Plasma processing apparatus and plasma processing method

Abstract

In the disclosed plasma processing apparatus, a control unit causes repetition of a cycle. The cycle includes the steps of: supplying a pulse of high-frequency power from a high-frequency power source to generate plasma from the gas in the chamber; and supplying an electrically biased pulse from a bias power source to the substrate support portion. The electrically biased pulse includes a DC voltage pulse periodically generated at a bias frequency of 1 MHz or less. The repetition frequency of the cycle is 5 kHz or more. The start timing of the electrically biased pulse is at the same time as or earlier than the stop timing of the source high-frequency power pulse. The stopping timing of the electrically biased pulse is later than the stopping timing of the high-frequency power source pulse.

Description

Technical Field

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

[0002] A plasma processing device is used for etching a film of a substrate. The plasma processing device includes a chamber, a substrate support, a source high frequency power supply, and a bias high frequency power supply. The substrate support is arranged in the chamber. The source high frequency power supply supplies source high frequency power to generate plasma from gas in the chamber. The bias high frequency power supply supplies bias high frequency power to the substrate support to attract ions from the plasma to the substrate on the substrate support. Such a plasma processing device is described in the following patent document 1.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2000-173993 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] The present disclosure provides a technique for improving the etching rate and the verticality of an opening formed in a substrate.

[0008] Solutions for solving problems

[0009] In an exemplary embodiment, a plasma processing device is provided. The plasma processing device includes a chamber, a substrate support, a high-frequency power supply, a bias power supply, and a control unit. The substrate support is disposed in the chamber. The high-frequency power supply is configured to supply source high-frequency power to generate plasma in the chamber. The bias power supply is electrically coupled to the substrate support. The control unit is configured to control the high-frequency power supply and the bias power supply. The control unit causes a cycle to be repeated. The cycle includes the following steps: step (i), supplying a pulse of source high-frequency power from the high-frequency power supply to generate plasma from a gas in the chamber; and step (ii), supplying a pulse of electrical bias from the bias power supply to the substrate support. The pulse of electrical bias includes a DC voltage pulse periodically generated at a bias frequency of less than 1 MHz. The pulse frequency as the repetition frequency of the cycle is greater than 5 kHz. The control unit sets the start timing of the pulse of electrical bias in step (ii) in the cycle to a timing later than the start timing of the pulse of source high-frequency power in step (i) and at the same time as or earlier than the stop timing of the pulse of source high-frequency power in step (i). The control unit sets the timing of stopping the pulse of the electrical bias in step (ii) to a timing later than the timing of stopping the pulse of the source high-frequency power within the cycle.

[0010] Effects of the Invention

[0011] According to an exemplary embodiment, an etching rate and verticality of an opening formed in a substrate can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a diagram for explaining a configuration example of a plasma processing system.

[0013] Figure 2 It is a diagram for explaining a configuration example of a capacitive coupling type plasma processing apparatus.

[0014] Figure 3 is a flow chart of a plasma processing method according to an exemplary embodiment.

[0015] Figure 4 It is shown Figure 4 A diagram showing a detailed example of step STc of the plasma processing method shown.

[0016] Figure 5 (a)~ Figure 5 The (d) are respectively Figure 3 A partially enlarged cross-sectional view of a substrate showing an example of each step in the plasma processing method shown.

[0017] Figure 6 is a timing chart associated with a plasma processing method according to an exemplary embodiment.

[0018] Figure 7 (a) and Figure 7 (b) are timing charts associated with a plasma processing method according to an exemplary embodiment.

[0019] Figure 8 is a timing chart associated with a plasma processing method according to an exemplary embodiment. DETAILED DESCRIPTION

[0020] Hereinafter, various exemplary embodiments will be described in detail with reference to the accompanying drawings. In addition, in each of the drawings, the same reference numerals are given to the same or corresponding parts.

[0021] Figure 1: is a diagram for illustrating a structural example of a plasma processing system. In one embodiment, the plasma processing system includes a plasma processing device 1 and a control unit 2. The plasma processing system is an example of a substrate processing system, and the plasma processing device 1 is an example of a substrate processing device. The plasma processing device 1 includes a plasma processing chamber 10, a substrate support portion 11, and a plasma generating portion 12. The plasma processing chamber 10 has a plasma processing space. In addition, the plasma processing chamber 10 has at least one gas supply port for supplying at least one processing gas to the plasma processing space, and at least one gas exhaust port for exhausting gas from the plasma processing space. The gas supply port is connected to the gas supply portion 20 described later, and the gas exhaust port is connected to the exhaust system 40 described later. The substrate support portion 11 is arranged in the plasma processing space and has a substrate supporting surface for supporting a substrate.

[0022] The plasma generating unit 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma formed in the plasma processing space may be 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), etc.

[0023] The control unit 2 processes computer executable commands that cause the plasma processing device 1 to perform various processes described in the present disclosure. The control unit 2 can be configured to control the various elements of the plasma processing device 1 to perform various processes described herein. In one embodiment, a part or all of the control unit 2 may also be included in the plasma processing device 1. The control unit 2 may include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The control unit 2 is implemented, for example, by a computer 2a. The processing unit 2a1 can be configured to perform various control actions by reading a program from the storage unit 2a2 and executing the read program. The program can be stored in the storage unit 2a2 in advance, 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 by the computer 2a, or it can be a communication line connected to the communication interface 2a3. The processing unit 2a1 can be a CPU (Central Processing Unit). The storage unit 2a2 may 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 communicate with the plasma processing apparatus 1 via a communication line such as a LAN (Local Area Network).

[0024] Next, a configuration example of a capacitive coupling type plasma processing apparatus will be described as an example of the plasma processing apparatus 1 . Figure 2 It is a diagram for explaining a configuration example of a capacitive coupling type plasma processing apparatus.

[0025] A 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. In addition, the plasma processing apparatus 1 includes a substrate support unit 11 and a gas inlet unit. The gas inlet unit is configured to introduce at least one processing gas into the plasma processing chamber 10. The gas inlet unit includes a shower head 13. The substrate support unit 11 is disposed in the plasma processing chamber 10. The shower head 13 is disposed above the substrate support unit 11. In one embodiment, the shower head 13 constitutes at least a portion of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the shower head 13, the side wall 10a of the plasma processing chamber 10, and the substrate support unit 11. The plasma processing chamber 10 is grounded. The substrate support unit 11 is electrically insulated from the shell of the plasma processing chamber 10.

[0026] 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. The annular area 111b of the main body 111 surrounds the central area 111a of the main body 111 when viewed from above. 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.

[0027] In one embodiment, the main body 111 includes a base 1110 and an electrostatic holding disk 1111. The base 1110 includes a conductive component. The electrostatic holding disk 1111 is arranged on the base 1110. The electrostatic holding disk 1111 includes a ceramic component 1111a and an electrostatic electrode 1111b arranged in the ceramic component 1111a. The ceramic component 1111a has a central area 111a. In one embodiment, the ceramic component 1111a also has an annular area 111b. In addition, other components surrounding the electrostatic holding disk 1111, such as an annular electrostatic holding disk and an annular insulating component, may also have an annular area 111b. In this case, the ring assembly 112 may also be arranged on the annular electrostatic holding disk or the annular insulating component, and may also be arranged on both the electrostatic holding disk 1111 and the annular insulating component.

[0028] The ring assembly 112 includes one or more ring-shaped members. In one embodiment, the one or more ring-shaped members include one or more edge rings and at least one cover ring. The edge ring is formed of a conductive material or an insulating material, and the cover ring is formed of an insulating material.

[0029] In addition, the substrate support 11 may also include a temperature control module, which is configured to adjust at least one of the electrostatic holding disk 1111, the ring assembly 112 and the substrate to a target temperature. The temperature control module may include a heater, a heat transfer medium, a flow path 1110a or a combination thereof. A heat transfer fluid such as brine or gas flows in the flow path 1110a. In one embodiment, the flow path 1110a is formed in the base 1110, and one or more heaters are arranged in the ceramic component 1111a of the electrostatic holding disk 1111. In addition, the substrate support 11 may also include a heat transfer gas supply unit, which is configured to supply a heat transfer gas to the gap between the back side of the substrate W and the central area 111a.

[0030] The shower head 13 is configured to introduce at least one processing gas from the gas supply unit 20 into the plasma processing space 10s. The shower head 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and 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, the gas introduction unit may also include one or more side gas injection units (SGI: Side Gas Injector) in addition to the shower head 13, and the one or more side gas injection units are installed in one or more openings formed in the side wall 10a.

[0031] The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one process gas from the respective gas sources 21 to the shower head 13 via the respective flow controllers 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 also include at least one flow modulation device for modulating or pulsing the flow of at least one process gas.

[0032] The exhaust system 40 can be connected to a gas outlet 10e, for example, provided at the bottom of the plasma processing chamber 10. The exhaust system 40 can include a pressure regulating valve and a vacuum pump. The pressure in the plasma processing space 10s is adjusted by the pressure regulating valve. The vacuum pump can include a turbomolecular pump, a dry pump, or a combination thereof.

[0033] 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 HF. The source high-frequency power HF has a source frequency. That is, the source high-frequency power HF has a sinusoidal waveform whose frequency is the source frequency. The source frequency can be a frequency in the range of 10 MHz to 150 MHz. The high-frequency power supply 31 is electrically connected to the high-frequency electrode via a matcher 33, and is configured to supply the source high-frequency power HF to the high-frequency electrode. The high-frequency electrode can be arranged in the substrate support portion 11. The high-frequency electrode can be a conductive component of the base 1110 or at least one electrode arranged in the ceramic component 1111a. Alternatively, the high-frequency electrode can also be an upper electrode. When the source high-frequency power HF is supplied to the high-frequency electrode, plasma is generated from the gas in the chamber 10.

[0034] The matching device 33 has a variable impedance. The variable impedance of the matching device 33 is set to reduce reflection of the source high frequency power HF from the load. The matching device 33 can be controlled by the control unit 2, for example.

[0035] The bias power supply 32 is electrically coupled to the substrate support 11. The bias power supply 32 is electrically connected to the bias electrode in the substrate support 11, and is configured to supply an electric bias EB to the bias electrode. The bias electrode may be a conductive member of the base 1110 or at least one electrode provided in the ceramic member 1111a. The bias electrode may also be an electrode common to 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.

[0036] Electrical bias EB and its pulse EBP (refer to Figure 6 ) includes a DC voltage pulse PV generated periodically at a bias frequency of less than 1 MHz (refer to Figure 7 ). That is, the electric bias EB and its pulse EBP are composed of a DC voltage pulse PV periodically generated at a time interval (waveform period CY) that is the inverse of the bias frequency. The bias frequency can be 400kHz or less. In addition, in the following, the level of the electric bias EB is sometimes described. The level of the electric bias EB is the absolute value of the negative voltage level of the DC voltage pulse PV. In addition, the level of the electric bias EB being zero means that the supply of the electric bias EB to the bias electrode is stopped.

[0037] Next, Figure 3 to Figure 7 and Figure 1 and Figure 2 Referring to the plasma processing method according to an exemplary embodiment, the control of each part of the plasma processing device 1 by the control unit 2 is also described. Figure 6 , Figure 7 (a) and Figure 7 (b) shows a timing diagram of the active high frequency power HF and the electric bias EB.

[0038] Figure 3 The plasma processing method shown (hereinafter referred to as "method MT") can be performed using the plasma processing device 1. The method MT includes a step STc. The method MT may also include a step STp, a step STa, and a step STb. The method MT may also include a step STd. The steps STa, STb, STc, and STd can be brought about by controlling the various parts of the plasma processing device 1 by the control unit 2.

[0039] In step STp, a substrate W is prepared on the substrate support 11 in the chamber 10. The substrate W is placed on the substrate support 11 and held by the electrostatic holding disk 1111. As an example, the substrate W is Figure 5As shown in (a), the substrate W includes a film EF (Etch Film: etching film) and a mask MK. The film EF is a dielectric film. The film EF is formed of, for example, silicon oxide. The mask MK is disposed on the film EF. The mask MK is formed of a material selected so that the film EF is selectively etched relative to the mask MK in the step STc. The mask MK is formed of, for example, an organic material. The substrate W may also have a base region UR. The film EF is disposed on the base region UR.

[0040] In step STa, if Figure 5 As shown in (b), a deposit DP is formed on the substrate W on the substrate support 11. Therefore, in step STa, the processing gas is supplied into the chamber 10, and the source high frequency power HF is supplied to the high frequency electrode while the supply of the electric bias EB to the bias electrode is stopped.

[0041] The processing gas used in step STa has deposition properties. The processing gas used in step STa may include a gas component containing fluorine and carbon. The gas component may be a fluorocarbon gas such as C4F8 gas. The gas component may also include a hydrofluorocarbon gas as a supplement or substitute for the fluorocarbon gas. The processing gas may also include one or more of nitrogen, an oxygen-containing gas (such as oxygen), and a noble gas (such as Ar gas).

[0042] In step STa, the control unit 2 controls the gas supply unit 20 to supply the processing gas into the chamber 10. In step STa, the control unit 2 controls the exhaust system 40 to adjust the pressure in the chamber 10 to a specified pressure. In step STa, the control unit 2 controls the bias power supply 32 to stop supplying the electric bias EB to the bias electrode, and the control unit 2 controls the high-frequency power supply 31 to supply the source high-frequency power HF to the high-frequency electrode. Figure 6 As shown, the control unit 2 sets the power level of the source high frequency power HF in the step STa to the power level L HFa .

[0043] like Figure 3 and Figure 6 As shown in FIG. 1 , step STb is performed after step Sta. In step STb, ions from plasma generated from the processing gas in the chamber 10 are supplied to the deposit DP. Figure 5 As shown in (c), a deposit MDP modified from the deposit DP is formed. Therefore, in step STb, a source high frequency power HF is supplied to the high frequency electrode, and an electric bias EB is supplied to the bias electrode. Figure 6 As shown, the power level of the source high frequency power HF in step STb is increased from the power level L of the source high frequency power HF in step STa. HFa Change and set to power level L HFb . Power level LHFb Can be compared to the power level L HFa Small.

[0044] The processing gas used to generate plasma in step STb can be the same as the above-mentioned processing gas used in step STa. In step STb, the control unit 2 controls the gas supply unit 20 to supply the processing gas into the chamber 10. In step STb, the control unit 2 controls the exhaust system 40 to adjust the pressure in the chamber 10 to a specified pressure. In step STb, the control unit 2 controls the bias power supply 32 to supply an electrical bias EB to the bias electrode. In step STb, the control unit 2 controls the high-frequency power supply 31 to supply a source high-frequency power HF to the high-frequency electrode. Figure 6 As shown, the control unit 2 sets the power level of the source high frequency power HF in step STb to the power level L HFb The control unit 2 sets the level of the electric bias EB in step STb to level L EBb .

[0045] like Figure 3 and Figure 6 As shown, step STc is performed after step STb. In step STc, cycle CA is repeated to etch film EF. Figure 4 As shown, cycle CA includes step STc1 and step STc2.

[0046] In step STc1, source high frequency power HF is supplied from the high frequency power source 31 to the high frequency electrode to generate plasma from the etching gas in the chamber 10. The etching gas may be the same processing gas as the processing gas used in step STa and / or step STb. Alternatively, the etching gas may be another gas selected in such a manner that the film EF is selectively etched. Figure 6 As shown, the power level of the pulse HFP of the source high frequency power HF in step STc1 is set to the power level L HFc . Power level L HFc Can be compared to the power level L HFa Smaller than the power level L HFb big.

[0047] In step STc2, a pulse of an electric bias EB is supplied from the bias power supply 32 to the bias electrode to attract ions from the plasma generated from the etching gas to the substrate W. Figure 6 As shown, the level of the pulse EBP of the electric bias EB in step STc2 is set to level L EBc Level L EBc Can be compared to level L EBbThat is, the absolute value of the negative voltage level of the DC voltage pulse PV in step STc2 may be greater than the absolute value of the negative voltage level of the DC voltage pulse PV in step STb. The absolute value of the negative voltage level of the DC voltage pulse PV in step STc2 may be greater than 100V or greater than 1000V.

[0048] In the next step STJA, it is determined whether the stop condition is satisfied. The stop condition is satisfied when the number of times of loop CA reaches a predetermined number. If it is determined in step STJA that the stop condition is not satisfied, loop CA is performed again. If it is determined in step STJA that the stop condition is satisfied, step STc ends.

[0049] The pulse frequency, which is the repetition frequency of the cycle CA, that is, the inverse of the time length of the cycle CA is 5 kHz or more. The pulse frequency may be 10 kHz or more or 20 kHz or more.

[0050] In step STc1 and step STc2, the control unit 2 controls the gas supply unit 20 to supply etching gas into the chamber 10. In each of step STc1 and step STc2, the control unit 2 controls the exhaust system 40 to adjust the pressure in the chamber 10 to a specified pressure. In step STc1, the control unit 2 controls the high-frequency power source 31 to supply pulse HFP of source high-frequency power HF to the high-frequency electrode. The control unit 2 sets the power level of the pulse HFP in step STc1 to the power level L. HFc In addition, the supply of the source high frequency power HF can be stopped during the period other than the period of step STc1 in the cycle CA. In step STc2, the control unit 2 controls the bias power supply 32 to supply the pulse EBP of the electrical bias EB to the bias electrode. The control unit 2 sets the level of the pulse EBP in step STc2 to level L. EBc In addition, the supply of the electric bias EB can be stopped during the period other than the period of step STc2 in the cycle CA.

[0051] like Figure 7 (a) and Figure 7 As shown in (b), the control unit 2 sets the start timing t of the pulse EBP in the step STc2 in the cycle CA to EBPS The start timing t of the pulse HFP in the step STc1 in the cycle CA is set to HFPS Late timing. Figure 7 As shown in (a), the control unit 2 sets the start timing t of the pulse EBP in the step STc2 in the cycle CA to EBPS The timing t of stopping the pulse HFP in step STc1 in the cycle CA is set to HFPE Same timing. Or, Figure 7As shown in (b), the control unit 2 sets the start timing t of the pulse EBP in the step STc2 in the cycle CA to EBPS The stop timing t of the pulse HFP in the step STc1 in the cycle CA is set to HFPE In addition, the control unit 2 sets the stop timing of the pulse EBP in the step STc2 in the cycle CA to EBPE The stop timing t of the pulse HFP in the step STc1 in the cycle CA is set to HFPE Late timing.

[0052] like Figure 3 and Figure 6 As shown, step STd is performed after step STc. In step STd, the etching byproducts generated in step STc are discharged from the chamber 10. In step STd, the control unit 2 controls the exhaust system 40 to exhaust the chamber 10. In step STd, the control unit 2 controls the high-frequency power supply 31 to stop the supply of the source high-frequency power HF. In step STd, the control unit 2 controls the bias power supply 32 to stop the supply of the electric bias EB.

[0053] In one embodiment, if Figure 3 As shown, method MT may also include repetition of loop CB, which includes step STa, step STb, and step STc. Loop CB may also include step STd. In this case, in step STJB, it is determined whether the stop condition is satisfied. The stop condition is satisfied when the number of times loop CB is performed reaches a predetermined number of times. If it is determined that the stop condition is not satisfied in step STJB, loop CB is performed again. If it is determined that the stop condition is satisfied in step STJB, method MT ends.

[0054] In method MT, film EF is etched by etching in step STc, such as Figure 5 As shown in (d), the pattern of the mask MK is transferred to the film EF.

[0055] As described above, the start timing t of the pulse EBP of the electric bias EB in the cycle CA is EBPS The timing t at which the pulse HFP of the source high frequency power HF in the cycle CA stops HFPE At the same time or than the stop time t HFPE In addition, the repetition frequency of the cycle CA, that is, the pulse frequency, is 5 kHz or more. Therefore, the ions of the plasma generated in the step STc1 can be supplied to the substrate W in the step STc2 without deactivating the ions. Therefore, according to the method MT, the etching rate of the film EF is increased.

[0056] In addition, in the method MT, a DC voltage pulse PV periodically generated at a bias frequency of 1 MHz or less is used as a pulse EBP of the electric bias EB. Therefore, in the step STc2, the dissociation of the etching gas is suppressed by the electric bias EB, and the excessive formation of deposits on the substrate W is suppressed. In addition, in the step STc2, monochromatized ions with high energy are supplied to the substrate W. Therefore, a concave portion with high verticality is formed in the film EF by etching in the step STc.

[0057] In addition, in step STb, ions with relatively high energy are supplied to the deposit DP to remove unnecessary elements (e.g., fluorine) from the deposit DP. Therefore, in the deposit MDP obtained by step STb, bonds with high bond energy (e.g., carbon-carbon bonds) can be formed more. The mask MK is protected from the etching of step STc by the deposit MDP modified in this way. Therefore, according to method MT, the reduction of the mask MK caused by etching can be suppressed.

[0058] Below, refer to Figure 8 .exist Figure 8 , a timing diagram of the electric bias EB and the source frequency of the source high frequency power HF is shown. In a part of the process STc1 and in the process STb, the source high frequency power HF and the electric bias EB are supplied simultaneously. In the repeated period in which the source high frequency power HF and the electric bias EB are supplied simultaneously, the source frequency of the source high frequency power HF may be changed to suppress the degree of reflection of the source high frequency power HF from the load. Specifically, in the waveform period CY of the DC voltage pulse PV in the repeated period, Figure 8 Change the source frequency as shown.

[0059] like Figure 8 As shown, the waveform period CY may be divided into a plurality of phase periods SP. The source frequency is set to reduce the degree of reflection of the source high frequency power HF in each phase period SP in the waveform period CY in the repetition period. The source frequency for each of the plurality of phase periods SP in the waveform period CY in the repetition period may be assigned to the high frequency power source 31 by the control unit 2.

[0060] The source frequency of each phase period SP in the multiple phase periods SP in the waveform period CY within the repetition period can also be set using a pre-prepared frequency group including multiple frequencies for each phase period SP in the multiple phase periods SP. Alternatively, the following source frequency can be used in the subsequent phase period SP(n): the source frequency is determined in a manner that minimizes the degree of reflection of the source high-frequency power HF obtained by using different source frequencies of the same phase period SP(n) in the preceding two or more waveform periods CY. In addition, the phase period SP(n) represents the nth phase period among the multiple phase periods SP in the waveform period CY.

[0061] Plasma processing device 1 Figure 2 As shown, a sensor 35 and / or a sensor 36 may be further provided to determine the degree of reflection of the source high frequency power HF. The sensor 35 is configured to measure the power level Pr of the reflected wave emitted from the source high frequency power HF by the load. The sensor 35 includes, for example, a directional coupler. The directional coupler may be provided between the high frequency power source 31 and the matching device 33. In addition, the sensor 35 may also be configured to measure the power level Pf of the traveling wave of the source high frequency power HF. The power level Pr of the reflected wave measured by the sensor 35 is notified to the control unit 2. In addition, the power level Pf of the traveling wave may also be notified from the sensor 35 to the control unit 2.

[0062] The sensor 36 includes a voltage sensor and a current sensor. The sensor 36 is configured to measure a voltage V in a power supply circuit connecting the high-frequency power source 31 and the high-frequency electrode to each other. RF and current I RF The source high frequency power HF is supplied to the high frequency electrode through the power supply circuit. The sensor 36 can be arranged between the high frequency power supply 31 and the matching device 33. The voltage V RF and current I RF Notify the control unit 2.

[0063] The control unit 2 generates a representative value based on the measured value during each phase period SP in the plurality of phase periods SP. The measured value may be the power level Pr of the reflected wave acquired by the sensor 35. The measured value may also be the value of the ratio of the power level Pr of the reflected wave of the source high frequency power HF to the output power level (i.e., reflectivity). The measured value may also be the voltage V p obtained by the sensor 36 during each phase period SP in the plurality of phase periods SP. RF With current I RF The measured value may also be the impedance Z of the load side of the high frequency power supply 31 during each phase period SP of the plurality of phase periods SP. The impedance Z is determined based on the voltage V obtained by the sensor 36. RF and current I RFThe representative value may be an average value or a maximum value of the measured value in each phase period SP in the plurality of phase periods SP. The control unit 2 can use the representative value in each phase period SP in the plurality of phase periods SP as a value representing the degree of reflection of the source high frequency power HF to determine the source frequency. In addition, the degree of reflection and the source frequency may also be determined by the high frequency power source 31.

[0064] 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. In addition, elements in different embodiments may be combined to form other embodiments.

[0065] Here, various exemplary embodiments included in the present disclosure are described in the following [E1] to [E13].

[0066] [E1] A plasma processing device comprising:

[0067] Chamber;

[0068] a substrate support portion, which is disposed in the chamber;

[0069] a high frequency power supply configured to supply high frequency power to generate plasma in the chamber;

[0070] a bias power supply electrically coupled to the substrate support; and

[0071] a control unit configured to control the high frequency power supply and the bias power supply,

[0072] The control unit is configured to cause a repetition of a cycle including the following steps:

[0073] Step (i), supplying a pulse of the source high frequency power from the high frequency power supply to generate plasma from a gas in the chamber; and

[0074] step (ii), supplying an electrical bias pulse from the bias power supply to the substrate support portion,

[0075] The electrical bias pulses include DC voltage pulses periodically generated at a bias frequency of less than 1 MHz,

[0076] The pulse frequency as the repetition frequency of the cycle is 5 kHz or more,

[0077] The control unit is configured to perform the following settings within the cycle:

[0078] The start timing of the pulse of the electrical bias in the step (ii) is set to a timing later than the start timing of the pulse of the source high-frequency power in the step (i) and to be simultaneous with or earlier than the stop timing of the pulse of the source high-frequency power in the step (i),

[0079] The timing of stopping the pulse of the electrical bias in the step (ii) is set to be later than the timing of stopping the pulse of the source high-frequency power.

[0080] [E2] A plasma processing apparatus according to [E1], wherein:

[0081] The control unit is configured to further include the following steps:

[0082] Step (a), supplying a deposition-capable processing gas into the chamber and supplying the source high-frequency power from the high-frequency power supply while stopping the supply of the electrical bias, so as to form a deposit on the substrate on the substrate support; and

[0083] step (b), changing the power level of the source high frequency power from the power level in the step (a) and supplying the electric bias to modify the deposit by supplying ions from the plasma to the deposit,

[0084] The control unit is configured to cause the repetition of the cycle after the step (a) and the step (b).

[0085] [E3] A plasma processing apparatus according to [E2], wherein:

[0086] The control unit is further configured to cause repetition of another cycle including the step (a), the step (b), and repetition of the cycle including the step (i) and the step (ii).

[0087] [E4] A plasma processing apparatus according to [E3], wherein:

[0088] The control unit is configured to further provide a step of exhausting the chamber in a state where the source high frequency power and the electrical bias are stopped after the cycle including the step (i) and the step (ii) in the other cycle.

[0089] [E5] A plasma processing apparatus according to any one of [E2] to [E4], wherein:

[0090] The control unit is configured to set the power level of the source high-frequency power in the step (b) to a level lower than the power level in the step (a).

[0091] [E6] A plasma processing apparatus according to any one of [E2] to [E5], wherein:

[0092] The control unit is configured to make the absolute value of the negative voltage level of the DC voltage pulse in the step (ii) larger than the absolute value of the negative voltage level of the DC voltage pulse in the step (b).

[0093] [E7] A plasma processing apparatus according to any one of [E1] to [E6], wherein:

[0094] The control unit is configured to change the source frequency of the source high-frequency power within the waveform period of the DC voltage pulse while simultaneously supplying the source high-frequency power in the step (i) and supplying the electrical bias in the step (ii) to suppress the degree of reflection of the source high-frequency power from the load.

[0095] [E8] A plasma processing apparatus according to any one of [E1] to [E7], wherein:

[0096] The DC voltage pulse is a negative DC voltage pulse, and in the step (ii), the DC voltage pulse has an absolute value of 100 V or more.

[0097] [E9] A plasma processing apparatus according to any one of [E1] to [E8], wherein:

[0098] The pulse frequency is above 10 kHz.

[0099] [E10] The plasma processing apparatus according to any one of [E1] to [E9], wherein:

[0100] The bias frequency is below 400 kHz.

[0101] [E11] A plasma treatment method comprising the following steps:

[0102] preparing a substrate including a film and a mask disposed on the film on a substrate support in a chamber of a plasma processing apparatus; and

[0103] The cycle is repeated to etch the film,

[0104] The cycle includes the following steps:

[0105] Step (i), supplying a pulse of high frequency power from a high frequency power source to generate plasma from a gas in the chamber; and

[0106] step (ii), supplying an electrical bias pulse from a bias power supply to the substrate support portion,

[0107] The electrical bias pulses include DC voltage pulses periodically generated at a bias frequency of less than 1 MHz,

[0108] The pulse frequency as the repetition frequency of the cycle is 5 kHz or more,

[0109] Within the loop,

[0110] The start timing of the pulse of the electrical bias in the step (ii) is later than the start timing of the pulse of the source high-frequency power in the step (i) and is simultaneous with or earlier than the stop timing of the pulse of the source high-frequency power in the step (i),

[0111] The timing of stopping the pulse of the electrical bias in the step (ii) is later than the timing of stopping the pulse of the source high-frequency power.

[0112] [E12] The plasma treatment method according to [E11], further comprising the following steps:

[0113] Step (a), supplying a deposition-capable processing gas into the chamber and supplying the source high-frequency power from the high-frequency power supply while stopping the supply of the electrical bias, so as to form a deposit on the substrate on the substrate support; and

[0114] step (b), changing the power level of the source high frequency power from the power level in the step (a) and supplying the electric bias to modify the deposit by supplying ions from the plasma to the deposit,

[0115] The repetition of the cycle is performed after the step (a) and the step (b).

[0116] [E13] A plasma processing device comprising:

[0117] Chamber;

[0118] a substrate support portion, which is disposed in the chamber;

[0119] a high frequency power supply configured to supply high frequency power to generate plasma in the chamber;

[0120] a bias power supply electrically coupled to the substrate support; and

[0121] a control unit configured to control the high frequency power supply and the bias power supply,

[0122] The control unit is configured to bring about the following steps:

[0123] Step (a), supplying a deposition-capable processing gas into the chamber and supplying the source high-frequency power from the high-frequency power supply while stopping the supply of an electrical bias from the bias power supply to the substrate support portion; and

[0124] step (b), changing the power level of the source high frequency power from the power level in the step (a) and supplying the electrical bias,

[0125] The control unit is configured to repeat a cycle including the following steps after the steps (a) and (b):

[0126] Step (i), supplying a pulse of the source high frequency power from the high frequency power source; and

[0127] In step (ii), the bias power supply supplies the electric bias pulse to the substrate support portion, wherein the control portion is configured to perform the following settings within the cycle:

[0128] The start timing of the pulse of the electrical bias in the step (ii) is set to a timing later than the start timing of the pulse of the source high-frequency power in the step (i) and to be simultaneous with or earlier than the stop timing of the pulse of the source high-frequency power in the step (i),

[0129] The timing of stopping the pulse of the electrical bias in the step (ii) is set to be later than the timing of stopping the pulse of the source high-frequency power.

[0130] According to the above description, it should be understood that the various embodiments of the present disclosure are described in this specification for the purpose of explanation, and various changes can be made to the various embodiments of the present disclosure without departing from the scope and spirit of the present disclosure. Therefore, the various embodiments disclosed in this specification are not intended to be limiting, and the true scope and spirit are shown by the attached claims.

[0131] Description of Reference Numerals

[0132] 1: plasma processing device; 2: control unit; 10: chamber; 11: substrate support unit; 31: high-frequency power supply; 32: bias power supply; HF: source high-frequency power; EB: electrical bias.

Claims

1. A plasma processing device, comprising: Chamber; a substrate support portion, which is disposed in the chamber; a high frequency power supply configured to supply high frequency power to generate plasma in the chamber; a bias power supply electrically coupled to the substrate support; as well as a control unit configured to control the high frequency power supply and the bias power supply, The control unit is configured to cause a repetition of a cycle including the following steps: Step (i), supplying a pulse of the source high frequency power from the high frequency power source to generate plasma from the gas in the chamber; as well as Step (ii), supplying an electrical bias pulse from the bias power supply to the substrate support portion, wherein the electrical bias pulse includes a DC voltage pulse periodically generated at a bias frequency of 1 MHz or less, The pulse frequency as the repetition frequency of the cycle is 5 kHz or more, The control unit is configured to perform the following settings within the cycle: The start timing of the pulse of the electrical bias in the step (ii) is set to a timing later than the start timing of the pulse of the source high-frequency power in the step (i) and to be simultaneous with or earlier than the stop timing of the pulse of the source high-frequency power in the step (i), The timing of stopping the pulse of the electrical bias in the step (ii) is set to be later than the timing of stopping the pulse of the source high-frequency power.

2. The plasma processing apparatus according to claim 1, wherein: The control unit is configured to further include the following steps: Step (a), supplying a deposition-capable processing gas into the chamber and supplying the source high-frequency power from the high-frequency power supply while stopping the supply of the electrical bias, so as to form a deposit on the substrate on the substrate support; as well as step (b), changing the power level of the source high frequency power from the power level in the step (a) and supplying the electric bias to modify the deposit by supplying ions from the plasma to the deposit, The control unit is configured to cause the repetition of the cycle after the step (a) and the step (b).

3. The plasma processing apparatus according to claim 2, wherein: The control unit is further configured to cause repetition of another cycle including the step (a), the step (b), and repetition of the cycle including the step (i) and the step (ii).

4. The plasma processing apparatus according to claim 3, wherein: The control unit is configured to further provide a step of exhausting the chamber in a state where the source high frequency power and the electrical bias are stopped after the cycle including the step (i) and the step (ii) in the other cycle.

5. The plasma processing apparatus according to any one of claims 2 to 4, wherein: The control unit is configured to set the power level of the source high-frequency power in the step (b) to a level lower than the power level in the step (a).

6. The plasma processing apparatus according to any one of claims 2 to 4, wherein: The control unit is configured to make the absolute value of the negative voltage level of the DC voltage pulse in the step (ii) larger than the absolute value of the negative voltage level of the DC voltage pulse in the step (b).

7. The plasma processing apparatus according to any one of claims 1 to 4, wherein: The control unit is configured to change the source frequency of the source high-frequency power within the waveform period of the DC voltage pulse while simultaneously supplying the source high-frequency power in the step (i) and supplying the electrical bias in the step (ii) to suppress the degree of reflection of the source high-frequency power from the load.

8. The plasma processing apparatus according to any one of claims 1 to 4, wherein: The DC voltage pulse is a negative DC voltage pulse, and in the step (ii), the DC voltage pulse has an absolute value of 100 V or more.

9. The plasma processing apparatus according to any one of claims 1 to 4, wherein: The pulse frequency is above 10 kHz.

10. The plasma processing apparatus according to any one of claims 1 to 4, wherein: The bias frequency is below 400 kHz.

11. A plasma treatment method comprising the following steps: 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; as well as The cycle is repeated to etch the film, The cycle includes the following steps: Step (i), supplying a pulse of high frequency power from a high frequency power source to generate plasma from the gas in the chamber; as well as step (ii), supplying an electrical bias pulse from a bias power supply to the substrate support portion, The electrical bias pulses include DC voltage pulses periodically generated at a bias frequency of less than 1 MHz, The pulse frequency as the repetition frequency of the cycle is 5 kHz or more, Within the loop, The start timing of the pulse of the electrical bias in the step (ii) is later than the start timing of the pulse of the source high-frequency power in the step (i) and is simultaneous with or earlier than the stop timing of the pulse of the source high-frequency power in the step (i), The timing of stopping the pulse of the electrical bias in the step (ii) is later than the timing of stopping the pulse of the source high-frequency power.

12. The plasma processing method according to claim 11, further comprising the following steps: Step (a), supplying a deposition-capable processing gas into the chamber and supplying the source high-frequency power from the high-frequency power supply while stopping the supply of the electrical bias, so as to form a deposit on the substrate on the substrate support; and step (b), changing the power level of the source high frequency power from the power level in the step (a) and supplying the electric bias to modify the deposit by supplying ions from the plasma to the deposit, The repetition of the cycle is performed after the step (a) and the step (b).

13. A plasma processing device comprising: Chamber; a substrate support portion, which is disposed in the chamber; a high frequency power supply configured to supply high frequency power to generate plasma in the chamber; a bias power supply electrically coupled to the substrate support; as well as a control unit configured to control the high frequency power supply and the bias power supply, The control unit is configured to bring about the following steps: Step (a), supplying a deposition-capable processing gas into the chamber and supplying the source high-frequency power from the high-frequency power supply while stopping the supply of an electrical bias from the bias power supply to the substrate support portion; as well as step (b), changing the power level of the source high frequency power from the power level in the step (a) and supplying the electrical bias, The control unit is configured to repeat a cycle including the following steps after the steps (a) and (b): Step (i), supplying a pulse of the source high frequency power from the high frequency power source; as well as In step (ii), the bias power supply supplies the electric bias pulse to the substrate support portion, wherein the control portion is configured to perform the following settings within the cycle: The start timing of the pulse of the electrical bias in the step (ii) is set to a timing later than the start timing of the pulse of the source high-frequency power in the step (i) and to be simultaneous with or earlier than the stop timing of the pulse of the source high-frequency power in the step (i), The timing of stopping the pulse of the electrical bias in the step (ii) is set to be later than the timing of stopping the pulse of the source high-frequency power.

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