Substrate processing method, substrate processing device, and substrate processing system

Abstract

In one exemplary embodiment, a substrate processing method comprises: (a) a step for providing a substrate, the substrate including a silicon-containing film and a mask that is formed on the silicon-containing film and includes an opening, the silicon-containing film being exposed at the bottom of the opening; (b) a step for forming a metal-containing film on the mask and on the silicon-containing film exposed at the bottom; (c) a step for exposing the substrate to a first plasma generated from a first processing gas that contains a halogen-containing gas to etch the metal-containing film formed on the silicon-containing film; and (d) a step for exposing the substrate to a second plasma generated from a second processing gas that contains a hydrogen halide gas to etch the silicon-containing film.

Description

Substrate processing method, substrate processing apparatus, and substrate processing system

[0001] Exemplary embodiments of this disclosure relate to substrate processing methods, substrate processing apparatuses, and substrate processing systems.

[0002] In the manufacturing of electronic devices, plasma etching is performed on substrate films. Plasma etching is applied, for example, to silicon-containing films. In plasma etching of silicon-containing films, a processing gas containing fluorocarbon gas is used. Such plasma etching is described in Patent Document 1 below.

[0003] U.S. Patent Application Publication No. 2018 / 0286707

[0004] This disclosure provides a substrate processing method, a substrate processing apparatus, and a substrate processing system that can suppress shape abnormalities in recesses.

[0005] In one exemplary embodiment, the substrate processing method includes: (a) providing a substrate, the substrate comprising a silicon-containing film and a mask formed on the silicon-containing film and including an opening, wherein the silicon-containing film is exposed at the bottom of the opening; (b) forming a metal-containing film on the mask and on the silicon-containing film exposed at the bottom; (c) etching the metal-containing film formed on the silicon-containing film by exposing the substrate to a first plasma generated from a first processing gas containing a halogen-containing gas; and (d) etching the silicon-containing film by exposing the substrate to a second plasma generated from a second processing gas containing a hydrogen halide gas.

[0006] According to one exemplary embodiment, shape abnormalities in the recess can be suppressed.

[0007] Figure 1 is a schematic diagram showing a plasma processing apparatus according to one exemplary embodiment. Figure 2 is a schematic diagram showing a plasma processing apparatus according to one exemplary embodiment. Figure 3 is a flowchart of a substrate processing method according to one exemplary embodiment. Figure 4 is a cross-sectional view of an example substrate to which the method of Figure 3 may be applied. Figure 5 is a cross-sectional view showing one step of a substrate processing method according to one exemplary embodiment. Figure 6 is a cross-sectional view showing one step of a substrate processing method according to one exemplary embodiment. Figure 7 is a cross-sectional view showing one step of a substrate processing method according to one exemplary embodiment. Figure 8 is a graph showing an example of the resistance of silicon-containing films and metal-containing films to gases containing hydrogen fluoride. Figure 9 is a cross-sectional view showing one step of a substrate processing method according to one exemplary embodiment. Figure 10 is a flowchart of a substrate processing method according to another exemplary embodiment. Figure 11 is a flowchart of a substrate processing method according to another exemplary embodiment. Figure 12 is a flowchart of a substrate processing method according to another exemplary embodiment. Figure 13 is a cross-sectional view showing one step of a substrate processing method for a substrate according to another exemplary embodiment. Figure 14 is a cross-sectional view showing one step of a substrate processing method for a substrate according to another exemplary embodiment. Figure 15 is a cross-sectional view showing one step of a substrate processing method for a substrate according to another exemplary embodiment. Figure 16 is a cross-sectional view showing one step of a substrate processing method for a substrate according to another exemplary embodiment. Figure 17 is a cross-sectional view showing one step of a substrate processing method for a substrate according to another exemplary embodiment. Figure 18 is a flowchart of a substrate processing method according to another exemplary embodiment. Figure 19 is a cross-sectional view showing one step of a substrate processing method for a substrate according to another exemplary embodiment. Figure 20 is a cross-sectional view showing one step of a substrate processing method for a substrate according to another exemplary embodiment. Figure 21 is a graph showing an example of the relationship between the number of cycles and the opening width of the recess. Figure 22 is a graph showing an example of the relationship between the number of cycles and the depth of the recess. Figure 23 is a graph showing an example of the relationship between the depth of the recess in the silicon-containing film and the opening width of the recess. Figure 24 is a graph showing an example of the relationship between the number of cycles and the film thickness of the metal-containing film at substrate support temperatures of 100°C and 200°C, respectively.Figure 25 is a graph showing an example of the relationship between the opening width and the depth of the mask opening when the supply time of the precursor gas is changed. Figure 26 is a graph showing an example of the relationship between the opening width and the depth of the mask opening when the supply time of the reaction gas is changed. Figure 27 is a schematic diagram showing a substrate processing system according to one exemplary embodiment. Figure 28 is an example of a graph showing the pattern of recesses after etching. Figure 29 is a graph showing the pattern of the mask opening and the recesses of the silicon-containing film after etching for the first, fourth, and fifth samples. Figure 30 is a graph showing the pattern of the mask opening and the recesses of the silicon-containing film after etching for the third, fourth, and fifth samples. Figure 31 is a graph showing the pattern of the mask opening and the recesses of the silicon-containing film after etching for the first, third, and sixth samples. Figure 32 is a graph showing the pattern of the mask opening and the recesses of the silicon-containing film after etching for the seventh to tenth samples.

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

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

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

[0011] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to perform the various processes described herein. The control unit 2 may be configured to control the elements of the plasma processing apparatus 1 to perform the various processes described herein. In one embodiment, part or all of the control unit 2 may be included in the plasma processing apparatus 1. The control unit 2 is implemented, for example, by a computer 2a. The control unit 2 may include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The functions realized by the processing unit 2a1 described herein may be implemented in a circuit or processing circuit, including a general-purpose processor, an application-specific processor, integrated circuits, ASICs (Application Specific Integrated Circuits), a CPU (Central Processing Unit), a conventional circuit, and / or a combination thereof, programmed to realize the described functions. The processor is considered to be a circuit or processing circuit, including transistors and other circuits. The processor may be a programmed processor that executes a program stored in the storage unit 2a2. This program may be pre-stored in the storage unit 2a2 or retrieved via a medium when needed. The acquired program is stored in the storage unit 2a2 and read from the storage unit 2a2 and executed by the processing unit 2a1. The medium may be various storage media readable by the computer 2a, or it may be a communication line connected to the communication interface 2a3. The 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 via a communication line such as a LAN (Local Area Network).In this disclosure, circuits, units, and means are hardware programmed to perform or configured to perform the functions described. Such hardware may be any hardware described in this disclosure, or any hardware known to be programmed to perform or execute the functions described. If such hardware is a processor that is considered to be a type of circuit, such circuit, means, or unit is a combination of hardware and software used to constitute such hardware and / or processor.

[0012] The following describes an example configuration of a capacitively coupled plasma processing apparatus as an example of a plasma processing apparatus 1. Figure 2 is a diagram illustrating an example configuration of a capacitively coupled plasma processing apparatus.

[0013] The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply system 30, and an exhaust system 40. The plasma processing apparatus 1 also includes a substrate support unit 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 unit 11 is located inside the plasma processing chamber 10. The shower head 13 is located above the substrate support unit 11. In one embodiment, the shower head 13 constitutes at least a portion of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the shower head 13, the side walls 10a of the plasma processing chamber 10, and the substrate support unit 11. The plasma processing chamber 10 is grounded. The shower head 13 and the substrate support unit 11 are electrically insulated from the housing of the plasma processing chamber 10.

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

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

[0016] The ring assembly 112 includes one or more annular members. In one embodiment, the one or more annular members include one or more edge rings and at least one covering ring. The edge rings are formed of a conductive or insulating material, and the covering rings are formed of an insulating material.

[0017] The substrate support section 11 may also include a temperature control 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 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 base 1110, and one or more heaters are arranged within the ceramic member 1111a of the electrostatic chuck 1111. The substrate support section 11 may also include a heat transfer gas supply section configured to supply heat transfer gas to the gap between the back surface of the substrate W and the central region 111a.

[0018] The showerhead 13 is configured to introduce at least one processing gas from the gas supply unit 20 into the plasma processing space 10s. The showerhead 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and a plurality of gas inlet ports 13c. The processing gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the plasma processing space 10s through the plurality of gas inlet ports 13c. The showerhead 13 also includes at least one upper electrode. In addition to the showerhead 13, the gas introduction unit may also include one or more side gas injectors (SGIs) attached to one or more openings formed in the side wall 10a.

[0019] The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one processing gas to the shower head 13 from a corresponding gas source 21 via a corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Furthermore, the gas supply unit 20 may include at least one flow modulation device that modulates or pulses the flow rate of at least one processing gas.

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

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

[0022] The second RF generation unit 31b is electrically connected to or coupled to at least one lower electrode and is configured to generate a bias RF signal (bias RF power). In one embodiment, the second RF generation unit 31b is electrically connected to or coupled to at least one lower electrode via at least one impedance matcher. When the first RF generation unit 31a is electrically connected to or coupled to a lower electrode, the second RF generation unit 31b may be electrically connected to or coupled to the same lower electrode, or it may be electrically connected to or coupled to a different lower electrode. 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 generation unit 31b may be configured to generate a plurality of bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to at least one lower electrode. In various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0023] The power supply system 30 may also include a power supply 32 that is electrically connected to or coupled to the plasma processing chamber 10. The power supply 32 includes a first voltage generation unit 32a and a second voltage generation unit 32b. In one embodiment, the first voltage generation unit 32a is electrically connected to or coupled to at least one lower electrode and is configured to generate a first voltage signal. The generated first voltage signal is applied to at least one lower electrode. In one embodiment, the second voltage generation unit 32b is electrically connected to or coupled to at least one upper electrode and is configured to generate a second voltage signal. The generated second voltage signal is applied to at least one upper electrode.

[0024] In various embodiments, the first and / or second voltage signals may be pulsed. In this case, the first voltage generation unit 32a and / or the second voltage generation unit 32b function as a voltage pulse generation unit configured to generate a sequence of voltage pulses. Accordingly, the sequence of voltage pulses is applied to at least one lower electrode and / or at least one upper electrode. In one embodiment, the sequence of voltage pulses has a plurality of cycles, and each cycle includes a burst of voltage pulses in a first period and a constant reference voltage in a second period. That is, in the sequence of voltage pulses, the burst of voltage pulses is repeated. The absolute value of the voltage level of the voltage pulse is greater than the absolute value of the voltage level of the reference voltage. The voltage pulse may have a rectangular, trapezoidal, triangular, or any waveform having a combination thereof, and the arbitrary waveform may change over time. The voltage pulse may have a positive polarity or a negative polarity. Also, the sequence of voltage pulses may include one or more positive-polarity voltage pulses and one or more negative-polarity voltage pulses within one cycle. Note that the first and second voltage generation units 32a and 32b may be provided in addition to the power supply 31, or the first voltage generation unit 32a may be provided in place of the second RF generation unit 31b.

[0025] The exhaust system 40 can be connected to, for example, a gas discharge 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 adjusted by the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0026] FIG. 3 is a flowchart of a substrate processing method according to one exemplary embodiment. The substrate processing method shown in FIG. 3 (hereinafter referred to as "method MT1") can be executed by the plasma processing apparatus 1 of the above embodiment. Method MT1 can be applied to the substrate W in FIG. 4.

[0027] FIG. 4 is a cross-sectional view of a substrate in an example where the method of FIG. 3 can be applied. As shown in FIG. 4, in one embodiment, the substrate W includes a silicon-containing film RE and a mask MK formed on the silicon-containing film RE and including an opening OP1. The silicon-containing film RE is an area to be etched. The substrate W may further include an underlying film UR. The silicon-containing film RE is formed on the underlying film UR.

[0028] In the example of FIG. 4, the mask MK includes one opening OP1, but the mask MK may include one or more openings OP1. That is, the mask MK may include a plurality of openings OP1. The opening OP1 may have a line pattern or a hole pattern. The opening OP1 can be defined by a bottom OP1a and sidewalls OP1b. The opening OP1 penetrates the mask MK, and at the bottom OP1a of the opening OP1, the silicon-containing film RE is exposed. In a portion of the mask MK other than the opening OP1, the surface on the opposite side of the silicon-containing film RE constitutes the upper part MKa of the mask MK.

[0029] The silicon-containing film RE may include at least one selected from the group consisting of a multilayer film, a silicon oxide film (SiO ｘ ), a silicon nitride film (SiN ｘ ), and a polysilicon film. The multilayer film may include at least two or more films selected from a silicon oxide film, a silicon nitride film, and a phosphorus-containing silicon film. Here, the phosphorus-containing silicon film is, for example, a film in which phosphorus is added as an additive element to the silicon-containing film. The phosphorus-containing silicon film may include at least one selected from the group consisting of a silicon oxide film containing phosphorus (SiOP) and a silicon nitride film containing phosphorus (SiNP). The multilayer film is, as an example, a film in which at least two or more films selected from a silicon oxide film, a silicon nitride film, and a phosphorus-containing silicon film are alternately laminated. The silicon-containing film RE may further include at least one material selected from the group consisting of silicon oxynitride (SiON) and silicon carbonitride (SiCN). x is a positive real number.

[0030] The mask MK may contain a carbon-containing film. The carbon-containing film is, for example, an amorphous carbon film, a spin-on carbon film, or a photoresist film. The mask MK may be formed by ALC (Ashing Less Coating). ALC is, for example, a coating method in which the ashing step for removing photoresist is omitted. In this case, the opening OP1 may be formed on the mask MK without the ashing step being performed.

[0031] The following describes method MT1, taking as an example the case where method MT1 is applied to the substrate W using the plasma processing apparatus 1 of the above embodiment, with reference to Figures 4 to 8. Figures 5 to 7 and 9 are cross-sectional views showing one step of a substrate processing method according to one exemplary embodiment. When the plasma processing apparatus 1 is used, method MT1 can be executed in the plasma processing apparatus 1 by the control unit 2 controlling each part of the plasma processing apparatus 1. In method MT1, as shown in Figure 2, the substrate W on the substrate support part 11 arranged in the plasma processing chamber 10 is processed. As shown in Figure 3, method MT1 may include steps ST1 to ST5. Steps ST1 to ST5 can be executed in order. Method MT1 does not have to include step ST5.

[0032] (Step ST1) In Step ST1, the substrate W shown in Figure 4 is provided onto the substrate support 11 in the plasma processing chamber 10.

[0033] (Step ST2) In step ST2, as shown in Figure 5, a metal-containing film ML is formed on the mask MK and on the silicon-containing film RE exposed at the bottom OP1a. The metal-containing film ML may be formed continuously from the upper part MKa of the mask MK through the side wall OP1b to the bottom OP1a. The mask MK may contain tin. The metal-containing film ML may contain at least one selected from the group consisting of tin, titanium, molybdenum, tantalum, gallium, hafnium, zirconium, and ruthenium. The metal-containing film ML does not have to contain a carbon-containing film or a silicon-containing film. The metal-containing film ML may contain, for example, a material that exhibits high resistance to fluorine-containing gases. High resistance in this case means that it is not easily volatile. Tin and tantalum are examples of materials that exhibit high resistance to fluorine-containing gases.

[0034] Step ST2 may be performed before recesses are formed in the silicon-containing film RE exposed at the bottom OP1a. That is, step ST2 may be performed before the silicon-containing film RE is etched. In this case, the metal-containing film ML is not formed on the recesses formed in the silicon-containing film RE.

[0035] In step ST2, the metal-containing film ML may be formed by at least one selected from the group consisting of atomic layer deposition (ALD), chemical vapor deposition (CVD), and molecular layer deposition (MLD). Atomic layer deposition is a method of forming a film in atomic layer units by alternately supplying a precursor gas and a reaction gas. Chemical vapor deposition is a method of forming a film by utilizing chemical reactions in the gas phase. Molecular layer deposition is a method of forming a film in molecular layer units by alternately supplying a precursor gas and a reaction gas.

[0036] In atomic layer deposition, a metal-containing film ML may be formed conformally on the surface of the substrate W. In this case, the metal-containing film ML may be formed such that its thickness is uniform from the upper MKa through the side wall OP1b to the bottom OP1a. Alternatively, the metal-containing film ML may be formed subconformally on the surface of the substrate W. In this case, the metal-containing film ML may be formed such that its thickness is non-uniform from the upper MKa through the side wall OP1b to the bottom OP1a. For example, the thickness of the metal-containing film ML formed on the upper MKa may be greater than the thickness of the metal-containing film ML formed on the side wall OP1b or the thickness of the metal-containing film ML formed on the bottom OP1a. The thickness of the metal-containing film ML formed on the side wall OP1b may decrease monotonically from the upper MKa towards the bottom OP1a. This disclosure describes a case in which a conformal metal-containing film ML is formed in step ST2 by atomic layer deposition.

[0037] As shown in Figure 3, step ST2 may include steps ST21 and ST22. In step ST21, a precursor layer may be formed on the mask MK and on the silicon-containing film RE at the bottom OP1a. The precursor layer may contain, for example, a tin-containing substance. In step ST21, the substrate W may be exposed to a precursor gas to form the precursor layer. The precursor gas contains a tin-containing substance, and the precursor layer may be formed from the tin-containing substance contained in the precursor gas. The tin-containing substance may include at least one selected from the group consisting of stannane compounds, oxygen-containing tin compounds, nitrogen-containing tin compounds, and tin halide compounds.

[0038] Stannane compounds include, for example, stannane, tetramethylstannane, tetraethylstannane, tributylstannane, phenyltrimethylstannane, tetravinylstannane, dimethyldichlorostannane, butyltrichlorostannane, trichlorophenylstannane, and the like. Oxygen-containing tin compounds include, for example, tributyltin methoxide, tert-butoxide tin, dibutyltin diacetate, triphenyltin acetate, tributyltin oxide, triphenyltin acetate, triphenyltin hydroxide, butylchlorotin dihydroxide, acetylacetonate tin, and the like.

[0039] Nitrogen-containing tin compounds include, for example, dimethylaminotrimethylstannane, tris(dimethylamino)tert-butylstannane, azidotrimethylstannane, tetrakis(dimethylamino)stannane, N,N'-di-tert-butyl-2,3-diamidobutane tin(II), bis(1-dimethylamino-2-methyl-2-propoxy)stannane, and the like. Halogenated tin compounds include, for example, tin chloride, tin bromide, tin iodide, dimethyltin dichloride, butyltin trichloride, phenyltin trichloride, and the like.

[0040] The precursor layer contains, for example, a tantalum-containing substance. The precursor gas contains a tantalum-containing substance, and thus, the precursor layer may be formed from the tantalum-containing substance contained in the precursor gas. The tantalum-containing substance may contain at least one selected from the group consisting of a nitrogen-containing tantalum compound, an oxygen-containing tantalum compound, and a halogenated tantalum compound.

[0041] Nitrogen-containing tantalum compounds include tris(ethylmethylamide)(tert-butylimide)tantalum(V) (TBTEMTa: C １３ H ３３ N ４ Ta), tris(diethylamide)(tert-butylimide)tantalum ((CH ３ ) ３ CNTa(N(C ２ H ５ ) ２ ) ３ ), tris(diethylamide)(ethylimide)tantalum(V) ([(C２ H ５ ) ２ N] ３ Ta(C) ２ H ５ N)), Pentaquis(dimethylamide)tantalum(V)(Ta(N(CH) ３ ) ２ ) ５ ) etc.

[0042] Oxygen-containing tantalum compounds include, for example, tantalum (V) pentaethoxide (Ta(OC) ２ H ５ ) ５ Examples of tantalum halogenated compounds include tantalum fluoride, tantalum chloride, tantalum bromide, and tantalum iodide.

[0043] In step ST22, the precursor layer may be exposed to a reaction gas to form a metal-containing film ML from the precursor layer. The reaction gas includes, for example, at least one selected from the group consisting of inorganic compounds, sulfur-containing inorganic compounds, halogen compounds, carbon-containing substances, silicon-containing substances, and tin-containing substances. The inorganic compound is H ２ O, H ２ O ２ , O ２ , O ３ No, no ２ , N ２ O ４ It may also contain at least one selected from the group consisting of , and nitrogen. In step ST22, a metal-containing film ML may be formed by oxidizing, nitriding, sulfiding, reducing, or halogenating the precursor layer using a reaction gas.

[0044] Steps ST21 and ST22 can be performed within the plasma processing chamber 10. In step ST21, plasma may be generated from a precursor gas and a precursor layer may be formed by plasma chemical species of the precursor gas. Plasma chemical species are, for example, ions, radicals, electrons, etc., present in the plasma generated from the gas. Alternatively, in step ST21, the precursor layer may be formed without the generation of plasma from the precursor gas. Similarly, in step ST22, the metal-containing film ML may be formed by the generation of plasma from the reaction gas, or the metal-containing film ML may be formed without the generation of plasma from the reaction gas.

[0045] The temperature of the substrate support portion 11 in step ST2 may be 20°C or higher, 50°C or higher, or 100°C or higher. The temperature of the substrate support portion 11 in step ST2 may be higher than the temperature of the substrate support portion 11 in step ST3, which will be described later. The temperature of the substrate support portion 11 in step ST21 may be the same as or different from the temperature of the substrate support portion 11 in step ST22.

[0046] (Step ST3) In step ST3, as shown in Figure 6, the substrate W is exposed to a first plasma generated from a first processing gas to etch the metal-containing film ML formed on the silicon-containing film RE. The first processing gas contains a halogen-containing gas. The halogen-containing gas may also contain hydrogen halide gas. The hydrogen halide gas may also contain a fluorine-containing gas. The hydrogen halide gas may also contain hydrogen fluoride gas. ｘ ), and phosphorus fluoride gas (PF ｘ The first treatment gas may further include at least one selected from the group consisting of ) . If the hydrogen halide gas includes hydrogen fluoride gas, the metal-containing film ML may be etched by the hydrogen fluoride chemical species. The first treatment gas may further include at least one selected from the group consisting of carbon-containing gas, phosphorus-containing gas, halogen-containing gas, and metal-containing gas.

[0047] The halogen-containing gas may also contain a chlorine-containing gas. The chlorine-containing gas may also contain chlorine gas. When the halogen-containing gas contains a chlorine-containing gas, the metal-containing film ML may be etched by the chlorine chemical species.

[0048] If the metal-containing film ML contains tantalum, the first processing gas may also contain hydrogen fluoride gas and phosphorus-containing gas. In this case, the metal-containing film ML can be etched by hydrogen fluoride species and phosphorus species.

[0049] In step ST3, a first processing gas may be continuously supplied into the plasma processing chamber 10 containing the substrate W. For example, the gas supply unit 20 supplies the first processing gas at a constant flow rate throughout step ST3. Alternatively, for example, the gas supply unit 20 supplies the first processing gas as a pulse wave that repeatedly switches on and off at a constant period throughout step ST3. In step ST3, a first plasma may be continuously generated. For example, the first RF generation unit 31a generates a source RF signal for generating plasma as a continuous wave throughout step ST3. Alternatively, for example, the first RF generation unit 31a generates a source RF signal as a pulse wave that repeatedly switches on and off at a constant period throughout step ST3. Similarly, in step ST3, a bias RF signal may be continuously supplied to the substrate support unit 11. For example, the second RF generation unit 31b generates a bias RF signal as a continuous wave throughout step ST3. Alternatively, for example, the second RF generation unit 31b generates a bias RF signal as a pulse wave that constantly switches on and off at a constant period during process ST3.

[0050] In step ST3, as described above, anisotropic etching may be promoted by continuously supplying a first processing gas, generating a first plasma, and supplying a bias RF signal. In this case, as shown in Figure 6, etching perpendicular to the metal-containing film ML on the silicon-containing film RE exposed at the bottom OP1a proceeds more easily than etching horizontally to the metal-containing film ML formed on the side wall OP1b. This allows for the selective removal of the metal-containing film ML on the silicon-containing film RE exposed at the bottom OP1a. Etching may also proceed to the metal-containing film ML formed on the upper MKa. In this case, as shown in Figure 6, the thickness of the metal-containing film ML formed on the upper MKa may be thinner compared to before etching shown in Figure 5.

[0051] The temperature of the substrate support portion 11 in step ST3 may be 0°C or lower. The temperature of the substrate support portion 11 in step ST3 may be 30°C or lower, or 50°C or lower. The temperature of the substrate support portion 11 in step ST3 may be lower than the temperature of the substrate support portion 11 in step ST2.

[0052] Step ST3 may be performed in the plasma processing chamber 10. That is, the chamber in which step ST3 is performed may be the same as the chamber in which step ST2 is performed. In this case, step ST3 may be performed simultaneously with step ST22. The first processing gas used in step ST3 may be the same as the reaction gas used in step ST22. In step ST3, for example, while step ST22 is being performed, the silicon-containing film RE is etched by chemical species from the first plasma. By performing steps ST22 and ST3 simultaneously, a metal-containing film ML may be formed from the precursor layer, and at the same time, the silicon-containing film RE may be etched.

[0053] (Step ST4) In step ST4, as shown in Figure 7, the substrate W is exposed to a second plasma generated from the second processing gas to etch the silicon-containing film RE. The second processing gas contains a second hydrogen halide gas. The second hydrogen halide gas may be the same as the first hydrogen halide gas. The second hydrogen halide gas may also contain hydrogen fluoride gas. The second hydrogen halide gas may contain at least one selected from the group consisting of hydrogen fluoride gas, carbon fluoride gas, and phosphorus fluoride gas. The second processing gas may further contain at least one selected from the group consisting of carbon-containing gas, phosphorus-containing gas, halogen-containing gas, and metal-containing gas.

[0054] In step ST4, the silicon-containing film RE is etched to form a recess OP2 in the silicon-containing film RE. The recess OP2 communicates with the opening OP1. The recess OP2 can be defined by a bottom OP2a and a side wall OP2b. The recess OP2 may penetrate the silicon-containing film RE. The base film UR may be exposed at the bottom OP2a of the recess OP2.

[0055] If the metal-containing film ML contains tantalum, the second processing gas may also contain hydrogen fluoride gas and phosphorus-containing gas. In this case, the silicon-containing film RE can be etched by hydrogen fluoride species and phosphorus species.

[0056] In step ST4, a second processing gas may be continuously supplied into the plasma processing chamber 10 containing the substrate W. For example, the gas supply unit 20 supplies the second processing gas at a constant flow rate throughout step ST4. Alternatively, for example, the gas supply unit 20 supplies the second processing gas as a pulse wave that repeatedly switches on and off at a constant period throughout step ST4. In step ST4, a second plasma may be continuously generated. For example, the first RF generation unit 31a generates a source RF signal for generating plasma as a continuous wave throughout step ST4. Alternatively, for example, the first RF generation unit 31a generates a source RF signal as a pulse wave that repeatedly switches on and off at a constant period throughout step ST4. Similarly, in step ST4, a bias RF signal may be continuously supplied to the substrate support unit 11. For example, the second RF generation unit 31b generates a bias RF signal as a continuous wave throughout step ST4. Alternatively, for example, the second RF generation unit 31b generates a bias RF signal as a pulse wave that constantly switches on and off at a constant period during process ST4.

[0057] In step ST4, as described above, anisotropic etching may be promoted by continuously supplying a second processing gas, generating a second plasma, and supplying a bias RF signal. In this case, as shown in Figure 7, etching can proceed while suppressing horizontal etching of the side wall OP2b of the recess OP2 and the side wall OP1b of the opening OP1.

[0058] Furthermore, as mentioned above, when the metal-containing film ML contains a tin-containing substance, it exhibits high resistance to fluorine-containing gases, for example. In contrast, the silicon-containing film RE has lower resistance to fluorine-containing gases compared to the metal-containing film ML. Figure 8 is a graph showing an example of the resistance of silicon-containing films and metal-containing films to gases containing hydrogen fluoride. In the example in Figure 8, sample A, in which a line-and-space pattern of silicon oxide film was formed on a silicon substrate, and sample B, in which a tin oxide film was further formed on the line-and-space pattern of the oxide film, were each subjected to carbon tetrafluoroethylene (CF4). ４Figure 8 shows the results of etching after exposure to gas. In the example in Figure 8, the etching depth is shown on the top surface of the line portion, the side surface of the line portion, and the space portion (between adjacent line portions) in the line and space patterns of sample A and sample B. As shown in Figure 8, the etching depth of sample A is approximately 10 times that of sample B on the top surface and in the space portion. From this, it can be said that the tin oxide film is less volatile to fluorine-containing gas and has high resistance compared to the silicon oxide film. As a result, as shown in Figure 7, in step ST4, the selectivity ratio of the silicon-containing film RE to the metal-containing film ML is increased, allowing etching to proceed while horizontal etching of the side wall OP1b of the opening OP1 is suppressed.

[0059] Even when the metal-containing film ML contains tantalum-containing material, it exhibits high resistance to, for example, fluorine-containing gases. In addition, when the first and second processing gases each contain hydrogen fluoride gas and phosphorus-containing gas, the reactants derived from hydrogen fluoride are replaced by reactants derived from phosphorus, which can reduce the removal rate of tantalum. As a result, in step ST4, the selectivity ratio of the silicon-containing film RE to the metal-containing film ML is increased, allowing etching to proceed while suppressing horizontal etching of the side wall OP1b of the opening OP1.

[0060] The temperature of the substrate support portion 11 in step ST4 may be 0°C or lower. The temperature of the substrate support portion 11 in step ST4 may be 30°C or lower, or 50°C or lower. The temperature of the substrate support portion 11 in step ST4 may be the same as the temperature of the substrate support portion 11 in step ST3.

[0061] (Step ST5) In step ST5, the mask MK is removed as shown in Figure 9. In step ST5, the mask MK is removed by ashing, for example. As an example, the substrate W is exposed to hydrogen plasma generated from hydrogen gas to etch the mask MK.

[0062] According to the method MT1 described above, by forming a metal-containing film ML on the mask MK in step ST2, the metal-containing film ML can function as a protective film that protects the side wall OP1b of the opening OP1 of the mask MK. As a result, etching of the side wall OP1b of the opening OP1 is suppressed in steps ST3 and ST4, and etching of the side wall OP2b of the recess OP2 formed in the silicon-containing film RE is also suppressed. Therefore, shape abnormalities of the opening OP1 and the recess OP2 can be suppressed.

[0063] The metal-containing film ML may also contain tin. In this case, since the tin-containing film has higher etching resistance compared to the carbon-containing film and the silicon-containing film, it becomes easier to further suppress shape abnormalities in the recessed area OP2.

[0064] Step ST2 may include steps ST21 and ST22. In this case, by reacting a precursor layer containing a tin-containing substance with a reaction gas in step ST22, a metal-containing film ML containing a tin-containing substance and having high etching resistance can be formed.

[0065] The first hydrogen halide gas contained in the first processing gas may be the same gas as the second hydrogen halide gas contained in the second processing gas. In this case, the etching process can be simplified.

[0066] The first hydrogen halogen gas and the second hydrogen halogen gas may also include hydrogen fluoride gas. If the metal-containing film ML contains tin, since tin is less volatile to fluorine, etching of the side wall OP1b of the opening OP1 is further suppressed in steps ST3 and ST4.

[0067] Although various exemplary embodiments have been described above, the invention is not limited to the exemplary embodiments described above, and various additions, omissions, substitutions, and modifications may be made. Furthermore, it is possible to combine elements from different embodiments to form other embodiments.

[0068] In the plasma processing apparatus 1, instead of method MT1, a substrate processing method (hereinafter referred to as "method MT2") as shown in Figure 10 may be performed. Method MT2 differs from method MT1 in that it includes step ST1A instead of steps ST1 and ST2, and is otherwise the same as method MT1. In step ST1A, the substrate W shown in Figure 5 is provided on the substrate support 11 in the plasma processing chamber 10. That is, the substrate W provided in step ST1A includes a silicon-containing film RE and a mask MK formed on the silicon-containing film RE and including an opening OP1 which includes a bottom OP1a where the silicon-containing film RE is exposed. In addition, the substrate W further includes a metal-containing film ML formed on the mask MK and on the silicon-containing film RE exposed at the bottom OP1a. In this case, the plasma processing apparatus 1 may perform etching of the metal-containing film ML in step ST3, etching of the silicon-containing film RE in step ST4, and removal of the mask MK in step ST5. The first processing gas used in step ST3 includes a halogen-containing gas. The halogen-containing gas may also include hydrogen halide gas. The halogen-containing gas may also include a chlorine-containing gas. The chlorine-containing gas may also include chlorine gas. In method MT2, since a substrate W is provided on which a metal-containing film ML is formed on the mask MK in step ST1A, the metal-containing film ML can function as a protective film that protects the side wall OP1b of the opening OP1 of the mask MK. Therefore, shape abnormalities of the opening OP1 and the recess OP2 can be suppressed. In method MT2, the metal-containing film ML may be formed on the silicon-containing film RE exposed on the mask MK and at the bottom OP1a after the opening OP1 is formed on the mask MK. In this case, the steps of forming the opening OP1 on the mask MK and forming the metal-containing film ML on the silicon-containing film RE exposed on the mask MK and at the bottom OP1a may be performed in a plasma processing apparatus different from the plasma processing apparatus 1, for example, an inductively coupled plasma processing apparatus.

[0069] In the plasma processing apparatus 1, instead of method MT1, a substrate processing method (hereinafter referred to as "method MT3") as shown in Figure 11 may be performed. Method MT3 differs from method MT1 in that it does not include step ST3, and is otherwise the same as method MT1. In method MT3, in step ST21, it is not necessary to form a precursor layer on the silicon-containing film RE at the bottom OP1a. In this case, in step ST22, it is not necessary to form a metal-containing film ML on the silicon-containing film RE at the bottom OP1a. In method MT3, in step ST2, the metal-containing film ML may be formed only on the mask MK. Therefore, since it is not necessary to etch the metal-containing film ML formed on the silicon-containing film RE in step ST3, step ST4 may be performed after the completion of step ST2. In step ST4 of method MT3, the substrate W is exposed to plasma generated from the processing gas to etch the silicon-containing film RE. The processing gas contains hydrogen halide gas. In method MT3, by forming a metal-containing film ML on the mask MK in step ST2, the metal-containing film ML can function as a protective film that protects the side wall OP1b of the opening OP1 of the mask MK. Therefore, shape abnormalities of the opening OP1 and the recess OP2 can be suppressed. In method MT3, the metal-containing film ML may be formed on the silicon-containing film RE exposed on the mask MK and at the bottom OP1a after the opening OP1 has been formed on the mask MK. In this case, the steps of forming the opening OP1 on the mask MK and forming the metal-containing film ML on the silicon-containing film RE exposed on the mask MK and at the bottom OP1a may be performed in a plasma processing apparatus different from the plasma processing apparatus 1, for example, an inductively coupled plasma processing apparatus.

[0070] In the plasma processing apparatus 1, instead of method MT2, a substrate processing method (hereinafter referred to as "method MT4") as shown in Figure 12 may be performed. Method MT4 differs from method MT2 in that it does not include step ST3, but is otherwise the same as method MT2. The substrate W provided in step ST1A of method MT4 includes a metal-containing film ML formed on the mask MK, but does not necessarily include a metal-containing film ML formed on the silicon-containing film RE exposed at the bottom OP1a. Therefore, since it is not necessary to etch the metal-containing film ML formed on the silicon-containing film RE in step ST3, step ST4 may be performed after the completion of step ST1A. In step ST4 of method MT4, the substrate W is exposed to plasma generated from a processing gas to etch the silicon-containing film RE. The processing gas includes hydrogen halide gas. In method MT4, since a substrate W is provided on which a metal-containing film ML is formed on the mask MK in step ST1A, the metal-containing film ML can function as a protective film that protects the side wall OP1b of the opening OP1 of the mask MK. Therefore, shape abnormalities of the opening OP1 and the recess OP2 can be suppressed.

[0071] In step ST2 of methods MT1 and MT3 described above, the metal-containing film ML may be formed conformally on the surface of the substrate W, or it may be formed subconformally, as previously stated. When the metal-containing film ML is formed subconformally, the thickness of the metal-containing film ML may gradually decrease from the upper part MKa through the side wall OP1b to the bottom part OP1a. Alternatively, in step ST2, the metal-containing film ML may be formed such that its thickness gradually increases from the upper part MKa through the side wall OP1b to the bottom part OP1a. In step ST2, the method of forming the metal-containing film ML may be selected according to the shape of the opening OP1 of the mask MK. Several formation methods will be described below with reference to Figures 13 to 17. Figures 13 to 17 are cross-sectional views showing one step of a substrate processing method for a substrate according to another exemplary embodiment.

[0072] Figure 13(a) shows step ST1 of method MT3 applied to substrate W2, and Figure 13(b) shows step ST2 of method MT3 applied to substrate W2. Substrate W2 differs from substrate W in that it includes an opening OP3 instead of an opening OP1. The opening OP3 has an opening dimension (first opening dimension) WD1 at a position (first position) PS1 in the thickness direction DR of substrate W2. The opening OP3 has an opening dimension (second opening dimension) WD2 that is smaller than the opening dimension WD1 at a position (second position) PS2 different from position PS1. As shown in Figure 13(a), the opening OP3 may have a tapered shape that narrows from the top MKa through the side wall OP3b to the bottom OP3a. Position PS2 may be located closer to the bottom OP3a than position PS1.

[0073] Step ST2 may include the step of forming the metal-containing film ML such that the opening OP3 has an opening dimension (third opening dimension) WD3 at position PS1 when the metal-containing film ML is formed on the mask MK. The opening dimension WD3 may be smaller than the opening dimension WD1 and less than or equal to the opening dimension WD2. In the example of Figure 13(b), the metal-containing film ML is formed subconformally. As a result, for example, the opening dimension of the opening OP3 is constant at the opening dimension WD3 in the thickness direction DR from the upper part MKa through the side wall OP3b to the bottom part OP3a. In the example of Figure 13(b), the opening dimension WD3 is the same as the opening dimension WD2. In step ST2, it is not necessary to form the metal-containing film ML on the silicon-containing film RE at the bottom part OP3a.

[0074] Figure 14(a) shows step ST1 of method MT1 applied to substrate W3, and Figure 14(b) shows step ST2 of method MT1 applied to substrate W3. Substrate W3 differs from substrate W in that it includes an opening OP4 instead of an opening OP1. The opening OP4 has an opening dimension (first opening dimension) WD1 at a position (first position) PS1 in the thickness direction DR of substrate W3. The opening OP4 has an opening dimension (second opening dimension) WD2 that is smaller than the opening dimension WD1 at a position (second position) PS2 different from position PS1. As shown in Figure 14(a), the opening OP4 may have a bulging shape at the bottom. Specifically, the opening dimension of the opening OP4 may be constant at the opening dimension WD2 in the thickness direction DR from the upper part MKa to partway down the side wall OP4b. Furthermore, the opening dimensions of the opening OP4 may gradually widen from the middle of the side wall OP4b to the bottom OP4a, reaching the opening dimension WD1. After reaching the opening dimension WD1, the opening dimensions of the opening OP4 may gradually narrow towards the bottom OP4a. Position PS2 may be located closer to the upper MKa than position PS1.

[0075] Step ST2 may include the step of forming the metal-containing film ML such that the opening OP4 has an opening dimension (third opening dimension) WD3 at position PS1 when the metal-containing film ML is formed on the mask MK. The opening dimension WD3 may be smaller than the opening dimension WD1 and less than or equal to the opening dimension WD2. In the example of Figure 14(b), the metal-containing film ML is formed such that its thickness gradually increases from the upper part MKa through the side wall OP4b to the bottom part OP4a. As a result, for example, the opening dimension of the opening OP4 is constant at the opening dimension WD3 in the thickness direction DR from the upper part MKa through the side wall OP4b to the bottom part OP4a. In the example of Figure 14(b), the opening dimension WD3 is the same as the opening dimension WD2. In step ST2, the metal-containing film ML may be formed on the silicon-containing film RE at the bottom part OP4a.

[0076] Figure 15(a) shows step ST1 of method MT3 for substrate W4, and Figure 15(b) shows step ST2 of method MT3 for substrate W4. Substrate W4 differs from substrate W in that it includes an opening OP5 instead of an opening OP1. The opening OP5 has an opening dimension (first opening dimension) WD1. From the upper part MKa through the side wall OP5b to the bottom part OP5a, the opening dimension of the opening OP5 is constant at the opening dimension WD1 in the thickness direction DR.

[0077] Step ST2 may include the step of forming the metal-containing film ML such that the opening OP5 has an opening dimension (second opening dimension) WD2 when the metal-containing film ML is formed on the mask MK. The opening dimension WD2 may be smaller than the opening dimension WD1. In the example of Figure 15(b), the metal-containing film ML is formed conformally. As a result, for example, the opening dimension of the opening OP5 is constant at the opening dimension WD2 in the thickness direction DR from the upper part MKa through the side wall OP5b to the bottom part OP5a. In step ST2, it is not necessary to form the metal-containing film ML on the silicon-containing film RE at the bottom part OP5a.

[0078] Figure 16(a) shows step ST1 of method MT3 for substrate W5, and Figure 16(b) shows step ST2 of method MT3 for substrate W5. Substrate W5 differs from substrate W in that it includes an opening OP6 instead of an opening OP1. The opening OP6 has an opening dimension (first opening dimension) WD1 at a position (first position) PS1 in the thickness direction DR of substrate W5. The opening OP6 has an opening dimension (second opening dimension) WD2 that is smaller than the opening dimension WD1 at a position (second position) PS2 different from position PS1. As shown in Figure 16(a), the opening OP6 may have a tapered shape that narrows from the top MKa through the side wall OP6b to the bottom OP6a. Position PS2 may be located closer to the bottom OP6a than position PS1.

[0079] Step ST2 may include a step of uniformly forming a metal-containing film ML on the side wall OP6b. Step ST2 may also include a step of forming the metal-containing film ML such that the opening OP6 has opening dimensions WD3 and WD4 when the metal-containing film ML is formed on the mask MK. Opening dimension WD3 may be smaller than opening dimension WD1 and larger than opening dimension WD4. Opening dimension WD4 may be smaller than opening dimension WD2. In the example of Figure 16(b), the metal-containing film ML is formed conformally. As a result, for example, the opening OP6 may have a tapered shape that narrows from the upper part MKa through the side wall OP6b to the bottom part OP6a. In step ST2, it is not necessary to form the metal-containing film ML on the silicon-containing film RE at the bottom part OP6a.

[0080] Figure 17(a) shows step ST1 of method MT3 for substrate W6, and Figure 17(b) shows step ST2 of method MT3 for substrate W6. Substrate W6 differs from substrate W in that it includes an opening OP7 instead of an opening OP1. The opening OP7 has an opening dimension (first opening dimension) WD1. The opening dimension of the opening OP7 is constant at the opening dimension WD1 in the thickness direction DR from the upper part MKa through the side wall OP7b to the bottom part OP7a.

[0081] Step ST2 may include the step of forming the metal-containing film ML such that the opening OP7 has an opening dimension (second opening dimension) WD2 and an opening dimension (third opening dimension) WD3 when the metal-containing film ML is formed on the mask MK. The opening dimension WD2 is the opening dimension at position (first position) PS1 in the thickness direction DR. The opening dimension WD3 is the opening dimension at position (second position) PS2 which is closer to the bottom OP7a than position PS1. The opening dimension WD3 may be smaller than the opening dimensions WD1 and WD2. In the example of Figure 17(b), the metal-containing film ML is formed such that its thickness gradually increases from the upper part MKa through the side wall OP7b to the bottom OP7a. As a result, for example, the opening OP7 may have a tapered shape that narrows from the upper part MKa through the side wall OP7b to the bottom OP7a. In step ST2, it is not necessary to form the metal-containing film ML on the silicon-containing film RE at the bottom OP7a.

[0082] The thickness of the metal-containing film ML may be adjusted. For example, method MT5, as shown in Figure 18, may be used to adjust the thickness of the metal-containing film ML. Method MT5 differs from method MT1 in that it includes step ST6 between steps ST2 and ST3. Step ST6 is a step in which steps ST21 and ST22 are repeated for a number of cycles N. The number of cycles N is an integer of 1 or more. By performing steps ST21 and ST22 for one cycle, the metal-containing film ML may be formed as a single atomic layer. Step ST6 is performed as an atomic layer deposition method, and after step ST6, a layer with a thickness corresponding to the number of cycles N may be deposited on the silicon-containing film RE. The magnitude of the number of cycles N may be proportional to the thickness of the metal-containing film ML.

[0083] In step ST6, the thickness of the metal-containing film ML may be adjusted according to the opening width of the mask MK. For example, a conformal metal-containing film ML is formed on the substrate W3 shown in Figure 19(a), extending from the upper part MKa through the side wall OP4b to the bottom part OP4a. The substrate W3 may be the same substrate as the substrate W3 shown in Figure 14(a). As a result, as shown in Figure 19(b), a metal-containing film ML with a uniform thickness may be formed from the upper part MKa through the side wall OP4b to the bottom part OP4a. Similarly, a conformal metal-containing film ML is formed on the substrate W2 shown in Figure 20(a), extending from the upper part MKa through the side wall OP3b to the bottom part OP3a. The substrate W2 may be the same substrate as the substrate W2 shown in Figure 13(a). As a result, as shown in Figure 20(b), a metal-containing film ML with a uniform thickness may be formed from the upper part MKa through the side wall OP3b to the bottom part OP3a.

[0084] The opening dimension WD1 in substrate W3 shown in Figure 19(a) may be wider than the opening dimension WD1 in substrate W2 shown in Figure 20(a). In this case, the number of cycles N for substrate W3 in step ST6 may be greater than the number of cycles N for substrate W2. As a result, the thickness of the metal-containing film ML formed in the opening OP4 of substrate W3 shown in Figure 19(b) may be thicker than the thickness of the metal-containing film ML formed in the opening OP3 of substrate W2 shown in Figure 20(b).

[0085] In step ST6, the number of cycles N can be adjusted to control the shape of the recess OP2 in the silicon-containing film RE formed after step ST4. Figure 21 is a graph showing an example of the relationship between the number of cycles N in step ST6 and the opening width of the recess OP2 in substrates W2 and W3, respectively. The opening width of the recess OP2 referred to here is, for example, the opening width near the boundary between the recess OP2 and the mask MK. In both substrates W3 and W2, the opening width of the recess OP2 decreases as the number of cycles N increases, that is, as the thickness of the metal-containing film ML increases. This is presumed to be because the function as a protective film is enhanced as the thickness of the metal-containing film ML formed on the side wall OP4b of the opening OP4 and the side wall OP3b of the opening OP3 increases.

[0086] Furthermore, when compared at the same number of cycles N, the opening width of the recess OP2 in substrate W3, which has a wider opening dimension WD1, tends to be larger than the opening width of the recess OP2 in substrate W2, which has a narrower opening dimension WD1. For this reason, in order to obtain the same opening width B1 in substrates W3 and W2, the number of cycles N2 for substrate W3 is greater than the number of cycles N1 for substrate W2. Thus, even when the opening dimensions WD1 are different, as in substrates W2 and W3, the opening width of the recess OP2 in the silicon-containing film RE can be adjusted to be approximately the same by adjusting the number of cycles N in process ST6.

[0087] In step ST6, the number of cycles N can be adjusted to control the depth of the recess OP2 in the silicon-containing film RE formed after step ST4. Figure 22 is a graph showing an example of the relationship between the number of cycles N in step ST6 and the depth of the recess OP2 in substrates W2 and W3, respectively. In both substrates W3 and W2, the greater the number of cycles N, that is, the thicker the metal-containing film ML becomes, the shallower the depth of the recess OP2 becomes. This is presumed to be because the etching rate decreases as the thickness of the metal-containing film ML formed on the bottom OP4a of the opening OP4 and the bottom OP3a of the opening OP3 increases.

[0088] Furthermore, when comparing with the same number of cycles N, the depth of the recess OP2 in substrate W3, which has a wider aperture dimension WD1, tends to be deeper than the depth of the recess OP2 in substrate W2, which has a narrower aperture dimension WD1. For this reason, in order to obtain the same depth D1 in substrates W3 and W2, the number of cycles N2 for substrate W3 is greater than the number of cycles N1 for substrate W2. Thus, even when the aperture dimensions WD1 are different, as in substrates W2 and W3, the depth of the recess OP2 in the silicon-containing film RE can be adjusted to the same extent by adjusting the number of cycles N in process ST6.

[0089] Figure 23 is a graph showing an example of the relationship between the depth of the recess OP2 in the silicon-containing film RE and the opening width of the recess OP2 in substrates W2 and W3, respectively. The horizontal axis of Figure 23 represents the depth of the recess OP2, as shown on the vertical axis of Figure 22, and the vertical axis of Figure 23 represents the opening width of the recess OP2, as shown on the vertical axis of Figure 21. In both substrates W3 and W2, the opening width of the recess OP2 increases as the depth of the recess OP2 increases. The rate of change of the opening width with respect to depth in substrate W3 is smaller than the rate of change of the opening width with respect to depth in substrate W2. For example, at the intersection point A1 of the straight line representing the characteristics of substrate W3 and the straight line representing the characteristics of substrate W2, the opening width and depth of the recess OP2 in substrates W2 and W3 are the same. Therefore, even when the aperture dimensions WD1 are different, as in the case of substrates W2 and W3, the depth and aperture width of the recess OP2 in the silicon-containing film RE can be adjusted to the same extent by adjusting the number of cycles N in process ST6.

[0090] In steps ST2 and ST6, the thickness of the metal-containing film ML may be adjusted by the temperature of the substrate support 11. Figure 24 is a graph showing an example of the relationship between the number of cycles N and the thickness of the metal-containing film ML at temperatures of 100°C and 200°C, respectively. For example, the rate of change of film thickness with respect to the number of cycles N when the temperature of the substrate support 11 is 200°C is greater than the rate of change of film thickness with respect to the number of cycles N when the temperature of the substrate support 11 is 100°C. This is assumed to be because the growth rate of film thickness per cycle improves at higher temperatures of the substrate support 11. As an example, by increasing the temperature of the substrate support 11, the desired film thickness can be achieved with fewer cycles N.

[0091] When the metal-containing film ML is formed subconformally, the shape of the metal-containing film ML may be adjusted. For example, the shape of the metal-containing film ML may be adjusted by the supply time of the precursor gas in step ST21. Figure 25 is a graph showing an example of the relationship between the opening width of the opening OP1 of the mask MK and the depth of the opening OP1 of the mask MK when the supply time of the precursor gas is changed. The supply times S1, S2, and S3 may increase in this order. For example, at supply time S2, the metal-containing film ML is formed above (towards the opening end) of the side wall OP1b of the opening OP1, and the opening width of the opening OP1 is smaller compared to before formation S0. On the other hand, for example, below (towards the silicon-containing film RE) of the side wall OP1b, the opening width is not smaller than before the formation of the metal-containing film ML S0. In contrast, at supply time S3, the metal-containing film ML is also formed below the side wall OP1b, and the opening width of the opening OP1 is smaller. During supply time S3, the metal-containing film ML may be formed thickly from the top to the bottom of the side wall OP1b.

[0092] During supply time S2, for example, because the supply time is shorter than during supply time S3, the precursor gas does not easily reach deep into the opening OP1 during process ST21, and a thicker precursor layer can be formed on the upper side of the side wall OP1b. As a result, a thicker metal-containing film ML can be formed on the upper side of the side wall OP1b.

[0093] When the metal-containing film ML is formed subconformally, the shape of the metal-containing film ML may be adjusted by the supply time of the reaction gas in step ST22. Figure 26 is a graph showing an example of the relationship between the opening width of the opening OP1 of the mask MK and the depth of the opening OP1 of the mask MK when the supply time of the reaction gas is changed. The supply times S4, S5, and S6 may increase in this order. The supply time S6 may be shorter than the supply time S3 in Figure 25. For example, at supply time S4, the metal-containing film ML is formed on the upper side (opening end side) of the side wall OP1b of the opening OP1, and the opening width of the opening OP1 is smaller compared to before formation S0. On the other hand, for example, on the lower side (silicon-containing film RE side) of the side wall OP1b, the opening width does not change from before the formation of the metal-containing film ML S0. In contrast, during supply times S5 and S6, the metal-containing film ML is formed even in the lower part of the side wall OP1b, and the opening width of the opening OP1 is reduced. During supply times S5 and S6, the metal-containing film ML may be formed thicker from the top to the bottom of the side wall OP1b.

[0094] In supply time S4, for example, because the supply time is shorter compared to supply times S5 and S6, the reaction gas is less likely to reach deep into the opening OP1 in process ST22, and a thicker metal-containing film ML can be formed on the upper part of the side wall OP1b.

[0095] In method MT1, the chamber in which step ST3 is performed may be different from the chamber in which step ST2 is performed. Method MT1 may be performed using a substrate processing system that separately includes a film deposition apparatus for performing step ST2 and a plasma processing apparatus for performing steps ST3 and ST4. Figure 27 shows a substrate processing system according to one exemplary embodiment. The substrate processing system PS shown in Figure 27 may be used to perform method MT1.

[0096] The substrate processing system PS comprises stages SG1 to SG4, containers CN1 to CN4, a loader module LM, an aligner AN, load lock modules LL1 and LL2, process modules PM1 to PM6, a transport module TF, and a control unit 2A. The number of stages, containers, and load lock modules in the substrate processing system PS can be one or more arbitrary numbers. The number of process modules in the substrate processing system PS can be two or more arbitrary numbers.

[0097] The bases SG1 to SG4 are arranged along one edge of the loader module LM. The containers CN1 to CN4 are each mounted on the bases SG1 to SG4. Each of the containers CN1 to CN4 is a container referred to, for example, as a FOUP (Front Opening Unified Pod). Each of the containers CN1 to CN4 is configured to house the substrate W inside.

[0098] The loader module LM has a chamber. The pressure inside the chamber of the loader module LM is set to atmospheric pressure. The loader module LM has a transport device TU1. The transport device TU1 is, for example, an articulated robot and is controlled by the control unit 2A. The transport device TU1 is configured to transport the substrate W through the chamber of the loader module LM. The transport device TU1 can transport the substrate W between each of the containers CN1 to CN4 and the aligner AN, between the aligner AN and each of the load lock modules LL1 to LL2, and between each of the load lock modules LL1 to LL2 and each of the containers CN1 to CN4. The aligner AN is connected to the loader module LM. The aligner AN is configured to adjust (calibrate) the position of the substrate W.

[0099] Load lock module LL1 and load lock module LL2 are each located between loader module LM and transport module TF. Load lock module LL1 and load lock module LL2 each provide a pre-pressure chamber.

[0100] The transport module TF is connected to each of the load lock modules LL1 and LL2 via gate valves. The transport module TF has a depressurized transport chamber TC. The transport module TF has a transport device TU2. The transport device TU2 is, for example, an articulated robot and is controlled by the control unit 2A. The transport device TU2 is configured to transport the substrate W through the transport chamber TC. The transport device TU2 can transport the substrate W between each of the load lock modules LL1 to LL2 and each of the process modules PM1 to PM6, and between any two process modules among the process modules PM1 to PM6.

[0101] Each of the process modules PM1 to PM6 is a processing apparatus configured to perform a dedicated substrate processing. One of the process modules PM1 to PM6 is a film deposition apparatus. This film deposition apparatus is used to form a metal-containing film ML in step ST2. This film deposition apparatus may include a first chamber and a first substrate support for supporting the substrate W within the first chamber. The control unit 2A is configured to control the film deposition apparatus so that the metal-containing film ML is formed on the mask MK and on the silicon-containing film RE exposed at the bottom OP1a in the first chamber. When plasma is generated in step ST2, this film deposition apparatus is a plasma processing apparatus such as the plasma processing apparatus 1 or another plasma processing apparatus. When the metal-containing film ML is formed in step ST2 without generating plasma, this film deposition apparatus does not need to have a configuration for generating plasma.

[0102] Another process module among process modules PM1 to PM6 is a substrate processing apparatus, such as plasma processing apparatus 1 or another plasma processing apparatus. This substrate processing apparatus is used to etch the metal-containing film ML in step ST3 and to etch the silicon-containing film RE in step ST4. This substrate processing apparatus may include a second chamber and a second substrate support for supporting the substrate W within the second chamber. The control unit 2A is configured to control the substrate processing apparatus in the second chamber to expose the substrate W to the first plasma and etch the metal-containing film ML formed on the silicon-containing film RE. In addition, the control unit 2A is configured to control the substrate processing apparatus in the second chamber to expose the substrate W to the second plasma and etch the silicon-containing film RE. This substrate processing apparatus may be used to remove the mask MK in step ST5. Alternatively, the etching of the metal-containing film ML in step ST3 may be performed using a substrate processing apparatus, which is yet another process module among process modules PM1 to PM6. The process module in which the etching of the metal-containing film ML in step ST3 is performed may be different from the process module in which the etching of the silicon-containing film RE in step ST4 is performed. Furthermore, the removal of the mask MK in step ST5 may be performed using a substrate processing device, which is yet another process module from among the process modules PM1 to PM6. The process module in which the removal of the mask MK in step ST5 is performed may be different from the process module in which steps ST3 and ST4 are performed.

[0103] In the substrate processing system PS, the control unit 2A is configured to control various parts of the substrate processing system PS in addition to the functions of the control unit 2. The control unit 2A is configured to control the film deposition apparatus to form a metal-containing film ML in process ST2. After the metal-containing film ML is formed, the control unit 2A is configured to control the substrate processing apparatus to etch the metal-containing film in process ST3 and the silicon-containing film RE in process ST4. This substrate processing system PS can transport the substrate W between process modules without contacting it with the atmosphere.

[0104] Another process module among process modules PM1 to PM6 may be a developing device. Step ST1 in method MT1 may include a developing step. In the developing step, an opening OP1 may be formed in the mask MK within the developing device. Furthermore, after development, a metal-containing film ML may be formed in the developing device on the silicon-containing film RE exposed on the mask MK and at the bottom OP1a.

[0105] The formation of the metal-containing film ML in step ST2 and the etching of the metal-containing film ML and silicon-containing film RE in steps ST3 and ST4 (or, if step ST3 is not included, the formation of the metal-containing film ML in step ST2 and the etching of the silicon-containing film RE in step ST4) may each be performed by separate devices. That is, steps ST2, ST3, and ST4 (or, if step ST3 is not included, steps ST2 and ST4) may each be performed by standalone devices. In this case, the substrate W may be transported in the atmosphere from the device that performed step ST2 by a transport device, etc., and the substrate W may be brought into the device that performs steps ST3 and ST4 (or, if step ST3 is not included, step ST4).

[0106] The following describes various experiments conducted to evaluate Methods MT1 to MT4. The experiments described below are not limiting to this disclosure.

[0107] (First Experiment) In the first experiment, a substrate was first placed on the substrate support in the chamber of the plasma processing apparatus (step ST1). The substrate included a silicon-containing film and a mask formed on the silicon-containing film, which included an opening. The silicon-containing film was a multilayer film containing silicon oxide and silicon nitride. The mask contained an amorphous carbon film. Next, as the first sample, a substrate was prepared with nothing formed on the silicon-containing film exposed on the mask and at the bottom of the opening. Subsequently, the silicon-containing film was etched by supplying the first sample with a first processing gas and a second processing gas (steps ST3 and ST4). The same gas was used for the first and second processing gases. The gas contained hydrogen fluoride gas. The temperature of the substrate support was 0°C. The shapes of the opening and recess of the first sample were measured after etching.

[0108] (Second Experiment) The experiment was carried out in the same manner as the first experiment, except for the following points. After step ST1, a substrate was prepared as the second sample, on which a carbon film was formed on the silicon-containing film exposed on the mask and at the bottom of the opening (step ST2). The thickness of the carbon-containing film in the second sample was approximately 5 nm. Subsequently, the first and second processing gases were supplied to the second sample to etch the silicon-containing film and the carbon film formed on the silicon-containing film (steps ST3 and ST4).

[0109] (Third Experiment) The experiment was carried out in the same manner as the first experiment, except for the following points. After step ST1, a substrate was prepared as the third sample, in which a tin-containing film was formed on the silicon-containing film exposed on the mask and at the bottom of the opening (step ST2). The tin-containing film in the third sample was tin oxide (SnO ｘ ) Furthermore, when forming the tin-containing film, tetrakis(dimethylamino)tin-containing gas was supplied as a precursor gas, and oxygen gas was supplied as a reaction gas. The temperature of the substrate support was 150°C. The thickness of the tin-containing film in the third sample was approximately 5 nm. Subsequently, the first and second processing gases were supplied to the third sample to etch the silicon-containing film and the tin-containing film formed on the silicon-containing film (steps ST3 and ST4).

[0110] (First Experimental Results) Figure 28 is a graph showing the patterns of the mask openings and silicon-containing film recesses after etching for the first to third samples. In Figure 28, the horizontal axis represents the pattern width, and the vertical axis represents the pattern depth. On the vertical axis, values ​​above 0 μm indicate the height of the mask opening, and values ​​below 0 μm indicate the depth of the silicon-containing film recesses. As shown in Figure 28, regarding the pattern width from the top (around 1.5 μm) to the bottom (around 0 μm) of the mask opening, the pattern width of the third sample SP3 is the closest to vertical. In contrast, it can be seen that the pattern width gradually widens in the order of the second sample SP2 and the first sample SP1. In particular, it can be seen that the pattern width widens in the middle (around 1 μm) in the order of the second sample SP2 and the first sample SP1. Furthermore, regarding the pattern width from the top (around 0 μm) to the bottom (around -2 μm) of the silicon-containing film recesses, the pattern width of the third sample SP3 is the closest to vertical. In contrast, it can be seen that the pattern width gradually widens in the order of the second sample SP2 and the first sample SP1. In particular, it can be seen that the pattern width widens from the top to the middle (around 0 μm to -0.5 μm) in the order of the second sample SP2 and the first sample SP1. From the above, it can be said that the shape abnormalities in the openings and recesses of the third sample SP3, on which the tin-containing film was formed, are suppressed compared to the first sample SP1, on which nothing was formed on the silicon-containing film, and the second sample SP2, on which the carbon film was formed.

[0111] (Fourth Experiment) The experiment was conducted in the same manner as the first experiment, except for the following points. After step ST1, a substrate was prepared as the fourth sample, in which a gallium-containing film was formed on the silicon-containing film exposed on the mask and at the bottom of the opening (step ST2). The gallium-containing film in the fourth sample was gallium oxide (GaO ｘ Next, the first and second processing gases were supplied to the fourth sample to etch the silicon-containing film and the gallium-containing film formed on the silicon-containing film (steps ST3 and ST4).

[0112] (Experiment 5) The experiment was conducted in the same manner as in Experiment 1, except for the following points. After step ST1, a substrate was prepared as the fifth sample, in which a titanium-containing film was formed on the silicon-containing film exposed on the mask and at the bottom of the opening (step ST2). The titanium-containing film in the fifth sample was titanium oxide (TiO2). ｘ Next, the first and second processing gases were supplied to the fifth sample to etch the silicon-containing film and the titanium-containing film formed on the silicon-containing film (steps ST3 and ST4).

[0113] (Second Experimental Results) Figure 29 is a graph showing the patterns of the mask openings and the recesses of the silicon-containing film after etching for the first sample SP1, the fourth sample SP4, and the fifth sample SP5. In Figure 29, the horizontal axis represents the pattern width, and the vertical axis represents the pattern depth. On the vertical axis, the area above the dashed line represents the height of the mask opening, and the area below the dashed line represents the depth of the recesses in the silicon-containing film. First, regarding the pattern width from the top to the bottom of the mask opening, the pattern width of the fourth sample SP4 is the closest to vertical. The pattern width of the fifth sample SP5 is closer to vertical than that of the first sample SP1. Next, regarding the pattern width in the recesses of the silicon-containing film, it can be seen that the pattern width spreads in the order of the first sample SP1, the fourth sample SP4, and the fifth sample SP5. Based on the above, it can be said that the shape abnormalities in the recesses of the silicon-containing film in the fifth sample SP5, on which the titanium-containing film was formed, were suppressed compared to the first sample SP1, on which nothing was formed on the silicon-containing film, and the fourth sample SP4, on which the gallium-containing film was formed.

[0114] (Third Experimental Results) Figure 30 is a graph showing the patterns of the mask openings and silicon-containing film recesses after etching for the third sample SP3, the fourth sample SP4, and the fifth sample SP5. First, regarding the pattern width from the top to the bottom of the mask opening, the pattern width of the third sample SP3 is the closest to vertical. Next, regarding the pattern width in the silicon-containing film recesses, it can be seen that the pattern width spreads smaller in the order of the fourth sample SP4, the fifth sample SP5, and the third sample SP3. From the above, it can be said that the shape abnormalities in the openings and recesses of the third sample SP3, on which the tin-containing film was formed, are suppressed compared to the fourth sample SP4, on which the gallium-containing film was formed, and the fifth sample SP5, on which the titanium-containing film was formed.

[0115] (Experiment 6) The experiment was conducted in the same manner as in Experiment 1, except for the following points. After step ST1, a substrate was prepared as the sixth sample, with a tantalum-containing film formed on the silicon-containing film exposed on the mask and at the bottom of the opening (step ST2). The tantalum-containing film in the sixth sample was tantalum oxide (TaO ｘ Next, the first and second processing gases were supplied to the sixth sample to etch the silicon-containing film and the tantalum-containing film formed on the silicon-containing film (steps ST3 and ST4).

[0116] (Results of Experiment 4) Figure 31 is a graph showing the patterns of the mask openings and the recesses of the silicon-containing film after etching for the first sample SP1, the third sample SP3, and the sixth sample SP6. First, regarding the pattern width from the top to the bottom of the mask opening, the pattern width of the third sample SP3 is the closest to vertical. Next, regarding the pattern width in the recesses of the silicon-containing film, it can be seen that the pattern width spreads smaller in the order of the first sample SP1, the third sample SP3, and the sixth sample SP6. From the above, it can be said that the shape abnormalities in the recesses of the silicon-containing film in the sixth sample SP6, where a tantalum-containing film was formed, are suppressed compared to the third sample SP3, where a tin-containing film was formed. One possible reason for this is the following mechanism, but it is not limited to this. In step ST4, when etching the silicon-containing film with the second processing gas, the metal-containing film formed on the sidewall of the mask opening in step ST2 is mixed with the second processing gas, and the metal-containing film may be formed again on the sidewall of the recess of the silicon-containing film. In this case, the tantalum-containing film may be more easily formed in the recesses of the silicon-containing film than the tin-containing film. As a result, the sidewall protection effect of the tantalum-containing film can be enhanced compared to the sidewall protection effect of the tin-containing film.

[0117] (Experiment 7) The experiment was carried out in the same manner as in Experiment 6, except for the following points, and the seventh sample was prepared. In step ST3, the first processing gas contained hydrogen fluoride gas, and in step ST4, the second processing gas contained hydrogen fluoride gas.

[0118] (Experiment 8) The experiment was carried out in the same manner as in Experiment 6, except for the following points, and the eighth sample was prepared. In step ST3, the first processing gas contains hydrogen fluoride gas and further contains phosphorus-containing gas at the first flow rate. In step ST4, the second processing gas contains hydrogen fluoride gas and further contains phosphorus-containing gas at the first flow rate.

[0119] (Experiment 9) The experiment was conducted in the same manner as in Experiment 6, except for the following points, and the ninth sample was prepared. In step ST3, the first processing gas contains hydrogen fluoride gas and also contains phosphorus-containing gas at the second flow rate. In step ST4, the second processing gas contains hydrogen fluoride gas and also contains phosphorus-containing gas at the second flow rate. The second flow rate is greater than the first flow rate.

[0120] (Experiment 10) The experiment was carried out in the same manner as in Experiment 6, except for the following points, and the 10th sample was prepared. In step ST3, the first processing gas contains hydrogen fluoride gas and further contains phosphorus-containing gas at a third flow rate. In step ST4, the second processing gas contains hydrogen fluoride gas and further contains phosphorus-containing gas at a third flow rate. The third flow rate is greater than the second flow rate.

[0121] (Results of Experiment 5) Figure 32 is a graph showing the patterns of the mask openings and recesses in the silicon-containing film after etching for samples SP7 to SP10. Regarding the pattern width in the recesses of the silicon-containing film, it can be seen that the pattern width spreads in the order of SP7, SP8, SP9, and SP10. Furthermore, regarding the pattern width from the top to the bottom of the recesses of the silicon-containing film, the pattern width of SP10 is the closest to vertical. From the above, it can be said that in processes ST3 and ST4, the larger the flow rate of phosphorus-containing gas included in the first and second processing gases, the more the shape abnormalities in the recesses of the silicon-containing film are suppressed. One possible reason for this is that the reactants derived from hydrogen fluoride are replaced by reactants derived from phosphorus, and the tantalum removal rate is reduced, but this is not the only reason.

[0122] Herein, various exemplary embodiments included in this disclosure are described in [E1] to [E29] below.

[0123] [E1] A substrate processing method comprising: (a) a step of providing a substrate, the substrate comprising a silicon-containing film and a mask formed on the silicon-containing film and including an opening, wherein the silicon-containing film is exposed at the bottom of the opening; (b) a step of forming a metal-containing film on the mask and on the silicon-containing film exposed at the bottom; (c) a step of exposing the substrate to a first plasma generated from a first processing gas containing a halogen-containing gas to etch the metal-containing film formed on the silicon-containing film; and (d) a step of exposing the substrate to a second plasma generated from a second processing gas containing a hydrogen halide gas to etch the silicon-containing film.

[0124] [E2] The substrate processing method according to [E1], wherein the metal-containing film comprises at least one selected from the group consisting of tin, titanium, and molybdenum.

[0125] [E3] The substrate processing method according to [E1] or [E2], wherein the metal-containing film contains tin.

[0126] [E4] The silicon-containing film comprises at least one selected from the group consisting of a multilayer film, a silicon oxide film, a silicon nitride film, and a polysilicon film, and the multilayer film comprises at least two films from among a silicon oxide film, a silicon nitride film, and a phosphorus-containing silicon film, the substrate processing method according to any one of [E1] to [E3].

[0127] [E5] The substrate processing method according to any one of [E1] to [E4], wherein the mask comprises a carbon-containing film.

[0128] [E6] The substrate processing method according to any one of [E1] to [E5], wherein in (b), the metal-containing film is formed by at least one selected from the group consisting of atomic layer deposition, chemical vapor deposition, and molecular layer deposition.

[0129] [E7] The substrate processing method according to any one of [E1] to [E6], wherein (b) is a step of forming a precursor layer containing a tin-containing substance on the silicon-containing film on the mask and on the bottom, and (b) a step of exposing the precursor layer to a reaction gas to form the metal-containing film from the precursor layer.

[0130] [E8] The substrate processing method according to any one of [E1] to [E7], wherein the halogen-containing gas includes hydrogen halide gas.

[0131] [E9] The substrate processing method according to [E8], wherein the hydrogen halide gas used in (c) is the same gas as the hydrogen halide gas used in (d).

[0132] [E10] The substrate processing method according to [E8] or [E9], wherein the hydrogen halogen gas used in (c) and the hydrogen halogen gas used in (d) include hydrogen fluoride gas.

[0133] [E11] The substrate processing method according to any one of [E1] to [E7], wherein the halogen-containing gas includes a chlorine-containing gas.

[0134] [E12] The substrate processing method according to [E11], wherein the chlorine-containing gas comprises chlorine gas.

[0135] [E13] The substrate processing method according to any one of [E1] to [E12], wherein the first processing gas and the second processing gas further comprise at least one selected from the group consisting of carbon-containing gases, phosphorus-containing gases, halogen-containing gases, and metal-containing gases.

[0136] [E14] The substrate processing method according to any one of [E1] to [E13], wherein in (c) and (d), the first processing gas and the second processing gas are continuously supplied into the chamber containing the substrate.

[0137] [E15] The substrate processing method according to any one of [E1] to [E14], wherein in (c) and (d), the first plasma and the second plasma are generated in succession.

[0138] [E16] The substrate processing method according to any one of [E1] to [E15], wherein the temperature of the substrate support portion supporting the substrate in (b) is higher than the temperature of the substrate support portion supporting the substrate in (c).

[0139] [E17] The substrate processing method according to any one of [E1] to [E16], wherein the temperature of the substrate support portion supporting the substrate in (c) is 0°C or lower.

[0140] [E18] The substrate processing method according to any one of [E1] to [E17], wherein (b) is performed before a recess is formed in the silicon-containing film exposed at the bottom.

[0141] [E19] The substrate processing method according to any one of [E1] to [E18], wherein the chamber in which (b) is performed is the same as the chamber in which (c) is performed.

[0142] [E20] The substrate processing method according to any one of [E1] to [E18], wherein the chamber in which (b) is performed is different from the chamber in which (c) is performed.

[0143] [E21] The substrate processing method according to any one of [E1] to [E20], wherein the opening of the mask included in the substrate provided in (a) has a first opening dimension at a first position in the thickness direction of the substrate and a second opening dimension smaller than the first opening dimension at a second position different from the first position, and (b) includes the step of forming the metal-containing film such that the opening has a third opening dimension at the first position when the metal-containing film is formed on the mask, wherein the third opening dimension is smaller than the first opening dimension and less than or equal to the second opening dimension.

[0144] [E22] The substrate processing method according to any one of [E1] to [E20], wherein the opening of the mask included in the substrate provided in (a) has a first opening dimension, and (b) includes the step of forming the metal-containing film such that the opening has a second opening dimension when the metal-containing film is formed on the mask, wherein the second opening dimension is smaller than the first opening dimension.

[0145] [E23] The method for processing a substrate according to any one of [E1] to [E20], wherein the opening of the mask included in the substrate provided in (a) has a first opening dimension at a first position in the thickness direction of the substrate, and a second opening dimension smaller than the first opening dimension at a second position closer to the bottom than the first position, the mask further includes a side wall defining the opening, and (b) comprises the step of conformally forming the metal-containing film on the side wall.

[0146] [E24] The substrate processing method according to any one of [E1] to [E20], wherein the opening of the mask included in the substrate provided in (a) has a first opening dimension, the first opening dimension is constant in the thickness direction of the substrate, and (b) includes the step of forming the metal-containing film such that, when the metal-containing film is formed on the mask, the opening has a second opening dimension at a first position in the thickness direction and a third opening dimension at a second position closer to the bottom than the first position, the third opening dimension is smaller than the second opening dimension.

[0147] [E25] A substrate processing method comprising: (a) a step of providing a substrate, the substrate comprising a silicon-containing film and a mask formed on the silicon-containing film and including an opening, wherein the silicon-containing film is exposed at the bottom of the opening; (b) a step of forming a metal-containing film on the mask; and (c) a step of etching the silicon-containing film by exposing the substrate to a plasma generated from a processing gas containing hydrogen halide gas.

[0148] [E26] A substrate processing method comprising: (a) a step of providing a substrate on a substrate support portion in a chamber, wherein the substrate comprises a silicon-containing film, a mask formed on the silicon-containing film and including an opening including a bottom portion on which the silicon-containing film is exposed, and a metal-containing film formed on the mask and on the silicon-containing film exposed at the bottom portion; (b) a step of exposing the substrate to a first plasma generated from a first processing gas containing a halogen-containing gas to etch the metal-containing film formed on the silicon-containing film; and (c) a step of exposing the substrate to a second plasma generated from a second processing gas containing a hydrogen halide gas to etch the silicon-containing film.

[0149] [E27] A substrate processing method comprising: (a) a step of providing a substrate on a substrate support portion in a chamber, wherein the substrate comprises a silicon-containing film, a mask formed on the silicon-containing film and including an opening including a bottom portion where the silicon-containing film is exposed, and a metal-containing film formed on the mask; and (b) a step of etching the silicon-containing film by exposing the substrate to a plasma generated from a processing gas containing hydrogen halide gas.

[0150] [E28] A substrate processing apparatus comprising: a chamber; a substrate support for supporting a substrate within the chamber; a gas supply unit configured to supply a first processing gas and a second processing gas into the chamber, wherein the first processing gas contains a halogen-containing gas and the second processing gas contains a hydrogen halide gas; a plasma generation unit configured to generate a first plasma from the first processing gas within the chamber and a second plasma from the second processing gas within the chamber; and a control unit, wherein the substrate includes a silicon-containing film; a mask formed on the silicon-containing film and including an opening including a bottom portion where the silicon-containing film is exposed; and a metal-containing film formed on the mask and on the silicon-containing film exposed at the bottom portion, and the control unit configured to control the gas supply unit and the plasma generation unit so as to expose the substrate to the first plasma to etch the metal-containing film formed on the silicon-containing film, and expose the substrate to the second plasma to etch the silicon-containing film.

[0151] [E29] A first chamber, a second chamber, a first substrate support for supporting a substrate in the first chamber, a second substrate support for supporting the substrate in the second chamber, a gas supply unit configured to supply a first processing gas and a second processing gas into the second chamber, wherein the first processing gas contains a halogen-containing gas and the second processing gas contains a hydrogen halide gas, a plasma generation unit configured to generate a first plasma from the first processing gas in the second chamber and a second plasma from the second processing gas in the second chamber, and a control unit, wherein the substrate includes a silicon-containing film and a mask formed on the silicon-containing film and including an opening including a bottom where the silicon-containing film is exposed, the control unit, in the first chamber, forms a metal-containing film on the mask and on the silicon-containing film exposed at the bottom, and in the second chamber, exposes the substrate to the first plasma to etch the metal-containing film formed on the silicon-containing film. A substrate processing system configured to control the gas supply unit and the plasma generation unit in the second chamber so as to expose the substrate to the second plasma and etch the silicon-containing film.

[0152] 1...Plasma processing apparatus (substrate processing apparatus), 2, 2A...Control unit, 10...Plasma processing chamber (chamber), 11...Substrate support unit, 12...Plasma generation unit, 20...Gas supply unit, MK...Mask, ML...Metal-containing film, OP1...Opening, OP1a...Bottom, OP2...Recess, PS...Substrate processing system, RE...Silicon-containing film, W...Substrate.

Claims

1. A substrate processing method comprising: (a) a step of providing a substrate, the substrate comprising a silicon-containing film and a mask formed on the silicon-containing film and including an opening, wherein the silicon-containing film is exposed at the bottom of the opening; (b) a step of forming a metal-containing film on the mask and on the silicon-containing film exposed at the bottom; (c) a step of exposing the substrate to a first plasma generated from a first processing gas containing a halogen-containing gas to etch the metal-containing film formed on the silicon-containing film; and (d) a step of exposing the substrate to a second plasma generated from a second processing gas containing a hydrogen halide gas to etch the silicon-containing film.

2. The substrate processing method according to claim 1, wherein the metal-containing film comprises at least one selected from the group consisting of tin, titanium, and molybdenum.

3. The substrate processing method according to claim 1 or 2, wherein the metal-containing film contains tin.

4. The substrate processing method according to claim 1 or 2, wherein the silicon-containing film comprises at least one selected from the group consisting of a multilayer film, a silicon oxide film, a silicon nitride film, and a polysilicon film, and the multilayer film comprises at least two films selected from a silicon oxide film, a silicon nitride film, and a phosphorus-containing silicon film.

5. The substrate processing method according to claim 1 or 2, wherein the mask includes a carbon-containing film.

6. The substrate processing method according to claim 1 or 2, wherein the metal-containing film is formed by at least one selected from the group consisting of atomic layer deposition, chemical vapor deposition, and molecular layer deposition, in (b) above.

7. The substrate processing method according to claim 1 or 2, wherein (b) comprises: (b-1) forming a precursor layer containing a tin-containing substance on the silicon-containing film on the mask and on the bottom; and (b-2) exposing the precursor layer to a reaction gas to form the metal-containing film from the precursor layer.

8. The substrate processing method according to claim 1 or 2, wherein the halogen-containing gas includes hydrogen halide gas.

9. The substrate processing method according to claim 8, wherein the hydrogen halide gas used in (c) is the same gas as the hydrogen halide gas used in (d).

10. The substrate processing method according to claim 8, wherein the hydrogen halogen gas used in (c) and the hydrogen halogen gas used in (d) include hydrogen fluoride gas.

11. The substrate processing method according to claim 1 or 2, wherein the halogen-containing gas includes a chlorine-containing gas.

12. The substrate processing method according to claim 11, wherein the chlorine-containing gas includes chlorine gas.

13. The substrate processing method according to claim 1 or 2, wherein the first processing gas and the second processing gas further include at least one selected from the group consisting of carbon-containing gases, phosphorus-containing gases, halogen-containing gases, and metal-containing gases.

14. The substrate processing method according to claim 1 or 2, wherein in (c) and (d), the first processing gas and the second processing gas are continuously supplied into the chamber containing the substrate.

15. The substrate processing method according to claim 1 or 2, wherein in (c) and (d), the first plasma and the second plasma are generated in succession.

16. The substrate processing method according to claim 1 or 2, wherein the temperature of the substrate support portion supporting the substrate in (b) is higher than the temperature of the substrate support portion supporting the substrate in (c).

17. The substrate processing method according to claim 1 or 2, wherein the temperature of the substrate support portion supporting the substrate in (c) is 0°C or lower.

18. The substrate processing method according to claim 1 or 2, wherein (b) is performed before a recess is formed in the silicon-containing film exposed at the bottom.

19. The substrate processing method according to claim 1 or 2, wherein the chamber in which (b) is performed is the same as the chamber in which (c) is performed.

20. The substrate processing method according to claim 1 or 2, wherein the chamber in which (b) is performed is different from the chamber in which (c) is performed.

21. The substrate processing method according to claim 1 or 2, wherein the opening of the mask included in the substrate provided in (a) has a first opening dimension at a first position in the thickness direction of the substrate and a second opening dimension smaller than the first opening dimension at a second position different from the first position, and (b) includes the step of forming the metal-containing film such that the opening has a third opening dimension at the first position when the metal-containing film is formed on the mask, the third opening dimension being smaller than the first opening dimension and less than or equal to the second opening dimension.

22. The substrate processing method according to claim 1 or 2, wherein the opening of the mask included in the substrate provided in (a) has a first opening dimension, and (b) includes the step of forming the metal-containing film such that the opening has a second opening dimension when the metal-containing film is formed on the mask, the second opening dimension being smaller than the first opening dimension.

23. The method for processing a substrate according to claim 1 or 2, wherein the opening of the mask included in the substrate provided in (a) has a first opening dimension at a first position in the thickness direction of the substrate and a second opening dimension smaller than the first opening dimension at a second position closer to the bottom than the first position, the mask further includes a side wall defining the opening, and (b) comprises the step of conformally forming the metal-containing film on the side wall.

24. The substrate processing method according to claim 1 or 2, wherein the opening of the mask included in the substrate provided in (a) has a first opening dimension, the first opening dimension is constant in the thickness direction of the substrate, and (b) includes the step of forming the metal-containing film such that, when the metal-containing film is formed on the mask, the opening has a second opening dimension at a first position in the thickness direction and a third opening dimension at a second position closer to the bottom than the first position, the third opening dimension being smaller than the second opening dimension.

25. A substrate processing method comprising: (a) a step of providing a substrate, the substrate comprising a silicon-containing film and a mask formed on the silicon-containing film and including an opening, wherein the silicon-containing film is exposed at the bottom of the opening; (b) a step of forming a metal-containing film on the mask; and (c) a step of etching the silicon-containing film by exposing the substrate to a plasma generated from a processing gas containing hydrogen halide gas.

26. A substrate processing method comprising: (a) a step of providing a substrate on a substrate support portion in a chamber, wherein the substrate includes a silicon-containing film, a mask formed on the silicon-containing film and including an opening including a bottom portion on which the silicon-containing film is exposed, and a metal-containing film formed on the mask and on the silicon-containing film exposed at the bottom portion; (b) a step of exposing the substrate to a first plasma generated from a first processing gas containing a halogen-containing gas to etch the metal-containing film formed on the silicon-containing film; and (c) a step of exposing the substrate to a second plasma generated from a second processing gas containing a hydrogen halide gas to etch the silicon-containing film.

27. A substrate processing method comprising: (a) a step of providing a substrate on a substrate support portion in a chamber, wherein the substrate comprises a silicon-containing film, a mask formed on the silicon-containing film and including an opening including a bottom portion where the silicon-containing film is exposed, and a metal-containing film formed on the mask; and (b) a step of etching the silicon-containing film by exposing the substrate to a plasma generated from a processing gas containing hydrogen halide gas.

28. A substrate processing apparatus comprising: a chamber; a substrate support for supporting a substrate within the chamber; a gas supply unit configured to supply a first processing gas and a second processing gas into the chamber, wherein the first processing gas contains a halogen-containing gas and the second processing gas contains a hydrogen halide gas; a plasma generation unit configured to generate a first plasma from the first processing gas within the chamber and a second plasma from the second processing gas within the chamber; and a control unit, wherein the substrate includes a silicon-containing film; a mask formed on the silicon-containing film and including an opening including a bottom portion where the silicon-containing film is exposed; and a metal-containing film formed on the mask and on the silicon-containing film exposed at the bottom portion; and the control unit configured to control the gas supply unit and the plasma generation unit so as to expose the substrate to the first plasma to etch the metal-containing film formed on the silicon-containing film, and expose the substrate to the second plasma to etch the silicon-containing film.

29. A first chamber, a second chamber, a first substrate support for supporting a substrate in the first chamber, a second substrate support for supporting the substrate in the second chamber, a gas supply unit configured to supply a first processing gas and a second processing gas into the second chamber, wherein the first processing gas contains a halogen-containing gas and the second processing gas contains a hydrogen halide gas, a plasma generation unit configured to generate a first plasma from the first processing gas in the second chamber and a second plasma from the second processing gas in the second chamber, and a control unit, wherein the substrate includes a silicon-containing film and a mask formed on the silicon-containing film and including an opening including a bottom where the silicon-containing film is exposed, the control unit, in the first chamber, forms a metal-containing film on the mask and on the silicon-containing film exposed at the bottom, and in the second chamber, exposes the substrate to the first plasma to etch the metal-containing film formed on the silicon-containing film. A substrate processing system configured to control the gas supply unit and the plasma generation unit in the second chamber so as to expose the substrate to the second plasma and etch the silicon-containing film.

Images