Test apparatus and plasma processing apparatus

Patent metadata

Field	Value
Publication number	US-9673027-B2
Application number	US-201414161538-A
Country	US
Kind code	B2
Filing date	Jan 22, 2014
Priority date	Jan 24, 2013
Publication date	Jun 6, 2017
Grant date	Jun 6, 2017

Abstract

A test apparatus for efficiently and accurately testing a high frequency voltage dependency of an impedance of a test object without damaging the test object. The test apparatus includes a high frequency power source unit, a reference waveform generator, a matching device, an oscilloscope, a control panel, and a main control unit. The test apparatus may boost a high frequency pulse output at a relatively low power from the high frequency power source unit to a voltage required for a high frequency withstand voltage test to be applied to a test object in a state where impedance matching is performed between the high frequency power source unit and the test by the matching device, that is, under a tuned state. Whether the waveform of the voltage applied to the test object is a defined waveform may be concisely monitored and observed by the oscilloscope.

First claim

What is claimed is:

1. A test apparatus of testing a high frequency voltage dependency of an impedance on a test object having a capacitive or inductive impedance, the test apparatus comprising:
a high frequency power source unit configured to output a high frequency wave having a predetermined frequency in a variable envelope;
a control unit configured to control the high frequency power source unit so as to output a high frequency pulse having an envelope portion increasing in a reversed taper shape in a predetermined section on a time axis;
a matching unit configured to establish an impedance matching between the high frequency power source unit and the test object; and
a monitor unit configured to monitor an envelope waveform of a high frequency voltage output from the matching unit and applied to the test object for a pulse duration of the high frequency pulse according to the high frequency pulse output from the high frequency power source unit; and
wherein the monitor unit is further configured to determine whether the test object withstands the high frequency voltage applied thereto without causing an insulation failure or a dielectric breakdown in response to a determination that the envelope waveform of the high frequency voltage applied to the test object is maintained in a same envelope waveform as the high frequency pulse output from the high frequency power source unit and has a rhomboid waveform on the time axis.

2. The test apparatus of claim 1 , wherein the monitor unit includes an oscilloscope.

3. The test apparatus of claim 1 , wherein the monitor unit includes:
a voltage sensor configured to detect an envelope of the high frequency voltage applied to the test object so as to generate an envelope detection signal representing the envelope of the high frequency voltage, and
a display unit configured to display the envelope waveform of the high frequency voltage based on the envelope detection signal.

4. The test apparatus of claim 1 , wherein the monitor unit includes:
a voltage sensor configured to detect an envelope of the high frequency voltage applied to the test object so as to generate an envelope detection signal representing the envelope of the high frequency voltage, and
a signal processing unit configured to perform a signal processing to determine whether a slope of the envelope of the high frequency voltage is bent when the envelope increases in the reversed taper shape in the predetermined section on the time axis, based on the envelope detection signal.

5. The test apparatus of claim 4 , wherein when it is determined that the slope of the envelope of the high frequency voltage is bent, the signal processing unit determines a voltage value of the bent point as a high frequency withstand voltage of the test object.

6. The test apparatus of claim 1 , wherein the control unit includes a reference waveform generator configured to generate a reference waveform signal that defines an envelope waveform of the high frequency pulse, and
the high frequency power source unit includes a high frequency oscillator configured to oscillate and output the high frequency wave at a predetermined power, a high frequency power amplifier configured to amplify the high frequency wave output from the high frequency oscillator to a desired power, and a power source control unit configured to variably control a gain of the high frequency power amplifier according to the reference waveform signal generated from the reference waveform generator.

7. The test apparatus of claim 6 , wherein the high frequency power source unit includes a directional coupler that is provided on a high frequency transmission line between the high frequency power amplifier and the matching unit to output a progressive wave detection signal representing a voltage of a progressive wave propagating on the high frequency transmission line in a forward direction, and
the power source control unit compares the progressive wave detection signal output from the directional coupler to the reference waveform signal and variably controls the gain of the high frequency power amplifier such that a comparison error is close to zero.

8. The test apparatus of claim 6 , wherein the high frequency power source unit includes a directional coupler that is provided on a high frequency transmission line between the high frequency power amplifier and the matching unit to output a reflected wave detection signal representing a voltage or a power of a reflected wave propagating on the high frequency transmission line in a reverse direction, and
the power source control unit stops amplification of the high frequency power amplifier immediately when the voltage or the power of the reflected wave exceeds a predetermined threshold value based on the reflected wave detection signal output from the directional coupler.

9. The test apparatus of claim 1 , wherein the high frequency pulse output from the high frequency power source unit has a triangular envelope waveform.

10. The test apparatus of claim 1 , wherein the high frequency pulse output from the high frequency power source unit has a rhomboid envelope waveform.

11. A test apparatus of testing a high frequency voltage dependency of an impedance on a test object having a capacitive or inductive impedance, the test apparatus comprising:
a high frequency power source unit configured to output a high frequency wave having a predetermined frequency;
a matching unit configured to establish impedance matching between the high frequency power source unit and the test object;
a control unit configured to control the high frequency power source unit so as to intermittently output a plurality of high frequency pulses each having an amplitude increasing with elapse of time on a time axis;
a voltage measuring unit configured to measure a high frequency voltage output from the matching unit and applied to the test object according to each of the plurality of high frequency pulses;
a current measuring unit configured to measure a high frequency current output from the matching unit and flowing in the test object according to each of the plurality of high frequency pulses;
an impedance calculating unit configured to calculate an impedance measurement value of the test object based on a voltage measurement value and a current measurement value which are obtained from the voltage measuring unit and the current measuring unit, respectively; and
a monitoring unit configured to determine whether an impedance of the test object at a present time has substantially the same value as an impedance of the test object at the high frequency pulse applied at a previous time such that the monitoring unit determines the high frequency voltage dependency of the impedance based on the voltage measurement value obtained from the voltage measuring unit and the impedance measurement value obtained from the impedance calculating unit, and wherein the high frequency voltage is applied to the test object for a pulse duration of the high frequency pulse.

12. The test apparatus of claim 11 , wherein, when the impedance measurement value at an n th (n is an integer of 2 or more) high frequency pulse is smaller than the impedance measurement value at an (n−1) th high frequency pulse by a predetermined value or more, the monitoring unit determines a high frequency withstand voltage of the test object based on at least one of the voltage measurement value at the (n−1) th high frequency pulse and the voltage measurement value at the n th high frequency pulse.

13. The test apparatus of claim 11 , wherein, when the impedance measurement value at an n th (n is an integer of 2 or mor

Assignees

• Tokyo Electron Ltd

Inventors

• Yamamoto Takashi
• Shimada Junichi

Classifications

• H10P74/238

  comprising acting in response to an ongoing measurement without interruption of processing, e.g. endpoint detection or in-situ thickness measurement · CPC title

• H10P74/207

  Electrical properties, e.g. testing or measuring of resistance, deep levels or capacitance-voltage characteristics · CPC title

• H01J37/32174

  Circuits specially adapted for controlling the RF discharge · CPC title

• H01J37/32082

  Radio frequency generated discharge (H01J37/32357, H01J37/32366, H01J37/32394 and H01J37/32403 take precedence) · CPC title

• H01J37/32917 Primary

  Plasma diagnostics · CPC title