according to claim 1.

6. The system further comprises a magnetic field generating unit that generates a magnetic field in the plasma processing space. The plasma processing apparatus according to claim 1.

7. A plasma etching method for a plasma processing apparatus comprising: a plasma processing chamber having a plasma processing space; an antenna; a substrate support portion disposed in the plasma processing chamber and having a bias electrode and supporting a substrate; a gas introduction portion for supplying a processing gas into the plasma processing space; a first RF generation unit for supplying a first RF signal to the antenna; a second RF generation unit for supplying a second RF signal to the bias electrode; a third RF generation unit for supplying a third RF signal to the bias electrode; and an exhaust system for adjusting the pressure in the plasma processing space, wherein The process of preparing the circuit board, The process involves supplying the first RF signal of the first power level to the antenna and supplying the second RF signal of the third power level to the bias electrode, A step of supplying the third RF signal of the fifth power level to the bias electrode, A step of supplying the second RF signal of the fourth power level to the bias electrode, A step of exhausting the gas in the plasma processing space, The process involves supplying the first RF signal at the second power level to the antenna and supplying the third RF signal at the sixth power level to the bias electrode, The process includes supplying the third RF signal of the sixth power level to the bias electrode, Plasma treatment method.

8. The second RF signal has a frequency lower than the frequency of the first RF signal. The third RF signal has a frequency lower than the frequency of the second RF signal. The plasma treatment method according to claim 7.

9. The second power level is smaller than the first power level. The plasma treatment method according to claim 7.

10. The fourth power level is less than the third power level. The plasma treatment method according to claim 7.

11. The pressure in the plasma processing space is 15 Torr or less. The plasma treatment method according to claim 7.

12. The system further comprises a magnetic field generating unit that generates a magnetic field in the plasma processing space. The plasma treatment method according to claim 7.

13. The substrate has a recess and an etching target film embedded in the recess. The plasma treatment method according to claim 7.

Images