JPH0693437A - High-frequency device - Google Patents

Abstract

PURPOSE:To provide the high-frequency device which can attain matching in a short period of time without loss time. CONSTITUTION:An impedance detector 15 for detecting impedance and a phase detector 16 for detecting the phase difference between the voltage and current of a high frequency are separately provided. A floating inductance component 17 is provided between this impedance detector 15 and the phase detector 16. A wiring, such as coil or copper strip formed long, is used as this floating impedance component 17. The impedance detected by the impedance detector 15 is compared with a reference voltage in a comparing amplifier 8 and the differential signal thereof is supplied to a motor 9 for regulating a matching variable capacitor 4. The phase difference detected by the phase detector 16 is compared with a reference voltage in a comparing amplifier 10 and the differential signal thereof is supplied to a motor 11 for regulating a tuning variable capacitor 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency device such as a high frequency sputtering device or an etching device which can perform impedance matching in a short time.

[0002]

2. Description of the Related Art In a high frequency sputtering apparatus, a high frequency is applied between two electrodes to sputter one electrode (sample) to clean the surface of the sample. In another high-frequency device, a high frequency is applied between two electrodes so that particles sputtered from one electrode are attached to a substrate arranged close to the electrode. FIG. 1 shows an outline of such a high frequency device,
1 is a high frequency oscillator. The high frequency from the high frequency oscillator 1 is supplied to the matching box 3 via the detector 2. The matching box 3 includes a matching variable capacitor 4, a tuning variable capacitor 5, and a coil 6. The high frequency from the matching box 3 is supplied to the load 7. The detector 2 detects the high-frequency voltage and current input to the matching box 3, and the phase difference θ between the voltage and the current.

In such a configuration, the impedance and the phase are obtained based on the voltage, current and phase detected by the detector 2, and the capacitance of the matching variable capacitor 4 in the matching box 3 is changed based on the impedance value. , The capacitance of the tuning variable capacitor 5 is changed based on the phase difference. That is, the impedance Z detected by the detector 2 is supplied to the comparison amplifier 8 and compared with the reference voltage. The output of the comparison amplifier 8 is supplied to the motor 9 that drives the matching variable capacitor 4. As a result, the matching variable capacitor 4 is adjusted by the motor 9 so that the value of the impedance Z becomes equal to the reference voltage. Further, the phase difference θ detected by the detector 2 is supplied to the comparison amplifier 10 and compared with the reference voltage. The output of the comparison amplifier 10 is supplied to the motor 11 that drives the tuning variable capacitor 5. As a result, the matching variable capacitor 5 is adjusted by the motor 11 so that the value of the phase difference θ becomes equal to the reference voltage (0).

[0004]

FIG. 2 shows a locus of the input impedance to the matching box 3 according to the Smith chart, in which the tuning variable capacitor 5 is fixed and the matching variable capacitor 4 is variable. The impedance | Z | obtained by the detector 2 is the matching point impedance (50
The capacitance of the matching variable capacitor 4 can be changed according to whether it is larger or smaller. Detection impedance ｜ Z
When | is larger than 50Ω, the capacitor 4 is driven in the direction of increasing capacity. If the detected impedance | Z | is smaller than 50Ω, the capacitor 4 is driven in the direction of decreasing its capacity. In such a drive system, the region shown by the dotted line in the circular impedance locus I _{Z in} the figure has the capacitor 4 conversely increasing in capacity in spite of the impedance Z being smaller than 50Ω. The capacitor 4 is driven in such a direction that the capacitor 4 is driven and the capacity is reduced after the capacity is maximized. Therefore, loss time will occur before matching is performed.

FIG. 3 shows the locus of the input impedance to the matching box 3 by the Smith chart,
The tuning variable capacitor 5 is variable, and the matching variable capacitor 4 is fixed. The capacitance of the tuning variable capacitor 5 is changed according to the phase θ detected by the detector 2. In this case, when the phase θ is positive, the capacitance of the tuning variable capacitor 5 is driven in an increasing direction, and when the phase θ is negative, the capacitor 5 is driven.
It is driven in the direction of decreasing the capacity of. In such a driving method, of the circular impedance locus Iθ in the figure,
In the region shown by the dotted line, although the phase θ is positive, the capacitor 5 is driven in the opposite direction in which the capacitance decreases, and the capacitor 5 increases in the direction in which the capacitance is minimized.
Is driven. Therefore, loss time will occur before matching is performed.

By the way, the locus of the input impedance in FIG. 2 is inclined at the center because of the stray inductance δ between the detector 2 and the matching box 3 in FIG. 1, and therefore is shown by the dotted line. A reverse rotation region of the variable capacitor occurs. From this, it is conceivable to further increase the stray inductance δ and shift the center of the impedance locus I _Z by 90 ° as shown in FIG. 4 to eliminate the reverse rotation region of the variable capacitor.

However, when the stray inductance δ is increased, as shown in FIG. 5, the center of the locus Iθ of the input impedance is further displaced, and the reverse rotation region shown by the dotted line is further expanded. Therefore, even if the stray inductance is increased, the matching variable capacitor 4
However, the adjustment of the tuning variable capacitor 5 requires more time, and as a result, the matching time cannot be shortened.

The present invention has been made in view of the above points, and an object thereof is to realize a high frequency device capable of performing matching in a short time with less loss time.

[0009]

A high frequency device according to the present invention is arranged between a high frequency power source, a load to which high frequency power is supplied from the high frequency power source, a power source and the load, and a matching variable capacitor and a tuning variable capacitor. A matching box composed of a capacitor and a coil, an impedance detector provided between the power supply and the matching box to detect the input impedance, and an input high frequency voltage and current provided between the impedance detector and the matching box. It has a detector that detects the phase of and, and an inductance component that is placed between the impedance detector and the phase detector, and adjusts the capacitance of the matching variable capacitor according to the impedance detected by the impedance detector. Variable tuning depending on the phase detected by the detector It is characterized by being configured to adjust the capacity of the capacitor.

[0010]

In the high frequency device according to the present invention, an impedance detector and a phase detector are separately provided, and a floating inductance component is inserted between the impedance detector and the phase detector to detect the impedance by the impedance detector. The capacitance of the matching variable capacitor is adjusted according to the impedance obtained, and the capacitance of the tuning variable capacitor is adjusted according to the phase detected by the phase detector.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 6 shows an embodiment of the present invention, in which the same reference numerals as those in the conventional apparatus of FIG. In this embodiment, between the high frequency oscillator 1 and the matching box 3, an impedance detector 15 for detecting the high frequency impedance | Z |
And a phase detector 16 for detecting the phase difference θ between the high frequency voltage and the current.

A floating inductance component 17 is provided between the impedance detector 8 and the phase detector 9. As the stray inductance component 17,
Wiring such as coils and elongated copper strips are used. The impedance detected by the impedance detector 15 is compared with the reference voltage by the comparison amplifier 8, the difference signal is supplied to the motor 9 that adjusts the matching variable capacitor 4, and the phase difference detected by the phase detector 16 is detected. Is compared with a reference voltage by a comparison amplifier 10, and the difference signal is supplied to a motor 11 that adjusts the tuning variable capacitor 5. The operation of such a configuration will be described below.

With the above-described structure, the high frequency power from the high frequency oscillator 1 is applied to the load 7. At this time, the high frequency oscillator 1 and the load side impedance are matched to efficiently supply the high frequency to the load 7. , Matching box 3
The matching variable capacitor 4 and the tuning variable capacitor 5 therein are adjusted to perform impedance matching. The operation of impedance matching in this embodiment will be described below.

First, the high frequency input impedance │Z│ to the matching box 3 detected by the impedance detector 15 is compared with the reference voltage by the comparison amplifier 8, and the difference signal is compared with the matching variable capacitor 4 in the matching box 3. Is supplied to the motor 9 for adjusting The motor 9 adjusts the capacitor 4 so that the impedance value becomes a predetermined value (for example, 50 ohm). The stray inductance between the detector 15 and the matching box 3 at this time is the sum of the stray inductance δ ₂ due to the inductance component 17 and the stray inductance δ ₁ between the phase detector 16 and the matching box 3. , Its value has been increased. As a result, the impedance locus I _Z has a center of 9 as shown in FIG.
It is rotated by 0 ° so that there is no reverse rotation area. Therefore,
The matching variable capacitor 4 can be adjusted in a short time.

On the other hand, the phase difference θ detected by the phase detector 16 is compared with the reference voltage by the comparison amplifier 10, and the difference signal adjusts the tuning variable capacitor 5.
1 is supplied. The motor 11 adjusts the capacitor 5 so that the value of the phase difference θ becomes zero. Detector 1 at this time
Stray inductance between 6 and matching box 3 is [delta] _1, by very small this [delta] _1, the impedance locus Iθ is as shown in FIG. Therefore, the reverse rotation region has a very narrow range as shown by the dotted line, and the tuning variable capacitor can be adjusted in a relatively short time.

[0016]

As described above, in the high frequency device according to the present invention, the impedance detector and the phase detector are separately provided, and the floating inductance component is provided between the impedance detector and the phase detector. Inserted, the capacitance of the matching variable capacitor is adjusted according to the impedance detected by the impedance detector, and the capacitance of the tuning variable capacitor is adjusted according to the phase detected by the phase detector, so there is no loss time. Matching can be done in a short time.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a conventional high frequency device.

FIG. 2 is a diagram showing a locus of impedance.

FIG. 3 is a diagram showing a locus of impedance.

FIG. 4 is a diagram showing a locus of impedance.

FIG. 5 is a diagram showing a locus of impedance.

FIG. 6 is a diagram showing an embodiment of the present invention.

[Explanation of symbols]

 1 High Frequency Oscillator 3 Matching Box 4 Matching Variable Capacitor 5 Tuning Variable Capacitor 7 Load 8,10 Comparative Amplifier 9,11 Motor 15 Impedance Detector 16 Phase Detector 17 Stray Inductance Component

Claims (1)

[Claims] 1. A high-frequency power supply, a load to which high-frequency power is supplied from the high-frequency power supply, a matching box that is disposed between the power supply and the load, and includes a matching variable capacitor, a tuning variable capacitor, and a coil, and a power supply. An impedance detector provided between the matching box and the impedance detector for detecting the input impedance, a detector provided between the impedance detector and the matching box for detecting the phase of the input high frequency voltage and current, and impedance detection It has an inductance component placed between the phase detector and the phase detector, adjusts the capacitance of the matching variable capacitor according to the impedance detected by the impedance detector, and changes the tuning according to the phase detected by the phase detector. A high frequency configured to adjust the capacitance of the capacitor Wave device.