Plasma processing apparatus and plasma processing method

Abstract

The plasma processing apparatus includes a chamber, a substrate support portion, a high-frequency power source, a bias power source, and a control portion. The control unit can control the high-frequency power supply and the bias power supply. The control unit is capable of performing control so as to execute: a step (a) in which a source high-frequency electric power is supplied to generate plasma in the chamber; and (b) supplying an electrical bias to the substrate support unit. The control unit is capable of setting a delay time length from a point in time at which the source high-frequency electric power is started to a point in time at which the electric bias is started to be supplied in step (a) to a point in time at which the electric bias is started to be supplied in step (b). The length of time for electrons to reach from the center of the substrate support part or the center of the substrate on the substrate support part to the end part of the substrate support part or the end part of the substrate is set to be greater than or equal to the length of time.

Description

Technical Field

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

[0002] A plasma processing device is used for plasma processing of a substrate. In the plasma processing device, bias high-frequency electric power is used to attract ions from plasma generated in a chamber to the substrate. Patent document 1 below discloses a plasma processing device capable of modulating the power level and frequency of the bias high-frequency electric power.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2009-246091 Summary of the invention

[0006] Technical problem to be solved by the invention

[0007] The present invention provides a technology capable of improving the uniformity of plasma density distribution.

[0008] Means for solving technical 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 arranged in the chamber. The high-frequency power supply can generate source high-frequency electric power. The bias power supply is electrically coupled to the substrate support and can generate an electric bias for attracting ions to the substrate support. The control unit can control the high-frequency power supply and the bias power supply. The control unit can control so that: step (a), supplying source high-frequency electric power to generate plasma in the chamber; and step (b), supplying an electric bias to the substrate support during the supply of the source high-frequency electric power. The control unit can set the delay time length from the time point when the source high-frequency electric power is started in step (a) to the time point when the electric bias is started in step (b) to be longer than the reference time length. The reference time length is the time length for electrons to reach the end of the substrate support or the end of the substrate from the center of the substrate support or the center of the substrate on the substrate support.

[0010] Effects of the Invention

[0011] According to an exemplary embodiment, uniformity of density distribution of plasma 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 This is a diagram for explaining a configuration example of a capacitive coupling type plasma processing apparatus.

[0014] Figure 3 (a) and Figure 3 (b) are each a timing diagram related to a plasma processing apparatus according to an exemplary embodiment.

[0015] Figure 4 (a) and Figure 4 (b) are each a timing diagram related to a plasma processing apparatus according to an exemplary embodiment.

[0016] Figure 5 is a flow chart of a plasma processing method according to an exemplary embodiment. DETAILED DESCRIPTION

[0017] 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.

[0018] 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.

[0019] The plasma generating unit 12 can generate plasma from at least one processing gas supplied into the plasma processing space. The plasma formed in the plasma processing space can 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.

[0020] The control unit 2 is capable of processing computer-executable commands, which are used to cause the plasma processing device 1 to perform various processes described in the present invention. The control unit 2 is capable of controlling the various elements of the plasma processing device 1 to perform the various processes described herein. In one embodiment, part or all of the control unit 2 may 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 is capable of reading a program from the storage unit 2a2 and performing various control actions by executing the read program. The program may be pre-stored in the storage unit 2a2 or acquired via a medium when necessary. The acquired 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 may be various storage media readable by the computer 2a, or a communication line connected to the communication interface 2a3. The processing unit 2a1 may be a CPU (Central Processing Unit). The storage unit 2a2 may include a 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 device 1 via a communication line such as a LAN (Local Area Network).

[0021] 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 This is a diagram for explaining a configuration example of a capacitive coupling type plasma processing apparatus.

[0022] 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 introduction unit. The gas introduction unit is capable of introducing 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, 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.

[0023] 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 surrounding 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 support surface for supporting the substrate W, and the annular area 111b is also referred to as a ring support surface for supporting the ring assembly 112.

[0024] 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 arranged on the base 1110. The electrostatic chuck 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 chuck 1111, such as an annular electrostatic chuck or an annular insulating component, may have an annular area 111b. In this case, the ring assembly 112 may be arranged on the annular electrostatic chuck or the annular insulating component, or may be arranged on both the electrostatic chuck 1111 and the annular insulating component.

[0025] 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.

[0026] In addition, the substrate support portion 11 may include a temperature regulating module capable of regulating at least one of the electrostatic chuck 1111, the ring assembly 112 and the substrate to a target temperature. The temperature regulating 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 may flow 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 chuck 1111. In addition, the substrate support portion 11 may include a heat transfer gas supply portion capable of supplying a heat transfer gas to the gap between the back side of the substrate W and the central area 111a.

[0027] The shower head 13 can 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 multiple gas introduction ports 13c. The processing gas supplied to the gas supply port 13a can be introduced into the plasma processing space 10s from the multiple 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 part may include, in addition to the shower head 13, one or more side gas injection parts (SGI: Side Gas Injector) installed in one or more openings formed on the side wall 10a.

[0028] 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 capable of supplying at least one process gas from the gas source 21 corresponding to each other to the shower head 13 via the flow controller 22 corresponding to each other. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Furthermore, 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.

[0029] The exhaust system 40 can be connected to the gas exhaust port 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 can be adjusted by the pressure regulating valve. The vacuum pump can include a turbomolecular pump, a dry pump, or a combination thereof.

[0030] 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 can generate source high frequency electric power RF. The source high frequency electric power RF has a source frequency f RF That is, the source high frequency electric power RF has a frequency of source frequency f RFThe source frequency is a sine wave. RF The frequency may be in the range of 13 MHz to 100 MHz. The high frequency power supply 31 is electrically connected to the high frequency electrode via the matcher 31m, and can supply the source high frequency electric power RF 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. In addition, the upper electrode may include a top plate 13p. When the source high frequency electric power RF is supplied to the high frequency electrode, plasma can be generated from the gas in the chamber 10.

[0031] The matching device 31m has a variable impedance. The variable impedance of the matching device 31m is set so as to reduce reflection of the source high-frequency electric power RF from the load. The matching device 31m can be controlled by the control unit 2, for example.

[0032] The bias power supply 32 is electrically coupled to the substrate support portion 11. The bias power supply 32 is electrically connected to the bias electrode in the substrate support portion 11, and can supply an electric bias EB to the bias electrode. The bias electrode can be a conductive component of the base 1110 or at least one electrode provided in the ceramic component 1111a. The bias electrode can also be shared with the high-frequency electrode. When the electric bias EB is supplied to the bias electrode, ions from the plasma can be attracted to the substrate W.

[0033] The electrical bias EB has a waveform period CY and is periodically supplied to the bias electrode from the bias power supply 32. The waveform period CY of the electrical bias EB is determined by the bias frequency. The bias frequency is, for example, a frequency of 100 kHz to 50 MHz. The time length of the waveform period CY of the electrical bias EB is the inverse of the bias frequency.

[0034] The electric bias EB may be a bias high frequency electric power having a bias frequency (see Figure 4 In other words, the electric bias EB may have a waveform having a sine wave shape 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 32m. The variable impedance of the matching device 32m is set to reduce the reflection of the bias high-frequency electric power from the load.

[0035] Alternatively, the electrical bias EB may also include a voltage pulse (see Figure 3(b) "PV"). The voltage pulse is applied to the bias electrode within the waveform period CY. 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 CY. The waveform of the voltage pulse can be a rectangular wave, a triangular wave, or an arbitrary waveform. The polarity of the voltage of the voltage pulse is set to generate a potential difference between the substrate W and the plasma to attract ions from the plasma to the substrate W. The voltage pulse can be a negative voltage pulse or a negative DC voltage pulse. In the case where the electric bias EB includes a voltage pulse, the plasma processing device 1 may not include the matcher 32m.

[0036] The plasma processing device 1 may further include a directional coupler 31d. The directional coupler 31d is connected between the high frequency power source 31 and the high frequency electrode (or the matching device 31m). The directional coupler 31d can measure the power level of the traveling wave of the source high frequency electric power RF and the power level of the reflected wave of the source high frequency electric power RF.

[0037] Below, with Figure 2 Refer to Figure 3 (a) Figure 3 (b) Figure 4 (a) Figure 4 (b) and Figure 5 , control of each part of the plasma processing apparatus 1 and a plasma processing method according to an exemplary embodiment are described. Figure 3 (a) Figure 3 (b) Figure 4 (a) and Figure 4 (b) is a timing diagram related to a plasma processing apparatus according to an exemplary embodiment. Figure 3 (a) and Figure 4 In (a), ON of the source high frequency electric power RF indicates that the source high frequency electric power RF is being supplied, and OFF of the source high frequency electric power RF indicates that the supply of the source high frequency electric power RF has stopped. In addition, ON of the electric bias EB indicates that the electric bias EB is being supplied, and OFF of the electric bias EB indicates that the supply of the electric bias EB has stopped. Figure 5 is a flow chart of a plasma processing method according to an exemplary embodiment.

[0038] The control unit 2 can perform a plasma processing method (hereinafter referred to as "method MT") by controlling various parts of the plasma processing apparatus 1. In addition, the method MT can also be performed by the pulse control unit 34 described later controlling the high-frequency power supply 31 and the bias power supply 32, or by the control unit 2 and the pulse control unit 34 cooperating to control various parts of the plasma processing apparatus 1. During the execution of the method MT, the substrate W may be placed on the substrate support unit 11 or not. The control unit 2 can control so that Figure 5 Steps STa and STb of method MT are carried out as shown.

[0039] In step STa, the control unit 2 controls the high frequency power source 31 to supply high frequency electric power RF to generate plasma from gas in the chamber 10. Gas from which plasma can be generated is supplied to the chamber 10 from the gas supply unit 20. The pressure in the chamber 10 can be adjusted to a specified pressure by the exhaust system 40.

[0040] In step STb, the control unit 2 controls the bias power supply 32 so as to supply an electrical bias to the substrate supporting unit 11 (or its bias electrode) during the supply of the source high-frequency electric power RF.

[0041] Control unit 2, such as Figure 3 (a) and Figure 4 As shown in (a), the supply of the electric bias EB is delayed by a delay time length DT from the time point when the source high-frequency electric power RF is started to be supplied. The delay time length DT is set to be longer than a reference time length. The reference time length is the time length for electrons to reach the end of the substrate support part 11 or the end of the substrate W from the center of the substrate support part 11 or the center of the substrate W on the substrate support part 11. The delay time length DT can be longer than 300 nanoseconds, longer than 400 nanoseconds, longer than 500 nanoseconds, or longer than 600 nanoseconds. The delay time length DT can be shorter than 3 microseconds, shorter than 2 microseconds, or shorter than 1 microsecond.

[0042] The delay time length DT and the power level of the source high frequency power RF and the source frequency f during the period from the time when the source high frequency power RF starts to be supplied to the time when the electric bias EB starts to be supplied (hereinafter referred to as the "preliminary supply period") are RF , are predetermined. The delay time length DT and the power level and source frequency f of the source high frequency electric power RF during the preceding supply period RF , can be specified from the control unit 2 to the high frequency power source 31. The delay time length DT and the power level and source frequency f of the source high frequency electric power RF during the preceding supply period RF, which is optimized in advance to make the density distribution of plasma or the plasma treatment of the substrate uniform. The density distribution of plasma can also be the luminous intensity distribution in the chamber 10 obtained by the luminescence analyzer 50 through the optical window. The uniformity of the plasma treatment of the substrate can be evaluated based on the in-plane distribution of the etching rate of the substrate or the distribution of the tilt angles of the holes formed on the substrate by etching.

[0043] like Figure 5 As shown, the control unit 2 can repeatedly perform a loop MC including steps STa and STb. In this case, it is determined in step STJ whether the stop condition is satisfied. The stop condition is satisfied when the number of repetitions of loop MC reaches a predetermined number. If the stop condition is not satisfied, loop MC is performed again. If the stop condition is satisfied, method MT ends.

[0044] By repeating the cycle MC, the pulses of the source high frequency electric power RF and the pulses of the electric bias EB can be repeatedly supplied. That is, by repeating the cycle MC, as shown in FIG. Figure 3 (a) and Figure 4 As shown in (a), the supply of source high frequency electric power RF (RF is turned on in the figure) and the supply of source high frequency electric power RF are alternately performed (RF is turned off in the figure). In addition, the supply of electric bias EB (EB is turned on in the figure) and the supply of electric bias EB are alternately stopped (EB is turned off in the figure). The period during which the electric bias EB is turned on (i.e., the pulse ON period BP of the electric bias EB) is as shown in FIG. Figure 3 (b) and Figure 4 As shown in (b), the waveform cycle CY is repeated. That is, during the pulse ON period BP of the electric bias EB, the electric bias EB is periodically supplied with the waveform cycle CY. The period during which the source high-frequency electric power RF is ON (that is, the pulse ON period RP of the source high-frequency electric power RF) and the pulse ON period of the electric bias EB can also be specified by the pulse signal from the pulse control unit 34 to the high-frequency power supply 31 and the bias power supply 32.

[0045] The control unit 2 may further perform step STc. In step STc, the control unit 2 adjusts parameters according to the density distribution of the plasma obtained in the step STa of the previous cycle MC so as to improve the uniformity of the density distribution of the plasma in the subsequent step STa of the cycle MC. The parameters include the delay time length DT and the power level and source frequency f of the source high frequency electric power RF during the previous supply period. RF In addition, as described above, the density distribution of plasma may also be the luminescence intensity distribution in the chamber 10 acquired by the luminescence analyzer 50 .

[0046] In one embodiment, the control unit 2 may adjust the set power level of the source high-frequency electric power RF so that the effective power level of the source high-frequency electric power RF during the preceding supply period is close to the target value. The effective power level is determined as the difference between the power level of the traveling wave and the power level of the reflected wave during the preceding supply period in the preceding cycle MC. The power level of the traveling wave and the power level of the reflected wave can be obtained through the directional coupler 31d. The control unit 2 adjusts the set power level of the source high-frequency electric power RF during the preceding supply period in the subsequent cycle MC so that the determined effective power level is close to the target value.

[0047] In one embodiment, the high frequency power source 31 may be Figure 3 As shown in (b), the source frequency f of the source high-frequency electric power RF is changed within the waveform period CY of the electric bias EB in the repetition period OP. RF , so as to reduce the degree of reflection of the source high frequency electric power RF from its load. Specifically, the high frequency power supply 31 can adjust the source frequency f RF , so as to reduce the multiple phase periods SP within the waveform cycle CY in the repetition period OP (refer to Figure 3 The repetition period OP is a period during which the source high frequency electric power RF and the electric bias EB are supplied simultaneously. The source frequency f of each of the multiple phase periods SP within the waveform period CY is RF , can be set using an initial table prepared in advance. In addition, the source frequency can be adjusted by the first feedback and / or the second feedback described later.

[0048] According to the plasma processing apparatus 1 described above, even if the electric field is locally strong around the substrate support portion 11 or the substrate W at the beginning of plasma ignition, the electric bias EB can be supplied after the electrons reach the entire area of ​​the substrate support portion 11 or the substrate W and plasma is uniformly generated. Therefore, according to the plasma processing apparatus 1, the uniformity of the density distribution of the plasma can be improved.

[0049] Here, the diffusion time of electrons from the center of the substrate W placed on the substrate support 11 to the edge of the substrate W is considered. When the electrons in the plasma conform to the Maxwell distribution, the average speed of the electrons in the x-direction, y-direction, and z-direction orthogonal to each other is <v x >、<v y >、<v z >is expressed by the following formula. Where m is the mass of the electron, k B is the Boltzmann constant, T is the electron temperature. The x and y directions are parallel to the substrate W, and the z direction is perpendicular to the substrate W.

[0050]

[0051] When the electron temperature is 10000K, <v x > and <v y > becomes 3.89×10 5 m / s. Moreover, the magnitude of the velocity in the xy plane is <v x > and <v y > is the square root of the sum of the squares of 5 m / s. Therefore, when the distance from the position on the center of the substrate W to the position on the edge of the substrate W is 150 mm, the time required for the electrons in the plasma to diffuse from the position on the center of the substrate W to the position on the edge of the substrate W is 272 nanoseconds. Therefore, when the delay time length DT is 300 ns or more, the electric bias EB can be supplied after the electrons are sufficiently diffused on the substrate W and the plasma is uniformly generated.

[0052] Next, the first feedback and the second feedback are described.

[0053] [1st Feedback]

[0054] The first feedback is performed to adjust the source frequency in the multiple phase periods SP in each of the multiple continuous waveform cycles CY within the repetition period OP. The multiple waveform cycles CY each include N phase periods SP(1) to SP(N). N is an integer greater than 2. The N phase periods SP(1) to SP(N) divide the multiple waveform cycles CY into N phase periods. In the following description, the waveform cycle CY(m) represents the mth waveform cycle in the multiple continuous waveform cycles CY. The phase period SP(n) represents the nth phase period in the phase periods SP(1) to SP(N). In addition, the phase period SP(m,n) represents the nth phase period in the waveform cycle CY(m).

[0055] The source frequency in the first feedback can be adjusted by the high frequency power source 31. The high frequency power source 31 can adjust the source frequency of the source high frequency power RF in the phase period SP(m,n) according to the change in the degree of reflection of the source high frequency power RF.

[0056] In order to determine the degree of reflection of the source high frequency electric power RF, the plasma processing device 1 can use a directional coupler 31d. The power level Pr of the reflected wave measured by the directional coupler 31d is notified to the high frequency power supply 31. In addition, the power level Pf of the traveling wave can also be notified to the high frequency power supply 31 from the directional coupler 31d.

[0057] The plasma processing device 1 may further include a sensor 31s. The sensor 31s includes a voltage sensor and a current sensor. The sensor 31s can measure a voltage V in a power supply path connecting the high-frequency power source 31 and the high-frequency electrode to each other. RF and current I RF The source high frequency electric power RF is supplied to the high frequency electrode via the power supply path. The sensor 31s may be provided between the high frequency power source 31 and the matching device 31m. The voltage V RF and current I RF The high frequency power supply 31 is notified.

[0058] The high frequency power source 31 generates a representative value from the measured values ​​in each of the multiple phase periods SP. The measured value may be the power level Pr of the reflected wave acquired by the directional coupler 31d. The measured value may also be the value of the ratio of the power level Pr of the reflected wave to the output power level of the source high frequency electric power RF (i.e., reflectivity). The measured value may also be the voltage V obtained by the sensor 31s in each of the multiple 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 in each of the multiple phase periods SP. The impedance Z can be obtained from the voltage V obtained by the sensor 31s. RF and current I RF The representative value may be an average value or a maximum value of the measured values ​​in each of the plurality of phase periods SP. The high-frequency power source 31 uses the representative value in each of the plurality of phase periods SP as a value indicating the degree of reflection of the source high-frequency electric power RF.

[0059] In the first feedback, the high-frequency power source 31 determines the change in the degree of reflection by using source frequencies different from each other in corresponding phase periods SP(n) in each of two or more waveform periods CY before the waveform period CY(m).

[0060] By using different source frequencies in the phase period SP(n) in each of two or more waveform periods CY, the relationship between the change in source frequency (frequency shift) and the change in the degree of reflection of the source high-frequency electric power can be determined. Therefore, according to the plasma processing device 1, the source frequency used in the phase period SP(m,n) can be adjusted in accordance with the change in the degree of reflection so as to reduce the degree of reflection. In addition, according to the plasma processing device 1, the degree of reflection can be reduced at a high speed in each of the plurality of waveform periods CY in which the electrical bias EB is provided to the bias electrode of the substrate support portion 11.

[0061] In one embodiment, the two or more waveform periods CY before the waveform period CY(m) include the waveform period CY(m-M1) and the waveform period CY(m-M2). Here, M1 and M2 are natural numbers satisfying M1>M2. In one embodiment, the waveform period CY(m-M1) is the waveform period CY(m-2Q), and the waveform period CY(m-M2) is the waveform period CY(mQ). "Q" and "M2" can be "1", and "2Q" and "M1" can be "2". "Q" can also be an integer greater than 2.

[0062] In the first feedback, the high-frequency power supply 31 imparts a frequency shift in one direction (frequency shift on one side) from the source frequency f(m-M1,n) to the source frequency f(m-M2,n). Here, f(m,n) represents the source frequency of the source high-frequency electric power RF used in the phase period SP(m,n). f(m,n) is represented by f(m,n)=f(m-M2,n)+Δ(m,n). Δ(m,n) represents the amount of frequency shift. The frequency shift in one direction is one of a decrease in frequency and an increase in frequency. If the frequency shift in one direction is a decrease in frequency, Δ(m,n) has a negative value. If the frequency shift in one direction is an increase in frequency, Δ(m,n) has a positive value.

[0063] In the first feedback, when the degree of reflection is reduced by using the source frequency f(m-M2,n) obtained by frequency shifting in one direction, the high-frequency power supply 31 sets the source frequency f(m,n) to a frequency having a frequency shift in one direction relative to the source frequency f(m-M2,n). For example, when the power level Pr(m-M2,n) is reduced from the power level Pr(m-M1,n) by frequency shifting in one direction, the high-frequency power supply 31 sets the source frequency f(m,n) to a frequency having a frequency shift in one direction relative to the source frequency f(m-M2,n). Wherein, Pr(m,n) represents the power level Pr of the reflected wave of the source high-frequency electric power RF in the phase period SP(m,n).

[0064] In the first feedback, a situation may occur where the degree of reflection increases due to the use of the source frequency f(m-M2,n) obtained by frequency shifting in one direction. For example, a situation may occur where the power level Pr(m-M2,n) of the reflected wave increases from the power level Pr(m-M1,n) of the reflected wave due to frequency shifting in one direction. In this case, the high-frequency power supply 31 may set the source frequency f(m,n) to a frequency having a frequency shift in another direction (frequency shift on the other side) relative to the source frequency f(m-M2,n).

[0065] In another embodiment, the source frequency of the source high-frequency electric power RF in the phase period SP(m,n) can be obtained as a frequency that minimizes the degree of reflection based on the degree of reflection (for example, power level Pr) obtained by using different source frequencies in the corresponding phase period SP(n) of each of the two or more waveform periods CY before the waveform period CY(m). The frequency that minimizes the degree of reflection can be obtained by using the least square method of each of the different frequencies and the corresponding degree of reflection.

[0066] [2nd Feedback]

[0067] Next, the second feedback is described. In the following description, the waveform period CY(m) represents the mth waveform period among the multiple waveform periods CY(1) to CY(M) in each of the multiple repetition periods OP. In addition, the waveform period CY(k, m) represents the mth waveform period in the kth repetition period. In addition, the phase period SP(n) represents the nth phase period among the multiple phase periods SP(1) to SP(N) in each of the multiple waveform periods CY in the multiple repetition periods OP. In addition, the phase period SP(m, n) represents the nth phase period in the waveform period CY(m). In addition, the phase period SP(k, m, n) represents the nth phase period in the waveform period CY(m) in the kth repetition period OP(k).

[0068] The source frequency of each of the multiple phase periods SP in each of the multiple waveform cycles CY in the repetition period OP(1) to OP(T-1) can be obtained by performing the above-mentioned first feedback. Here, T is an integer greater than 3. Alternatively, the source frequency of each of the multiple phase periods SP in each of the multiple waveform cycles CY in the repetition period OP(1) to OP(T-1) can be set to the frequency registered in the pre-prepared initial table.

[0069] The second feedback can be used to adjust the source frequency of the source high-frequency electric power RF in the repetition period after the repetition period OP(T). In the second feedback, the high-frequency power supply 31 adjusts the source frequency f(k, m, n) in accordance with the change in the degree of reflection of the source high-frequency electric power RF. In the second feedback, the change in the degree of reflection is determined by using the source frequencies of the source high-frequency electric power RF that are different from each other in the corresponding phase period SP(n) in the waveform period CY(m) in more than two repetition periods OP before the repetition period OP(k).

[0070] In the second feedback, by using different source frequencies in the same phase period within the same waveform period in each of more than two repetition periods OP, the relationship between the change in source frequency (frequency shift) and the change in the degree of reflection of the source high-frequency electric power can be determined. Therefore, by adopting the second feedback, the source frequency used in the phase period SP (k, m, n) can be adjusted in accordance with the change in the degree of reflection so as to reduce the degree of reflection. In addition, by adopting the second feedback, the degree of reflection can be reduced at a high speed in each of the multiple waveform periods CY in each of the multiple repetition periods OP.

[0071] In one embodiment, the two or more repetition periods OP before the repetition period OP(k) include the (k-K1)th repetition period OP(k-K1) and the (k-K2)th repetition period OP(k-K2). Here, K1 and K2 are natural numbers satisfying K1>K2.

[0072] In one embodiment, the repetition period OP(k-K1) is the repetition period OP(k-2). The repetition period OP(k-K2) is the repetition period after the repetition period OP(k-K1), and in one embodiment, is the repetition period OP(k-1). That is, in one embodiment, K2 and K1 are 1 and 2, respectively.

[0073] The high-frequency power supply 31 imparts a frequency shift in one direction (frequency shift on one side) from the source frequency in the phase period SP (k-K1, m, n) to the source frequency f (k-K2, m, n) in the phase period SP (k-K2, m, n). Here, f (k, m, n) represents the source frequency of the source high-frequency electric power RF used in the phase period SP (k, m, n). f (k, m, n) is represented by f (k, m, n) = f (k-K2, m, n) + Δ (k, m, n). Δ (k, m, n) represents the amount of frequency shift. The frequency shift in one direction is one of a decrease in frequency and an increase in frequency. If the frequency shift in one direction is a decrease in frequency, Δ (k, m, n) has a negative value. If the frequency shift in one direction is an increase in frequency, Δ (k, m, n) has a positive value.

[0074] In the second feedback, when the degree of reflection is reduced when using the source frequency f(k-K2,m,n) obtained by frequency shifting in one direction, the high-frequency power supply 31 sets the source frequency f(k,m,n) to a frequency having a frequency shift in one direction relative to the source frequency f(k-K2,m,n). For example, when the power level Pr(k-K2,m,n) is reduced from the power level Pr(k-K1,m,n) by frequency shifting in one direction, the high-frequency power supply 31 sets the source frequency f(k,m,n) to a frequency having a frequency shift in one direction relative to the source frequency f(k-K2,m,n). Wherein, Pr(k,m,n) represents the power level Pr of the reflected wave of the source high-frequency electric power RF in the phase period SP(k,m,n).

[0075] In the second feedback, a situation may occur where the degree of reflection increases due to the use of the source frequency f(k-K2,m,n) obtained by frequency shifting in one direction. For example, a situation may occur where the power level Pr(k-K2,m,n) of the reflected wave increases from the power level Pr(k-K1,m,n) of the reflected wave due to frequency shifting in one direction. In this case, the high-frequency power supply 31 may set the source frequency f(k,m,n) to a frequency having a frequency shift in another direction (frequency shift on the other side) relative to the source frequency f(k-K2,m,n).

[0076] In another embodiment, the plurality of repetition periods OP may include from the 1st to the Kth a The repetition period OP(1)~OP(K a ). Here, K a is a natural number greater than 2. The high frequency power source 31 can be repeated during the period OP(1) to OP(K a ) each of which includes a plurality of waveform cycles CY from the 1st to the Mth a Waveform cycles CY(1)~CY(M a ) each performs initial processing. Here, M a is a natural number. In the initial processing, the waveform period CY(1) to CY(M a ) each having a plurality of frequency sets, and the plurality of frequency sets included in the frequency set group may be different from each other. In addition, the repetition periods OP(1) to OP(K) may be used. a ) respectively, and these multiple frequency groups can be different from each other. The high frequency power source 31 repeats during the period OP(1) to OP(K a ) The 1st to the Mth a Waveform cycles CY(1)~CY(M a) In each of the multiple phase periods SP, multiple frequencies included in the corresponding frequency set are used as source frequencies. In addition, multiple frequency sets and multiple frequency set groups can be stored in the storage unit of the control unit 2 or the high-frequency power supply 31.

[0077] It can be that the high frequency power source 31 is in the repetition period OP(1) to OP(K a ) respectively, in the waveform period CY (M a ) and then the first feedback is performed. That is, the high frequency power supply 31 may be repeated during the period OP(1) to OP(K a ) each includes a waveform period CY(M a +1) to CY(M), the above-mentioned first feedback is performed.

[0078] In one embodiment, the multiple repetition periods OP may further include the first (K a +1) to Kth b Repeat period OP(K a +1)~OP(K b ). Here, K b Yes (K a +1) or more, can be a natural number that satisfies K b =K a +1.

[0079] It can be that the high frequency power supply 31 is in the repetition period OP(K a +1)~OP(K b ) each includes the first to the Mth of the plurality of waveform cycles CY b1 Waveform cycles CY(1)~CY(M b1 ) each performs the above-mentioned initial processing. Here, M b1 is a natural number. It can be M b1 and M a Meet M b1 <M a .

[0080] It can be that the high frequency power supply 31 is in the repetition period OP(K a +1)~OP(K b ) each includes a plurality of waveform cycles CY of the first (M b1 +1) to the Mth b2 Waveform period CY(M b1 +1)~CY(M b2 ), the above-mentioned second feedback is performed. Here, M b2 Is to satisfy M b2 >M b1 A natural number.

[0081] It can be that the high frequency power supply 31 is in the repetition period OP(K a +1)~OP(K b ) respectively, in the waveform period CY(M b2 ) and then the first feedback is performed. That is, the high frequency power supply 31 may be repeated during the period OP(K a +1)~OP(K b ) each includes a waveform period CY(M b2 +1) to CY(M), the above-mentioned first feedback is performed.

[0082] In addition, the high frequency power supply 31 may be b +1) to the last repetition period OP(K b +1) to OP(K) respectively include the 1st to Mth c Waveform cycles CY(1)~CY(M c ), the above-mentioned second feedback is performed. Here, M c is a natural number. In addition, it can be that the high-frequency power supply 31 is repeated during OP (K b +1)~OP(K), in each of the waveform periods CY(M c ) and then the first feedback is performed. That is, the high frequency power supply 31 may be repeated during the period OP(K b +1)~OP(K) respectively include the waveform period CY(M c +1) to CY(M), the above-mentioned first feedback is performed.

[0083] In another embodiment, in the first feedback, the source frequency of the source high-frequency electric power RF in the phase period SP(k,m,n) is obtained as a frequency that minimizes the degree of reflection based on two or more degrees of reflection (for example, power level Pr) obtained by using source frequencies of the source high-frequency electric power RF that are different from each other in the corresponding phase periods SP(n) of two or more waveform periods CY before the waveform period CY(k,m) within the repetition period OP(k). The frequency that minimizes the degree of reflection can be obtained by using the least square method of each of the different frequencies and the corresponding degree of reflection.

[0084] Furthermore, in the second feedback, the source frequency f(k, m, n) may be obtained as a frequency that minimizes the degree of reflection based on two or more degrees of reflection (e.g., power level Pr) obtained by using source frequencies of source high-frequency electric power RF that are different from each other in the corresponding phase period SP(n) within the waveform cycle CY(m) of two or more repetition periods OP before the repetition period OP(k). The frequency that minimizes the degree of reflection can be obtained by using the least square method of each of the different frequencies and the corresponding degree of reflection.

[0085] 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.

[0086] Here, various exemplary embodiments included in the present invention are described in the following [E1] to [E10].

[0087] [E1]

[0088] A plasma processing device, characterized in that it comprises:

[0089] Chamber;

[0090] a substrate support portion disposed within the chamber;

[0091] A high frequency power source capable of generating high frequency electric power;

[0092] a bias power supply electrically coupled to the substrate support and capable of generating an electrical bias for attracting ions to the substrate support; and

[0093] a control unit capable of controlling the high frequency power supply and the bias power supply,

[0094] The control unit is capable of controlling so as to execute:

[0095] Step (a), supplying high frequency electric power to the source to generate plasma in the chamber; and

[0096] Step (b), supplying the electric bias to the substrate support portion during supplying the source high frequency electric power,

[0097] The control unit is capable of setting the delay time length from the time point when the source high-frequency electric power is started to be supplied in the step (a) to the time point when the electric bias is started to be supplied in the step (b) to be longer than the reference time length,

[0098] The reference time length is the time length for electrons to reach the end of the substrate support part or the end of the substrate from the center of the substrate support part or the center of the substrate on the substrate support part.

[0099] In the embodiment [E1], even if the electric field is locally strong around the substrate support or the substrate at the beginning of plasma ignition, the electric bias can be supplied after the electrons reach the entire area of ​​the substrate support or the substrate and the plasma is uniformly generated. Therefore, the uniformity of the density distribution of the plasma can be improved.

[0100] [E2]

[0101] The plasma processing device as described in [E1] is characterized in that the delay time length is greater than 300 nanoseconds.

[0102] [E3]

[0103] The plasma processing device as described in [E1] or [E2] is characterized in that the electrical bias is a bias high-frequency electric power or a periodic voltage pulse.

[0104] [E4]

[0105] A plasma processing device as described in any one of [E1] to [E3] is characterized in that the high-frequency power supply is capable of changing the source frequency of the source high-frequency electric power within the waveform period of the electrical bias so as to reduce the degree of reflection of the source high-frequency electric power from the load.

[0106] [E5]

[0107] The plasma processing device as described in any one of [E1] to [E4], characterized in that:

[0108] The control unit is capable of performing control so that:

[0109] Repeating the cycle including the step (a) and the step (b) to repeatedly supply the pulses of the source high frequency electric power and the pulses of the electric bias, and

[0110] During the repetition of the cycle, the delay time length, the power level of the source high-frequency electric power and the source frequency of the source high-frequency electric power are adjusted according to the density distribution of the plasma obtained in the previous step (a), so as to improve the uniformity of the density distribution of the plasma in the subsequent step (a).

[0111] [E6]

[0112] A plasma treatment method, comprising:

[0113] Step (a), supplying high frequency electric power from a high frequency power source to generate plasma in a chamber of a plasma processing device; and

[0114] step (b), supplying an electrical bias from a bias power supply to a substrate support portion disposed in the chamber to attract ions to the substrate support portion,

[0115] The delay time length from the time when the source high frequency electric power starts to be supplied in the step (a) to the time when the electric bias starts to be supplied in the step (b) is set to be longer than the reference time length,

[0116] The reference time length is the time length for electrons to reach the end of the substrate support part or the end of the substrate from the center of the substrate support part or the center of the substrate on the substrate support part.

[0117] [E7]

[0118] The plasma processing method as described in [E6] is characterized in that the delay time length is greater than 300 nanoseconds.

[0119] [E8]

[0120] The plasma processing method as described in [E6] or [E7] is characterized in that the electrical bias is a bias high-frequency electric power or a periodic voltage pulse.

[0121] [E9]

[0122] The plasma processing method as described in any one of [E6] to [E8] is characterized in that the source frequency of the source high-frequency electric power is changed within the waveform period of the electrical bias so as to reduce the degree of reflection of the source high-frequency electric power from the load.

[0123] [E10]

[0124] The plasma processing method as described in any one of [E6] to [E9], characterized in that it also includes:

[0125] a repetitive step of repeatedly performing a cycle including the step (a) and the step (b) so that the pulses of the source high-frequency electric power and the pulses of the electric bias are repeatedly supplied; and

[0126] An adjustment process, in which the delay time length, the power level of the source high-frequency electric power and the source frequency of the source high-frequency electric power are adjusted in accordance with the density distribution of the plasma obtained in the previous process (a) during the repetition of the cycle, so as to improve the uniformity of the density distribution of the plasma in the subsequent process (a).

[0127] It should be understood from the above description that the 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 spirit of the present invention. Therefore, the various embodiments disclosed in this specification are not intended to be limited, and the true scope and spirit are represented by the attached claims.

[0128] Description of Reference Numerals

[0129] 1 ... plasma processing apparatus, 2 ... control unit, 10 ... chamber, 11 ... substrate support unit, 31 ... high frequency power supply, 32 ... bias power supply.

Claims

1. A plasma processing device, characterized in that: include: Chamber; a substrate support portion disposed within the chamber; A high frequency power source capable of generating high frequency electric power; a bias power supply electrically coupled to the substrate support and capable of generating an electrical bias for attracting ions to the substrate support; and a control unit capable of controlling the high frequency power supply and the bias power supply, The control unit is capable of controlling so as to execute: Step (a), supplying high frequency electric power to the source to generate plasma in the chamber; and Step (b), supplying the electric bias to the substrate support portion during supplying the source high frequency electric power, The control unit is capable of setting the delay time length from the time point when the source high-frequency electric power is started to be supplied in the step (a) to the time point when the electric bias is started to be supplied in the step (b) to be longer than the reference time length, The reference time length is the time length for electrons to reach the end of the substrate support part or the end of the substrate from the center of the substrate support part or the center of the substrate on the substrate support part.

2. The plasma processing device according to claim 1, wherein: The delay time length is greater than 300 nanoseconds.

3. The plasma processing device according to claim 1 or 2, characterized in that: The electrical bias is biased high frequency electric power or periodic voltage pulses.

4. The plasma processing device according to claim 1 or 2, characterized in that: The high-frequency power supply is capable of changing the source frequency of the source high-frequency electric power within a waveform period of the electrical bias so as to reduce the degree of reflection of the source high-frequency electric power from a load.

5. The plasma processing device according to claim 1 or 2, characterized in that: The control unit is capable of performing control so that: Repeating the cycle including the step (a) and the step (b) to repeatedly supply the pulses of the source high frequency electric power and the pulses of the electric bias, and During the repetition of the cycle, the delay time length, the power level of the source high-frequency electric power and the source frequency of the source high-frequency electric power are adjusted according to the density distribution of the plasma obtained in the previous step (a), so as to improve the uniformity of the density distribution of the plasma in the subsequent step (a).

6. A plasma treatment method, characterized in that: include: Step (a), supplying high frequency electric power from a high frequency power source to generate plasma in a chamber of a plasma processing device; and step (b), supplying an electrical bias from a bias power supply to a substrate support portion disposed in the chamber to attract ions to the substrate support portion, The delay time length from the time when the source high frequency electric power starts to be supplied in the step (a) to the time when the electric bias starts to be supplied in the step (b) is set to be longer than the reference time length, The reference time length is the time length for electrons to reach the end of the substrate support part or the end of the substrate from the center of the substrate support part or the center of the substrate on the substrate support part.

7. The plasma processing method according to claim 6, wherein: The delay time length is greater than 300 nanoseconds.

8. The plasma treatment method according to claim 6 or 7, characterized in that: The electrical bias is biased high frequency electric power or periodic voltage pulses.

9. The plasma treatment method according to claim 6 or 7, characterized in that: Also includes: The source frequency of the source high-frequency electric power is changed within a waveform period of the electrical bias so as to reduce the degree of reflection of the source high-frequency electric power from a load.

10. The plasma processing method according to claim 6 or 7, characterized in that: Also includes: A repetitive step of repeatedly performing a cycle including the step (a) and the step (b) so that the pulses of the source high-frequency electric power and the pulses of the electric bias are repeatedly supplied; and An adjustment process, in which the delay time length, the power level of the source high-frequency electric power and the source frequency of the source high-frequency electric power are adjusted in accordance with the density distribution of the plasma obtained in the previous process (a) during the repetition of the cycle, so as to improve the uniformity of the density distribution of the plasma in the subsequent process (a).

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