JPH056799A - Rf power supply device for icp - Google Patents

Abstract

PURPOSE:To simplify constitution by providing a work coil grounded in its center tap on the output side of a matching device to sum power in the work coil. CONSTITUTION:A RF signal transmitted from an oscillator 1 is amplified by a preamplifier, then divided into two by a power divider 3, and transmitted to first and second power amplifiers 4a, 4b with the phases being shifted by 180 deg.. The RF power amplified by the power amplifiers 4a, 4b is transmitted through transmission lines 5a, 5b, subjected to impedance conversion by a matching device 6, and then sent to a work coil 7. The work coil 7 is grounded in its center so that a power is summed in this coil 7 when a waveform of reversed phase is sent from both ends of the work coil 7. Thus, the power sum and impedance conversion in the course are not required, and the constitution is simplified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency inductively coupled plasma (hereinafter referred to as "ICP") RF power supply device,
More specifically, the present invention relates to an ICP RF power supply device that can be attached to an ICP analysis device and combine power with a simple configuration.

[0002]

2. Description of the Related Art A high-frequency inductively coupled plasma analyzer using a quadrupole mass spectrometer generally supplies argon gas from an argon gas supply source to the outer chamber and outermost chamber of a plasma torch via a gas regulator. The sample (analysis target) is supplied to the inner chamber from the sample introduction device. Also,
A high-frequency current is applied to the high-frequency induction coil wound around the plasma torch by a high-frequency power source, and a high-frequency magnetic field is formed around the coil. In this state, when electrons or ions are implanted in the argon gas in the vicinity of the high frequency magnetic field, high frequency inductively coupled plasma is instantaneously generated by the action of the high frequency magnetic field.

Further, the inside of the fore chamber main body sandwiched between the nozzle and the skimmer is sucked by a vacuum pump. Further, the center chamber is provided with an extraction electrode, an aperture lens, a quadrupole lens, an aperture, and an entrance lens, and the inside of the center chamber is a first oil diffusion pump. Rear chamber, which is aspirated by and contains a quadrupole mass filter
The inside is sucked by the second oil diffusion pump.

In this state, the sample vaporized as described above is introduced into the high frequency inductively coupled plasma, and ionization and light emission are performed. Ions in the plasma are converged through the extraction electrode and the ion lens system after passing through a nozzle and a skimmer, and are introduced into the quadrupole mass filter.

Of the ions thus entered into the quadrupole mass filter, only the ions having the desired mass-to-charge ratio pass through the quadrupole mass filter and are guided to the secondary electron multiplier to be detected. This detection signal is sent to the signal processing unit for calculation /
By processing, the elemental analysis value of the measured element in the sample can be obtained. Also, the ICP power source is 27.12 MHz or 40.68 MHz and 1.6 to
It is common to output 2.0 kW.

[0006]

However, in the above-mentioned conventional example, in the case of the vacuum tube, this output can be obtained by one vacuum tube, but in the case of the semiconductor amplifier, the above output can be obtained by a single module. Was difficult. Therefore, the outputs of a plurality of modules are combined to obtain the above output, and there is a drawback that the division and combination of power are required and the configuration becomes complicated.

The present invention has been made in view of the above situation, and its problem is a highly reliable IC having a simple circuit structure and no limitation of heat generation due to the core of the synthesis section.
An object is to provide an RF power supply device for P.

[0008]

The present invention is an R for ICP.
In the F power supply device, an oscillator, a preamplifier that amplifies an RF signal from the oscillator, a power divider that receives the output of the preamplifier, divides the output into two, and outputs the output with a phase shift of 180 °, and first and second A power amplifier, a matching device that performs impedance conversion of the electric power transmitted through the transmission line, and a work coil whose center tap is grounded are provided.
The above problem is solved by combining electric power with the work coil.

[0009]

The present invention operates as follows. That is, the RF signal sent from the oscillator is amplified by the preamplifier,
It is divided into two by the power divider, and the phase is shifted by 180 ° and sent to the first and second power amplifiers. The RF power whose amplitude has been increased by these power amplifiers is sent to a matching device via a transmission line, impedance-converted by the matching device, and sent to a work coil. This work coil is the center
Is grounded, and when waveforms of opposite phases come from both ends of the work coil, power is combined in the coil.

[0010]

The present invention will be described in detail below with reference to the drawings. FIG. 1 is a block circuit diagram of an embodiment of the present invention, in which 1 is an oscillator for oscillating and generating an RF (high frequency) source, for example an oscillator made of crystal, and 2 is a power sufficient to drive a power amplifier described later. The preamplifier 3 that amplifies the transmission output up to and receives the output of the preamplifier 2 and divides it into two and sets the phase to 180
The power dividers 4a and 4b, which are shifted and output, are power amplifiers for amplifying power enough to generate ICP, 6
Is a matching unit that performs impedance conversion for transmitting the electric power transmitted through the transmission lines 5a and 5b to a work coil described later, 61 and 62 are parallel capacitors, 63 and 64 are series capacitors, and 7 is a center. It is a work coil whose tap is grounded.

In the embodiment of the present invention comprising such a block circuit, for example, 27.
The RF signal of 12 MHz or 40.68 MHz is amplified by the preamplifier 2, then divided into two by the power divider 3, the phases are shifted by 180 °, and the signals are sent to the first and second power amplifiers 4a and 4b, respectively. .

The RF power whose amplitude has been increased by the power amplifiers 4a and 4b is sent to the matching unit 6 via the transmission lines 5a and 5b, and is impedance-converted by the matching unit 6 to be converted into a work coil. Sent to 7. The center of the work coil 7 is grounded, and when waveforms of opposite phases come from both ends of the work coil 7, electric power is combined by the coil. The present invention is not limited to the above-mentioned embodiment, and various modifications can be made.

[0013]

According to the present invention as described in detail above, in the RF power supply device for ICP, the oscillator, the preamplifier for amplifying the RF signal from the oscillator, the output of the preamplifier, and the division into two phases are provided. A power divider that shifts the output by 180 °, first and second power amplifiers, a matching device that performs impedance conversion of the power sent through the transmission line, and a center-tapped power supply. The coil coil is provided, and power is combined by the work coil.

Since the electric power is combined by the work coil in this way, there is an advantage that the composition and the impedance conversion are not required on the way and the structure is simpler than the conventional example.
Further, in the above-mentioned conventional example, use of a magnetic material is indispensable for power synthesis and impedance conversion, and heat generation becomes large at 2 kW and reliability becomes a problem. However, according to the present invention, such a magnetic material is used. Since there is no need to use, there is also an advantage that reliability is improved. Therefore, according to the present invention, it is possible to realize a highly reliable ICP RF power supply device which has a simple circuit configuration and is free from the limitation of heat generation due to the core of the combining unit.

[Brief description of drawings]

FIG. 1 is a block circuit diagram of an essential part of an embodiment of the present invention.

[Explanation of symbols]

 1 Oscillator 2 Preamplifier 3 Power divider 4a, 4b Power amplifier 5a, 5b Transmission line 6 Matching device 61,62 Parallel capacitor 63,64 Series capacitor 7 Work coil

Claims (1)

Claim: What is claimed is: 1. An ICP RF power supply device comprising: an oscillator; and a preamplifier for amplifying an RF signal from the oscillator.
It receives the output of the preamplifier and divides it into two and sets the phase to 180
A power divider that shifts the output, a first and a second power amplifier, a matching device that performs impedance conversion of the power sent through the transmission line, and a work coil whose center tap is grounded. And an RF power supply device for ICP, characterized in that electric power is combined by the work coil.