Substrate processing device and substrate processing method

Abstract

A substrate processing apparatus and a substrate processing method for stably generating plasma under low pressure are provided. The apparatus comprises a process of generating plasma within the plasma processing chamber by supplying the source RF signal to the upper electrode while the electromagnet generates a magnetic field within the plasma processing chamber and depositing a deposit on the substrate, and repeating the process of generating plasma within the plasma processing chamber by supplying the source RF signal to the upper electrode while the electromagnet generates a magnetic field within the plasma processing chamber and etching the substrate, wherein the power level of the source RF signal in the process of etching the substrate is lower than the power level of the source RF signal in the process of depositing the deposit on the substrate.

Description

Technology Field

[0001] The present disclosure relates to a substrate processing apparatus and a substrate processing method. Background Technology

[0002] Patent Document 1 discloses a substrate processing method in a substrate processing apparatus, comprising: a) a process gas comprising fluorocarbon and noble gas to a processing vessel having a support stand for placing a workpiece comprising a first region composed of silicon oxide; b) a process of plasma treating the workpiece by means of a first plasma of the process gas generated under a first plasma generation condition; c) a process of plasma treating the workpiece having a bias potential generated on the workpiece by means of a second plasma of the process gas generated under a second plasma generation condition different from the first plasma generation condition; and d) a process of repeating b) and c). Prior art literature

[0003] Japanese Patent Publication No. JP 2021-150418 The problem to be solved

[0004] In one aspect, the present disclosure provides a substrate processing apparatus and a substrate processing method for stably generating plasma under low pressure. means of solving the problem

[0005] To solve the above problem, according to one embodiment, a plasma processing chamber adjusted to a pressure within the range of 1 mTorr to 20 mTorr; a substrate support member disposed within the plasma processing chamber and including a lower electrode and supporting a substrate; an upper electrode disposed above the substrate support member; an electromagnet having at least two ring-shaped coils arranged concentrically; a first RF power supply that supplies a source RF signal having a first RF frequency to the upper electrode; a second RF power supply that supplies a bias RF signal having a second RF frequency to the lower electrode; and a control unit, wherein the control unit comprises a process of generating plasma within the plasma processing chamber by supplying the source RF signal to the upper electrode while the electromagnet generates a magnetic field within the plasma processing chamber and depositing a deposit on the substrate, and generating plasma within the plasma processing chamber by supplying the source RF signal to the upper electrode while the electromagnet generates a magnetic field within the plasma processing chamber, and the substrate A substrate processing apparatus can be provided that repeats an etching process, wherein the power level of the source RF signal in the process of etching the substrate is lower than the power level of the source RF signal in the process of depositing the deposit on the substrate. Effects of the invention

[0006] According to one aspect, a substrate processing apparatus and a substrate processing method that stably generate plasma under low pressure can be provided. Brief explanation of the drawing

[0007] Figure 1 is an example of a drawing for explaining a configuration example of a capacitance-coupled plasma processing device. Figure 2 is an example of a schematic diagram showing the state of plasma when the generation of a magnetic field by the magnetic field generating unit is stopped. Figure 3 is an example of a schematic diagram showing the state of plasma in a state where a magnetic field is generated by a magnetic field generating unit. Figure 4 is an example of a time chart of an etching process. Figure 5a is an example of a cross-sectional schematic diagram of a structure formed on a substrate. Figure 5b is an example of a cross-sectional schematic diagram of a structure formed on a substrate. Figure 6a is a diagram showing an example of the range in which the plasma is stabilized. Figure 6b is a diagram showing an example of the range in which the plasma is stabilized. Figure 6c is a diagram showing an example of the range in which the plasma is stabilized. Figure 6d is a diagram showing an example of the range in which the plasma is stabilized. Figure 7 is an example of a graph showing the magnetic field of the substrate surface under each condition of the coil. FIG. 8 is a diagram illustrating an example of the effect of applying a magnetic field by a magnetic field generating unit. FIG. 9a is a diagram showing a configuration in which an electromagnet has two coils and an example of a magnetic field generated by the electromagnet. FIG. 9b is a diagram showing a configuration in which an electromagnet has two coils and an example of a magnetic field generated by the electromagnet. FIG. 10a is a diagram showing a configuration in which an electromagnet has four coils and an example of a magnetic field generated by the electromagnet. FIG. 10b is a diagram showing a configuration in which an electromagnet has four coils and an example of a magnetic field generated by the electromagnet. Specific details for implementing the invention

[0008] Hereinafter, various exemplary embodiments will be described in detail with reference to the drawings. For reference, identical or substantial parts in each drawing are given the same reference numerals.

[0009] [Plasma Processing System]

[0010] Below, an example of the configuration of a plasma processing system is described. FIG. 1 is an example of a drawing for explaining an example of the configuration of a capacitively coupled plasma processing device (substrate processing device) (1).

[0011] A plasma processing system includes a capacitively coupled plasma processing device (1) and a control unit (2). The capacitively coupled plasma processing device (1) includes a plasma processing chamber (10), a gas supply unit (20), a power supply (30), and an exhaust system (40). Additionally, the plasma processing device (1) includes a substrate support (11) and a gas introduction unit. The gas introduction unit is configured to introduce at least one processing gas into the plasma processing chamber (10). The gas introduction unit includes a shower head (13). The substrate support (11) is positioned within the plasma processing chamber (10). The shower head (13) is positioned above the substrate support (11). In one embodiment, the shower head (13) constitutes at least a portion of the ceiling (or ceiling) of the plasma processing chamber (10). The plasma processing chamber (10) has a plasma processing space (10s) defined by a shower head (13), a side wall (10a) of the plasma processing chamber (10), and a substrate support (11). The plasma processing chamber (10) has at least one gas supply port for supplying at least one processing gas to the plasma processing space (10s) and at least one gas discharge port for discharging gas from the plasma processing space (10s). The plasma processing chamber (10) is grounded. The shower head (13) and the substrate support (11) are electrically insulated from the case of the plasma processing chamber (10).

[0012] The substrate support portion (11) includes a main body portion (111) and a ring assembly (112). The main body portion (111) has a central region (111a) for supporting a substrate (W) and an annular region (111b) for supporting a ring assembly (112). A wafer is an example of a 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 planar 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) to surround the substrate (W) on the central region (111a) of the main body portion (111). Therefore, the central region (111a) is also called a substrate support surface for supporting the substrate (W), and the ring-shaped region (111b) is also called a ring support surface for supporting the ring assembly (112).

[0013] 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) and an electrostatic electrode (1111b) disposed within the ceramic member (1111a). The ceramic member (1111a) has a central region (111a). In one embodiment, the ceramic member (1111a) also has an annular region (111b). For reference, another member surrounding the electrostatic chuck (1111), such as an annular electrostatic chuck or an annular insulating member, may have the annular region (111b). In this case, the ring assembly (112) may be placed on an annular electrostatic chuck or an annular insulating member, or on both the electrostatic chuck (1111) and the annular insulating member. Additionally, at least one RF / DC electrode coupled to the RF (Radio Frequency) power source (31) and / or DC (Direct Current) power source (32) described later may be placed within the ceramic member (1111a). In this case, at least one RF / DC electrode functions as a lower electrode. When a bias RF signal and / or DC signal described later is supplied to at least one RF / DC electrode, the RF / DC electrode is also called a bias electrode. For reference, the conductive member of the support (1110) and at least one RF / DC electrode may function as a plurality of lower electrodes. Additionally, an electrostatic electrode (1111b) may function as a lower electrode. Therefore, the substrate support (11) includes at least one lower electrode.

[0014] 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 material or an insulating material, and the cover ring is formed of an insulating material.

[0015] Additionally, the substrate support (11) may include a temperature control module configured to control at least one of the electrostatic chuck (1111), ring assembly (112), and substrate (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 within the support (1110), and one or more heaters are disposed within the ceramic member (1111a) of the electrostatic chuck (1111). Additionally, the substrate support (11) may include a heat transfer gas supply unit configured to supply a heat transfer gas to the gap between the back surface of the substrate (W) and the central region (111a).

[0016] The shower head (13) is configured to introduce at least one processing gas from the gas supply unit (20) into the plasma processing space (10s). The shower head (13) has at least one gas supply port (13a), at least one gas diffusion chamber (13b), and a plurality of gas inlet ports (13c). The processing gas supplied through the gas supply port (13a) passes through the gas diffusion chamber (13b) and is introduced into the plasma processing space (10s) from the plurality of gas inlet ports (13c). Additionally, the shower head (13) includes at least one upper electrode. For reference, the gas inlet port may include, in addition to the shower head (13), one or more side gas injectors (SGI) installed in one or more openings formed in the side wall (10a).

[0017] The gas supply unit (20) may include at least one gas source (21) and at least one flow controller (22). In one embodiment, the gas supply unit (20) is configured to supply at least one processing gas from each corresponding gas source (21) to the shower head (13) through each corresponding flow controller (22). Each flow controller (22) may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, the gas supply unit (20) may include one or more flow modulation devices that modulate or pulse the flow of at least one processing gas.

[0018] The power supply (30) includes an RF power supply (31) coupled to the plasma processing chamber (10) through 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. Accordingly, plasma is formed from at least one processing gas supplied to the plasma processing space (10s). Therefore, the RF power supply (31) can function as at least part of a plasma generation unit configured to generate plasma from one or more processing gases in the plasma processing chamber (10). Additionally, by supplying a bias RF signal to at least one lower electrode, a bias potential is generated in the substrate (W), which can attract ionic components in the formed plasma to the substrate (W).

[0019] 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) (first RF power supply) is coupled to at least one lower electrode and / or at least one upper electrode through 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 first RF frequency (e.g., 60 MHz) within the range of 10 MHz to 150 MHz. In one embodiment, the first RF generating 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 at least one lower electrode and / or at least one upper electrode.

[0020] The second RF generating unit (31b) (second RF power supply) is coupled to at least one lower electrode through 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 second RF frequency (e.g., 12.88 MHz) within the range of 100 kHz to 60 MHz. In one embodiment, the second RF generating unit (31b) may be configured to generate a plurality of bias RF signals having different frequencies. One or more generated bias RF signals are supplied to at least one lower electrode. Additionally, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0021] Additionally, the power supply (30) may include a DC power supply (32) coupled to the plasma processing chamber (10). The DC power supply (32) includes a first DC generating unit (32a) and a second DC generating unit (32b). In one embodiment, the first DC generating unit (32a) is connected to at least one lower electrode and configured to generate a first DC signal. The generated first bias DC signal is applied to at least one lower electrode. In one embodiment, the second DC generating unit (32b) is connected to at least one upper electrode and configured to generate a second DC signal. The generated second DC signal is applied to at least one upper electrode.

[0022] In various embodiments, at least one of the first and second DC signals may be pulsed. In this case, a sequence of voltage pulses is applied to at least one lower electrode and / or at least one upper electrode. The voltage pulse may have a pulse waveform that is rectangular, trapezoidal, triangular, or a combination thereof. In one embodiment, a waveform generator for generating a sequence of voltage pulses from a DC signal is connected between the first DC generator (32a) and at least one lower electrode. Thus, the first DC generator (32a) and the waveform generator constitute a voltage pulse generator. When the second DC generator (32b) and the waveform generator constitute a voltage pulse generator, the voltage pulse generator is connected to at least one upper electrode. The voltage pulse may have positive polarity or negative polarity. Additionally, the sequence of voltage pulses may include one or more positive voltage pulses and one or more negative voltage pulses within one cycle. For reference, the first and second DC generating units (32a, 32b) may be installed in addition to the RF power supply (31), and the first DC generating unit (32a) may be installed in place of the second RF generating unit (31b).

[0023] The exhaust system (40) may be connected to a gas outlet (10e) installed at the bottom (or floor) of the plasma processing chamber (10), for example. The exhaust system (40) may include a pressure regulating valve and a vacuum pump. The pressure within the plasma processing space (10s) is regulated by the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0024] Additionally, the plasma processing device (1) has a magnetic field generating unit (50) that generates a magnetic field in the plasma processing space (10s). The magnetic field generating unit (50) has an electromagnet (51) and a power source (52).

[0025] The electromagnet (51) has a plurality of coils (511, 512) (two in the example of FIG. 1). The coils (511, 512) are ring-shaped coils arranged concentrically. The coil (512) is positioned radially outward from the coil (511). The coils (511, 512) are positioned outside the plasma processing space (10s) (outside the plasma processing chamber (10)). Additionally, the coils (511, 512) are positioned above the upper electrode (shower head (13)). Additionally, the coils (511, 512) are positioned concentrically with the central axis of the substrate support (11).

[0026] The power source (52) supplies power to the electromagnet (51). The power source (52) has a power source (521) that supplies power to the coil (511) and a power source (522) that supplies power to the coil (512). Here, the power source (521) supplies power so that current flows in one direction to the coil (511). In addition, the power source (522) supplies power so that current flows in the opposite direction to the one direction to the coil (512). Accordingly, the magnetic field generated by the coil (511) and the magnetic field generated by the coil (512) on the substrate (W) are canceled out, thereby reducing the magnetic field on the substrate (W).

[0027] For reference, the number of ring-shaped coils included in the electromagnet (51) is not limited to two, but may be more. The electromagnet (51) may have an even number of coils, and the coils adjacent in the diameter direction may have current flowing in opposite directions. Additionally, the electromagnet (51) may have multiple pairs of coils in which current flows in opposite directions. Furthermore, in the electromagnet (51) having multiple coils, the number of coils in which current flows in one direction and the number of coils in which current flows in the opposite direction may be the same. Additionally, the electromagnet (51) may have an odd number of coils, and the coils adjacent in the diameter direction may have current flowing in opposite directions. Additionally, although the description assumes that the multiple coils are arranged at the same height, they are not limited thereto, and the coils may be arranged at different positions in the height direction.

[0028] The control unit (2) processes computer-executable commands to execute various processes described in the present disclosure in the plasma processing device (1). The control unit (2) may be configured to control each element of the plasma processing device (1) to execute the various processes described herein. In one embodiment, part or all of the control unit (2) may be included in the plasma processing device (1). The control unit (2) may include a processing unit (2a1), a memory unit (2a2), and a communication interface (2a3). The control unit (2) is realized, for example, by a computer (2a). The processing unit (2a1) may be configured to perform various control operations by reading a program from the memory unit (2a2) and executing the read program. This program may be stored in the memory unit (2a2) in advance, or may be acquired via a medium when necessary. The acquired program is stored in the memory unit (2a2) and is read from the memory unit (2a2) and executed by the processing unit (2a1). The medium may be various storage media readable by a computer (2a) or a communication line connected to a communication interface (2a3). The processing unit (2a1) may be a CPU (Central Processing Unit). The storage unit (2a2) may include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or a combination thereof. The communication interface (2a3) may communicate with the plasma processing device (1) through a communication line such as a LAN (Local Area Network).

[0029] Next, a method for controlling the plasma generated in the plasma processing space (10s) by the magnetic field generating unit (50) will be explained using FIG. 2 and FIG. 3.

[0030] FIG. 2 is an example of a schematic diagram showing the state of plasma (P1) when the generation of a magnetic field by the magnetic field generating unit (50) is stopped.

[0031] Here, by supplying a source RF signal (source RF power) to the upper electrode (shower head (13)), plasma (P1) is generated between the upper electrode (shower head (13)) and the lower electrode (substrate support (11)). The electron density in the plasma (P1) is the electron density at the center side (E Center ) is the electron density (E) on the outer side Edge It becomes higher than )(E Center >E Edge In Figure 2, the intensity of electron density is schematically represented as the intensity of dot hatching.

[0032] In addition, when an etching treatment is performed on the substrate (W), the trend (251) of the etching rate is schematically shown. The trend (251) of the etching rate is correlated with the electron density in the plasma (P1), and shows a tendency for the etching rate to be high at the center side of the substrate (W) and for the etching rate to be low at the outer side of the substrate (W).

[0033] Additionally, when a charged particle (210) (e.g., electron, etc.) in the plasma (P1) moves toward the lower electrode by a bias RF signal (bias RF power) supplied to the lower electrode and reaches the sheath, the charged particle (210) is extinguished (shown as a dashed line in FIG. 2).

[0034] FIG. 3 is an example of a schematic diagram showing the state of plasma (P2) in a state where a magnetic field is generated by a magnetic field generating unit (50).

[0035] Here, by supplying a source RF signal (source RF power) to the upper electrode (shower head (13)), plasma (P2) is generated between the upper electrode (shower head (13)) and the lower electrode (substrate support (11)).

[0036] Here, an example of the magnetic flux (220) generated by the electromagnet (51) is indicated by a solid arrow. As shown in FIG. 3, the magnetic flux (220) has a direction toward the outer edge. Charged particles (210) in the plasma (P2) move toward the outer edge due to the Lorentz force of the magnetic flux (220) having a horizontal component. Accordingly, the electron density in the plasma (P2) is the electron density (E) on the outer edge. Edge ) is the electron density (E) on the center side Center It becomes higher than )(E Center <E Edge In Figure 3, the gradation of electron density is schematically represented as the gradation of dot hatching.

[0037] In addition, when performing an etching treatment on the substrate (W), the trend of the etching rate (252) is schematically shown. The trend of the etching rate (252) is correlated with the electron density in the plasma (P2), and shows a tendency for the etching rate to be high on the outer side of the substrate (W) and for the etching rate to be low on the center side of the substrate (W).

[0038] Additionally, when a charged particle (210) (e.g., electron) in the plasma (P2) moves in the direction of the lower electrode by a bias RF signal (bias RF power) supplied to the lower electrode and reaches the sheath, the charged particle (210) is extinguished (shown as a dashed line in FIG. 3). Here, when comparing FIG. 2 and FIG. 3, the distance traveled by the charged particle (210) until it reaches the sheath is longer in FIG. 3. In other words, the extinguishing of the charged particle (210) can be delayed.

[0039] Here, as the semiconductor device formed on the substrate (W) becomes smaller, there is a need to improve the uniformity of the plasma. In addition, in the plasma etching process, the plasma generated in the plasma processing chamber (10) controlled at a low pressure (1 mTorr to 20 mTorr) has high uniformity, and as a result, the uniformity of the etching rate is improved.

[0040] On the other hand, under low pressure, the density of gas molecules decreases, and collisions between gas molecules decrease, making it difficult to maintain the plasma. In addition, as the semiconductor device formed on the substrate (W) becomes smaller, there is a limit to increasing the intensity of the source RF signal (source RF power) that generates the plasma.

[0041] As shown in FIG. 3, by applying a magnetic field from a magnetic field generating unit (50), charged particles (210) in the plasma (P2) move along the magnetic flux (220). Accordingly, the distance traveled by the charged particles (210) until they reach the sheath is increased. In other words, the probability of collision with other gas molecules, etc., during the time it takes for the charged particles (210) to reach the sheath increases, and the density of the plasma increases. Accordingly, the plasma (P2) shown in FIG. 3 can suppress the deactivation of the plasma even under low pressure compared to the plasma (P1) shown in FIG. 2.

[0042] Next, an example of an etching process will be explained using FIG. 4 and FIG. 5a to FIG. 5b. FIG. 4 is an example of a time chart for an etching process. FIG. 5a to FIG. 5b is an example of a cross-sectional schematic diagram of a structure formed on a substrate (W). In FIG. 4, the top represents the power of the source RF signal (source RF power) (hereinafter also referred to as HF power), and the bottom represents the power of the bias RF signal (bias RF power) (hereinafter also referred to as LF power).

[0043] First, the control unit (2) controls a conveying device (not shown) to convey the substrate (W) to the substrate support (11) and supports the substrate (W) on the substrate support (11). Next, the control unit (2) controls the exhaust system (40) to control the pressure inside the plasma processing chamber (10) to a predetermined pressure. Here, the predetermined pressure is within the range of 1 mTorr to 20 mTorr. In addition, it is preferable that the predetermined pressure is within the range of 1 mTorr to 10 mTorr, and more preferable that it is within the range of 3 mTorr to 8 mTorr. Next, the control unit (2) controls the gas supply unit (20) to supply a processing gas. The processing gas includes, for example, C4F6, Ar, and O2. Additionally, the control unit (2) controls the power supply (52) to supply power from the power supply (52) to the electromagnet (51) (coil (511, 512)) and generates a magnetic field in the electromagnet (51).

[0044] Next, the control unit (2) controls the power supply (30) to supply a source RF signal (source RF power) to the upper electrode, supplies a bias RF signal (bias RF power) to the lower electrode, and performs an etching process on the substrate (W).

[0045] Here, the etching process repeats the process of depositing a deposit on the substrate (W) (S1, S2) and the process of etching the substrate (W) (S3, S4).

[0046] As shown in FIG. 4, the HF power of the deposition process (S1, S2) is greater than the HF power of the etching process (S3, S4). In addition, the LF power of the deposition process (S1, S2) is smaller than the LF power of the etching process (S3, S4). Accordingly, the amount of deposition of the deposit on the surface of the substrate (W) becomes dominant over the amount of etching.

[0047] As shown in FIG. 5a, an etching target film (510) (e.g., SiO2) and a mask (520) (e.g., SiN) are laminated on a substrate (W), and concave portions such as trenches and holes are formed in the etching target film (510) from the mask (520). In the process (S1, S2) of depositing the deposited material, a deposited material (530) is deposited on the surface of the substrate (W).

[0048] In addition, as shown in FIG. 4, the HF power of the etching process (S3, S4) is smaller than the HF power of the deposition process (S1, S2). Also, the LF power of the etching process (S3, S4) is larger than the LF power of the deposition process (S1, S2). Accordingly, the amount of etching on the surface of the substrate (W) becomes dominant over the amount of deposition of the deposition material (530).

[0049] As shown in FIG. 5b, in the etching process (S3, S4), the bottom of the concave portion of the etching target film (510) is etched.

[0050] Each step S1 to S4 is further explained using FIG. 4. The process of depositing the deposited material (S1, S2) has a first period (S1) and a second period (S2). The process of etching (S3, S4) has a third period (S3) and a fourth period (S4).

[0051] In step S1, during the first period, HF power of a first power level is supplied to the upper electrode, and LF power of a fifth power level is supplied to the lower electrode. Here, the first power level is within the range of 50 to 200 W. The fifth power level is within the range of 0 to 50 W. Here, by increasing the HF power, the deposition amount of the deposit (530) on the surface of the substrate (W) becomes dominant over the etching amount. Accordingly, CF on the upper surface of the mask (520) or on the side wall of the concave portion formed on the mask (520) and the etching target film (510). x A deposit (530) containing is deposited.

[0052] In step S2, during the second period, HF power of a second power level is supplied to the upper electrode, and LF power of a sixth power level is supplied to the lower electrode. Here, the second power level is within the range of 50 to 200 W. Also, the second power level is the same as the first power level. The sixth power level is higher than the fifth power level. Here, by increasing the HF power, the deposition amount of the deposit (530) on the surface of the substrate (W) becomes dominant over the etching amount. Also, by increasing the LF power, ions are drawn into the concave area, and the deposit (530) is etched at the bottom of the concave area.

[0053] In step S3, during the third period, HF power of a third power level is supplied to the upper electrode, and LF power of a seventh power level is supplied to the lower electrode. Here, the third power level is within the range of 50 to 200 W. Also, the third power level is lower than the first power level and the second power level. The seventh power level is higher than the sixth power level. Here, by reducing the HF power, the amount of etching on the surface of the substrate (W) becomes dominant over the amount of deposition of the deposit (530). Additionally, by further increasing the LF power, ions are attracted to the concave area, and the bottom of the concave area of ​​the etching target film (510) is etched.

[0054] In step S4, during the fourth period, HF power of a fourth power level is supplied to the upper electrode, and LF power of an eighth power level is supplied to the lower electrode. Here, the fourth power level is within the range of 50 to 200 W. Also, the fourth power level is lower than the first power level and the second power level, and is equal to the third power level. The eighth power level is higher than the seventh power level. Here, by reducing the HF power, the amount of etching on the surface of the substrate (W) becomes dominant over the amount of deposition of the deposit (530). Additionally, by further increasing the LF power, ions are attracted to the concave area, and the bottom of the concave area of ​​the etching target film (510) is etched.

[0055] In this way, the processing of steps S1 to S4 is one cycle, and by repeating this cycle, the bottom of the concave portion of the etching target film (510) is etched while protecting the mask (520) or the side wall of the concave portion with the deposit (530).

[0056] In addition, even if the HF power is reduced in the etching process (S3, S4), the deactivation of the plasma can be suppressed even under low pressure by applying a magnetic field by the magnetic field generating unit (50). In addition, the plasma generated in the plasma processing chamber (10) controlled at low pressure has high uniformity, and as a result, the uniformity of the etching rate is improved.

[0057] Next, an example of plasma being stably generated by applying a magnetic field by the magnetic field generating unit (50) will be explained using FIGS. 6a to 6d. FIGS. 6a to 6d are drawings showing an example of a range in which the plasma is stabilized. FIG. 6a shows a case where the coils (511, 512) do not generate a magnetic field. FIG. 6b shows a case where the coil (511) generates a magnetic field of -18[G] and the coil (512) generates a magnetic field of +18[G]. FIG. 6c shows a case where the coil (511) generates a magnetic field of -18[G] and the coil (512) generates a magnetic field of +36[G]. FIG. 6d shows a case where the coil (511) generates a magnetic field of -36[G] and the coil (512) generates a magnetic field of +36[G]. In addition, the table on the left shows the case where the pressure inside the plasma processing chamber (10) is 3 mTorr, and the table on the right shows the case where the pressure inside the plasma processing chamber (10) is 8 mTorr. X is the 8th power level, and Y is the 7th power level.

[0058] Here, the first and second power levels were set to 100[W], the third and fourth power levels to 50[W], the fifth power level to 0[W], the sixth power level to 40[W], the seventh power level to Y[W], and the eighth power level to X[W], and the experiment was conducted to verify whether the plasma was generated stably.

[0059] '○' is assigned when the plasma was generated stably, and '-' or '×' is assigned when the plasma was not generated stably. Additionally, stable plasma generation is indicated by shading.

[0060] At 8 mTorr, as shown in Figures 6a to 6d, plasma is stably generated in many X and Y combination regions.

[0061] Meanwhile, as shown in Fig. 6a, when no magnetic field is generated at 3 mTorr, plasma was not stably generated in many X,Y combination regions.

[0062] In this regard, as shown in Figures 6b to 6d when a magnetic field is generated at 3 mTorr, the X and Y combination region where the plasma is stably generated increases compared to Figure 6a.

[0063] In this way, by applying a magnetic field generated by the magnetic field generating unit (50) into the plasma processing chamber (10), the range in which plasma can be stably generated even under low pressure (e.g., 3 mTorr) is expanded.

[0064] Next, the relationship between the magnetic field generated by the coils (511, 512) and the magnetic field on the surface of the substrate (W) is explained using FIG. 7. FIG. 7 is an example of a graph showing the magnetic field on the surface of the substrate (W) under each condition of the coils (511, 512). Here, Zone 1 represents the magnetic field generated by the coil (511). Zone 2 represents the magnetic field generated by the coil (512). The magnetic field generated by the coil (511) is -18[G], 0[G], and +18[G], and the magnetic field generated by the coil (512) is -18[G], 0[G], +18[G], and +36[G]. For combinations thereof, the simulation results of the radial position (Wafer Location) from the center of the substrate (W) and the magnetic field (B) at that position are shown. For reference, the radius of the substrate (W) is set to 150[mm].

[0065] As shown in FIG. 7, the combination of (Zone 1, Zone 2) at (-18[G], +18[G]) and (+18[G], -18[G]) indicates that the influence of the magnetic field in the region of the substrate (W) is small. That is, when the direction of the current flowing through the coil (511) and the direction of the current flowing through the coil (512) are opposite, the influence of the magnetic field in the region of the substrate (W) is small. Accordingly, the influence of the magnetic field on the etching characteristics (etching rate, uniformity) of the substrate (W) can be suppressed.

[0066] For reference, FIG. 7 describes an example in which the current flowing through the coils (511, 512) is controlled to reduce the influence of the magnetic field in the region of the substrate (W), but it is not limited thereto. The current flowing through the coils (511, 512) may also be controlled to adjust the density of the plasma.

[0067] FIG. 8 is a diagram illustrating an example of the effect of applying a magnetic field by a magnetic field generating unit (50). Here, the combination of (Zone 1, Zone 2) is described as an example of (0[G], 0[G]), (-18[G], +18[G]), and (-18[G], +36[G]).

[0068] At (0[G], 0[G]), the magnetic field on the substrate support (11) is 0. Therefore, the charged particles in the plasma treatment chamber (10) increase in the diameter direction near the center.

[0069] At (-18[G], +18[G]), the magnetic field on the substrate (W) is approximately 0, and the magnetic field increases from the outside of the substrate (W). Therefore, the charged particles in the plasma treatment chamber (10) increase in the radial direction near the outer periphery.

[0070] At (-18[G], +36[G]), the magnetic field increases from the outer edge of the substrate (W) to the vicinity of the ring assembly (112) (edge ​​ring). Consequently, the number of charged particles in the plasma processing chamber (10) increases in the radial direction near the outer periphery.

[0071] In this way, by controlling the magnetic field generated by the coils (511, 512), the density of the plasma in the diameter direction can be adjusted.

[0072] FIGS. 9a and 9b are drawings showing a configuration in which an electromagnet (51a) is equipped with two coils (511 to 512) and an example of a magnetic field generated by the electromagnet (51a). FIG. 9a is an example of a partial enlarged view of a substrate processing device showing an example of the arrangement of the coils (511 to 512). FIG. 9b shows a radial location from the center of the substrate (W) and the simulation results of the magnetic field (B) at that location. For reference, the radius of the substrate (W) is set to 150 mm. For reference, in FIGS. 9a and 9b, the location where the magnetic field (B) becomes a peak is indicated by a dashed line.

[0073] FIGS. 10a and 10b are drawings showing a configuration in which an electromagnet (51b) is equipped with four coils (511 to 514) and an example of a magnetic field generated by the electromagnet (51b). FIG. 10a is an example of a partial enlarged view of a substrate processing device showing an example of the arrangement of the coils (511 to 514). FIG. 10b shows a radial location from the center of the substrate (W) and the simulation results of the magnetic field (B) at that location. For reference, the radius of the substrate (W) is set to 150 mm. For reference, in FIGS. 10a and 10b, the location where the magnetic field (B) becomes a peak is indicated by a dashed line.

[0074] As shown in comparison with FIG. 9a and FIG. 10a, in a configuration having four coils (511 to 514), the coils are arranged outward in the radial direction compared to a configuration having two coils (511 to 512). Accordingly, as shown in comparison with FIG. 9b and FIG. 10b, in a configuration having four coils (511 to 514), the plasma density near the side wall (10a) can be increased compared to a configuration having two coils (511 to 512).

[0075] In this way, by changing the number or position of the electromagnet coils, the location where the plasma density increases can be adjusted.

[0076] The embodiments disclosed above include, for example, the following aspects.

[0077] (Appendix 1)

[0078] A plasma processing chamber adjusted to a pressure within the range of 1 mTorr to 20 mTorr, and

[0079] A substrate support member disposed within the above plasma processing chamber, including a lower electrode, and supporting a substrate, and

[0080] An upper electrode disposed above the substrate support, and

[0081] An electromagnet having at least two annular coils arranged in a concentric shape, and

[0082] A first RF power source that supplies a source RF signal having a first RF frequency to the upper electrode, and

[0083] A second RF power supply that supplies a bias RF signal having a second RF frequency to the lower electrode, and

[0084] It is equipped with a control unit, and

[0085] The above control unit is,

[0086] A process of generating plasma within the plasma processing chamber by supplying the source RF signal to the upper electrode while the electromagnet generates a magnetic field within the plasma processing chamber, and depositing a deposit on the substrate;

[0087] With the electromagnet generating a magnetic field within the plasma processing chamber, the source RF signal is supplied to the upper electrode to generate plasma within the plasma processing chamber, and the process of etching the substrate is repeated.

[0088] A substrate processing apparatus in which the power level of the source RF signal in the process of etching the substrate is lower than the power level of the source RF signal in the process of depositing the deposit on the substrate.

[0089] (Appendix 2)

[0090] In Book 1,

[0091] A substrate processing apparatus in which the power level of the bias RF signal in the process of etching the substrate is higher than the power level of the bias RF signal in the process of depositing the deposit on the substrate.

[0092] (Appendix 3)

[0093] In Book 1 or Book 2,

[0094] The process of depositing the above-mentioned deposit on the above-mentioned substrate has a first period and a second period, and

[0095] The process of etching the above substrate has a third period and a fourth period, and

[0096] The power level of the source RF signal is a first power level in the first period, a second power level in the second period, a third power level in the third period, and a fourth power level in the fourth period, and

[0097] A substrate processing device in which the power level of the bias RF signal is a fifth power level in the first period, a sixth power level in the second period, a seventh power level in the third period, and an eighth power level in the fourth period.

[0098] (Appendix 4)

[0099] In any one of Books 1 to 3,

[0100] The above second power level is the same as the above first power level, and

[0101] The above third power level is smaller than the above second power level, and

[0102] The above-mentioned fourth power level is the same as the above-mentioned third power level, and

[0103] The above 6th power level is greater than the above 5th power level, and

[0104] The above seventh power level is greater than the above sixth power level, and

[0105] A substrate processing device in which the above 8th power level is greater than the above 7th power level.

[0106] (Appendix 5)

[0107] In Book 4,

[0108] A substrate processing device in which the above-mentioned fifth power level is 0[W].

[0109] (Appendix 6)

[0110] In any one of Books 1 to 5,

[0111] The above electromagnet is a substrate processing device in which currents flow in opposite directions in the coils adjacent to each other in the diameter direction.

[0112] (Appendix 7)

[0113] In any one of Books 1 to 6,

[0114] A substrate processing device in which the pressure inside the plasma processing chamber is within the range of 1 mTorr to 10 mTorr.

[0115] (Appendix 8)

[0116] In any one of Books 1 to 6,

[0117] A substrate processing device in which the pressure inside the plasma processing chamber is within the range of 3 mTorr to 8 mTorr.

[0118] (Appendix 9)

[0119] A substrate processing method of a substrate processing apparatus comprising: a plasma processing chamber adjusted to a pressure within the range of 1 mTorr to 20 mTorr; a substrate support member disposed within the plasma processing chamber and including a lower electrode and supporting a substrate; an upper electrode disposed above the substrate support member; an electromagnet having at least two annular coils arranged concentrically; a first RF power supply that supplies a source RF signal having a first RF frequency to the upper electrode; and a second RF power supply that supplies a bias RF signal having a second RF frequency to the lower electrode.

[0120] A process of generating plasma within the plasma processing chamber by supplying the source RF signal to the upper electrode while the electromagnet generates a magnetic field within the plasma processing chamber, and depositing a deposit on the substrate;

[0121] With the electromagnet generating a magnetic field within the plasma processing chamber, the source RF signal is supplied to the upper electrode to generate plasma within the plasma processing chamber, and the process of etching the substrate is repeated.

[0122] A substrate processing method in which the power level of the source RF signal in the process of etching the substrate is lower than the power level of the source RF signal in the process of depositing the deposit on the substrate.

[0123] For reference, the present invention is not limited to the configurations described in the above embodiments, such as combinations with other elements. Regarding this, modifications are possible within the scope that does not deviate from the spirit of the present invention, and can be appropriately determined according to the application form.

[0124] In addition, this application claims priority based on Japanese patent application No. 2023-197225 filed on November 21, 2023, and incorporates the entire contents of said Japanese patent application by reference herein. Explanation of the symbols

[0125] W substrate 1 Plasma processing device 2 control unit 10 Plasma treatment chamber 10a side wall 10s Plasma processing space 11 Substrate support (lower electrode) 13 Shower head (upper electrode) 20 Gas supply unit 30 everyone 31 RF power 31a 1st RF generation unit (1st RF power supply) 31b 2nd RF generation unit (2nd RF power supply) 40 exhaust system 510 Etching target film 520 mask 530 deposit 50 magnetic field generating unit 51 electromagnet 511~514 coil 52,521,522 everyone

Claims

Claim 1 A plasma processing chamber adjusted to a pressure within the range of 1 mTorr to 20 mTorr; a substrate support member disposed within the plasma processing chamber and including a lower electrode and supporting a substrate; an upper electrode disposed above the substrate support member; an electromagnet having at least two annular coils arranged concentrically; a first RF power supply that supplies a source RF signal having a first RF frequency to the upper electrode; a second RF power supply that supplies a bias RF signal having a second RF frequency to the lower electrode; and a control unit. The control unit repeats the process of generating plasma within the plasma processing chamber and depositing a deposit on the substrate by supplying the source RF signal to the upper electrode while the electromagnet generates a magnetic field within the plasma processing chamber, and generating plasma within the plasma processing chamber by supplying the source RF signal to the upper electrode while the electromagnet generates a magnetic field within the plasma processing chamber, and etching the substrate. In the process of etching the substrate, the power level of the source RF signal is such that the deposit on the substrate A substrate processing device having a power level lower than that of the source RF signal in the deposition process. Claim 2 A substrate processing apparatus according to claim 1, wherein the power level of the bias RF signal in the process of etching the substrate is higher than the power level of the bias RF signal in the process of depositing the deposit on the substrate. Claim 3 A substrate processing apparatus according to claim 1, wherein the process of depositing the deposited material on the substrate has a first period and a second period, the process of etching the substrate has a third period and a fourth period, the power level of the source RF signal is a first power level in the first period, a second power level in the second period, a third power level in the third period, and a fourth power level in the fourth period, and the power level of the bias RF signal is a fifth power level in the first period, a sixth power level in the second period, a seventh power level in the third period, and an eighth power level in the fourth period. Claim 4 A substrate processing device according to paragraph 3, wherein the second power level is the same as the first power level, the third power level is smaller than the second power level, the fourth power level is the same as the third power level, the sixth power level is larger than the fifth power level, the seventh power level is larger than the sixth power level, and the eighth power level is larger than the seventh power level. Claim 5 A substrate processing device according to claim 4, wherein the fifth power level is 0[W]. Claim 6 A substrate processing device according to any one of claims 1 to 5, wherein the electromagnet has currents flowing in opposite directions in the coils adjacent in the diameter direction. Claim 7 A substrate processing apparatus according to any one of claims 1 to 5, wherein the pressure inside the plasma processing chamber is within the range of 1 mTorr to 10 mTorr. Claim 8 A substrate processing apparatus according to any one of claims 1 to 5, wherein the pressure inside the plasma processing chamber is within the range of 3 mTorr to 8 mTorr. Claim 9 A substrate processing method of a substrate processing apparatus comprising: a plasma processing chamber adjusted to a pressure within the range of 1 mTorr to 20 mTorr; a substrate support member disposed within the plasma processing chamber and including a lower electrode and supporting a substrate; an upper electrode disposed above the substrate support member; an electromagnet having at least two annular coils arranged concentrically; a first RF power supply supplying a source RF signal having a first RF frequency to the upper electrode; and a second RF power supply supplying a bias RF signal having a second RF frequency to the lower electrode, wherein the electromagnet generates a magnetic field within the plasma processing chamber, the source RF signal is supplied to the upper electrode to generate plasma within the plasma processing chamber and deposit a deposit on the substrate; and the process of repeating the process of generating plasma within the plasma processing chamber by supplying the source RF signal to the upper electrode while the electromagnet generates a magnetic field within the plasma processing chamber and etching the substrate, wherein the power level of the source RF signal in the process of etching the substrate is such that the deposit on the substrate A substrate processing method that is lower than the power level of the source RF signal in the deposition process.

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