WO2015014068A1 - Radio frequency power supply system, and method for performing impedance matching by using radio frequency power supply system - Google Patents

Abstract

The present invention provides a radio frequency power supply system. The radio frequency power supply system comprises a radio frequency power supply, and an automatic impedance matcher electrically between the radio frequency power supply and a plasma chamber. The frequency of the radio frequency power supply can be adjusted between the minimum preset frequency and the maximum preset frequency, and by means of adjustment of the frequency of the radio frequency power supply and adjustment of input impedance of a matching network by using the automatic impedance matcher, the input impedance of the matching network is equal to constant output impedance of the radio frequency power supply. The present invention further provides a method for performing impedance matching by using a radio frequency power supply system. By means of the radio frequency power supply system of the present invention, impedance matching can be achieved within a short time.

Description

 RF power system and method for impedance matching using RF power system

 The present invention relates to the field of impedance matching technology, and in particular to a radio frequency power system and a method for impedance matching using the radio frequency power system. Background technique

 Please refer to FIG. 1 , which is a schematic structural diagram of a conventional RF automatic impedance matching device. As shown in Figure 1, in a typical RF plasma generator, a constant output impedance RF power supply

10 produces a fixed frequency radio frequency wave that provides RF power to the plasma chamber 30 to excite a plasma for etching or for other processes. Among them, the constant output impedance of the RF generator is usually 50Ω, and the fixed frequency generated is usually 13.56MHz. In general, the nonlinear load impedance of the plasma chamber 30 is not equal to the constant output impedance of the RF power source 10, so there is a relatively serious impedance mismatch between the RF power source 10 and the plasma chamber 30, thereby causing There is a large reflected power on the radio frequency transmission line between the RF power source 10 and the plasma chamber 30, so that the power generated by the RF power source 10 cannot be completely delivered to the plasma chamber 30.

To solve this problem, an automatic impedance matcher 20 is typically disposed between the RF power source 10 and the plasma chamber 30 in the prior art, as shown in FIG. The automatic impedance matcher 20 includes an impedance sensor 22, a controller 21, and an actuator 23, wherein the actuator 23 further includes a variable impedance element in the matching network and a driving device that changes the value of the variable impedance element. The matching network referred to herein refers to a network composed of a variable impedance element and a nonlinear load impedance of the plasma chamber 30. The impedance sensor 22 detects parameters such as voltage, current, forward power, and reverse power on the RF transmission line between the automatic impedance matcher 20 and the RF power source 10 to provide the controller 21 with the amount of input required to match the control algorithm. The input is typically a further calculated parameter based on parameters such as voltage, current, forward power, and reverse power. Wherein, the reverse power is the reflected power introduced above, and the impedance sensor 22 is also used to detect the input impedance of the matching network. Output to the controller 21. The controller 21 uses a matching control algorithm according to the input amount provided by the impedance sensor 22 and the input impedance of the matching network, and deletes the adjustment amount of the variable impedance element, and outputs it to the driving device in the actuator 23, the driving device is based on The amount of adjustment of the controller 21 changes the impedance of the variable impedance element such that the input impedance of the matching network is equal to the constant output impedance of the RF power source 10, i.e., impedance matching is achieved. Thus, the reflected power on the RF transmission line is zero, and the power generated by the RF generator is all delivered to the plasma chamber 30.

 Due to the small number of adjustable components, the matching range of the entire matching system is narrow. If a variable-range component is selected, the response speed is slower and the cost is higher. Therefore, how to adjust the adjustment range of the impedance matching system and improve the response speed of the impedance matching system have become technical problems to be solved in the art. Summary of the invention

 It is an object of the present invention to provide a radio frequency power system and a method for impedance matching using the radio frequency power system, which can quickly perform impedance matching.

 In order to achieve the above object, as an aspect of the present invention, a radio frequency power supply system including an RF power source and an automatic impedance matching device electrically connected between the RF power source and a plasma chamber is provided, wherein The frequency of the RF power source can be adjusted between a minimum predetermined frequency and a maximum predetermined frequency, and the input impedance of the matching network can be made to the RF by adjusting the frequency of the RF power source and adjusting the input impedance of the matching network by the automatic impedance matcher The constant output impedance of the power supply is equal.

Preferably, the automatic impedance matching device includes an impedance sensor, a controller, and an actuator, wherein the impedance sensor is configured to detect an initial impedance of the actuator and an initial frequency of the RF power source, and initialize the actuator An impedance and an initial frequency of the RF power source are sent to the controller, the controller being capable of calculating the initial impedance according to the actuator, an initial frequency of the RF power source, and an equivalent impedance of the plasma chamber Matching the initial input impedance of the network and adjusting the frequency of the RF power source and controlling the impedance of the actuator based on the initial input impedance. Preferably, the actuator comprises an impedance tunable element and a transformer having an adjustable turns ratio, and the real part of the impedance value of the input impedance of the matching network can be adjusted by adjusting the turns ratio of the transformer, by adjusting the impedance The impedance of the tunable element is capable of adjusting the imaginary part of the impedance value of the input impedance of the matching network.

 Preferably, the impedance tunable element comprises a first capacitor and an inductor, the first capacitor and the inductor are connected in series with the plasma chamber, the first capacitor is a tunable capacitor, and/or the inductor is a tunable inductor .

 Preferably, the first capacitor and the inductor are both connected in series at an input end of the transformer. Preferably, the impedance tunable elements are all disposed at an output end of the transformer, and the impedance tunable component comprises a second capacitor and a third capacitor, the second capacitor is a tunable capacitor, and the second capacitor In parallel with the plasma chamber, the third capacitor is in series with the plasma chamber.

 As another aspect of the present invention, there is provided a method for impedance matching using a radio frequency power system, the radio frequency power system comprising a radio frequency power source, an automatic impedance matching device electrically connected between the radio frequency power source and a plasma chamber, The frequency of the radio frequency power source can be adjusted between a minimum predetermined frequency and a maximum predetermined frequency, and the automatic impedance matching method includes:

 Step 100: Acquire an equivalent impedance of the predetermined plasma chamber by using an automatic impedance matching device, and calculate an initial input impedance of the matching network;

 Step 200: Adjust a frequency of the RF power source, and adjust an input impedance of the matching network by using the automatic impedance matching device, so that an input impedance of the matching network is equal to a constant output impedance of the RF power source.

 Preferably, the automatic impedance matcher includes an impedance sensor, a controller and an actuator; the step 100 includes detecting, by the impedance sensor, an initial input impedance of the matching network and an initial frequency of the RF power source, and An initial input impedance of the matching network and an initial frequency of the radio frequency power source are sent to the controller, and the controller is used to calculate an initial input impedance of the matching network;

The step 200 includes utilizing the controller according to an initial input impedance of the matching network The frequency of the RF power source is adjusted and the impedance of the actuator is controlled.

 Preferably, the actuator comprises an impedance tunable element and a transformer having an adjustable turns ratio; the step 200 includes:

 Adjusting a turns ratio of the transformer such that a real portion of the impedance value of the input impedance of the matching network is equal to a constant output impedance of the RF power source;

 The impedance of the impedance tunable element and the frequency of the RF power source are adjusted such that the imaginary part of the impedance value of the input impedance of the matching network is zero.

 Preferably, the step of "adjusting the impedance of the impedance tunable element and the frequency of the radio frequency power source such that the imaginary part of the impedance value of the input impedance of the matching network is zero" includes:

 Step 221: Determine a matching frequency of the RF power source when an input impedance of the matching network is equal to a constant output impedance of the RF power source according to a relationship between the matching initial impedance and an initial RF frequency of the RF power source. ;

 Step 222: Adjust the impedance tunable component such that an input impedance of the matching network is equal to a constant output impedance of the RF power source.

 In the present invention, the automatic impedance matcher can adjust the input impedance of the matching network. Similar to the prior art, the automatic impedance matcher can also include an impedance tunable element that adjusts the input impedance of the matching network by adjusting the impedance of the impedance tunable element. By combining the adjustment of the RF power frequency with the adjustment of the matching network by the automatic impedance matcher, the matching range of the entire RF power system can be increased. Moreover, in the automatic impedance matching using the RF power supply system provided by the present invention, it is not necessary to increase the adjustment range of the impedance tunable component in the automatic impedance matching device, so that impedance matching can be achieved in a shorter time. DRAWINGS

The drawings are intended to provide a further understanding of the invention and are intended to be a In the drawing: 1 is a schematic structural diagram of a conventional radio frequency automatic impedance matching device;

 2 is a schematic structural view of a radio frequency power supply system according to the present invention;

 3 is a schematic diagram of a first embodiment of a radio frequency power system according to the present invention; FIG. 4 is a schematic diagram of a second embodiment of the radio frequency power system according to the present invention; FIG. 6 is a schematic diagram of a fourth embodiment of the radio frequency power system according to the present invention; FIG. 7 is a schematic diagram of a fifth embodiment of the radio frequency power system according to the present invention; 8 is a flow chart of a method 200 of the method described in FIG. 8 for a method of impedance matching using the RF power system of the present invention. Description of the reference signs:

 10: RF power supply 20: Automatic impedance matcher

 21 : Controller 22: Impedance sensor

 23: Actuator 30: Plasma chamber

 23a: Transformer 23b: Impedance adjustable component

 231b: Inductance 232b: First capacitor

 233b: second capacitor 234b: third capacitor

 The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It is to be understood that the specific embodiments described herein are intended to be illustrative and not restrictive.

As shown in FIG. 2, as an aspect of the present invention, an RF automatic matching system is provided. The RF automatic matching system includes a RF power source 10, a plasma chamber 30, and an electrical connection between the RF power source 10 and the plasma chamber 30. Automatic impedance matching device 20, wherein the frequency of the RF power supply 10 The rate can be adjusted between the minimum predetermined frequency _fmin and the maximum predetermined frequency _fmax , by adjusting the frequency of the RF power source 10, and adjusting the input impedance of the matching network by the automatic impedance matcher 20, enabling the input impedance of the matching network and the RF power source The constant output impedance of 10 is equal (ie, impedance matching).

 In the present invention, the automatic impedance matcher 20 can adjust the input impedance of the matching network. Similar to the prior art, the automatic impedance matcher 20 can also include an impedance tunable component that adjusts the input impedance of the matching network by adjusting the impedance of the impedance tunable component. By combining the frequency of the regulated RF power source 10 with the adjustment of the automatic impedance matcher 20 to the matching network, the matching range of the entire RF power system can be increased. Moreover, when the automatic impedance matching is performed by using the RF power supply system provided by the present invention, the adjustment range of the impedance tunable component in the automatic impedance matching device 20 can be eliminated, so that impedance matching can be achieved in a shorter time.

 Further, in the present invention, the frequency of the radio frequency power source 10 can be adjusted by digital adjustment. That is, the frequency of the RF power source 10 can be adjusted by setting the RF power source 10 by the controller.

 Typically, the impedance of the impedance tunable element is adjusted by mechanical adjustment. That is, typically the impedance tunable components include a tunable capacitor and a tunable inductor. The adjustable capacitor includes a capacitance adjusting device, and the adjustable inductor includes an inductance adjusting device. In this case, the automatic impedance matching device 20 further includes a capacitance adjusting motor connected to the adjustable capacitance capacity adjusting device and the adjustable inductor. The inductance adjustment device connected to the inductance adjustment device. The capacitance of the adjustable capacitor can be adjusted by adjusting the rotation of the motor, and the inductance of the adjustable inductor can be adjusted by adjusting the rotation of the motor.

 While the speed of digital adjustment is faster than the speed of mechanical adjustment, in the present invention, the frequency required for impedance matching can be further shortened by using the frequency-adjustable RF power source 10 and the automatic impedance matcher 20.

Since the adjustment range of the RF power supply 10 is large, when the RF power supply 10 provided by the present invention performs automatic impedance matching, the frequency of the RF power supply 10 can be adjusted to adjust the input impedance of the matching network to the vicinity of the matching impedance. Then, by fine-tuning the automatic impedance matching device 20, the input impedance of the matching network is equal to the constant output impedance of the RF power source 10, thereby further Reduce the time required for impedance matching.

 It will be understood by those skilled in the art that the frequency of the radio frequency power source 10 can be individually controlled. For example, a control panel that individually controls the frequency of the RF power source can be provided in the RF power system.

 Alternatively, the automatic impedance matching device 20 can be used to control the frequency of the RF power source 10, thereby facilitating automatic impedance matching. Further, in the present invention, the specific structure of the automatic impedance matching unit 20 is not particularly limited as long as the impedance of the matching network can be adjusted. Specifically, as shown in FIG. 2, the automatic impedance matcher 20 may include an impedance sensor 22, a controller 21, and an actuator 23 for detecting an initial impedance of the actuator and an initial frequency of the RF power source 10, and the actuator The initial impedance and the initial frequency of the RF power source 10 are sent to the controller 21. The controller 21 can calculate an initial input impedance of the matching network based on the equivalent impedance of the plasma chamber 30, the initial impedance of the actuator 23, and the initial frequency of the RF power source 10. The controller 21 can then adjust the frequency of the RF power source 10 and the impedance of the control actuator 23 based on the calculated initial input impedance of the matching network to achieve impedance matching.

Typically, the input impedance Z of the matching network is of the form Z = Z _a + Z _b , where Z _a is the real part of the input impedance Z and Z _b is the imaginary part of the input impedance Z. After impedance matching is achieved, the real part Z _a that needs to satisfy the input impedance Z is the constant output impedance of the RF power source 10, and the imaginary part z _{b of the} input impedance Z is zero.

Therefore, when the automatic impedance matching is implemented by using the RF power supply system provided by the present invention, the real part Z _a of the input impedance of the matching network can be first adjusted to the constant output impedance of the RF power supply 10, and then the input impedance of the matching network is virtualized. Z _b is zero adjustment unit.

As a preferred embodiment of the present invention, the actuator 23 may include a transformer 23a and an impedance tunable element 23b that are adjustable in turns ratio. The real part ∑ ₃ of the impedance value of the input impedance of the matching network can be adjusted to the constant output impedance of the RF power source 10 by adjusting the turns ratio of the transformer 23a.

 The imaginary part of the impedance value of the input impedance of the matching network can be adjusted to zero by adjusting the impedance of the impedance tunable element 23b.

In the present invention, the specific structure of the impedance tunable element 23b is not particularly limited as long as it is To adjust the imaginary part of the input impedance of the matching network to zero, for example, as shown in FIGS. 3 to 6, the impedance tunable element 23b includes a first capacitor 232b and an inductor 231b, the first capacitor 232b and the inductor 231b. In series with the plasma chamber 30, the first capacitor 232b is a tunable capacitor, and/or the inductor 231b is a tunable inductor.

 The working principle of the transformer 23a with adjustable turns ratio will be described below through a specific embodiment. As shown in FIG. 3, in the first embodiment of the RF power supply system provided by the present invention, the first capacitor 232b is a tunable capacitor, and the inductor 231b is a fixed inductor (ie, the inductor value is not adjustable), and the impedance tunable component 23b includes a first capacitor 232b and an inductor 231b, the first capacitor 232b and the inductor 231b being in series with the plasma chamber 30, the first capacitor 232b being a tunable capacitor. The equivalent impedance of the plasma chamber 30 is set to R + jX at this time.

 Therefore, the input impedance of the right part of the transformer in the figure is:

其中， C_232b,。为第一电容 232b的初始电容值（通常为第一电容 232b的 最大电容值的一半）， L_231b为电感 231b的电感值， ωο为射频电源 10的初始 角频率 （本领域技术人员应当理解的是， 射频电源 10的频率 f与角频率 ω 满足： ω=2π , no为变压器 23a的匝数比。 Z ₁ = R + jX + jo ₀ L _231b - j ^ The input impedance of the entire matching network is:

Among them, C _232b ,. The initial capacitance value of the first capacitor 232b (usually half of the maximum capacitance value of the first capacitor 232b), L _231b is the inductance value of the inductor 231b, and ωο is the initial angular frequency of the RF power source 10 (which should be understood by those skilled in the art) Yes, the frequency f of the RF power source 10 and the angular frequency ω satisfy: ω = 2π , no is the turns ratio of the transformer 23a.

₂ 1

2 n (X + <3⁄4 ₂₃₂₆ ) The real part of the input impedance of the matching network is "., the imaginary part is ^ ²³¹⁶ , .

 In -1, X is related to the type of plasma chamber 30 and may be inductive (COQLQ) or capacitive ( ).

It can be seen that the real part of the input impedance of the matching network is only related to the turns ratio of the transformer 23a, and the imaginary part is related to the angular frequency ω of the RF power source 10 and the capacitance value of the first capacitor 232b. Therefore, in the process of automatic matching, the real part and the imaginary part of the impedance can be adjusted at the same time, so that the real part is shot The constant output impedance of the frequency power supply 10 is R _{1 ()} (usually 50 Ω) and the imaginary part is zero. For example, when the equivalent impedance of the plasma chamber 30 is . When the impedance sensor detects the impedance Z. for:

+ L_231b ) ] 在阻抗匹配后， 变压器的匝数比为 实部" "^为射频电源 10的恒定 Z ₀ =n ² (R + jco ₀ L ₀ + jo ₀ L _231b - j ~ ) = n R +

+ L _231b ) ] After the impedance matching, the turns ratio of the transformer is the real part ""^ is the constant of the RF power supply 10

10

The output impedance R ₁₀ , therefore, the frequency of the RF power source 10 is co _m , the capacitance value of the first capacitor 232b w _m (L ₀ + L _i ) ^ = 0 is c _232b , _m , and the imaginary part satisfies the following formula: Therefore, the angular frequency of the RF power source 10 is co _m and the capacitance value C _{232bm of the} first capacitor 232b satisfies the formula:

( ) + 231 /?) C ₂₃₂ When using the RF power supply automatically matching impedance provided by the present invention, the turns ratio of the transformer 23a can be first "adjusted to" and then the angular frequency of the RF power supply 10 and the first capacitor 232b are respectively adjusted. The capacitance value such that the angular frequency of the RF power source 10 and the capacitance value of the first capacitor 232b satisfy

(^+^ ^ ²³²⁶ , "". It should be understood that 0) „ ₁ and ( ₂₃₂₁₅ , „ ₁ have no specific values.

 1

, 则将射频电源 10 的频率直接调至 / minSpecifically, first, the controller 21 calculates ^(Ζί+Ζ ^Χ^, . . . if the controller 21 calculates

, then adjust the frequency of the RF power supply 10 directly to / min

" _mi n = ² ^n ), then fine-tuning the capacitance value of the first capacitor 232b, so that

( o+Z^ C^ . At this time, the minimum angular frequency ( ₀₁ ^ _{1 is ω)}

1

Similarly, if ( ⁺ AK^ ²⁶ ,., the frequency of the RF power supply 10 is directly adjusted to ( ^ω ^ = 2 _min ), then the first capacitor 232b is fine-tuned such that ( ^L o + L _2nb ) _232b , _m . At this time, the maximum angular frequency Q) _{max is} Q) _m .

 1

If ^ + ^^ ^,. Between the minimum angular frequency _ωπώι and the maximum angular frequency _ωπ3⁄4χ , then

 1

Use the controller 21 to adjust the frequency of the RF power supply 10 to (+^ K^M, and then fine-tune the first power.

 twenty one

a? _mjn =

Capacitor 232b to make ⁺ 2316 ^. It should be understood that in the above three cases, when the impedance is matched, the frequency of the RF power source and the capacitance value of the first capacitor 232b are all unequal.

 In the second embodiment of the present invention, as shown in FIG. 4, the first capacitor 232b is an adjustable capacitor, and the inductor 231b is a variable inductor (ie, the inductor value is adjustable). When adjusting the imaginary part of the input impedance of the matching network, the first capacitor 232b and the inductor 231b can be adjusted at the same time, which is similar to the first embodiment, and will not be described again here. The matching time required for automatic impedance matching using the radio frequency system of the second embodiment of the present invention is shorter. Further, in the present invention, the positions at which the first capacitor 232b and the inductor 231b are disposed are not particularly limited. For example, in the third embodiment of the invention illustrated in Figure 5, the first capacitor 232b is coupled in series with the output of the transformer 23a and the inductor 231b is coupled in series with the input of the transformer 23a.

 It is easy to understand that in the third embodiment, the input impedance of the matching network is:

 2

Z ₀ = " R + j{n X —— + 3⁄4 ) Similarly, after impedance matching, the turns ratio of the transformer is "real""^ is the RF power supply

； 射频电源 10的频率为 co_m, 第一 电 容 232b 的 电 容值为 C_232b,_m , 且虚部 满 足 以 下公式 ： 210 constant output impedance R ₁₀ , therefore,

The frequency of the RF power source 10 is co _m , the capacitance value of the first capacitor 232b is C _232b , _m , and the imaginary part satisfies the following formula: 2

m ² X ^ + _m L _231b = 0

m, the formula can be used to obtain the relationship between 0) „ ₁ and C _232b , _m . Thus, the controller 21 can be used to adjust the RF power source 10, the transformer 23a and the first capacitor 232b to achieve impedance matching. Similar to the adjustment method disclosed in the first embodiment, it will not be described again here.

 In the fourth embodiment of the invention shown in Figure 6, both the inductor 231b and the first capacitor 232b are connected in series at the input of the transformer 23a. At this point, the input impedance of the matching network is:

Z ₀ = n ² R + j(n ² X ^ + <3⁄4 )

 ^0^2326,0 Similarly, after impedance matching, the turns ratio of the transformer is "real part"" ^ is the RF power supply

； 射频电源 10的频率为 co_m, 第一 n_m ²X —— + co_mL₀ = 0 电容 232b的电容值为 C_232b,_m,且虚部满足以下公式： ^ω"^ , 有该公式可以得出 ₀)„₁和 C_232b,_m之间的关系。从而可以利用控制器 21调节射 频电源 10、 变压器 23a和第一电容 232b, 以实现阻抗匹配。 具体调节方式 与第一种实施方式中的调节方式类似， 这里不再赘述。 10 constant output impedance R ₁₀ , therefore,

The frequency of the RF power supply 10 is co _m , the first n _m ² X —— + co _m L ₀ = 0 The capacitance value of the capacitor 232b is C _232b , _m , and the imaginary part satisfies the following formula: ^ω "^ , which has the formula It can be concluded that the relationship between ₀ ) „ ₁ and C _232b , _m . Thereby, the RF power source 10, the transformer 23a and the first capacitor 232b can be adjusted by the controller 21 to achieve impedance matching. The specific adjustment mode is similar to the adjustment mode in the first embodiment, and details are not described herein again.

 In a fifth embodiment of the present invention, as shown in FIG. 7, the impedance tunable elements 23b are both disposed at the output end of the transformer 23a, and the impedance tunable element 23b includes a second capacitor 233b and a third capacitor 234b, The second capacitor 233b is a tunable capacitor, and the second capacitor 233b is connected in parallel with the plasma chamber 30, and the third capacitor 234b is connected in series with the plasma chamber 30. The matching network at this time is

"L" type network.

 When the equivalent impedance of the plasma chamber 30 is + · Ζ '^, the admittance of the portion ^ on the right side of the transformer in Fig. 7 is:

1 R . ₍ P

n The input admittance Y ₀ of the matching network is: RP

° ~ n ² (R ² + P ² ) ^J n ^{2 0 233} R ² + P ²

Ρ = ω _η ∑ —

 Where ^0^2346,0 .

 R

The real part of the input admittance Y ₀ of the matching network is " ² ( ^{2 + ρ2} ), the input admittance of the matching network Υ ₀丄^ c ^ρ )

The imaginary part is ^233Μ — 7? ² + Ρ ² . Similarly, after impedance matching, the turns ratio of the transformer is,

 R

The real part "C^ + ² " is the reciprocal of the constant output impedance R _{1 ()} of the RF power source 10, and the imaginary part is satisfied.

1 p _m

The following formula: "According to the above two formulas, the relationship between ( _3⁄41 and c _233b , _m can be calculated. Thus, the controller 21 can be used to adjust the RF power source 10, the transformer 23a and the third capacitor 234b to achieve impedance matching. The manner is similar to the adjustment method in the first embodiment, and details are not described herein again.

 Corresponding to the radio frequency power system of the present invention, as shown in FIG. 8, a method for impedance matching using a radio frequency power system is provided. The radio frequency power system includes a radio frequency power source electrically connected to the radio frequency power source and the plasma chamber. An automatic impedance matching device, wherein the frequency of the radio frequency power source is adjustable between a minimum predetermined frequency and a maximum predetermined frequency, the automatic impedance matching method comprising:

Step 100: Acquire an equivalent impedance of the predetermined plasma chamber by using an automatic impedance matching device, and calculate an initial input impedance of the matching network. Step 200: Adjust a frequency of the RF power source, and adjust by using the automatic impedance matching device. The input impedance of the network is matched such that the input impedance of the matching network is equal to the constant output impedance of the RF power source. Since the adjustment range of the RF power source is large, when the RF power supply provided by the present invention is used for automatic impedance matching, the frequency of the RF power source can be adjusted to adjust the input impedance of the matching network to the vicinity of the matching impedance, and then fine-tuned. Automatic impedance matcher to match the input of the network The impedance is equal to the constant output impedance of the RF power supply, which further reduces the time required for impedance matching.

 It should be understood that the radio frequency power system described herein may be the above-described radio frequency power system provided in the present invention.

 Where the automatic impedance matcher includes an impedance sensor, a controller, and an actuator: the step 100 includes detecting, by the impedance sensor, an initial input impedance of the matching network and an initial frequency of the RF power source, and The initial input impedance of the matching network and the initial frequency of the radio frequency power source are sent to the controller, and the initial input impedance of the matching network is calculated by the controller;

 The step 200 includes utilizing the controller to adjust a frequency of the radio frequency power source and control an impedance of the actuator in accordance with an initial input impedance of the matching network.

 In the case where the actuator includes an impedance tunable element and a transformer having an adjustable turns ratio, as shown in FIG. 9, the step 200 includes:

 Step 210: Adjust a turns ratio of the transformer such that a real part of the impedance value of the input impedance of the matching network is equal to a constant output impedance of the RF power source;

 Step 220: Adjust an impedance of the impedance tunable component and a frequency of the RF power source such that an imaginary part of an impedance value of an input impedance of the matching network is zero.

 It can be understood that, in practical applications, the order of the above steps 210 and 220 may not be limited.

 Specifically, the step 220 includes:

 Step 221: Determine a matching frequency of the RF power source when an input impedance of the matching network is equal to a constant output impedance of the RF power source according to a relationship between the matching initial impedance and an initial RF frequency of the RF power source. ;

 Step 222: Adjust the impedance tunable component such that an input impedance of the matching network is equal to a constant output impedance of the RF power source.

How to specifically match the initial impedance and according to the above description has been given in the first embodiment above. The relationship between the initial radio frequencies of the radio frequency power source determines a matching frequency of the radio frequency power source when the input impedance of the matching network is equal to the constant output impedance of the radio frequency power source, and details are not described herein again.

 It is to be understood that the above embodiments are merely illustrative embodiments employed to illustrate the principles of the invention, but the invention is not limited thereto. Various modifications and improvements can be made by those skilled in the art without departing from the spirit and scope of the invention. These modifications and improvements are also considered to be within the scope of the invention.

Claims

claims 1. A radio frequency power supply system. The radio frequency power supply system includes a radio frequency power supply and an automatic impedance matcher electrically connected between the radio frequency power supply and the plasma chamber. It is characterized in that the frequency of the radio frequency power supply can be at a minimum predetermined frequency. and the maximum predetermined frequency. By adjusting the frequency of the radio frequency power supply and adjusting the input impedance of the matching network through the automatic impedance matching device, the input impedance of the matching network can be made equal to the constant output impedance of the radio frequency power supply. 2. The radio frequency power supply system according to claim 1, characterized in that the automatic impedance matching device includes an impedance sensor, a controller and an actuator, and the impedance sensor is used to detect the initial impedance of the actuator and the The initial frequency of the radio frequency power supply and the initial impedance of the actuator and the initial frequency of the radio frequency power supply are sent to the controller. The controller can determine the initial impedance of the actuator and the initial frequency of the radio frequency power supply. The frequency and the equivalent impedance of the plasma chamber are used to calculate the initial input impedance of the matching network, and the frequency of the radio frequency power supply and the impedance of the control actuator are adjusted according to the initial input impedance. 3. The radio frequency power supply system according to claim 2, characterized in that the actuator includes an impedance adjustable element and a transformer with an adjustable turns ratio, and the matching network can be adjusted by adjusting the turns ratio of the transformer. The real part of the impedance value of the input impedance, and the imaginary part of the impedance value of the input impedance of the matching network can be adjusted by adjusting the impedance of the impedance adjustable element. 4. The radio frequency power supply system according to claim 3, wherein the impedance adjustable element includes a first capacitor and an inductor, the first capacitor and the inductor are connected in series with the plasma chamber, and the first capacitor and the inductor are connected in series with the plasma chamber. At least one of a capacitor and the inductor is adjustable. 5. The radio frequency power supply system according to claim 3, wherein the impedance adjustable element includes a first capacitor and an inductor, and the first capacitor and the inductor are both connected in series to the transformer. At least one of the input terminal, the first capacitor and the inductor is adjustable. 6. The radio frequency power supply system according to claim 3, characterized in that: the impedance adjustable components are arranged at the output end of the transformer, and the impedance adjustable components include a second capacitor and a third capacitor, so The second capacitor is an adjustable capacitor, and the second capacitor is connected in parallel with the plasma chamber, and the third capacitor is connected in series with the plasma chamber. 7. A method of impedance matching using a radio frequency power supply system. The radio frequency power supply system includes a radio frequency power supply and an automatic impedance matcher electrically connected between the radio frequency power supply and a plasma chamber. The radio frequency power supply system is characterized in that: The frequency of the power supply can be adjusted between the minimum predetermined frequency and the maximum predetermined frequency, and the automatic impedance matching method includes: Step 100: Use the automatic impedance matching device to detect and obtain the predetermined equivalent impedance of the plasma chamber, and calculate the initial input impedance of the matching network; Step 200: Adjust the frequency of the radio frequency power supply, and use the automatic impedance matching device to adjust the input impedance of the matching network so that the input impedance of the matching network is equal to the constant output impedance of the radio frequency power supply. 8. The method according to claim 7, characterized in that the automatic impedance matching device includes an impedance sensor, a controller and an actuator; The step 100 includes using the impedance sensor to detect the initial input impedance of the matching network and the initial frequency of the radio frequency power supply, and sending the initial input impedance of the matching network and the initial frequency of the radio frequency power supply to the A controller that uses the controller to calculate the initial input impedance of the matching network; The step 200 includes using the controller to adjust the frequency of the radio frequency power supply and control the impedance of the actuator according to the initial input impedance of the matching network. 9. The method according to claim 8, characterized in that the actuator includes an impedance Adjustable elements and adjustable turns ratio transformers; The steps 200 include: adjusting the turns ratio of the transformer so that the real part of the impedance value of the input impedance of the matching network is equal to the constant output impedance of the radio frequency power supply; and The impedance of the adjustable impedance element and the frequency of the radio frequency power supply are adjusted so that the imaginary part of the impedance value of the input impedance of the matching network is zero. 10. The method according to claim 9, characterized in that: adjusting the impedance of the impedance adjustable element and the frequency of the radio frequency power supply so that the imaginary part of the impedance value of the input impedance of the matching network is Zero, including: Step 221: Determine the matching frequency of the radio frequency power supply when the input impedance of the matching network is equal to the constant output impedance of the radio frequency power supply based on the relationship between the matching initial impedance and the initial radio frequency of the radio frequency power supply. ; Step 222: Adjust the impedance adjustable component so that the input impedance of the matching network is equal to the constant output impedance of the radio frequency power supply.