Etching method and plasma processing apparatus

Abstract

The disclosed etching method comprises: a step (a) in which a substrate is prepared in a chamber; (b) forming a deposit on the substrate; (c) modifying the deposit by supplying ions to the deposit from a plasma generated from the processing gas; and a step (d) in which, after the step (c), the dielectric film is etched using plasma. The substrate includes a dielectric film and a mask. The deposit is supplied from a plasma generated from a processing gas containing a gas component containing fluorine and carbon. The power level of the source high-frequency power in step (c) is equal to or less than the power level of the source high-frequency power in step (b). The level of the electrical bias in step (c) is higher than the level of the electrical bias in step (b), or the electrical bias is not supplied in step (b). The level of the electrical bias in step (d) is higher than the level of the electrical bias in step (c).

Description

Technical Field

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

[0002] A plasma processing device is used when plasma etching is performed on a film of a substrate. The plasma processing device includes a chamber and a substrate support. The substrate support is arranged in the chamber. When plasma etching is performed, source high-frequency power is supplied to generate plasma. Furthermore, bias high-frequency power is supplied to the substrate support to introduce ions into the substrate. The following patent document 1 discloses the content of controlling the phase difference between the pulse wave of the source high-frequency power and the pulse wave of the bias high-frequency power in plasma etching.

[0003] Previous technical literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-157735 Summary of the invention

[0006] Technical issues to be solved by the invention

[0007] The present invention provides a technology for suppressing the reduction of a metal hard mask due to etching.

[0008] Means for solving technical problems

[0009] In an exemplary embodiment, an etching method is provided. The etching method includes: step (a), preparing a substrate on a substrate support portion in a chamber of a plasma processing device. The substrate includes a dielectric film containing silicon and oxygen and a metal hard mask disposed on the dielectric film. The etching method also includes: step (b), forming a deposit on the substrate. The deposit is supplied from a plasma generated by a processing gas in the chamber, and the processing gas contains a gas component containing fluorine and carbon. The etching method also includes: step (c), modifying the deposit by supplying ions from the plasma generated by the processing gas to the deposit. The etching method also includes: step (d), after step (c), etching the dielectric film using the plasma generated in the chamber. The power level of the source high-frequency power used to generate plasma from the processing gas in step (c) is lower than the power level of the source high-frequency power used to generate plasma from the processing gas in step (b). The level of the electric bias supplied to the substrate support portion in step (c) is higher than the level of the electric bias supplied to the substrate support portion in step (b), or the electric bias is not supplied to the substrate support portion in step (b). The level of the electric bias supplied to the substrate support portion in step (d) is higher than the level of the electric bias supplied to the substrate support portion in step (c).

[0010] Effects of the Invention

[0011] According to an exemplary embodiment, a technique of suppressing reduction of a metal hard mask due to etching is provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a flow chart of an etching method according to an exemplary embodiment.

[0013] Figure 2 It is a diagram for explaining a configuration example of a plasma processing system.

[0014] Figure 3 It is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus.

[0015] Figure 4 (a) Figure 4 (b) Figure 4 (c) and Figure 4 (d) are partial enlarged cross-sectional views of an example of a substrate related to each step of the etching method according to an exemplary embodiment.

[0016] Figure 5 is a timing diagram related to an etching method according to an exemplary embodiment.

[0017] Figure 6 is a flow chart of an etching method according to another exemplary embodiment.

[0018] Figure 7 (a) Figure 7 (b) Figure 7 (c) and Figure 7 (d) are partial enlarged cross-sectional views of a substrate in one example related to each step of an etching method according to another exemplary embodiment.

[0019] Figure 8 It is a figure which shows the results of an evaluation experiment and a comparative experiment.

[0020] Fig. 9 is a flow chart of an etching method according to yet another exemplary embodiment.

[0021] Fig.10 is a timing chart related to an etching method according to still another exemplary embodiment.

[0022] Fig.11 (a) Fig.11 (b) and Fig.11 (c) are partial enlarged cross-sectional views of a substrate in one example related to each step of the etching method according to still another exemplary embodiment.

[0023] Fig.12 (a) Fig.12 (b) Fig.12 (c) and Fig.12 (d) is a diagram showing a deposit grown in an etching method according to still another exemplary embodiment. DETAILED DESCRIPTION

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

[0025] Figure 1 is a flow chart of an etching method according to an exemplary embodiment. Figure 1 The etching method shown (hereinafter referred to as "method MT") is performed to etch a dielectric film on a substrate in a plasma processing apparatus.

[0026] Figure 2 : is a diagram for illustrating a structural example of a plasma processing system. In one embodiment, the plasma processing system includes a plasma processing device 1 and a control unit 2. The plasma processing system is an example of a substrate processing system, and the plasma processing device 1 is an example of a substrate processing device. The plasma processing device 1 includes a plasma processing chamber 10, a substrate support portion 11, and a plasma generating portion 12. The plasma processing chamber 10 has a plasma processing space. In addition, the plasma processing chamber 10 has: at least one gas supply port for supplying at least one processing gas to the plasma processing space; and at least one gas exhaust port for exhausting gas from the plasma processing space. The gas supply port is connected to the gas supply portion 20 described later, and the gas exhaust port is connected to the exhaust system 40 described later. The substrate support portion 11 is arranged in the plasma processing space and has a substrate supporting surface for supporting a substrate.

[0027] The plasma generating unit 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma formed in the plasma processing space may also be capacitively coupled plasma (CCP: Capacitively Coupled Plasma), inductively coupled plasma (ICP: Inductively Coupled Plasma), ECR plasma (Electron-Cyclotron-Resonance Plasma, electron cyclotron resonance plasma), helicon wave plasma (HWP: Helicon Wave Plasma), or surface wave plasma (SWP: Surface Wave Plasma).

[0028] The control unit 2 processes computer executable instructions that cause the plasma processing device 1 to perform various processes described in the present invention. The control unit 2 can be configured to control the various elements of the plasma processing device 1 in a manner that performs various processes described herein. In one embodiment, a portion or all of the control unit 2 can be included in the plasma processing device 1. The control unit 2 can include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The control unit 2 is implemented, for example, by a computer 2a. The processing unit 2a1 can be configured to read a program from the storage unit 2a2 and execute the read program, thereby performing various control operations. The program can be pre-stored in the storage unit 2a2, or it can be obtained via a medium when necessary. The obtained program is stored in the storage unit 2a2, and is read and executed from the storage unit 2a2 by the processing unit 2a1. The medium can be various storage media that can be read to the computer 2a, or it can be a communication line connected to the communication interface 2a3. The processing unit 2a1 can also be a CPU (Central Processing Unit). The storage unit 2a2 may also include a RAM (Random Access Memory), a ROM (Read Only Memory), a HDD (Hard Disk Drive), an SSD (Solid State Drive), or a combination thereof. The communication interface 2a3 may also communicate with the plasma processing device 1 via a communication line such as a LAN (Local Area Network).

[0029] Hereinafter, a configuration example of a capacitively coupled plasma processing apparatus as an example of the plasma processing apparatus 1 will be described. Figure 3 It is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus.

[0030] The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply system 30, and an exhaust system 40. Furthermore, the plasma processing apparatus 1 includes a substrate support unit 11 and a gas introduction unit. The gas introduction unit is configured to introduce at least one processing gas into the plasma processing chamber 10. The gas introduction unit includes a shower head 13. The substrate support unit 11 is disposed in the plasma processing chamber 10. The shower head 13 is disposed above the substrate support unit 11. In one embodiment, the shower head 13 constitutes at least a portion of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the shower head 13, a side wall 10a of the plasma processing chamber 10, and the substrate support unit 11. The plasma processing chamber 10 is grounded. The substrate support unit 11 is electrically insulated from the frame of the plasma processing chamber 10.

[0031] The substrate support portion 11 includes a main body 111 and a ring assembly 112. The main body 111 has a central area 111a for supporting a substrate W, and an annular area 111b for supporting the ring assembly 112. A wafer is an example of a substrate W. When viewed from above, the annular area 111b of the main body 111 surrounds the central area 111a of the main body 111. The substrate W is arranged on the central area 111a of the main body 111, and the ring assembly 112 is arranged on the annular area 111b of the main body 111 in a manner that surrounds the substrate W on the central area 111a of the main body 111. Therefore, the central area 111a is also referred to as a substrate supporting surface for supporting the substrate W, and the annular area 111b is also referred to as a ring supporting surface for supporting the ring assembly 112.

[0032] In one embodiment, the main body 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive component. The electrostatic chuck 1111 is disposed on the base 1110. The electrostatic chuck 1111 includes a ceramic component 1111a and an electrostatic electrode 1111b disposed in the ceramic component 1111a. The ceramic component 1111a has a central area 111a. In one embodiment, the ceramic component 1111a also has an annular area 111b. In addition, other components surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating component, may also have an annular area 111b. In this case, the ring assembly 112 may be disposed on the annular electrostatic chuck or the annular insulating component, or on both the electrostatic chuck 1111 and the annular insulating component.

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

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

[0035] The shower head 13 is configured to introduce at least one processing gas from the gas supply part 20 into the plasma processing space 10s. The shower head 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b and a plurality of gas introduction ports 13c. The processing gas supplied to the gas supply port 13a is introduced into the plasma processing space 10s from the plurality of gas introduction ports 13c through the gas diffusion chamber 13b. In addition, the shower head 13 includes at least one upper electrode. In addition, in addition to the shower head 13, the gas introduction part may also include one or more side gas injection parts (SGI: Side Gas Injector) installed in one or more openings formed in the side wall 10a.

[0036] The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one process gas from each corresponding gas source 21 to the shower head 13 via each corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. In addition, the gas supply unit 20 may include at least one flow modulation device for modulating or pulsing the flow of at least one process gas.

[0037] The exhaust system 40 can be connected to the gas outlet 10e provided at the bottom of the plasma processing chamber 10, for example. The exhaust system 40 can 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 can include a turbomolecular pump, a dry pump, or a combination thereof.

[0038] The power supply system 30 includes a high frequency power supply 31 and a bias power supply 32. The high frequency power supply 31 constitutes the plasma generating unit 12 of one embodiment. The high frequency power supply 31 is configured to generate a source high frequency power RF. The source high frequency power RF has a source frequency f RF That is, the source high frequency power RF has a frequency of source frequency f RF The source frequency is f RFThe frequency may be in the range of 13 MHz to 100 MHz. The high frequency power supply 31 is configured to be electrically connected to the high frequency electrode via the matching device 33, and to supply the source high frequency power RF to the high frequency electrode. The high frequency electrode may be disposed in the substrate support portion 11. The high frequency electrode may also be at least one electrode disposed in a conductive component of the susceptor 1110 or in a ceramic component 1111a. Alternatively, the high frequency electrode may be an upper electrode. If the source high frequency power RF is supplied to the high frequency electrode, plasma is generated from the gas in the chamber 10.

[0039] The matching device 33 has a variable impedance. The variable impedance of the matching device 33 is set to reduce the reflection of the source high frequency power RF at the load. The matching device 33 can be controlled by the control unit 2, for example.

[0040] The bias power supply 32 is electrically coupled to the substrate support 11. The bias power supply 32 is configured to be electrically connected to the bias electrode in the substrate support 11 and to supply the electric bias EB to the bias electrode. The bias electrode may also be at least one electrode provided in a conductive component of the base 1110 or in the ceramic component 1111a. The bias electrode may be the same as the high-frequency electrode. When the electric bias EB is supplied to the bias electrode, ions from the plasma are attracted to the substrate W.

[0041] The electrical bias EB has a waveform period and is periodically supplied to the bias electrode from the bias power supply 32. The waveform period of the electrical bias EB is determined by the bias frequency. The bias frequency is, for example, a frequency of 100 kHz or more and 50 MHz or less. The time length of the waveform period of the electrical bias EB is the inverse of the bias frequency.

[0042] The electrical bias EB may be a bias high frequency power having a bias frequency. That is, the electrical bias EB may have a sinusoidal waveform whose frequency is the bias frequency. In this case, the bias power supply 32 is electrically connected to the bias electrode via the matching device 34. The variable impedance of the matching device 34 is set to reduce the reflection of the load from the bias high frequency power.

[0043] Alternatively, the electrical bias EB may include a voltage pulse. The voltage pulse is applied to the bias electrode within the waveform period. The voltage pulse is periodically applied to the bias electrode at a time interval of the same length as the time length of the waveform period. The waveform of the voltage pulse may be a rectangular wave, a triangular wave, or an arbitrary waveform. The polarity of the voltage of the voltage pulse is set to be able to generate a potential difference between the substrate W and the plasma to introduce ions from the plasma into the substrate W. The voltage pulse may also be a pulse of a negative voltage or a pulse of a negative DC voltage. In the case where the electrical bias EB includes a voltage pulse, the plasma processing device 1 may not have a matcher 34.

[0044] In addition, the level of the electric bias EB is sometimes described below. When the electric bias EB is bias high frequency power, the level of the electric bias EB is the power level of the bias high frequency power. When the electric bias EB includes a voltage pulse, the level of the electric bias EB is the absolute value of the negative voltage level of the voltage pulse.

[0045] The power supply system 30 may further include a trigger signal generator 30c. The trigger signal generator 30c applies a trigger signal to the high frequency power supply 31 and the bias power supply 32, respectively. The output timing of the trigger signals applied to the high frequency power supply 31 and the bias power supply 32, respectively, can be specified by the control unit 2. The high frequency power supply 31 generates the source high frequency power RF or changes its power level at the timing corresponding to the given trigger signal. And, the bias power supply 32 generates the electric bias voltage EB or changes its level at the timing corresponding to the given trigger signal.

[0046] The power supply system 30 may further include a power supply 35. The power supply 35 is electrically connected to the upper electrode. In one embodiment, the upper electrode includes a top plate 13p. The top plate 13p divides the internal space of the chamber 10 from above. That is, the top plate 13p is in contact with the internal space of the chamber 10. The top plate 13p may be formed of silicon. The power supply 35 is configured to apply a negative voltage NV (e.g., a negative DC voltage) to the upper electrode. The power supply 35 outputs a negative voltage NV to the upper electrode or changes the absolute value of its voltage level at a timing corresponding to a trigger signal given from the trigger signal generator 30c. The output timing of the trigger signal given to the power supply 35 can be specified by the control unit 2.

[0047] Below, reference Figure 1 and Figure 4 (a)~ Figure 4 (d) and Figure 5 , the method MT will be described. Furthermore, the control of each part of the plasma processing apparatus 1 by the control unit 2 will also be described. Figure 4 (a)~ Figure 4 (d) are partial enlarged cross-sectional views of an example of a substrate related to each step of the etching method according to an exemplary embodiment. Figure 5 1 is a timing chart related to an etching method according to an exemplary embodiment. Hereinafter, the method MT will be described by taking the case of using the plasma processing apparatus 1 as an example. In addition, the method MT may be performed using a plasma processing apparatus different from the plasma processing apparatus 1.

[0048] like Figure 1 As shown, the method MT includes steps STa, STc, STe, and STf. The method MT may further include at least one of steps STb, STd, and STg.

[0049] In step STa, a substrate W is prepared on the substrate support 11 in the chamber 10 of the plasma processing apparatus 1 . The steps of method MT performed after step STa are performed with the substrate W placed on the substrate support 11 .

[0050] like Figure 4 As shown in (a), the substrate W includes a film EF and a mask MHM. The substrate W may further include a base region UR. The film EF is a film etched in the method MT. The film EF is disposed on the base region UR. The film EF may be a dielectric film containing silicon and oxygen. The mask MHM is a metal hard mask disposed on the film EF. The mask MHM has a pattern transferred to the film EF by etching. That is, the mask MHM provides more than one opening. The mask MHM may include at least one metal selected from the group consisting of titanium, tungsten, molybdenum and ruthenium. The mask MHM is formed, for example, of titanium nitride. The mask MHM may be formed of other metal-containing materials.

[0051] Step STb is performed after step STa and before step STc. Step STb is performed during period P1 (refer to Figure 5 ) is performed. In step STb, plasma is generated in chamber 10 by a processing gas. The processing gas is a gas having deposition properties. The processing gas includes a gas component containing fluorine and carbon. The gas component may be, for example, C 4 F 8 The gas component may also include a hydrofluorocarbon gas in addition to the fluorocarbon gas, or may include a hydrofluorocarbon gas instead of the fluorocarbon gas. The processing gas may further include one or more of nitrogen, an oxygen-containing gas (e.g., oxygen) and a rare gas (e.g., Ar gas). In step STb, plasma is ignited in the chamber 10 to generate free radicals from the gas component of the processing gas.

[0052] In step STb, the control unit 2 controls the gas supply unit 20 so as to supply the processing gas into the chamber 10. In step STb, the control unit 2 controls the exhaust system 40 so as to set the pressure in the chamber 10 to a specified pressure. In step STb, the control unit 2 controls the high-frequency power supply 31 so as to supply the source high-frequency power RF to the high-frequency electrode so as to generate plasma from the processing gas. In one embodiment, the power level of the source high-frequency power RF used in step STb may be higher than the power level of the source high-frequency power RF used in the later steps STc and STe. In step STb, the control unit 2 may control the bias power supply 32 so as not to supply the electrical bias EB to the bias electrode. Alternatively, in step STb, the control unit 2 may control the bias power supply 32 so as to supply the electrical bias EB to the bias electrode.

[0053] Next, in method MT, step STc is performed. In one embodiment, step STc is performed after step STb. In one embodiment, step STc is performed during period P2 (refer to Figure 5 The period P2 is a period after the period P1 or immediately following the period P1.

[0054] In step STc, a deposit DP is formed on the substrate W (see Figure 4 (b)) The deposit DP is supplied from the plasma generated from the above-mentioned process gas in the chamber 10. That is, the process gas used in step STb may be the same as the process gas used in step STc. The deposit DP contains carbon and fluorine.

[0055] In step STc, the control unit 2 controls the gas supply unit 20 so as to supply the processing gas into the chamber 10. In step STc, the control unit 2 controls the exhaust system 40 so as to set the pressure in the chamber 10 to a specified pressure. In step STc, the control unit 2 controls the high-frequency power supply 31 so as to supply the source high-frequency power RF to the high-frequency electrode to generate plasma from the processing gas. In one embodiment, the power level of the source high-frequency power RF used in step STc may be lower than the power level of the source high-frequency power RF used in step STb. In step STc, the control unit 2 may control the bias power supply 32 so as not to supply the electrical bias EB to the bias electrode. Alternatively, in step STc, the control unit 2 may control the bias power supply 32 so as to supply the electrical bias EB to the bias electrode.

[0056] The step STd is performed at least in parallel with the step STc. That is, the step STd is performed at least in the period P2. The step STd may be performed in the period P1 in addition to the period P2.

[0057] In step STd, a negative voltage NV is applied to the upper electrode. In step STd, positive ions are attracted to the top plate 13p from the plasma in the chamber 10. As a result, the substance (for example, silicon) constituting the top plate 13p is released. The substance released from the top plate 13p is bonded to the fluorine chemical species in the plasma, thereby reducing the amount of the fluorine chemical species in the plasma.

[0058] In step STd, the control unit 2 controls the power supply 35 so that the negative voltage NV is applied to the upper electrode. In addition, the negative voltage NV may be applied to the upper electrode during at least one of the periods P3 and P4 described later. The absolute value of the negative voltage NV applied to the upper electrode during the periods P1 and P2 may be set to a value greater than the absolute value of the negative voltage NV applied to the upper electrode during the periods P3 and P4.

[0059] Step STe is performed after step STc. Step STe is performed during period P3 (refer to Figure 5 The period P3 is a period after the period P2 or immediately following the period P2.

[0060] In step STe, ions are supplied to the deposit DP from the plasma generated from the above-mentioned processing gas, so that the deposit DP is modified. Figure 4 As shown in (c), the deposit MDP is generated from the deposit DP. The process gas used in step STe may be the same process gas as the process gas used in step STc. In step STe, the energy of ions supplied from plasma to the deposit DP is higher than the energy of ions supplied from plasma to the substrate W in step STc. In step STe, ions with relatively high energy are supplied to the deposit DP, and elements other than carbon are taken out from the deposit DP. Therefore, in the deposit MDP obtained in step STe, many carbon-to-carbon bonds with high bond energy can be formed.

[0061] In step STe, the control unit 2 controls the gas supply unit 20 so as to supply the processing gas into the chamber 10. In step STe, the control unit 2 controls the exhaust system 40 so as to set the pressure in the chamber 10 to a specified pressure. In step STe, the control unit 2 controls the high-frequency power supply 31 so as to supply the source high-frequency power RF to the high-frequency electrode to generate plasma from the processing gas. In one embodiment, the power level of the source high-frequency power RF used in step STe may be lower than the power level of the source high-frequency power RF used in step STb. In one embodiment, the power level of the source high-frequency power RF used in step STe may be lower than the power level of the source high-frequency power RF used in step STc. In step STe, the control unit 2 controls the bias power supply 32 so as to supply the electric bias EB to the bias electrode. In one embodiment, the level of the electric bias EB used in step STe may be higher than the level of the electric bias EB used in step STc. In one embodiment, the level of the electric bias EB used in step STe may be higher than the level of the electric bias EB used in step STb. In addition, as described above, in at least one of step STb and step STc, the supply of the electric bias EB may be stopped.

[0062] Step STf is performed after step STe. Step STf is performed during period P4 (refer to Figure 5 The period P4 is a period after the period P3 or immediately following the period P3.

[0063] In step STf, the film EF is etched using the plasma generated in the chamber 10 (see Figure 4(d)). In step STf, plasma can be generated from the above-mentioned processing gas. That is, in step STf, the same processing gas as that used in step STc and step STe can be used. Alternatively, the processing gas used in step STf can be another gas selected in a manner to selectively etch the film EF.

[0064] In step STf, the control unit 2 controls the gas supply unit 20 so as to supply the processing gas into the chamber 10. In step STf, the control unit 2 controls the exhaust system 40 so as to set the pressure in the chamber 10 to a specified pressure. In step STf, the control unit 2 controls the high-frequency power supply 31 so as to supply the source high-frequency power RF to the high-frequency electrode to generate plasma from the processing gas. In one embodiment, the power level of the source high-frequency power RF used in step STf may be lower than the power level of the source high-frequency power RF used in step STb. In one embodiment, the power level of the source high-frequency power RF used in step STf may be lower than the power level of the source high-frequency power RF used in step STc. In step STf, the control unit 2 controls the bias power supply 32 so as to supply the electric bias EB to the bias electrode. In one embodiment, the level of the electric bias EB used in step STf may be higher than the level of the electric bias EB used in step STe.

[0065] In the method MT, the mask MHM is protected from the etching in the step STf by the deposit MDP. Therefore, according to the method MT, the reduction of the mask MHM due to etching is suppressed.

[0066] The method MT may end after the etching of step STf. In one embodiment, the cycle CY including the steps STc, STe, and STf may be repeated. The cycle CY may further include at least one of the steps STb and STd.

[0067] Cycle CY may further include step STg. Step STg is performed after step STf. Step STg is performed during period P5 (refer to Figure 5 The period P5 is a period after the period P4 or immediately following the period P4.

[0068] In step STg, the reaction product generated in step STf is exhausted from the chamber 10. In step STg, plasma may not be generated in the chamber 10.

[0069] In step STg, the control unit 2 controls the exhaust system 40 to exhaust the chamber 10 and discharge the reaction product from the chamber 10. In step STg, the control unit 2 may control the high frequency power source 31 to stop supplying the source high frequency power RF. In step STg, the control unit 2 may control the bias power source 32 to stop supplying the electric bias EB.

[0070] In the case where the loop CY is repeated, the method MT further includes a step STJ. In the step STJ, it is determined whether the stop condition is satisfied. The stop condition is satisfied when the number of executions of the loop CY reaches a predetermined number. In the step STJ, if it is determined that the stop condition is not satisfied, the loop CY is performed again. In the step STJ, if it is determined that the stop condition is satisfied, the method MT ends.

[0071] Here, the energy of ions supplied to the substrate W in the period P1 (step STb), the period P2 (step STc), the period P3 (step STe), and the period P4 (step STf) is represented by E. 1 、E 2 、E 3 、E 4 The power level of the source high frequency power RF in each of the period P1, the period P2, the period P3, and the period P4 is represented by L RF1 , L RF2 , L RF3 , L RF4 Furthermore, the level of the electric bias EB in each of the period P1, the period P2, the period P3, and the period P4 is represented by L EB1 , L EB2 , L EB3 , L EB4 The power level of the source high frequency power RF and the voltage of the electric bias EB in each step of the method MT only need to satisfy 0 <E 1 and E 2 <E 3 <E 4 , is not limited to the above examples.

[0072] For example, the power level of the source high frequency power RF may satisfy any one of the following (A1) to (A4), and the level of the electric bias EB may satisfy any one of the following (A5) to (A10).

[0073] (A1)0≤L RF4 <L RF2 <L RF3 <L RF1

[0074] (A2)0 <L RF2 ≤L RF4 <L RF3 <LRF1

[0075] (A3)0 <L RF2 <L RF3 ≤L RF4 <L RF1

[0076] (A4)0 <L RF2 <L RF3 <L RF1 ≤L RF4

[0077] (A5)0≤L EB1 ≤L EB2 ≤L EB3 <L EB4

[0078] (A6)0≤L EB2 ≤L EB1 ≤L EB3 <L EB4

[0079] (A7)0≤L EB3 ≤L EB1 ≤L EB2 <L EB4

[0080] (A8)0≤L EB3 ≤L EB2 ≤L EB1 <L EB4

[0081] (A9)0≤L EB1 ≤L EB3 ≤L EB2 <L EB4

[0082] (A10)0≤L EB2 ≤L EB3 ≤L EB1 <L EB4

[0083] Alternatively, the power level of the source high-frequency power RF may satisfy any one of the following (B1) to (B4), and the voltage of the electric bias EB may satisfy any one of the following (B5) to (B10).

[0084] (B1)0≤L RF4 <L RF2 <L RF1 <L RF3

[0085] (B2)0 <L RF2 ≤L RF4 <L RF1 <LRF3

[0086] (B3)0 <L RF2 <L RF1 ≤L RF4 <L RF3

[0087] (B4)0 <L RF2 <L RF1 <L RF3 ≤L RF4

[0088] (B5)0≤L EB1 ≤L EB2 ≤L EB3 <L EB4

[0089] (B6)0≤L EB2 ≤L EB1 ≤L EB3 <L EB4

[0090] (B7)0≤L EB3 ≤L EB1 ≤L EB2 <L EB4

[0091] (B8)0≤L EB3 ≤L EB2 ≤L EB1 <L EB4

[0092] (B9)0≤L EB1 ≤L EB3 ≤L EB2 <L EB4

[0093] (B10)0≤L EB2 ≤L EB3 ≤L EB1 <L EB4

[0094] Alternatively, the power level of the source high-frequency power RF may satisfy any one of the following (C1) to (C4), and the voltage of the electric bias EB may satisfy any one of the following (C5) to (C7).

[0095] (C1)0≤L RF4 <L RF3 ≤L RF2 <L RF1

[0096] (C2)0 <L RF3 ≤L RF4 ≤L RF2 <LRF1

[0097] (C3)0 <L RF3 ≤L RF2 ≤L RF4 <L RF1

[0098] (C4)0 <L RF3 ≤L RF2 <L RF1 ≤L RF4

[0099] (C5)0≤L EB1 <L EB3 <L EB3 <L EB4

[0100] (C6)0 <L EB3 ≤L EB1 <L EB3 <L EB4

[0101] (C7)0 <L EB3 <L EB3 ≤L EB1 <L EB4

[0102] Below, reference Figure 6 and Figure 7 (a)~ Figure 7 (d) An etching method according to another exemplary embodiment will be described. Figure 6 is a flow chart of an etching method according to another exemplary embodiment.

[0103] Figure 7 (a)~ Figure 7 (d) are partial enlarged cross-sectional views of a substrate in accordance with an example of each step of an etching method according to another exemplary embodiment. Figure 6 The etching method shown in FIG. 1 (hereinafter referred to as “method MTA”) will be described. In addition, method MTA may be performed using a plasma processing apparatus different from plasma processing apparatus 1 .

[0104] Method MTA applies to Figure 7 (a) shows a substrate W. Figure 7 As shown in (a), the substrate W includes a base region UR, a film EF, a mask MHM, a silicon oxide film OXM, an organic film OF, a silicon-containing film ARF, and a resist mask PR.

[0105] The substrate region UR is, for example, an etching stop layer. The substrate region UR may have a stacked structure including an aluminum oxide film and a SiCN film. The film EF is disposed on the substrate 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 dielectric constant film LKF. The film EF may have a stacked structure including a low dielectric constant film LKF and a silicon oxide film OXF. In addition, the low dielectric constant film LKF may be a SiOCH film.

[0106] The mask MHM is a metal hard mask and is disposed on the film EF. The mask MHM has a pattern transferred to the film EF by etching. That is, the mask MHM provides one or more openings. The mask MHM may include at least one metal selected from the group consisting of titanium, tungsten, molybdenum and ruthenium. The mask MHM is formed of titanium nitride, for example. The mask MHM may be formed of other metal-containing materials.

[0107] The silicon oxide film OXM is disposed on the top of the mask MHM. The organic film OF is disposed to cover the silicon oxide film OXM, the mask MHM and the film EF. The silicon-containing film ARF is disposed on the organic film OF. The silicon-containing film ARF may be an anti-reflection film. The resist mask PR is disposed on the silicon-containing film ARF. The resist mask PR is patterned using a photolithography technique. The resist mask PR provides one or more openings in order to form a recess (e.g., a groove or a hole) in the film EF at the portion exposed from the mask MHM.

[0108] Return to Figure 6 In step STa of method MTA, similarly to step STa of method MT, a substrate W is prepared on a substrate support 11 in a chamber 10 of a plasma processing apparatus 1 (see Figure 7 (a) The steps of the method MTA performed after the step STa are performed with the substrate W placed on the substrate supporting portion 11 .

[0109] In the method MTA, after the step STa, the step ST1 is performed. In the step ST1, the silicon-containing film ARF is etched. Through the step ST1, the pattern of the resist mask PR is transferred to the silicon-containing film ARF. In the step ST1, in order to etch the silicon-containing film ARF, plasma is generated by an etching gas in the chamber 10. The etching gas used in the step ST1 includes a fluorocarbon gas and a rare gas (for example, Ar gas).

[0110] In step ST1, the control unit 2 controls the gas supply unit 20 to supply the etching gas into the chamber 10. In step ST1, the control unit 2 controls the exhaust system 40 to set the pressure in the chamber 10 to a specified pressure. In step ST1, the control unit 2 controls the high-frequency power supply 31 to supply the source high-frequency power RF to the high-frequency electrode to generate plasma from the etching gas. In step ST1, the control unit 2 may control the bias power supply 32 to supply the electric bias EB to the bias electrode.

[0111] Next, step ST2 is performed. In step ST2, the organic film OF is etched. Figure 7 As shown in (b), the pattern of the silicon-containing film ARF is transferred to the organic film OF. In step ST2, in order to etch the organic film OF, plasma is generated by an etching gas in the chamber 10. The etching gas used in step ST2 contains an oxygen-containing gas (e.g., oxygen). Alternatively, the etching gas used in step ST2 may contain nitrogen and hydrogen.

[0112] In step ST2, the control unit 2 controls the gas supply unit 20 to supply the etching gas into the chamber 10. In step ST2, the control unit 2 controls the exhaust system 40 to set the pressure in the chamber 10 to a specified pressure. In step ST2, the control unit 2 controls the high-frequency power supply 31 to supply the source high-frequency power RF to the high-frequency electrode to generate plasma from the etching gas. In step ST2, the control unit 2 may control the bias power supply 32 to supply the electric bias EB to the bias electrode.

[0113] Next, step ST3 is performed. In step ST3, the film EF is etched. In step ST3, the above-mentioned steps STc, STe, and STf are performed. In step ST3, at least one of the above-mentioned steps STb, STd, and STg may be further performed. In step ST3, the above-mentioned cycle CY may be repeated. Through step ST3, as Figure 7 As shown in (c), the pattern of the organic film OF is transferred to the film EF, thereby forming a concave portion in the film EF.

[0114] Next, step ST4 is performed. In step ST4, the organic film OF is removed. In step ST4, in order to remove the organic film OF, plasma is generated from an ashing gas in the chamber 10. The ashing gas used in step ST4 contains an oxygen-containing gas (for example, oxygen gas and / or CO gas).

[0115] In step ST4, the control unit 2 controls the gas supply unit 20 to supply the ashing gas into the chamber 10. In step ST4, the control unit 2 controls the exhaust system 40 to set the pressure in the chamber 10 to a specified pressure. In step ST4, the control unit 2 controls the high-frequency power source 31 to supply the source high-frequency power RF to the high-frequency electrode to generate plasma from the etching gas.

[0116] Next, step ST5 is performed. In step ST5, Figure 7 As shown in (d), the film EF is further etched in such a manner as to increase the depth of the recess. In step ST5, the above-mentioned steps STc, STe, and STf are performed. In step ST5, at least one of the above-mentioned steps STb, STd, and STg may be further performed. In step ST5, the above-mentioned cycle CY may be repeated.

[0117] According to the method MTA, when the film EF is etched in the steps ST3 and ST5, the mask MHM is protected by the deposit MDP. Therefore, the reduction of the mask MHM caused by the etching of the film EF is suppressed. Furthermore, according to the method MTA, even if the pattern of the resist mask PR is offset relative to the pattern of the mask MHM, the film EF can be etched while suppressing the reduction of the mask MHM.

[0118] The following describes an evaluation experiment and the first to third comparative experiments conducted to evaluate the method MT. In the evaluation experiment and the first to third comparative experiments, a sample substrate having a titanium nitride film was prepared. In the evaluation experiment, the plasma processing device 1 was used to perform the steps STc and STe, and a deposit was formed on the titanium nitride film of the sample substrate. In the first and second comparative experiments, the plasma processing device 1 was used to perform only the step STc, and a deposit was formed on the titanium nitride film of the sample substrate. In the third comparative experiment, the plasma processing device 1 was used to perform only the step STe, and an attempt was made to form a deposit on the titanium nitride film of the sample substrate. The following shows the conditions of the evaluation experiment and the first to third comparative experiments.

[0119] (Evaluation Experiment, 2nd and 3rd Comparative Experiment)

[0120] Processing gas: nitrogen, C 4 F 8 Mixed gas of gas, oxygen, and Ar gas

[0121] Source high frequency power, bias high frequency power in step STc: 100W, 0W

[0122] Source high frequency power, bias high frequency power of process STe: 30W, 30W

[0123] (Comparative Experiment No. 1)

[0124] Processing gas: nitrogen, C 4 F 8 Mixed gas of gas, oxygen, and Ar gas

[0125] Source high frequency power, bias high frequency power in step STc: 30W, 0W

[0126] In the evaluation experiment and the first to third comparative experiments, the ratio of carbon interbonds in the deposit was measured by X-ray photoelectron spectroscopy (XPS). As a result, the ratio of carbon interbonds in the deposit measured in the first to second comparative experiments and the evaluation experiment was 17.02%, 19.73%, and 29.83%. In addition, in the third comparative experiment, almost no deposit was formed. Thus, it was confirmed that by performing the steps STc and STe, a deposit containing carbon interbonds can be formed on the substrate at a high ratio.

[0127] The following describes the first to third evaluation experiments and comparative experiments conducted to evaluate the MTA method. Figure 7 (a) A sample substrate having the structure shown. In the sample substrate, the mask MHM is formed of titanium nitride. Then, in the first to third evaluation experiments and the comparative experiment, steps ST1 to ST3 were applied to the sample substrate using the plasma processing apparatus 1. However, in the comparative experiment, step STe was not performed in step ST3. The conditions of each of the first to third evaluation experiments and the comparative experiment are shown below.

[0128] (1st to 3rd evaluation experiments and comparative experiments)

[0129] Processing gas: nitrogen, C 4 F 8 Mixed gas of gas, oxygen, and Ar gas

[0130] Source high frequency power, bias high frequency power in step STb: 1000W, 0W

[0131] Source high frequency power, bias high frequency power in step STc: 100W, 0W

[0132] Source high frequency power of each step STe in the first to third evaluation experiments: 30 W

[0133] Bias high frequency power in each step STe of the first to third evaluation experiments: 10 W, 30 W, 50 W

[0134] Source high frequency power and bias high frequency power of process STf: 30W and 900W

[0135] In the first to third evaluation experiments and the comparative experiment, the selectivity between the etching of the mask MHM and the etching of the film EF was determined. The selectivity is a value obtained by dividing the amount of reduction in the thickness of the mask MHM by the depth of the recessed portion formed in the film EF. Figure 8 The results of the first to third evaluation experiments and the comparative experiment are shown in FIG. Figure 8 The relationship between the energy of the ions supplied to the substrate W and the selectivity in each step STe of the first to third evaluation experiments is shown in FIG. In addition, the energy of the ions supplied to the substrate W in the steps STe of the first to third evaluation experiments is 120 eV, 160 eV, and 190 eV, respectively. Figure 8 FIG. 2 shows the relationship between the energy of ions supplied to the substrate W and the selectivity in step STc of the comparative experiment. Figure 8 As shown, in the first to third evaluation experiments, a significantly higher selectivity was obtained compared to the comparative experiment. Therefore, it was confirmed that when step ST3 includes step STc and step STe, a high selectivity can be obtained, that is, the reduction of mask MHM due to etching of film EF is suppressed.

[0136] Below, reference Fig. 9 , an etching method according to another exemplary embodiment is described. Fig. 9 is a flow chart of an etching method according to yet another exemplary embodiment. Fig. 9 The etching method shown (hereinafter referred to as “method MTB”) is performed in order to etch a dielectric film of a substrate in a plasma processing apparatus. The plasma processing apparatus used in the method MTB may be the plasma processing apparatus 1 .

[0137] Below, reference Fig. 9 and Fig.10 . Fig.10 2 is a timing chart related to a plasma processing apparatus according to an exemplary embodiment. The control unit 2 executes a first control of repeatedly performing a first cycle CYB1.

[0138] The first cycle CYB1 is performed in a state where a deposition-type processing gas is supplied into the chamber 10. The deposition-type processing gas will be described later. The control unit 2 controls the high-frequency power supply 31 and the bias power supply 32 in the first cycle CYB1 so as to sequentially change at least one of the power level of the source high-frequency power RF and the level of the electrical bias voltage to two different levels. Furthermore, the control unit 2 may control the power supply 35 in the first cycle CYB1 so as to sequentially change the level (absolute value of the voltage level) of the negative voltage NV applied to the upper electrode to two different levels.

[0139] In one embodiment, in the first cycle CYB1, the power level of the source high frequency power RF and the level of the electrical bias voltage may be sequentially changed to two different levels. For example, in the first cycle CYB1, the power level of the source high frequency power RF may be sequentially changed to power level LB RF1 and power level LB RF2 , the level of the electrical bias EB can be changed to level LB EB1 and horizontal LB EB2 In addition, LB RF1 Greater than LB RF2 , L.B. EB2 Greater than LB EB1 Furthermore, in the first cycle CYB1, the level of the negative voltage NV (the absolute value of the voltage level) can be sequentially changed to the level LB NV1 and horizontal LB NV2 In addition, horizontal LB NV1 Greater than horizontal LB NV2 .

[0140] The power level of the source radio frequency power RF and the level of the electrical bias voltage in the first cycle CYB1 may be changed synchronously with each other. For example, the power level of the source radio frequency power RF is the power level LB RF1 The period and level of the electrical bias EB is level LB EB1 The periods can be synchronized with each other. And, the power level of the source high frequency power RF is the power level LB RF2 The period and level of the electrical bias EB is level LB EB2 The periods can be synchronized with each other.

[0141] Furthermore, the change in the level of the negative voltage NV in the first cycle CYB1 may be synchronized with the change in the power level of the source radio frequency power RF. For example, the power level of the source radio frequency power RF is the power level LB RF1 The negative voltage NV is at level LB during NV1 For example, the power level of the source high frequency power RF is the power level LB RF2 The negative voltage NV is at level LB during NV2 The periods can be synchronized with each other.

[0142] The repetition frequency of the first cycle CYB1 can be 1 Hz or more and 50 kHz or less. The repetition frequency of the first cycle CYB1 can be 100 Hz or more and 21 kHz or less. Furthermore, the power level of the source high-frequency power RF can be a power level in the range of 0 W or 7 W or more and 3000 W or less. Furthermore, when the electric bias EB is the bias high-frequency power, the power level of the bias high-frequency power can be a power level in the range of 0 W or 7 W or more and 3000 W or less.

[0143] Furthermore, the control unit 2 performs the second control after the first control, that is, after the repetition of the first cycle. In the second control, the control unit 2 controls the high-frequency power supply 31 and the bias power supply 32 to supply the source high-frequency power RF and the electrical bias EB to generate the plasma of the etching gas in the chamber 10. In the second control, the power level of the source high-frequency power RF can be set to a power level within the range of 7W or more and 3000W or less. Moreover, in the case where the electrical bias EB is the bias high-frequency power, in the second control, the power level of the bias high-frequency power can be set to a power level within the range of 7W or more and 3000W or less. In addition, in the second control, the level of the electrical bias EB can be constant. Alternatively, in the second control, the level of the electrical bias EB can be increased in stages or continuously. Alternatively, in the second control, the level of the electrical bias EB can be reduced in stages or continuously.

[0144] Furthermore, the control unit 2 executes a third control of a second cycle CYB2 which repeatedly includes the first control and the second control. The repetition frequency of the second cycle CYB2 is lower than the repetition frequency of the first cycle CYB1. The repetition frequency of the second cycle CYB2 may be greater than 1 Hz and less than 50 kHz. The repetition frequency of the second cycle CYB2 may be greater than 10 Hz and may be less than 2.1 kHz. In addition, the repetition frequency of the second control is the same as the repetition frequency of the second cycle CYB2.

[0145] The second cycle CYB2 may further include a fourth control performed before the first control. In the fourth control, the control unit 2 controls the high-frequency power source 31 to supply the source high-frequency power RF to generate plasma from the above-mentioned processing gas. The power level of the source high-frequency power RF in the fourth control may be higher than the power level of the source high-frequency power RF used in the repetition of the first cycle CYB1. In addition, the fourth control may be included in the first cycle CYB1, and may also be performed in the first cycle CYB1 before the control corresponding to the step STBb1 described later.

[0146] Furthermore, the second cycle CYB2 may further include a fifth control performed after the second control. In the fifth control, the control unit 2 controls the high frequency power source 31 and the bias power source 32 to stop the supply of the source high frequency power RF and the supply of the electric bias EB. In the fifth control, the control unit 2 may control the exhaust system 40 to exhaust the reaction product from the chamber 10.

[0147] Furthermore, the second cycle CYB2 may include the sixth control instead of the fifth control, or may include the sixth control in addition to the fifth control. In the sixth control, the control unit 2 controls the high frequency power source 31 and the bias power source 32 to stop the supply of the electric bias voltage EB while the source high frequency power RF is supplied. The sixth control may be performed at least one of before and after the second control.

[0148] Below, reference Fig. 9 and Fig.10 and Fig.11 (a)~ Fig.11 (c) and Fig.12 (a)~ Fig.12 (d) Method MTB is described. Furthermore, control of each unit of the plasma processing apparatus 1 by the control unit 2 is also described. Fig.11 (a)~ Fig.11 (c) are partial enlarged cross-sectional views of a substrate in one example related to each step of the etching method according to still another exemplary embodiment. Fig.12 (a)~ Fig.12 (d) are diagrams showing deposits grown in an etching method according to another exemplary embodiment. Hereinafter, the method MTB will be described using the plasma processing apparatus 1 as an example. In addition, the method MTB may be performed using a plasma processing apparatus different from the plasma processing apparatus 1.

[0149] like Fig. 9 As shown, the method MTB includes steps STBa, STBb and STBc. The method MTB may further include at least one of steps STBd and STBe.

[0150] In step STBa, a substrate W is prepared on the substrate support 11 in the chamber 10 of the plasma processing apparatus 1 . The steps of the method MTB performed after step STBa are performed with the substrate W mounted on the substrate support 11 .

[0151] like Fig.11As shown in (a), the substrate W to which the method MTB is applied includes a film EF and a mask MHM. The substrate W may further include a base region UR. The film EF is a film etched in the method MTB. The film EF is disposed on the base region UR. The film EF may be a silicon-containing film or a carbon-containing film. The film EF may be a dielectric film containing silicon and oxygen. The film EF may be a low dielectric constant film such as a SiOC film or a SiOCH film. Alternatively, the film EF may be an organic film. The mask MHM is disposed on the film EF. The mask MHM has a pattern transferred to the film EF by etching. That is, the mask MHM provides one or more openings. The mask MHM may be a metal hard mask. The mask MHM may be formed of titanium (e.g., titanium nitride), tungsten, molybdenum or ruthenium. The mask MHM may be formed of other metal-containing materials. The surface of the mask MHM may be exposed or covered by an organic film. Alternatively, the mask MHM may be a resist mask such as an EUV resist mask or an ArF resist mask.

[0152] Step STBd is performed after step STBa and before step STBb. Step STBd is performed during period PB1 (refer to Fig.10 ) is performed. In step STBd, plasma is generated in chamber 10 by a processing gas. The processing gas is a gas having deposition properties. The processing gas includes a fluorine-containing gas. The processing gas may include a gas component containing fluorine and carbon. The gas component may be, for example, C 4 F 8 The processing gas may further include one or more of nitrogen, an oxygen-containing gas (e.g., oxygen) and a rare gas (e.g., Ar gas). In step STBd, plasma is ignited in the chamber 10 to generate free radicals from the gas components of the processing gas.

[0153] In step STBd, the control unit 2 controls the gas supply unit 20 so as to supply the processing gas into the chamber 10. In step STBd, the control unit 2 controls the exhaust system 40 so as to set the pressure in the chamber 10 to a specified pressure. In step STBd, the control unit 2 controls the high-frequency power supply 31 so as to supply the source high-frequency power RF to the high-frequency electrode to generate plasma from the processing gas. In one embodiment, the power level of the source high-frequency power RF used in step STBd may be higher than the power level of the source high-frequency power RF used in the later steps STBb and STBc. In step STBd, the control unit 2 may control the bias power supply 32 so as not to supply the electrical bias EB to the bias electrode. Alternatively, in step STBd, the control unit 2 may control the bias power supply 32 so as to supply the electrical bias EB to the bias electrode.

[0154] Next, in the method MTB, step STBb is performed. In one embodiment, step STBb is performed after step STBd. In step STBb, the first cycle CYB1 is repeated. The first cycle CYB1 includes step STBb1 and step STBb2. The first cycle CYB1 may further include step STBf.

[0155] Process STBb1 in period PB2 (reference Fig.10 ) is performed. In addition, step STBb2 is performed during period PB3 (reference Fig.10 ) is performed. Period PB3 is a period immediately following period PB2. In step STBb1, a deposit DP (reference Fig.12 (a)) The deposit DP is supplied from the plasma generated from the above-mentioned process gas in the chamber 10. That is, the process gas used in the step STBd may be the same as the process gas used in the step STBb1. The deposit DP may contain carbon and fluorine.

[0156] In step STBb1, the control unit 2 controls the gas supply unit 20 to supply the processing gas into the chamber 10. In step STBb1, the control unit 2 controls the exhaust system 40 to set the pressure in the chamber 10 to a specified pressure. In step STBb1, the control unit 2 controls the high-frequency power source 31 to supply the source high-frequency power RF to the high-frequency electrode to generate plasma from the processing gas. In one embodiment, the power level (power level LB) of the source high-frequency power RF used in step STBb1 is RF1 In the step STBb1, the control unit 2 may control the bias power supply 32 so that the electric bias EB is not supplied to the bias electrode. Alternatively, in the step STBb1, the control unit 2 may control the bias power supply 32 so that the electric bias EB is supplied to the bias electrode.

[0157] Step STBf can be performed at least in parallel with step STBb1. That is, step STBf can be performed at least during period PB2. In step STBf, negative voltage NV is applied to the upper electrode. In step STBf, positive ions are attracted to the top plate 13p from the plasma in the chamber 10. As a result, the substance (e.g., silicon) constituting the top plate 13p is released. The substance released from the top plate 13p is bonded to the fluorine chemical species in the plasma, reducing the amount of the fluorine chemical species in the plasma.

[0158] In step STBf, the control unit 2 controls the power supply 35 so that the negative voltage NV is applied to the upper electrode. In addition, step STBf may be performed in period PB1 in addition to period PB2. Furthermore, in period PB4 described later, the negative voltage NV may be applied to the upper electrode.

[0159] In step STBb2, the deposit DP is modified by supplying ions from the plasma to the deposit DP. Fig.12 As shown in (b), the deposit MDP is generated from the deposit DP. The processing gas used in step STBb2 can be the same processing gas as the processing gas used in step STBb1. That is, in step STBb2, plasma can be generated from the processing gas having the above-mentioned deposition properties. In step STBb2, the energy of ions supplied from plasma to the deposit DP is higher than the energy of ions supplied from plasma to the substrate W in step STBb1. In step STBb2, ions with relatively high energy are supplied to the deposit DP, and unnecessary elements (for example, fluorine) are removed from the deposit DP. Therefore, in the deposit MDP obtained in step STBb2, many bonds with high bond energy (for example, carbon-to-carbon bonds) can be formed.

[0160] In step STBb2, the control unit 2 controls the gas supply unit 20 to supply the processing gas into the chamber 10. In step STBb2, the control unit 2 controls the exhaust system 40 to set the pressure in the chamber 10 to a specified pressure. In step STBb2, the control unit 2 controls the high-frequency power source 31 to supply the source high-frequency power RF to the high-frequency electrode to generate plasma from the processing gas. In one embodiment, the power level (power level LB) of the source high-frequency power RF used in step STBb2 is RF2 or S3) may be lower than the power level (power level S1) of the source high frequency power RF used in step STBd. In one embodiment, the power level (power level LB) of the source high frequency power RF used in step STBb2 RF2 or S3) can be the power level (power level LB) of the source high frequency power RF used in step STBb1 RF1or S2), or may be lower than this power level. In step STBb2, the control unit 2 controls the bias power supply 32 so that the electric bias EB is supplied to the bias electrode. In one embodiment, the level of the electric bias EB used in step STBb2 may be higher than the level of the electric bias EB used in step STBb1. In one embodiment, the level of the electric bias EB used in step STBb2 may be higher than the level of the electric bias EB used in step STBd. In addition, as described above, in at least one of step STBd and step STBb1, the supply of the electric bias EB may be stopped.

[0161] In the repetition of the first cycle CYB1 of step STBb, if Fig.12 As shown in (c), a sediment DP is formed on the sediment MDP, as Fig.12 As shown in (d), the deposit DP is modified and the thickness of the deposit MDP increases.

[0162] Next, in method MTB, step STBJ1 is performed. In step STBJ1, it is determined whether the stop condition is satisfied. In step STBJ1, the stop condition is satisfied when the number of executions of the first cycle CYB1 reaches a predetermined number of times. In step STBJ1, if it is determined that the stop condition is not satisfied, the first cycle CYB1 is performed again. In step STBJ1, if it is determined that the stop condition is satisfied, the repetition of the first cycle CYB1 ends. The result of repeating the first cycle CYB1 is as follows: Fig.11 As shown in (b), the surface of the substrate W is covered with the deposit MDP.

[0163] Next, in the method MTB, the step STBc is performed. The step STBc is performed after the first cycle CYB1 is repeated. The step STBc is performed during the period PB4 (refer to Fig.10 The period PB4 is a period after the period PB2 and the period PB3 are repeated alternately or a period immediately after the period PB2 and the period PB3 are repeated alternately.

[0164] In step STBc, the film EF is etched using plasma generated by the etching gas in the chamber 10. In step STBc, the plasma can be generated by the above-mentioned processing gas. That is, in step STBc, the same processing gas as that used in steps STBb1 and STBb2 can be used as the etching gas. Alternatively, the etching gas used in step STBc can be another gas selected in a manner to selectively etch the film EF.

[0165] In step STBc, the control unit 2 controls the gas supply unit 20 to supply the etching gas into the chamber 10. In step STBc, the control unit 2 controls the exhaust system 40 to set the pressure in the chamber 10 to a specified pressure. In step STBc, the control unit 2 controls the high-frequency power supply 31 to supply the source high-frequency power RF to the high-frequency electrode to generate plasma from the etching gas. In one embodiment, the power level (power level S4) of the source high-frequency power RF used in step STBc may be lower than the power level (power level S1) of the source high-frequency power RF used in step STBd. In one embodiment, the power level (power level S4) of the source high-frequency power RF used in step STBc may be lower than the power level (power level LB) of the source high-frequency power RF used in step STBb1. RF1 In addition, the power level of the source high frequency power RF used in step STBc (power level S4) can be different from the power level of the source high frequency power RF used in step STBb2 (power level LB RF2 In step STBc, the control unit 2 controls the bias power supply 32 so that the electric bias EB is supplied to the bias electrode. In one embodiment, the level (level B4) of the electric bias EB used in step STBc may be higher than the level (level LB) of the electric bias EB used in step STBb2. EB2 or B3).

[0166] In addition, in step STBc, the level of the electric bias EB may be constant (refer to Fig.10 Alternatively, in step STBc, the level of the electric bias EB may be increased stepwise or continuously (see FIG. Fig.10 (a) shows the time change from the level of the electric bias voltage EB in the period PB4 indicated by the solid line to the level of the electric bias voltage EB in the period PB4 indicated by the dotted line.) Alternatively, in step STBc, the level of the electric bias voltage EB may be reduced stepwise or continuously.

[0167] In the method MTB, the second cycle CYB2 including the step STBb and the step STBc is repeated. The second cycle CYB2 may further include the step STBd. In addition, the step STBd may be included in the first cycle CYB1, or may be performed before the step STBb1 in the first cycle CYB1.

[0168] In one embodiment, the second cycle CYB2 may further include a step STBe. The step STBe is performed after the step STBc. The step STBe is performed during the period PB5 (refer to Fig.10 ) is performed. The period PB5 is a period after the period PB4 or immediately following the period PB4.

[0169] In step STBe, the reaction product generated in step STBc is exhausted from the chamber 10. In step STBe, plasma may not be generated in the chamber 10.

[0170] In step STBe, the control unit 2 controls the exhaust system 40 to exhaust the chamber 10 and discharge the reaction product from the chamber 10. In step STBe, the control unit 2 may control the high frequency power source 31 to stop supplying the source high frequency power RF. In step STBe, the control unit 2 may control the bias power source 32 to stop supplying the electric bias EB.

[0171] In one embodiment, the second cycle CYB2 may include a step STBg instead of the step STBe, or may include the step STBg in addition to the step STBe. In the step STBg, the supply of the electric bias EB is stopped while the source high frequency power RF is supplied (see Fig.10 The step STBg can be performed at least either before or after the step STBc.

[0172] The method MTB also includes a step STBJ2. In the step STBJ2, it is determined whether the stop condition is satisfied. In the step STBJ2, the stop condition is satisfied when the number of executions of the second cycle CYB2 reaches a predetermined number of times. In the step STBJ2, if it is determined that the stop condition is not satisfied, the second cycle CYB2 is performed again. When it is determined that the stop condition is satisfied in the step STBJ2, the method MTB ends. In the method MTB, the result of repeating the second cycle CYB2 is as follows: Fig.11 As shown in (c), a recessed portion is formed on the film EF.

[0173] In the method MTB, as a result of repeating the steps STBb1 and STBb2, the thickness of the deposit MDP increases, and a modified deposit MDP having interatomic bonds with high bond energy is formed throughout the thickness direction. The deposit MDP protects the mask MHM from the etching effect of the step STBc. Therefore, according to the method MTB, the reduction of the mask MHM due to etching is suppressed.

[0174] In the method MTB, as the second cycle CYB2 is repeated, that is, according to the increase in the depth of the recessed portion formed in the film EF, the gas conditions and / or temperature conditions in each step of the second cycle CYB2 may be changed.

[0175] Furthermore, as the first cycle CYB1 is repeated, at least one of the power level of the source high frequency power RF and the level of the electric bias EB may be changed in each step of the first cycle CYB1. For example, in each step, at least one of the power level of the source high frequency power RF and the level of the electric bias EB may be set to a relatively low level to repeat the first cycle CYB1. Then, the at least one level may be set to a relatively high level to repeat the first cycle CYB1.

[0176] Below, refer again Figure 7 and Figure 8 (a)~ Figure 8 (d) Method MTA in which several steps of method MTB are performed is described. In a substrate W to which method MTA described below is applied, mask MHM is the above-mentioned metal hard mask.

[0177] In step STa of method MTA, similarly to step STBa of method MTB, a substrate W is prepared on substrate support 11 in chamber 10 of plasma processing apparatus 1 (see Figure 8 (a)) The steps of the method MTA performed after the step STBa are performed in a state where the substrate W is placed on the substrate support 11. After the step STa, the steps ST1 and ST2 are performed as described above.

[0178] Next, step ST3 is performed. In step ST3, the film EF is etched. In step ST3, the above-mentioned steps STBb and SBTc are performed. In step ST3, at least one of the above-mentioned steps STBd, STBe, STBf, and STBg may be further performed. In one embodiment, in step ST3, the first cycle CYB1 may be repeated, and the second cycle CYB2 may be repeated. Through step ST3, as Figure 8 As shown in (c), the pattern of the organic film OF is transferred to the film EF, thereby forming a recessed portion in the film EF. Next, as described above, step ST4 is performed.

[0179] Next, step ST5 is performed. In step ST5, Figure 8 As shown in (d), the film EF is further etched in a manner to increase the depth of the recess. In step ST5, the above-mentioned steps STBb and STBc are performed. In step ST5, at least one of the above-mentioned steps STBd, STBe, STBf, and STBg may be further performed. In one embodiment, in step ST5, the first cycle CYB1 may be repeated, and the second cycle CYB2 may be repeated.

[0180] In addition, in the step STBc performed in the method MTA, as described above, the level of the electric bias EB can be increased stepwise or continuously. In this case, the etching of the film EF in the step STBc includes etching caused by low-energy ions, so that damage to the mask MHM can be suppressed when etching the film EF, and clogging (blocking) of the recessed portion in the organic film OF can be suppressed. Therefore, in the next first cycle CYB1, the protection of the mask MHM based on the deposit MDP can be promoted. Therefore, the selectivity of the etching of the film EF relative to the mask MHM can be improved.

[0181] Alternatively, in the step STBc performed in the method MTA, as described above, the level of the electric bias EB can be reduced in stages or continuously. In this case, the total amount of energy of the ions used in the etching of the film EF in the step STBc is suppressed, so that damage to the mask MHM can be suppressed when etching the film EF, and clogging (blocking) of the recessed portion in the organic film OF can be suppressed. Therefore, in the next first cycle CYB1, the protection of the mask MHM by the deposit MDP can be promoted. Therefore, the selectivity of the etching of the film EF relative to the mask MHM can be improved.

[0182] Next, the fourth and fifth evaluation experiments conducted to evaluate the MTB method are described. Figure 7 (a) A sample substrate having the structure shown. In the sample substrate, the mask MHM is formed of titanium nitride. Then, in the fourth and fifth evaluation experiments, the plasma processing device 1 was used to apply the steps ST1 to ST3 to the sample substrate. However, in the fourth evaluation experiment, the bias level of the period PB4 was constant, and in the fifth evaluation experiment, the period PB4 was divided into two stages to increase the bias level in stages. The following shows the conditions of the fourth and fifth evaluation experiments.

[0183] (Conditions of the 4th and 5th evaluation experiments)

[0184] Processing gas: nitrogen, hydrogen, Ar gas, CF 4 Gas, C 4 F 8 Gas mixture

[0185] Source high frequency power of STBb1 in each step of the 4th and 5th evaluation experiments: 30 W

[0186] Bias high frequency power of STBb2 in each step of the 4th and 5th evaluation experiments: 30 W

[0187] Repetition frequency of step STBb1 and step STBb2 in the fourth and fifth evaluation experiments: 625 Hz

[0188] Source high frequency power of STBc in the fourth and fifth evaluation experiments: 30 W

[0189] The bias high frequency power of STBc in the fourth evaluation experiment: 700W

[0190] The bias high frequency power of STBc in the fifth evaluation experiment was increased stepwise from 200W to 700W

[0191] In the 4th and 5th evaluation experiments, the selectivity between the etching of the mask MHM and the etching of the film EF was obtained. In addition, the selectivity is the value obtained by dividing the reduction in the thickness of the mask MHM by the depth of the recess formed in the film EF. As a result, in the 4th evaluation experiment, the selectivity was 21.0, and in the 5th evaluation experiment, the selectivity was 25.3. In addition, the width of the recess at the top of the organic film OF was 6.7nm in the 4th evaluation experiment and 7.3nm in the 5th evaluation experiment. In this way, a high selectivity was obtained in any of the 4th and 5th evaluation experiments. In addition, in the 5th evaluation experiment, the width of the recess in the organic film OF was large and the selectivity was high compared with the 4th evaluation experiment. Therefore, it was confirmed that by gradually increasing the level of the electrical bias in the process STBc and gradually increasing the energy of the ions, the clogging (blocking) of the recess in the organic film OF can be suppressed and the selectivity can be improved.

[0192] Various exemplary embodiments have been described above, but the present invention is not limited to the exemplary embodiments described above, and various additions, omissions, substitutions, and changes may be made. Furthermore, elements in different embodiments may be combined to form other embodiments.

[0193] For example, the level of the negative voltage NV may be constant in the first cycle CYB1 , and the level of the negative voltage NV may be constant in the second cycle CYB2 .

[0194] Here, various exemplary embodiments included in the present invention are described in the following [E1] to [E18], [F1] to [F14], and [G1] to [G19].

[0195] [E1]

[0196] An etching method, comprising:

[0197] (a) step of preparing a substrate on a substrate support in a chamber of a plasma processing apparatus, the substrate including a dielectric film containing silicon and oxygen and a metal hard mask disposed on the dielectric film;

[0198] (b) forming a deposit on the substrate, the deposit being supplied from plasma generated from a processing gas in the chamber, the processing gas including a gas component containing fluorine and carbon;

[0199] (c) a step of modifying the deposit by supplying ions from a plasma generated from the process gas to the deposit; and

[0200] (d) step of etching the dielectric film using the plasma generated in the chamber after step (c),

[0201] The power level of the source high frequency power used in (c) to generate the plasma from the processing gas is lower than the power level of the source high frequency power used in (b) to generate the plasma from the processing gas,

[0202] the level of the electrical bias supplied to the substrate supporting portion in (c) is higher than the level of the electrical bias supplied to the substrate supporting portion in (b), or the electrical bias is not supplied to the substrate supporting portion in (b),

[0203] The level of the electrical bias supplied to the substrate supporting portion in (d) is higher than the level of the electrical bias supplied to the substrate supporting portion in (c).

[0204] [E2]

[0205] The etching method according to E1, wherein:

[0206] The energy of the ions supplied to the deposit in (c) is higher than the energy of the ions supplied to the substrate in (b).

[0207] [E3]

[0208] The etching method according to E1 or E2, wherein:

[0209] In order to generate the plasma used in the (d), the processing gas used in the (b) and (c) is used.

[0210] [E4]

[0211] The etching method according to any one of E1 to E3, further comprising:

[0212] (e) step, after (a) and before (b), generating plasma from the processing gas in the chamber,

[0213] The power level of the source high frequency power used in (e) to generate the plasma from the processing gas is higher than the power level of the source high frequency power used in each of (b) and (c) to generate the plasma from the processing gas.

[0214] [E5]

[0215] The etching method according to any one of E1 to E3, wherein

[0216] The cycle including (b), (c) and (d) is repeated.

[0217] [E6]

[0218] The etching method according to E5, wherein

[0219] The cycle also includes:

[0220] (e) step, before (b), generating plasma from the processing gas in the chamber,

[0221] The power level of the source high frequency power used in (e) to generate the plasma from the processing gas is higher than the power level of the source high frequency power used in each of (b) and (c) to generate the plasma from the processing gas.

[0222] [E7]

[0223] The etching method according to E5, wherein

[0224] The cycle also includes:

[0225] (f) step, after step (d), discharging the reaction product generated in step (d) from the chamber,

[0226] In the (f) above, plasma is not generated in the chamber.

[0227] [E8]

[0228] The etching method according to any one of E1 to E7, wherein

[0229] The metal hard mask includes at least one metal selected from the group consisting of titanium, tungsten, molybdenum, and ruthenium.

[0230] [E9]

[0231] A plasma processing device for etching a dielectric film of a substrate, wherein the substrate comprises the dielectric film containing silicon and oxygen and a metal hard mask disposed on the dielectric film.

[0232] The plasma processing device comprises:

[0233] Chamber;

[0234] A substrate supporting portion, disposed in the chamber;

[0235] a gas supply unit configured to supply gas into the chamber;

[0236] a high frequency power source configured to supply high frequency power to generate plasma in the chamber;

[0237] a bias power supply configured to supply an electrical bias voltage to the substrate support portion; and

[0238] a control unit configured to control the gas supply unit, the high frequency power supply, and the bias power supply,

[0239] The control unit is configured as follows:

[0240] In a state where the substrate is placed on the substrate supporting portion,

[0241] In the first step, in order to form a deposit on the substrate, the gas supply unit and the high frequency power supply are controlled so that plasma is generated in the chamber from a processing gas containing a gas component containing fluorine and carbon.

[0242] In the second step, in order to modify the deposit, the gas supply unit, the high frequency power supply, and the bias power supply are controlled so that ions are supplied to the deposit from the plasma generated from the processing gas.

[0243] In the third step, after the deposit is modified, the gas supply unit, the high frequency power supply, and the bias power supply are controlled so that the dielectric film is etched using the plasma generated in the chamber.

[0244] The control unit is configured as follows:

[0245] The power level of the source high frequency power used in the second step to generate the plasma from the processing gas is set to a level lower than the power level of the source high frequency power used in the first step to generate the plasma from the processing gas,

[0246] setting the level of the electrical bias supplied to the substrate supporting portion in the second step to a level higher than the level of the electrical bias supplied to the substrate supporting portion in the first step, or not supplying the electrical bias to the substrate supporting portion in the first step,

[0247] The level of the electrical bias supplied to the substrate supporting portion in the third step is set to a level higher than the level of the electrical bias supplied to the substrate supporting portion in the second step.

[0248] [E10]

[0249] An etching method, comprising:

[0250] (a) step of preparing a substrate on a substrate support in a chamber of a plasma processing apparatus, the substrate including a film and a mask disposed on the film;

[0251] (b) step, repeating the first cycle, the first cycle comprising:

[0252] (b1) forming a deposit on the substrate, the deposit being supplied to the substrate from plasma generated from a processing gas having a deposition property in the chamber; and

[0253] (b2) step of modifying the deposit by supplying ions from a plasma to the deposit; and

[0254] (c) etching the film using the plasma generated in the chamber,

[0255] Repeating the second cycle including the steps (b) and (c),

[0256] The power level of the source high frequency power used to generate plasma during the period (b1) in the first cycle is higher than the power level of the source high frequency power during the period (b2) in the first cycle.

[0257] The level of the electric bias supplied to the substrate support portion during (b2) in the first cycle for introducing ions into the substrate is higher than the level of the electric bias supplied to the substrate support portion during (b1) in the first cycle, or the electric bias is not supplied to the substrate support portion in (b1),

[0258] The level of the electrical bias supplied to the substrate supporting portion in the (c) is higher than the level of the electrical bias supplied to the substrate supporting portion in the (b2).

[0259] [E11]

[0260] The etching method according to E10, wherein:

[0261] The energy of the ions supplied to the deposit in the (b2) is higher than the energy of the ions supplied to the substrate in the (b1).

[0262] [E12]

[0263] The etching method according to E10 or E11, wherein

[0264] The second cycle also includes:

[0265] (d) step, before (b), generating plasma from the processing gas in the chamber.

[0266] [E13]

[0267] The etching method according to E12, wherein

[0268] In the (d) step, the power level of the source high frequency power supplied to generate the plasma from the processing gas in the chamber is higher than the power level of the source high frequency power used in the first cycle.

[0269] [E14]

[0270] The etching method according to E10 or E11, wherein

[0271] The first cycle also includes:

[0272] (d) step, before the step (b1), generating plasma from the processing gas in the chamber.

[0273] [E15]

[0274] The etching method according to any one of E10 to E14, wherein

[0275] The second cycle also includes:

[0276] (e) step, after step (c), discharging the reaction product generated in step (c) from the chamber,

[0277] In the (e), plasma is not generated in the chamber.

[0278] [E16]

[0279] The etching method according to any one of E10 to E14, wherein

[0280] The second cycle also includes:

[0281] (g) step of stopping supplying an electrical bias voltage for introducing ions into the substrate while supplying a source high frequency power for generating plasma in the chamber,

[0282] The (g) is performed at least either before or after the (c).

[0283] [E17]

[0284] The etching method according to any one of E10 to 16, wherein

[0285] The plasma generated in the (b2) is generated from the same process gas as the process gas used in the (b1).

[0286] [E18]

[0287] The etching method according to any one of E10 to E17, wherein

[0288] The plasma generated in the (c) is generated from the same process gas as the process gas used in the (b1).

[0289] [E19]

[0290] The etching method according to any one of E10 to E18, wherein

[0291] In the (c), the level of the electrical bias supplied to the substrate supporting portion increases stepwise or continuously.

[0292] [F1]

[0293] An etching method, comprising:

[0294] (a) step of preparing a substrate on a substrate support in a chamber of a plasma processing apparatus, the substrate including a dielectric film containing silicon and oxygen and a metal hard mask disposed on the dielectric film;

[0295] (b) forming a deposit on the substrate, the deposit being supplied from plasma generated from a processing gas in the chamber, the processing gas including a gas component containing fluorine and carbon;

[0296] (c) a step of modifying the deposit by supplying ions from a plasma generated from the process gas to the deposit; and

[0297] (d) step of etching the dielectric film using the plasma generated in the chamber after step (c),

[0298] The energy of the ions supplied to the deposit in (c) is higher than the energy of the ions supplied to the substrate in (b).

[0299] In an embodiment of [F1], in step (b), a deposit containing carbon and fluorine is formed on a substrate. In step (c), ions having relatively high energy are supplied to the deposit from a plasma generated from the same processing gas as that used in step (b), so that the deposit is modified. Through step (c), many carbon-to-carbon bonds having high bond energy can be formed in the deposit. The deposit modified in this way protects the metal hard mask from the etching of step (d). Therefore, according to an embodiment of [F1], the reduction of the metal hard mask caused by etching can be suppressed.

[0300] [F2]

[0301] The etching method according to [F1], wherein:

[0302] In order to generate the plasma used in the (d), the processing gas used in the (b) and (c) is used.

[0303] [F3]

[0304] The etching method according to [F1] or [F2], further comprising:

[0305] (e) step, after (a) and before (b), generating plasma from the processing gas in the chamber,

[0306] The power level of the source high frequency power used in (e) to generate the plasma from the processing gas is higher than the power level of the source high frequency power used in each of (b) and (c) to generate the plasma from the processing gas.

[0307] [F4]

[0308] The etching method according to [F1] or [F2], wherein:

[0309] The cycle including (b), (c) and (d) is repeated.

[0310] [F5]

[0311] The etching method according to [F4], wherein:

[0312] The cycle also includes:

[0313] (f) step, before (b), generating plasma from the processing gas in the chamber,

[0314] The power level of the source high frequency power used in (e) to generate the plasma from the processing gas is higher than the power level of the source high frequency power used in each of (b) and (c) to generate the plasma from the processing gas.

[0315] [F6]

[0316] The etching method according to [F4] or [F5], wherein:

[0317] The cycle also includes:

[0318] (f) step, after step (d), discharging the reaction product generated in step (d) from the chamber,

[0319] In the (f) above, plasma is not generated in the chamber.

[0320] [F7]

[0321] The etching method according to any one of [F1] to [F6], wherein

[0322] The level of the electrical bias supplied to the substrate supporting portion in (d) is higher than the level of the electrical bias supplied to the substrate supporting portion in (c).

[0323] [F8]

[0324] The etching method according to any one of [F1] to [F7], wherein:

[0325] The power level of the source high frequency power used in (c) to generate the plasma from the processing gas is lower than the power level of the source high frequency power used in (b) to generate the plasma from the processing gas,

[0326] The level of the electrical bias supplied to the substrate supporting portion in (c) is higher than the level of the electrical bias supplied to the substrate supporting portion in (b), or the electrical bias is not supplied to the substrate supporting portion in (b).

[0327] [F9]

[0328] The etching method according to any one of [F1] to [F8], wherein:

[0329] The plasma processing device is a capacitively coupled plasma processing device and includes an upper electrode disposed above the substrate support portion.

[0330] The etching method further includes a step of applying a negative voltage to the upper electrode when performing the step (b).

[0331] [F10]

[0332] The etching method according to [F9], wherein:

[0333] The upper electrode includes a top plate that divides the inner space of the chamber,

[0334] The top plate comprises silicon.

[0335] [F11]

[0336] The etching method according to any one of [F1] to [F10], wherein

[0337] The gas component used in (b) and (c) is fluorocarbon.

[0338] [F12]

[0339] The etching method according to any one of [F1] to [F11], wherein

[0340] The metal hard mask is formed of titanium nitride.

[0341] [F13]

[0342] The etching method according to any one of [F1] to [F12], wherein:

[0343] The dielectric film includes a low dielectric constant film.

[0344] [F14]

[0345] A plasma processing device for etching a dielectric film of a substrate, wherein the substrate comprises the dielectric film containing silicon and oxygen and a metal hard mask disposed on the dielectric film.

[0346] The plasma processing device comprises:

[0347] Chamber;

[0348] A substrate supporting portion, disposed in the chamber;

[0349] a gas supply unit configured to supply gas into the chamber;

[0350] a high frequency power source configured to supply high frequency power to generate plasma in the chamber;

[0351] a bias power supply configured to supply an electrical bias voltage to the substrate support portion; and

[0352] a control unit configured to control the gas supply unit, the high frequency power supply, and the bias power supply,

[0353] The control unit is configured as follows:

[0354] In a state where the substrate is placed on the substrate supporting portion,

[0355] In order to form a deposit on the substrate, the gas supply unit and the high frequency power supply are controlled so that plasma is generated in the chamber from a processing gas, the processing gas including a gas component containing fluorine and carbon,

[0356] In order to modify the deposit, the gas supply unit, the high frequency power supply, and the bias power supply are controlled so that ions are supplied to the deposit from the plasma generated from the processing gas.

[0357] After the deposit is modified, the gas supply unit, the high frequency power supply, and the bias power supply are controlled so that the dielectric film is etched using the plasma generated in the chamber.

[0358] The control unit controls the high frequency power supply and / or the bias power supply so that the energy of ions supplied to the deposit for modifying the deposit is higher than the energy of ions supplied to the substrate for forming the deposit.

[0359] [G1]

[0360] An etching method, comprising:

[0361] (a) step of preparing a substrate on a substrate support in a chamber of a plasma processing apparatus, the substrate including a film and a mask disposed on the film;

[0362] (b) step, repeating the first cycle, the first cycle comprising:

[0363] (b1) forming a deposit on the substrate, the deposit being supplied to the substrate from plasma generated from a processing gas having a deposition property in the chamber; and

[0364] (b2) step of modifying the deposit by supplying ions from a plasma to the deposit; and

[0365] (c) etching the film using the plasma generated in the chamber,

[0366] Repeating the second cycle including the steps (b) and (c),

[0367] The energy of the ions supplied to the deposit in the (b2) is higher than the energy of the ions supplied to the substrate in the (b1).

[0368] In the embodiment of [G1], in step (b1), a deposit containing carbon and fluorine is formed on a substrate. In step (b2), ions with relatively high energy are supplied to the deposit, so that the deposit is modified. As a result of repeating such steps (b1) and (b2), the thickness of the deposit increases, and a modified deposit having interatomic bonds with high bond energy is formed throughout the entire deposit. The mask is protected from the etching of step (c) by the deposit modified in this way. Therefore, according to the embodiment of [G1], the reduction of the mask caused by etching can be suppressed.

[0369] [G2]

[0370] The etching method according to [G1], wherein:

[0371] The first cycle includes sequentially setting a power level of a source high frequency power for generating plasma in the chamber and a level of an electrical bias for introducing ions into the substrate to two different levels.

[0372] [G3]

[0373] The etching method according to [G2], wherein:

[0374] The power level of the source high frequency power during the period (b1) in the first cycle is higher than the power level of the source high frequency power during the period (b2) in the first cycle.

[0375] The level of the electrical bias during the period (b2) in the first cycle is higher than the level of the electrical bias during the period (b1) in the first cycle.

[0376] [G4]

[0377] The etching method according to any one of [G1] to [G3], wherein

[0378] The second cycle also includes:

[0379] (d) step, before (b), generating plasma from the processing gas in the chamber.

[0380] [G5]

[0381] The etching method according to [G4], wherein:

[0382] In the (d) step, the power level of the source high frequency power supplied to generate the plasma from the processing gas in the chamber is higher than the power level of the source high frequency power used in the first cycle.

[0383] [G6]

[0384] The etching method according to any one of [G1] to [G3], wherein

[0385] The first cycle also includes:

[0386] (d) step, before the step (b1), generating plasma from the processing gas in the chamber.

[0387] [G7]

[0388] The etching method according to any one of [G1] to [G6], wherein

[0389] The plasma processing device is a capacitively coupled plasma processing device and includes an upper electrode disposed above the substrate support portion.

[0390] The etching method further includes a step of applying a negative voltage to the upper electrode when performing the step (b1).

[0391] [G8]

[0392] The etching method according to [G7], wherein:

[0393] When performing the step (b2), the negative voltage is not applied to the upper electrode.

[0394] [G9]

[0395] The etching method according to [G5], wherein:

[0396] The plasma processing device is a capacitively coupled plasma processing device and includes an upper electrode disposed above the substrate support portion.

[0397] The etching method further includes a step of applying a negative voltage to the upper electrode when performing the step (d).

[0398] [G10]

[0399] The etching method according to any one of [G7] to [G9], wherein

[0400] The upper electrode includes a top plate that divides the inner space of the chamber,

[0401] The top plate comprises silicon.

[0402] [G11]

[0403] The etching method according to any one of [G1] to [G10], wherein

[0404] The second cycle also includes:

[0405] (e) step, after step (c), discharging the reaction product generated in step (c) from the chamber,

[0406] In the (e), plasma is not generated in the chamber.

[0407] [G12]

[0408] The etching method according to any one of [G1] to [G10], wherein

[0409] The second cycle also includes:

[0410] (g) step of stopping supplying an electrical bias voltage for introducing ions into the substrate while supplying a source high frequency power for generating plasma in the chamber,

[0411] The (g) is performed at least either before or after the (c).

[0412] [G13]

[0413] The etching method according to any one of [G1] to [G12], wherein

[0414] The plasma generated in the (b2) is generated from the same process gas as the process gas used in the (b1).

[0415] [G14]

[0416] The etching method according to any one of [G1] to [G13], wherein

[0417] The plasma generated in the (c) is generated from the same process gas as the process gas used in the (b1).

[0418] [G15]

[0419] The etching method according to any one of [G1] to [G14], wherein

[0420] The film is a silicon-containing film or a carbon-containing film,

[0421] The process gas includes a fluorine-containing gas.

[0422] [G16]

[0423] The etching method according to [G15], wherein

[0424] The fluorine-containing gas is a fluorocarbon gas.

[0425] [G17]

[0426] The etching method according to any one of [G1] to [G16], wherein

[0427] The energy of the ions supplied to the substrate in (c) is higher than the energy of the ions supplied to the deposit in (b2).

[0428] [G18]

[0429] A plasma processing device comprising:

[0430] Chamber;

[0431] A substrate supporting portion, disposed in the chamber;

[0432] a high frequency power source configured to supply high frequency power to generate plasma in the chamber;

[0433] a bias power supply configured to supply an electrical bias voltage to the substrate support portion; and

[0434] a control unit configured to control the high frequency power supply and the bias power supply,

[0435] The control unit is configured as follows:

[0436] (a) repeating a first cycle in a state where a deposition-type processing gas is supplied into the chamber, wherein the first cycle controls the high-frequency power source and the bias power source so as to sequentially change at least one of the power level of the source high-frequency power and the level of the electrical bias voltage to two different levels;

[0437] (b) after repeating the first cycle, controlling the high frequency power supply and the bias power supply so as to supply the source high frequency power and the electrical bias to generate a plasma of the etching gas; and

[0438] (c) Repeating a second cycle including the steps (a) and (b).

[0439] [G19]

[0440] An etching method, comprising:

[0441] (a) step of preparing a substrate on a substrate support in a chamber of a plasma processing apparatus, the substrate including a film and a mask disposed on the film;

[0442] (d) step of generating plasma in the chamber from a processing gas having a deposition property;

[0443] (b) step, repeating the first cycle after the step (d), the first cycle comprising:

[0444] (b1) forming a deposit on the substrate, the deposit being supplied to the substrate from plasma generated from the processing gas in the chamber; and

[0445] (b2) step of modifying the deposit by supplying ions from a plasma to the deposit; and

[0446] (c) a step of etching the film using the plasma generated in the chamber after the first cycle,

[0447] Repeating the second cycle including (d), (b) and (c),

[0448] In (d), the power level S1 of the source high-frequency power supplied to generate the plasma from the processing gas in the chamber, the power level S2 of the source high-frequency power during (b1) in the first cycle, the power level S3 of the source high-frequency power during (b2) in the first cycle and the level B3 of the electrical bias for introducing ions into the substrate, and the power level S4 of the source high-frequency power and the level B4 of the electrical bias during (c) satisfy: S1>S2>S3=S4, B3<B4.

[0449] [G20]

[0450] The etching method according to any one of G1 to G17 and G19, wherein:

[0451] In the (c), the level of the electrical bias supplied to the substrate supporting portion increases stepwise or continuously.

[0452] It can be understood from the above description that various embodiments of the present invention are described in this specification for the purpose of illustration, and various changes can be made without departing from the scope and gist of the present invention. Therefore, it is not intended to limit the various embodiments disclosed in this specification, and the true scope and gist are represented by the attached claims.

[0453] Explanation of symbols

[0454] 1 plasma processing device, 10 chamber, 11 substrate supporting part, 31 high frequency power supply, 32 bias power supply, W substrate, MHM mask, EF film.

Claims

1. An etching method, comprising: (a) step of preparing a substrate on a substrate support in a chamber of a plasma processing apparatus, the substrate including a dielectric film containing silicon and oxygen and a metal hard mask disposed on the dielectric film; (b) forming a deposit on the substrate, the deposit being supplied from plasma generated from a processing gas in the chamber, the processing gas including a gas component containing fluorine and carbon; (c) a step of modifying the deposit by supplying ions from a plasma generated from the process gas to the deposit; and (d) step of etching the dielectric film using the plasma generated in the chamber after step (c), The power level of the source high frequency power used in (c) to generate the plasma from the processing gas is lower than the power level of the source high frequency power used in (b) to generate the plasma from the processing gas, the level of the electrical bias supplied to the substrate supporting portion in (c) is higher than the level of the electrical bias supplied to the substrate supporting portion in (b), or the electrical bias is not supplied to the substrate supporting portion in (b), The level of the electrical bias supplied to the substrate supporting portion in (d) is higher than the level of the electrical bias supplied to the substrate supporting portion in (c).

2. The etching method according to claim 1, wherein: The energy of the ions supplied to the deposit in (c) is higher than the energy of the ions supplied to the substrate in (b).

3. The etching method according to claim 1, wherein: In order to generate the plasma used in the (d), the processing gas used in the (b) and (c) is used.

4. The etching method according to any one of claims 1 to 3, further comprising: (e) step, after (a) and before (b), generating plasma from the processing gas in the chamber, The power level of the source high frequency power used in (e) to generate the plasma from the processing gas is higher than the power level of the source high frequency power used in each of (b) and (c) to generate the plasma from the processing gas.

5. The etching method according to any one of claims 1 to 3, wherein: The cycle including (b), (c) and (d) is repeated.

6. The etching method according to claim 5, wherein: The cycle also includes: (e) step, before (b), generating plasma from the processing gas in the chamber, The power level of the source high frequency power used in (e) to generate the plasma from the processing gas is higher than the power level of the source high frequency power used in each of (b) and (c) to generate the plasma from the processing gas.

7. The etching method according to claim 5, wherein: The cycle also includes: (f) step, after step (d), discharging the reaction product generated in step (d) from the chamber, In the (f) above, plasma is not generated in the chamber.

8. The etching method according to any one of claims 1 to 3, wherein: The metal hard mask includes at least one metal selected from the group consisting of titanium, tungsten, molybdenum, and ruthenium.

9. A plasma processing apparatus for etching a dielectric film of a substrate, the substrate comprising the dielectric film containing silicon and oxygen and a metal hard mask disposed on the dielectric film, The plasma processing device comprises: Chamber; A substrate supporting portion, disposed in the chamber; a gas supply unit configured to supply gas into the chamber; a high frequency power source configured to supply high frequency power to generate plasma in the chamber; a bias power supply configured to supply an electrical bias voltage to the substrate support portion; and a control unit configured to control the gas supply unit, the high frequency power supply, and the bias power supply, The control unit is configured as follows: In a state where the substrate is placed on the substrate supporting portion, In the first step, in order to form a deposit on the substrate, the gas supply unit and the high frequency power supply are controlled so that plasma is generated in the chamber from a processing gas containing a gas component containing fluorine and carbon. In the second step, in order to modify the deposit, the gas supply unit, the high frequency power supply, and the bias power supply are controlled so that ions are supplied to the deposit from the plasma generated from the processing gas. In the third step, after the deposit is modified, the gas supply unit, the high frequency power supply, and the bias power supply are controlled so that the dielectric film is etched using the plasma generated in the chamber. The control unit is configured as follows: The power level of the source high frequency power used in the second step to generate the plasma from the processing gas is set to a level lower than the power level of the source high frequency power used in the first step to generate the plasma from the processing gas, setting the level of the electrical bias supplied to the substrate supporting portion in the second step to a level higher than the level of the electrical bias supplied to the substrate supporting portion in the first step, or not supplying the electrical bias to the substrate supporting portion in the first step, The level of the electrical bias supplied to the substrate supporting portion in the third step is set to a level higher than the level of the electrical bias supplied to the substrate supporting portion in the second step.

10. An etching method, comprising: (a) step of preparing a substrate on a substrate support in a chamber of a plasma processing apparatus, the substrate including a film and a mask disposed on the film; (b) step, repeating the first cycle, the first cycle comprising: (b1) forming a deposit on the substrate, the deposit being supplied to the substrate from plasma generated from a processing gas having a deposition property in the chamber; and (b2) step of modifying the deposit by supplying ions from a plasma to the deposit; as well as (c) etching the film using the plasma generated in the chamber, Repeating the second cycle including the steps (b) and (c), The power level of the source high frequency power used to generate plasma during the period (b1) in the first cycle is higher than the power level of the source high frequency power during the period (b2) in the first cycle. The level of the electric bias supplied to the substrate support portion during (b2) in the first cycle for introducing ions into the substrate is higher than the level of the electric bias supplied to the substrate support portion during (b1) in the first cycle, or the electric bias is not supplied to the substrate support portion in (b1), The level of the electrical bias supplied to the substrate supporting portion in the (c) is higher than the level of the electrical bias supplied to the substrate supporting portion in the (b2).

11. The etching method according to claim 10, wherein: The energy of the ions supplied to the deposit in the (b2) is higher than the energy of the ions supplied to the substrate in the (b1).

12. The etching method according to claim 10, wherein: The second cycle also includes: (d) step, before (b), generating plasma from the processing gas in the chamber.

13. The etching method according to claim 12, wherein: In the (d) step, the power level of the source high frequency power supplied to generate the plasma from the processing gas in the chamber is higher than the power level of the source high frequency power used in the first cycle.

14. The etching method according to claim 10, wherein: The first cycle also includes: (d) step, before the step (b1), generating plasma from the processing gas in the chamber.

15. The etching method according to any one of claims 10 to 14, wherein: The second cycle also includes: (e) step, after step (c), discharging the reaction product generated in step (c) from the chamber, In the (e), plasma is not generated in the chamber.

16. The etching method according to any one of claims 10 to 14, wherein: The second cycle also includes: (g) step of stopping supplying an electrical bias voltage for introducing ions into the substrate while supplying a source high frequency power for generating plasma in the chamber, The (g) is performed at least either before or after the (c).

17. The etching method according to any one of claims 10 to 14, wherein: The plasma generated in the (b2) is generated from the same process gas as the process gas used in the (b1).

18. The etching method according to any one of claims 10 to 14, wherein: The plasma generated in the (c) is generated from the same process gas as the process gas used in the (b1).

19. The etching method according to any one of claims 10 to 14, wherein: In the (c), the level of the electrical bias supplied to the substrate supporting portion increases stepwise or continuously.

Images