JPH03291006A - High frequency power unit in plasma equipment - Google Patents

Abstract

PURPOSE:To operate a final stage amplifier with a small loss and to improve the reliability by operating the final stage amplifier at the saturation region independently of the quantity of output power. CONSTITUTION:A high frequency oscillating signal whose frequency is, e.g. 13.56MHz is used for the oscillating signal from a crystal oscillator 3 and a transformer is used for a 1st stage amplifier 5 and a final stage amplifier 7 respectively. The final stage amplifier 7 is normally operated at a saturation region. Moreover, the efficiency is constant independently of a DC power supply voltage and the output power and the loss are both in proportion to the DC power supply voltage. Thus, the output power is limited by supply power of the final stage amplifier 7. Thus, the final stage amplifier 7 is operated at the saturation region independently of the quantity of the output power at a small loss and the reliability is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a high frequency power supply device for a plasma device using a high frequency glow discharge phenomenon.

(Prior Art) Conventionally, a high-frequency power supply device in a plasma device using a high-frequency glow discharge phenomenon has a crystal oscillator 10 using a crystal oscillator, as understood from the block diagram shown in FIG.
1 is activated, a weak high-frequency signal is oscillated from the crystal oscillator 101, taken into the first amplifier 103, and amplified. The amplified signal amplified by this first amplifier 103 is taken into a variable attenuator 105.

This variable attenuator 105 changes the amount of attenuation without amplifying the power much, and based on this amount of attenuation, the second amplifier 10
7. The output power is outputted through a final stage amplifier 109 with variable output power. It is widely known that the output power, efficiency, and loss variably output from the final stage amplifier 109 have a relationship as shown in FIG. 5 with respect to the input power for boat fishing. .

(Problem to be solved by the invention) By the way, the output power with respect to the input power shown in FIG.
As can be seen from the relationship between efficiency and loss, as the input power increases, the output power and efficiency increase monotonically. Above this, the output power, efficiency, and loss are each saturated.

As a result, since there is no change in the output power above point A (saturation point), the usable range for the input power is between 0 and A in order to output the output power variably. however,
In this range (0-A), there is a maximum value (point B) of the power loss at the final stage, which is much larger than the power loss at the saturation point (A). Therefore, the final stage amplifier 109
The transistor must be selected to satisfy the maximum loss (point B), and the heat dissipation design is also similar, so it was difficult to select an effective output power.

An object of the present invention is to provide a high-frequency power supply device for a plasma device in which the final stage amplifier operates in the saturation region to output power with small loss and improve reliability in order to improve the above-mentioned problems. There is a particular thing.

[Structure of the Invention] (Means for Solving the Problem) In order to achieve the above object, the present invention provides a high frequency power supply device for a plasma device using a high frequency glow discharge phenomenon, which amplifies a high frequency signal oscillated from an oscillator. a final stage amplifier that further amplifies the amplified signal amplified by the first amplifier and outputs it as output power, and a variable DC power supply that variably applies a voltage to the final stage amplifier. A high frequency power supply device for a plasma device was constructed.

(Function) By employing the high frequency power supply device in the plasma apparatus of the present invention, the output power output from the final stage amplifier is limited by the voltage of the variable DC power supply connected to the final stage amplifier. Therefore, the final stage amplifier operates in the saturation region regardless of the magnitude of the output power, operates with small loss, and improves reliability.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

Referring to FIG. 1, a high frequency power supply device 1 in a plasma device includes a crystal oscillator 3. Amplifier 5. It is composed of a final stage amplifier 7 and a variable DC power supply 9. That is, the first amplifier 5 is connected to the crystal oscillator 3, and when the crystal oscillator 3 is activated, a weak high frequency signal is oscillated and the first amplifier 5 is connected to the crystal oscillator 3.
The signal is taken into amplifier 5.

The signal is amplified by the first amplifier 5, and further amplified by the final stage amplifier 7 connected to the first amplifier 5.

Since a variable DC power supply 9 is connected to the final stage amplifier 7, input power is variably inputted from the variable DC power supply 9 to the final stage amplifier 7, and output power is output from the final stage amplifier 7. Ru.

A concrete high frequency power supply device 1 based on the block diagram shown in Fig. m1 is shown in Fig. 2. In FIG. 2, parts that are the same as those shown in FIG. 1 are designated by the same reference numerals and will be described.

In FIG. 2, the crystal oscillator 3 is, for example, 13.56
Using a high frequency wave consisting of MH2, the first amplifier 5. A transformer is used as the final stage amplifier 7, respectively. Furthermore, the circuit includes two transistors connected between the first amplifier 5 and the final stage amplifier 7.

As mentioned above, when a voltage is variably inputted from the variable DC power supply 9 to the final stage amplifier 7, the relationship as shown in FIG. 3 is obtained. That is, as can be seen from FIG. 3, the final stage amplifier 7
is always used in the saturated region above the conventional A point. Moreover,
Efficiency is constant regardless of DC power supply voltage, and output power and loss are both proportional to DC power supply voltage.

Therefore, the output power is limited by the power supplied by the final amplifier 7. If the circuit constants are constant, the supplied power is uniquely determined by the voltage of the supplied power source, so the output power can be increased or decreased by varying the voltage of the variable DC power source 9. .

Therefore, the final stage amplifier 7 operates in the saturation region regardless of the magnitude of the output power, and operates with small loss, thereby improving reliability.

Note that this invention is not limited to the embodiments described above, and can be implemented in other forms by making appropriate changes.

[Effects of the Invention] As understood from the above description of the embodiments, according to the present invention, the output power output from the final stage amplifier is limited by the voltage of the variable DC power supply connected to the final stage amplifier. Ru. Therefore, the final stage amplifier operates in the saturation region regardless of the magnitude of the output power, and operates with small loss, thereby improving reliability.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a high frequency power supply device in a plasma device of the present invention, Fig. 2 is a specific electric circuit diagram based on the block diagram of Fig. 1, and Fig. 3 is a DC power supply voltage obtained by the present invention. Figure 4 is a block diagram of a high-frequency power supply device in a conventional plasma device. Figure 5 is a diagram showing the relationship between input power, output power, efficiency, and loss obtained by the conventional method. It is a relationship diagram. 1...High frequency power supply W 3...Crystal oscillator 5...
・First amplifier 7... Final stage amplifier 9... Variable DC power supply

Claims (1)

[Claims] A high frequency power supply device for a plasma device using a high frequency glow discharge phenomenon, which includes a first amplifier that amplifies a high frequency signal oscillated from an oscillator, and further amplifies the amplified signal amplified by the first amplifier and outputs it as output power. 1. A high-frequency power supply device for a plasma apparatus, comprising a final stage amplifier and a variable DC power supply that variably applies voltage to the final stage amplifier.