Daihen Corporation

Yuji Yoshizako

Michio Taniguchi

Toyokazu Kitano

Yuji Ishida

Yoshinobu Kasai

Akie Nakamoto

Tsuneo Ito

A phase difference detector detects the phase difference between two AC signals at a high speed and with high accuracy. A phase difference computation unit computes the phase difference &#x3c6;(=&#x3c6;&#x2212;&#x3c6;) between two detected voltages v(phase angle: &#x3c6;) and v(phase angle: &#x3c6;). The phase difference computation unit uses a sine wave vand a cosine wave vgenerated separately and having the same frequency as the fundamental frequency of the voltages vand v, to perform computation of v=v&#xd7;v, v=v&#xd7;v, v=v&#xd7;v, v=v&#xd7;v, and then extracts DC components I=(&#x2212;A/2)&#xb7;sin(&#x3c6;), R=(A/2)&#xb7;cos(&#x3c6;), I=(&#x2212;A/2)&#xb7;sin(&#x3c6;), R=(A/2)&#xb7;cos(&#x3c6;) at low-pass filters. The phase difference computation unit computes R=R&#xd7;R+I&#xd7;Iat a complex multiplying unit to obtain R=(A&#xb7;A/4)&#xb7;cos(&#x3c6;), computes I=R&#xd7;I&#x2212;R&#xd7;Ito obtain I=(A&#xb7;A/4)&#xb7;sin(&#x3c6;), and computes &#x3c6;=tan(I/R) at the arctangent calculation unit, thereby obtaining the phase difference &#x3c6;.

Phase difference detector, phase difference detection program, and plasma processing system using the phase difference detector

A phase adjusting circuit for adjusting phases of output powers from two high frequency power generators in a plasma processing apparatus comprises first and second synthesizing circuits for generating first and second high frequency signals of a predetermined waveform with frequencies of f0 and f0.+-..DELTA.f (.DELTA.f&lt;&lt;f0), a phase difference detection circuit for detecting a phase difference between detection signals of plate electrodes, a third waveform synthesizing circuit for generating a high frequency signal with frequency and waveform same as the first frequency signal which has a phase determined from a phase error between a set phase difference and an output from the phase difference detection circuit and a phase adjusting circuit which determines output powers of the two high frequency power generators base on outputs of the first and third waveform synthesizing circuits.

Automatic phase adjusting circuit for a plasma processing apparatus

In a microwave power source apparatus for a microwave oscillator for generating a microwave, a DC power source supplies a DC power for generating the microwave to the microwave oscillator. A measuring section of a voltage standing wave detector is mounted on a microwave transmission line connected between the microwave oscillator and a microwave load, and measures either one of an impedance seen looking toward the microwave load at a mounted point thereof and a reflection coefficient thereat by detecting a voltage standing wave of the microwave being generated by the microwave oscillator and propagating on the microwave transmission line. A controller calculates a progressive wave power of the microwave propagating on the microwave transmission line from the microwave oscillator toward the microwave load based on either one of the impedance and the reflection coefficient measured by the measuring section, and controls the DC power source to adjust the progressive wave power of the microwave to a predetermined desirable adjustment value based on the calculated progressive wave power.

Growing community of inventors

Osaka, Japan

Yuji Yoshizako