Substrate processing method and substrate processing system

Abstract

To provide a technology for improving an etching shape of an etching target film.SOLUTION: A substrate processing method includes the steps of: (a) providing a substrate including an etching target film and a mask on the etching target film, in which a mask includes a side wall regulating at least one opening; (b) selectively forming an additional mask containing carbon by using a plasma generated from a processing gas containing carbon and hydrogen; and (c) etching the etching target film by using the plasma generated from an etching gas.SELECTED DRAWING: Figure 4

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a technique for etching a laminated film of a silicon-containing film.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a technique for improving the etching shape of a film to be etched.

Means for Solving the Problems

[0005] A substrate processing method according to an exemplary embodiment of the present disclosure includes: (a) providing a substrate including a film to be etched and a mask on the film to be etched, the mask including sidewalls defining at least one opening; (b) selectively forming an additional mask containing carbon on the mask using plasma generated from a processing gas containing carbon and hydrogen; and (c) etching the film to be etched using plasma generated from an etching gas.

Effects of the Invention

[0006] According to an exemplary embodiment of the present disclosure, a technique for improving the etching shape of a film to be etched can be provided.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Embodiments for Carrying Out the Invention

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

[0009] In one exemplary embodiment, there is provided a substrate processing method including: (a) a step of providing a substrate including a film to be etched and a mask on the film to be etched, the mask including sidewalls defining at least one opening; (b) a step of selectively forming an additional mask containing carbon on the mask using plasma generated from a processing gas containing carbon and hydrogen; and (c) a step of etching the film to be etched using plasma generated from an etching gas.

[0010] In one exemplary embodiment, step (b) is performed after step (a).

[0011] In one exemplary embodiment, the substrate in step (a) includes a first film on the mask, and the substrate processing method further includes (d) a step of removing the first film between step (a) and step (b).

[0012] In one exemplary embodiment, a cycle including steps (b) and (c) in this order is performed multiple times.

[0013] In one exemplary embodiment, step (c) is performed after step (a), and then a cycle including steps (b) and (c) in this order is performed one or more times.

[0014] In one exemplary embodiment, the mask has a thickness of 10 μm or less.

[0015] In one exemplary embodiment, the mask includes at least one selected from the group consisting of a carbon-containing film, a silicon-containing film, and a metal-containing film.

[0016] In one exemplary embodiment, the additional mask has a thickness of 0.2 μm or more.

[0017] In one exemplary embodiment, the additional mask has a thickness of 2 μm or less.

[0018] In one exemplary embodiment, the additional mask includes an amorphous carbon film.

[0019] In one exemplary embodiment, the film to be etched includes a laminated film containing two or more different silicon-containing films.

[0020] In one exemplary embodiment, the film to be etched includes a laminated film in which a silicon oxide film and a silicon nitride film are alternately laminated.

[0021] In one exemplary embodiment, the opening of the mask is formed by plasma etching.

[0022] There is provided a substrate processing system including a substrate support portion disposed in a chamber, a plasma generation portion, and a control portion, wherein the control portion executes: (a) control to provide a substrate including a film to be etched and a mask on the film to be etched to the substrate support portion, the mask including sidewalls defining at least one opening; (b) control to generate a plasma from a processing gas containing carbon and hydrogen by the plasma generation portion and selectively form an additional mask containing carbon on the mask; and (c) control to generate a plasma from an etching gas by the plasma generation portion and etch the film to be etched.

[0023] In one exemplary embodiment, a substrate processing system includes a plurality of chambers and a transfer module capable of transferring a substrate within a vacuum atmosphere for the plurality of chambers, and a control unit executes the controls of (a), (b), and (c) while maintaining the vacuum atmosphere using any one of the plurality of chambers.

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

[0025] <An example of a plasma processing system> FIG. 1 is a diagram for explaining a configuration example of a plasma processing system. In one embodiment, the plasma processing system includes a plasma processing apparatus 1 and a control unit 2. The plasma processing system is an example of a substrate processing system, and the plasma processing apparatus 1 is an example of a substrate processing apparatus. The plasma processing apparatus 1 includes a plasma processing chamber 10, a substrate support portion 11, and a plasma generation portion 12. The plasma processing chamber 10 has a plasma processing space. The plasma processing chamber 10 also has at least one gas supply port for supplying at least one processing gas to the plasma processing space and at least one gas discharge port for discharging gas from the plasma processing space. The gas supply port is connected to a gas supply unit 20 described later, and the gas discharge port is connected to an exhaust system 40 described later. The substrate support portion 11 is disposed within the plasma processing space and has a substrate support surface for supporting a substrate.

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

[0027] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to execute various processes described in the present disclosure. The control unit 2 may be configured to control each element of the plasma processing apparatus 1 to execute the various processes described herein. In one embodiment, part or all of the control unit 2 may be included in the plasma processing 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 by, for example, 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 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 RAM (Random Access Memory), a ROM (Read Only Memory), an HDD (Hard Disk Drive), an SSD (Solid State Drive), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing apparatus 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. FIG. 2 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 (also simply referred to as the "chamber"), a gas supply unit 20, a power supply 30, and an exhaust system 40. Further, 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 within 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 part 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 housing of the plasma processing chamber 10.

[0030] The substrate support unit 11 includes a main body portion 111 and a ring assembly 112. The main body portion 111 has a central region 111a for supporting the substrate W and an annular region 111b for supporting the ring assembly 112. A wafer is an example of the substrate W. The annular region 111b of the main body portion 111 surrounds the central region 111a of the main body portion 111 in a plan view. The substrate W is disposed on the central region 111a of the main body portion 111, and the ring assembly 112 is disposed on the annular region 111b of the main body portion 111 so as to surround the substrate W on the central region 111a of the main body portion 111. Accordingly, the central region 111a is also referred to as a substrate support surface for supporting the substrate W, and the annular region 111b is also referred to as a ring support 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 member. The conductive member of the base 1110 can function as a lower electrode. The electrostatic chuck 1111 is disposed on the base 1110. The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic electrode 1111b disposed within the ceramic member 1111a. The ceramic member 1111a has a central region 111a. In one embodiment, the ceramic member 1111a also has an annular region 111b. 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 an RF power supply 31 and / or a DC power supply 32 described later may be disposed within the ceramic member 1111a. In this case, at least one RF / DC electrode functions as a lower electrode. When a bias RF signal and / or a 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. Note that the conductive member of the base 1110 and 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. Accordingly, the substrate support portion 11 includes at least one lower electrode.

[0032] 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 ring is formed of a conductive material or an insulating material, and the cover ring is formed of an insulating material.

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

[0034] The shower head 13 is configured to introduce at least one process gas from the gas supply unit 20 into the plasma processing space 10s. The shower head 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and a plurality of gas introduction ports 13c. The process 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 plurality of gas introduction ports 13c. Further, the shower head 13 includes at least one upper electrode. The gas introduction portion may include, in addition to the shower head 13, one or more side gas injection portions (SGI) attached to one or more openings formed in 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 the corresponding gas source 21 to the shower head 13 via the corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Further, the gas supply unit 20 may include at least one flow modulation device for modulating or pulsing the flow rate 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. Thereby, plasma is formed from at least one processing gas supplied to the plasma processing space 10s. Accordingly, the RF power supply 31 can function as at least a part of the plasma generation unit 12. Also, by supplying a bias RF signal to at least one lower electrode, a bias potential is generated on the substrate W, and the ion component in the formed plasma can be drawn into the substrate W.

[0037] In one embodiment, the RF power supply 31 includes a first RF generation unit 31a and a second RF generation unit 31b. The first RF generation 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 within the range of 10 MHz to 150 MHz. In one embodiment, the first RF generation unit 31a may be configured to generate a plurality of source RF signals having different frequencies. 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 generation unit 31b is coupled to at least one lower electrode via at least one impedance matching circuit and is configured to generate a bias RF signal (bias RF power). The frequency of the bias RF signal may be the same as or different from the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency lower than the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 100 kHz to 100 MHz. In one embodiment, the second RF generation unit 31b may be configured to generate a plurality of bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to at least one lower electrode. Also, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0039] Also, 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 generation unit 32a and a second DC generation unit 32b. In one embodiment, the first DC generation unit 32a is connected to at least one lower electrode and is configured 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 generation unit 32b is connected to at least one upper electrode and is configured 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 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 pulse waveform that is rectangular, trapezoidal, triangular, or a combination thereof. In one embodiment, a waveform generation unit for generating a sequence of voltage pulses from a DC signal is connected between the first DC generation unit 32a and at least one lower electrode. Accordingly, the first DC generation unit 32a and the waveform generation unit constitute a voltage pulse generation unit. When the second DC generation unit 32b and the waveform generation unit constitute a voltage pulse generation unit, the voltage pulse generation unit 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 within one period. Note that the first and second DC generation units 32a, 32b may be provided in addition to the RF power supply 31, or the first DC generation unit 32a may be provided in place of the second RF generation unit 31b.

[0041] The exhaust system 40 can be connected to, for example, a gas outlet 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 turbo molecular pump, a dry pump, or a combination thereof.

[0042] FIG. 3 is a diagram for explaining an example of the configuration of a substrate processing system. The substrate processing system PS includes substrate processing chambers (chambers) PM1 to PM6 (hereinafter also collectively referred to as "substrate processing modules PM"), a transfer module TM, load lock modules LLM1 and LLM2 (hereinafter also collectively referred to as "load lock modules LLM"), a loader module LM, and load ports LP1 to LP3 (hereinafter also collectively referred to as "load ports LP"). The control unit CT controls each component of the substrate processing system PS to execute a given process on the substrate W.

[0043] The substrate processing module PM performs processes such as etching, trimming, film formation, annealing, doping, lithography, cleaning, ashing, etc. on the substrate W inside it. A part of the substrate processing module PM may be a capacitively coupled plasma processing apparatus as shown in FIG. 2. That is, at least one of the substrate processing chambers PM1 to PM6 may be coupled to a capacitively coupled plasma generation unit. A part of the substrate processing module PM may be an inductively coupled plasma processing apparatus. That is, at least one of the substrate processing chambers PM1 to PM6 may be coupled to an inductively coupled plasma generation unit. A part of the substrate processing module PM may be a measurement module, and may measure, for example, using an optical method, the film thickness of the film formed on the substrate W, the dimensions of the pattern formed on the substrate W, etc.

[0044] The transfer module TM has a transfer device for transferring the substrate W, and transfers the substrate W between the substrate processing modules PM or between the substrate processing module PM and the load lock module LLM. The substrate processing module PM and the load lock module LLM are arranged adjacent to the transfer module TM. The transfer module TM, the substrate processing module PM, and the load lock module LLM are spatially isolated or connected by an openable and closable gate valve.

[0045] The load lock modules LLM1 and LLM2 are provided between the transfer module TM and the loader module LM. The load lock module LLM can switch the pressure inside it between atmospheric pressure and vacuum. "Atmospheric pressure" can be the pressure outside each module included in the substrate processing system PS. Also, "vacuum" is a pressure lower than atmospheric pressure, and can be, for example, a medium vacuum of 0.1 Pa to 100 Pa. The load lock module LLM transfers the substrate W from the loader module LM at atmospheric pressure to the transfer module TM at vacuum, and also transfers it from the transfer module TM at vacuum to the loader module LM at atmospheric pressure.

[0046] The loader module LM has a transport device for transporting the substrate W, and transports the substrate W between the load lock module LLM and the load port LP. Inside the load port LP, for example, a FOUP (Front Opening Unified Pod) capable of storing 25 substrates W or an empty FOUP can be placed. The loader module LM removes the substrate W from the FOUP in the load port LP and transports it to the load lock module LLM. The loader module LM also removes the substrate W from the load lock module LLM and transports it to the FOUP in the load port LP.

[0047] The controller CT controls each component of the substrate processing system PS to perform a given process on the substrate W. The controller CT stores a recipe in which a process procedure, process conditions, transport conditions, etc. are set, and controls each component of the substrate processing system PS to perform a given process on the substrate W in accordance with the recipe. The controller CT may have some or all of the functions of the controller 2 shown in FIG.

[0048] <An example of a substrate processing method> (First embodiment) FIG. 4 is a flowchart showing an example of a substrate processing method according to the first embodiment (hereinafter also referred to as "this processing method"). As shown in FIG. 4, in one embodiment, this processing method includes a step ST1 of providing a substrate, a step ST2 of selectively forming an additional mask on a mask of the substrate, and a step ST3 of etching an etching target film. In one embodiment, the steps ST1, ST2, and ST3 are performed in this order. In one embodiment, the processing in each step may be performed in a substrate processing system (see FIG. 3). In the following example, a control unit CT controls each part of the substrate processing system to perform this processing method.

[0049] (Step ST1: Providing the substrate) In one embodiment, in step ST1, as shown in FIG. 2, the substrate W is provided in the chamber 10 of the plasma processing apparatus 1. The substrate W is provided in the central region 111a of the substrate support portion 11 and is held by the electrostatic chuck 1111 on the substrate support portion 11.

[0050] FIG. 5 is a diagram for explaining a configuration example of the substrate W provided in step ST1. The substrate W includes a base film UF, a stacked film SF on the base film UF, and a mask MK on the stacked film SF. The substrate W may be used for manufacturing semiconductor devices. The semiconductor devices include, for example, memory devices such as DRAM and 3D-NAND flash memory, and logic devices.

[0051] In one embodiment, the base film UF is a silicon wafer, an organic film, a dielectric film, a metal film, a semiconductor film, etc. formed on a silicon wafer. The base film UF may be composed of a plurality of films stacked.

[0052] In one embodiment, the stacked film SF is a film to be etched in this processing method. In one embodiment, the stacked film SF includes two or more different silicon-containing films. In one embodiment, the stacked film SF includes a stacked structure in which a silicon oxide film SF1 and a silicon nitride film SF2 are alternately stacked. The stacked film SF may have a thickness of 5 μm or more, or 10 μm or more. The stacked film SF may have 20 layers or more, 50 layers or more, or 100 layers or more. The stacked film SF may include two or more films selected from the group consisting of a single crystal silicon film, a polycrystalline silicon film, a silicon oxide film, and a silicon nitride film.

[0053] In one embodiment, the mask MK is a film that functions as a mask in the etching of the stacked film SF. The mask MK may be a hard mask. The mask MK includes at least one selected from the group consisting of a carbon-containing film, a silicon-containing film, and a metal-containing film. The mask MK may be an amorphous carbon film. The mask MK may be doped with an element such as phosphorus, boron, or nitrogen. The mask MK may be a film including at least one selected from the group consisting of WC (tungsten carbide), WSi (tungsten silicide), WSiN, and WSiC. The mask MK may be a single-layer mask composed of one film, or may be a multi-layer mask composed of two or more films. The mask MK may have a thickness of 10 μm or less, or 5 μm or less.

[0054] The mask MK has an upper surface U1 and side walls S1 that define at least one opening OP1 on the stacked film SF. The opening OP1 is a space on the stacked film SF and is surrounded by the side walls S1 of the mask MK. That is, the upper surface of the stacked film SF has a region covered by the mask MK and a region exposed at the bottom of the opening OP1.

[0055] The opening OP1 may have an arbitrary shape in a plan view of the substrate W, that is, when the substrate W is viewed in the direction from top to bottom in FIG. 5. The shape may be, for example, a circle, an ellipse, a rectangle, a line, or a combination of one or more of these. The mask MK may have a plurality of side walls S1, and the plurality of side walls may define a plurality of openings OP1. The plurality of openings OP1 may each have a linear shape and may be arranged at regular intervals to form a line-and-space pattern. Also, the plurality of openings OP1 may each have a hole shape and may form an array pattern. The width of the opening OP1 may be 120 nm or less, 100 nm or less, 80 nm or less, or 50 nm or less.

[0056] Each film (underlying film UF, stacked film SF, mask MK) constituting the substrate W may be formed by, for example, chemical vapor deposition (CVD), atomic layer deposition (ALD), molecular layer deposition (MLD), spin coating method, etc. In one embodiment, at least a part of the process of forming each film of the substrate W may be performed as a part of process ST1. In one embodiment, all or part of each film of the substrate W may be performed in the same substrate processing system PS or plasma processing apparatus 1 (chamber 10) as in process ST1. Further, after all or part of each film of the substrate W is formed in an external apparatus or chamber, the substrate W may be provided in the chamber of the plasma processing apparatus 1 that performs process ST1.

[0057] (Process ST2: Formation of additional mask) FIG. 6 is a diagram for explaining a configuration example of the substrate W on which the additional mask MK1 is formed in process ST2. In one embodiment, in process ST2, the additional mask MK1 is selectively formed on the mask MK of the substrate W. The additional mask MK1 is formed using the plasma CVD method. Note that "on the mask MK" includes not only the upper surface of the mask MK but also the upper surface of the film on the upper surface of the mask MK. Also, "selectively" includes selecting the exposed portion facing upward on the mask MK from among the entire exposed portion of the mask MK.

[0058] In one embodiment, in process ST2, a first processing gas is supplied into the chamber 10 from the shower head 13 of the plasma processing apparatus 1 shown in FIG. 2. The temperature of the substrate support portion 11 or the substrate W may be controlled to a first temperature. The first temperature may be 200°C or higher.

[0059] The first processing gas is a gas containing carbon and hydrogen. The first processing gas may contain a hydrocarbon gas (CxHy) (x and y are integers of 1 or more). The hydrocarbon gas is C 2 H 2 gas, C 3 H 6It may be a gas. The first processing gas may further contain an inert gas. The inert gas may be a noble gas such as Ar gas, He gas, and Kr gas, or N 2 It may be a gas.

[0060] In one embodiment, plasma is generated from the first processing gas supplied into the chamber 10. In this case, a source RF signal is supplied from the power supply 30 to the upper electrode and / or the lower electrode, whereby a high-frequency electric field is generated on the substrate support 11, and plasma is generated from the first processing gas in the plasma processing space 10s. The source RF signal has a frequency of 40 MHz or higher. The source RF signal has a first power. The first power may be in the range of 100 W to 500 W.

[0061] When plasma is generated, a bias signal is supplied to the substrate support 11. The bias signal may be a bias RF signal supplied from the RF power supply 31 or a bias DC signal supplied from the DC power supply 32. The bias DC signal may be a DC pulse voltage. The DC pulse voltage may be 200 V or less in absolute value. The duty ratio of the DC pulse voltage may be 20% or less, and may be in the range of 5% to 20%, for example, about 10%. Also, the frequency of the DC pulse voltage may be in the range of 100 kHz to 1000 kHz. A bias potential is generated between the plasma and the substrate W, and ions and radicals in the plasma are attracted to the substrate W.

[0062] As shown in FIG. 6, in one embodiment, carbon ions in the plasma are selectively deposited on the upper surface U1 of the mask MK, and an additional mask MK1 is formed. Deposition on the side wall S1 of the mask MK is blocked by hydrogen radicals in the plasma. The additional mask MK1 is formed substantially only on the upper surface U1 of the mask MK. The additional mask MK1 has a thickness of 0.2 μm or more. The additional mask MK1 has a thickness of 2 μm or less. The combined thickness of the mask MK and the additional mask MK1 may be 6 μm or more or 10 μm or more.

[0063] (Step ST3: Etching of the laminated film SF) FIG. 7 is a diagram for explaining a configuration example of a substrate W on which a stacked film SF is etched in step ST3. In step ST3, the stacked film SF is etched using plasma generated from an etching gas. Step ST3 may be performed in the chamber of the same plasma processing apparatus 1 as in step ST2, or may be performed in the chamber of another plasma processing apparatus 1. When performed in another plasma processing apparatus 1, in the substrate processing system PS, the substrate W may be transported from the plasma processing apparatus 1 in which step ST2 is performed to another plasma processing apparatus 1.

[0064] In one embodiment, in step ST3, an etching gas is supplied from the shower head 13 shown in FIG. 2 into the plasma processing space 10s. The etching gas may include hydrogen fluoride gas and at least one carbon-containing gas selected from the group consisting of CF gas (fluorocarbon gas) and CHF gas (hydrofluorocarbon gas). In one embodiment, the etching gas may include hydrogen fluoride gas, CF gas, CHF gas, an oxygen-containing gas, and a fluorine-containing gas containing no carbon.

[0065] In one embodiment, plasma is generated from the etching gas supplied into the chamber 10. In this case, a source RF signal is supplied from the power supply 30 to the upper electrode and / or the lower electrode, whereby a high-frequency electric field is generated on the substrate support 11, and plasma is generated from the etching gas in the plasma processing space 10s. The source RF signal may have a frequency of 13 MHz or higher. The source RF signal may have a first power. The first power may be 1 kW or higher.

[0066] When plasma is generated, a bias signal is supplied to the substrate support portion 11. The bias signal may be a bias RF signal supplied from the RF power supply 31 or a bias DC signal supplied from the DC power supply 32. A bias potential is generated between the plasma and the substrate W. Active species such as ions and radicals in the plasma are attracted to the substrate W, and the laminated film SF is etched by the active species. The etching may be anisotropic etching using plasma of a fluorocarbon-based gas or plasma of a hydrofluorocarbon-based gas.

[0067] As shown in FIG. 7, in one embodiment, a portion of the laminated film SF that is not covered by the mask MK and the additional mask MK1 (the portion exposed at the opening OP1) is etched, and an opening OP2 is formed in the laminated film SF. An opening OP2 having an aspect ratio (A / R) of 100 or more may be formed in the laminated film SF. The opening OP2 may have, for example, a critical dimension (CD) of 80 nm or less and a depth of 10 μm or more.

[0068] Thereafter, the mask MK on the substrate W is removed by ashing. The ashing of the mask MK may be performed using, for example, plasma of an oxygen-based gas.

[0069] According to this exemplary embodiment, the substrate processing method includes a step ST1 of providing a substrate, a step ST2 of selectively forming an additional mask MK1 containing carbon on the mask MK using plasma generated from a processing gas containing carbon and hydrogen, and a step ST3 of etching a film to be etched using plasma generated from an etching gas. Generally, as the mask becomes thicker (the opening becomes deeper), the dimensional accuracy of the opening formed in the mask decreases. According to this exemplary embodiment, since the additional mask MK1 is added later on the mask MK, the thickness of the mask MK at the time of initial formation can be suppressed, and thereby the dimensional accuracy of the opening of the mask MK can be improved. As a result, the etching shape when etching the film to be etched using the mask can be improved.

[0070] In the illustrated embodiment, the opening OP1 of the mask MK is formed by plasma etching. In this case, as shown in FIG. 8, this processing method may include a step ST0-1 of forming the mask MK on the stacked film SF, and a step ST0-2 of patterning the mask MK to form the opening OP1.

[0071] In one embodiment, in step ST0-1, as shown in FIG. 9, the mask MK is formed on the stacked film SF. The mask MK may be formed using various methods such as CVD method, ALD method, MLD method, spin coating method, etc.

[0072] In step ST0-2, as shown in FIG. 10, a first film F1 having an opening OP3 is formed on the mask MK. The first film F1 may be a silicon-containing film. The opening OP3 of the first film F1 is formed by a lithography process. In this case, first, a flat first film F1 is formed on the mask MK, and an antireflection film F2 and a resist film F3 are formed on the first film F1. Next, a resist pattern having an opening pattern is formed by exposure processing and development processing, and then the first film F1 is etched using the resist pattern. Thereby, the opening OP3 is formed in the first film F1.

[0073] Thereafter, as shown in FIG. 11, the first film F1 including the opening OP3 is made to function as a mask, the mask MK is etched, and the opening OP1 is formed. Note that step ST0-1 and / or step ST0-2 may be performed in the same substrate processing system PS as step ST2 or step ST3.

[0074] When forming the opening OP1 of the mask MK by plasma etching, if the mask MK is thick, the vertical component of ions in the plasma can be lost during plasma etching. In this case, the lower part of the opening of the mask MK may become narrow, the side wall of the opening of the mask MK may be etched laterally, and the shape of the opening of the mask MK may be defective. According to this exemplary embodiment, in step ST2, an additional mask MK1 is formed, so that when forming the opening OP1 of the mask MK, the thickness of the mask MK can be suppressed. As a result, defective shapes of the opening of the mask MK can be avoided, and as a result, the etching shape of the film to be etched can be improved.

[0075] In this exemplary embodiment, the substrate W provided in step ST1 may have a first film F1 on the mask MK. The first film F1 may be what remains after etching for forming the opening OP1 of the mask MK. In this case, as shown in FIG. 12, this processing method may include a step ST4 of removing the first film F1 between step ST1 and step ST2.

[0076] In step ST4, the first film F1 is removed by a processing gas or a processing liquid. The first film F1 may be removed, for example, using a chemical solution in which HF and water are mixed. Thereby, the upper surface U1 of the mask MK is planarized. In the next step ST2, an additional mask MK1 is formed on the planarized mask MK.

[0077] In the present exemplary embodiment, a cycle including steps ST2 and ST3 in this order may be performed a plurality of times. FIG. 13 is a flowchart showing an example of this processing method. As shown in FIG. 14, in step ST3, a portion of the laminated film SF that is not covered by the mask MK and the additional mask MK1 (the portion exposed in the opening OP1) is etched, and a recess R1 is formed in a part of the film of the laminated film SF. Then, when the cycle including steps ST2 and ST3 has not been performed a predetermined number of times set in advance, steps ST2 and ST3 are performed again. As shown in FIG. 15, an additional mask MK1 is formed on the mask MK, and then the laminated film SF is etched so that the bottom of the recess R1 becomes deeper. Then, when the cycle including steps ST2 and ST3 has been performed the predetermined number of times, this processing method ends. At this time, an opening OP2 as shown in FIG. 7 may be formed in the laminated film SF. The predetermined number of cycles may be 2 or more, 5 or more, 10 or more. Note that when the mask MK becomes smaller than a predetermined thickness in step ST3, the cycle of steps ST2 and ST3 may be performed again.

[0078] When plasma etching an etching target film using a mask, as the mask is gradually eroded and the remaining film thickness of the mask becomes smaller, the side walls are etched laterally at the opening of the etching target film, and so-called bowing may occur. According to the present exemplary embodiment, since a cycle including steps ST2 and ST3 in this order is performed a plurality of times, an additional mask MK1 can be added during etching, and the film thickness of the entire mask can be maintained. As a result, bowing is suppressed, and the etching shape of the etching target film can be improved.

[0079] (Second Embodiment) In the present processing method in the present exemplary embodiment, step ST3 is performed after step ST1, and then a cycle including steps S2 and ST3 in this order is performed one or more times. FIG. 16 is a flowchart showing an example of this processing method.

[0080] In one embodiment, in step ST1, as shown in FIG. 5, a substrate W including a base film UF, a stacked film SF on the base film UF, and a mask MK on the stacked film SF is provided. The substrate W is provided in a chamber 10 of a plasma processing apparatus 1 where step ST3 is performed.

[0081] Next, step ST3 is performed, and the stacked film SF is etched using plasma generated from an etching gas. As shown in FIG. 17, in one embodiment, a portion of the stacked film SF that is not covered by the mask MK (the portion exposed in the opening OP1) is etched, and a recess R1 is formed in the stacked film SF.

[0082] Next, step ST2 is performed, and as shown in FIG. 18, an additional mask MK1 is selectively formed on the mask MK of the substrate W.

[0083] Next, step ST3 is performed, and as shown in FIG. 19, the stacked film SF is etched using plasma generated from an etching gas. A portion of the stacked film SF that is not covered by the mask MK and the additional mask MK1 (the portion exposed in the opening OP1) is etched, and a deeper recess R2 is formed in the stacked film SF.

[0084] And if a cycle including step ST2 and step ST3 has not been performed a preset number of times, steps ST2 and ST3 are performed again. When a cycle including steps ST2 and ST3 has been performed the preset number of times, this processing method ends. At this time, an opening OP2 as shown in FIG. 7 may be formed in the stacked film SF. The cycle including steps ST2 and ST3 may be performed two or more times. Note that the conditions of each step in this embodiment may be the same as those in the first embodiment above.

[0085] According to the illustrated embodiment, after steps ST1 and ST3, since a cycle including steps ST2 and ST3 in this order is performed one or more times, an additional mask MK1 can be added during etching, and the film thickness of the entire mask can be maintained. As a result, the etching shape of the film to be etched can be improved.

[0086] In the above first and second embodiments, when steps ST2 and ST3, and their repetitions are performed, in the substrate processing system PS, the substrate may be continuously processed while maintaining a vacuum atmosphere using the transfer module TM and any one of the chambers of the substrate processing chambers PM1 to PM6.

[0087] The film to be etched in the above first and second embodiments is not limited to the stacked film SF. The film to be etched may be at least one single-layer film or a multilayer film selected from the group consisting of a single-crystalline silicon film, a polycrystalline silicon film, a silicon oxide film, and a silicon nitride film.

[0088] In the above first and second embodiments, the present processing method is not limited to an inductively coupled plasma processing apparatus, and may be performed using other types of plasma processing apparatuses, for example, a plasma processing apparatus that generates capacitively coupled plasma, a plasma processing apparatus that generates ECR plasma, a plasma processing apparatus that generates helicon wave-excited plasma, or a plasma processing apparatus that generates surface wave plasma.

[0089] The present disclosure may include, for example, the following configurations.

[0090] (Appendix 1) (a) A step of providing a substrate including a film to be etched and a mask on the film to be etched, the mask including sidewalls defining at least one opening, and the step, (b) A step of selectively forming an additional mask containing carbon on the mask using plasma generated from a processing gas containing carbon and hydrogen, (c) Etching the film to be etched using plasma generated from the etching gas, and a substrate processing method including the same.

[0091] (Appendix 2) The substrate processing method according to Appendix 1, wherein the step (b) is performed after the step (a).

[0092] (Appendix 3) The substrate in the step (a) includes a first film on the mask. (d) The substrate processing method according to Appendix 2, further including a step of removing the first film between the step (a) and the step (b).

[0093] (Appendix 4) The substrate processing method according to Appendix 2 or 3, wherein a cycle including the step (b) and the step (c) in this order is performed multiple times.

[0094] (Appendix 5) The substrate processing method according to Appendix 1, wherein the step (c) is performed after the step (a), and then a cycle including the step (b) and the step (c) in this order is performed one or more times.

[0095] (Appendix 6) The substrate processing method according to any one of Appendices 1 to 5, wherein the mask has a thickness of 10 μm or less.

[0096] (Appendix 7) The substrate processing method according to any one of Appendices 1 to 6, wherein the mask includes at least one selected from the group consisting of a carbon-containing film, a silicon-containing film, and a metal-containing film.

[0097] (Appendix 8) The substrate processing method according to any one of Appendices 1 to 7, wherein the additional mask has a thickness of 0.2 μm or more.

[0098] (Appendix 9) The substrate processing method according to any one of Appendices 1 to 8, wherein the additional mask has a thickness of 2 μm or less.

[0099] (Supplementary Note 10) The additional mask is the substrate processing method according to any one of Supplementary Notes 1 to 9, including an amorphous carbon film.

[0100] (Supplementary Note 11) The film to be etched is the substrate processing method according to any one of Supplementary Notes 1 to 10, including a laminated film containing two or more different silicon-containing films.

[0101] (Supplementary Note 12) The film to be etched is the substrate processing method according to any one of Supplementary Notes 1 to 11, including a laminated film in which a silicon oxide film and a silicon nitride film are alternately laminated.

[0102] (Supplementary Note 13) The opening of the mask is formed by plasma etching, and the substrate processing method according to any one of Supplementary Notes 1 to 12.

[0103] (Supplementary Note 14) A substrate processing system including a substrate support portion disposed in a chamber, a plasma generation portion, and a control portion, The control portion is (a) Control for providing a substrate including a film to be etched and a mask on the film to be etched to the substrate support portion, the mask including sidewalls defining at least one opening, the control, and (b) Control for generating plasma from a processing gas containing carbon and hydrogen by the plasma generation portion and selectively forming an additional mask containing carbon on the mask, and (c) Control for generating plasma from an etching gas by the plasma generation portion and etching the film to be etched, and a substrate processing system that executes the control.

[0104] (Supplementary Note 15) The substrate processing system is A plurality of the chambers, and A transfer module capable of transferring a substrate in a vacuum atmosphere with respect to the plurality of chambers. The substrate processing system according to appended claim 14, wherein the control unit executes the controls of (a), (b), and (c) while maintaining a vacuum atmosphere using any one of the plurality of chambers.

[0105] In the above exemplary embodiments, the substrate processing method and the substrate processing system can be variously modified without departing from the scope and spirit of the present disclosure. For example, within the scope of the ordinary creative ability of those skilled in the art, some components in one embodiment can be added to other embodiments. Also, some components in one embodiment can be replaced with corresponding components in other embodiments.

Description of Reference Numerals

[0106] 1... Plasma processing apparatus, 2... Control unit, 10... Plasma processing chamber, 11... Substrate support unit, 12... Plasma generation unit, MK... Mask, OP1... Opening, U1... Upper surface, S1... Side wall, SF... Stacked film, UF... Underlayer film, MK1... Additional mask, W... Substrate

Claims

1. (a) A step of providing a substrate including an etching target film and a mask on the etching target film, wherein the mask includes sidewalls defining at least one opening, the step and, (b) A step of selectively forming an additional mask containing carbon on the mask using plasma generated from a processing gas containing carbon and hydrogen; and, (c) A step of etching the etching target film using plasma generated from an etching gas, the substrate processing method comprising:

2. The substrate processing method according to claim 1, wherein the step (b) is performed after the step (a).

3. The substrate in the step (a) includes a first film on the mask, (d) The substrate processing method according to claim 2, further comprising a step of removing the first film between the step (a) and the step (b).

4. The substrate processing method according to claim 2, wherein a plurality of cycles including the step (b) and the step (c) in this order are performed.

5. The substrate processing method according to claim 1, wherein the step (c) is performed after the step (a), and then a cycle including the step (b) and the step (c) in this order is performed one or more times.

6. The substrate processing method according to claim 1, wherein the mask has a thickness of 10 μm or less.

7. The substrate processing method according to claim 1, wherein the mask includes at least one selected from the group consisting of a carbon-containing film, a silicon-containing film, and a metal-containing film.

8. The substrate processing method according to claim 1, wherein the additional mask has a thickness of 0.2 μm or more.

9. The substrate processing method according to claim 1, wherein the additional mask has a thickness of 2 μm or less.

10. The substrate processing method according to claim 1, wherein the additional mask includes an amorphous carbon film.

11. The substrate processing method according to claim 1, wherein the etching target film includes a laminated film including two or more different silicon-containing films.

12. The substrate processing method according to claim 1, wherein the etching target film includes a laminated film in which a silicon oxide film and a silicon nitride film are alternately laminated.

13. The substrate processing method according to claim 1, wherein the opening of the mask is formed by plasma etching.

14. A substrate processing system including a substrate support portion disposed in a chamber, a plasma generation portion, and a control portion, The control unit is, Control for providing a substrate including an etching target film and a mask on the etching target film to a substrate support portion, the mask including sidewalls defining at least one opening, the control, and Control for generating a plasma from a processing gas containing carbon and hydrogen by a plasma generation unit and selectively forming an additional mask containing carbon on the mask, and Control for generating a plasma from an etching gas by a plasma generation unit and etching the etching target film, a substrate processing system that executes.

15. A plurality of the chambers, and A transfer module capable of transferring a substrate in a vacuum atmosphere with respect to the plurality of chambers, and The control unit executes the controls of (a), (b), and (c) while maintaining a vacuum atmosphere using any one of the plurality of chambers. The substrate processing system according to claim 14.

Images