Apparatus and method for controlling plasma characteristics and system for processing substrates

Abstract

An apparatus for controlling plasma characteristics includes one or more processors, and a storage medium storing computer-readable instructions. When executed by the one or more processors, the computer readable instructions are configured to cause the one or more processors to obtain an equivalent circuit as seen from a non-sinusoidal generator for applying a plasma control voltage to an electrostatic chuck disposed in a processing space of the processing chamber; and controls the characteristics of the plasma generated in the processing space on the basis of the obtained equivalent circuit. A characteristic of the plasma includes at least one of a first sheath thickness from the substrate to the plasma, and a second sheath thickness from a showerhead that injects a process gas into the processing space to the plasma.

Description

[0001] Cross - reference to related applications

[0002] This application claims priority to Korean Patent Application No. 10 - 2023 - 0195918, filed with the Korean Intellectual Property Office on December 29, 2023, the disclosure of which is incorporated herein by reference in its entirety. Technical field

[0003] The present disclosure relates to an apparatus and method for controlling plasma characteristics and a system for processing a substrate. Background art

[0004] When forming a predetermined pattern on a substrate, various unit processes such as a deposition process, a lithography process, and an etching process can be continuously performed in a device used in a semiconductor manufacturing process.

[0005] Among these processes, the etching process is a process for removing a film formed on a substrate, and depending on the way the process is carried out, the etching process can be classified as a wet etching process or a dry etching process. Among them, in the dry etching process, plasma is generated in a processing chamber to etch a film formed on a substrate, and in order to obtain uniform etching, it is necessary to accurately calculate the characteristics of the plasma. Summary of the invention

[0006] One aspect of the present disclosure provides an apparatus and method for controlling plasma characteristics and a system for processing a substrate, in which a film formed on the substrate can be etched uniformly.

[0007] According to one aspect of the present disclosure, an apparatus for controlling plasma characteristics includes one or more processors and a storage medium storing computer - readable instructions. When executed by the one or more processors, the computer - readable instructions are configured to cause the one or more processors to obtain an equivalent circuit seen from a non - sine generator that applies a plasma control voltage to an electrostatic chuck disposed in a processing space of a processing chamber; and control characteristics of the plasma generated in the processing space based on the obtained equivalent circuit. The characteristics of the plasma include at least one of the following: a first sheath thickness from the substrate to the plasma, and a second sheath thickness from a showerhead that injects a process gas into the processing space to the plasma.

[0008] One or more processors may remove the component generated by the RF power supply unit from the voltage and current output by a power supply unit that applies a voltage to an electrostatic chuck. The power supply unit includes: an RF power supply unit that applies a plasma generation voltage for generating plasma, and a non-sinusoidal generator that applies a plasma control voltage for controlling the characteristics of the generated plasma. One or more processors may obtain an equivalent circuit seen from the non-sinusoidal generator based on the voltage and current from which the component generated by the RF power supply unit has been removed.

[0009] The equivalent circuit may be an R-C equivalent circuit composed of an equivalent resistance and an equivalent capacitance.

[0010] One or more processors may estimate the resistance and capacitance as the equivalent resistance and equivalent capacitance when the error between the measured current value and the current value obtained by separately changing the equivalent resistance and equivalent capacitance based on the voltage-current relationship is less than a preset value.

[0011] The voltage-current relationship may be determined by the following mathematical expression:

[0012] , where I(t) is the current from which the component generated by the RF power supply unit has been removed, V(t) is the voltage from which the component generated by the RF power supply unit has been removed, ω is the frequency, R L is the equivalent resistance, C L is the equivalent capacitance, and V'(t) is the differential value of V(t).

[0013] The equivalent capacitance and equivalent resistance may be estimated for each of the (+) polarity and (-) polarity of the plasma control voltage.

[0014] One or more processors may perform low-pass filtering or moving average on each of the measured voltage and the measured current.

[0015] The voltage applied from the power supply unit may be a voltage obtained by impedance-matching the plasma generation voltage and then adding the impedance-matched plasma generation voltage and the plasma control voltage.

[0016] The equivalent capacitance may have a value that varies according to the polarity and amplitude of the plasma control voltage.

[0017] The first sheath thickness may have a value that increases as the amplitude of the plasma control voltage with (-) polarity increases, and the second sheath thickness may have a value that increases as the amplitude of the plasma control voltage with (+) polarity increases.

[0018] One or more processors may increase the first sheath thickness by increasing the magnitude of the plasma control voltage of (-) polarity, or one or more processors may increase the second sheath thickness by increasing the magnitude of the plasma control voltage of (+) polarity.

[0019] The first sheath thickness (t sp ) can be determined according to the following mathematical expression: , where t sp is the first sheath thickness, ε0 is the permittivity, A is the cross-sectional area of the electrostatic chuck, C L is the equivalent capacitance when the plasma control voltage has (-) polarity, C st is the equivalent capacitance of the transmission line and the processing chamber, and C ch is the capacitance of the dielectric provided on the upper surface of the electrostatic chuck.

[0020] The second sheath thickness can be determined according to the following mathematical expression: , where t sg is the second sheath thickness, ε0 is the permittivity, A is the cross-sectional area of the electrostatic chuck, C L is the equivalent capacitance when the plasma control voltage has (+) polarity, C st is the equivalent capacitance of the processing chamber, and C ch is the capacitance of the dielectric provided on the upper surface of the electrostatic chuck.

[0021] The equivalent capacitance can be determined according to the following mathematical expression: C L = C st + C ch || (C p,sh + C g,sh ), where C L is the equivalent capacitance, C st is the equivalent capacitance of the transmission line and the processing chamber, C ch is the capacitance of the dielectric provided on the upper surface of the electrostatic chuck, C p,sh is the capacitance between the plasma and the substrate, and C g,sh is the capacitance between the plasmas in the showerhead.

[0022] When the polarity of the plasma control voltage is (+), C p,sh can be 0, and when the polarity of the plasma control voltage is (-), C g,sh can be 0.

[0023] The equivalent resistance can be determined according to the following mathematical expression: R L ≒ R p , where R L is the equivalent resistance, and Rp is the resistance of the bulk plasma.

[0024] The plasma control voltage can be a pulsed voltage.

[0025] According to one aspect of the present disclosure, a method of controlling plasma characteristics includes: a first operation of obtaining an equivalent circuit seen from a non-sinusoidal generator that applies a plasma control voltage to an electrostatic chuck disposed in a processing space of a processing chamber; and a second operation of controlling characteristics of the plasma generated in the processing space based on the obtained equivalent circuit. The characteristics of the plasma include at least one of the following: a first sheath thickness from a substrate to the plasma, and a second sheath thickness from a showerhead that injects a process gas into the processing space to the plasma.

[0026] The second operation can increase the first sheath thickness (t sp ) by increasing the magnitude of the plasma control voltage of the (-) polarity, or can increase the second sheath thickness (t sg ) by increasing the magnitude of the plasma control voltage of the (+) polarity.

[0027] According to one aspect of the present disclosure, a system for processing a substrate includes: a processing chamber having a processing space in which a substrate can be processed; a showerhead installed in an upper portion of the processing space in the processing chamber and injecting a process gas for processing the substrate into the processing space; an electrostatic chuck installed in a lower side of the processing space in the processing chamber to face the showerhead vertically and having a substrate mounted thereon; and a plasma characteristic control device for controlling characteristics of the plasma based on an equivalent circuit. The plasma characteristic control device includes: a power supply unit that applies a voltage to the electrostatic chuck, the power supply unit including an RF power supply unit that applies a plasma generation voltage for generating a plasma and a non-sinusoidal generator that applies a plasma control voltage for controlling characteristics of the generated plasma; a measurement unit that measures a voltage and a current output from the power supply unit; and a control unit that removes a component generated by the RF power supply unit from the voltage and the current measured by the measurement unit, obtains an equivalent circuit seen from the non-sinusoidal generator based on the voltage and the current from which the component generated by the RF power supply unit has been removed, and then controls characteristics of the plasma based on the obtained equivalent circuit. The characteristics of the plasma include at least one of the following: a first sheath thickness from a substrate to the plasma, and a second sheath thickness from a showerhead that injects a process gas into the processing space to the plasma. The control unit increases the first sheath thickness by increasing the magnitude of the plasma control voltage of the (-) polarity, or increases the second sheath thickness by increasing the magnitude of the plasma control voltage of the (+) polarity. Description of the Drawings

[0028] The above and other aspects, features, and advantages of the present disclosure will be more clearly understood from the following detailed description in conjunction with the accompanying drawings, in which:

[0029] Figure 1 A system for processing a substrate including a device for controlling plasma characteristics according to an embodiment is shown;

[0030] Figures 2A to 2D An equivalent circuit according to an embodiment is shown;

[0031] Figures 3A to 3C A graph showing that a first sheath thickness and a second sheath thickness according to an embodiment change according to the polarity and amplitude of a plasma control voltage;

[0032] Figure 4 A flowchart showing a method for controlling plasma characteristics according to an embodiment;

[0033] Figure 5 Is shown in detail Figure 4 Of operation S410; and

[0034] Figure 6 A block diagram of a computing device according to an embodiment, which can fully or partially implement a control unit of a device for controlling plasma characteristics. Detailed Description of Specific Embodiments

[0035] Hereinafter, specific embodiments will be described with reference to the accompanying drawings. The following detailed description is provided to provide a comprehensive understanding of the methods, devices, and / or systems described herein. However, this is only an example, and the present disclosure is not limited thereto.

[0036] When describing embodiments, if it is determined that a detailed description of known technologies related to the present disclosure may unnecessarily obscure the subject matter of the present disclosure, the detailed description will be omitted. Additionally, the terms described later are terms defined in consideration of their functions in the present disclosure, and they may vary according to the intention or habit of the user or operator. Therefore, they should be defined based on the content of the entire specification. The technical terms used in the detailed description are only for describing embodiments and should not be construed as limiting. Unless clearly used otherwise, expressions in the singular form include the plural form. In this specification, expressions such as "including", "comprising", and "provided with" are intended to indicate any characteristic, number, step, operation, element, part, or combination thereof, and should not be construed as excluding the existence or possibility of one or more other characteristics, numbers, steps, operations, elements, parts, or combinations thereof other than those described.

[0037] Figure 1FIG. 0 shows a system for processing a substrate including an apparatus for controlling plasma characteristics according to an embodiment.

[0038] Referring Figure 1 , the system 1 for processing a substrate may include a processing chamber 20, a substrate support 30, a first gas supply unit 40, a second gas supply unit 60, a liner (liner or wall liner) 70, a baffle unit 80, and an apparatus 100 for controlling plasma characteristics.

[0039] The system 1 for processing a substrate according to the present disclosure is a system that processes a substrate (W) using a dry etching process and may process the substrate (W) using, for example, a plasma process.

[0040] As Figure 1 shown, the processing chamber 20 is formed with a processing space (A) in which the substrate (W) can be processed, and a plasma process can be performed in the processing space (A).

[0041] In addition, the processing chamber 20 may have an exhaust hole 21 formed in its lower portion. The exhaust hole 21 may be connected to an exhaust pipe line 23 equipped with a pump 22, and the exhaust hole 21 may discharge reaction by-products generated during the plasma process and gases remaining in the processing chamber 20 to the outside of the processing chamber 20 through the exhaust pipe line 23. In this case, the processing space (A) of the processing chamber 20 may be depressurized to a predetermined pressure.

[0042] In addition, the processing chamber 20 may have a valve 24 formed on its side wall. The valve 24 may serve as a passage for the substrate (W) to enter and exit the processing space (A) of the processing chamber 20 and may be configured to be opened and closed by a door assembly 25.

[0043] For example, the door assembly 25 may be configured to include a door body 25a and a door driving unit 25b. More specifically, the door body 25a may be formed on the outer wall of the processing chamber 20 at a position corresponding to the valve 24. The door body 25a may be moved up and down (in the height direction of the processing chamber 20) by the door driving unit 25b. Any type of driving device (e.g., a combination of a motor and a gear, a pneumatic cylinder, an electric cylinder, a hydraulic cylinder, etc.) that can linearly reciprocate the door body 25a may be used as the door driving unit 25b for driving the door body 25a.

[0044] The substrate support 30 is installed on the lower side of the processing space (A) to be vertically opposed to the showerhead 10 in the processing chamber 20, and the substrate (W) can be placed on the upper surface of the substrate support 30. The substrate support 30 can support the substrate (W) using electrostatic force to effectively support the substrate (W) in the processing space (A) in a vacuum environment. However, the support of the substrate support 30 for the substrate (W) is not necessarily limited to this, and the substrate (W) can also be supported in various ways (e.g., mechanical clamping or vacuum).

[0045] In the case of using electrostatic force to support the substrate (W) as in the present disclosure, the substrate support 30 can be configured to include a base 31 and an electrostatic chuck (ESC) 32.

[0046] For example, the electrostatic chuck 32 uses electrostatic force to support the substrate (W) placed on its upper surface, can be formed of a ceramic material, and can be combined with the base 31 to be fixed on the base 31.

[0047] In addition, the electrostatic chuck 32 can be installed to be movable up and down (in the height direction of the processing chamber 20) in the processing chamber 20 using a separate driving member (not shown). In this way, when the electrostatic chuck 32 is formed to be movable up and down, the substrate (W) can be positioned in a region where a more uniform plasma distribution is exhibited.

[0048] In addition, the ring assembly 33 can be formed to surround the edge of the electrostatic chuck 32 in an annular shape. The ring assembly 33 can be formed in an annular shape and is configured to support the edge region of the substrate (W).

[0049] The ring assembly 33 can be configured to include a focusing ring 33a and an insulating ring 33b. For example, the focusing ring 33a can be formed inside the insulating ring 33b and can be formed to surround the electrostatic chuck 32. The focusing ring 33a can be formed of a silicon material and can focus the plasma (PM) onto the substrate (W). In addition, the insulating ring 33b can be formed to surround the focusing ring 33a outside the focusing ring 33a. The insulating ring 33b can be formed of a quartz material.

[0050] In addition, the ring assembly 33 can further include an edge ring formed to be in close contact with the edge of the focusing ring 33a. The edge ring can be formed to prevent the side of the electrostatic chuck 32 from being damaged by the plasma (PM).

[0051] The first gas supply unit 40 can supply gas to remove foreign substances remaining on the upper part of the ring assembly 33 or the edge portion of the electrostatic chuck 32. The first gas supply unit 40 can be configured to include a first gas supply source 41 and a first gas supply pipeline 42.

[0052] The first gas supply source 41 can supply nitrogen (N2) as a gas for removing foreign substances. However, the present disclosure is not necessarily limited thereto, and the first gas supply source 41 can also supply other gases, cleaning agents, etc.

[0053] The first gas supply line 42 can be formed between the electrostatic chuck 32 and the ring assembly 33. For example, the first gas supply line 42 can be formed to connect between the electrostatic chuck 32 and the focus ring 33a. Additionally, the first gas supply line 42 can be formed to be bent to connect between the electrostatic chuck 32 and the focus ring 33a by being disposed within the focus ring 33a.

[0054] The heating member 34 and the cooling member 35 can be configured such that when an etching process is performed in the processing space (A) of the processing chamber 20, the substrate (W) can be maintained at the process temperature. The heating member 34 can be provided as a heating wire for this use, and the cooling member 35 can be provided as a cooling path through which a coolant flows for this use.

[0055] The heating member 34 and the cooling member 35 can be installed within the substrate support 30 such that the substrate (W) can be maintained at the process temperature. For example, the heating member 34 can be installed within the electrostatic chuck 32, and the cooling member 35 can be installed within the base 31.

[0056] The device 100 for controlling plasma characteristics generates plasma (PM) from the gas remaining in the discharge space and can control the characteristics of the generated plasma (PM). In this case, the discharge space can refer to the space between the substrate support 30 and the showerhead 10 in the processing space (A) of the processing chamber 20.

[0057] The device 100 for controlling plasma characteristics can generate plasma (PM) in the discharge space in the processing space (A) of the processing chamber 20 using a capacitively coupled plasma (CCP) source. In this case, the device 100 for controlling plasma characteristics can use the showerhead 10 as a ground electrode (GE) and the electrostatic chuck 32 of the substrate support 30 as a power electrode (PE).

[0058] However, the configuration of the device 100 for controlling plasma characteristics is not necessarily limited thereto, and when generating plasma in the discharge space using an inductively coupled plasma (ICP) source, a separate antenna (not shown) installed in the upper part of the processing chamber 20 can be used as a ground electrode, and the electrostatic chuck 32 can be used as a power electrode, and it can be similarly applied when using microwaves (MW).

[0059] Meanwhile, in the processing space (A) of the processing chamber 100, the showerhead 10 serving as a ground electrode can be installed vertically facing the electrostatic chuck 32 serving as a power electrode. The showerhead 10 can be provided with a plurality of gas injection holes (H) for injecting a process gas into the processing space (A), and can be formed to have a diameter larger than that of the electrostatic chuck 32.

[0060] The second gas supply unit 60 supplies a process gas into the processing space (A) of the processing chamber 20 through the showerhead 10, and can include a second gas supply source 61 and a second gas supply pipeline 62.

[0061] More specifically, the second gas supply source 61 supplies an etching gas for processing the substrate (W) as the process gas, and can supply a gas containing a fluorine component (for example, a gas such as SF6 or CF4) as the etching gas.

[0062] In addition, the second gas supply source 61 can be provided as a single unit to supply the etching gas to the showerhead 10. However, the present disclosure is not necessarily limited thereto, and the second gas supply source 61 can also be provided as a plurality of second gas supply sources for supplying the process gas to the showerhead 10.

[0063] The gasket 70 is used to protect the inside of the processing chamber 20 from arc discharges generated during the process of exciting the process gas, impurities generated during the substrate processing process, and the like. The gasket 70 can be formed in a cylindrical shape with openings at the upper and lower parts along the inside of the processing chamber 20.

[0064] In addition, the gasket 70 can be provided with a support ring 71 on its upper part. The support ring 71 is formed to protrude outward (toward the outer surface of the processing chamber 20) from the upper part of the gasket 70, and can be placed at the upper end of the processing chamber 20 to support the gasket 70.

[0065] The baffle unit 80 can be used to discharge process by-products of the plasma, unreacted gases, and the like. The baffle unit 80 can be installed between the inner wall of the processing chamber 20 and the outer surface of the substrate support 30.

[0066] More specifically, the baffle unit 80 can be formed in an annular shape, and can be provided with a plurality of through holes penetrating the baffle unit 80 in the vertical direction (in the height direction of the processing chamber 20). The baffle unit 80 can control the flow of the process gas according to the number and shape of the through holes.

[0067] Hereinafter, the above-described apparatus 100 for controlling plasma characteristics will be described in detail.

[0068] The apparatus 100 for controlling plasma characteristics can include a power supply unit 110, a power processing unit 120, a measurement unit 130, and a control module 140.

[0069] Specifically, the power supply unit 110 may include a radio frequency (RF) power supply unit (RF) that applies a plasma generation voltage for generating plasma (PM) to the electrostatic chuck 32, and a non-sinusoidal generator (NSG) that applies a plasma control voltage for controlling the characteristics of the generated plasma (PM) to the electrostatic chuck 32. The plasma generation voltage and the plasma control voltage may be processed by the power processing unit 120 and then applied to the electrostatic chuck 32. The above-mentioned plasma generation voltage is a high-frequency AC voltage with a frequency of approximately 60 MHz, and the plasma control voltage may include a pulse voltage with a frequency of approximately 400 kHz.

[0070] The power processing unit 120 may perform impedance matching on the plasma generation voltage provided by the power supply unit 110, and then apply a plasma voltage obtained by adding the impedance-matched plasma generation voltage and the plasma control voltage to the electrostatic chuck 32. In the present disclosure, the plasma voltage may include at least one of a plasma generation voltage for generating plasma (PM) in the processing space (A) and a plasma control voltage for controlling the characteristics of the generated plasma (PM).

[0071] The measurement unit 130 may measure the voltage and current of the plasma voltage applied to the electrostatic chuck 32 by the power processing unit 120.

[0072] The control module 140 controls the power supply unit 110 to generate plasma (PM) in the processing space 10 of the processing chamber 20, and may control the characteristics of the generated plasma (PM). To this end, the control module 140 may include a control unit 141 and a storage unit 142.

[0073] In this case, the characteristics of the plasma (PM) may include at least one of a first sheath thickness (t sp ) from the substrate (W) to the plasma (PM) and a second sheath thickness (t sg ) from the showerhead 10 to the plasma (PM).

[0074] Specifically, the control unit 141 controls the power supply unit 110 to apply a plasma generation voltage to the electrostatic chuck 32 to generate plasma (PM) in the processing space 10, and after applying the plasma control voltage to the electrostatic chuck 32, an equivalent circuit seen from the non-sinusoidal generator (NSG) may be obtained.

[0075] Figures 2A to 2D An equivalent circuit according to an embodiment is shown. Figure 2A is composed of an equivalent resistance (R L ) and an equivalent capacitance (CL The R-C equivalent circuit composed of Figure 2B specifically shows Figure 2A the equivalent resistance (R L ) and equivalent capacitance (C L ), and Figure 2C and Figure 2D are the simplified versions of Figure 2B according to the polarity of the plasma control voltage.

[0076] First, as Figure 2A shown, the equivalent circuit seen from the non-sinusoidal generator (NSG) can be composed of an equivalent resistance (R L ) and an equivalent capacitance (C L ).

[0077] In this case, the equivalent resistance (R L ) can be approximated as the bulk resistance (R p ) of the plasma (PM) according to the following mathematical expression 1.

[0078] [Mathematical Expression 1]

[0079] R L ≒ R p

[0080] The equivalent capacitance (C L ) can be determined according to the following mathematical expression 2.

[0081] [Mathematical Expression 2]

[0082] C L = C st + C ch || (C p,sh + C g,sh )

[0083] In Mathematical Expression 2, C L can refer to the equivalent capacitance, C st can refer to the equivalent capacitance of the transmission pipeline and the processing chamber, C ch can refer to the capacitance of the dielectric provided on the upper surface of the electrostatic chuck, C p,sh can refer to the capacitance between the substrate and the plasma, and C g,sh can refer to the capacitance between the showerhead and the plasma. In this case, C st and C ch are base values that can be obtained in advance, and C p,sh or C g,sh can be omitted according to the polarity of the plasma control voltage (described later).

[0084] The above-mentioned equivalent capacitance (CL ) can be obtained through the following process.

[0085] First, the control unit 141 controls the power supply unit 110 so that a plasma generation voltage for generating plasma (PM) and a plasma control voltage for controlling the characteristics of the plasma (PM) can be applied to the electrostatic chuck 32 through the power processing unit 120.

[0086] The above-mentioned power processing unit 120 can apply a plasma voltage, which is the sum of the impedance-matched plasma generation voltage and the plasma control voltage, to the electrostatic chuck 32 after impedance-matching the plasma generation voltage provided by the power supply unit 110.

[0087] Subsequently, the control unit 141 uses the measurement unit 130 to measure the voltage and current of the voltage output from the power processing unit 120, and can obtain an equivalent circuit seen from the non-sinusoidal generator (NSG) based on the measured voltage and current.

[0088] Specifically, the control unit 141 can remove the components (voltage, current) generated by the RF power supply unit (RF) from the voltage and current.

[0089] To this end, the control unit 141 can perform a moving average or low-pass filtering on each of the voltage and current.

[0090] Thereafter, the control unit 141 can obtain a current value while changing the equivalent resistance (R L ) and the equivalent capacitance (C L ) respectively based on the voltage-current relationship shown in the following Mathematical Expression 3, and can estimate the resistance and capacitance as the equivalent resistance (R L ) and the equivalent capacitance (C L ) when the error between the obtained current value and the measured current value is less than a preset value.

[0091] [Mathematical Expression 3]

[0092]

[0093]

[0094] In Mathematical Expression 3, V(t) is the voltage, I(t) is the current, ω is the frequency, R L is the equivalent resistance, C L is the equivalent capacitance, and V’(t) can be the differential value of V(t).

[0095] The above-mentioned equivalent capacitance (C L), and the equivalent resistance (R L ), and its value can vary according to the polarity and amplitude of the plasma control voltage.

[0096] Meanwhile, Figures 3A to 3C is a graph showing the change of the first sheath thickness and the second sheath thickness according to the polarity and magnitude of the plasma control voltage in accordance with an embodiment.

[0097] Figure 3A is a state where only the plasma generation voltage is applied without applying the plasma control voltage, Figure 3B In (1) and (2) of, it shows that when the plasma control voltage has a (+) polarity and increases, the first sheath thickness (t sp ), and the second sheath thickness (t sg ), and Figure 3C In (1) and (2) of, it shows that when the plasma control voltage is (-) polarity and increases, the first sheath thickness (t sp ), and the second sheath thickness (t sg ). PE (power electrode) is the electrostatic chuck 32 (which is the power electrode to which the plasma voltage is applied), GE (ground electrode) is the showerhead 10 (which is the ground electrode), Vp is the plasma voltage, and the reference numeral 301 is the position indicating voltage.

[0098] As Figure 3B shown in (1) and (2) of, when the plasma control voltage has a (+) polarity and increases (see the reference numeral 310), as the plasma voltage (Vp) increases, the second sheath thickness (t sg ), increases, while the first sheath thickness (t sp ) decreases.

[0099] In this case, the first sheath thickness (t sp ) has a value that is smaller compared to Figure 3A , is almost constant in the (+) polarity, and is negligible compared to the second sheath thickness (t sg ). Therefore, among the equivalent capacitance (C L ), the capacitance (C sg ) related to the second sheath thickness (t g,sh ) can be regarded as 0, and thus can be omitted, as shown in the following mathematical expression 4.

[0100] [Mathematical Expression 4]

[0101]

[0102] In Mathematical Expression 4, C sh is the sheath capacitance, C p,shis the capacitance between the substrate and the plasma, C g,sh is the capacitance between the showerhead and the plasma, ε0 is the permittivity, A is the cross-sectional area of the electrostatic chuck, t sp is the first sheath thickness, and t sg can be the second sheath thickness.

[0103] Accordingly, the Figure 2B equivalent circuit can be represented as Figure 2C .

[0104] On the other hand, as shown in (1) and (2) of Figure 3C , when the plasma control voltage increases with a (-) polarity (see 320), as the plasma voltage (Vp) decreases, the first sheath thickness (t sp ) increases, while the second sheath thickness (t sg ) decreases.

[0105] In this case, the second sheath thickness (t sg ) has a value that is reduced compared to Figure 3A , is almost constant under a (-) polarity, and can be neglected compared to the first sheath thickness (t sp ). Therefore, the capacitance (C L ) among the equivalent capacitances (C sp ) related to the first sheath thickness (t p,sh ) can be regarded as 0, and thus can be omitted, as shown in the following mathematical expression 5.

[0106] [Mathematical Expression 5]

[0107]

[0108] In Mathematical Expression 5, C sh is the sheath capacitance, C p,sh is the capacitance between the substrate and the plasma, C g,sh is the capacitance between the showerhead and the plasma, ε0 is the permittivity, A is the cross-sectional area of the electrostatic chuck, t sp is the first sheath thickness, and t sg is the second sheath thickness.

[0109] Thereafter, the control unit 141 can increase the first sheath thickness (t sp ) by increasing the amplitude of the plasma control voltage with a (-) polarity, or can increase the second sheath thickness (t sg ) by increasing the amplitude of the plasma control voltage with a (+) polarity.

[0110] In this case, the first sheath thickness (tsp ).

[0111] [Mathematical Expression 6]

[0112]

[0113] In Mathematical Expression 6, t sp is the first sheath thickness, ε0 is the permittivity, A is the cross-sectional area of the electrostatic chuck, C L is the equivalent capacitance when the plasma control voltage has a (-) polarity, C st is the equivalent capacitance of the transfer line and the processing chamber, and C ch can be the capacitance of the dielectric provided on the upper surface of the electrostatic chuck.

[0114] In addition, the second sheath thickness (t sg ) can be determined according to the following Mathematical Expression 7.

[0115] [Mathematical Expression 7]

[0116]

[0117] In Mathematical Expression 7, t sg is the second sheath thickness, ε0 is the permittivity, A is the cross-sectional area of the electrostatic chuck, C L is the equivalent capacitance when the plasma control voltage has a (+) polarity, C st is the equivalent capacitance of the transfer line and the processing chamber, and C ch can be the capacitance of the dielectric provided on the upper surface of the electrostatic chuck.

[0118] Finally, the storage unit 142 can store various programs and data for implementing the functions executed in the control unit 141 above.

[0119] As described above, according to the embodiment, an equivalent circuit seen from a non-sinusoidal generator for applying a plasma control voltage to an electrostatic chuck provided in a processing space of a processing chamber is obtained, and by controlling the characteristics of the plasma generated in the processing space based on this equivalent circuit, a film formed on a substrate can be etched uniformly.

[0120] Meanwhile, Figure 4 is a flowchart showing a method for controlling plasma characteristics according to an embodiment. Figure 5 is to embody Figure 4 the operation S420 of

[0121] Refer to Figures 1 to 4, A method for controlling plasma characteristics according to an embodiment may start with: obtaining an operation of an equivalent circuit seen from a non-sinusoidal generator (NSG) that is used to apply a plasma control voltage to an electrostatic chuck 32 disposed in a processing space (A) of a processing chamber 20 (S410).

[0122] Specifically, as Figure 5 shown, when applying plasma power to the electrostatic chuck 32 through a power supply unit 110, a device 100 for controlling plasma characteristics may remove components (voltage and current) of RF power (RF) from the voltage and current output from the power supply unit 110 (S501). To this end, a moving average or low-pass filtering may be performed on each of the voltage and current.

[0123] As described above, the above plasma voltage may include at least one of a plasma generation voltage for generating plasma (PM) in the processing space (A) and a plasma control voltage for controlling the characteristics of the generated plasma (PM).

[0124] Thereafter, the device 100 for controlling plasma characteristics may differentiate the voltage V(t) (S502). The differentiated voltage V’(t) may be used in the above mathematical expression 3.

[0125] Thereafter, the device 100 for controlling plasma characteristics may estimate an equivalent resistance (R L ) and an equivalent capacitance (C L ) seen from the above-mentioned non-sinusoidal generator (NSG) of (+) polarity (S503).

[0126] Specifically, the initial values of the equivalent resistance (R L ) and the equivalent capacitance (C L ) may be set to arbitrary values, and the device 100 for controlling plasma characteristics applies the initial values of the equivalent resistance (R L ) and the equivalent capacitance (C L ) set to arbitrary values to the voltage-current relationship shown in the above mathematical expression 3 to obtain a current value I(t), and may determine whether the absolute value error between the obtained I(t) and the measured current value I f (t) is less than a preset value (δ) (S504). It should be noted that the above preset value (δ) may be appropriately set according to the needs of those skilled in the art and is not limited to a specific numerical value.

[0127] As a determination result in S504, if the absolute value error between the obtained I(t) and the measured current value I f (t) is the preset value (δ) or greater, the equivalent resistance (RL ) and equivalent capacitance (C L ). After that, based on the voltage-current relationship shown in the above mathematical expression 3, the current value I(t) is obtained again, and it is possible to determine whether the absolute error between the obtained I(t) and the previously measured current value I f (t) is less than a preset value (δ). If the error is less than the preset value (δ), the value at this time can be estimated as the equivalent resistance (R L ) and equivalent capacitance (C L ).

[0128] Next, the equivalent resistance (R L,comp ) and equivalent capacitance (C L,comp ) seen from the non-sinusoidal generator (NSG) with a (-) polarity can be estimated (S505).

[0129] As described above, the initial values of the equivalent resistance (R L,comp ) and equivalent capacitance (C L,comp ) can be set to arbitrary values. After that, the device 100 for controlling plasma characteristics applies the initial values of the equivalent resistance (R L,comp ) and equivalent capacitance (C L,comp ) set to arbitrary values to the voltage-current relationship shown in the above mathematical expression 3 to obtain the current value I(t), and it is possible to determine whether the absolute error between the obtained I(t) and the measured current value I f (t) is less than a preset value (δ) (S506).

[0130] As a result of the determination in S506, if the absolute error between the obtained I(t) and the measured current value I f (t) is equal to or greater than the preset value (δ), the values of the equivalent resistance (R L,comp ) and equivalent capacitance (C L,comp ) are changed respectively. After that, based on the voltage-current relationship shown in the above mathematical expression 3, the current value I(t) is obtained again, and it is possible to determine whether the absolute error between the obtained I(t) and the previously measured current value I f (t) is less than a preset value (δ) (S506). If the error is less than the preset value (δ), the value at this time can be estimated as the equivalent resistance (R L,comp ) and equivalent capacitance (C L,comp ).

[0131] As described above, the above equivalent circuit is an R-C equivalent circuit composed of an equivalent resistance (R L ) and an equivalent capacitance (C L ).

[0132] In addition, as described above, the equivalent capacitance (CL It can have a value that varies according to the polarity and amplitude of the plasma control voltage.

[0133] Referring again to Figure 4 , the device 100 for controlling plasma characteristics can control the characteristics of the plasma generated in the processing space based on the equivalent circuit obtained above (S420).

[0134] In this case, as described above, the characteristics of the plasma (PM) can include the first sheath thickness (t from the substrate (W) to the plasma (PM) sp ) and at least one of the second sheath thickness (t from the showerhead 10 to the plasma (PM). sg )

[0135] In addition, the first sheath thickness (t sp ) can have a value that increases as the amplitude of the plasma control voltage with a (-) polarity increases, and the second sheath thickness (t sg ) can have a value that increases as the amplitude of the plasma control voltage with a (+) polarity increases.

[0136] Therefore, as described above, the device 100 for controlling plasma characteristics can increase the first sheath thickness (t sp ) by increasing the amplitude of the plasma control voltage with a (-) polarity, or can increase the second sheath thickness (t sg ) by increasing the amplitude of the plasma control voltage with a (+) polarity.

[0137] As described above, according to an embodiment, an equivalent circuit seen from a non-sinusoidal generator for applying a plasma control voltage to an electrostatic chuck provided in a processing space of a processing chamber is obtained, and by controlling the characteristics of the plasma generated in the processing space based on this equivalent circuit, a film formed on a substrate can be etched uniformly.

[0138] Figure 6 is a block diagram of a computing device according to an embodiment, and the computing device can fully or partially implement the control unit 141 of the device for controlling plasma characteristics.

[0139] As Figure 6 shown, the computing device 600 includes at least one processor 601, a computer-readable storage medium 602, and a communication bus 603.

[0140] The processor 601 can enable the computing device 600 to operate according to the above exemplary embodiments. For example, the processor 601 can execute one or more programs stored in the computer-readable storage medium 602. The one or more programs can include one or more computer-executable instructions, and when executed by the processor 601, the computer-executable instructions can be configured to cause the computing device 600 to perform operations according to the exemplary embodiments.

[0141] The computer-readable storage medium 602 is configured to store computer-executable instructions or program code, program data, and / or other suitable forms of information. The program 602a stored in the computer-readable storage medium 602 includes a set of instructions executable by the processor 601. In an embodiment, the computer-readable storage medium 602 can be a memory (such as a volatile memory like a random access memory, a non-volatile memory, or a suitable combination thereof), one or more disk storage devices, optical disk storage devices, flash memory devices, other forms of storage media that can be accessed by the computing device 600 and store the required information, or a suitable combination thereof.

[0142] The communication bus 603 interconnects various other components of the computing device 600, including the processor 601 and the computer-readable storage medium 602.

[0143] The computing device 600 may further include one or more network communication interfaces 606 and one or more input / output interfaces 605 for providing an interface for one or more input / output devices 604. The input / output interface 605 and the network communication interface 606 are connected to the communication bus 603. The network can be any of the cellular networks, for example, Global System for Mobile Communications (GSM), Enhanced Data Rates for GSM Evolution (EDGE), General Packet Radio Service (GPRS), Code Division Multiple Access (CDMA), Time Division CDMA (TD-CDMA), Universal Mobile Telecommunications System (UMTS), Long Term Evolution (LTE), or other cellular networks.

[0144] The input / output device 604 can be connected to other components of the computing device 600 through the input / output interface 605. As an example, the input / output device 604 can include input devices (such as pointing devices (e.g., mouse, touchpad, etc.), keyboards, touch input devices (e.g., touchpad, touch screen, etc.), voice or audio input devices, various types of sensor devices, and / or imaging devices), and / or output devices (such as display devices, printers, speakers, and / or network cards). Exemplary input / output devices 604 can be included within the computing device 600 as components constituting the computing device 600, or can be connected to the computing device 600 as separate devices different from the computing device 600.

[0145] On the other hand, embodiments of the present disclosure may include a program for executing the methods described in this specification on a computer, and a computer-readable recording medium containing the program. The computer-readable recording medium may include program instructions, local data files, local data structures, etc. individually or in combination. Such a medium may be a medium specifically designed and constructed for the present disclosure, or may be a medium common in the field of computer software. Examples of computer-readable recording media include magnetic media (e.g., hard disks, floppy disks, and magnetic tapes), optical recording media (e.g., CD-ROMs and DVDs), and hardware devices specifically configured to store and execute program instructions (e.g., ROM, RAM, flash memory, etc.). Examples of programs may include not only machine language code (e.g., code generated by a compiler), but also high-level language code that can be executed by a computer using an interpreter, etc.

[0146] As described above, according to an embodiment, the temperature ripple of the power module can be estimated based on the ripple of the maximum conduction loss generated due to the conduction of the power module when the low-speed drive motor is operating, and the change in the junction temperature of the power module when the high-speed drive motor is operating and the temperature of the coolant used to cool the power module can be added to the estimated temperature ripple to estimate the junction temperature of the power module, thereby accurately estimating the junction temperature of the power module when the low-speed drive motor is operating.

[0147] As described above, according to an embodiment, an equivalent circuit seen from a non-sinusoidal generator for applying a plasma control voltage to an electrostatic chuck disposed in a processing space of a processing chamber can be obtained, and by controlling the characteristics of the plasma generated in the processing space based on the equivalent circuit, a film formed on a substrate can be etched uniformly.

[0148] Although example embodiments have been shown and described above, it will be apparent to those skilled in the art that modifications and changes can be made without departing from the scope of the present disclosure defined by the appended claims.

Claims

1. An apparatus for controlling plasma characteristics, comprising: one or more processors; as well as A storage medium storing computer readable instructions, Wherein, when executed by the one or more processors, the computer readable instructions are configured to cause the one or more processors to: obtaining an equivalent circuit as seen from a non-sinusoidal generator for applying a plasma control voltage to an electrostatic chuck disposed in a process space of a process chamber, and controlling the characteristics of the plasma generated in the processing space based on the obtained equivalent circuit, The characteristics of the plasma include: the first sheath thickness t from the substrate to the plasma sp , and a second sheath thickness t from a nozzle that injects process gas into the processing space to the plasma sg at least one of .

2. The device according to claim 1, wherein: The one or more processors remove a component generated by an RF power supply unit from a voltage and a current output by a power supply unit that applies a voltage to the electrostatic chuck, the power supply unit comprising: the RF power supply unit that applies a plasma generation voltage for generating the plasma, and a non-sinusoidal generator that applies a plasma control voltage for controlling a characteristic of the generated plasma, and The one or more processors obtain the equivalent circuit seen from the non-sinusoidal generator based on voltages and currents from which components generated by the RF power supply unit have been removed.

3. The device according to claim 1, wherein: The equivalent circuit is an RC equivalent circuit composed of an equivalent resistor and an equivalent capacitor.

4. The device according to claim 3, wherein: The one or more processors estimate the resistance and capacitance as the equivalent resistance and the equivalent capacitance when an error between a measured current value and a current value obtained by respectively changing the equivalent resistance and the equivalent capacitance based on a voltage-current relationship is less than a preset value.

5. The device according to claim 4, wherein: The voltage-current relationship is determined by the following mathematical expression: ， Wherein, I(t) is the current from which the component generated by the RF power supply unit is removed, V(t) is the voltage from which the component generated by the RF power supply unit is removed, ω is the frequency, R L is the equivalent resistance, C L is the equivalent capacitance, and V'(t) is the differential value of V(t).

6. The device according to claim 4, wherein: The equivalent capacitance and the equivalent resistance are estimated for each of the (+) polarity and the (−) polarity of the plasma control voltage.

7. The device according to claim 2, wherein: The one or more processors perform low pass filtering or a moving average on each of the measured voltage and the measured current.

8. The device according to claim 2, wherein: The voltage applied from the power supply unit is a voltage obtained by performing impedance matching on the plasma generation voltage and then adding the impedance-matched plasma generation voltage to the plasma control voltage.

9. The device according to claim 3, wherein: The equivalent capacitance has a value that varies according to the polarity and magnitude of the plasma control voltage.

10. The device according to claim 1, wherein: The first sheath thickness has a value that increases with an increase in the magnitude of the plasma control voltage having a (-) polarity, and The second sheath thickness has a value that increases with an increase in the magnitude of the plasma control voltage having a (+) polarity.

11. The device according to claim 1, wherein: The one or more processors increase the first sheath thickness by increasing the magnitude of the plasma control voltage of (-) polarity, or The one or more processors increase the second sheath thickness by increasing the magnitude of the plasma control voltage of (+) polarity.

12. The device according to claim 1, wherein: The first sheath thickness t sp Determined according to the following mathematical expression: ， Among them, t sp is the thickness of the first sheath layer, ε0 is the dielectric constant, A is the cross-sectional area of ​​the electrostatic chuck, C L is the equivalent capacitance when the plasma control voltage has a (-) polarity, C st is the equivalent capacitance of the transfer line and the process chamber, and C ch is the capacitance of a dielectric disposed on the upper surface of the electrostatic chuck.

13. The apparatus according to claim 1, wherein: The thickness of the second sheath layer is determined according to the following mathematical expression: ， Among them, t sg is the thickness of the second sheath layer, ε0 is the dielectric constant, A is the cross-sectional area of ​​the electrostatic chuck, C L is the equivalent capacitance when the plasma control voltage has a (+) polarity, C st is the equivalent capacitance of the process chamber, and C ch is the capacitance of a dielectric disposed on the upper surface of the electrostatic chuck.

14. The apparatus according to claim 3, wherein: The equivalent capacitance is determined according to the following mathematical expression: C L =C st +C ch || (C p,sh + C g,sh ), Among them, C L is the equivalent capacitance, C st is the equivalent capacitance of the transfer line and the process chamber, C ch is the capacitance of the dielectric disposed on the upper surface of the electrostatic chuck, C p,sh is the capacitance between the plasma and the substrate, and C g,sh is the capacitance between the plasma in the showerhead.

15. The device according to claim 14, wherein: When the polarity of the plasma control voltage is (+), the C p,sh is 0, and When the polarity of the plasma control voltage is (-), the C g,sh is 0.

16. The apparatus according to claim 3, wherein: The equivalent resistance is determined according to the following mathematical expression: R L ≒R p , Among them, R L is the equivalent resistance, and R p is the resistance of the bulk plasma.

17. The apparatus according to claim 1, wherein: The plasma control voltage is a pulse voltage.

18. A method of controlling plasma characteristics, comprising: A first operation for obtaining an equivalent circuit as seen from a non-sinusoidal generator for applying a plasma control voltage to an electrostatic chuck disposed in a process space of a process chamber; as well as a second operation for controlling the characteristics of the plasma generated in the processing space based on the obtained equivalent circuit, The characteristic of the plasma includes at least one of the following: a first sheath thickness from a substrate to the plasma, and a second sheath thickness from a showerhead that sprays a process gas into the processing space to the plasma.

19. The method according to claim 18, wherein: The second operation increases the first sheath thickness t by increasing the amplitude of the plasma control voltage of (-) polarity. sp , or by increasing the amplitude of the plasma control voltage of (+) polarity to increase the thickness t of the second sheath sg .

20. A system for processing a substrate, comprising: a processing chamber having a processing space in which the substrate can be processed; a shower head installed in an upper portion of the processing space in the processing chamber and spraying a process gas for processing the substrate into the processing space; an electrostatic chuck installed at a lower side of the processing space in the processing chamber to vertically face the shower head and provided with the substrate mounted thereon; as well as A plasma property control device for controlling the properties of a plasma based on an equivalent circuit, Wherein, the plasma characteristic control device comprises: a power supply unit for applying a voltage to the electrostatic chuck, the power supply unit comprising: an RF power supply unit for applying a plasma generation voltage for generating the plasma, and a non-sinusoidal generator for applying a plasma control voltage for controlling a characteristic of the generated plasma; a measuring unit for measuring a voltage and a current output from the power supply unit; and a control unit for removing a component generated by the RF power supply unit from the voltage and current measured by the measuring unit, obtaining an equivalent circuit seen from the non-sinusoidal generator based on the voltage and current from which the component generated by the RF power supply unit has been removed, and then controlling the characteristics of the plasma based on the obtained equivalent circuit, The characteristics of the plasma include at least one of: a first sheath thickness from the substrate to the plasma, and a second sheath thickness from a nozzle for injecting process gas into the processing space to the plasma, and The control unit increases the first sheath thickness t by increasing the amplitude of the plasma control voltage of (-) polarity. sp , or by increasing the amplitude of the plasma control voltage of (+) polarity to increase the thickness t of the second sheath sg .

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