KR102369880B1 - Radio frequency generator capable of monitoring dual outputs - Google Patents

Abstract

A high-frequency generator having a dual output monitoring function according to the present invention includes: a high-frequency amplifier configured to amplify a DC voltage of a predetermined level and output first and second amplified high-frequency signals; a combiner configured to output a high frequency power signal by combining the first high frequency amplified signal and the second high frequency amplified signal; a high-frequency sensor disposed on the output side of the combiner, configured to detect an electrical signal flowing to the output side of the combiner and output an electrical detection signal; a controller configured to output a switching control signal using an externally applied control signal and the electrical detection signal; a switch disposed between the combiner and the plasma chamber and controlled by the switching control signal to provide the high frequency power signal to first and second output terminals; and a state monitoring unit configured to monitor an operating state of the switch by detecting first and second high frequency power output signals respectively provided to the first and second output terminals of the switch.

Description

High-frequency generator with dual output monitoring

The present invention relates to a high-frequency generator, and more particularly, to a high-frequency generator having a dual output monitoring function.

Plasma etching is frequently used, for example, in semiconductor manufacturing. In plasma etching, it is accelerated by an electric field to etch exposed surfaces on a substrate. The electric field is generated according to the high frequency power signals generated by the high frequency generator of the high frequency power system. The high-frequency power signals generated by the high-frequency generator are precisely controlled to efficiently perform plasma etching.

A high frequency power system may include a high frequency generator, a matching network, and a load such as a plasma chamber. High frequency power signals are used to load a variety of components including, but not limited to, integrated circuits (ICs), solar cells, compact disks (CDs), and/or digital versatile (or video) disks (DVDs). used to drive Load cables with broadband mismatched loads (eg, mismatched resistor termination), narrowband mismatched loads (eg, two-element matching network), and resonator loads. may include

1 shows a high-frequency plasma supply for generating a plasma power level for supplying a plasma load 7 according to the prior art.

A high-frequency plasma supply apparatus according to the prior art includes an AC-DC converter 1, a first high-frequency generator 2, a second high-frequency generator 3, a combiner 4, a high-frequency sensor 5, and It includes a controller (6).

The AC-DC converter 1 converts a commercial AC voltage into a DC voltage of a predetermined level.

The first high frequency generator 2 and the second high frequency generator 3 each generate a high frequency signal using the DC voltage output from the AC-DC converter 1 .

The combiner 4 combines the high frequency signals output from the first high frequency generator 2 and the second high frequency generator 3 .

The high frequency sensor 5 detects a forward high frequency signal output from the combiner 4 to the plasma load 7 or a reverse high frequency signal output from the plasma load 7 to the combiner 4 .

The controller 6 is a control signal for controlling the AC-DC converter 1 , the first high frequency generator 2 , and the second high frequency generator 3 using the detection signal output from the high frequency sensor 5 . to create

On the other hand, as shown in Figure 1, the prior art high-frequency plasma supply device, when supplying plasma to a plasma chamber as a load, supplies high-frequency power only to one electrode of the plasma chamber, and the other side of the plasma chamber is connected to the ground side. is the structure However, with the advancement of process technology, there is a demand to generate plasma of various sizes in a plasma chamber.

Therefore, there is a need to provide a high-frequency generator having a dual output capable of supplying a high-frequency power signal to both ends of the plasma chamber.

Korean Patent Registration No. 10-0842243 Method for controlling or adjusting power output of RF plasma supply device and RF plasma supply device

However, since the load impedance changes due to the change of the forward power and the reverse power, there is a possibility that an error may occur in detecting the operation state of the switch that selectively outputs the high frequency output signal output from the combiner to the two loads.

Accordingly, an object of the present invention is to provide a high-frequency generator that is robust to changes in load impedance and has a function of monitoring dual outputs.

A high-frequency generator having a dual output monitoring function according to the present invention includes: a high-frequency amplifier configured to amplify a DC voltage of a predetermined level and output first and second amplified high-frequency signals; a combiner configured to output a high frequency power signal by combining the first high frequency amplified signal and the second high frequency amplified signal; a high-frequency sensor disposed on the output side of the combiner, configured to detect an electrical signal flowing to the output side of the combiner and output an electrical detection signal; a controller configured to output a switching control signal using an externally applied control signal and the electrical detection signal; a switch disposed between the combiner and the plasma chamber and controlled by the switching control signal to provide the high frequency power signal to first and second output terminals; and a state monitoring unit configured to monitor an operating state of the switch by detecting first and second high frequency power output signals respectively provided to the first and second output terminals of the switch.

Preferably, the switch is implemented as a mechanical switch or an electronic switch, and the first and second high frequency power output signals output through the first and second output terminals of the switch are respectively applied to the upper or lower electrode of the plasma chamber. alternately supplied to

Preferably, the state monitoring unit detects first and second high frequency power from the first and second high frequency power output signals, respectively, and outputs first and second high frequency power detection signals, respectively. power detector; first and second impedance matchers configured to respectively match impedances between the first and second high-frequency power detectors and the first and second comparators at the rear end; a reverse signal blocking unit including first and second one-way elements configured to pass the first and second high-frequency power detection signals to the first and second comparators at the rear end in one direction; a noise interference canceller including third and fourth one-way elements each forward coupled from the first and second one-way elements to a reference voltage terminal to which a reference voltage is provided; and a comparator including a first comparator comparing the output voltage of the first unidirectional element with the reference voltage, and a second comparator comparing the output voltage of the second unidirectional element with the reference voltage.

Preferably, the first and second high frequency power detectors include a first microstrip transformer connected to a first output terminal of the switch, and a second microstrip transformer connected to a second output terminal of the switch. .

Preferably, the first to fourth unidirectional elements may be implemented as diodes.

According to the high-frequency generator of the present invention, it is possible to accurately detect the operation state of a switch that selectively outputs a high-frequency output signal output from the combiner to two loads even when the load impedance changes due to changes in forward power and reverse power. . In addition, the high-frequency generator of the present invention can supply high-frequency power signals to both electrodes of the plasma chamber, one high-frequency generator can provide two high-frequency power signals, and selectively provide two high-frequency power signals to the plasma chamber Plasma generated inside can be precisely controlled. In addition, by providing two high-frequency power signals with one generator, the size of the generator can be significantly reduced, thereby significantly reducing the manufacturing cost.

1 is a block diagram of a high-frequency generator according to the prior art;
2 is an overall block diagram of a high-frequency generator having a dual output monitoring function according to an embodiment of the present invention;
3 is a dual output monitoring circuit diagram according to an embodiment of the present invention;
4 is a waveform diagram of each part in the case of having a fixed reference voltage;
5 is a waveform diagram of each part in the case of having a fluctuating reference voltage, and
6 is a reference voltage increase waveform diagram according to an increase in output voltage.

Additional objects, features and advantages of the present invention may be more clearly understood from the following detailed description and accompanying drawings.

Prior to the detailed description of the present invention, the present invention can make various changes and can have various embodiments, and the examples described below and shown in the drawings are not intended to limit the present invention to specific embodiments. No, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

When a component is referred to as being “connected” or “connected” to another component, it may be directly connected or connected to the other component, but it is understood that other components may exist in between. it should be On the other hand, when it is said that a certain element is "directly connected" or "directly connected" to another element, it should be understood that the other element does not exist in the middle.

The terms used herein are used only to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present specification, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

In addition, terms such as "...unit", "...unit", "...module", etc. described in the specification mean a unit that processes at least one function or operation, which includes hardware or software or hardware and It can be implemented by a combination of software.

In addition, in the description with reference to the accompanying drawings, the same components are given the same reference numerals regardless of the reference numerals, and the overlapping description thereof will be omitted. In describing the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

In addition, throughout this specification, when a step is located “on” or “before” another step, this means not only a case in which a step is in a direct time-series relationship with another step, but also a step of mixing after each step and Likewise, the order of two stages includes the same rights as in the case of an indirect time series relationship in which the time series order can be changed.

Hereinafter, a high-frequency generator having a dual output according to an embodiment of the present invention will be described in detail.

2 is an overall block diagram of a high-frequency generator having a dual output monitoring function according to an embodiment of the present invention.

The high-frequency generator having a dual output monitoring function according to an embodiment of the present invention includes an AC-DC converter 110 , a smoothing part 115 , a high-frequency amplifier 117 , a combiner 150 , and a high-frequency sensor 160 . ), a switch 170 , a plasma chamber 180 , and a controller 190 .

The AC-DC converter 110 is controlled by the voltage control signal Vcon output from the controller 190 to rectify and output the commercial three-phase AC voltage to a DC voltage of a predetermined level.

The smoothing unit 115 smoothes the DC voltage output from the AC-DC converting unit 110 .

The high frequency amplification unit 117 according to an embodiment of the present invention includes a high frequency power conversion unit 127 , a coupling transformer 137 , and a resonance network 147 .

The high frequency power converter 127 amplifies the DC voltage of a predetermined level output from the AC-DC converter 110 to generate a high frequency signal of a pulse waveform. The high frequency power converter 127 may operate two or more high frequency power converters in parallel to generate voltages and frequencies according to various load conditions. According to an embodiment of the present invention, the high-frequency power converter 127 uses two high-frequency power converters 120 and 125 . The first high frequency power converter 120 and the second high frequency power converter 125 are respectively controlled by the first amplification control signal Pcon1 and the second amplification control signal Pcon2 output from the controller 190 , and the first high frequency power converter 125 , respectively. The phase of the converted signal v1 and the phase of the second high frequency converted signal v2 may be the same as or different from each other in phase.

Combination transformer 137 includes a first coupling transformer 130 and a second coupling transformer 135 . The first coupling transformer 130 induces a first high frequency converted signal of the pulse waveform output from the first high frequency power converter 120 to the secondary side, and the second coupling transformer 135 is a second high frequency power converter ( 125) and induces the second high-frequency converted signal of the pulse waveform output to the secondary side. The coupling transformer 137 electrically insulates the primary side and the secondary side, thereby preventing an electric shock accident when the user touches the plasma chamber.

The resonant network 147 includes first and second resonators 140 and 145, and each of the first and second resonators 140 and 145 includes an inductor and a capacitor coupled in series and parallel, and a transformer for coupling. From the high-frequency converted signal induced on the secondary side of (137), a sinusoidal high-frequency amplified signal having a predetermined resonant frequency is output. Here, the first resonance network 140 outputs the first high frequency amplified signal vR1 , and the second resonance network 250 outputs the second high frequency amplified signal vR2 . Meanwhile, the phase of the first amplified high frequency signal vR1 and the phase of the second amplified high frequency signal vR2 may be the same as or different from each other. Here, the difference in the phase of the first high frequency amplified signal vR1 and the second high frequency amplified signal vR2 means that the phase of the second high frequency amplified signal vR2 is different from that of the first high frequency amplified signal vR1. can be behind or ahead. According to an embodiment, the resonance frequency of the high frequency amplified signal may be 13.56 MHz.

Also, although not shown, the high frequency amplifier according to another embodiment of the present invention may be implemented as a linear amplifier that directly generates a high frequency amplified signal from a DC voltage without using a transformer.

The combiner 150 may be configured as a 3dB coupler. The combiner 150 combines the first high frequency amplified signal vR1 and the second high frequency amplified signal vR2 to output the combined high frequency power signal. When the phase of the first high frequency amplified signal vR1 is 90 degrees ahead of the phase of the second high frequency amplified signal vR2, the high frequency power signal may be mostly output to a load-side terminal (not shown). When the phase of the first high frequency amplified signal vR1 is 90 degrees behind the phase of the second high frequency amplified signal vR2, the high frequency power signal may be mostly output to the termination terminal (not shown). In addition, when the phase of the first amplified high frequency signal vR1 and the phase of the second amplified high frequency signal vR2 are the same, the high frequency power signal may be output in half to the load-side terminal and the terminal terminal.

In this way, by controlling the phase of the first high frequency converted signal v1 and the phase of the second high frequency converted signal v2, the phase of the first high frequency amplified signal vR1 and the phase of the second high frequency converted signal vR2 are adjusted Accordingly, the magnitude of the high-frequency power signal output to the plasma chamber 180 may be adjusted.

The high frequency sensor 160 is disposed between the combiner 150 and the plasma chamber 180 , detects an electrical signal flowing between the combiner 150 and the plasma chamber 180 , and outputs an electrical detection signal. Here, the electrical detection signal includes a detection current value Is, a detection voltage value Vs, a forward power supplied from the combiner 150 to the plasma chamber 180 PFWD, and a combine from the plasma chamber 180 . It may be at least one or more of the reverse power PREF reflected to you 150 .

The controller 190 uses a control signal Scon applied from the outside and an electrical detection signal output from the high frequency sensor 160 to generate a voltage control signal Vcon, a first amplification control signal Pcon1, and a second amplification control signal. (Pcon2) and a switching control signal (Ssw) are generated.

The switch 170 is controlled by the switching control signal Ssw output from the controller 190 to convert the high frequency power signal output from the combiner 150 to the first high frequency power output signal SA or the second high frequency power output signal. (SB) can be separated and printed. Here, according to the present invention, the plasma chamber 180 is grounded to the chamber wall.

According to an embodiment of the present invention, the switch 170 may be implemented as a mechanical switch. The switch 170 may have first and second output terminals. For example, the switch 170 may be implemented by a single relay using the switching control signal Ssw output from the controller 190 as a driving signal. A relay may have an A contact and a B contact.

Also, according to another embodiment of the present invention, the switch 170 may be implemented as two electronic switches. For example, the two electronic switches may be controlled by the switching control signal Ssw output from the controller 190 to alternately switch. Meanwhile, according to the present invention, since it is obvious to those skilled in the art that it is not limited to two electronic switches and can be implemented using two or more electronic switches, a detailed description thereof will be omitted.

Meanwhile, although not shown, a first impedance matching unit is arranged between the switch 170 and an upper electrode of the plasma chamber, and a second impedance matching unit is arranged between the switch 170 and a lower electrode of the plasma chamber.

3 is a circuit diagram of dual output monitoring according to an embodiment of the present invention.

The dual output monitoring circuit according to an embodiment of the present invention includes a relay unit 210, a high frequency power detection unit 220, 225, an impedance matching unit 230, 235, a reverse signal blocking unit 240, 245, a noise interference It includes a removal unit 250 and comparison units 260 and 265 . Here, the relay unit 210 is an embodiment of the switch 170 shown in FIG. 2 .

The relay unit 210 is controlled by the switching control signal Ssw output from the controller 190 to transmit the first high frequency power output signal SA through the A contact and the second high frequency power output signal SB through the B contact. ) is output.

The high frequency power detection units 220 and 225 detect individual high frequency power output from the relay unit 210 . The high frequency power detection units 220 and 225 include a first high frequency power detector 220 connected to the A contact of the relay unit 210 and a second high frequency power detector 225 connected to the B contact of the relay unit 210 . include The first high frequency power detector 220 uses a first microstrip transformer connected to the A contact of the relay unit 210, and the high frequency of the first high frequency power output signal SA from the secondary side of the first microstrip transformer The power is detected and a first high frequency power detection signal is output. The second high frequency power detector 225 uses a second microstrip transformer connected to the B contact of the relay unit 210 , and the high frequency of the second high frequency power output signal SB from the secondary side of the second microstrip transformer The power is detected and a second high frequency power detection signal is output.

The impedance matching units 230 and 235 are disposed between the high frequency power detection units 220 and 225 and the comparator 260 , and match the impedances of the high frequency power detection units 220 and 225 and the comparison unit 260 . The impedance matching units 230 and 235 include a first impedance matcher 230 and a second impedance matcher 235 . The first impedance matcher 230 includes a resistor and a capacitor disposed between the output side of the first high frequency power detector 220 and the ground, and compares the impedance between the first high frequency power detector 220 and the first comparator 260 . match The second impedance matcher 235 includes a resistor and a capacitor disposed between the output side of the second high frequency power detector 225 and the ground, and the impedance between the second high frequency power detector 225 and the second comparator 265 . match

The reverse signal blocking units 240 and 245 include a first one-way element 240 and a second one-way element 245 connected in a forward direction to the first and second impedance matchers 230 and 235, respectively, and a high-frequency power detection unit The individual high-frequency power detection signals output from 220 and 225 are passed to the comparison units 260 and 265 at the rear end, and signals flowing in the reverse direction are blocked. Here, the first unidirectional element 240 and the second unidirectional element 245 may be implemented as diodes.

The noise interference removing unit 250 includes a third one-way element 251 that is forward coupled from the output terminals of the first one-way element 240 and the second one-way element 245 to the reference voltage terminal to which the reference voltage Vref is provided, and A fourth one-way element 253 is included. Here, the third one-way element 251 and the fourth one-way element 253 are elements having a forward voltage drop, and may be, for example, diodes. When the output voltage Va of the first one-way element 240 is applied to the anode terminal of the third one-way element 251, the reference voltage Vref applied to the cathode terminal of the third one-way element 251 is It has a potential lower than the output voltage Va of the device 240 by a forward voltage drop.

The comparators 260 and 265 include a first comparator 260 and a second comparator 265 . The first comparator 260 compares the output voltage of the first unidirectional element 240 with the reference voltage Vref to output a first comparison signal V1. That is, when the output voltage of the first unidirectional element 240 is higher than the reference voltage Vref, the comparison signal Vo of "H" level is output. The second comparator 265 compares the output voltage of the second one-way element 245 with the reference voltage Vref to output a second comparison signal V2. That is, when the output voltage of the second one-way element 245 is higher than the reference voltage Vref, the comparison signal Vo of "H" level is output.

However, an unwanted noise voltage may be included in the output Va of the first unidirectional element 240 or the output Vb of the second unidirectional element 245 due to various factors such as a change in load impedance or signal interference.

4 is a waveform diagram of each part in the case of having a fixed reference voltage, when the level of the reference voltage is fixed. As such, when the level of the reference voltage Vref is fixed, the output voltage Va of the first unidirectional element 240 is higher than the reference voltage Vref, so that the first comparison signal V1 of “H” level is output Meanwhile, the second comparison signal V2 of “H” level is output at an instant when the output voltage Vb of the second unidirectional element 245 is also higher than the reference voltage Vref. Accordingly, an error occurs in detecting the relay operation.

Accordingly, the dual output monitoring circuit according to an embodiment of the present invention can prevent an error when detecting a relay operation by having the noise interference removing unit 250 configured as shown in FIG. 3 .

5 is a waveform diagram of each part in the case of having a variable reference voltage. When there is no output voltage of the first one-way element 240 and the second one-way element 245, the reference voltage Vref maintains a predetermined level. Afterwards, when the output voltage Va of the first unidirectional element 240 rises to a predetermined potential, the reference voltage Vref becomes the output voltage Va of the first unidirectional element 240 under the influence of the third unidirectional element 251 . It rises to a lower potential by the more forward voltage drop.

In this case, even if the noise voltage is inserted into the output Vb of the second unidirectional element 245, the reference voltage Vref level is in a state in which the level of the reference voltage Vref is increased, so the output V2 of the second comparator 265 can maintain the “L” level state. there is.

6 is a waveform diagram showing a reference voltage increase according to an increase in the output voltage. When the output voltage Va of the first unidirectional element 240 increases, the reference voltage Vref also maintains a potential difference equal to the forward voltage drop. rises

Although the above-described embodiments have been described with reference to the limited drawings, a person skilled in the art may apply various technical modifications and variations based on the above. For example, the described techniques are performed in an order different from the described method, and/or the described components of the system, structure, apparatus, circuit, etc. are combined or combined in a different form than the described method, or other components Or substituted or substituted by equivalents may achieve an appropriate result.

The embodiments described in this specification and the accompanying drawings are merely illustrative of some of the technical ideas included in the present invention. Accordingly, since the embodiments disclosed in the present specification are for explanation rather than limitation of the technical spirit of the present invention, it is obvious that the scope of the technical spirit of the present invention is not limited by these embodiments. Modifications and specific embodiments that can be easily inferred by those skilled in the art within the scope of the technical spirit included in the specification and drawings of the present invention should be interpreted as being included in the scope of the present invention.

110: AC-DC conversion unit
115: smooth part
120, 125: high-frequency power amplification unit
130, 135: a transformer for coupling
140, 145: resonant network
150: combiner
160: high frequency sensor
170: switch
180: plasma chamber
190: controller
210: relay unit
220, 225: high-frequency power detection unit
230, 235: impedance matching unit
240, 245: reverse signal blocking unit
250: noise interference cancellation unit
260, 265: comparison unit

Claims (5)

a high frequency amplifier configured to amplify a DC voltage of a predetermined level and output first and second high frequency amplified signals; a combiner configured to output a high frequency power signal by combining the first high frequency amplified signal and the second high frequency amplified signal; a high-frequency sensor disposed on the output side of the combiner, configured to detect an electrical signal flowing to the output side of the combiner and output an electrical detection signal; a controller configured to output a switching control signal using an externally applied control signal and the electrical detection signal; a switch disposed between the combiner and the plasma chamber and controlled by the switching control signal to provide the high frequency power signal to first and second output terminals; and a state monitoring unit configured to monitor an operating state of the switch by detecting first and second high frequency power output signals respectively provided to the first and second output terminals of the switch;
The state monitoring unit may include: first and second high frequency power detectors for detecting first and second high frequency power from the first and second high frequency power output signals, respectively, and outputting first and second high frequency power detection signals, respectively; first and second impedance matchers configured to respectively match impedances between the first and second high frequency power detectors and the first and second comparators at the rear end; a reverse signal blocking unit including first and second unidirectional elements configured to pass the first and second high frequency power detection signals in one direction toward the first and second comparators at the rear end; a noise interference removing unit including third and fourth one-way elements each forward coupled from the first and second one-way elements to a reference voltage terminal to which a reference voltage is provided; and a first comparator comparing the output voltage of the first one-way element with the reference voltage, and a second comparator comparing the output voltage of the second one-way element with the reference voltage.
A high-frequency generator with dual output monitoring that includes
The method according to claim 1,
The switch is implemented as a mechanical switch or an electronic switch, and the first and second high frequency power output signals output through the first and second output terminals of the switch are alternately supplied to upper and lower electrodes of the plasma chamber, respectively High frequency generator with dual output monitoring function, characterized in that.
delete The method according to claim 1,
The first and second high frequency power detectors include a first microstrip transformer connected to a first output terminal of the switch, and a second microstrip transformer connected to a second output terminal of the switch. A high-frequency generator with
5. The method according to claim 4,
A high frequency generator with a dual output monitoring function, characterized in that the first to fourth one-way elements are diodes.

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