JP2005158573A - Plasma generation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem where, in a plasma generation device for generating plasma using a bipolar pulse voltage, components satisfying high-withstand-voltage specifications must be used in a method using a high-voltage D.C. power source and an inverter circuit as means for generating the bipolar pulse voltage, whereby the size and the cost of the device are increased. <P>SOLUTION: Respective semiconductor switches for ON-OFF are connected to respective terminals of a charging D.C. power source, a capacitor, a boosting pulse transformer having an intermediate tap on the primary side, and a divided primary side winding, whereby two sets of closed circuits sharing the primary side winding, the semiconductor switches for ON-OFF and the capacitor are composed; currents to be carried to the two sets of closed circuits are selectively controlled by the semiconductor switches for ON-OFF to generate a bipolar pulse voltage in the secondary winding of the pulse transformer; and plasma is generated between facing electrodes connected to the secondary winding. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a plasma generation apparatus that generates plasma using a bipolar pulse voltage.

Plasma can be generated by applying a positive or negative DC bias voltage. However, this DC bias method has a weak point that a charge-up phenomenon in which only negative or positive charges are biased on the surface of the electrode occurs, plasma generation is inhibited and efficiency is very poor. After that, an attempt was made to apply a voltage in pulses, but the charge bias could not be improved. The plasma generation method disclosed in Patent Document 1 discloses a method of suppressing a charge-up phenomenon by applying a bipolar pulse so as not to bias the charge using an inverter power source having a high-voltage DC power source and a switching circuit. Yes.
Japanese Patent Laid-Open No. 11-224895 (FIG. 2)

However, the inverter power supply system having the above-described high-voltage DC power supply has a problem that the DC power supply and the switching circuit must all have a high breakdown voltage, resulting in an increase in size and cost.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a generator that does not need to increase the breakdown voltage of a DC power supply or an ON-OFF semiconductor switch, and a highly efficient and stabilized plasma. It is to provide an apparatus for generating.

  DC charging power supply, capacitor charged by the DC power supply, boosting pulse transformer having an intermediate tap on the primary side, and terminals of the primary winding divided by the intermediate tap of the boosting pulse transformer Are connected to the respective ON-OFF semiconductor switches to form two sets of closed circuits in which the primary winding of the pulse transformer, the ON-OFF semiconductor switch, and the capacitor are used in common. The current flowing through the circuit is selected and controlled by the ON / OFF semiconductor switch, a bipolar pulse voltage is generated in the secondary winding of the pulse transformer, and between the opposing electrodes connected to the secondary winding of the pulse transformer. Plasma is generated.

  The plasma-type gas processing apparatus of the present invention has an advantage that it can avoid the charge-up phenomenon by generating plasma using a bipolar pulse voltage and can generate plasma efficiently.

  The purpose of generating a bipolar pulse voltage and avoiding the charge-up phenomenon was realized by a simple method.

FIG. 1 is a connection diagram of a plasma generating apparatus in which a DC power source, a capacitor, and an ON / OFF semiconductor switch are connected to a step-up pulse transformer according to the present invention. Hereinafter, FIG. 1 will be described.

An intermediate tap 8 of a step-up pulse transformer 5 is connected to a capacitor 2 charged by a DC power source 1, and a positive polarity is obtained by switching a positive polarity ON-OFF semiconductor switch 3 connected to a primary side terminal 6. The negative polarity pulse is generated by switching the negative polarity ON-OFF semiconductor switch 4 connected to the primary side terminal 7, and the bipolar voltage boosted by the winding ratio of the boosting pulse transformer 5. A high voltage pulse is applied to the opposing electrode 9 to generate plasma.

According to this method, a low-voltage DC power supply and an inexpensive ON-OFF semiconductor switch with a low withstand voltage can be configured, and at the same time, a plasma generating apparatus that generates high-efficiency and stable plasma can be realized. Useful for.

It is a figure explaining the Example of Claim 1 of this invention. (Example 1)

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 DC power supply 2 Discharge capacitor 3 Positive-polarity ON-OFF semiconductor switch 4 Negative-polarity ON-OFF semiconductor switch 5 Boost pulse transformer 6, 7 Primary side terminal 8 Intermediate tap 9 Electrode

Claims (1)

  DC charging power supply, capacitor charged by the DC power supply, boosting pulse transformer having an intermediate tap on the primary side, and terminals of the primary winding divided by the intermediate tap of the boosting pulse transformer Are connected to the respective ON-OFF semiconductor switches to form two sets of closed circuits in which the primary winding of the pulse transformer, the ON-OFF semiconductor switch, and the capacitor are used in common. The current flowing through the circuit is selectively controlled by the ON / OFF semiconductor switch, a bipolar pulse voltage is generated in the secondary winding of the pulse transformer, and between the opposing electrodes connected to the secondary winding of the pulse transformer A plasma generating apparatus characterized by generating plasma.

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