Substrate processing method and substrate processing device

Abstract

The present invention provides a technology for controlling formation of film on the surface of a recess in an etching target film. This substrate processing method comprises: (a) a step for providing, on a substrate support in a chamber, a substrate including an etching target film having a recess; (b) a step for exposing the substrate to a first processing gas containing a first halogen and hydrogen, to form, on the surface of the recess, a first layer that includes at least one of a halogenated surface and a surface to which hydrogen halide is adsorbed; and (c) a step for exposing the substrate to plasma generated from a second processing gas containing a second halogen and a group-14 element, to form, on the surface of the recess, a second layer containing the second halogen and the group-14 element.

Description

Substrate processing method and substrate processing apparatus

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

[0002] Japanese Patent Application Laid-Open No. 2003-144222 discloses a technique for forming a carbon film on the surface of a recess in a film to be etched.

[0003] Japanese Patent Application Laid-Open No. 2016-21546

[0004] The present disclosure provides a technique for controlling film formation on the surface of a recess in a film to be etched.

[0005] In one exemplary embodiment of the present disclosure, a substrate processing method includes: (a) providing a substrate including a film to be etched having a recess on a substrate support in a chamber; (b) exposing the substrate to a first process gas including a first halogen and hydrogen to form a first layer on a surface of the recess, the first layer including at least one of a halogenated surface and a surface having hydrogen halide adsorbed thereon; and (c) exposing the substrate to plasma generated from a second process gas including a second halogen and a Group 14 element to form a second layer including the second halogen and the Group 14 element on the surface of the recess.

[0006] According to one exemplary embodiment of the present disclosure, a technique for controlling film formation on the surface of a recessed portion of a film to be etched can be provided.

[0007] FIG. 1 is a diagram for explaining an example of the configuration of a plasma processing system; FIG. 2 is a diagram for explaining an example of the configuration of an inductively coupled plasma processing apparatus; FIG. 3 is a flowchart showing an example of a substrate processing method; FIG. 4 is a diagram showing an example of a cross-sectional structure of a substrate in process ST1; FIG. 5 is a diagram showing an example of a cross-sectional structure of a substrate in process ST2; FIG. 6 is a diagram showing an example of a cross-sectional structure of a substrate in process ST3; and FIG. 7 is a diagram showing an example of a cross-sectional structure of a substrate in process ST4.

[0008] Hereinafter, each embodiment of the present disclosure will be described.

[0009] In one exemplary embodiment, a substrate processing method is provided, comprising: (a) providing a substrate including a film to be etched having a recess on a substrate support in a chamber; (b) exposing the substrate to a first process gas including a first halogen and hydrogen to form a first layer on a surface of the recess, the first layer including at least one of a halogenated surface and a surface having hydrogen halide adsorbed thereon; and (c) exposing the substrate to a plasma generated from a second process gas including a second halogen and a Group 14 element to form a second layer including the second halogen and the Group 14 element on the surface of the recess.

[0010] In one exemplary embodiment, the surface of the recess includes a first region and a second region above the first region, and the thickness of the second layer formed in the first region is greater than the thickness of the second layer formed in the second region.

[0011] In one exemplary embodiment, the first region includes a surface of the bottom of the recess, and the second region includes a surface of the sidewall of the recess.

[0012] In one exemplary embodiment, in step (b), the temperature of the substrate support or the temperature of the substrate is controlled to 250° C. or less.

[0013] In one exemplary embodiment, step (c) provides a bias signal to the substrate support.

[0014] In one exemplary embodiment, in step (b), a plasma is formed from the first process gas and no bias signal is applied to the substrate support.

[0015] In one exemplary embodiment, the method further includes the step of (d) etching the target film after the step (c).

[0016] In one exemplary embodiment, the cycle comprising steps (c) and (d) is repeated.

[0017] In one exemplary embodiment, the first process gas includes at least one selected from the group consisting of HF gas, HCl gas, HBr gas, and HI gas.

[0018] In one exemplary embodiment, the second process gas includes at least one selected from the group consisting of a CF-based gas, a CHF-based gas, a CBr-based gas, a CHBr-based gas, a CCl-based gas, a CHCl-based gas, a CI-based gas, a CHI-based gas, and a SiCl-based gas.

[0019] In one exemplary embodiment, the film to be etched is a film containing at least one selected from the group consisting of silicon, carbon, and metal.

[0020] In one exemplary embodiment, in step (c), 10 １５ / m 3 The substrate is exposed to a plasma having a high electron density equal to or higher than this.

[0021] In one exemplary embodiment, the film to be etched has a plurality of recesses with different width dimensions.

[0022] In one exemplary embodiment, the recess in the film to be etched has a trench or hole shape.

[0023] In one exemplary embodiment, there is provided a substrate processing apparatus including a chamber, a substrate support disposed within the chamber, a plasma generator, and a controller, wherein the controller is configured to: (a) provide a substrate including a film to be etched having a recess on the substrate support within the chamber; (b) expose the substrate to a first process gas including a first halogen and hydrogen to form a first layer on a surface of the recess, the first layer including at least one of a halogenated surface and a surface having hydrogen halide adsorbed thereon; and (c) expose the substrate to plasma generated from a second process gas including a second halogen and a Group 14 element to form a second layer including the second halogen and the Group 14 element on the surface of the recess.

[0024] Hereinafter, each embodiment of the present disclosure will be described in detail with reference to the drawings. In each drawing, the same or similar elements are designated by the same reference numerals, and redundant explanations will be omitted. Unless otherwise specified, the positional relationships, such as up, down, left, and right, will be described based on the positional relationships shown in the drawings. The dimensional ratios in the drawings do not represent actual ratios, and the actual ratios are not limited to the ratios shown in the drawings.

[0025] <Example of Plasma Processing System> FIG. 1 is a diagram illustrating an example of the 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 11, and a plasma generation unit 12. The plasma processing chamber 10 has a plasma processing space. The plasma processing chamber 10 also has at least one gas supply port for supplying at least one processing gas to the plasma processing space and at least one gas exhaust port for exhausting gas from the plasma processing space. The gas supply port is connected to a gas supply unit 20 (described later), and the gas exhaust port is connected to an exhaust system 40 (described later). The substrate support 11 is disposed in the plasma processing space and has a substrate support surface for supporting a substrate.

[0026] The plasma generating unit 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma generated in the plasma processing space may be capacitively coupled plasma (CCP), inductively coupled plasma (ICP), electron-cyclotron-resonance plasma (ECR plasma), helicon wave plasma (HWP), surface wave plasma (SWP), or the like. Various types of plasma generators may be used, including alternating current (AC) plasma generators and direct current (DC) plasma generators. In one embodiment, the AC signal (AC power) used in the AC plasma generator has a frequency in the range of 100 kHz to 10 GHz. Thus, AC signals include radio frequency (RF) signals and microwave signals. In one embodiment, the RF signal has a frequency in the range of 100 kHz to 150 MHz.

[0027] The controller 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to perform various processes described in this disclosure. The controller 2 may be configured to control each element of the plasma processing apparatus 1 to perform various processes described herein. In one embodiment, part or all of the controller 2 may be included in the plasma processing apparatus 1. The controller 2 may include, for example, a computer 2a. The computer 2a may include, for example, a processing unit (CPU: Central Processing Unit) 2a1, a storage unit 2a2, and a communication interface 2a3. The processing unit 2a1 may be configured to read a program from the storage unit 2a2 and execute the read program to perform various control operations. The program may be stored in the storage unit 2a2 in advance or may be acquired via a medium when needed. The acquired program is stored in the storage unit 2a2 and read from the storage unit 2a2 by the processing unit 2a1 for execution. The medium may be various storage media readable by the computer 2a or a communication line connected to the communication interface 2a3. The storage unit 2a2 may include a random access memory (RAM), a read-only memory (ROM), a hard disk drive (HDD), a solid state drive (SSD), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing apparatus 1 via a communication line such as a local area network (LAN).

[0028] An example of the configuration of an inductively coupled plasma processing apparatus will be described below as an example of the plasma processing apparatus 1. FIG. 2 is a diagram illustrating the configuration of an inductively coupled plasma processing apparatus. The inductively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply 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 11, a gas inlet unit, and an antenna 14. The substrate support 11 is disposed within the plasma processing chamber 10. The antenna 14 is disposed 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, a sidewall 102 of the plasma processing chamber 10, and the substrate support 11. The plasma processing chamber 10 is grounded.

[0029] The substrate support 11 includes a main body 111 and a ring assembly 112. The main body 111 has a central region 111a for supporting a substrate W and an annular region 111b for supporting the ring assembly 112. A wafer is an example of a substrate W. The annular region 111b of the main body 111 surrounds the central region 111a of the main body 111 in a plan view. The substrate W is disposed on the central region 111a of the main body 111, and the ring assembly 112 is disposed on the annular region 111b of the main body 111 so as to surround the substrate W on the central region 111a of the main body 111. Therefore, the central region 111a is also called a substrate support surface for supporting the substrate W, and the annular region 111b is also called a ring support surface for supporting the ring assembly 112.

[0030] 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 disposed on the base 1110. The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic electrode 1111b disposed within the ceramic member 1111a. The ceramic member 1111a has a central region 111a. In one embodiment, the ceramic member 1111a also has an annular region 111b. Note that the annular region 111b may also be provided by another member surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member. In this case, the ring assembly 112 may be disposed on the annular electrostatic chuck or the annular insulating member, or may be disposed on both the electrostatic chuck 1111 and the annular insulating member. Alternatively, an RF or DC electrode may be disposed within the ceramic member 1111a, in which case the RF or DC electrode functions as a bias electrode. Note that both the conductive member of the base 1110 and the RF or DC electrode may function as two bias electrodes.

[0031] The ring assembly 112 includes one or more annular members. In one embodiment, the one or more annular members include one or more edge rings and at least one cover ring. The edge rings are formed of a conductive or insulating material, and the cover rings are formed of an insulating material.

[0032] The substrate support 11 may also include a temperature adjustment module configured to adjust at least one of the electrostatic chuck 1111, the ring assembly 112, and the substrate to a target temperature. The temperature adjustment module may include a heater, a heat transfer medium, a flow passage 1110a, or a combination thereof. A heat transfer fluid such as brine or a gas flows through the flow passage 1110a. In one embodiment, the flow passage 1110a is formed in the base 1110, and one or more heaters are disposed in the ceramic member 1111a of the electrostatic chuck 1111. The substrate support 11 may also include a heat transfer gas supply configured to supply a heat transfer gas between the backside of the substrate W and the central region 111a.

[0033] The gas inlet is configured to introduce at least one process gas from the gas supply unit 20 into the plasma processing space 10s. In one embodiment, the gas inlet includes a center gas injector (CGI) 13. The center gas injector 13 is disposed above the substrate support 11 and attached to a central opening formed in the dielectric window 101. The center gas injector 13 has at least one gas supply port 13a, at least one gas flow path 13b, and at least one gas inlet port 13c. The process 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 inlet port 13c. Note that the gas inlet may include one or more side gas injectors (SGIs) attached to one or more openings formed in the sidewall 102 in addition to or instead of the center gas injector 13.

[0034] The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one process gas from a corresponding gas source 21 to the gas inlet through a corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, the gas supply unit 20 may include at least one flow modulation device that modulates or pulses the flow rate of the at least one process gas.

[0035] The power supply 30 includes an RF power supply 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply 31 is configured to supply at least one RF signal (RF power), such as a source RF signal and a bias RF signal, to at least one bias electrode and the antenna 14. This causes a plasma to be 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 a part of the plasma generating unit 12. Furthermore, by supplying a bias RF signal to the at least one bias electrode, a bias potential is generated on the substrate W, thereby attracting ions in the formed plasma to the substrate W.

[0036] In one embodiment, the RF power supply 31 includes a first RF generating unit 31a and a second RF generating unit 31b. The first RF generating unit 31a is coupled to the antenna 14 via at least one impedance matching circuit and is configured to generate a source RF signal (source RF power) for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 10 MHz to 150 MHz. In one embodiment, the first RF generating unit 31a may be configured to generate multiple source RF signals having different frequencies. The generated one or more source RF signals are supplied to the antenna 14.

[0037] The second RF generator 31b is coupled to at least one bias electrode via at least one impedance matching circuit and is configured to generate a bias RF signal (bias RF power). The frequency of the bias RF signal may be the same as or different from the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency lower than the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 100 kHz to 60 MHz. In one embodiment, the second RF generator 31b may be configured to generate multiple bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to at least one bias electrode. In various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0038] The power supply 30 may also include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a bias DC generator 32a. In one embodiment, the bias DC generator 32a is connected to at least one bias electrode and configured to generate a bias DC signal. The generated bias DC signal is applied to the at least one bias electrode.

[0039] In various embodiments, the bias DC signal may be pulsed. In this case, a sequence of DC-based voltage pulses is applied to at least one bias electrode. The voltage pulses may have a rectangular, trapezoidal, triangular, or combination thereof. In one embodiment, a waveform generator for generating the sequence of voltage pulses from the DC signal is connected between the bias DC generator 32a and at least one bias electrode. Thus, the bias DC generator 32a and the waveform generator constitute a voltage pulse generator. The voltage pulses 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 bias DC generator 32a may be provided in addition to the RF power supply 31 or may be provided instead of the second RF generator 31b.

[0040] 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 RF 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 generator may be connected to both the outer coil and the inner coil, or separate RF generators may be connected to the outer coil and the inner coil separately.

[0041] The exhaust system 40 may be connected to, for example, a gas exhaust port 10e provided at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure in 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.

[0042] <Example of Substrate Processing Method> Figure 3 is a flowchart showing an example of a substrate processing method (hereinafter also referred to as "this processing method") according to an illustrative embodiment. As shown in Figure 3, in one embodiment, this processing method includes a step ST1 of providing a substrate, a step ST2 of forming a first layer in a recess of the substrate, a step ST3 of forming a second layer in the recess of the substrate, and an etching step ST4. The processing in each step may be performed in the plasma processing system shown in Figure 2. Below, an example will be described in which the control unit 2 controls each part of the plasma processing apparatus 1 to perform this processing method on a substrate W.

[0043] (Process ST1: Providing a Substrate) In process ST1, a substrate W is provided to a plasma processing chamber 10 (hereinafter also referred to as "chamber 10") as shown in Fig. 2. In one embodiment, the substrate W is carried into the chamber 10 by a transport arm, placed on a substrate support 11 by a lifter, and held on the substrate support 11 by suction.

[0044] 4 is a diagram showing an example of the cross-sectional structure of a substrate W. The substrate W has an etching target film EF and a mask MK stacked in this order from bottom to top on an undercoat film UF. The substrate W may be used for manufacturing semiconductor devices. Semiconductor devices include, for example, memory devices such as DRAMs and 3D-NAND flash memories, and logic devices.

[0045] The mask MK may be a film that functions as a mask in etching the etching target film EF. The mask MK may have a sidewall S1 that defines at least one opening OP1 on the etching target film EF. That is, the mask MK may have an opening OP1. The opening OP1 may be a space above a recess R1 in the etching target film EF and may be surrounded by the sidewall S1 of the mask MK.

[0046] The opening OP1 may have any shape when viewed from above the substrate W, i.e., when the substrate W is viewed from top to bottom in FIG. 4 . The shape may be, for example, a circle, an ellipse, a rectangle, a line, or a combination of one or more of these. The mask MK may have multiple side walls S1, and the multiple side walls S1 may define multiple openings OP1. The multiple openings OP1 may each have a linear shape and be arranged at regular or varying intervals to form a line-and-space pattern. Alternatively, the multiple openings OP1 may each have a hole shape and form an array pattern.

[0047] The mask MK may be a film containing at least one selected from the group consisting of silicon, carbon, and metal. The silicon-containing film may be a silicon oxide film, a silicon nitride film, a silicon carbonitride film, a polycrystalline silicon film, or a carbon-containing silicon film. The silicon-containing film may be doped with elements such as phosphorus, boron, or nitrogen. The carbon-containing film may be a spin-on carbon (SOC) film, an amorphous carbon (ACL) film, a photoresist film, a tungsten carbide film, or a boron carbide film. The metal-containing film may be a film containing at least one metal selected from the group consisting of tungsten, molybdenum, ruthenium, titanium, and aluminum. The mask MK may be a single-layer mask consisting of one layer, or a multi-layer mask consisting of two or more layers.

[0048] The etching target film EF may have at least one recess R1. The recess R1 may be arranged to correspond to the opening OP1 of the mask MK. The recess R1 may have a sidewall S2 and a bottom B2. The etching target film EF may have a plurality of recesses R1 with different widths. The plurality of recesses R1 may include some with a relatively wide width and some with a relatively narrow width. The recess R1 may have a trench shape or a hole shape.

[0049] The etching target film EF may be a film containing at least one selected from the group consisting of silicon, carbon, and metal. The silicon-containing film may be a silicon oxide film, a silicon nitride film, a silicon carbonitride film, a polycrystalline silicon film, or a carbon-containing silicon film. The silicon-containing film may be doped with elements such as phosphorus, boron, or nitrogen. The carbon-containing film may be a spin-on carbon (SOC) film, an amorphous carbon (ACL) film, a photoresist film, a tungsten carbide film, or a boron carbide film. The metal-containing film may be a film containing at least one metal selected from the group consisting of tungsten, molybdenum, ruthenium, titanium, and aluminum.

[0050] The base film UF may be a silicon wafer, an organic film formed on a silicon wafer, a dielectric film, a metal film, a semiconductor film, etc. The base film UF may be configured by laminating a plurality of films.

[0051] Each film constituting the substrate W may be formed by any method. The base film UF, etching target film EF, and mask MK may be formed by a CVD method, an ALD method, a PVD method, a spin coating method, or the like. The opening OP1 in the mask MK and the recess R1 in the etching target film EF may be formed by etching. The opening OP1 in the mask MK and the recess R1 in the etching target film EF may be formed by a lithography method. Note that each film may be a flat film or may have an uneven surface. The substrate W may further include another film below the base film UF.

[0052] At least a part of the process of forming the base film UF, the etching target film EF, and the mask MK of the substrate W may be performed in the chamber 10 as part of step ST1. For example, the opening OP1 in the mask MK and / or the recess R1 in the etching target film EF may be formed by etching in step ST1. In this case, the etching of the mask MK and / or the etching target film EF in step ST1 and steps ST2, ST3, and ST4 described below may be performed consecutively in the chamber 10. In one embodiment, all or part of the film on the substrate W may be formed in an apparatus or chamber external to the plasma processing apparatus 1, and then the substrate W may be provided in the chamber 10.

[0053] In one embodiment, after the substrate W is provided on the substrate support 11, the temperature of the substrate support 11 or the substrate W is controlled to a given temperature by a temperature control module. Controlling the temperature of the substrate support 11 or the substrate W to a given temperature may include setting the temperature of the heat transfer fluid flowing through the flow path 1110a or the heater temperature to a given temperature, or setting them to a temperature different from the given temperature. The given temperature may be, for example, 50°C or lower or -50°C or higher. The given temperature may be room temperature (e.g., 25°C) or lower or 0°C or lower. The timing at which the temperature of the substrate support 11 or the substrate W starts to be controlled to a given temperature may be before or after the substrate W is placed on the substrate support 11, or may be simultaneous with the placement of the substrate W on the substrate support 11. The temperature of the substrate support 11 or the substrate W may be changed in each of the processes ST1 to ST4.

[0054] 5 is a diagram illustrating an example of a cross-sectional structure of a substrate W on which a first layer L1 is formed on the surface of the recess R1 of the etching target film EF in step ST2. In one embodiment, in step ST2, the substrate W is exposed to a first process gas to form the first layer L1 on the surface of the recess R1.

[0055] In one embodiment, in step ST2, a first process gas is supplied into the chamber 10 from the central gas inlet 13 shown in FIG. 2 . The temperature of the substrate support 11 or the substrate W may be controlled to a first temperature. The first temperature may be in the range of −70° C. to 250° C. The first temperature may be 10° C. or less, or 0° C. or less. The pressure in the chamber 10 may be adjusted to a first pressure. The first pressure may be in the range of 1 mTorr to 1000 mTorr, or in the range of 1 mTorr to 100 mTorr.

[0056] The first process gas may be a gas containing a first halogen and hydrogen. The first halogen may be any of F, Cl, Br, and I. The first process gas may contain a hydrogen halide. The first process gas may contain at least one hydrogen halide selected from the group consisting of HF gas, HCl gas, HBr gas, and HI gas. The first process gas may be a gas containing a single gas of the first halogen and a single gas of hydrogen. The first process gas may further contain an inert gas. The inert gas may be a noble gas such as Ar gas, He gas, or Kr gas, or N ２ It may be a gas.

[0057] The substrate W in the chamber 10 is exposed to a first process gas, and as shown in FIG. 5 , a first layer L1 is formed on the surface of the recess R1. The first layer L1 is formed by halogenating the surface of the recess R1 and / or by adsorbing hydrogen halide to the surface of the recess R1. The first layer L1 may include at least one of a halogenated surface and a surface to which hydrogen halide is adsorbed. The first layer L1 can suppress the chemisorption of dissociated neutral species in the plasma and the generation of polymers thereof.

[0058] In step ST2, the first process gas to which the substrate W is exposed does not have to be in a plasma state. That is, plasma does not have to be generated from the first process gas supplied into the chamber 10. On the other hand, in step ST2, the first process gas to which the substrate W is exposed may be in a plasma state. That is, plasma may be generated from the first process gas supplied into the chamber 10 in step ST2. In this case, a source RF signal is supplied from the first RF generator 31a to the antenna 14. This generates a high-frequency electric field between the antenna 14 and the substrate support 11, and plasma is generated from the process gas in the plasma processing space 10s. At this time, a bias signal does not have to be supplied to the substrate support 11.

[0059] 6 is a diagram illustrating an example of a cross-sectional structure of a substrate W on which a second layer L2 is formed on the surface of the recess R1 of the etching target film EF in step ST3. In one embodiment, in step ST3, the substrate W is exposed to plasma generated from a second process gas, so that the second layer L2 is formed on the surface of the recess R1.

[0060] In one embodiment, in step ST3, a second process gas is supplied into the chamber 10 from the central gas inlet 13 shown in FIG. 2 . The temperature of the substrate support 11 or the substrate W may be controlled to a second temperature. The second temperature may be in a range of 250° C. or less and −70° C. or more, or in a range of 80° C. or less and 0° C. or more. The second temperature may be higher than the first temperature. The pressure in the chamber 10 may be adjusted to a second pressure. The second pressure may be in a range of 1 mTorr or more and 10,000 mTorr or less, or in a range of 50 mTorr or more and 500 mTorr or less. The second pressure may be higher than the first pressure.

[0061] The second process gas may be a gas containing a second halogen and a Group 14 element. The second halogen may be any of F, Cl, Br, and I. The second halogen contained in the second process gas may be the same as or different from the first halogen contained in the first process gas. The Group 14 element may be any of C, Si, Ge, and Sn. The second process gas may contain at least one gas selected from the group consisting of a CF-based gas, a CHF-based gas, a CBr-based gas, a CHBr-based gas, a CCl-based gas, a CHCl-based gas, a CI-based gas, a CHI-based gas, and a SiCl-based gas. The CF-based gas (fluorocarbon gas) may be CF ４ Gas, C ２ F ２ Gas, C ２ F ４ Gas, C ３ F ６ Gas, C ３ F ８ Gas, C ４ F ６ Gas, C ４ F ８ Gas and C ５ F ８ The CHF-based (hydrofluorocarbon gas) may contain at least one selected from the group consisting of CH ２ F ２ Gas, CH ３ F gas and CHF ３ The CCl-based gas may contain at least one selected from the group consisting of CCl ４ The CHCl-based gas may include CHCl ３ Gas, CH ２ Cl ２ Gas and CH ３ The CI-based gas may contain at least one selected from CI gas. ４ The CHI-based gas may include CHI ３ Gas, CH ２ I ２ Gas and CH ３ The CBr-based gas may contain at least one selected from the group consisting of CBr, ４ The CHBr-based gas may include CHBr ３ Gas, CH ２ Br２ Gas and CH ３ The second process gas may contain at least one selected from the group consisting of Br gas, Ar gas, and Br gas. The C-containing gas may contain Si, Ge, or Sn instead of C. The second process gas may contain a gas represented by Xn-Hm-Yl (X=C, Si, Ge, Sn, Y=F, Cl, Br, I, n, m, and l are integers of 0 or more). The second process gas may further contain an inert gas. The inert gas may be a noble gas such as Ar gas, He gas, or Kr gas, or N ２ It may be a gas.

[0062] In one embodiment, plasma is generated from the second process gas supplied into the chamber 10. In this case, a source RF signal is supplied from the first RF generator 31a to the antenna 14, which generates a high-frequency electric field between the antenna 14 and the substrate support 11, generating plasma from the process gas in the plasma processing space 10s. The source RF signal may have a power of 1 kW or more. The source RF signal may have a power of 1 kW or more and 10 kW or less. The plasma is generated at 10 kW or less. １５ / m ３ may have a high electron density of 10 or more; １７ / m 3 The electron density may be as high as or higher than 100 keV.

[0063] The first layer L1 is modified by ions and dissociated neutral species in the plasma, and a second layer L2 is formed on the surface of the recess R1 as shown in Fig. 6. The second layer L2 can be a protective film containing a second halogen and a Group 14 element.

[0064] When plasma is generated, a bias signal may be supplied to the substrate support 11. The bias signal may be a bias RF signal supplied from the RF power supply 31 or a bias DC signal supplied from the DC power supply 32. In this case, a bias potential is generated between the plasma and the substrate W. Ions and dissociated neutral species in the plasma are attracted to the substrate W and supplied into the recess R1.

[0065] Ions of atoms and molecules containing Group 14 elements and dissociated neutral species in the plasma are supplied to the recess R1 in a state where chemical adsorption and generation of polymerized species are suppressed by the hydrogen halide of the first layer L1. Many of the ions in the plasma that are not consumed by the sidewall S2 of the recess R1 can reach and be deposited on the bottom B2 of the recess R1.

[0066] For example, a second layer L2 that is thicker than the sidewall S2 is formed on the bottom B2 of the recess R1.

[0067] 7 is a diagram illustrating an example of a cross-sectional structure of a substrate W in which a recess R1 in the etching target film EF is etched in step ST4. In one embodiment, in step ST4, the recess R1 in the etching target film EF is etched. As a result, etching of the bottom B2 of the recess R1 progresses in the depth direction, and a deeper recess R1 is formed in the etching target film EF. Furthermore, an opening may be formed in the etching target film EF, and the base film UF may be exposed in the opening.

[0068] In one embodiment, in step ST4, an etching gas is supplied into the chamber 10 from the central gas inlet 13 shown in FIG. 2. The etching gas may include a gas containing carbon and fluorine. The CF-based gas (fluorocarbon gas) is a CF-based gas containing C ４ F ６ Gas, C ４ F ８ Gas, C ３ F ８ Gas, CF ４ Gas, C ２ F ２ Gas, C ２ F ４ Gas, C ３ F ６ Gas and C ５ F ８ The CHF-based gas (hydrofluorocarbon gas) may be at least one selected from the group consisting of CHF ３ Gas, CH ２ F ２ Gas, CH ３ F gas, C ３ H ２ F ４ Gas, C ４ H ２F ６ Gas, C ２ HF ５ Gas, C ２ H ２ F ４ Gas, C ２ H ３ F ３ Gas, C ２ H ４ F ２ Gas, C ３ HF ７ Gas, C ３ H ２ F ２ Gas, C ３ H ２ F ６ Gas, C ３ H ３ F ５ Gas, C ４ H ５ F ５ Gas, C ４ H ２ F ８ Gas, C ５ H ２ F ６ Gas, C ５ H ２ F １０ Gas and C ５ H ３ F ７ The gas may be at least one selected from the group consisting of gases.

[0069] Plasma may be generated from the etching gas supplied into the chamber 10. In this case, a source RF signal is supplied to the antenna 14, which generates a high-frequency electric field between the antenna 14 and the substrate support 11, generating plasma from the processing gas in the plasma processing space 10s. At this time, a bias signal may be supplied to the substrate support 11. The bias signal may be a bias RF signal supplied from the RF power supply 31 or a bias DC signal supplied from the DC power supply 32. In this case, a bias potential is generated between the plasma and the substrate W. Active species such as ions and radicals in the plasma are attracted to the substrate W, and the bottom B2 of the recess R1 in the etching target film EF is etched in the depth direction by the active species.

[0070] After the process ST4, the substrate W may be transferred from the chamber 10 to the outside. In one embodiment, the substrate W may be transferred from the substrate support 11 to the outside of the chamber 10 by a lifter and a transport arm.

[0071] Step ST2 and step ST3 may be performed as separate steps, and in one example, may be performed consecutively, or may be performed simultaneously.

[0072] In this processing method, a cycle including steps S3 and S4 may be repeated a predetermined number of times. Furthermore, in this processing method, a cycle including steps S2, S3, and S4 may be repeated a predetermined number of times.

[0073] According to this exemplary embodiment, the substrate processing method includes: (a) providing a substrate W including an etching target film EF on a substrate support 11 in a chamber 10 (step ST1), (b) exposing the substrate W to a first process gas including a first halogen and hydrogen to form a first layer L1 on the surface of the recess R1 (step ST2), and (c) exposing the substrate W to plasma generated from a second process gas including a second halogen and a Group 14 element to form a second layer L2 including the second halogen and the Group 14 element in the recess R1 (step ST3). In step ST2, the first layer L1 includes a halogenated surface and / or a surface to which hydrogen halide is adsorbed.

[0074] Forming a first layer L1 including a halogenated surface and / or a surface with hydrogen halide adsorbed thereon on the surface of the recess R1 of the substrate W can suppress the high probability of chemical adhesion of plasma ions and dissociated neutral species to the upper portion (e.g., sidewall) of the recess R1. Therefore, plasma ions and dissociated neutral species are supplied to the bottom B2 of the recess R1, allowing film formation at the bottom B2. This allows the thickness of the second layer L2 (the protective film thickness) at the bottom B2 to be appropriately formed regardless of the width (width dimension) or depth of the bottom B2. In other words, the dependence of the film thickness of the second layer L2 at the bottom B2 on the CD (line width) and aspect ratio of the film EF to be etched (CD (line width) dependence and aspect ratio dependence) can be reduced. Since the second layer L2 is secured at a deep position in the recess R1, bowing can be suppressed. This allows film formation on the surface of the recess of the film to be etched to be controlled.

[0075] According to this exemplary embodiment, in step ST2, the temperature of the substrate support 11 or the temperature of the substrate W is controlled to 50° C. or less. This increases the amount of hydrogen halide adsorbed to the surface of the recess R1, and as a result, in step ST3, it is possible to suppress chemical adhesion of dissociated neutral species of plasma to the sidewall of the recess R1 with a high probability.

[0076] According to this exemplary embodiment, in step ST3, a bias signal is supplied to the substrate support 11, so that anisotropic incidence of dissociated species of plasma is realized, and a film can be appropriately formed on the bottom B2 of the recess R1.

[0077] According to this exemplary embodiment, in step ST2, plasma is generated from the first process gas, and no bias signal is supplied to the substrate support 11. This increases the amount of hydrogen halide adsorbed to the upper portion (sidewall) of the recess R1, and as a result, in step ST3, it is possible to suppress chemical adhesion of dissociated neutral species of the plasma to the sidewall of the recess R1 with a high probability.

[0078] According to this exemplary embodiment, in step ST3, the substrate W is exposed to plasma with high electron density and high dissociation, so that a film can be appropriately formed on the bottom B2 of the recess R1.

[0079] In the above embodiments, the present processing method is not limited to an inductively coupled plasma processing apparatus, and may be performed in other types of plasma processing apparatuses, such as a plasma processing apparatus that generates capacitively coupled plasma, a plasma processing apparatus that generates ECR plasma, a plasma processing apparatus that generates helicon wave excited plasma, or a plasma processing apparatus that generates surface wave plasma.

[0080] The present disclosure may include, for example, the following configurations.

[0081] (Supplementary Note 1) A substrate processing method comprising: (a) providing a substrate including a film to be etched having a recess on a substrate support in a chamber; (b) exposing the substrate to a first process gas including a first halogen and hydrogen to form a first layer on a surface of the recess, the first layer including at least one of a halogenated surface and a surface having hydrogen halide adsorbed thereon; and (c) exposing the substrate to plasma generated from a second process gas including a second halogen and a Group 14 element to form a second layer including the second halogen and the Group 14 element on the surface of the recess.

[0082] (Supplementary Note 2) The substrate processing method according to Supplementary Note 1, wherein the surface of the recess includes a first region and a second region above the first region, and the thickness of the second layer formed in the first region is greater than the thickness of the second layer formed in the second region.

[0083] (Supplementary Note 3) The substrate processing method according to Supplementary Note 2, wherein the first region includes a surface of a bottom of the recess, and the second region includes a surface of a sidewall of the recess.

[0084] (Supplementary Note 4) The substrate processing method according to any one of Supplementary Notes 1 to 3, wherein in the step (b), the temperature of the substrate support part or the temperature of the substrate is controlled to 250° C. or less.

[0085] (Supplementary Note 5) The substrate processing method according to any one of Supplementary Notes 1 to 4, wherein in the step (c), a bias signal is supplied to the substrate support part.

[0086] (Supplementary Note 6) The substrate processing method according to any one of Supplementary Notes 1 to 5, wherein in the step (b), plasma is generated from the first processing gas, and a bias signal is not supplied to the substrate support.

[0087] (Supplementary Note 7) The substrate processing method according to any one of Supplementary Notes 1 to 6, further comprising the step of: (d) etching the etching target film after the step (c).

[0088] (Supplementary Note 8) The substrate processing method according to Supplementary Note 7, wherein a cycle including the steps (c) and (d) is repeated.

[0089] (Supplementary Note 9) The substrate processing method according to any one of Supplementary Notes 1 to 8, wherein the first processing gas includes at least one gas selected from the group consisting of HF gas, HCl gas, HBr gas, and HI gas.

[0090] (Supplementary Note 10) The substrate processing method according to any one of Supplementary Notes 1 to 9, wherein the second process gas includes at least one gas selected from the group consisting of a CF-based gas, a CHF-based gas, a CBr-based gas, a CHBr-based gas, a CCl-based gas, a CHCl-based gas, a CI-based gas, a CHI-based gas, and a SiCl-based gas.

[0091] (Supplementary Note 11) The substrate processing method according to any one of Supplementary Notes 1 to 10, wherein the etching target film is a film containing at least one selected from the group consisting of silicon, carbon, and metal.

[0092] (Note 12) In the step (c), 10 １５ / m 3 12. The substrate processing method according to claim 1, wherein the substrate is exposed to a plasma having a high electron density of at least 1000 kJ / cm.

[0093] (Supplementary Note 13) The substrate processing method according to any one of Supplementary Notes 1 to 12, wherein the etching target film has a plurality of the recesses having different width dimensions.

[0094] (Supplementary Note 14) The substrate processing method according to any one of Supplementary Notes 1 to 13, wherein the recess in the etching target film has a trench shape or a hole shape.

[0095] (Supplementary Note 15) A substrate processing apparatus comprising: a chamber, a substrate support part disposed in the chamber, a plasma generation part, and a control part, wherein the control part is configured to execute the following controls: (a) providing a substrate including a film to be etched having a recess on the substrate support part in the chamber; (b) exposing the substrate to a first process gas containing a first halogen and hydrogen to form a first layer on a surface of the recess, the first layer including at least one of a halogenated surface and a surface having hydrogen halide adsorbed thereon; and (c) exposing the substrate to plasma generated from a second process gas containing a second halogen and a Group 14 element to form a second layer including the second halogen and the Group 14 element on the surface of the recess.

[0096] In the above exemplary embodiments, the plasma processing apparatus and the plasma processing method may be modified in various ways without departing from the scope and spirit of the present disclosure. For example, some components in one embodiment may be added to other embodiments within the scope of the ordinary creativity of a person skilled in the art. Also, some components in one embodiment may be replaced with corresponding components in other embodiments.

[0097] REFERENCE SIGNS LIST 1: plasma processing apparatus, 2: control unit, 10: plasma processing chamber, 11: substrate support unit, 12: plasma generation unit, W: substrate, R1: recess, ER: film to be etched, L1: first layer, L2: second layer

Claims

1. (a) A step of providing a substrate including an etching target film having a recess on a substrate support portion in a chamber; (b) a step of exposing the substrate to a first processing gas containing a first halogen and hydrogen to form a first layer on the surface of the recess, wherein the first layer includes at least one of a halogenated surface and a surface to which hydrogen halide is adsorbed; and (c) a step of exposing the substrate to plasma generated from a second processing gas containing a second halogen and a Group 14 element to form a second layer containing the second halogen and the Group 14 element on the surface of the recess. A substrate processing method comprising the steps.

2. The surface of the recess includes a first region and a second region above the first region, and the thickness of the second layer formed in the first region is greater than the thickness of the second layer formed in the second region. The substrate processing method according to claim 1.

3. The first region includes the surface of the bottom of the recess, and the second region includes the surface of the side wall of the recess. The substrate processing method according to claim 2.

4. In the step (b), the temperature of the substrate support portion or the temperature of the substrate is controlled to 250 ° C. or lower. The substrate processing method according to claim 1.

5. In the step (c), a bias signal is supplied to the substrate support portion. The substrate processing method according to claim 1.

6. In the step (b), plasma is generated from the first processing gas, and no bias signal is supplied to the substrate support portion. The substrate processing method according to claim 1.

7. (d) After the step (c), further including a step of etching the etching target film. The substrate processing method according to claim 1.

8. Repeating a cycle including the step (c) and the step (d). The substrate processing method according to claim 7.

9. The first processing gas includes at least one selected from the group consisting of HF gas, HCl gas, HBr gas, and HI gas. The substrate processing method according to claim 1.

10. The second processing gas includes at least one selected from the group consisting of CF-based gases, CHF-based gases, CBr-based gases, CHBr-based gases, CCl-based gases, CHCl-based gases, CI-based gases, CHI-based gases, and SiCl-based gases. The substrate processing method according to claim 1.

11. The substrate processing method according to claim 1, wherein the film to be etched is a film containing at least one selected from the group consisting of silicon, carbon, and metal.

12. In the step (c), the substrate is exposed to a plasma having an electron density of 10 １５ / m 3 or higher, and the substrate processing method according to claim 1.

13. The substrate processing method according to claim 1, wherein the film to be etched has a plurality of the recesses having different width dimensions.

14. The substrate processing method according to claim 1, wherein the recesses of the film to be etched have a trench shape or a hole shape.

15. A substrate processing apparatus including a chamber, a substrate support portion disposed in the chamber, a plasma generation portion, and a control portion, wherein the control portion is configured to: (a) control to provide a substrate including a film to be etched having recesses on the substrate support portion in the chamber; (b) control to expose the substrate to a first processing gas including a first halogen and hydrogen to form a first layer on the surface of the recesses, the first layer including at least one of a halogenated surface and a surface to which hydrogen halide is adsorbed; and (c) control to expose the substrate to plasma generated from a second processing gas including a second halogen and a Group 14 element to form a second layer including the second halogen and the Group 14 element on the surface of the recesses.

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