KR101736847B1 - Plasma generation device, method for adjusting phase difference, and apparatus for processing substrate employing the same - Google Patents

Abstract

The present invention relates to a plasma generating apparatus, a phase difference adjusting method, and a substrate processing apparatus using the same. A plasma generator according to an embodiment of the present invention includes: a first RF power supply for supplying a first RF signal; A first plasma source for generating plasma by receiving the first RF signal; A second RF power supply for supplying a second RF signal; A second plasma source for generating a plasma by receiving the second RF signal; A sensing unit provided at an input terminal of the second plasma source to sense a parameter of the second RF signal; And a controller for measuring an impedance of the plasma using the sensed parameter and adjusting a phase difference between the first RF signal and the second RF signal based on the measured impedance.

Description

TECHNICAL FIELD [0001] The present invention relates to a plasma generating apparatus, a phase difference adjusting method, and a substrate processing apparatus using the same. BACKGROUND ART [0002]

The present invention relates to a plasma generating apparatus, a phase difference adjusting method, and a substrate processing apparatus using the same.

A process for depositing or etching a thin film on a substrate using a plasma in a semiconductor process is widely used. In particular, the technique of generating plasma in a chamber using two or more RF signals generates plasma using a part of an RF signal while controlling characteristics of the plasma such as ion flux by using another RF signal, thereby more effectively discharging the plasma, .

In the plasma process using the plurality of RF signals, although the intensity and the frequency of the RF signals are important, the phase difference between them may affect the plasma discharge characteristics and the process rate (deposition rate, etch rate, etc.) in the chamber. However, the conventional substrate processing apparatus does not introduce a process of setting a value optimized for the equipment in order to control the phase difference between the RF signals or to improve the productivity of the process.

Embodiments of the present invention provide a plasma generating apparatus, a phase difference adjusting method, and a substrate processing apparatus capable of improving the productivity of a substrate processing process by appropriately adjusting a phase difference between a plurality of RF signals for a plasma process .

A plasma generator according to an embodiment of the present invention includes: a first RF power supply for supplying a first RF signal; A first plasma source for generating plasma by receiving the first RF signal; A second RF power supply for supplying a second RF signal; A second plasma source for generating a plasma by receiving the second RF signal; A sensing unit provided at an input terminal of the second plasma source to sense a parameter of the second RF signal; And a controller for measuring an impedance of the plasma using the sensed parameter and adjusting a phase difference between the first RF signal and the second RF signal based on the measured impedance.

The frequency of the first RF signal may be higher than or equal to the frequency of the second RF signal.

The frequency of the first RF signal is n times the frequency of the second RF signal, where n may be a real number greater than or equal to one.

The first plasma source may include an upper electrode among parallel plate electrodes disposed in a plasma chamber, and the second plasma source may include a lower electrode among the parallel plate electrodes.

The sensing unit may include: a sensor for sensing a voltage and a current of the second RF signal.

The plasma generator includes a first impedance matcher provided between the first RF power source and the first plasma source to match an output impedance of the first RF power source with an input impedance of the first plasma source; And a second impedance matcher provided between the second RF power source and the second plasma source for matching the output impedance of the second RF power source with the input impedance of the second plasma source.

Wherein the controller is configured to: match the phase of the first RF signal with the phase of the second RF signal, measure the impedance while changing the phase difference between the first RF signal and the second RF signal, Obtaining a first set of impedances for said impedances associated with said set of phase differences and said phase differences and determining an extremum of said function indicative of said impedances for said phase differences based on said first set of phase differences and said first set of impedances, And to control at least one of the first RF power source and the second RF power source so that a phase difference between the first RF signal and the second RF signal is the target phase difference.

Wherein the controller is configured to: match the phase of the first RF signal with the phase of the second RF signal, measure the impedance while changing the phase difference between the first RF signal and the second RF signal, Obtaining a first set of impedances for the impedance associated with the phase difference set and the corresponding phase difference, calculating an average and standard deviation of the impedances from the first set of impedances, and calculating an average and a standard deviation of the impedances belonging to the first set of impedances, And the phase difference corresponding to the impedance is determined as the starting impedance and the starting phase difference, and the phase difference between the first RF signal and the second RF signal is determined as the starting phase Controls at least one of the first RF power source and the second RF power source so that the first R F signal and the second RF signal while measuring the impedance to obtain a second phase difference set for the phase difference and a second impedance set for the impedance related to the phase difference, Obtaining a target phase difference representing an extremum and the extremum of a function indicative of the impedance for the phase difference based on the set of phase differences and the second impedance set and determining a phase difference between the first RF signal and the second RF signal, And at least one of the first RF power source and the second RF power source may be controlled to have the target phase difference.

The acquisition of the first set of phase differences and the first set of impedances may be repeated until the phase difference between the first RF signal and the second RF signal is greater than or equal to 180 °.

The acquisition of the second phase difference set and the second impedance set is repeated by changing the phase difference between the first RF signal and the second RF signal until the measured impedance deviates from the average out of the standard deviation .

According to an aspect of the present invention, there is provided a method of adjusting a phase difference, comprising: supplying a first RF signal and a second RF signal from a first RF power source and a second RF power source to a first plasma source and a second plasma source, respectively; Sensing a parameter of the second RF signal supplied to the second plasma source; And adjusting a phase difference between the first RF signal and the second RF signal based on the impedance of the plasma measured using the sensed parameter.

The frequency of the first RF signal may be higher than or equal to the frequency of the second RF signal.

The frequency of the first RF signal is n times the frequency of the second RF signal, where n may be a real number greater than or equal to one.

The first plasma source may include an upper electrode among parallel plate electrodes disposed in a plasma chamber, and the second plasma source may include a lower electrode among the parallel plate electrodes.

The sensing the parameter of the second RF signal may include: sensing the voltage and current of the second RF signal.

Wherein adjusting the phase difference comprises: phase matching the first RF signal and the second RF signal; Measuring the impedance while changing the phase difference between the first RF signal and the second RF signal to obtain a first phase difference set for the phase difference and a first impedance set for the impedance related to the phase difference, ; Obtaining a target phase difference representing an extremum of the function and the extremum representing the impedance for the phase difference based on the first set of phase differences and the first set of impedances; And controlling at least one of the first RF power source and the second RF power source such that a phase difference between the first RF signal and the second RF signal is the target phase difference.

Wherein adjusting the phase difference comprises: phase matching the first RF signal and the second RF signal; Measuring the impedance while changing the phase difference between the first RF signal and the second RF signal to obtain a first phase difference set for the phase difference and a first impedance set for the impedance related to the phase difference, ; Calculating an average and standard deviation of the impedance from the first set of impedances; Determining one of the impedances distributed within the standard deviation from the average among the impedances belonging to the first impedance set and the phase difference corresponding to the impedance as the starting impedance and the starting phase difference, respectively; Controlling at least one of the first RF power source and the second RF power source such that a phase difference between the first RF signal and the second RF signal is the starting phase difference; Measuring the impedance while changing the phase difference between the first RF signal and the second RF signal to obtain a second phase difference set for the phase difference and a second impedance set for the impedance related to the phase difference, ; Obtaining a target phase difference representing an extremum and the extremum of the function indicative of the impedance for the phase difference based on the second set of phase differences and the second set of impedances; And controlling at least one of the first RF power source and the second RF power source such that a phase difference between the first RF signal and the second RF signal is the target phase difference.

Obtaining the first set of phase differences and the first set of impedances may be performed iteratively until the phase difference between the first RF signal and the second RF signal is greater than or equal to 180 °.

Wherein the obtaining of the second set of phase differences and the second set of impedances comprises: when the measured impedance is changed by shifting the phase difference between the first RF signal and the second RF signal out of the range of the standard deviation Can be repeatedly performed.

A substrate processing apparatus according to an embodiment of the present invention includes a chamber for providing a space in which a substrate is processed; A substrate support assembly for supporting the substrate within the chamber; A gas supply unit for supplying gas into the chamber; And a plasma generating unit that excites gas in the chamber into a plasma state, the plasma generating unit comprising: a first RF power supply for supplying a first RF signal; A first plasma source for generating plasma by receiving the first RF signal; A second RF power supply for supplying a second RF signal; A second plasma source for generating a plasma by receiving the second RF signal; A sensing unit provided at an input terminal of the second plasma source to sense a parameter of the second RF signal; And a controller for measuring an impedance of the plasma using the sensed parameter and adjusting a phase difference between the first RF signal and the second RF signal based on the measured impedance.

According to the embodiment of the present invention, the productivity of the substrate processing process can be improved by appropriately adjusting the phase difference between a plurality of RF signals for the plasma process.

1 is an exemplary diagram showing a substrate processing apparatus according to an embodiment of the present invention.
2 is an exemplary diagram schematically showing a plasma generating apparatus according to an embodiment of the present invention.
3 is an exemplary diagram illustrating waveforms and phase differences of first and second RF signals in accordance with an embodiment of the present invention.
FIG. 4 is a graph showing the coordinates of the phase difference between the first and second RF signals and the corresponding impedance in a two-dimensional coordinate plane according to an embodiment of the present invention. Referring to FIG.
5 is an exemplary distribution diagram derived based on the mean and standard deviation of the impedance in accordance with another embodiment of the present invention.
FIG. 6 is a graph showing a coordinate on a two-dimensional coordinate plane, which is composed of a phase difference between first and second RF signals and a corresponding impedance according to another embodiment of the present invention.
7 is an exemplary flowchart of a phase difference adjustment method according to an embodiment of the present invention.
8 is an exemplary flowchart illustrating a process of adjusting the phase difference between the first and second RF signals according to an embodiment of the present invention.
9 is an exemplary flow chart illustrating the process of adjusting the phase difference between the first and second RF signals in accordance with another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings attached hereto.

1 is an exemplary diagram showing a substrate processing apparatus 10 according to an embodiment of the present invention.

Referring to Fig. 1, a substrate processing apparatus 10 processes a substrate W using a plasma. For example, the substrate processing apparatus 10 may perform an etching process on the substrate W. [ The substrate processing apparatus 10 may include a chamber 100, a substrate support assembly 200, a showerhead 300, a gas supply unit 400, a baffle unit 500, and a plasma generation unit.

The chamber 100 may provide a processing space in which a substrate processing process is performed. The chamber 100 may have a processing space therein and may be provided in a closed configuration. The chamber 100 may be made of a metal material. The chamber 100 may be made of aluminum. The chamber 100 may be grounded. An exhaust hole 102 may be formed in the bottom surface of the chamber 100. The exhaust hole 102 may be connected to the exhaust line 151. The reaction byproducts generated in the process and the gas staying in the inner space of the chamber can be discharged to the outside through the exhaust line 151. The interior of the chamber 100 may be depressurized to a predetermined pressure by an evacuation process.

According to one example, a liner 130 may be provided within the chamber 100. The liner 130 may have a cylindrical shape with open top and bottom surfaces. The liner 130 may be provided to contact the inner surface of the chamber 100. The liner 130 protects the inner wall of the chamber 100 to prevent the inner wall of the chamber 100 from being damaged by the arc discharge. It is also possible to prevent impurities generated during the substrate processing step from being deposited on the inner wall of the chamber 100. Optionally, the liner 130 may not be provided.

The substrate support assembly 200 may be located within the chamber 100. The substrate support assembly 200 can support the substrate W. [ The substrate support assembly 200 may include an electrostatic chuck 210 for attracting a substrate W using an electrostatic force. Alternatively, the substrate support assembly 200 may support the substrate W in a variety of ways, such as mechanical clamping. Hereinafter, the substrate support assembly 200 including the electrostatic chuck 210 will be described.

The substrate support assembly 200 may include an electrostatic chuck 210, a bottom cover 250 and a plate 270. The substrate support assembly 200 may be spaced upwardly from the bottom surface of the chamber 100 within the chamber 100.

The electrostatic chuck 210 may include a dielectric plate 220, a body 230, and a focus ring 240. The electrostatic chuck 210 can support the substrate W. [

The dielectric plate 220 may be positioned at the top of the electrostatic chuck 210. The dielectric plate 220 may be provided as a disk-shaped dielectric substance. The substrate W may be placed on the upper surface of the dielectric plate 220. The upper surface of the dielectric plate 220 may have a smaller radius than the substrate W. [ Therefore, the edge region of the substrate W may be located outside the dielectric plate 220.

The dielectric plate 220 may include a first electrode 223, a heater 225, and a first supply path 221 therein. The first supply passage 221 may be provided from the upper surface to the lower surface of the dielectric plate 210. A plurality of first supply passages 221 may be provided spaced apart from each other and may be provided as a passage through which the heat transfer medium is supplied to the bottom surface of the substrate W.

The first electrode 223 may be electrically connected to the first power source 223a. The first power source 223a may include a DC power source. A switch 223b may be provided between the first electrode 223 and the first power source 223a. The first electrode 223 may be electrically connected to the first power source 223a by turning on / off the switch 223b. When the switch 223b is turned on, a direct current can be applied to the first electrode 223. An electrostatic force acts between the first electrode 223 and the substrate W by the current applied to the first electrode 223 and the substrate W can be attracted to the dielectric plate 220 by the electrostatic force.

The heater 225 may be positioned below the first electrode 223. The heater 225 may be electrically connected to the second power source 225a. The heater 225 can generate heat by resisting the current applied from the second power source 225a. The generated heat can be transferred to the substrate W through the dielectric plate 220. The substrate W can be maintained at a predetermined temperature by the heat generated in the heater 225. The heater 225 may include a helical coil.

The body 230 may be positioned below the dielectric plate 220. The bottom surface of the dielectric plate 220 and the top surface of the body 230 may be adhered by an adhesive 236. The body 230 may be made of aluminum. The upper surface of the body 230 may be stepped so that the central region is located higher than the edge region. The top center region of the body 230 has an area corresponding to the bottom surface of the dielectric plate 220 and can be adhered to the bottom surface of the dielectric plate 220. The body 230 may have a first circulation channel 231, a second circulation channel 232, and a second supply channel 233 formed therein.

The first circulation channel 231 may be provided as a passage through which the heat transfer medium circulates. The first circulation flow path 231 may be formed in a spiral shape inside the body 230. Alternatively, the first circulation flow path 231 may be arranged so that the ring-shaped flow paths having different radii have the same center. Each of the first circulation flow paths 231 can communicate with each other. The first circulation flow paths 231 may be formed at the same height.

The second circulation flow passage 232 may be provided as a passage through which the cooling fluid circulates. The second circulation flow path 232 may be formed in a spiral shape inside the body 230. Alternatively, the second circulation flow path 232 may be arranged so that the ring-shaped flow paths having different radii have the same center. And each of the second circulation flow paths 232 can communicate with each other. The second circulation channel 232 may have a larger cross-sectional area than the first circulation channel 231. The second circulation flow paths 232 may be formed at the same height. The second circulation flow passage 232 may be positioned below the first circulation flow passage 231.

The second supply passage 233 extends upward from the first circulation passage 231 and may be provided on the upper surface of the body 230. The second supply passage 243 is provided in a number corresponding to the first supply passage 221 and can connect the first circulation passage 231 and the first supply passage 221.

The first circulation channel 231 may be connected to the heat transfer medium storage unit 231a through the heat transfer medium supply line 231b. The heat transfer medium storage unit 231a may store the heat transfer medium. The heat transfer medium may include an inert gas. According to an embodiment, the heat transfer medium may comprise helium (He) gas. The helium gas may be supplied to the first circulation channel 231 through the supply line 231b and may be supplied to the bottom surface of the substrate W sequentially through the second supply channel 233 and the first supply channel 221 . The helium gas may act as a medium through which heat transferred from the plasma to the substrate W is transferred to the electrostatic chuck 210.

The second circulation channel 232 may be connected to the cooling fluid storage 232a through the cooling fluid supply line 232c. The cooling fluid may be stored in the cooling fluid storage portion 232a. A cooler 232b may be provided in the cooling fluid storage portion 232a. The cooler 232b may cool the cooling fluid to a predetermined temperature. Alternatively, the cooler 232b may be installed on the cooling fluid supply line 232c. The cooling fluid supplied to the second circulation channel 232 through the cooling fluid supply line 232c circulates along the second circulation channel 232 and can cool the body 230. [ The body 230 is cooled and the dielectric plate 220 and the substrate W are cooled together to maintain the substrate W at a predetermined temperature.

The body 230 may include a metal plate. According to one example, the entire body 230 may be provided as a metal plate. The body 230 may be electrically connected to the third power source 235a. The third power source 235a may be provided as a high frequency power source for generating high frequency power. The high frequency power source may include an RF power source. The body 230 can receive high frequency power from the third power source 235a. This allows the body 230 to function as an electrode.

The focus ring 240 may be disposed at the edge region of the electrostatic chuck 210. The focus ring 240 has a ring shape and may be disposed along the periphery of the dielectric plate 220. The upper surface of the focus ring 240 may be stepped so that the outer portion 240a is higher than the inner portion 240b. The upper surface inner side portion 240b of the focus ring 240 may be positioned at the same height as the upper surface of the dielectric plate 220. [ The upper surface inner side portion 240b of the focus ring 240 can support the edge region of the substrate W positioned outside the dielectric plate 220. [ The outer side portion 240a of the focus ring 240 may be provided so as to surround the edge region of the substrate W. [ The focus ring 240 can control the electromagnetic field so that the density of the plasma is evenly distributed over the entire area of the substrate W. [ Thereby, plasma is uniformly formed over the entire region of the substrate W, so that each region of the substrate W can be uniformly etched.

The lower cover 250 may be located at the lower end of the substrate support assembly 200. The lower cover 250 may be spaced upwardly from the bottom surface of the chamber 100. The lower cover 250 may have a space 255 in which the upper surface thereof is opened. The outer radius of the lower cover 250 may be provided with a length equal to the outer radius of the body 230. A lift pin module (not shown) for moving the substrate W to be transferred from an external carrying member to the electrostatic chuck 210 may be positioned in the inner space 255 of the lower cover 250. The lift pin module (not shown) may be spaced apart from the lower cover 250 by a predetermined distance. The bottom surface of the lower cover 250 may be made of a metal material. The inner space 255 of the lower cover 250 may be provided with air. Air may have a lower dielectric constant than the insulator and may serve to reduce the electromagnetic field inside the substrate support assembly 200.

The lower cover 250 may have a connecting member 253. The connecting member 253 can connect the outer surface of the lower cover 250 and the inner wall of the chamber 100. A plurality of connecting members 253 may be provided on the outer surface of the lower cover 250 at regular intervals. The connection member 253 can support the substrate support assembly 200 inside the chamber 100. The connection member 253 may be connected to the inner wall of the chamber 100 so that the lower cover 250 is electrically grounded. A first power supply line 223c connected to the first power supply 223a, a second power supply line 225c connected to the second power supply 225a, a third power supply line 235c connected to the third power supply 235a, A heat transfer medium supply line 231b connected to the heat transfer medium storage part 231a and a cooling fluid supply line 232c connected to the cooling fluid storage part 232a are connected to each other through the internal space 255 of the connection member 253, And may extend into the cover 250.

A plate 270 may be positioned between the electrostatic chuck 210 and the lower cover 250. The plate 270 may cover the upper surface of the lower cover 250. The plate 270 may be provided with a cross-sectional area corresponding to the body 230. The plate 270 may comprise an insulator. According to one example, one or a plurality of plates 270 may be provided. The plate 270 may serve to increase the electrical distance between the body 230 and the lower cover 250.

The showerhead 300 may be located above the substrate support assembly 200 within the chamber 100. The showerhead 300 may be positioned to face the substrate support assembly 200.

The showerhead 300 may include a gas distributor 310 and a support 330. The gas distribution plate 310 may be spaced apart from the upper surface of the chamber 100 by a predetermined distance. A predetermined space may be formed between the upper surface of the gas distribution plate 310 and the chamber 100. The gas distribution plate 310 may be provided in a plate shape having a constant thickness. The bottom surface of the gas distribution plate 310 may be polarized on its surface to prevent arcing by plasma. The cross-section of the gas distribution plate 310 may be provided to have the same shape and cross-sectional area as the substrate support assembly 200. The gas distribution plate 310 may include a plurality of ejection holes 311. The injection hole 311 can penetrate the upper and lower surfaces of the gas distribution plate 310 in the vertical direction. The gas distribution plate 310 may include a metal material. The gas distributor 310 may be electrically connected to the fourth power source 351. The fourth power source 351 may be provided as a high frequency power source. Alternatively, the gas distribution plate 310 may be electrically grounded. The gas distributor plate 310 may be electrically connected to the fourth power source 351 or may be grounded to function as an electrode.

The support portion 330 can support the side of the gas distributor plate 310. The support portion 330 may have an upper end connected to the upper surface of the chamber 100 and a lower end connected to the side of the gas distribution plate 310. The support portion 330 may include a non-metallic material.

The gas supply unit 400 can supply the process gas into the chamber 100. The gas supply unit 400 may include a gas supply nozzle 410, a gas supply line 420, and a gas storage unit 430. The gas supply nozzle 410 may be installed at the center of the upper surface of the chamber 100. A jetting port may be formed on the bottom surface of the gas supply nozzle 410. The injection port can supply the process gas into the chamber 100. The gas supply line 420 may connect the gas supply nozzle 410 and the gas storage unit 430. The gas supply line 420 may supply the process gas stored in the gas storage unit 430 to the gas supply nozzle 410. A valve 421 may be installed in the gas supply line 420. The valve 421 opens and closes the gas supply line 420 and can control the flow rate of the process gas supplied through the gas supply line 420.

The baffle unit 500 may be positioned between the inner wall of the chamber 100 and the substrate support assembly 200. The baffle 510 may be provided in an annular ring shape. A plurality of through holes 511 may be formed in the baffle 510. The process gas provided in the chamber 100 may be exhausted to the exhaust hole 102 through the through holes 511 of the baffle 510. [ The flow of the process gas can be controlled according to the shape of the baffle 510 and the shape of the through holes 511. [

The plasma generating unit may excite the process gas in the chamber 100 into a plasma state. The plasma generating unit may use a capacitively coupled plasma (CCP) type plasma source. When a plasma source of the CCP type is used, the upper electrode and the lower electrode may be included in the chamber 100. The upper electrode and the lower electrode may be arranged vertically in parallel with each other in the chamber 100. Either one of the electrodes can apply high-frequency power and the other electrode can be grounded. An electromagnetic field is formed in a space between both electrodes, and a process gas supplied to this space can be excited into a plasma state. The substrate processing process can be performed using this plasma. According to an example, the upper electrode may be provided to the showerhead 300 and the lower electrode may be provided to the body 230. High-frequency power may be applied to the lower electrode, and the upper electrode may be grounded. Alternatively, high-frequency power may be applied to both the upper electrode and the lower electrode. Thus, an electromagnetic field may be generated between the upper electrode and the lower electrode. The generated electromagnetic field can excite the process gas provided inside the chamber 100 into a plasma state.

Hereinafter, a process of processing a substrate using the above-described substrate processing apparatus will be described.

When the substrate W is placed on the substrate support assembly 200, a direct current may be applied from the first power source 223a to the first electrode 223. An electrostatic force is applied between the first electrode 223 and the substrate W by the DC current applied to the first electrode 223 and the substrate W can be attracted to the electrostatic chuck 210 by the electrostatic force.

When the substrate W is adsorbed to the electrostatic chuck 210, the process gas can be supplied into the chamber 100 through the gas supply nozzle 410. The process gas can be uniformly injected into the inner region of the chamber 100 through the injection hole 311 of the shower head 300. [ The high frequency power generated by the third power source 235a may be applied to the body 230 provided as a lower electrode. The spray plate 310 of the showerhead provided as the upper electrode can be grounded. An electromagnetic force may be generated between the upper electrode and the lower electrode. The electromagnetic force may excite the plasma of the process gas between the substrate support assembly 200 and the showerhead 300. The plasma may be provided to the substrate W to process the substrate W. [ The plasma may be subjected to an etching process.

The substrate processing apparatus 10 shown in FIG. 1 generates a plasma by generating an electric field in the chamber 100 using a plasma source of a capacitively coupled plasma (CCP) type (for example, an electrode installed in the chamber). However, the substrate processing apparatus 10 is not limited to this, and may generate plasma by inducing an electromagnetic field using a plasma source of ICP (Inductively Coupled Plasma) type (for example, a coil installed outside or inside the chamber) You may.

2 is an exemplary diagram schematically showing a plasma generating apparatus 600 according to an embodiment of the present invention.

The plasma generator 600 includes a first RF power source 611, a first plasma source 610, a second plasma source 630, and a second plasma source 630. The plasma generator 600 includes a first RF power source 611, A source 612, a second RF power source 621, a second plasma source 622, a sensing unit 624, and a control unit 630.

The first RF power source 611 supplies a first RF signal and the second RF power source 621 supplies a second RF signal. The first RF signal is supplied to a first plasma source 612 provided in the chamber 100 and the second RF signal is supplied to a second plasma source 622 provided in the chamber 100, The process gas supplied to the chamber 100 is excited into a plasma state.

The first and second plasma sources 612 and 622 shown in FIG. 2 correspond to the upper and lower electrodes, respectively, of the parallel plate electrodes disposed in the chamber 100, but the first and second plasma sources And is not limited to one parallel plate electrode that operates to generate plasma in the chamber 100.

For example, the first plasma source may include an antenna disposed on the top or side of the chamber 100 instead of the top electrode, wherein the first plasma source comprises an inductively coupled plasma source.

According to an embodiment, the first and second RF signals may be supplied to the same plasma source. In this case, the first and second plasma sources 612 and 622 are the same parts. For example, unlike FIG. 2, the upper electrode provided in the chamber 100 may be grounded, and the first and second RF signals may be supplied to the lower electrode to generate plasma in the chamber 100.

As described above, the type of the plasma source in the plasma generating apparatus 600 to which the embodiment of the present invention is applied is not limited to any one.

The parameters of the first RF signal and the second RF signal may be different from each other.

For example, the first and second RF signals may have different frequencies.

3 is an exemplary diagram illustrating waveforms and phase differences of first and second RF signals in accordance with an embodiment of the present invention.

As shown in FIG. 3, the frequency of the first RF signal may be higher than that of the second RF signal.

For example, the frequency f1 of the first RF signal is n times the frequency f2 of the second RF signal, where n is a real number greater than one (i.e., f1 = n.f2).

According to an embodiment, the frequencies of the first and second RF signals may be the same. In this case, n becomes 1.

The magnitude (e.g., amplitude) of the first RF signal and the magnitude of the second RF signal may differ according to the process performed by the substrate processing apparatus 100, but may be the same according to the embodiment.

The parameters such as the frequency and the size of the first and second RF signals may be set in a recipe previously prepared in accordance with the process performed in the substrate processing apparatus 10, And executes the process according to the recipe.

Further, the controller 630 adjusts the phase difference between the first RF signal and the second RF signal. According to an embodiment of the present invention, the plasma generator 600 includes a sensing unit 624 provided at an input terminal of a second plasma source to sense a parameter of the second RF signal, and the controller 630 The impedance of the plasma is measured using the parameters sensed by the sensing unit 624 and the phase difference between the first and second RF signals is adjusted based on the measured impedance.

According to one embodiment, the sensing unit 624 may include a sensor for sensing the voltage and current of the second RF signal. That is, the plasma generator 600 includes a sensor capable of sensing voltage and current at an input terminal of the second plasma source 622, and a voltage of a second RF signal applied to the second plasma source 622 And the current parameter to the control unit 630.

Then, the controller 630 can measure the impedance of the plasma using the voltage and current parameters of the second RF signal provided from the sensing unit 624. For example, the controller 630 can determine the value obtained by dividing the voltage of the second RF signal by the current using the Ohm's law as the impedance of the plasma.

Referring again to FIG. 2, the plasma generator 600 may further include first and second impedance matchers 613 and 623.

The first impedance matcher 613 is provided between the first RF power source 611 and the first plasma source 612 to adjust the output impedance of the first RF power source 611 and the input impedance of the first plasma source 612, Lt; / RTI > The second impedance matcher 623 is provided between the second RF power source 621 and the second plasma source 622 and is connected between the output impedance of the second RF power source 621 and the input impedance of the second plasma source 622, Lt; / RTI >

In this case, the sensing unit 624 may be provided between the second impedance matcher 623 and the second plasma source 622.

The embodiment of the present invention measures the impedance of the plasma formed in the chamber 100 by using the parameter of the second RF signal sensed by the sensing unit 624 and outputs the first and second RF signals To adjust the phase difference?

The plurality of RF signals used in the plasma process are applied to the plasma sources 612 and 622 with a phase difference? Even when the first and second RF signals having different frequencies are used, there is a phase difference of 0 to 360 degrees between the phase of the first RF signal and the phase of the second RF signal at a timing corresponding to one time point on the time axis.

Referring to the waveforms of the first and second RF signals shown in FIG. 2, the second RF signal is ahead of the first RF signal by a phase difference? At a timing corresponding to time t = 0.

In order to adjust the phase difference between the first and second RF signals, the control unit 630 first aligns the phases of the first RF signal and the second RF signal, The impedance of the plasma may be measured while changing the phase difference between the signal and the second RF signal to obtain a first phase difference set for the phase difference and a first impedance set for the impedance related to the phase difference.

Then, the controller 630 obtains a target phase difference representing an extremum and the extremum of the function representing the impedance for the phase difference based on the first phase difference set and the first impedance set, And at least one of the first and second RF power supplies so that the phase difference between the two RF signals is the target phase difference.

FIG. 4 is a graph showing a coordinate formed by a phase difference? Between first and second RF signals and a corresponding impedance Z on a two-dimensional coordinate plane according to an embodiment of the present invention.

As described above, the controller 630 may first phase-align the first RF signal and the second RF signal to adjust the phase difference between the first and second RF signals. In other words, the controller 630 may control at least one of the first and second RF power supplies so that the phase difference? Is zero.

Then, the controller 630 may measure the impedance Z of the plasma for each phase difference? While changing the phase difference? Between the first and second RF signals. As described above, the impedance Z may be measured using the parameters of the second RF signal sensed by the sensing unit 624.

For example, the controller 630 may gradually increase the phase difference? Between the first and second RF signals by a predetermined increment, measure the impedance Z, and calculate a first phase difference set composed of phase differences, It is possible to obtain a first impedance set composed of corresponding impedances.

Referring to FIG. 4, the controller 630 obtains a first phase difference set consisting of six phase differences and a first impedance set composed of a total of six impedances corresponding to the phase differences, The phase difference set and the first impedance set form a total of six coordinate points on the two-dimensional coordinate plane composed of the coordinate axes related to the phase difference? And the coordinate axes related to the impedance Z.

In Fig. 4, the increment of the phase difference [phi] is 30 [deg.], But the phase difference increment in the present invention is not limited thereto. Also, the acquisition of the first set of phase differences and the first set of impedances may be repeatedly performed until the phase difference between the first and second RF signals is greater than or equal to 180 [deg.] (I.e., ≪ 180, the impedance Z for the phase difference? Is measured to form one coordinate).

Then, the controller 630 can obtain the extremum of the function representing the impedance Z with respect to the phase difference? Based on the first set of phase difference and the first set of impedances and the target phase difference? _T indicating the extremum.

In Figure 4, from among the six coordinates shown in the two-dimensional coordinate plane in the φ-Z P ₄ that has an impedance Z ₄ corresponding to the maximum value, the impedance Z ₄ phase difference φ ₄ is the target phase difference φ _t corresponding to .

Then, the controller 630 is first the first and the 2 RF power source so that the RF signal and the 2 RF signal between the phase difference φ determined target phase difference φ _t (611, 612) at least one controlling of can do.

In other words, according to the embodiment of the present invention described above, the phase difference? Between the first RF signal supplied from the first RF power source 611 and the second RF signal supplied from the second RF power source 621, Dimensional coordinates from a first set of impedances consisting of a first phase difference set having different values of phase differences and impedances related thereto, and determining a function defined by the two-dimensional coordinates (i.e., a phase difference? And a function Z = f (?) Having the impedance Z as a conjugate) can be determined as the target phase difference? _T.

According to another embodiment of the present invention, the controller 630 may perform more reliable phase difference control through statistical analysis.

According to this embodiment, the control unit 630 first adjusts the impedance Z of the plasma by changing the phase difference between the first RF signal and the second RF signal and the phase difference between the first RF signal and the second RF signal, To obtain a first set of phase differences for the phase difference and a first set of impedances associated with that phase difference. This is the same as the embodiment of the present invention described above with reference to FIG.

Then, the controller 630 may calculate the average and standard deviation of the impedance from the first impedance set. Then, the controller 630 determines one of the impedances distributed within the standard deviation from the average among the impedances belonging to the first impedance set and the phase difference corresponding to the impedance as the starting impedance and the starting phase difference, respectively .

5 is an exemplary distribution diagram derived on the basis of mean m and standard deviation sigma of impedance in accordance with another embodiment of the present invention.

As described above, when the first phase difference set and the first impedance set are obtained, the controller 630 calculates an average m and a standard deviation? Of impedances belonging to the first impedance set.

Then, based on the calculated average m and standard deviation?, Any one of the impedances distributed within the range of the standard deviation? From the average m among the impedances belonging to the first impedance set is determined as the starting impedance, The corresponding phase difference can be determined as the starting phase difference _ss .

Here, according to the embodiment of the present invention, the distribution of the first impedance set can be previously defined as following the normal distribution, and the range of the standard deviation sigma from the average m in this case is the area shown by the hatched portion of FIG. 5 .

The controller 630 determines one of the impedances distributed in the region corresponding to the hatched portion, that is, dispersed within the range of the standard deviation? From the average m of the impedances constituting the first impedance set, to the starting impedance And the phase difference? Indicating the starting impedance thereof can be determined as the starting phase difference.

According to one embodiment, the starting impedance may be determined as a minimum value or a maximum value among the impedances of the first impedance set distributed within the range of the mean deviation m from the mean value m, and the starting phase difference _ss is the minimum value or the maximum value The phase difference < RTI ID = 0.0 >

The controller 630 may then control at least one of the first and second RF power supplies 611 and 612 such that the phase difference between the first and second RF signals is the starting phase difference _s have. The control unit 630 measures the impedance of the plasma while changing the phase difference? From the starting phase difference? _S to determine a second phase difference set for the phase difference and a second impedance set for the impedance related to the phase difference Can be obtained.

Then, the control unit 630 obtains a target phase difference? _T indicating an extremum of the function and an extremum of the impedance Z for the phase difference? Based on the second phase difference set and the second impedance set, And at least one of the first and second RF power supplies 611 and 612 so that the phase difference between the first and second RF signals is the target phase difference.

FIG. 6 is a graph showing the phase difference between the first and second RF signals and the impedance Z corresponding thereto in a two-dimensional coordinate plane according to another embodiment of the present invention. Referring to FIG.

Unlike the graph shown in Figure 4, the second phase also the graph on the φ-Z coordinate plane shown in Figure 6, while gradually increasing the phase difference φ to the previously-determined start from the phase difference φ _s is obtained by measuring the impedance Z And a second set of impedances.

Further, according to this embodiment, the acquisition of the second set of phase differences and the second set of impedances may be achieved by increasing the phase difference [phi] between the first and second RF signals so that the measured impedance is less than the standard deviation [ can be repeated until it exceeds the range of? (i.e., the hatched region in FIG. 5).

In addition, in this embodiment, the increment of the phase difference? May be less than the increment of the phase difference? That was applied when acquiring the first phase difference set and the first impedance set. For example, the phase difference increment [Delta] [phi] ₂ used for acquiring the second phase difference set and the second impedance set is one fifth of the phase difference increment [Delta] [phi] ₁ used for obtaining the first phase difference set and the first impedance set But are not limited thereto.

Thus, this embodiment further acquires a second set of phase differences and a second set of impedances based on the impedances distributed within a certain range from the mean m of the impedance calculated from the first set of impedances and the corresponding phase differences, The two-dimensional coordinates are determined, and the phase difference representing the maximum value or minimum value of the function Z = f (?) Defined by the two-dimensional coordinates can be determined as the target phase difference? _T.

Then, the control unit 630 includes first and second RF signals between the phase difference φ is the target phase difference of the first and second RF power source (611, 621) such that φ _t to control at least one of: have.

In the embodiments of the present invention described above, the controller 630 adjusts the phase difference between the first and second RF signals by adjusting the phase of the first RF signal and the phase of the second RF signal, It can be adjusted to φ _t . That is, among the first and second RF signals, the RF signal, which is relatively high in frequency, affects the phase of the RF signal, which is involved in the generation of the plasma, and the phase of the RF signal, To adjust the phase difference between the RF signals.

7 is an exemplary flow diagram of a method 700 for adjusting a phase difference in accordance with an embodiment of the present invention.

The phase difference control method 700 is performed by the plasma generator 600 according to the embodiment of the present invention described above and more specifically the controller 630 controls the phase difference control method 700 And can be achieved by loading and executing a program. The controller 630 is a processor that processes data according to a predetermined algorithm, and includes, for example, a CPU, but is not limited thereto. The program is stored in a predetermined storage device (not shown), and the control unit 630 executes a program from the storage device to execute a phase difference adjustment method 700 described later.

Referring to FIG. 7, the method 700 includes a first RF source 611 and a second RF source 621 for respectively supplying a first RF signal and a second RF signal to a first plasma source 612, (S710) to a second plasma source (622), sensing (S720) a parameter of a second RF signal supplied to a second plasma source (622), and determining And adjusting a phase difference? Between the first RF signal and the second RF signal based on the impedance Z of the plasma (S730).

The frequency of the first RF signal may be higher than or equal to the frequency of the second RF signal. For example, the frequency of the first RF signal may be n times the frequency of the second RF signal, where n may be a real number greater than or equal to one.

According to one embodiment, the first plasma source 612 includes an upper electrode of the parallel plate electrodes disposed in the chamber 100, and the second plasma source 622 includes a lower electrode of the parallel plate electrodes However, the plasma source to which the present invention is applicable is not limited to the CCP type.

The step S720 of sensing the parameters of the second RF signal may include sensing the voltage and current of the second RF signal. The detection of the parameter may be performed by a sensor provided at the input end of the second plasma source 622.

8 is an exemplary flow chart illustrating the process of adjusting the phase difference? Between the first and second RF signals (S730) according to an embodiment of the present invention.

Referring to FIG. 8, the step of adjusting the phase difference (S730) may include the step of matching the phases of the first RF signal and the second RF signal (S731), the phase difference between the first RF signal and the second RF signal (S732) of measuring a impedance Z while changing the phase difference? and obtaining a first set of phase differences for the phase difference? and a first set of impedances for an impedance Z related to the phase difference S732, (Step S733) of obtaining an extremum of a function indicating an impedance Z with respect to a phase difference? Based on the set and a target phase difference? _T indicating the extremum, and calculating a phase difference? Between the first RF signal and the second RF signal And controlling (S734) at least one of the first RF power source 611 and the second RF power source 621 so as to be the target phase difference phi _t .

In this embodiment, the step (S732) of acquiring the first set of phase differences and the first set of impedances is repeated until the phase difference? Between the first RF signal and the second RF signal is greater than or equal to 180 degrees. Lt; / RTI >

FIG. 9 is an exemplary flow chart illustrating the process of adjusting the phase difference between first and second RF signals, S, in accordance with another embodiment of the present invention (S730).

Referring to FIG. 9, in operation S730, the phase difference is adjusted by matching the phase of the first RF signal with the phase of the second RF signal S731, (step S732) of measuring the impedance Z while changing the phase difference? to obtain a first phase difference set for the phase difference? and a first impedance set for the impedance Z related to the phase difference (S732) Which is the same as the embodiment.

Thereafter, the step of adjusting the phase difference (S730) includes calculating an average m and a standard deviation? Of the impedance Z from the first impedance set (S735), calculating the average m from step (S736), the 1 RF signals and the 2 RF signal to determine a phase difference, respectively a starting impedance and from the phase difference φ _s which corresponds to any of impedance and the impedance of which is dispersed in the range of the standard deviation σ (S737) controlling at least one of the first RF power source 611 and the second RF power source 621 so that the phase difference between the first RF signal and the second RF signal becomes the starting phase difference? _S , Measuring impedance Z while changing the difference? To obtain a second phase difference set for the phase difference? And a second impedance set for the impedance Z related to the phase difference (S738), a second phase difference set and a second phase difference set Obtaining a target phase difference φ _t represents the peak and the peak of a function that represents the impedance of the impedance phase difference φ, based on the scan set (S739), and a first RF signal with claim 2 RF signal between the phase difference φ And controlling at least one of the first RF power source 611 and the second RF power source 621 to be the target phase difference? _T (S734).

According to the embodiments of the present invention described above, by adjusting the phase difference between a plurality of RF signals used for a plasma process appropriately for the equipment, the characteristics and the process rate of the plasma in the chamber are improved to improve the productivity of the substrate processing process .

While the present invention has been described with reference to the exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. Those skilled in the art will appreciate that various modifications may be made to the embodiments described above. The scope of the present invention is defined only by the interpretation of the appended claims.

10: substrate processing apparatus
100: chamber
200: substrate support assembly
300: Shower head
400: gas supply unit
500: Baffle unit
600: Plasma generator
611: First RF power source
612: a first plasma source
613: First Impedance Matcher
621: Second RF power source
622: a second plasma source
623: Second Impedance Matcher
624:
630:
W: substrate
φ: phase difference
Z: Impedance

Claims (20)

A first RF power supply for supplying a first RF signal;
A first plasma source for generating plasma by receiving the first RF signal;
A second RF power supply for supplying a second RF signal;
A second plasma source for generating a plasma by receiving the second RF signal;
A sensing unit provided at an input terminal of the second plasma source to sense a parameter of the second RF signal; And
A controller for measuring an impedance of the plasma using the sensed parameter and adjusting a phase difference between the first RF signal and the second RF signal such that the measured impedance of the plasma is maximized;
And a plasma generator. The method according to claim 1,
Wherein the frequency of the first RF signal is higher than the frequency of the second RF signal. 3. The method of claim 2,
Wherein the frequency of the first RF signal is n times the frequency of the second RF signal, where n is a real number equal to or greater than one. The method according to claim 1,
Wherein the first plasma source comprises an upper electrode of parallel plate electrodes disposed in a plasma chamber,
And the second plasma source comprises a lower electrode of the parallel plate electrodes. The method according to claim 1,
The sensing unit includes:
And a sensor for sensing the voltage and current of the second RF signal. The method according to claim 1,
A first impedance matcher provided between the first RF power source and the first plasma source to match an output impedance of the first RF power source with an input impedance of the first plasma source; And
A second impedance matcher provided between the second RF power source and the second plasma source for matching the output impedance of the second RF power source with the input impedance of the second plasma source;
Further comprising a plasma generator. The method according to claim 1,
The control unit includes:
The first RF signal and the second RF signal are in phase with each other,
Measuring the impedance while changing the phase difference between the first RF signal and the second RF signal to obtain a first phase difference set for the phase difference and a first impedance set for the impedance related to the phase difference,
Obtaining a target phase difference representing an extremum and the extremum of the function indicative of the impedance for the phase difference based on the first set of phase differences and the first set of impedances,
And controls at least one of the first RF power source and the second RF power source such that a phase difference between the first RF signal and the second RF signal is the target phase difference. The method according to claim 1,
The control unit includes:
The first RF signal and the second RF signal are in phase with each other,
Measuring the impedance while changing the phase difference between the first RF signal and the second RF signal to obtain a first phase difference set for the phase difference and a first impedance set for the impedance related to the phase difference,
Calculating an average and standard deviation of the impedance from the first set of impedances,
Determining one of the impedances distributed within the standard deviation from the average among the impedances belonging to the first impedance set and the phase difference corresponding to the impedance as the starting impedance and the starting phase difference,
Controlling at least one of the first RF power source and the second RF power source such that a phase difference between the first RF signal and the second RF signal is the starting phase difference,
Measuring the impedance while changing a phase difference between the first RF signal and the second RF signal to obtain a second phase difference set for the phase difference and a second impedance set for the impedance related to the phase difference,
Obtaining a target phase difference representing an extremum and the extremum of the function indicative of the impedance for the phase difference based on the second set of phase differences and the second set of impedances,
And controls at least one of the first RF power source and the second RF power source such that a phase difference between the first RF signal and the second RF signal is the target phase difference. 9. The method according to claim 7 or 8,
Wherein the acquisition of the first set of phase differences and the first set of impedances is repeated until the phase difference between the first RF signal and the second RF signal is greater than or equal to 180 °. 9. The method of claim 8,
The acquisition of the second phase difference set and the second impedance set is repeated by changing the phase difference between the first RF signal and the second RF signal until the measured impedance deviates from the average out of the standard deviation And a plasma generator. Supplying a first RF signal and a second RF signal from a first RF power source and a second RF power source to a first plasma source and a second plasma source, respectively;
Sensing a parameter of the second RF signal supplied to the second plasma source; And
Adjusting a phase difference between the first RF signal and the second RF signal such that an impedance of the plasma measured using the sensed parameter is maximized;
/ RTI > 12. The method of claim 11,
Wherein the frequency of the first RF signal is higher than or equal to the frequency of the second RF signal. 13. The method of claim 12,
Wherein the frequency of the first RF signal is n times the frequency of the second RF signal, where n is a real number greater than or equal to 1. 12. The method of claim 11,
Wherein the first plasma source comprises an upper electrode of parallel plate electrodes disposed in a plasma chamber,
And the second plasma source includes a lower electrode of the parallel flat plate electrodes. 12. The method of claim 11,
Wherein sensing the parameters of the second RF signal comprises:
And sensing the voltage and current of the second RF signal. 12. The method of claim 11,
Wherein adjusting the phase difference comprises:
Matching phases of the first RF signal and the second RF signal;
Measuring the impedance while changing the phase difference between the first RF signal and the second RF signal to obtain a first phase difference set for the phase difference and a first impedance set for the impedance related to the phase difference, ;
Obtaining a target phase difference representing an extremum of the function and the extremum representing the impedance for the phase difference based on the first set of phase differences and the first set of impedances; And
Controlling at least one of the first RF power source and the second RF power source such that a phase difference between the first RF signal and the second RF signal is the target phase difference;
/ RTI > 12. The method of claim 11,
Wherein adjusting the phase difference comprises:
Matching phases of the first RF signal and the second RF signal;
Measuring the impedance while changing the phase difference between the first RF signal and the second RF signal to obtain a first phase difference set for the phase difference and a first impedance set for the impedance related to the phase difference, ;
Calculating an average and standard deviation of the impedance from the first set of impedances;
Determining one of the impedances distributed within the standard deviation from the average among the impedances belonging to the first impedance set and the phase difference corresponding to the impedance as the starting impedance and the starting phase difference, respectively;
Controlling at least one of the first RF power source and the second RF power source such that a phase difference between the first RF signal and the second RF signal is the starting phase difference;
Measuring the impedance while changing the phase difference between the first RF signal and the second RF signal to obtain a second phase difference set for the phase difference and a second impedance set for the impedance related to the phase difference, ;
Obtaining a target phase difference representing an extremum and the extremum of the function indicative of the impedance for the phase difference based on the second set of phase differences and the second set of impedances; And
Controlling at least one of the first RF power source and the second RF power source such that a phase difference between the first RF signal and the second RF signal is the target phase difference;
/ RTI > 18. The method according to claim 16 or 17,
Wherein obtaining the first set of phase differences and the first set of impedances comprises:
Wherein the phase difference is repeatedly performed until a phase difference between the first RF signal and the second RF signal is greater than or equal to 180 °. 18. The method of claim 17,
Wherein obtaining the second set of phase differences and the second set of impedances comprises:
And varying the phase difference between the first RF signal and the second RF signal to be repeatedly performed until the measured impedance deviates from the average to the range of the standard deviation. A chamber for providing a space in which the substrate is processed;
A substrate support assembly for supporting the substrate within the chamber;
A gas supply unit for supplying gas into the chamber; And
And a plasma generating unit that excites gas in the chamber into a plasma state, the plasma generating unit comprising:
A first RF power supply for supplying a first RF signal;
A first plasma source for generating plasma by receiving the first RF signal;
A second RF power supply for supplying a second RF signal;
A second plasma source for generating a plasma by receiving the second RF signal;
A sensing unit provided at an input terminal of the second plasma source to sense a parameter of the second RF signal; And
A controller for measuring an impedance of the plasma using the sensed parameter and adjusting a phase difference between the first RF signal and the second RF signal such that the measured impedance of the plasma is maximized;
And the substrate processing apparatus.

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