Etching method and plasma treatment device

Abstract

This etching method comprises: (a) a step for providing a substrate, the substrate including a first region and a second region; (b) a step for forming a deposit on the first region by means of first plasma generated from a first treatment gas; (c) a step for modifying the deposit by irradiating the deposit with electron beams, simultaneously with (b) or after (b); and (d) a step for etching the second region by means of second plasma generated from a second treatment gas, in a state in which the irradiation with electron beams is stopped, after (c).

Description

Etching method and plasma processing apparatus

[0001] SUMMARY OF THE INVENTION Exemplary embodiments of the present disclosure relate to an etching method and a plasma processing apparatus.

[0002] Patent Document 1 discloses a method for monitoring and controlling a process for surface modification of a layer formed on a substrate using plasma. In this method, a surface modification gas is flowed into a plasma processing chamber of a plasma processing system. A plasma is generated in the plasma processing chamber to initiate the surface modification process of the layer formed on the substrate. In the surface modification process, resist cure modification is performed using an electron beam.

[0003] Special table 2020-515063 publication

[0004] The present disclosure provides an etching method and a plasma processing apparatus that can improve the etching resistance of deposits formed on a substrate.

[0005] In one exemplary embodiment, an etching method includes: (a) providing a substrate, the substrate including a first region and a second region; (b) forming a deposit on the first region using a first plasma generated from a first process gas; (c) simultaneously with or after (b), irradiating the deposit with an electron beam to modify the deposit; and (d) after (c), etching the second region using a second plasma generated from a second process gas while the irradiation of the electron beam is stopped.

[0006] According to one exemplary embodiment, an etching method and a plasma processing apparatus are provided that can improve the etching resistance of deposits formed on a substrate.

[0007] FIG. 1 is a diagram illustrating an example of the configuration of a plasma processing system. FIG. 2 is a diagram illustrating an example of the configuration of a capacitively coupled plasma processing apparatus. FIG. 3 is a flowchart of an etching method according to an exemplary embodiment. FIG. 4 is a partial enlarged view of an example substrate to which the method of FIG. 3 can be applied. FIG. 5 is a partial enlarged cross-sectional view of an example substrate relating to each step of the etching method according to an exemplary embodiment. FIG. 6 is a partial enlarged cross-sectional view of an example substrate relating to each step of the etching method according to an exemplary embodiment. FIG. 7 is a partial enlarged cross-sectional view of an example substrate relating to each step of the etching method according to an exemplary embodiment. FIG. 8 is a partial enlarged cross-sectional view of an example substrate relating to each step of the etching method according to an exemplary embodiment. FIG. 9 is a timing chart relating to the etching method according to an exemplary embodiment. FIG. 10 is a timing chart relating to the etching method according to another exemplary embodiment. FIG. 11 is a timing chart relating to the etching method according to another exemplary embodiment. FIG. 12 is a timing chart relating to the etching method according to another exemplary embodiment. FIG. 13 is a timing chart relating to the etching method according to another exemplary embodiment. FIG. 14 is a diagram illustrating an example of the configuration of a plasma processing apparatus including an electron beam irradiation source. Fig. 15 is a diagram for explaining another example of the configuration of a plasma processing apparatus including an electron beam irradiation source. Fig. 16 is a flowchart of an etching method according to another exemplary embodiment. Fig. 17 is a partial enlarged cross-sectional view of an example substrate relating to each step of the etching method according to another exemplary embodiment. Fig. 18 is a partial enlarged cross-sectional view of an example substrate relating to each step of the etching method according to another exemplary embodiment. Fig. 19 is a partial enlarged cross-sectional view of an example substrate relating to each step of the etching method according to another exemplary embodiment. Fig. 20 is a partial enlarged cross-sectional view of an example substrate relating to each step of the etching method according to another exemplary embodiment.

[0008] Various exemplary embodiments will be described in detail below with reference to the drawings, in which the same or equivalent parts are designated by the same reference numerals.

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

[0010] The plasma generating unit 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma generated in the plasma processing space may be capacitively coupled plasma (CCP), inductively coupled plasma (ICP), electron-cyclotron-resonance plasma (ECR plasma), helicon wave plasma (HWP), surface wave plasma (SWP), or the like. Various types of plasma generators may be used, including alternating current (AC) plasma generators and direct current (DC) plasma generators. In one embodiment, the AC signal (AC power) used in the AC plasma generator has a frequency in the range of 100 kHz to 10 GHz. Thus, AC signals include radio frequency (RF) signals and microwave signals. In one embodiment, the RF signal has a frequency in the range of 100 kHz to 150 MHz.

[0011] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to perform various processes described in this disclosure. The control unit 2 may be configured to control each element of the plasma processing apparatus 1 to perform various processes described herein. In one embodiment, part or all of the 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 may be implemented by, for example, a computer 2a. The processing unit 2a1 may be configured to read a program from the storage unit 2a2 and execute the read program to perform various control operations. This program may be stored in the storage unit 2a2 in advance or may be acquired via a medium when needed. The acquired program is stored in the storage unit 2a2 and read from the storage unit 2a2 by the processing unit 2a1 for execution. The medium may be various storage media readable by the computer 2a or a communication line connected to the communication interface 2a3. The 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).

[0012] The following describes a configuration example of a capacitively coupled plasma processing apparatus as an example of the plasma processing apparatus 1. Fig. 2 is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus.

[0013] The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply 20, a power supply 30, and an exhaust system 40. The plasma processing apparatus 1 also includes a substrate support 11 and a gas inlet. The gas inlet is configured to introduce at least one process gas into the plasma processing chamber 10. The gas inlet includes a showerhead 13. The substrate support 11 is disposed within the plasma processing chamber 10. The showerhead 13 is disposed above the substrate support 11. In one embodiment, the showerhead 13 forms at least a portion of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the showerhead 13, a sidewall 10a of the plasma processing chamber 10, and the substrate support 11. The plasma processing chamber 10 is grounded. The showerhead 13 and the substrate support 11 are electrically insulated from the housing of the plasma processing chamber 10.

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

[0015] In one embodiment, the main body 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive member. The conductive member of the base 1110 can function as a lower electrode. The electrostatic chuck 1111 is disposed on the base 1110. The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic electrode 1111b disposed within the ceramic member 1111a. The ceramic member 1111a has a central region 111a. In one embodiment, the ceramic member 1111a also has an annular region 111b. Note that the annular region 111b may also be provided by another member surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member. In this case, the ring assembly 112 may be disposed on the annular electrostatic chuck or the annular insulating member, or may be disposed on both the electrostatic chuck 1111 and the annular insulating member. Furthermore, at least one RF / DC electrode coupled to an RF power supply 31 and / or a DC power supply 32, which will be described later, may be disposed within 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, which will be 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 multiple lower electrodes. Furthermore, the electrostatic electrode 1111b may function as a lower electrode. Therefore, the substrate support 11 includes at least one lower electrode.

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

[0017] The substrate support 11 may also include a temperature adjustment module configured to adjust at least one of the electrostatic chuck 1111, the ring assembly 112, and the substrate to a target temperature. The temperature adjustment module may include a heater, a heat transfer medium, a flow passage 1110a, or a combination thereof. A heat transfer fluid such as brine or a gas flows through the flow passage 1110a. In one embodiment, the flow passage 1110a is formed in the base 1110, and one or more heaters are disposed in the ceramic member 1111a of the electrostatic chuck 1111. The substrate support 11 may also include a heat transfer gas supply configured to supply a heat transfer gas to a gap between the backside of the substrate W and the central region 111a.

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

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

[0020] 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. This generates a plasma from at least one processing gas supplied to the plasma processing space 10s. Therefore, the RF power supply 31 can function as at least a part of the plasma generation unit 12. Furthermore, by supplying a bias RF signal to the at least one lower electrode, a bias potential is generated on the substrate W, thereby attracting ion components in the formed plasma to the substrate W.

[0021] 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 multiple 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.

[0022] The second RF generator 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 60 MHz. In one embodiment, the second RF generator 31b may be configured to generate multiple bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to at least one lower electrode. In various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0023] The power supply 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 the at least one lower electrode and configured to generate a first DC signal. The generated first DC signal is applied to the at least one lower electrode. In one embodiment, the second DC generator 32b is connected to the 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.

[0024] 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 rectangular, trapezoidal, triangular, or combination thereof pulse waveform. In one embodiment, a waveform generator for generating the 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 either positive or negative polarity. Furthermore, the sequence of voltage pulses may include one or more positive voltage pulses and one or more negative voltage pulses within one period. The first and second DC generating units 32a and 32b may be provided in addition to the RF power supply 31, or the first DC generating unit 32a may be provided instead of the second RF generating unit 31b.

[0025] The exhaust system 40 may be connected to, for example, a gas exhaust port 10e provided at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure in the plasma processing space 10s is regulated by the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0026] Fig. 3 is a flowchart of an etching method according to one example embodiment. The etching method MT1 shown in Fig. 3 (hereinafter referred to as "method MT1") can be performed by the plasma processing apparatus 1 of the above embodiment. The method MT1 may also be performed by a plasma processing apparatus different from the plasma processing apparatus 1. The method MT1 can be applied to the substrate W of Fig. 4.

[0027] FIG. 4 is a cross-sectional view of an example substrate to which the method of FIG. 3 can be applied. As shown in FIG. 4, in one embodiment, the substrate W includes a first region R1 and a second region R2. The first region R1 may be provided on the second region R2. The first region R1 may be a mask. The first region R1 has at least one opening OP. The at least one opening OP may be a hole or a slit. The first region R1 may have multiple openings OP. The second region R2 may be a film to be etched. The substrate W may further include an underlayer region UR. The underlayer region UR may be located below the second region R2. Each of the first region R1, the second region R2, and the underlayer region UR may be a film.

[0028] The first region R1 may include a metal, a metal hard mask, or carbon-doped tungsten or titanium nitride.

[0029] The second region R2 may include a dielectric film. The second region R2 may include a low-k film. The low-k film may have a relative dielectric constant of 3.8 or less. The second region R2 may include silicon and oxygen. The second region R2 may include silicon oxide (SiO ２ ) or SiOCH.

[0030] Method MT1 will be described below with reference to FIGS. 3 to 8, taking as an example a case where method MT1 is applied to a substrate W using the plasma processing apparatus 1 of the above embodiment. FIGS. 5 to 8 are enlarged cross-sectional views of an example substrate relating to each step of an etching method according to one exemplary embodiment. When the plasma processing apparatus 1 is used, method MT1 can be performed in the plasma processing apparatus 1 by controlling each part of the plasma processing apparatus 1 with a control unit 2. In method MT1, a substrate W on a substrate support 11 disposed in a plasma processing chamber 10 is processed, as shown in FIG. 2.

[0031] 3, the method MT1 may include steps ST1 to ST6. Steps ST1 to ST6 may be performed in order. Step ST4 may be performed simultaneously with step ST3, after step ST3, or simultaneously with step ST3 and after step ST4. The method MT1 may not include at least one of step ST2 and step ST6.

[0032] 4 is provided on the substrate support 11 in the plasma processing chamber 10. Each step of the method MT1 performed after the step ST1 is performed in a state where the substrate W is placed on the substrate support 11.

[0033] (Step ST2) In step ST2, as shown in FIG. 5, a fourth plasma PL4 is generated from a fourth process gas. The fourth process gas may be a gas having deposition properties. The fourth process gas may contain fluorine and carbon. The fourth process gas may contain at least one of a fluorocarbon gas and a hydrofluorocarbon gas. Examples of the fluorocarbon gas include C ４ F ８ The fourth process gas may further include one or more of a nitrogen-containing gas (e.g., nitrogen gas), an oxygen-containing gas (e.g., oxygen gas), or a noble gas (e.g., Ar gas). In step ST2, a fourth plasma PL4 is ignited in the plasma processing chamber 10, and radicals are generated from the fourth process gas. Step ST2 may be performed while irradiation with an electron beam EB (see FIG. 7 ), which will be described later, is stopped. Step ST2 may be performed while irradiation with the electron beam EB is ongoing.

[0034] Step ST2 may be performed as follows: The gas supply unit 20 supplies a fourth process gas into the plasma processing chamber 10. The control unit 2 controls the gas supply unit 20 and the plasma generation unit 12 so that a fourth plasma PL4 is generated from the fourth process gas.

[0035] In step ST2, the power level of the source radio frequency power used to generate the fourth plasma PL4 may be higher than the power level of the source radio frequency power used to generate the first plasma PL1 in step ST3. In step ST2, an electric bias may not be supplied to the substrate support 11 that supports the substrate W. The control unit 2 controls the power supply 30 to adjust the level of the source radio frequency power and the level of the electric bias.

[0036] (Step ST3) In step ST3, as shown in FIG. 6 , a deposit DP is formed on the first region R1 by a first plasma PL1 generated from a first processing gas. The deposit DP may be formed on the second region R2. The first processing gas may be the same as the fourth processing gas. The deposit DP may contain at least one of carbon or fluorine. The deposit DP may contain at least one of a carbon-carbon bond (C-C bond) or a carbon-fluorine bond (C-F bond). The deposit DP may further contain oxygen. The deposit DP may contain a carbon-oxygen bond (C=O bond or C-O bond). Step ST3 may be performed while irradiation with an electron beam EB (see FIG. 7 ), which will be described later, is stopped. Step ST3 may be performed while irradiation with the electron beam EB is ongoing.

[0037] Step ST3 may be performed as follows: The gas supply unit 20 supplies a first processing gas into the plasma processing chamber 10. The control unit 2 controls the gas supply unit 20 and the plasma generation unit 12 so that a first plasma PL1 is generated from the first processing gas.

[0038] In step ST3, the power level of the source radio frequency power used to generate the first plasma PL1 may be higher than the power level of the source radio frequency power used to generate the second plasma PL2 in step ST5. In step ST3, an electric bias may not be supplied to the substrate support 11 that supports the substrate W. The control unit 2 controls the power supply 30 to adjust the level of the source radio frequency power and the level of the electric bias.

[0039] (Step ST4) In step ST4, as shown in FIG. 7 , the deposit DP is modified by irradiating it with an electron beam EB. As a result, a deposit MDP is produced from the deposit DP. If the deposit DP contains carbon, elements other than carbon (e.g., fluorine or oxygen) can be extracted from the deposit DP by the energy of the electron beam EB. C—F bonds, C═O bonds, or C—O bonds in the deposit DP can be dissociated. Therefore, in the deposit MDP obtained in step ST4, more carbon-carbon bonds (C—C bonds, C═C bonds, or C≡C bonds) with high bond energy can be formed than in the deposit DP.

[0040] In step ST4, a third plasma PL3 may be generated from a third process gas. The third process gas may be the same as the fourth process gas. The electron beam EB may be generated by applying a negative voltage to an upper electrode UE provided above the substrate W. The upper electrode UE may be included in the shower head 13 of the plasma processing apparatus 1 (see FIG. 2). The negative voltage may be applied from a power supply 30. When a negative voltage is applied to the upper electrode UE, positive ions (e.g., Ar ions) in the third plasma PL3 collide with the upper electrode UE. Secondary electrons generated by sputtering become the electron beam EB and are irradiated onto the substrate W. In this case, the upper electrode UE and the power supply 30 constitute an electron beam irradiation source for the electron beam EB.

[0041] Step ST4 may be performed as follows: The gas supply unit 20 supplies a third process gas into the plasma processing chamber 10. The control unit 2 controls the gas supply unit 20, the plasma generation unit 12, and the electron beam irradiation source so that a third plasma PL3 is generated from the third process gas and the substrate W is irradiated with an electron beam EB.

[0042] In step ST4, the power level of the source radio frequency power used to generate the third plasma PL3 may be equal to or greater than the power level of the source radio frequency power used to generate the second plasma PL2 in step ST5. The level of the electric bias supplied to the substrate support 11 that supports the substrate W in step ST4 may be lower than the level of the electric bias supplied to the substrate support 11 that supports the substrate W in step ST5. The control unit 2 controls the power supply 30 to adjust the level of the source radio frequency power and the level of the electric bias.

[0043] (Process ST5) In process ST5, as shown in FIG. 8 , the second region R2 is etched with a second plasma PL2 generated from a second processing gas while the irradiation of the electron beam EB is stopped. This allows a recess RS to be formed in the second region R2. The recess RS corresponds to the opening OP in the first region R1. In process ST5, voltage does not need to be applied to the upper electrode UE to stop the irradiation of the electron beam EB. In this case, foreign matter resulting from silicon generated by sputtering of the upper electrode UE can be suppressed. Furthermore, the silicon can be prevented from scavenging and exhausting fluorine in the second plasma PL2. Process ST5 may be performed while the electron beam EB is being irradiated.

[0044] Step ST5 may be performed as follows: The gas supply unit 20 supplies a second process gas into the plasma processing chamber 10. The control unit 2 controls the gas supply unit 20 and the plasma generation unit 12 so that a second plasma PL2 is generated from the second process gas.

[0045] The level of the electric bias supplied to the substrate support 11 that supports the substrate W in step ST5 may be higher than the level of the electric bias supplied to the substrate support 11 that supports the substrate W in step ST3 or step ST4. The control unit 2 controls the power supply 30 to adjust the level of the source high-frequency power and the level of the electric bias.

[0046] (Step ST6) In step ST6, a cycle CY including steps ST2 to ST5 is repeated. The cycle CY does not have to include step ST2. The time for each cycle CY may be 1 second or less, or 1 millisecond or less. Increasing the number of cycles CY deepens the recesses RS formed in the second region R2.

[0047] Step ST6 may be performed as follows: The control unit 2 controls the gas supply unit 20, the plasma generation unit 12, and the electron beam irradiation source so as to repeat a cycle CY including steps ST2 to ST5.

[0048] According to the etching method MT1, the etching resistance of the deposit MDP is improved by irradiation with the electron beam EB in step ST4. Therefore, in step ST5, reduction of the deposit MDP due to etching can be suppressed. As a result, reduction of the first region R1 can also be suppressed.

[0049] 9 is a timing chart relating to an etching method according to one example embodiment. This timing chart relates to steps ST2 to ST5 of method MT1. One cycle CY includes periods P1 to P4. Period P2 is the period following period P1. Period P3 is the period following period P2. Period P4 is the period following period P3. Period P4 of one cycle CY is followed by period P1 of the next cycle CY. In the timing chart of FIG. 9, step ST2 is performed in period P1. Steps ST3 and ST4 are simultaneously performed in period P2. Step ST5 is performed in period P4.

[0050] During period P1 (step ST2), the negative voltage NV applied to the upper electrode UE in FIG. 7 is 0 V. That is, during period P1, no negative voltage is applied to the upper electrode UE. During period P1, the power level of the source high frequency power RF used to generate the fourth plasma PL4 is a level LV13 higher than 0 W. During period P1, the level of the electric bias EBS supplied to the substrate support member 11 is 0. That is, during period P1, no electric bias EBS is supplied to the substrate support member 11. During period P1, the fourth plasma PL4 is ignited.

[0051] In this specification, when the electric bias EBS is a bias high frequency power, the level of the electric bias EBS is the power level of the bias high frequency power. When the electric bias EBS includes a voltage pulse, the level of the electric bias EBS is the absolute value of the negative voltage level of the voltage pulse.

[0052] During period P2 (steps ST3 and ST4), the absolute value of the negative voltage NV applied to the upper electrode UE in FIG. 7 is at level LV31, which is higher than 0 V. During period P2, the power level of the source high frequency power RF used to generate the first plasma PL1 is at level LV12, which is higher than 0 W. Level LV12 is lower than level LV13. During period P2, the level of the electric bias EBS supplied to the substrate support 11 is 0. That is, during period P2, no electric bias EBS is supplied to the substrate support 11. During period P2, the formation and modification of the deposit DP proceed simultaneously.

[0053] During period P3, the negative voltage NV applied to the upper electrode UE in FIG. 7 is 0 V. That is, during period P3, no negative voltage is applied to the upper electrode UE. During period P3, the power level of the source radio frequency power RF used to generate the third plasma PL3 is a level LV11 higher than 0 W. The level LV11 is lower than the level LV12. During period P3, the level of the electrical bias EBS supplied to the substrate support 11 is a level LV21 higher than 0 W.

[0054] During period P4 (step ST5), the negative voltage NV applied to the upper electrode UE in FIG. 7 is 0 V. That is, during period P4, no negative voltage is applied to the upper electrode UE. During period P4, the power level of the source high frequency power RF used to generate the second plasma PL2 is a level LV11 higher than 0 W. During period P4, the level of the electrical bias EBS supplied to the substrate support 11 is a level LV22 higher than 0. The level LV22 is higher than the level LV21. During period P4, the second region R2 is etched.

[0055] 10 is a timing chart related to an etching method according to another exemplary embodiment. The timing chart of FIG. 10 is the same as the timing chart of FIG. 9 except for the following points. In the timing chart of FIG. 10, step ST4 is performed in period P3 in addition to period P2. In period P3, the absolute value of the negative voltage NV applied to the upper electrode UE of FIG. 7 is a level LV31 that is higher than 0 V.

[0056] 11 is a timing chart related to an etching method according to another exemplary embodiment. The timing chart of FIG. 11 is the same as the timing chart of FIG. 9 except for the following points. In the timing chart of FIG. 11, process ST4 is not performed in period P2, but is performed in period P3. In period P2, the negative voltage NV applied to the upper electrode UE of FIG. 7 is 0 V. That is, no negative voltage is applied to the upper electrode UE in period P2. In period P3, the absolute value of the negative voltage NV applied to the upper electrode UE of FIG. 7 is a level LV31 that is higher than 0 V.

[0057] 12 is a timing chart related to an etching method according to another exemplary embodiment. The timing chart of FIG. 12 is the same as the timing chart of FIG. 9 except for the following points. In the timing chart of FIG. 12, a negative voltage NV is applied to the upper electrode UE of FIG. 7 during periods P1, P3, and P4. The absolute value of the negative voltage NV is level LV32. Level LV32 is higher than 0 V and lower than level LV31. Level LV32 may be less than half of level LV31. Steps ST2 and ST5 are performed while irradiating with an electron beam EB.

[0058] FIG. 13 is a timing chart related to an etching method according to another exemplary embodiment. The timing chart of FIG. 13 is the same as the timing chart of FIG. 12 except for the following points. In the timing chart of FIG. 13, a pulsed negative voltage NV is applied to the upper electrode UE of FIG. 7 during periods P2 and P3. During periods P2 and P3, the maximum absolute value of the negative voltage NV is level LV31, and the minimum absolute value of the negative voltage NV is level LV32. At the beginning of period P2, the absolute value of the negative voltage NV is level LV31. At the end of period P3, the absolute value of the negative voltage NV is level LV32. The period of the pulsed negative voltage NV may be 1 second or less, or 100 milliseconds or less. Steps ST3 and ST4 are performed under a state in which the electron beam EB is irradiated in a pulsed manner.

[0059] In the timing chart of Figure 13, pulsed source radio frequency power RF is supplied during periods P2 and P3. The pulsed source radio frequency power RF is synchronized with the pulsed negative voltage NV. During periods P2 and P3, the maximum power level of the source radio frequency power RF is level LV12, and the minimum power level of the source radio frequency power RF is level LV11. At the beginning of period P2, the power level of the source radio frequency power RF is level LV12. At the end of period P3, the power level of the source radio frequency power RF is level LV11.

[0060] In the timing chart of Fig. 13, a pulsed electric bias EBS is supplied in periods P2 and P3. The pulsed electric bias EBS is synchronized with the pulsed negative voltage NV and the pulsed source radio frequency power RF. In periods P2 and P3, the maximum level of the electric bias EBS is level LV21, and the minimum level of the electric bias EBS is 0. At the beginning of period P2, the level of the electric bias EBS is 0. At the end of period P3, the level of the electric bias EBS is level LV21.

[0061] 13, the period of the negative voltage NV level LV31 corresponds to the period of the source radio frequency power RF level LV12, and the period of the negative voltage NV level LV32 corresponds to the period of the source radio frequency power RF level LV11, but this is not limiting. For example, the period of the negative voltage NV level LV31 may correspond to the period of the source radio frequency power RF level LV11, and the period of the negative voltage NV level LV32 may correspond to the period of the source radio frequency power RF level LV12. Alternatively, the period of the negative voltage NV level LV31 may be offset from the period of the source radio frequency power RF level LV12 or level LV11. The period of the negative voltage NV level LV32 may be offset from the period of the source radio frequency power RF level LV12 or level LV11.

[0062] Here, the power levels of the source radio frequency power RF in each of the periods P1, P2, P3, and P4 are expressed as L ＲＦ１ , L ＲＦ２ , L ＲＦ３ , L ＲＦ４ The levels of the electric bias EBS in each of the periods P1, P2, P3, and P4 are represented as L ＥＢ１ , L ＥＢ２ , L ＥＢ３ , L ＥＢ４ The power level of the source radio frequency power RF and the level of the electrical bias EBS in each step of the method MT1 are not limited to the above-mentioned examples.

[0063] For example, the power level of the source radio frequency power RF may satisfy any one of the following (A1) to (A4), and the level of the electrical bias EBS may satisfy any one of the following (A5) to (A10): (A1) 0≦L ＲＦ４ <L ＲＦ２ <L ＲＦ３ <L ＲＦ１ (A2) 0<L ＲＦ２ ≦L ＲＦ４ <L ＲＦ３ <L ＲＦ１ (A3) 0<L ＲＦ２ <L ＲＦ３ ≦L ＲＦ４ <L ＲＦ１ (A4) 0<LＲＦ２ <L ＲＦ３ <L ＲＦ１ ≦L ＲＦ４ (A5) 0≦L ＥＢ１ ≦L ＥＢ２ ≦L ＥＢ３ <L ＥＢ４ (A6) 0≦L ＥＢ２ ≦L ＥＢ１ ≦L ＥＢ３ <L ＥＢ４ (A7) 0≦L ＥＢ３ ≦L ＥＢ１ ≦L ＥＢ２ <L ＥＢ４ (A8) 0≦L ＥＢ３ ≦L ＥＢ２ ≦L ＥＢ１ <L ＥＢ４ (A9) 0≦L ＥＢ１ ≦L ＥＢ３ ≦L ＥＢ２ <L ＥＢ４ (A10) 0≦L ＥＢ２ ≦L ＥＢ３ ≦L ＥＢ１ <L ＥＢ４

[0064] Alternatively, the power level of the source radio frequency power RF may satisfy any one of the following (B1) to (B4), and the level of the electrical bias EBS may satisfy any one of the following (B5) to (B10): (B1) 0≦L ＲＦ４ <L ＲＦ２ <L ＲＦ１ <L ＲＦ３ (B2) 0<L ＲＦ２ ≦L ＲＦ４ <L ＲＦ１ <L ＲＦ３ (B3) 0<L ＲＦ２ <L ＲＦ１ ≦L ＲＦ４ <L ＲＦ３ (B4) 0<L ＲＦ２ <L ＲＦ１ <L ＲＦ３ ≦L ＲＦ４ (B5) 0≦L ＥＢ１ ≦L ＥＢ２ ≦L ＥＢ３ <L ＥＢ４ (B6) 0≦L ＥＢ２ ≦L ＥＢ１ ≦L ＥＢ３ <L ＥＢ４(B7) 0≦L ＥＢ３ ≦L ＥＢ１ ≦L ＥＢ２ <L ＥＢ４ (B8) 0≦L ＥＢ３ ≦L ＥＢ２ ≦L ＥＢ１ <L ＥＢ４ (B9) 0≦L ＥＢ１ ≦L ＥＢ３ ≦L ＥＢ２ <L ＥＢ４ (B10) 0≦L ＥＢ２ ≦L ＥＢ３ ≦L ＥＢ１ <L ＥＢ４

[0065] Alternatively, the power level of the source radio frequency power RF may satisfy any one of the following (C1) to (C4), and the level of the electrical bias EBS may satisfy any one of the following (C5) to (C7): (C1) 0≦L ＲＦ４ <L ＲＦ３ ≦L ＲＦ２ <L ＲＦ１ (C2) 0<L ＲＦ３ ≦L ＲＦ４ ≦L ＲＦ２ <L ＲＦ１ (C3) 0<L ＲＦ３ ≦L ＲＦ２ ≦L ＲＦ４ <L ＲＦ１ (C4) 0<L ＲＦ３ ≦L ＲＦ２ <L ＲＦ１ ≦L ＲＦ４ (C5) 0≦L ＥＢ１ <L ＥＢ３ <L ＥＢ３ <L ＥＢ４ (C6) 0<L ＥＢ３ ≦L ＥＢ１ <L ＥＢ３ <L ＥＢ４ (C7) 0<L ＥＢ３ <L ＥＢ３ ≦L ＥＢ１ <L ＥＢ４

[0066] FIG. 14 is a diagram illustrating an example of the configuration of a plasma processing apparatus including an electron beam irradiation source. The plasma processing apparatus shown in FIG. 14 further includes an electron beam irradiation source ES in addition to the configuration of the plasma processing apparatus 1 shown in FIG. 2. The electron beam irradiation source ES is, for example, an electron gun. The electron beam irradiation source ES is attached to the plasma processing chamber 10 above the substrate W. The electron beam irradiation source ES is configured to irradiate the substrate W in the plasma processing chamber 10 with an electron beam EB. The control unit 2 ( FIG. 2 ) may be configured to control the electron beam irradiation source ES to emit the electron beam EB in a pulsed (intermittent) manner by repeatedly turning the electron beam EB on and off. This allows the electron beam EB to be irradiated onto the substrate W in step ST4, and the irradiation of the electron beam EB to be stopped in other steps (step ST2, step ST3, or step ST5).

[0067] FIG. 15 is a diagram illustrating another exemplary configuration of a plasma processing apparatus equipped with an electron beam irradiation source. The plasma processing apparatus illustrated in FIG. 15 further includes an electron beam irradiation source ES and a shutter ST in addition to the configuration of the plasma processing apparatus 1 illustrated in FIG. 2 . The shutter ST is disposed between the electron beam irradiation source ES and the plasma processing chamber 10. The shutter ST is, for example, a MEMS (Micro Electro Mechanical Systems) shutter. The shutter ST includes a plate-shaped member PT1 having an aperture AP1 for transmitting the electron beam EB and a plate-shaped member PT2 having an aperture AP2 for transmitting the electron beam EB. The plate-shaped members PT1 and PT2 are relatively movable between a first position where the apertures AP1 and AP2 overlap each other and a second position where the apertures AP1 and AP2 do not overlap each other. At the first position, the electron beam EB emitted from the electron beam irradiation source ES reaches the plasma processing chamber 10. At the second position, the electron beam EB emitted from the electron beam irradiation source ES is blocked by the shutter ST and does not reach the plasma processing chamber 10. The shutter ST can be repeatedly opened and closed periodically. The control unit 2 ( FIG. 2 ) may be configured to control the opening and closing of the shutter ST so that the electron beam EB is irradiated onto the substrate W in pulses (intermittently). In this case, the electron beam EB does not need to be emitted from the electron beam irradiation source ES in pulses, and may be emitted continuously from the electron beam irradiation source ES. By using the electron beam irradiation source ES and the shutter ST, the electron beam EB can be irradiated onto the substrate W in step ST4 and the irradiation of the electron beam EB can be stopped in other steps (step ST2, step ST3, or step ST5).

[0068] 14 and 15, the electron beam EB can be generated without applying a negative voltage to the upper electrode UE. The plasma processing apparatus of FIG. 14 and 15 can perform the method MT1 in accordance with the timing charts of FIG. 9 to FIG. 13, for example.

[0069] An etching method according to another exemplary embodiment will be described below with reference to FIGS. 16 to 20. FIG. 16 is a flowchart of the etching method according to another exemplary embodiment. FIGS. 17 to 20 are enlarged cross-sectional views of an example substrate relating to each step of the etching method according to another exemplary embodiment. The etching method shown in FIG. 16 (hereinafter referred to as "Method MTA") will be described below, taking as an example a case where plasma processing apparatus 1 is used. Note that Method MTA may be performed using a plasma processing apparatus different from Plasma Processing Apparatus 1. Method MTA may also be performed using the plasma processing apparatuses of FIGS. 14 and 15.

[0070] The method MTA is applied to a substrate W shown in Fig. 17. As shown in Fig. 17, the substrate W includes an underlying region UR, a film EF, a metal hard mask MHM, a silicon oxide film OXM, an organic film OF, a silicon-containing film ARF, and a resist mask PR. The metal hard mask MHM is an example of the first region R1 in Fig. 4. The film EF is an example of the second region R2 in Fig. 4.

[0071] The underlayer region UR is, for example, an etching stop layer. The underlayer region UR may have a layered structure including an aluminum oxide film and a SiCN film. The film EF is provided on the underlayer region UR. The film EF is a dielectric film and may contain silicon and oxygen. In one embodiment, the film EF may include a low-k film LKF. The film EF may have a layered structure including a low-k film LKF and a silicon oxide film OXF. The low-k film LKF may be a SiOCH film.

[0072] The metal hard mask MHM is provided on the film EF. The metal hard mask MHM has a pattern that is transferred to the film EF by etching. That is, the metal hard mask MHM provides one or more openings. The metal hard mask MHM is made of, for example, titanium nitride. The metal hard mask MHM may also be made of other metal-containing materials.

[0073] A silicon oxide film OXM is provided on top of the metal hard mask MHM. An organic film OF is provided to cover the silicon oxide film OXM, the metal hard mask MHM, and the film EF. A silicon-containing film ARF is provided on the organic film OF. The silicon-containing film ARF may be an anti-reflective film. A resist mask PR is provided on the silicon-containing film ARF. The resist mask PR is patterned using a photolithography technique. The resist mask PR has one or more openings for forming recesses (e.g., trenches or holes) in the film EF in the portions exposed from the metal hard mask MHM.

[0074] 16 , the method MTA includes a step ST1. In step ST1 of the method MTA, similar to step ST1 of the method MT1, a substrate W (see FIG. 17 ) is provided on a substrate support 11 in the plasma processing chamber 10 of the plasma processing apparatus 1. The steps of the method MTA performed after step ST1 are performed in a state in which the substrate W is placed on the substrate support 11.

[0075] In the method MTA, step ST11 is performed after step ST1. In step ST11, the silicon-containing film ARF is etched. The pattern of the resist mask PR is transferred to the silicon-containing film ARF by step ST11. In step ST11, plasma is generated from an etching gas in the plasma processing chamber 10 to etch the silicon-containing film ARF. The etching gas used in step ST11 includes a fluorocarbon gas and a noble gas (e.g., Ar gas).

[0076] In process ST11, the control unit 2 controls the gas supply unit 20 to supply an etching gas into the plasma processing chamber 10. In process ST11, the control unit 2 controls the exhaust system 40 to set the pressure in the plasma processing chamber 10 to a designated pressure. In process ST11, the control unit 2 controls the power supply 30 to supply source radio frequency power RF to the radio frequency electrode to generate plasma from the etching gas. In process ST11, the control unit 2 may control the power supply 30 to supply an electrical bias EBS to the bias electrode.

[0077] Next, step ST12 is performed. In step ST12, the organic film OF is etched. In step ST11, the pattern of the silicon-containing film ARF is transferred to the organic film OF as shown in FIG. 18 . In step ST12, plasma is generated from an etching gas in the plasma processing chamber 10 to etch the organic film OF. The etching gas used in step ST12 contains an oxygen-containing gas (e.g., oxygen gas). Alternatively, the etching gas used in step ST12 may contain nitrogen gas and hydrogen gas.

[0078] In process ST12, the control unit 2 controls the gas supply unit 20 to supply an etching gas into the plasma processing chamber 10. In process ST12, the control unit 2 controls the exhaust system 40 to set the pressure in the plasma processing chamber 10 to a designated pressure. In process ST12, the control unit 2 controls the power supply 30 to supply source radio frequency power RF to the radio frequency electrode to generate plasma from the etching gas. In process ST12, the control unit 2 may control the power supply 30 to supply an electrical bias EBS to the bias electrode.

[0079] Next, step ST13 is performed. In step ST13, the film EF is etched. In step ST13, steps ST2 to ST6 (see FIG. 3) in the above-described method MT1 are performed. In step ST13, the pattern of the organic film OF is transferred to the film EF, and recesses are formed in the film EF, as shown in FIG.

[0080] Next, step ST14 is performed. In step ST14, the organic film OF is removed. In step ST14, plasma is generated from an ashing gas in the plasma processing chamber 10 to remove the organic film OF. The ashing gas used in step ST14 includes an oxygen-containing gas (e.g., oxygen gas and / or CO gas).

[0081] In step ST14, the control unit 2 controls the gas supply unit 20 to supply an ashing gas into the plasma processing chamber 10. In step ST4, the control unit 2 controls the exhaust system 40 to set the pressure in the plasma processing chamber 10 to a designated pressure. In step ST4, the control unit 2 controls the power supply 30 to supply source radio frequency power RF to the radio frequency electrode to generate plasma from the etching gas.

[0082] Next, step ST15 is performed. In step ST15, the film EF is further etched so as to increase the depth of the recessed portion, as shown in Fig. 20. In step ST15, steps ST2 to ST6 (see Fig. 3) in the above-described method MT1 are performed.

[0083] According to the method MTA, similarly to the method MT1, the metal hard mask MHM is protected by the deposit MDP (see FIG. 7 ) during etching of the film EF in steps ST13 and ST15. Therefore, reduction of the metal hard mask MHM due to etching of the film EF is suppressed. Furthermore, according to the method MTA, even if the pattern of the resist mask PR is misaligned with the pattern of the metal hard mask MHM, it is possible to proceed with etching of the film EF while suppressing reduction of the metal hard mask MHM. If the pattern of the resist mask PR is misaligned with the pattern of the metal hard mask MHM, the silicon oxide film OXM may be exposed in step ST12. In this case, when the exposed silicon oxide film OXM is etched in step ST13, the metal hard mask MHM may be exposed and etched. Even in such cases, the metal hard mask MHM is protected by the deposit MDP.

[0084] Various experiments conducted to evaluate Method MT1 and Method MTA are described below, but the experiments described below are not intended to limit the present disclosure.

[0085] (First Experiment) In the first experiment, first, a substrate was provided on a substrate support in a chamber of a plasma processing apparatus (step ST1). The substrate had a titanium nitride film on its surface.

[0086] Next, a deposit containing carbon and fluorine was formed on the titanium nitride film by plasma generated from fluorocarbon gas (step ST3).

[0087] Next, a plasma was generated from Ar gas, and a negative voltage (-900 V) was applied to the upper electrode above the substrate. In this way, the substrate was irradiated with an electron beam generated by sputtering of the upper electrode (step ST4). The duration of step ST4 was 30 seconds.

[0088] Next, the substrate was treated with plasma for etching the silicon oxide film (step ST5).

[0089] (Second Experiment) In the second experiment, the same procedure as in the first experiment was carried out except that a negative voltage was not applied to the upper electrode in step ST4. In the second experiment, the deposit on the titanium nitride film was not irradiated with an electron beam.

[0090] (Third Experiment) In the third experiment, the same experiment as the first experiment was carried out except that step ST4 was not performed. In the third experiment, the deposit on the titanium nitride film was not irradiated with an electron beam.

[0091] (Experimental Results) The cross section of the substrate was observed before and after step ST5, and the amount of reduction in the thickness of the deposit due to step ST5 was measured. The amount of reduction in the thickness of the deposit in the first experiment was 11.3 nm. The amount of reduction in the thickness of the deposit in the second experiment was 16.3 nm. The amount of reduction in the thickness of the deposit in the third experiment was 16.1 nm.

[0092] Furthermore, the C-C bonds and C-F bonds in the deposits were measured by X-ray photoelectron spectroscopy (XPS). As a result, in the first experiment, the ratio of C-C bonds to C-F bonds (CC / CF ratio) near the surface of the deposits was high, at 1 or more. On the other hand, in the second and third experiments, the CC / CF ratio near the surface of the deposits was low, at less than 1.

[0093] From the above, it was found that when a deposit is irradiated with an electron beam, the CC / CF ratio in the vicinity of the surface of the deposit increases, and therefore the etching resistance of the deposit is improved.

[0094] Although various exemplary embodiments have been described above, the present invention is not limited to the above-described exemplary embodiments, and various additions, omissions, substitutions, and modifications may be made. Furthermore, elements in different embodiments may be combined to form other embodiments.

[0095] Various exemplary embodiments included in the present disclosure are now described in [E1] to [E17] below.

[0096] [E1] An etching method comprising: (a) providing a substrate, the substrate including a first region and a second region; (b) forming a deposit on the first region by a first plasma generated from a first process gas; (c) simultaneously with or after (b), irradiating the deposit with an electron beam to modify the deposit; and (d) after (c), etching the second region by a second plasma generated from a second process gas while the irradiation of the electron beam is stopped.

[0097] According to the above etching method, the etching resistance of the deposit is improved by irradiation with electron beams.

[0098] [E2] The etching method according to [E1], further comprising the step of: (e) repeating a cycle including the steps (b), (c), and (d).

[0099] [E3] The etching method according to [E1] or [E2], wherein the deposit contains at least one of carbon and fluorine.

[0100] [E4] The etching method according to any one of [E1] to [E3], wherein in (c), a third plasma is generated from a third process gas, and the electron beam is generated by applying a negative voltage to an upper electrode provided above the substrate.

[0101] [E5] The etching method according to any one of [E1] to [E4], wherein the first region includes a metal hard mask.

[0102] [E6] The etching method according to any one of [E1] to [E5], wherein the second region includes a dielectric film.

[0103] [E7] The etching method according to any one of [E1] to [E6], wherein the level of the electric bias supplied to the substrate support part that supports the substrate in (d) is higher than the level of the electric bias supplied to the substrate support part that supports the substrate in (b) or (c).

[0104] In this case, etching is promoted in (d).

[0105] [E8] The etching method according to any one of [E1] to [E7], wherein the first process gas contains fluorine and carbon.

[0106] [E9] The etching method according to any one of [E1] to [E8], wherein the second process gas is the same as the first process gas.

[0107] [E10] The etching method according to [E2] or any one of [E3] to [E9] citing [E2], wherein the cycle further includes, before (b), (f) generating a fourth plasma from a fourth process gas, and a power level of a source high frequency power used to generate the fourth plasma is higher than a power level of the source high frequency power used to generate the first plasma.

[0108] [E11] The etching method according to any one of [E1] to [E10], wherein (c) is performed after (b).

[0109] [E12] The etching method according to [E11], wherein (b) is carried out while the electron beam irradiation is stopped.

[0110] [E13] The etching method according to any one of [E1] to [E12], wherein (c) is carried out simultaneously with (b).

[0111] [E14] The etching method according to any one of [E1] to [E13], wherein (c) is carried out simultaneously with (b) and after (b).

[0112] a gas supply unit configured to supply a first process gas and a second process gas into the chamber; a plasma generation unit configured to generate a first plasma and a second plasma from the first process gas and the second process gas in the chamber, respectively; an electron beam irradiation source for irradiating an electron beam into the chamber; and a control unit, wherein the control unit is configured to control the gas supply unit, the plasma generation unit, and the electron beam irradiation source to perform an etching method including: (b) forming a deposit on the first region by the first plasma; (c) simultaneously with or after (b), irradiating the deposit with the electron beam to modify the deposit; and (d) after (c), etching the second region by the second plasma while the irradiation of the electron beam is stopped.

[0113] [E16] An etching method comprising: (a) providing a substrate, the substrate including a first region and a second region; (b) forming a deposit on the first region by a first plasma generated from a first process gas; (c) simultaneously with or after (b), irradiating the deposit with an electron beam to modify the deposit; and (d) after (c), etching the second region by a second plasma generated from a second process gas.

[0114] [E17] A plasma processing apparatus comprising: a chamber; a substrate support for supporting a substrate in the chamber, the substrate including a first region and a second region; a gas supply unit configured to supply a first process gas and a second process gas into the chamber; a plasma generation unit configured to generate a first plasma and a second plasma from the first process gas and the second process gas in the chamber, respectively; an electron beam irradiation source for irradiating an electron beam into the chamber; and a control unit, wherein the control unit is configured to control the gas supply unit, the plasma generation unit, and the electron beam irradiation source to perform an etching method including: (b) forming a deposit on the first region by the first plasma; (c) simultaneously with or after (b), irradiating the deposit with the electron beam to modify the deposit; and (d) after (c), etching the second region by the second plasma.

[0115] From the foregoing, it will be understood that various embodiments of the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope and spirit of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, with the true scope and spirit being indicated by the appended claims.

[0116] 1...plasma processing apparatus, 2...control unit, 10...plasma processing chamber, 11...substrate support unit, 12...plasma generation unit, 20...gas supply unit, DP, MDP...deposit, EB...electron beam, ES...electron beam irradiation source, PL1...first plasma, PL2...second plasma, R1...first region, R2...second region, W...substrate.

Claims

1. An etching method comprising: (a) providing a substrate, the substrate including a first region and a second region; (b) forming a deposit on the first region by a first plasma generated from a first process gas; (c) simultaneously with or after (b), irradiating the deposit with an electron beam to modify the deposit; and (d) after (c), etching the second region by a second plasma generated from a second process gas while the irradiation of the electron beam is stopped.

2. The etching method of claim 1, further comprising the step of: (e) repeating a cycle comprising (b), (c) and (d).

3. The etching method according to claim 1 or 2, wherein the deposit contains at least one of carbon and fluorine.

4. The etching method according to claim 1 or 2, wherein in (c), a third plasma is generated from a third processing gas, and the electron beam is generated by applying a negative voltage to an upper electrode provided above the substrate.

5. The etching method of claim 1 or 2, wherein the first region includes a metal hard mask.

6. The etching method according to claim 1 or 2, wherein the second region includes a dielectric film.

7. An etching method according to claim 1 or 2, wherein the level of the electrical bias supplied to the substrate support that supports the substrate in (d) is higher than the level of the electrical bias supplied to the substrate support that supports the substrate in (b) or (c).

8. The etching method according to claim 1 or 2, wherein the first process gas contains fluorine and carbon.

9. The etching method of claim 1 or 2, wherein the second process gas is the same as the first process gas.

10. The etching method of claim 2, wherein the cycle further comprises: (f) generating a fourth plasma from a fourth process gas before (b), and a power level of source radio frequency power used to generate the fourth plasma is higher than a power level of the source radio frequency power used to generate the first plasma.

11. The etching method according to claim 1 or 2, wherein (c) is carried out after (b).

12. The etching method according to claim 11, wherein (b) is carried out while the irradiation of the electron beam is stopped.

13. The etching method according to claim 1 or 2, wherein (c) is carried out simultaneously with (b).

14. The etching method according to claim 1 or 2, wherein (c) is carried out simultaneously with (b) and after (b).

15. A plasma processing apparatus comprising: a chamber; a substrate support for supporting a substrate in the chamber, the substrate including a first region and a second region; a gas supply unit configured to supply a first process gas and a second process gas into the chamber; a plasma generation unit configured to generate a first plasma and a second plasma from the first process gas and the second process gas, respectively, in the chamber; an electron beam irradiation source for irradiating an electron beam into the chamber; and a control unit, wherein the control unit is configured to control the gas supply unit, the plasma generation unit, and the electron beam irradiation source to perform an etching method including: (b) forming a deposit on the first region by the first plasma; (c) simultaneously with or after (b), irradiating the deposit with the electron beam to modify the deposit; and (d) after (c), etching the second region by the second plasma while the irradiation of the electron beam is stopped.

16. An etching method comprising: (a) providing a substrate, the substrate including a first region and a second region; (b) forming a deposit on the first region by a first plasma generated from a first processing gas; (c) simultaneously with or after (b), irradiating the deposit with an electron beam to modify the deposit; and (d) after (c), etching the second region by a second plasma generated from a second processing gas.

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