Etching method and plasma processing system

Abstract

To provide a technology that increases the selectivity for a mask.SOLUTION: An etching method that is performed in a plasma treatment device having a chamber includes a step (a) of providing a substrate in a chamber having a silicon-containing film and a mask on the silicon-containing film, a step (b) of generating plasma from processing gas including HF gas and PClaFb (a and b are each an integer greater than or equal to 1) gas or PCcHdFe (c is an integer greater than or equal to 0, and d and e are integers of 1 or more) gas in the chamber, and etching a silicon-containing film.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] Exemplary embodiments of the present disclosure relate to an etching method and a plasma processing system. [Background technology]

[0002] Patent Document 1 discloses a technique for etching a silicon-containing film. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-39310 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides plasma processing techniques that increase selectivity to a mask. [Means for solving the problem]

[0005] In one exemplary embodiment of the present disclosure, an etching method is carried out in a plasma processing apparatus having a chamber, the method comprising: (a) providing a substrate having a silicon-containing film and a mask on the silicon-containing film in the chamber; and (b) etching a silicon-containing film in the chamber using HF gas and a PCl gas. a F b (a and b are integers of 1 or more) Gas or PC c H d F e (d and e are each an integer of 1 or more, and c is an integer of 0 or more) gas, and generating plasma from a process gas containing the gas to etch the silicon-containing film. Effect of the Invention

[0006] According to one exemplary embodiment of the present disclosure, a plasma processing technique that increases the selectivity to a mask can be provided. [Brief description of the drawings]

[0007] [Figure 1] 1 illustrates a schematic diagram of an exemplary plasma processing system. [Diagram 2] 3 is a flowchart showing the present processing method. [Diagram 3] 2 is a diagram illustrating an example of a cross-sectional structure of a substrate W provided in step ST1. FIG. [Figure 4] 10 is a diagram illustrating an example of a cross-sectional structure of a substrate W during processing in step ST2. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Each embodiment of the present disclosure will be described below.

[0009] In one exemplary embodiment, an etching method is performed in a plasma processing apparatus having a chamber, the method comprising the steps of: (a) providing a substrate having a silicon-containing film and a mask on the silicon-containing film in the chamber; (b) etching a silicon-containing film in the chamber using HF gas and a PCl a F b (a is an integer of 1 or more, b is an integer of 0 or more, and the sum of a and b is an integer of 5 or less) Gas or PC c H d F e (c is an integer of 0 to 5, and d and e are each an integer of 1 to 9) gas, and generating plasma from the process gas containing the gas to etch the silicon-containing film.

[0010] In one exemplary embodiment, PCl a F b In the gas, a and b are each an integer of 1 or more.

[0011] In one exemplary embodiment, PCl a Fb The gas includes at least one gas selected from the group consisting of PClF2 gas, PCl2F gas, and PCl2F3 gas.

[0012] In one exemplary embodiment, a PC c H d F e The gas includes at least one gas selected from the group consisting of PF2CH3 gas, PF(CH3)2 gas, PH2CF3 gas, PH(CF3)2 gas, PCH3(CF3)2 gas, PH2F gas, and PF3(CH3)2 gas.

[0013] In one exemplary embodiment, the process gas supplied into the chamber in (b) has a flow rate of HF gas, excluding an inert gas.

[0014] In one exemplary embodiment, the flow rate of the HF gas is 50% by volume or more of the total flow rate of the process gas excluding the inert gas.

[0015] In one exemplary embodiment, PCl a F b Gas or PC c H d F e The flow rate of the gas is 20% by volume or less of the total flow rate of the processing gas excluding the inert gas.

[0016] In one exemplary embodiment, the process gas is f F g (wherein f and g are each an integer greater than or equal to 1) further comprising a gas.

[0017] In one exemplary embodiment, the process gas is h H i F j (wherein h, i and j are each an integer of 1 or greater) further comprising a gas.

[0018] In one exemplary embodiment, the process gas further includes WF6 gas or BCl3 gas.

[0019] In one exemplary embodiment, in (b), the temperature of the substrate support that supports the substrate is set to 0° C. or lower.

[0020] In one exemplary embodiment, the mask is a carbon-containing or metal-containing film.

[0021] In one exemplary embodiment, there is provided an etching method performed in a plasma processing apparatus having a chamber, the etching method comprising: (a) providing a substrate having a silicon-containing film and a mask on the silicon-containing film in the chamber; and (b) generating plasma in the chamber from a process gas including a gas containing H (hydrogen) and F (fluorine) and a phosphorus-containing gas to etch the substrate, the phosphorus-containing gas being a gas including P (phosphorus), F (fluorine) and a halogen other than F (fluorine) in its molecular structure, a gas including P (phosphorus), F (fluorine), C (carbon) and H (hydrogen) in its molecular structure, or a gas including P (phosphorus), F (fluorine) and H (hydrogen) in its molecular structure.

[0022] In one exemplary embodiment, the H and F containing gas is HF gas or C h H i F j (h, i, and j are each an integer of 1 or more) gas.

[0023] In one exemplary embodiment, the process gas further comprises a carbon-containing gas.

[0024] In one exemplary embodiment, an etching method performed in a plasma processing apparatus having a chamber includes the steps of: (a) providing a substrate having a silicon-containing film and a mask on the silicon-containing film in the chamber; (b) extracting from a process gas a HF species and a PCl a F b (a is an integer of 1 or more, b is an integer of 0 or more, and the sum of a and b is an integer of 5 or less) c H d F e(c is an integer of 0 to 5, and d and e are each an integer of 1 to 9) to generate plasma containing the species, and etching the silicon-containing film.

[0025] In one exemplary embodiment, the HF species is at least one gas selected from the group consisting of HF gas and a hydrofluorocarbon gas.

[0026] In one exemplary embodiment, the HF species is a hydrofluorocarbon gas having two or more carbon atoms.

[0027] In one exemplary embodiment, the HF species is at least one gas selected from the group consisting of HF gas, CH2F2 gas, C3H2F4 gas, C3H2F6 gas, and C4H2F6 gas.

[0028] In one exemplary embodiment, a plasma processing system includes a chamber, a process gas supply, and a controller, the controller configured to: (a) provide a substrate having a silicon-containing film and a mask on the silicon-containing film in the chamber; (b) supply HF gas and PCl gas to the process gas supply; a F b (a and b are each an integer of 1 or greater) Gas or PC c H d F e (c is an integer equal to or greater than 0, and d and e are each an integer equal to or greater than 1) gas into a chamber to generate plasma and etch a silicon-containing film.

[0029] <Example of plasma processing system configuration> An example of the configuration of a plasma processing system will be described below. Fig. 1 is a diagram for explaining an example of the configuration of a capacitively coupled plasma processing apparatus.

[0030] The plasma processing system includes a capacitively coupled plasma processing device 1 and a controller 2. The capacitively coupled plasma processing device 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply 30, and an exhaust system 40. The plasma processing device 1 also includes a substrate support 11 and a gas inlet. The gas inlet is configured to introduce at least one processing gas into the plasma processing chamber 10. The gas inlet includes a shower head 13. The substrate support 11 is disposed in the plasma processing chamber 10. The shower head 13 is disposed above the substrate support 11. In one embodiment, the shower head 13 forms at least a part of a ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the shower head 13, a sidewall 10a of the plasma processing chamber 10, and the substrate support 11. The plasma processing chamber 10 has at least one gas inlet for supplying at least one processing gas to the plasma processing space 10s and at least one gas outlet for exhausting gas from the plasma processing space. The plasma processing chamber 10 is grounded. The showerhead 13 and the substrate support 11 are electrically isolated from the housing of the plasma processing chamber 10.

[0031] The substrate support 11 includes a main body 111 and a ring assembly 112. The main body 111 has a central region 111a for supporting the substrate W and an annular region 111b for supporting the ring assembly 112. A wafer is an example of the substrate W. The annular region 111b of the main body 111 surrounds the central region 111a of the main body 111 in a plan view. The substrate W is disposed on the central region 111a of the main body 111, and the ring assembly 112 is disposed on the annular region 111b of the main body 111 so as to surround the substrate W on the central region 111a of the main body 111. Therefore, the central region 111a is also called a substrate support surface for supporting the substrate W, and the annular region 111b is also called a ring support surface for supporting the ring assembly 112.

[0032] 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 may function as a lower electrode. The electrostatic chuck 1111 is disposed on the base 1110. The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic electrode 1111b disposed within the ceramic member 1111a. The ceramic member 1111a has a central region 111a. In one embodiment, the ceramic member 1111a also has an annular region 111b. Note that other members surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member, may have the annular region 111b. In this case, the ring assembly 112 may be disposed on the annular electrostatic chuck or the annular insulating member, or may be disposed on both the electrostatic chuck 1111 and the annular insulating member. Also, at least one RF / DC electrode coupled to a radio frequency (RF) power source 31 and / or a direct current (DC) power source 32 described later may be disposed in the ceramic member 1111a. In this case, the at least one RF / DC electrode functions as a lower electrode. When a bias RF signal and / or a DC signal described later is supplied to the at least one RF / DC electrode, the RF / DC electrode is also called a bias electrode. Note that the conductive member of the base 1110 and the at least one RF / DC electrode may function as a plurality of lower electrodes. Also, the electrostatic electrode 1111b may function as a lower electrode. Thus, the substrate support 11 includes at least one lower electrode.

[0033] The ring assembly 112 includes one or more annular members. In one embodiment, the one or more annular members include one or more edge rings and at least one cover ring. The edge rings are formed of a conductive or insulating material, and the cover rings are formed of an insulating material.

[0034] The substrate support 11 may also include a temperature adjustment module configured to adjust at least one of the electrostatic chuck 1111, the ring assembly 112, and the substrate to a target temperature. The temperature adjustment module may include a heater, a heat transfer medium, a flow passage 1110a, or a combination thereof. A heat transfer fluid such as a brine or a gas flows through the flow passage 1110a. In one embodiment, the flow passage 1110a is formed in the base 1110, and one or more heaters are disposed in the ceramic member 1111a of the electrostatic chuck 1111. The substrate support 11 may also include a heat transfer gas supply configured to supply a heat transfer gas to a gap between the back surface of the substrate W and the central region 111a.

[0035] The shower head 13 is configured to introduce at least one processing gas from the gas supply unit 20 into the plasma processing space 10s. The shower head 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and multiple gas inlets 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 from the multiple gas inlets 13c. The shower head 13 also includes at least one upper electrode. Note that the gas introduction unit may include, in addition to the shower head 13, one or more side gas injectors (SGIs) attached to one or more openings formed in the sidewall 10a.

[0036] The gas supply 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply 20 is configured to supply at least one process gas from a respective gas source 21 through a respective flow controller 22 to the showerhead 13. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, the gas supply 20 may include one or more flow modulation devices to modulate or pulse a flow rate of the at least one process gas.

[0037] The power source 30 includes an RF power source 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power source 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 causes a plasma to be formed from at least one processing gas supplied to the plasma processing space 10s. Thus, the RF power source 31 can function as at least a part of a plasma generating unit configured to generate a plasma from one or more processing gases in the plasma processing chamber 10. In addition, a bias potential is generated on the substrate W by supplying a bias RF signal to the at least one lower electrode, and ion components in the formed plasma can be attracted to the substrate W.

[0038] In one embodiment, the RF power supply 31 includes a first RF generating unit 31a and a second RF generating unit 31b. The first RF generating unit 31a is coupled to at least one lower electrode and / or at least one upper electrode via at least one impedance matching circuit, and is configured to generate a source RF signal (source RF power) for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 10 MHz to 150 MHz. In one embodiment, the first RF generating unit 31a may be configured to generate 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.

[0039] The second RF generating unit 31b is coupled to at least one lower electrode via at least one impedance matching circuit and configured to generate a bias RF signal (bias RF power). The frequency of the bias RF signal may be the same as or different from the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency lower than the frequency of the source RF signal. In one embodiment, the bias RF signal has a 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. Also, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0040] The power supply 30 may also include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generator 32a and a second DC generator 32b. In one embodiment, the first DC generator 32a is connected to at least one lower electrode and configured to generate a first DC signal. The generated first bias DC signal is applied to the at least one lower electrode. In one embodiment, the second DC generator 32b is connected to at least one upper electrode and configured to generate a second DC signal. The generated second DC signal is applied to the at least one upper electrode.

[0041] In various embodiments, at least one of the first and second DC signals may be pulsed. In this case, a sequence of voltage pulses is applied to at least one lower electrode and / or at least one upper electrode. The voltage pulses may have a rectangular, trapezoidal, triangular or combination thereof pulse waveform. In one embodiment, a waveform generator for generating a sequence of voltage pulses from the DC signal is connected between the first DC generator 32a and at least one lower electrode. Thus, the first DC generator 32a and the waveform generator constitute a voltage pulse generator. When the second DC generator 32b and the waveform generator constitute a voltage pulse generator, the voltage pulse generator is connected to at least one upper electrode. The voltage pulses 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 in one period. The first and second DC generating units 32a, 32b may be provided in addition to the RF power supply 31, or the first DC generating unit 32a may be provided in place of the second RF generating unit 31b.

[0042] The exhaust system 40 may be connected to, for example, a gas exhaust port 10e provided at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure in the plasma processing space 10s is adjusted by the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0043] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to execute various steps described in the present disclosure. The control unit 2 may be configured to control each element of the plasma processing apparatus 1 to execute various steps described herein. In one embodiment, a part or all of the control unit 2 may be included in the plasma processing apparatus 1. The control unit 2 may include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The control unit 2 is realized, for example, by a computer 2a. The processing unit 2a1 may be configured to perform various control operations by reading a program from the storage unit 2a2 and executing the read program. This program may be stored in the storage unit 2a2 in advance, or may be acquired via a medium when necessary. The acquired program is stored in the storage unit 2a2 and is read from the storage unit 2a2 by the processing unit 2a1 and executed. The medium may be various storage media readable by the computer 2a, or may be a communication line connected to the communication interface 2a3. The processing unit 2a1 may be a CPU (Central Processing Unit). The storage unit 2a2 may include a random access memory (RAM), a read only memory (ROM), a hard disk drive (HDD), a solid state drive (SSD), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing apparatus 1 via a communication line such as a local area network (LAN).

[0044] Fig. 2 is a flowchart showing an etching method (hereinafter also referred to as "this processing method") according to an example embodiment. As shown in Fig. 2, this processing method includes a step ST1 of providing a substrate, and a step ST2 of etching a silicon-containing film. The processing in each step may be performed in the plasma processing system shown in Fig. 1. In the following, an example will be described in which a control unit 2 controls each part of the plasma processing apparatus 1 to perform this processing method on a substrate W.

[0045] (Step ST1: Providing the substrate) In step ST1, the substrate W is provided in a plasma processing space 10s of the plasma processing apparatus 1. The substrate W is provided on an upper surface of the substrate support 11, and is held on the substrate support 11 by the electrostatic chuck 1111.

[0046] 3 is a diagram showing an example of a cross-sectional structure of a substrate W provided in step ST1. The substrate W has a silicon-containing film SF and a mask MF laminated in this order on an undercoat film UF. The substrate W may be used for manufacturing semiconductor devices including semiconductor memory devices such as DRAMs and 3D-NAND flash memories.

[0047] The undercoat film UF may be, for example, a silicon wafer, an organic film formed on a silicon wafer, a dielectric film, a metal film, a semiconductor film, etc. The undercoat film UF may be configured by laminating a plurality of films.

[0048] The silicon-containing film SF is a film containing silicon. The silicon-containing film SF may be, for example, a silicon oxide film, a silicon nitride film, a silicon oxynitride film (SiON film), a Si-ARC (Silicon-Anti Reflection Carbon) film, or the like. The silicon-containing film SF may be configured by laminating a plurality of films. The silicon-containing film SF may be configured by laminating at least two types of films selected from the group consisting of a silicon oxide film, a silicon nitride film, and a polycrystalline silicon film. For example, the silicon-containing film SF may be configured by alternately laminating a silicon oxide film and a polycrystalline silicon film. Also, for example, the silicon-containing film SF may be configured by alternately laminating a silicon oxide film and a silicon nitride film. Also, for example, the silicon-containing film SF may be configured by alternately laminating a silicon nitride film and a polycrystalline silicon film.

[0049] The mask MF is formed on the upper surface of the silicon-containing film SF. The mask MF has at least one opening OP. The opening OP is a space above the silicon-containing film SF that is surrounded by the side surfaces of the mask MF. That is, in FIG. 3, the upper surface of the silicon-containing film SF has a portion that is covered by the mask MF and a portion that is exposed by the opening OP.

[0050] The opening OP may have any shape in a plan view of the substrate W (when the substrate W is viewed from top to bottom in FIG. 3). The shape may be, for example, a circle, an ellipse, a rectangle, a line, or a combination of one or more of these. The mask MF may have a plurality of openings OP. The plurality of openings OP may each have a hole shape and form an array pattern arranged at regular intervals. Also, the plurality of openings OP may each have a line shape and be arranged at regular intervals to form a line and space pattern.

[0051] The mask MF may be, for example, a carbon-containing film or a metal-containing film. The carbon-containing film may be a spin-on-carbon (SOC) film, an amorphous carbon film, or a photoresist film. The metal-containing film may contain, for example, at least one selected from the group consisting of tungsten, tungsten carbide, titanium nitride, silicon nitride, and polysilicon. The mask MF may be a single-layer mask consisting of one layer, or a multi-layer mask consisting of two or more layers.

[0052] Each of the films constituting the substrate W (the base film UF, the silicon-containing film SF, and the mask MF) may be formed by a CVD (Chemical Vapor Deposition) method, an ALD (Atomic Layer Deposition) method, a spin coating method, or the like. Each of the above films may be a flat film or may have irregularities. The opening OP of the mask MF may be formed by etching the mask MF. The substrate W may further have another film below the base film UF, and the laminated film of the silicon-containing film SF and the base film UF may function as a multilayer mask. In other words, the laminated film of the silicon-containing film SF and the base film UF may be used as a multilayer mask to etch the other film.

[0053] At least a part of the process of forming each film on the substrate W may be performed in the space of the plasma processing chamber 10. In one example, a step of etching the mask MF to form an opening OP may be performed in the plasma processing chamber 10. That is, the opening OP and the etching of the etching film EF described later may be performed consecutively in the same chamber. Also, after all or a part of each film on the substrate W is formed in an apparatus or chamber outside the plasma processing apparatus 1, the substrate W may be carried into the plasma processing space 10s and placed on the upper surface of the substrate support 11 to provide the substrate.

[0054] (Step ST2: Etching the silicon-containing film SF) In step ST2, the silicon-containing film SF is etched. Step ST2 includes step ST21 of supplying a processing gas and step ST22 of generating plasma. In step ST21, a processing gas containing various gases is supplied from the gas supply unit 20 into the plasma processing space 10s. Then, in step ST22, plasma is generated from the processing gas, and the silicon-containing film SF is etched.

[0055] In step ST2, the temperature of the substrate support 11 is set to a target temperature. The target temperature may be, for example, 0° C. or less. The target temperature may be −10° C. or less, −20° C. or less, −30° C. or less, −40° C. or less, −50° C. or less, −60° C. or less, or −70° C. or less.

[0056] Setting the temperature of the substrate support 11 to a target temperature includes, but is not limited to, measuring the temperature of the substrate support 11 and adjusting the temperature of the substrate support 11 by a temperature adjustment module so that the temperature of the substrate support 11 becomes the target temperature. In one example, setting the temperature of the substrate support 11 to a target temperature includes (a) setting the temperature of the substrate W or the temperature of the heat transfer fluid flowing through the flow path 1110a to the target temperature or a temperature different from the target temperature so that the temperature of the substrate support 11 becomes the target temperature, and (b) setting the temperature of the substrate support 11 or the heat transfer fluid flowing through the flow path 1110a to the target temperature or a temperature different from the target temperature so that the temperature of the substrate W becomes the target temperature. Furthermore, "setting" a temperature includes inputting, selecting, or storing the temperature in the control unit 2.

[0057] In this processing method, the temperature of the substrate may be set to the target temperature before step ST1. That is, after the temperature of the substrate support 11 is set to the target temperature, the substrate W may be provided to the substrate support 11.

[0058] In step ST21, a processing gas is supplied into the plasma processing space 10s from the gas supply unit 20. The processing gas is HF gas and PCl a F b (a is an integer of 1 or more, b is an integer of 0 or more, and the sum of a and b is an integer of 5 or less) Gas or PC c H d F e (d and e are each an integer between 1 and 5, and c is an integer between 0 and 9) gas.

[0059] PCl a F b The gas may be, for example, at least one gas selected from the group consisting of PCl3 gas, PClF2 gas, PCl2F gas, and PCl2F3 gas. a F b The gas may be, for example, at least one gas selected from the group consisting of PClF2 gas, PCl2F gas, and PCl2F3 gas.

[0060] PC c H d F e The gas may be, for example, at least one gas selected from the group consisting of PF2CH3 gas, PF(CH3)2 gas, PH2CF3 gas, PH(CF3)2 gas, PCH3(CF3)2 gas, PH2F gas, and PF3(CH3)2 gas.

[0061] The processing gas may include a rare gas such as Ar or He, or an inert gas such as nitrogen gas. The processing gas may not include an inert gas. The flow rate of HF gas may be the largest among the total flow rate of the processing gas excluding the inert gas. The flow rate of HF gas may be 50% by volume or more, 60% by volume or more, 70% by volume or more, or 80% by volume or more of the total flow rate of the processing gas excluding the inert gas.

[0062] PCl a F b Gas or PC c H d F e The flow rate of the gas may be 20% by volume or less, 10% by volume or less, or 5% by volume or less of the total flow rate of the processing gas excluding the inert gas.

[0063] The process gas may further comprise a carbon-containing gas. f F g (f and g are integers of 1 or more) Gas and C h H i F j (wherein h, i, and j are each an integer of 1 or more) may be at least one selected from the group consisting of gases. f F g The gas may be, for example, at least one selected from the group consisting of CF4 gas, C2F6 gas, C2F4 gas, C3F8 gas, and C4F8 gas. h H i F j The gas may be, for example, CH2F2 gas, C3H2F4 gas, C3H2F6 gas, C3H3F5 gas, C4H2F6 gas, C4H5F5 gas, C4H2F8 gas, C5H2F6 gas, C5H2F 10At least one selected from the group consisting of C5H3F7 gas and C5H3F7 gas may be used. The carbon-containing gas may be linear having an unsaturated bond. The linear carbon-containing gas having an unsaturated bond may be, for example, at least one selected from the group consisting of C3F6 (hexafluoropropene) gas, C4F8 (octafluoro-1-butene, octafluoro-2-butene) gas, C3H2F4 (1,3,3,3-tetrafluoropropene) gas, C4H2F6 (trans-1,1,1,4,4,4-hexafluoro-2-butene) gas, C4F8O (pentafluoroethyl trifluorovinyl ether) gas, CF3COF gas (1,2,2,2-tetrafluoroethane-1-one), CHF2COF (difluoroacetic acid fluoride) gas and COF2 (carbonyl fluoride) gas.

[0064] The process gas is a tungsten-containing gas, a boron-containing gas and PCl a F b The gas may further include at least one selected from the group consisting of chlorine-containing gases other than the gas, for example, WF6 gas or BCl3 gas.

[0065] The process gas may contain a gas capable of generating HF species in the plasma processing chamber 10 instead of or together with HF gas. The HF species includes at least one of hydrogen fluoride gas, radicals, and ions. The HF species may be generated from at least one gas selected from the group consisting of HF gas and hydrofluorocarbon gas. The HF species may be generated from a hydrofluorocarbon gas having a carbon number of 2 or more. Examples of gas capable of generating HF species include C h H i F j (h, i, and j are each an integer of 1 or more) Gas, for example, CH2F2 gas, C3H2F4 gas, C3H2F6 gas, C3H3F5 gas, C4H2F6 gas, C4H5F5 gas, C4H2F8 gas, C5H2F6 gas, C5H2F 10At least one gas selected from the group consisting of CH2F2 gas, C3H2F4 gas, C3H2F6 gas, and C4H2F6 gas may be used as the gas capable of generating HF species. In one example, at least one gas selected from the group consisting of CH2F2 gas, C3H2F4 gas, C3H2F6 gas, and C4H2F6 gas is used as the gas capable of generating HF species.

[0066] The process gas is PCl a F b Gas or PC c H d F e Instead of or in addition to gas, PCl v F w C x H y (wherein v, w, x and y are integers of 1 or more) may be used. The processing gas may be PCl a F b Gas or PC c H d F e Instead of or in addition to the gas, a gas containing P (phosphorus), F (fluorine) and a halogen other than F (fluorine) (e.g., Cl, Br or I) in its molecular structure, a gas containing P (phosphorus), F (fluorine), C (carbon) and H (hydrogen) in its molecular structure, or a gas containing P (phosphorus), F (fluorine) and H (hydrogen) in its molecular structure may be used.

[0067] The process gas is PCl a F b Gas or PC c H d F e Instead of or in addition to the gas, a phosphine-based gas may be used. Examples of the phosphine-based gas include phosphine (PH3), a compound in which at least one hydrogen atom of phosphine is substituted with an appropriate substituent, and a phosphinic acid derivative.

[0068] The substituent substituting the hydrogen atom of the phosphine is not particularly limited, and examples thereof include halogen atoms such as a fluorine atom and a chlorine atom; alkyl groups such as a methyl group, an ethyl group, and a propyl group; and hydroxyalkyl groups such as a hydroxymethyl group, a hydroxyethyl group, and a hydroxypropyl group. Examples thereof include a chlorine atom, a methyl group, and a hydroxymethyl group.

[0069] Phosphinic acid derivatives include phosphinic acid (H3O2P), alkylphosphinic acid (PHO(OH)R), and dialkylphosphinic acid (PO(OH)R2).

[0070] As the phosphine-based gas, for example, at least one gas selected from the group consisting of PCH3Cl2 (dichloro(methyl)phosphine) gas, P(CH3)2Cl (chloro(dimethyl)phosphine) gas, P(HOCH2)Cl2 (dichloro(hydroxylmethyl)phosphine) gas, P(HOCH2)2Cl (chloro(dihydroxylmethyl)phosphine) gas, P(HOCH2)(CH3)2 (dimethyl(hydroxylmethyl)phosphine) gas, P(HOCH2)2(CH3) (methyl(dihydroxylmethyl)phosphine) gas, P(HOCH2)3 (tris(hydroxylmethyl)phosphine) gas, H3O2P (phosphinic acid) gas, PHO(OH)(CH3) (methylphosphinic acid) gas, and PO(OH)(CH3)2 (dimethylphosphinic acid) gas may be used.

[0071] 4 is a diagram showing an example of a cross-sectional structure of the substrate W during processing in step ST22. In step ST22, a source RF signal (RF power) is supplied from the first RF generator 31a to the lower electrode and / or the upper electrode, and plasma is generated from the processing gas. In addition, a bias RF signal is supplied from the second RF generator 31b to the lower electrode as a bias signal (power), and a bias potential is generated on the substrate. As a result, active species such as ions and radicals in the generated plasma are attracted to the substrate W, and the silicon-containing film SF is etched through the opening OP of the mask MF.

[0072] As shown in FIG. 4, a recess corresponding to the shape of the opening OP is formed in the silicon-containing film SF. a F b Gas or PC c H d F e The reactive species dissociated from the gas (PCl a Fb seeds, PC c H d F e The silicon-containing film SF is etched by the mask MF and the protective film PF is formed. The protective film PF may be deposited on the top and side surfaces of the mask MF. The protective film PF protects the mask MF during etching of the silicon-containing film SF and may improve the selectivity to the mask MF.

[0073] Considering the function as a protective film, it is preferable that the bonding strength with the elements constituting the mask MF is strong. On the other hand, if the bonding strength is too strong, the protective film PF is excessively deposited on the mask MF, and the opening OP is blocked. a F b Gas or PC c H d F e When gas is used, the bonding strength with the elements (e.g., carbon) contained in the mask MF is stronger than when PF3 gas, BCl3 gas, or BF3 gas is used, but the bonding strength is not as strong as when PCl3 gas is used. a F b Gas or PC c H d F e By including the gas as the processing gas, it is possible to achieve a good balance between protecting the mask MF and preventing the opening OP from being blocked.

[0074] Also, PCl a F b Gas or PC c H d F e A gas is a gas that has multiple functions in one molecule. For example, PCl a F b Gas or PC c H d F e The P (phosphorus) species dissociated from the gas can promote the adsorption of the HF species, which is an etchant, during etching of the silicon-containing film SF. a F b Gas or PC c H d F eThe Cl species dissociated from the gas can contribute to adjusting the shape of the silicon-containing film SF. a F b Gas or PC c H d F e Since this process uses HF gas, the partial pressure of the etchant gas (HF gas) can be made higher than when the same effect is obtained by using two gases, for example, PF3 gas and Cl2 gas, and thus the process can improve the etching rate of the silicon-containing film SF and the selectivity to the mask MF.

[0075] (Appendix 1) 1. A device manufacturing method carried out in a plasma processing apparatus having a chamber, comprising: (a) providing a substrate having a silicon-containing film and a mask on the silicon-containing film in a chamber; (b) In the chamber, HF gas and PCl a F b (a is an integer of 1 or more, b is an integer of 0 or more, and the sum of a and b is an integer of 5 or less) Gas or PC c H d F e (c is an integer of 0 to 5, and d and e are each an integer of 1 to 9) to generate plasma from a process gas containing the gas, and etching the silicon-containing film; A device manufacturing method comprising:

[0076] (Appendix 2) A computer of a plasma processing system including a chamber, a substrate support unit and a plasma generating unit provided in the chamber, (a) providing a substrate having a silicon-containing film and a mask on the silicon-containing film in a chamber; (b) In the chamber, HF gas and PCl a F b (a is an integer of 1 or more, b is an integer of 0 or more, and the sum of a and b is an integer of 5 or less) Gas or PC c H d F e(c is an integer of 0 to 5, and d and e are each an integer of 1 to 9) and a plasma is generated from the processing gas containing the gas, to etch the silicon-containing film. A program that executes control.

[0077] (Appendix 3) A storage medium storing the program described in appendix 2.

[0078] (Appendix 4) HF gas and PCl a F b Gas or PC c H d F e and a gas.

[0079] (Appendix 5) 1. A device manufacturing method carried out in a plasma processing apparatus having a chamber, comprising: (a) providing a substrate having a silicon-containing film and a mask on the silicon-containing film in a chamber; (b) generating plasma from a process gas containing a gas containing H (hydrogen) and F (fluorine) in the chamber and etching the substrate, the phosphorus-containing gas being a gas containing P (phosphorus), F (fluorine) and a halogen other than F (fluorine) in its molecular structure, a gas containing P (phosphorus), F (fluorine), C (carbon) and H (hydrogen) in its molecular structure, or a gas containing P (phosphorus), F (fluorine) and H (hydrogen) in its molecular structure; A device manufacturing method comprising:

[0080] (Appendix 6) A computer of a plasma processing system including a chamber, a substrate support unit and a plasma generating unit provided in the chamber, (a) providing a substrate having a silicon-containing film and a mask on the silicon-containing film in a chamber; (b) generating plasma from a process gas containing a gas containing H (hydrogen) and F (fluorine) in the chamber and etching the substrate, the phosphorus-containing gas being a gas containing P (phosphorus), F (fluorine) and a halogen other than F (fluorine) in its molecular structure, a gas containing P (phosphorus), F (fluorine), C (carbon) and H (hydrogen) in its molecular structure, or a gas containing P (phosphorus), F (fluorine) and H (hydrogen) in its molecular structure; A program that executes control.

[0081] (Appendix 7) A storage medium storing the program described in appendix 6.

[0082] (Appendix 8) An etching gas composition comprising a gas containing H (hydrogen) and F (fluorine), a gas containing P (phosphorus), F (fluorine) and a halogen other than F (fluorine) in its molecular structure, a gas containing P (phosphorus), F (fluorine), C (carbon) and H (hydrogen) in its molecular structure, or a phosphorus-containing gas containing P (phosphorus), F (fluorine) and H (hydrogen) in its molecular structure.

[0083] (Appendix 9) 1. A device manufacturing method carried out in a plasma processing apparatus having a chamber, comprising: (a) providing a substrate having a silicon-containing film and a mask on the silicon-containing film in a chamber; (b) HF species and PCl from the process gas a F b (a is an integer of 1 or more, b is an integer of 0 or more, and the sum of a and b is an integer of 5 or less) c H d F e (c is an integer of 0 to 5, and d and e are each an integer of 1 to 9) to generate plasma containing a species, and etching the silicon-containing film; A device manufacturing method comprising:

[0084] (Appendix 10) A computer of a plasma processing system including a chamber, a substrate support unit and a plasma generating unit provided in the chamber, (a) providing a substrate having a silicon-containing film and a mask on the silicon-containing film in a chamber; (b) HF species and PCl from the process gas a F b (a is an integer of 1 or more, b is an integer of 0 or more, and the sum of a and b is an integer of 5 or less) c H d F e (c is an integer of 0 to 5, and d and e are each an integer of 1 to 9) to generate plasma containing a species, and etching the silicon-containing film. A program that executes control.

[0085] (Appendix 11) A storage medium storing the program according to claim 10.

[0086] Various modifications may be made to the embodiments of the present disclosure without departing from the scope and spirit of the present disclosure. For example, the present processing method may be performed using a plasma processing apparatus using any plasma source such as microwave plasma, other than the capacitively coupled plasma processing apparatus 1. [Explanation of symbols]

[0087] 1: Plasma processing apparatus, 2: Control unit, 10: Plasma processing chamber, 10s: Plasma processing space, 11: Substrate support unit, 20: Gas supply unit, PF: Protective film, MF: Mask, SF: Silicon-containing film, UF: Base film, W: Substrate

Claims

1. 1. An etching method performed in a plasma processing apparatus having a chamber, comprising: (a) providing a substrate having a silicon-containing film and a mask on the silicon-containing film in a chamber; (b) mixing HF gas and PCl ａ F ｂ (a is an integer of 1 or more, b is an integer of 1 or more, and the sum of a and b is an integer of 5 or less) Gas or PC ｃ H ｄ F ｅ (c is an integer of 1 to 5, and d and e are each an integer of 1 to 9) to generate plasma from a process gas containing a gas, and etching the silicon-containing film; An etching method comprising:

2. The process gas is ａ F ｂ The etching method of claim 1 comprising a gas.

3. The PCl ａ F ｂ The gas is PClF ２ Gas, PCl ２ F gas and PCl ２ F ３ 3. The etching method according to claim 1, wherein the gas is at least one selected from the group consisting of gases.

4. The PC ｃ H ｄ F ｅ The gas is PF ２ CH ３ Gas, PF(CH ３ ) ２ Gas, pH ２ CF ３ Gas, pH (CF ３ ) ２ Gas, PCH ３ (CF ３ ) ２ Gas and PF ３ (CH ３ ) ２ 4. The etching method according to claim 1, wherein the gas is at least one kind of gas selected from the group consisting of gases.

5. 5. The etching method according to claim 1, wherein, in the step (b), the process gas supplied into the chamber has a largest flow rate of HF gas, excluding an inert gas.

6. 6. The etching method according to claim 5, wherein the flow rate of the HF gas is 50% by volume or more of the total flow rate of the process gas excluding the inert gas.

7. The PCl ａ F ｂ Gas or PC ｃ H ｄ F ｅ 7. The etching method according to claim 1, wherein a flow rate of the gas is 20% by volume or less of a total flow rate of the process gas excluding the inert gas.

8. The process gas is ｆ F ｇ The etching method according to claim 1 or 7, further comprising a gas (wherein f and g are each an integer of 1 or more).

9. The process gas is ｈ H ｉ F ｊ The etching method according to claim 1 , further comprising a gas (wherein h, i, and j are each an integer of 1 or more).

10. The process gas is WF ６ Gas and / or BCl ３ The etching method of claim 1 , further comprising a gas.

11. 11. The etching method according to claim 1, wherein in (b), a temperature of a substrate support part that supports the substrate is set to 0[deg.] C. or lower.

12. The etching method according to claim 1 , wherein the mask is a carbon-containing film or a metal-containing film.

13. 1. An etching method performed in a plasma processing apparatus having a chamber, comprising: (a) providing a substrate having a silicon-containing film and a mask on the silicon-containing film in a chamber; (b) generating plasma from a process gas containing a gas containing H (hydrogen) and F (fluorine) in the chamber and etching the substrate, the phosphorus-containing gas being a gas containing P (phosphorus), F (fluorine) and a halogen other than F (fluorine) in its molecular structure, or a gas containing P (phosphorus), F (fluorine), C (carbon) and H (hydrogen) in its molecular structure; An etching method comprising:

14. The gas containing H and F is HF gas or C ｈ H ｉ F ｊ The etching method according to claim 13 , further comprising at least one of the following gases: (h, i, and j each being an integer of 1 or more).

15. 15. The etching method of claim 13, wherein the process gas further comprises a carbon-containing gas.

16. 1. An etching method performed in a plasma processing apparatus having a chamber, comprising: (a) providing a substrate having a silicon-containing film and a mask on the silicon-containing film in a chamber; (b) HF species and PCl from the process gas. ａ F ｂ (a is an integer of 1 or more, b is an integer of 1 or more, and the sum of a and b is an integer of 5 or less) species or PC ｃ H ｄ F ｅ (c is an integer of 1 to 5, and d and e are each an integer of 1 to 9) to etch the silicon-containing film; An etching method comprising:

17. 17. The etching method of claim 16, wherein the HF species is generated from at least one gas selected from the group consisting of HF gas and hydrofluorocarbon gas.

18. 17. The etching method of claim 16, wherein the HF species is generated from a hydrofluorocarbon gas having two or more carbon atoms.

19. The HF species include HF gas, CH ２ F ２ Gas, C. ３ H ２ F ４ Gas, C. ３ H ２ F ６ Gas and C ４ H ２ F ６ 20. The method of claim 16, wherein the at least one gas selected from the group consisting of gases.

20. 1. A plasma processing system comprising a chamber, a process gas supply and a controller, The control unit is (a) providing a substrate having a silicon-containing film and a mask on the silicon-containing film in the chamber; (b) The process gas supply unit supplies HF gas and PCl ａ F ｂ (a is an integer of 1 or more, b is an integer of 1 or more, and the sum of a and b is an integer of 5 or less) Gas or PC ｃ H ｄ F ｅ (c is an integer of 1 to 5, and d and e are each an integer of 1 to 9) into the chamber to generate plasma and etch the silicon-containing film; Plasma processing systems.

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