WO2019171640A1

WO2019171640A1 - High-frequency power source device

Info

Publication number: WO2019171640A1
Application number: PCT/JP2018/036368
Authority: WO
Inventors: 岡田　健; 押田　善之; 藤本　直也
Original assignee: 株式会社日立国際電気
Priority date: 2018-03-09
Filing date: 2018-09-28
Publication date: 2019-09-12
Also published as: JP6922069B2; JPWO2019171640A1

Abstract

Provided is a high-frequency power source device that makes it possible to ascertain the status of a load, while also reducing the size and reducing the cost of the device. The high-frequency power source device is provided with: a high-frequency power source circuit; a detector provided to an output of the high-frequency power source circuit; a high-frequency path connected to an output of the detector; and a matching box that is connected to the high-frequency path and provides a high-frequency power source to an input of a load. The detector is able to acquire information about traveling waves/reflected waves. The high-frequency power source circuit calculates a load impedance by adding the impedance change component at the high-frequency path and the matching box to impedance information in a case where the high-frequency path onward is viewed from the output of the detector, such output calculated from the acquired information about the traveling waves/reflected waves.

Description

High frequency power supply

This disclosure relates to a high-frequency power supply device, and in particular, can be applied to a high-frequency power supply device that can grasp a load state.

High frequency power supply devices are used to generate plasma and lasers in semiconductor manufacturing equipment and laser processing machines. As this type of high-frequency power supply device, for example, there is a proposal of JP-A-2016-178446 (Patent Document 1).

JP 2016-178446 A

The high frequency power supply apparatus examined by the present inventors prior to the present disclosure includes a high frequency power supply circuit, a detector (high frequency power supply side) provided on the output side of the high frequency power supply circuit, a high frequency path, a matching unit, and a matching unit. The detector (matching device side) connected to the input / output of, and a load. In this high-frequency power supply device, it is necessary to insert a detector (matching device side) also at the input or output of the matching device in order to monitor the impedance of the load, which may be disadvantageous in terms of cost and size. .

The problem of the present disclosure is to provide a high-frequency power supply device that can grasp the load status while realizing downsizing and cost reduction.

Other issues and novel features will become clear from the description of the present specification and the accompanying drawings.

The outline of typical ones of the present disclosure will be briefly described as follows.

That is, the high frequency power supply device includes a high frequency power supply circuit, a detector provided at the output of the high frequency power supply circuit, a high frequency path connected to the output of the detector, a high frequency path connected to the high frequency path, And a matching unit for supplying power. The detector can acquire information on traveling waves and reflected waves. The high-frequency power supply circuit uses the high-frequency path and the matching unit to determine impedance information when the high-frequency path is viewed from the output of the detector calculated from the acquired traveling wave and reflected wave information. The load impedance is calculated by adding the impedance change.

According to the above high-frequency power supply device, it is possible to grasp the load state while achieving downsizing and cost reduction.

It is a schematic block diagram which shows the structure of the high frequency power supply apparatus which concerns on a comparative example. It is a schematic block diagram which shows the structure of the high frequency power supply device which concerns on an Example. It is the schematic about the correction | amendment of the impedance which concerns on an Example. It is the schematic of the calculation of the impedance correction which concerns on an Example.

Hereinafter, comparative examples and examples will be described with reference to the drawings. However, in the following description, the same components may be denoted by the same reference numerals and repeated description may be omitted. In addition, although drawing may be represented typically compared with an actual aspect in order to clarify description more, it is an example to the last and does not limit the interpretation of this invention.

First, a high-frequency power supply device according to a technique (hereinafter referred to as a comparative example) examined by the inventors of the present application prior to the present disclosure will be described with reference to FIG.

The high frequency power supply device 100 includes a high frequency power supply circuit 1, a detector 2 provided on the output side of the high frequency power supply circuit 1, a high frequency path 3, two detectors 4, a matching device 5, and a load 6. ing. The detector 4 is provided on the input side of the matching unit 5 and the output side of the matching unit 5.

The high frequency power supply circuit 1 is a high frequency power source that amplifies the high frequency generated in the oscillation circuit and outputs high frequency power.

The detector 2 is a circuit block that is connected to the output of the high-frequency power supply circuit 1 and can detect information on traveling waves and reflected waves used for the control of the matching unit 5 and output power control.

The high frequency path 3 is a block such as a high frequency cable or a connector for supplying the output of the high frequency power supply circuit 1 to the load 6.

The detector 4 is connected to the input / output of the matching unit 5 and is a circuit block for monitoring the impedance of the load 6 from information on traveling waves and reflected waves. The detector 4 may be provided at one of the input and output of the matching unit 5.

The matching unit 5 is an impedance matching circuit for matching the output impedance of the high-frequency power supply circuit 1 and the input impedance of the load 6, and is composed of a variable capacitor and a fixed coil. By adjusting the capacitance of the variable capacitor, This is a circuit block that performs impedance matching.

When the matching unit 4 is not provided, a reflected wave from the load 6 is generated, and only a part of the output power can be supplied to the load 6 and the power efficiency is lowered. In order to suppress the reflected wave, a matching unit 5 is required between the high-frequency power supply circuit 1 and the load 6.

The high frequency power supply device 100 shown in FIG. 1 has an automatic matching function that suppresses reflected waves by control from the high frequency power supply circuit 1 in order to prevent a reduction in power efficiency. The automatic alignment function will be briefly described.

The high frequency power supply circuit 1 starts output of high frequency power in response to an output ON instruction, and detects a traveling wave and a reflected wave of the high frequency output power with the detector 2. The high frequency power supply circuit 1 calculates a reflection coefficient from the detected level of the reflected wave, and controls the capacitance value of the variable capacitor of the matching unit 5 so that the level of the reflected wave becomes small.

(Impedance monitoring function in the high frequency power supply device 100 of FIG. 1)
In the high frequency power supply device 100, the detector 4 is provided at the input or output of the matching unit 5, and the load impedance is calculated from the traveling wave and the reflected wave detected by the detector 4 and displayed.

In addition, when the detector 4 is not provided at the input or output of the matching unit 5, there is a method in which the capacitance value of the variable capacitor at the time of completion of matching is linked to the impedance value of the load prepared in advance in the table.

However, in the high frequency power supply device 100, it is necessary to insert the detector 4 at the input or output of the matching unit 5 in order to monitor the impedance of the load 6, which may be disadvantageous in terms of cost and size. .

Also, if the load impedance is estimated from the capacitance of the variable capacitor, it is necessary to measure the relationship between the capacitance and impedance of the variable capacitor in advance. In addition, when element parameters such as the length of a variable capacitor, a coil, and a high frequency cable are changed, it is necessary to measure the impedance each time and reflect it in the table value.

Embodiments of the present invention will be described with reference to the drawings. FIG. 2 is a schematic configuration diagram showing the configuration of the high-frequency power supply device of the present invention.

The high frequency power supply device 10 includes a high frequency power supply circuit 1, a detector 2, a high frequency path 3, a matching unit 5, a current detector 7, and a load 6. The high frequency power supply device 10 is used for generating plasma and laser in, for example, a semiconductor manufacturing apparatus and a laser processing machine. The difference between the high-frequency power supply device 10 and the high-frequency power supply device 100 shown in FIG. 1 is that the high-frequency power supply device 10 has no detector 4 and a current detector 7 is added.

The high frequency power supply circuit 1 is a high frequency power source that amplifies the high frequency generated in the oscillation circuit and outputs high frequency power. The high frequency power supply circuit 1 is provided with an arithmetic circuit 1a for performing the arithmetic operation described in FIG. The high-frequency power supply circuit 1 is provided with a display device (not shown), and this display device can display the calculation result calculated by the calculation circuit 1a.

The detector 2 is a circuit block that is connected to the output of the high-frequency power supply circuit 1 and can detect information on traveling waves and reflected waves used for the control of the matching unit 5 and output power control. Information on the traveling wave and the reflected wave detected by the detector 2 is supplied to the arithmetic circuit 1a via the wiring LN1 indicated by a dotted line.

The high frequency path 3 is a block such as a high frequency cable or a connector for supplying the output of the high frequency power supply circuit 1 to the load 6, and is provided between the output of the detector 2 and the input of the matching unit 5.

The matching unit 5 is an impedance matching circuit for matching the output impedance of the high-frequency power supply circuit 1 and the input impedance of the load 6, and is composed of a variable capacitor and a fixed coil. By adjusting the capacitance of the variable capacitor, This is a circuit block that performs impedance matching. The value of the capacitance of the variable capacitor in the matching unit 5 is supplied to the arithmetic circuit 1a via the wiring LN1 indicated by the dotted line.

The newly added current detector 7 is a circuit block that is connected between the output of the matching unit 5 and the input of the load 6 and detects or monitors the value of the current input to the load 6. The current detector 7 can be measured by attaching, for example, a current sensor 71 such as a coil to a power cable or power wiring that supplies high-frequency power to the load 6. The current value detected by the current detector 7 is supplied to the high frequency power supply circuit 1 via the wiring LN2 indicated by a dotted line.

The high-frequency power supply device 10 has an automatic matching function for suppressing reflected waves by control from the high-frequency power supply circuit 1 in order to prevent a reduction in power efficiency. The high frequency power supply circuit 1 starts output of high frequency power in response to an output ON instruction, and detects a traveling wave and a reflected wave of the high frequency output power with the detector 2. The high-frequency power supply circuit 1 includes an automatic matching function that calculates the reflection coefficient from the detected reflected wave level and controls the value of the variable capacitor of the matching unit 5 so that the reflected wave level becomes smaller.

The high frequency signal generated by the high frequency power supply circuit 1 is supplied to the load 6. The load 6 dynamically varies depending on circumstances, and the matching unit 5 operates so that the high-frequency power supplied from the high-frequency power circuit 1 is supplied to the fluctuating load 6 without reflection, and the high-frequency power circuit 1 and the load 6 are operated. Impedance matching between.

For impedance matching between the high-frequency power supply circuit 1 and the load 6, information on traveling waves and reflected waves detected by the detector 2 is used, and the capacitance of the variable capacitor of the matching unit 5 is controlled so that the reflected waves become small. To do. The traveling wave information detected by the detector 2 is also used for output power control of the high frequency power supply circuit 1.

FIG. 3 is a schematic diagram for impedance correction. FIG. 4 is a schematic diagram of calculation for impedance correction. 3 and 4, illustration of the wiring LN1 and the wiring LN2 shown in FIG. 2 is omitted.

The information on the traveling wave and the reflected wave detected by the detector 2 is converted into impedance information by the arithmetic circuit 1a of the high frequency power supply circuit 1. This impedance information is impedance information (20) viewed from the output of the detector 2 (high frequency path 3 and subsequent) as shown in FIG.

The information to be obtained is the input impedance (30) of the load 6, but the difference between the impedance information (20) viewed from the output of the detector 2 (after the high-frequency path 3) and the input impedance (30) of the load 6 is This is the impedance change (40) of the high-frequency path 3, the matching unit 5, and the current detector 7 existing between the high-frequency power circuit 1 and the load 6.

Therefore, the impedance information (20) viewed from the output of the detector 2 (after the high-frequency path 3) is corrected using the impedance change (40) of the high-frequency path 3, the matching unit 5, and the current detector 7. Thus, the input impedance (30) of the load 6 can be calculated. This calculation is performed by causing the calculation circuit 1a of the high frequency power supply circuit 1 to execute a calculation program.

Among the impedance changes (30) of the high-frequency path 3, matching unit 5 and current detector 7 used for correction, the impedance of the high-frequency path 3 and current detector 7 is a known value. Moreover, fixed inductors other than the variable capacitors, parasitic inductor components, and the like in the matching unit 5 are also known values.

Since these known values are used as constants in the arithmetic program, even if the values change due to a change in the system of the high-frequency power supply circuit 1, the impedance change is measured once, and the constant values are measured using the measured constant values. By updating the table values described above, the calculation of the input impedance of the load 6 can be performed by the arithmetic circuit 1a without any problem.

Also, by comparing the calculated input impedance value of the load 6 with the current value monitored by the current detector 7, the accuracy of the load state monitoring can be ensured.

An example of the calculation of the arithmetic circuit 1a will be described with reference to FIG. As shown in FIG. 4, it is assumed that a variable capacitor C1, a fixed resistor L2, a parallel parasitic inductor L1, and a series parasitic inductor L3 exist in the matching unit 5 as an example. In this case, ZLr and ZLi of the input impedance 30 of the load 6 from Zr and Zi of the impedance 20 converted from the traveling wave and the reflected wave of the high-frequency power supply circuit 1 monitored by the detector 2 are the following 1) to 7): It can be calculated by the calculation described in 1.

Here, Zr represents the real part of the output impedance 20 of the high-frequency power supply circuit 1, and Zi represents the imaginary part of the output impedance 20 of the high-frequency power supply circuit 1. ZLr represents the real part of the input impedance 30 of the load 6, and ZLi represents the imaginary part of the input impedance 30 of the load 6.

1) Calculation of Zr and Zi admittance conversion (Yr1 and Yi1) is as follows.

Yr1 = Zr / (Zr × Zr + Zi × Zi)
Yi1 = (− 1 × Zi) / (Zr × Zr + Zi × Zi)
2) Calculation of admittance (Y (C + L)) of variable capacitor C1 + parasitic inductor L1 is as follows.

ω = 2πf
Y (C + L) = ((− 1) × ω × C1) / (ω × ω × L1 × C1))
3) Calculation of admittance (Yr2 and Yi2) is as follows.

Yr2 = Yr1
Yi2 = Yi1-Y (C + L)
4) Calculation of impedance transformation (Zr1 and Zi2) between Yr2 and Yi2 is as follows.

Zr1 = Yr2 / (Yr2 * Yr2 + Yi2 * Yi2)
Zi1 = (-1 * Yi2) / (Yr2 * Yr2 + Yi2 * Yi2)
5) Calculation of impedance (ZwL) of series inductor L2 is as follows.

ZwL = ω × L2
6) Calculation of the impedance (ZwL (parasitic)) of the parasitic inductor L3 is as follows.

ZwL (parasitic) = ω x L3
7) The calculation of the input impedance 30 (ZLr and ZLi) of the load 6 is as follows.

ZLr = Zr1
ZLi = Zi1-ZwL-ZwL (parasitic)
Therefore, the phase change of the high-frequency path 3 is changed from the output of the high-frequency power supply circuit 1 monitored by the detector 2 provided at the output of the high-frequency power supply circuit 1 (here, the output of the detector 2) to the impedance information (20). The impedance (40) at the input point of the load 6 can be calculated in a pseudo manner by adding the amount of change, 30 loss, and the impedance change (30) due to the C component and L component in the matching unit 5. The calculated impedance (40) can be displayed on a display device provided in the high-frequency power supply circuit 1, for example.

According to the embodiment, the high-frequency power supply device 10 includes a high-frequency power supply circuit 1 that generates a high frequency, and a matching unit 5 that is connected to the load 6 and matches the output of the high-frequency power supply circuit 1. Calculates the input impedance (40: Zlr, Zli) of the load 6 based on the output power control and automatic matching detector 2 and the capacitance C1 of the variable capacitor of the matching unit 5, the phase change of the known system, and the loss. Has an arithmetic circuit 1a. For this reason, even if the number of detectors 4 provided at the input or output of the matching unit 5 shown in FIG. 1 is reduced, the impedance (20) viewed from the output of the high-frequency power supply circuit 1 (the output of the detector 2) is used. The input impedance (40: Zlr, Zli) of the load 6 can be calculated. Therefore, there is an effect that the high frequency power supply device 10 can be reduced in size and cost.

Further, according to the embodiment, a simple current detector 7 is provided at the output of the matching unit 5. This is a circuit for use in complementing the load impedance estimation. The input impedance (40: Zlr, Zli) of the load 6 calculated from the output impedance (20) of the high-frequency power supply circuit 1 and the progress monitored by the detector 2 are used. By calculating the passing current from the wave power and comparing it with the current value detected by the current detector 7, it is possible to ensure the accuracy of the load monitor. The current detector 7 is very small and low in cost compared to the detector 4 in FIG.

Further, according to the embodiment, even when the element value of the system of the high frequency power supply device 1 is changed, it is possible to easily correct.

As mentioned above, the invention made by the present inventor has been specifically described based on the examples. However, the present invention is not limited to the above-described embodiments and examples, and needless to say, various modifications can be made. .

The present invention is suitable for a high-frequency power supply device for generating plasma or laser in a semiconductor manufacturing apparatus or a laser processing machine. This application claims the benefit of priority based on Japanese Patent Application No. 2018-042568 filed on Mar. 9, 2018, the entire disclosure of which is incorporated herein by reference.

1: High frequency power supply circuit, 1a: Arithmetic circuit, 2: Detector, 3: High frequency path, 5: Matching device, 6: Load, 7: Current detector, 10: High frequency power supply device

Claims

A high frequency power supply circuit;
A detector provided at the output of the high-frequency power supply circuit;
A high-frequency path connected to the output of the detector;
A matching unit connected to the high-frequency path and supplying high-frequency power to the input of the load,
The detector can acquire traveling wave and reflected wave information,
The high-frequency power supply circuit uses the high-frequency path and the matching unit to determine impedance information when the high-frequency path is viewed from the output of the detector calculated from the acquired traveling wave and reflected wave information. Calculate the load impedance by adding the impedance change.
High frequency power supply.
The high frequency power supply device according to claim 1,
A current detector connected to the output of the matcher;
A high-frequency power supply device that ensures the accuracy of a load monitor by comparing the current value detected by the current detector with the information on the load impedance.
The high frequency power supply device according to claim 1,
The high frequency power supply circuit includes a calculation circuit that calculates the load impedance.