JPH07120910B2 - Transistor type high frequency power supply - Google Patents

Description

The present invention relates to a transistor-type high-frequency power supply that combines high-frequency signals that have been separately power-amplified by a plurality of transistor amplifiers and outputs a high-frequency signal that has been significantly power-amplified. In order to remove the effect of
(Where m is an integer equal to or greater than 4) to amplify the power respectively, and the high frequency signals extracted in parallel from the m transistor amplifiers are combined by a combiner to obtain a power amplification degree m. In a transistor type high frequency power source for taking out a doubled combined high frequency signal, a combining means for combining a fixed number of signals out of the high frequency signals taken out in parallel from the m transistor amplifiers, and respective outputs of the combining means. A filter circuit for removing unnecessary frequency components from the synthesized signal and supplying the synthesized signal to the synthesizer is provided.

[Industrial application field]

The present invention relates to a transistor type high frequency power source, and more particularly to a transistor type high frequency power source that combines high frequency signals that have been separately power-amplified by a plurality of transistor amplifiers and outputs a significantly power-amplified high frequency signal.

[Conventional technology]

A transistor-type high-frequency power supply that supplies an excitation frequency (high-frequency signal) of 13.56MHz to a plasma processing device requires a large amount of power, for example, about 2400W, but there is no high-output transistor at an output of 500W or more. From
A plurality of transistor amplifiers are provided in parallel, and the output high frequency signals of the respective transistor amplifiers are combined by a combiner.

As a result, if 8 transistor amplifiers that can output high-frequency signals of 300 W are provided in parallel and the output high-frequency signals are combined by a combiner, 2400 (= 8 × 300) W
The high-frequency signal whose power has been amplified can be taken out from the combiner.

[Problems to be solved by the invention]

However, the above-mentioned conventional transistor type high frequency power supply,
Due to the high frequency generated in the transistor amplifier, it is difficult to adjust the output impedance to the prescribed 50Ω, and a heat dissipation mechanism for reducing the heat generation of the transformer is required, which causes a problem that the device becomes large.

The present invention was created in view of the above points, and an object of the present invention is to provide a transistor type high frequency power source in which the influence of unnecessary high frequency generated in the transistor amplifier is removed.

[Means for solving problems]

FIG. 1 shows the principle configuration of the present invention. In the figure, 1 is an input high frequency signal branched into m (where m is an integer of 4 or more)
Distributor, 2 ₁ to 2 _m are m transistor amplifiers, 3 ₁ to
3 _n is a synthesizing means for synthesizing a fixed number of signals at a time, 4 ₁ to 4 _n are n
The number (where n is a positive integer smaller than m) is the synthesizing means 3 ₁
Filter circuits 5 provided corresponding to 3 _n respectively, are synthesizers for synthesizing n synthesized signals and extracting synthesized high frequency signals.

The filter circuits 4 ₁ to 4 _n wave the signal band of the high frequency signal,
The frequency characteristic is set to remove unnecessary frequency components such as harmonics.

[Action]

Frequency signal taken out are respectively the power amplifier by transistor amplifier 2 ₁ to 2 _m are each a certain number of signals are respectively synthesized by the n synthesizing means 3 ₁ to 3 _n. Therefore, if the constant number is i, then n × i = m.

The high frequency signals synthesized by the synthesizing means 3 _{1 to} 3 _n and taken out in parallel are separately supplied to the filter circuits 4 ₁ to 4 _n ,
Here, the unnecessary frequency component is removed and then supplied to the synthesizer 5. As a result, the transistor amplifier from the synthesizer 5
A high-frequency signal obtained by power-amplifying each output high-frequency signal of 2 _{1 to} 2 _m by m times is extracted.

Since unnecessary high-frequency input RF signal by the filter circuit 4 ₁ to 4 _n is removed, it is possible to prevent adverse effects to the subsequent circuit due to unnecessary high frequency. Further, the number of filter circuits 4 ₁ to 4 _n can be smaller than the number of signals amplified by the transistor amplifiers 2 ₁ to 2 _m by the combining means 3 _{1 to} 3 _n , so that each signal can be filtered individually. Can reduce the amount of signal attenuation.

〔Example〕

FIG. 2 (A) is a block diagram of an embodiment of the present invention, and FIG. 2 (B) shows a change in power amplification corresponding to FIG. 2 (A). In FIG. 2A, the crystal oscillator 7 and the amplifier 8
The high-frequency signal of, for example, 13.65 MHz taken out from the oscillator 9 made up of is amplified by the preamplifier 10 to 3 W as shown in FIG. 2 (B), and then supplied to the drive amplifier 11, where it is further amplified in power. It becomes 64W.

The output high frequency signal of the drive amplifier 11 is the distributor 1
Is divided into eight by a distributor 12 corresponding to the above, and each of them is made into a high frequency signal of 8 W, and then supplied to _eight power amplifiers 13 _{1 to} 13 ₈ separately. That is, the present embodiment is a case of m = 8, and a case of n = 4 as described later.

Each of the power amplifiers 13 _{1 to} 13 ₈ outputs 8 W of the input high frequency signal to 300 W.
In a known amplifier that is composed of a plurality of transistors such that the power amplifier, said transistor amplifier 2 ₁ but constitutes a to 2 _m, to generate unwanted high frequency during its amplifying operation.

Of the power amplifiers 13 _{1 to} 13 ₈ , both output high frequency signals of 13 ₁ and 13 ₂ are supplied to the combiner 14 ₁ , and similarly both output high frequency signals of 13 ₃ and 13 ₄ are supplied to the combiner 14 ₂ and 13 _{5 respectively.} The output high frequency signals of 13 and 13 ₆ are supplied to the combiner 14 ₃ and the output high frequency signals of 13 ₇ and 13 ₈ are supplied to the combiner 14 ₄ .

The synthesizers 14 _{1 to} 14 ₄ are circuit portions which are essential parts of the present embodiment, and constitute the synthesizer means 3 _{1 to} 3 _n and the filter circuits 4 ₁ to 4 _n . In this embodiment, the combiner 14 _{1-14 4} is the structure shown in each of Figure 3.

In FIG. 3, 19 and 20 in each connector, the high frequency signal of the corresponding two power amplifiers from each 300W of the power amplifier _{131-134 8} is supplied. The first high frequency signal from the connector 19 and the second high frequency signal from the connector 20 are inductively coupled by the coils L ₁ , L ₂ and L ₃ , L ₄ and supplied to the low pass filter 21.

The low-pass filter 21 is composed of capacitors C _{1 to} C ₆ and coils L ₆ and L ₇ , and is selected as a low-pass characteristic that passes the first and second high-frequency signal frequencies of 13.65 MHz and attenuates the unnecessary high-frequency. Has been done. As a result, the unnecessary high frequency component (harmonic) is removed by the low pass filter 21 from the combined high frequency signal composed of the first and second high frequency signals.

The output synthesized high frequency signal of the low pass filter 21 is output to the connector 23 through the output transformer 22. This connector 23
Since the first and second high-frequency signals of the obtained composite high-frequency signal are 300 W each, they are amplified to 600 W which is the sum of them.

On the other hand, although not directly related to the gist of the present invention, the coils L ₂ and L ₃
And the first and second high frequency signals are combined by inductive coupling of L ₅ and then supplied to the diode D ₁ through the resistor voltage divider circuit of the resistors R ₁ and R ₂ and rectified therein.

The rectified signal extracted from the diode D ₁ is smoothed by the resistor R ₃ and the capacitor C ₇ , and then output to the connector 24 as a power monitor signal.

Referring back to FIG. 2 again, the synthesizer 14 having the above-mentioned configuration is described.
_{1-14 4} from each fetched synthesized high frequency signal, are respectively supplied to the synthesizer 15 shown in FIG. 2 (A), where they are synthesized.

As a result, as shown in FIG.
The composite high frequency signal power-amplified to 00 W (= 600 W × 4) is taken out. This composite high frequency signal is separated into an incident wave and a reflected wave by a directional coupler 16 and is subjected to power monitoring, and then applied as an plasma excitation frequency to an electrode in the process chamber via an output terminal 17. .

Although not shown in FIG. 2 (A), the power monitor signal from the directional coupler 16 is compared with the monitor signal from the connector 24, and the oscillator is adjusted so that the effective power becomes constant accordingly. The level of the oscillation frequency signal 9 is controlled.

As described above, according to this embodiment, since the high frequency is removed by the low-pass filter 21, the amount of heat generated by the output transformer 22 is small, and the output impedance can be easily adjusted. Further, reduction filter 21 is provided to a combiner 14 _{1-14 4,} the signal obtained by combining the output of the power amplifier 13 ₁ and 13 ₂ is to remove the reducing components are supplied. Therefore, the number of the reduction filters 21 is half that of the power amplifiers 13 _{1 to} 13 ₈ , and therefore the signal attenuation by the low-pass filter 21 is smaller than that in the case where a filter is provided for each power amplifier 13 _{1 to} 13 ₈ . Can be made smaller.

〔The invention's effect〕

As described above, according to the present invention, it is possible to prevent the adverse effect of the high frequency on the subsequent circuit, so that the heat generation amount of the output transformer is small, and the device for heat dissipation can be small.
Further, it has a feature that the output impedance of the transistor amplifier can be easily adjusted to a specified value. Further, the filter circuit 4 ₁ to 4 _n combined signal the signal amplified by the transistor amplifier 2 ₁ to 2 _m are supplied by synthetic means 3 ₁ to 3 _n, since it smaller than the number of signals, each signal filtering Compared with the case where it does, it has the feature that the attenuation of the signal by the filter circuit can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of the principle of the present invention, FIG. 2 is a block diagram of an embodiment of the present invention and a diagram showing a transition of power amplification, and FIG. 3 is a circuit diagram of an embodiment of a main part of the present invention. Is. In the figure, 1 and 12 are distributors, 2 ₁ to 2 _m are transistor amplifiers, 3 _{1 to} 3 _n are combining means, 4 ₁ to 4 _n are filter circuits, 5, 14 _{1 to} 14 ₄ and 15 are combiners, 13 _{1 to} 13 ₈ are power amplifiers, 21 is a low-pass filter, and L _{1 to} L ₇ are coils.

Claims (1)

[Claims] 1. A high-frequency signal is supplied in parallel through a distributor (1) to m (where m is an integer of 4 or more) transistor amplifiers (2 ₁ to 2 _m ) to amplify electric power, and the m The high-frequency signals extracted in parallel from the individual transistor amplifiers (2 ₁ to 2 _m ) are combined by the combiner (5) and the power amplification degree is m.
In the transistor-type high-frequency power source to retrieve the multiple of synthetic high frequency signal, combining means for combining each predetermined number of signals of the m transistors amplifier (2 ₁ to 2 _m) the high-frequency signal extracted in parallel from the ( 3 _{1 to} 3 _m ) and a filter circuit (4 ₁ to 4 ₁ ) for removing unnecessary frequency components from the output combined signals of the combining means (3 _{1 to} 3 _n ) and supplying them to the combiner (5). 4 _n ) and a transistor type high frequency power supply.