The Octiv Mono is a precision plasma RF Power Meter used widely in laboratories and industry. The Octiv Mono operates to 1% true accuracy, is NIST traceable and is immune to harmonics, making it the most trusted plasma RF Power Meter for applications such as semiconductor manufacturing.
It takes the confusion out of choosing a plasma RF Power Meter and reduces your cost by providing a single sensor solution covering the full power and frequency range needed for most applications. The Octiv Mono provides a choice of five standard frequency ranges.
The Octiv Mono plasma RF Power Meter helps solve issues such as poor production yields, tool matching, fault detection and classification. It helps to define exact process windows and determines the health of power sub-systems. It also helps to determine process run to run stability and gives the user the confidence to trust the accuracy of the most complex process input, plasma RF power delivery.
THEORY OF OPERATION
The Octiv Mono is a precision plasma RF Power Meter with the ability to operate up to powers of 12kW and as low as 250mW. It incorporates a broadband design ranging from 350kHz to 60MHz, which means a single unit can be configured to monitor most RF power systems found in today's plasma research Labs.
The sensor incorporates a 50 Ohm transmission line with embedded voltage and current pick-ups, analogue signal conditioning, a digitizer, digital signal processing and USB communications.
The sensor is inserted into a transmission line between the generator and load, typical RF power transmission lines are 50 Ohms and the sensor is designed with a 50 Ohm characteristic impedance so no reflections are case by inserting the sensor on the line.
RF Pick-ups
The Octiv uses two passive pick-ups to detect the RF voltage and current. The current pick-up consists of a conductive loop positioned between the inner conductor and the outer conductor of the co-axial transmission line. The conductive loop is aligned perpendicular to the magnetic flux. It produces a signal proportion to the strength of the magnetic field cutting the loop, which in turn is proportional to the RF current.
The voltage pick-up consists of a conducting plate position between the inner and outer conductors of the transmission line. This construction forms two capacitors, one between the plate and transmission line's inner conductor, and the other between the plate and the transmission line's shield or return path. The two capacitors form a potential divider producing a signal that is proportional to the transmission line voltage.
Both pick-ups are constructed on a printed circuit board (PCB) which forms a small section of the transmission line shield. This ensures mechanical stability, which is essential for accurate repeatable readings.
Digitizing the Signals
Analogue signals are sampled using a high speed analogue to digital converter. The bandwidth of the converters are beyond 300MHz, which allows the Octiv to sample the harmonics of the RF voltage and current as well as the fundamental signals.
Digital Signal Processing
The digital signals are converted from the time domain to the frequency domain using a Fast Fourier Transform (FFT). The results from the voltage and current FFTs are compared to find the phase between the two at each frequency. The two amplitudes and phases are then passed to an averaging algorithm to increase the signal to noise ratio (SNR).
The final stage of the digital processing converts the numbers used in the digital domain to real world values (ie the actual voltage and current values).
Communication
The Octiv communicates measured results to a PC using a USB interface for both communication and power.
Derived Measurements
The sensor measures the complex voltage and current at a single point on the transmission line. The voltage and current measurements can be used to derive power, forward and reflected power.
Plasma RF Power Meter - Octiv Mono (