Substrate processing method and substrate processing apparatus

Abstract

In one exemplary embodiment of the present invention, the method is a method for processing a substrate provided with a film to be etched and a mask provided on the film to be etched and having an opening. The method includes: (a) forming a first layer containing nitrogen atoms and hydrogen atoms on a side wall of a recess formed in the film to be etched corresponding to the opening by using a first processing gas; (b) forming a second layer from the first layer using a second processing gas containing a phosphorus-containing gas; and (c) etching the recess using a third processing gas.

Description

Technical Field

[0001] Exemplary embodiments of the present invention relate to a substrate processing method and a substrate processing apparatus. Background Art

[0002] Patent document 1 discloses a method for forming a recess in a dielectric layer by etching. In this method, a mask is formed on the dielectric layer. Then, a film containing protective silicon is formed on the mask. Then, the recess is formed by etching using the mask and the film containing protective silicon.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2008-60566 Summary of the invention

[0006] Technical issues to be solved by the invention

[0007] The present invention provides a technology for suppressing shape defects of a side wall of a recessed portion during etching.

[0008] Means for solving technical problems

[0009] In an exemplary embodiment of the method provided by the present invention, the method is a method for processing a substrate having an etching target film and a mask provided on the etching target film and having an opening, and the method comprises the following steps:

[0010] (a) forming a first layer containing nitrogen atoms and hydrogen atoms on a side wall of a recessed portion formed on the etching target film corresponding to the opening using a first processing gas;

[0011] (b) forming a second layer from the first layer using a second process gas including a phosphorus-containing gas; and

[0012] (c) Etching the concave portion using a third process gas.

[0013] Effects of the Invention

[0014] According to one exemplary embodiment, it is possible to suppress shape defects of the side walls of the recessed portion during etching. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 FIG. 1 is a diagram schematically showing a substrate processing apparatus according to an exemplary embodiment.

[0016] Figure 2 FIG. 1 is a diagram schematically showing a substrate processing apparatus according to an exemplary embodiment.

[0017] Figure 3is a flow chart of a substrate processing method according to an exemplary embodiment.

[0018] Figure 4 This is a partially enlarged cross-sectional view of an example of a substrate.

[0019] Figure 5 is a cross-sectional view showing one process of a substrate processing method according to an exemplary embodiment.

[0020] Figure 6 is a cross-sectional view showing one process of a substrate processing method according to an exemplary embodiment.

[0021] Figure 7 is a cross-sectional view showing one process of a substrate processing method according to an exemplary embodiment.

[0022] Figure 8 is a cross-sectional view showing one process of a substrate processing method according to an exemplary embodiment.

[0023] Fig. 9 FIG. 1 is a partially enlarged cross-sectional view of an example of a substrate obtained by performing a substrate processing method according to an exemplary embodiment. DETAILED DESCRIPTION

[0024] Hereinafter, various exemplary embodiments will be described in detail with reference to the accompanying drawings. In addition, in each of the drawings, the same or equivalent parts are marked with the same symbols.

[0025] Figure 1 : is a diagram for illustrating a structural example of a plasma processing system. In one embodiment, the plasma processing system includes a plasma processing device 1 and a control unit 2. The plasma processing system is an example of a substrate processing system, and the plasma processing device 1 is an example of a substrate processing device. The plasma processing device 1 includes a plasma processing chamber 10, a substrate support portion 11, and a plasma generating portion 12. The plasma processing chamber 10 has a plasma processing space. In addition, the plasma processing chamber 10 has: at least one gas supply port for supplying at least one processing gas to the plasma processing space; and at least one gas exhaust port for exhausting gas from the plasma processing space. The gas supply port is connected to the gas supply portion 20 described later, and the gas exhaust port is connected to the exhaust system 40 described later. The substrate support portion 11 is arranged in the plasma processing space and has a substrate supporting surface for supporting a substrate.

[0026] The plasma generating unit 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma formed in the plasma processing space may be a capacitively coupled plasma (CCP; Capacitively Coupled Plasma), an inductively coupled plasma (ICP; Inductively Coupled Plasma), an ECR plasma (Electron-Cyclotron-resonance plasma, electron cyclotron resonance plasma), a helicon wave excited plasma (HWP: Helicon Wave Plasma) or a surface wave plasma (SWP: Surface Wave Plasma), etc. In addition, various types of plasma generating units including an AC (Alternating Current, alternating current) plasma generating unit and a DC (Direct Current, direct current) plasma generating unit may be used. In one embodiment, the AC signal (AC power) used in the AC plasma generating unit has a frequency in the range of 100kHz to 10GHz. Therefore, the AC signal includes an RF (Radio Frequency, radio frequency) signal and a microwave signal. In one embodiment, the RF signal has a frequency in the range of 100kHz to 150MHz.

[0027] The control unit 2 processes computer executable commands that cause the plasma processing device 1 to execute the various processes described in the present invention. The control unit 2 can be configured to control the various elements of the plasma processing device 1 in a manner that executes the various processes described herein. In one embodiment, a part or all of the control unit 2 can be included in the plasma processing device 1. The control unit 2 can include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The control unit 2 is implemented, for example, by a computer 2a. The processing unit 2a1 can be configured to read a program from the storage unit 2a2 and execute the read program, thereby performing various control operations. The program can be pre-stored in the storage unit 2a2, or it can be obtained through a medium when necessary. The obtained program is stored in the storage unit 2a2, and is read and executed from the storage unit 2a2 by the processing unit 2a1. The medium can be various storage media that can be read to the computer 2a, or it can be a communication line connected to the communication interface 2a3. The processing unit 2a1 can also be a CPU (Central Processing Unit). The storage unit 2a2 may also include a RAM (Random Access Memory), a ROM (Read Only Memory), a HDD (Hard Disk Drive), an SSD (Solid State Drive), or a combination thereof. The communication interface 2a3 may also communicate with the plasma processing device 1 via a communication line such as a LAN (Local Area Network).

[0028] Hereinafter, a configuration example of a capacitively coupled plasma processing apparatus as an example of the plasma processing apparatus 1 will be described. Figure 2 It is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus.

[0029] The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply 30, and an exhaust system 40. Furthermore, the plasma processing apparatus 1 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 disposed in the plasma processing chamber 10. The shower head 13 is disposed 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 wall 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 frame of the plasma processing chamber 10.

[0030] The substrate support portion 11 includes a main body 111 and a ring assembly 112. The main body 111 has a central area 111a for supporting a substrate W, and an annular area 111b for supporting the ring assembly 112. A wafer is an example of a substrate W. When viewed from above, the annular area 111b of the main body 111 surrounds the central area 111a of the main body 111. The substrate W is arranged on the central area 111a of the main body 111, and the ring assembly 112 is arranged on the annular area 111b of the main body 111 in a manner that surrounds the substrate W on the central area 111a of the main body 111. Therefore, the central area 111a is also referred to as a substrate supporting surface for supporting the substrate W, and the annular area 111b is also referred to as a ring supporting surface for supporting the ring assembly 112.

[0031] In one embodiment, the main body 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive component. The conductive component of the base 1110 can function as a lower electrode. The electrostatic chuck 1111 is arranged on the base 1110. The electrostatic chuck 1111 includes a ceramic component 1111a and an electrostatic electrode 1111b arranged in the ceramic component 1111a. The ceramic component 1111a has a central area 111a. In one embodiment, the ceramic component 1111a also has an annular area 111b. In addition, other components surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating component, may also have an annular area 111b. In this case, the ring assembly 112 may be arranged on the annular electrostatic chuck or the annular insulating component, or on both the electrostatic chuck 1111 and the annular insulating component. Furthermore, at least one RF / DC electrode combined with the RF power supply 31 and / or DC power supply 32 described later may also be arranged in the ceramic component 1111a. In this case, at least one RF / DC electrode functions as a lower electrode. When the bias RF signal and / or DC signal described later is supplied to at least one RF / DC electrode, the RF / DC electrode is also referred to as a bias electrode. In addition, the conductive component of the base 1110 and at least one RF / DC electrode may also function as a plurality of lower electrodes. Furthermore, the electrostatic electrode 1111b may also function as a lower electrode. Therefore, the substrate support portion 11 includes at least one lower electrode.

[0032] The ring assembly 112 includes one or more ring-shaped components. In one embodiment, the one or more ring-shaped components include one or more edge rings and at least one cover ring. The edge ring is formed of a conductive material or an insulating material, and the cover ring is formed of an insulating material.

[0033] Furthermore, the substrate support portion 11 may include a temperature adjustment module configured to adjust at least one of the electrostatic chuck 1111, the ring assembly 112, and the substrate to a target temperature. The temperature adjustment module may include a heater, a heat transfer medium, a flow path 1110a, or a combination thereof. A heat transfer fluid such as salt water or gas flows through the flow path 1110a. In one embodiment, the flow path 1110a is formed in the base 1110, and one or more heaters are arranged in the ceramic component 1111a of the electrostatic chuck 1111. Furthermore, the substrate support portion 11 may include a heat transfer gas supply portion configured to supply a heat transfer gas to the gap between the back side of the substrate W and the central area 111a.

[0034] The shower head 13 is configured to introduce at least one processing gas from the gas supply part 20 into the plasma processing space 10s. The shower head 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b and a plurality of gas introduction ports 13c. The processing gas supplied to the gas supply port 13a is introduced into the plasma processing space 10s from the plurality of gas introduction ports 13c through the gas diffusion chamber 13b. In addition, the shower head 13 includes at least one upper electrode. In addition, in addition to the shower head 13, the gas introduction part may also include one or more side gas injection parts (SGI: Side Gas Injector) installed on one or more openings formed on the side wall 10a.

[0035] The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one process gas from each corresponding gas source 21 to the shower head 13 via each corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. In addition, the gas supply unit 20 may include at least one flow modulation device for modulating or pulsing the flow of at least one process gas.

[0036] The power supply 30 includes an RF power supply 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply 31 is configured to supply at least one RF signal (RF power) to at least one lower electrode and / or at least one upper electrode. Thus, plasma is formed by at least one processing gas supplied to the plasma processing space 10s. Therefore, the RF power supply 31 can function as at least a part of the plasma generating unit 12. Furthermore, by supplying a bias RF signal to at least one lower electrode, a bias potential is generated on the substrate W, thereby being able to absorb ion components in the formed plasma into the substrate W.

[0037] In one embodiment, the RF power supply 31 includes a first RF generator 31a and a second RF generator 31b. The first RF generator 31a is configured to be coupled to at least one lower electrode and / or at least one upper electrode via at least one impedance matching circuit to generate a source RF signal (source RF power) for generating plasma. 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 generator 31a may be configured to generate a plurality of source RF signals having different frequencies. The generated one or more source RF signals are supplied to at least one lower electrode and / or at least one upper electrode.

[0038] The second RF generating unit 31b is configured to be coupled to at least one lower electrode via at least one impedance matching circuit to generate a bias RF signal (bias RF power). The frequency of the bias RF signal may be the same as or different from the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency lower than the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 100 kHz to 60 MHz. In one embodiment, the second RF generating unit 31b may be configured to generate 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. Furthermore, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0039] In addition, the power supply 30 may include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generating unit 32a and a second DC generating unit 32b. In one embodiment, the first DC generating unit 32a is configured to be connected to at least one lower electrode to generate a first DC signal. The generated first DC signal is applied to at least one lower electrode. In one embodiment, the second DC generating unit 32b is configured to be connected to at least one upper electrode to generate a second DC signal. The generated second DC signal is applied to at least one upper electrode.

[0040] In various embodiments, the first and second DC signals may be pulsed. In this case, a voltage pulse sequence is applied to at least one lower electrode and / or at least one upper electrode. The voltage pulse may have a rectangular, trapezoidal, triangular or a combination thereof pulse waveform. In one embodiment, a waveform generator for generating a voltage pulse sequence from a DC signal is connected between the first DC generator 32a and at least one lower electrode. Therefore, the first DC generator 32a and the waveform generator constitute a voltage pulse generator. In the case where the second DC generator 32b and the waveform generator constitute a voltage pulse generator, the voltage pulse generator is connected to at least one upper electrode. The voltage pulse may have a positive polarity or a negative polarity. Furthermore, the voltage pulse sequence may include one or more positive polarity voltage pulses and one or more negative polarity voltage pulses in one cycle. In addition, the first and second DC generators 32a, 32b may be provided on the basis of the RF power supply 31, or the first DC generator 32a may be provided instead of the second RF generator 31b.

[0041] The exhaust system 40 may be connected to a gas outlet 10e disposed at the bottom of the plasma processing chamber 10, for example. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure in the plasma processing space 10s is regulated by the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0042] Figure 3 is a flow chart of a substrate processing method according to an exemplary embodiment. Figure 3 The substrate processing method shown (hereinafter referred to as "method MT1") can be performed using the substrate processing apparatus of the above-mentioned embodiment. The method MT1 can be applied to a substrate W.

[0043] Figure 4 This is a partial enlarged cross-sectional view of a substrate. Figure 4 As shown in FIG. 1 , in one embodiment, the substrate W includes an etching target film RE and a mask MK. The mask MK is provided on the etching target film RE. The etching target film RE may also be provided on a base region.

[0044] The etching target film RE may also include a silicon-containing film. The silicon-containing film may contain nitrogen or may not contain nitrogen. The silicon-containing film may be a silicon oxide film (SiO 2 The silicon-containing film may be any single-layer film selected from silicon nitride film (SiN film), silicon oxynitride film (SiON film), silicon carbide film (SiC film), silicon carbide nitride film (SiCN film), organic silicon oxide film (SiOCH film), and silicon film (Si film), or a stacked film including at least two of them. The silicon-containing film may also be a multilayer film in which at least two silicon-containing films are alternately arranged. In addition, the silicon nitride film (SiN film), silicon oxynitride film (SiON film), or silicon carbide nitride film (SiCN film) is a silicon-containing film containing nitrogen. The silicon oxide film (SiO 2 The etching target film RE may include a film containing hydrogen. The etching target film RE may also include a film containing hydrogen. Examples of the hydrogen-containing gas include hydrogen and water vapor (H2O3). 2 O). The etching target film RE may include a film containing oxygen.

[0045] The mask MK has an opening OP. The mask MK may also have a plurality of openings OP. The opening OP may have a hole pattern or a line pattern. The width (CD: Critical Dimension) of the opening OP may be, for example, less than 100 nm. The distance between adjacent openings OP may be, for example, less than 100 nm. The mask MK may also include an organic film (carbon-containing film). The organic film may include at least one selected from the group consisting of a SOC (Spin On Carbon) film and an amorphous carbon film.

[0046] In the following, regarding the method MT1, a case where the method MT1 is applied to a substrate W using the substrate processing apparatus of the above-mentioned embodiment is taken as an example, and reference is made to Figure 3 to Figure 9 Provide explanation. Figures 5 to 8 Each of them is a cross-sectional view showing a process of a substrate processing method according to an exemplary embodiment. Fig. 9 1 is a partially enlarged cross-sectional view of an example of a substrate obtained by executing a substrate processing method according to an exemplary embodiment. In the case of using the plasma processing apparatus 1, the method MT1 can be executed in the plasma processing apparatus 1 by controlling each part of the plasma processing apparatus 1 by the control unit 2. In the method MT1, as Figure 2 As shown, a substrate W disposed on a substrate support 11 in a plasma processing chamber 10 is processed. The substrate W may be etched by the method MT1.

[0047] like Figure 3 As shown, the method MT1 may include the steps ST0, ST1, ST2, ST3, ST4, and ST5. The method MT1 may not include the step ST0. The method MT1 may not include the step ST3. The method MT1 may not include the step ST5.

[0048] Process ST0 to process ST5 can be performed sequentially. Process ST1 can also be performed simultaneously with process ST0. At least two of process ST1, process ST2 and process ST4 can also be performed simultaneously. For example, process ST4 can be performed after process ST1 and process ST2 are performed simultaneously. Process ST2 and process ST4 can also be performed simultaneously after process ST1 is performed. Process ST1, process ST2 and process ST4 can also be performed simultaneously. Process ST4 and process ST1 can also be performed simultaneously after process ST2 is performed. That is, process ST4 can also be performed simultaneously with process ST1 after process ST4. In process ST0 to process ST5, substrate W can be processed in situ. Below, process ST0 to process ST5 are described.

[0049] (Process ST0)

[0050] like Figure 5 As shown, the process gas can be used to Figure 4 The substrate W is etched. In step ST0, plasma generated from the processing gas may be used. A recess R1 corresponding to the opening OP of the mask MK is formed on the etching target film RE by etching. A plurality of recesses R1 may be formed on the etching target film RE. The recess R1 has side walls R1s and a bottom R1b. The recess R1 may also be an opening. The recess R1 is, for example, a hole or a groove. The recess R1 may be formed by plasma etching using the plasma processing device 1 in the same manner as in step ST4 described later. Without performing step ST0, the substrate W having the recess R1 may be formed by plasma etching using the plasma processing device 1. Figure 5The substrate W is placed on the substrate support 11 in the plasma processing chamber 10 .

[0051] (Process ST1)

[0052] like Figure 6 As shown, the first layer F1 is formed on the side wall R1s of the recess R1 of the substrate W using the first process gas. In step ST1, the first plasma P1 generated from the first process gas may be used. In step ST1, the substrate W may be exposed to the first process gas or the first plasma P1. The first process gas or the first plasma P1 may form the first layer F1 on the side wall R1s of the recess R1 of the substrate W. The first plasma P1 may be generated by the plasma generating unit 12 of the plasma processing apparatus 1. The first process gas may be supplied from the gas supply unit 20 of the plasma processing apparatus 1 into the plasma processing chamber 10.

[0053] The first process gas may contain at least one selected from the group consisting of hydrogen atoms and nitrogen atoms. The first process gas may also contain at least one selected from the group consisting of hydrogen-containing gas, nitrogen-containing gas, oxygen-containing gas, and fluorine-containing gas.

[0054] The hydrogen-containing gas may include a gas selected from the group consisting of H 2 Gas, H 2 O gas, hydrocarbon gas, hydrofluorocarbon gas, NH 3 gas, HF gas and ammonia (NH 3 )At least one of the group consisting of gases.

[0055] The nitrogen-containing gas may include a gas selected from the group consisting of N 2 Gas, ammonia (NH 3 ) Gas, NF 3 Gas, NO gas and NO 2 At least one of the group consisting of gases.

[0056] The oxygen-containing gas may include a 2 Gas, H 2 O gas, CO gas, CO 2 Gas, NO Gas, NO 2 Gas and SO 2 At least one of the group consisting of gases.

[0057] The fluorine-containing gas may include a gas selected from HF gas, BF 3 Gas, fluorocarbon gas, hydrofluorocarbon gas, PF 3 Gas, PF 5 Gas, NF 3 Gas, SF 6 Gas, F 2 Gas, CIF 3Gas, IF 7 Gas, MoF 6 Gas and WF 6 At least one of the group consisting of gases. The fluorocarbon gas may include a gas selected from C 4 F 6 Gas, C 4 F 8 Gas, C 3 F 8 Gas and CF 4 At least one of the group consisting of gases. The hydrofluorocarbon gas may include CHF 3 Gas, CH 2 F 2 Gas, CH 3 F gas, C 3 H 2 F 4 Gas and C 4 H 2 F 6 At least one of the group consisting of gases.

[0058] When the etching target film RE contains nitrogen, the first processing gas may contain hydrogen atoms instead of nitrogen atoms. In this case, nitrogen atoms from the etching target film RE and hydrogen atoms from the first processing gas are contained in the first layer F1. When the etching target film RE does not contain nitrogen, the first processing gas may contain hydrogen atoms and nitrogen atoms. In this case, hydrogen atoms and nitrogen atoms from the first processing gas are contained in the first layer F1. When the etching target film RE contains hydrogen atoms, the first processing gas may contain nitrogen atoms instead of hydrogen atoms. In this case, hydrogen atoms from the etching target film RE and nitrogen atoms from the first processing gas are contained in the first layer F1. When the etching target film RE contains oxygen atoms, the first processing gas may contain hydrogen atoms and nitrogen atoms. In this case, hydrogen atoms and nitrogen atoms from the first processing gas are contained in the first layer F1.

[0059] The first layer F1 contains nitrogen atoms and hydrogen atoms. The first layer F1 may also contain ammonia (NH 3 ) or have an amino group (-NH 2 ). The first layer F1 is, for example, an ammonia adsorption layer. The first layer F1 is formed as a result of the interaction (for example, adsorption or chemical reaction) between the first plasma P1 and the etching target film RE. Due to the aspect ratio of the recess R1, it is more difficult for the first plasma P1 to reach the bottom R1b than the sidewall R1s of the recess R1, so the first layer F1 is not easily formed at the bottom R1b of the recess R1.

[0060] Since ammonia (NH 3 ) gas has a high reactivity, so the first processing gas contains ammonia (NH 3) gas, the first plasma P1 may not be generated. Even in this case, it is expected that a plasma containing ammonia (NH 3 ) or have an amino group (-NH 2 ) of the compound of the first layer F1.

[0061] In step ST1, the temperature of the substrate W may be 60°C or lower, 55°C or lower, or 30°C or lower. In this case, the temperature of the substrate support 11 for supporting the substrate W may be 60°C or lower, 30°C or lower, 0°C or lower, -30°C or lower, or -70°C or lower. In one example, the temperature of the substrate support 11 for supporting the substrate W may be -30°C or higher and 0°C or lower.

[0062] In step ST1 , the recess R1 may be etched. In this case, since the bottom R1 b of the recess R1 is etched, the first layer F1 is less likely to be formed on the bottom R1 b of the recess R1 .

[0063] (Process ST2)

[0064] like Figure 7 As shown, the second layer F2 is formed from the first layer F1 using the second process gas. The second process gas may be the same as the first process gas or may be different from the first process gas. In step ST2, a second plasma P2 generated from the second process gas may be used. In step ST2, the substrate W may also be exposed to the second process gas or the second plasma P2. The second process gas or the second plasma P2 can form the second layer F2 from the first layer F1. The second plasma P2 may be generated by the plasma generating unit 12 of the plasma processing apparatus 1. The second process gas may be supplied from the gas supply unit 20 of the plasma processing apparatus 1 into the plasma processing chamber 10.

[0065] The second processing gas includes a phosphorus-containing gas. The phosphorus-containing gas may also include a halogen. The phosphorus-containing gas may also include at least one selected from the group consisting of phosphorus hydride, phosphorus fluoride, phosphorus halides other than fluorine, and phosphoryl halides. The phosphorus-containing gas may also include a PH 3 PF 3 PF 5 、PCl 3 , PBr 3 POF 3 POCl 3 and POBr 3 At least one of the group consisting of.

[0066] The second processing gas may further include at least one selected from the group consisting of a halogen-containing gas, an oxygen-containing gas, and a hydrogen-containing gas. The halogen-containing gas may also be a fluorine-containing gas. The halogen-containing gas may also include a polar halogen compound. The halogen compound may be a hydrogen halide (HX: X is any one of F, Cl, Br, and I), or a halogenated alkane (C n H 2n+ 1 X: X is any one of F, Cl, Br and I, and n is an integer greater than or equal to 1). The alkyl halide is, for example, CH 3 Br(Methyl bromide) or C 2 H 5 Cl (ethyl chloride), etc. The second processing gas may not contain fluorocarbon gas. Examples of oxygen-containing gas, hydrogen-containing gas and fluorine-containing gas that may be contained in the second processing gas are the same as those of oxygen-containing gas, hydrogen-containing gas and fluorine-containing gas that may be contained in the first processing gas.

[0067] The second layer F2 may also contain a compound selected from ammonium hexafluorophosphate (NH 4 PF 6 ), ammonium phosphate (NH 4 ) 3 PO 4 ), diammonium hydrogen phosphate ((NH 4 ) 2 HPO 4 ) and diammonium phosphate (NH 4 H 2 PO 4 ). The second layer F2 may be formed by reacting the phosphorus-containing gas with the first layer F1. The second layer F2 may function as a protective layer against etching in the later-described step ST4. Since the second layer F2 is formed from the first layer F1, it is not easily formed on the bottom R1b of the recess R1. The second layer F2 may further contain ammonium halide (NH 4 X: X is any one of F, Cl, Br and I) or halogenated amine (NH 2 X: X is any one of F, Cl, Br and I).

[0068] In step ST2 , an example of the temperature of the substrate W may be the same as the example of the temperature of the substrate W in step ST1 . In this case, an example of the temperature of the substrate support 11 for supporting the substrate W may be the same as the example of the temperature of the substrate W in step ST1 .

[0069] After step ST2 , the plasma processing chamber 10 may be purged. The purging gas may be supplied from the gas supply unit 20 of the plasma processing apparatus 1 into the plasma processing chamber 10 .

[0070] (Process ST3)

[0071] like Figure 3 As shown, step ST1 and step ST2 may be repeated. In step ST3, it may be determined whether the number of implementations of step ST1 and step ST2 has reached a predetermined value. The determination may be made by the control unit 2 of the substrate processing apparatus. When the number of implementations of step ST1 and step ST2 has not reached a predetermined value, the process returns to step ST1 and repeats step ST1 and step ST2. When the number of implementations of step ST1 and step ST2 has reached a predetermined value, step ST3 is terminated and step ST4 is performed. In this way, method MT1 may further include a step of repeating step ST1 and step ST2 before step ST4.

[0072] (Process ST4)

[0073] like Figure 8 As shown, the recess R1 is etched using a third process gas. In step ST4, the bottom R1b of the recess R1 may also be etched. The third process gas may be the same as or different from the first process gas. The third process gas may be the same as or different from the second process gas. In step ST4, a third plasma P3 generated from the third process gas may also be used. In step ST4, the substrate W may also be exposed to the third process gas or the third plasma P3. The third process gas or the third plasma P3 may etch the recess R1. The third plasma P3 may be generated by the plasma generating unit 12 of the plasma processing apparatus 1. The third process gas may be supplied from the gas supply unit 20 of the plasma processing apparatus 1 to the plasma processing chamber 10.

[0074] In step ST4 , an example of the temperature of the substrate W may be the same as the example of the temperature of the substrate W in step ST1 . In this case, an example of the temperature of the substrate support 11 for supporting the substrate W may be the same as the example of the temperature of the substrate W in step ST1 .

[0075] In step ST4, bias power may be applied to the substrate support 11 for supporting the substrate W. The bias power may be applied by Figure 2 The bias power is applied by the power supply 30. The etching speed of the bottom R1b of the recess R1 is increased by the bias power.

[0076] (Process ST5)

[0077] like Figure 3 As shown in FIG. 1 , steps ST1 to ST4 may be repeated. In step ST5, as shown in FIG. Fig. 9As shown, it is also possible to determine whether the depth DP of the recess R1 has reached a threshold value. The depth DP of the recess R1 can be monitored, for example, by an endpoint monitor or the like. The determination can be made by the control unit 2 of the substrate processing apparatus. When the depth DP of the recess R1 reaches the threshold value, the method MT1 is terminated. When the depth DP of the recess R1 does not reach the threshold value, the process returns to step ST1 and repeats steps ST1 to ST4. In step ST5, it is also possible to determine whether the number of repetitions of steps ST1 to ST4 has reached a threshold value. In this way, in the method MT1, a process of repeating steps ST1, ST2, and ST4 may be further included after step ST4.

[0078] When step ST4 is performed simultaneously with step ST1 after step ST4, the third plasma P3 also serves as the first plasma P1. As a result, etching of the recess R1 and formation of the first layer F1 are performed simultaneously.

[0079] After the method MT1 is completed, the depth DP of the recess R1 may be greater than 3 μm, and the aspect ratio of the recess R1 (the depth DP of the recess R1 relative to the width WD) may be greater than 30. After the method MT1 is completed, the ratio (TH / DP) of the thickness TH of the mask MK to the depth DP of the recess R1 may be greater than 1 / 5.

[0080] According to the method MT1 of the embodiment, in step ST4, since the second layer F2 is formed on the side wall R1s of the recess R1, etching of the side wall R1s of the recess R1 can be suppressed. Therefore, shape defects (bending) of the side wall R1s of the recess R1 during etching can be suppressed.

[0081] In addition, the second layer F2 formed on the side wall R1s of the recess R1 can suppress the etching of the side wall R1s of the recess R1, and the bottom R1b of the recess R1 can be etched. However, the etching is not limited to the bottom R1b of the recess R1. For example, Figure 8As shown, the side wall R1s of the recess R1 where the second layer F2 is not formed can also be newly exposed by etching the bottom R1b of the recess R1, and the exposed side wall R1s of the recess R1 can be etched. In addition, there is a case where if the aspect ratio of the recess R1 is high, the second layer F2 is formed in the upper area of ​​the side wall R1s of the recess R1, which is a part where shape defects (bending) are likely to occur, rather than in the lower area. In this case, not only the bottom R1b of the recess R1 can be etched, but also the side wall R1s of the recess R1 where the second layer F2 is not formed can be etched. If the aspect ratio of the recess R1 is high, it is easy to form a tapered shape in which the width of the recess R1 decreases from the upper end of the recess R1 toward the bottom R1b. However, by etching the side wall R1s of the recess R1 where the second layer F2 is not formed, the width of the recess R1 in the bottom R1b can be expanded.

[0082] According to the method MT1, it is possible to suppress the first layer F1 and the second layer F2 from closing the opening OP of the mask MK.

[0083] Various exemplary embodiments have been described above, but the present invention is not limited to the exemplary embodiments described above, and various additions, omissions, substitutions, and changes may be made. Furthermore, elements in different embodiments may be combined to form other embodiments.

[0084] Various experiments performed to evaluate the method MT1 are described below. The experiments described below do not limit the present invention.

[0085] (First Experiment)

[0086] In the first experiment, a substrate W having a laminated film formed by alternately laminating silicon nitride films and silicon oxide films and a mask MK on the laminated film was prepared. Then, the above-mentioned method MT1 was performed on the substrate W using the above-mentioned plasma processing system. Steps ST1, ST2, and ST4 were performed simultaneously. Steps ST0, ST3, and ST5 were not performed. In steps ST1, ST2, and ST4, a gas containing hydrogen and PF was used. 3 Plasma generated by the processing gas of the gas In step ST1, step ST2, and step ST4, the temperature of the substrate W is 30°C.

[0087] (Experimental results)

[0088] The components of the side wall of the recess R1 of the substrate W subjected to the method MT1 in the first experiment were analyzed by time-of-flight secondary ion mass spectrometry (TOF-SIMS), and as a result, ammonium hexafluorophosphate and phosphate were detected.

[0089] Here, various exemplary embodiments included in the present invention are described in the following [E1] to [E23].

[0090] [E1]

[0091] A method for processing a substrate including an etching target film and a mask provided on the etching target film and having an opening, and comprising the following steps:

[0092] (a) forming a first layer containing nitrogen atoms and hydrogen atoms on a side wall of a recessed portion formed on the etching target film corresponding to the opening using a first processing gas;

[0093] (b) forming a second layer from the first layer using a second process gas including a phosphorus-containing gas; and

[0094] (c) Etching the concave portion using a third process gas.

[0095] According to the method [E1], in (c), since the second layer is formed on the side wall of the recessed portion, etching of the side wall of the recessed portion can be suppressed. Therefore, shape defects of the side wall of the recessed portion during etching can be suppressed.

[0096] [E2]

[0097] The method according to [E2], wherein:

[0098] In the above (a), using the first plasma generated from the first processing gas,

[0099] In the above (b), using the second plasma generated from the second process gas,

[0100] In the above (c), a third plasma generated from the third process gas is used.

[0101] [E3]

[0102] The method according to [E1] or [E2], wherein:

[0103] The method further includes repeating the steps (a) and (b) before the step (c).

[0104] [E4]

[0105] The method according to any one of [E1] to [E3], wherein

[0106] After the step (c), the method further includes repeating the steps (a), (b), and (c).

[0107] In this case, a deeper recess can be formed.

[0108] [E5]

[0109] The method according to [E4], wherein

[0110] The (c) is performed simultaneously with the (a) after the (c).

[0111] In this case, the first layer can be formed on the side wall of the recessed portion while etching the recessed portion.

[0112] [E6]

[0113] The method according to any one of [E1] to [E5], wherein

[0114] The (b) is performed after the (a),

[0115] The (c) is performed after the (b).

[0116] [E7]

[0117] The method according to [E1] or [E2], wherein:

[0118] After (a) and (b) are performed simultaneously, (c) is performed.

[0119] [E8]

[0120] The method according to [E1] or [E2], wherein:

[0121] After performing the step (a), the steps (b) and (c) are performed simultaneously.

[0122] [E9]

[0123] The method according to [E1] or [E2], wherein:

[0124] The (a), (b) and (c) are performed simultaneously.

[0125] [E10]

[0126] The method according to any one of [E1] to [E8], wherein

[0127] The etching target film includes a silicon-containing film.

[0128] [E11]

[0129] The method according to [E10], wherein

[0130] The silicon-containing film contains nitrogen,

[0131] The first processing gas contains hydrogen atoms.

[0132] [E12]

[0133] The method according to [E10] or [E11], wherein:

[0134] The silicon-containing film does not contain nitrogen,

[0135] The first processing gas includes hydrogen atoms and nitrogen atoms.

[0136] [E13]

[0137] The method according to any one of [E1] to [E12], wherein

[0138] The etching target film includes a film containing hydrogen,

[0139] The first processing gas contains nitrogen atoms.

[0140] [E14]

[0141] The method according to any one of [E1] to [E13], wherein

[0142] The etching target film includes a film containing oxygen,

[0143] The first processing gas includes hydrogen atoms and nitrogen atoms.

[0144] [E15]

[0145] The method according to any one of [E1] to [E14], wherein

[0146] The second process gas further includes a halogen-containing gas.

[0147] [E16]

[0148] The method according to [E15], wherein

[0149] The halogen-containing gas contains a polar halogen compound.

[0150] In this case, the reactivity of the halogen-containing gas to the first layer becomes high.

[0151] [E17]

[0152] The method according to any one of [E1] to [E16], wherein

[0153] The phosphorus-containing gas comprises a gas selected from the group consisting of PH 3 PF 3 PF 5 、PCl 3 , PBr 3 POF 3 POCl 3and POBr 3 At least one of the group consisting of.

[0154] [E18]

[0155] The method according to any one of [E1] to [E17], wherein

[0156] The first layer contains ammonia or a compound having an amino group.

[0157] [E19]

[0158] The method according to any one of [E1] to [E18], wherein

[0159] The second layer includes at least one selected from the group consisting of ammonium hexafluorophosphate, ammonium phosphate, diammonium hydrogen phosphate, and ammonium dihydrogen phosphate.

[0160] [E20]

[0161] The method according to any one of [E1] to [E19], wherein

[0162] In the above (c), bias power is applied to a substrate supporting portion for supporting the substrate.

[0163] In this case, the recessed portion can be selectively etched.

[0164] [E21]

[0165] The method according to any one of [E1] to [E20], wherein

[0166] In the above (b), the temperature of the substrate is 60° C. or lower.

[0167] [E22]

[0168] A substrate processing device comprising:

[0169] Cavity;

[0170] A substrate support portion for supporting a substrate in the cavity, wherein the substrate includes an etching target film and a mask provided on the etching target film and having an opening;

[0171] a gas supply unit configured to supply a first process gas, a second process gas, and a third process gas into the chamber, wherein the second process gas includes a phosphorus-containing gas; and

[0172] Control Department,

[0173] The control unit is configured to control the gas supply unit in the following manner:

[0174] (a) forming a first layer containing nitrogen atoms and hydrogen atoms on a side wall of a recessed portion formed on the etching target film corresponding to the opening using the first processing gas;

[0175] (b) forming a second layer from the first layer using the second process gas; and

[0176] (c) etching the concave portion using the third process gas.

[0177] [E23]

[0178] A method for processing a substrate including an etching target film and a mask provided on the etching target film and having an opening, and comprising the following steps:

[0179] (a) exposing the substrate to a first processing gas, wherein the first processing gas is capable of forming a first layer containing nitrogen atoms and hydrogen atoms on a side wall of a recessed portion formed on the etching target film corresponding to the opening;

[0180] (b) exposing the substrate to a second process gas including a phosphorus-containing gas, wherein the second process gas is capable of forming a second layer from the first layer; and

[0181] (c) exposing the substrate to a third process gas, wherein the third process gas is capable of etching the recessed portion.

[0182] It can be understood from the above description that various embodiments of the present invention are described in this specification for the purpose of explanation, and various changes can be made without departing from the scope and spirit of the present invention. Therefore, the various embodiments disclosed in this specification are not intended to be limiting, and the true scope and spirit are represented by the scope of the attached claims.

[0183] Explanation of symbols

[0184] 2-control unit, 10-plasma processing chamber, 11-substrate supporting unit, 20-gas supply unit, F1-first layer, F2-second layer, MK-mask, MT1-method, OP-opening, R1-recess, R1s-side wall, RE-etching object film, W-substrate.

Claims

1. A method for processing a substrate having an etching target film and a mask provided on the etching target film and having an opening, comprising the following steps: (a) forming a first layer containing nitrogen atoms and hydrogen atoms on a side wall of a recessed portion formed on the etching target film corresponding to the opening using a first processing gas; (b) forming a second layer from the first layer using a second process gas including a phosphorus-containing gas; and (c) Etching the concave portion using a third process gas.

2. The method according to claim 1, wherein: In the above (a), using the first plasma generated from the first processing gas, In the above (b), using the second plasma generated from the second process gas, In the above (c), a third plasma generated from the third process gas is used.

3. The method according to claim 1 or 2, wherein: The method further includes repeating the steps (a) and (b) before the step (c).

4. The method according to claim 1 or 2, wherein: After the step (c), the method further includes repeating the steps (a), (b), and (c).

5. The method according to claim 4, wherein: The (c) is performed simultaneously with the (a) after the (c).

6. The method according to claim 1 or 2, wherein: The (b) is performed after the (a), The (c) is performed after the (b).

7. The method according to claim 1 or 2, wherein: The (a), (b) and (c) are performed simultaneously.

8. The method according to claim 1 or 2, wherein: The etching target film includes a silicon-containing film.

9. The method according to claim 8, wherein: The silicon-containing film contains nitrogen, The first processing gas contains hydrogen atoms.

10. The method according to claim 8, wherein: The silicon-containing film does not contain nitrogen, The first processing gas includes hydrogen atoms and nitrogen atoms.

11. The method according to claim 1 or 2, wherein: The etching target film includes a film containing hydrogen, The first processing gas contains nitrogen atoms.

12. The method according to claim 1 or 2, wherein: The etching target film includes a film containing oxygen, The first processing gas includes hydrogen atoms and nitrogen atoms.

13. The method according to claim 1 or 2, wherein: The second process gas further includes a halogen-containing gas.

14. The method according to claim 13, wherein: The halogen-containing gas contains a polar halogen compound.

15. The method according to claim 1 or 2, wherein: The phosphorus-containing gas includes at least one selected from the group consisting of PH3, PF3, PF5, PCl3, PBr3, POF3, POCl3 and POBr3.

16. The method according to claim 1 or 2, wherein: The first layer contains ammonia or a compound having an amino group.

17. The method according to claim 1 or 2, wherein: The second layer includes at least one selected from the group consisting of ammonium hexafluorophosphate, ammonium phosphate, diammonium hydrogen phosphate, and ammonium dihydrogen phosphate.

18. The method according to claim 1 or 2, wherein: In the above (c), bias power is applied to a substrate supporting portion for supporting the substrate.

19. The method according to claim 1 or 2, wherein: In the above (b), the temperature of the substrate is 60° C. or lower.

20. A substrate processing device comprising: Cavity; A substrate support portion for supporting a substrate in the cavity, wherein the substrate includes an etching target film and a mask provided on the etching target film and having an opening; a gas supply unit configured to supply a first process gas, a second process gas, and a third process gas into the chamber, wherein the second process gas includes a phosphorus-containing gas; and Control Department, in, The control unit is configured to control the gas supply unit in the following manner: (a) forming a first layer containing nitrogen atoms and hydrogen atoms on a side wall of a recessed portion formed on the etching target film corresponding to the opening using the first processing gas; (b) forming a second layer from the first layer using the second process gas; and (c) etching the concave portion using the third process gas.

21. A method for processing a substrate having an etching target film and a mask provided on the etching target film and having an opening, the method comprising the following steps: (a) exposing the substrate to a first processing gas, wherein the first processing gas is capable of forming a first layer containing nitrogen atoms and hydrogen atoms on a side wall of a recessed portion formed on the etching target film corresponding to the opening; (b) exposing the substrate to a second process gas including a phosphorus-containing gas, wherein the second process gas is capable of forming a second layer from the first layer; and (c) exposing the substrate to a third process gas, wherein the third process gas is capable of etching the recessed portion.

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