Method and device for detecting electric arc of plasma processing chamber

Abstract

The invention discloses a detection method and a detection device for an electric arc of a plasma processing chamber, and the method comprises the steps: transmitting radio frequency power to the interior of the plasma processing chamber through a radio frequency power source, and igniting reaction gas in the plasma processing chamber to form plasma; an output power signal and a reflection power signal of the radio frequency power source are sent to a controller, and the controller determines whether to enter a radio frequency power stable output interval or not according to the ratio of the output power signal to the reflection power signal; in the stable output interval of the radio frequency power, the average value and the maximum value of the reflection power signals are obtained through calculation of the controller; and comparing the average value of the reflection power signals with the maximum value of the reflection power signals to obtain a ratio, and judging that arc discharge occurs when the ratio is smaller than a preset threshold value. According to the invention, the purpose of rapidly detecting the micro-arc in the electric arc in the vacuum reaction cavity so as to timely know the defect state of the corresponding wafer is achieved.

Description

technical field [0001] The invention relates to the technical field of plasma processing devices, in particular to a detection method and detection device for an arc in a plasma processing chamber. Background technique [0002] Current plasma processing devices such as plasma-enhanced chemical vapor deposition (PE-CVD) systems, plasma etching systems, and sputtering systems in semiconductor production equipment are widely used throughout the production of modern electronic devices. The plasma processing device uses the working principle of the vacuum reaction chamber to process the semiconductor substrate and the substrate of the plasma flat panel. The working principle of the vacuum reaction chamber is to pass a reaction gas containing an appropriate etchant or deposition source gas into the vacuum reaction chamber, and then input radio frequency energy to the vacuum reaction chamber to activate the reaction gas to ignite and maintain the plasma body, in order to respectiv...

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Problems solved by technology

Wherein the design of the detector 40 is used to detect the stable voltage DC signal output by the high-voltage DC power supply 30, so the sampling rate is very low, and the discharge with a very short discharge time (several milliseconds) cannot be sampled and detected

Even if a higher-level detector 40 is used to sample the voltage fluctuation signal caused by the discharge, since the communication time between the PLC circuit 50 and the main controller 60 in the plasma processing device is now about 200 milliseconds, the arc discharge, especially the micro-arc discharge The time is much less than 200ms (such as a few milliseconds). For the existing common pulsed plasma processing technology (the output radio frequency power is pulsed and rapidly changed, such as 10K pulse frequency), the high-speed change of the radio frequency power itself causes the detected The voltage signal also changes at a high speed, which will cause a large number of false discharge signals to be generated

Moreover, due to the large delay, this error signal cannot correspond to the current process steps, so it is impossible to distinguish whether it is caused by the sudden change of the output power or the discharge.

There are also multiple steps with different processing parameters in other plasma treatment processes. For example, the first set of parameters is executed in step 1, and the second set of parameters is executed in step 2. During the switching process of steps 1 and 2, the existing detection system will also detect Errors to the discharge signal are actually just RF impedance mismatches caused by changes in the process environment

In the prior art, the use of electrostatic chuck (ESC) current or voltage signal to detect pulsed arc cannot capture reflected power data at such a high speed, and it cannot meet the needs of pulsed plasma processing technology, so the arc cannot be detected in time. Micro-arc, and because there is a voltage divider circuit in the ESC power supply, the DC signals generated by many micro-arcs will be submerged by noise, and the micro-arc cannot be detected

Therefore, it is impossible to know whether the discharge signal at this time is a peak mismatch or a change caused by the original RF power source itself.

And the presence of micro-arc will cause the pollutants from the side wall of the vacuum reaction chamber to accumulate on the wafer 10 being processed in the vacuum reaction chamber, thereby causing a defective wafer 10, which will affect the subsequent process. progress

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