The Octiv Suite RF diagnostic (VI Probe) is an in-line RF voltage, current, phase, harmonics and plasma diagnostic system. It can measure all the parameters of RF power, break them down to their individual components and reconstruct the waveform of multiple fundamental frequencies simultaneously. This cutting edge system can also measure plasma parameters such as ion flux by using the RF electrode as a sensor. The Octiv Suite is truly in a class of its own when it comes to power delivery into a plasma reactor.
The Octiv Suite measures voltage, current, phase, impedance and harmonics and the measurements can be viewed from a PC or direct to the meter unit.
The Octiv Suite RF diagnostic (VI Probe) system allows users to measure a number of fundamental frequencies and extract all the harmonic information of each parameter measured simultaneously while reconstructing multiple waveforms.
The Octiv Suite is a unique leading edge technology to allow scientists evaluate complex inter-dependencies of RF parameters in areas such as plasma process performance. The Octiv Suite measures and displays the complex waveform. The software extracts and analyses the key RF parameters such as voltage, current and phase of all the complex components that make up the waveform.
The Octiv Suite RF diagnostic (VI Probe) can be used to diagnose plasma parameters such as ion flux, plasma resistance and non-linear sheath impedance. The Octiv Suite will characterise a non-linear load with multiple fundamental frequencies, high harmonic and intermodulation components. The Octiv Suite unique software algorithm analyses accurately the phase of multi-frequency, harmonic and intermodulation components and allows reconstruction of individual component waveforms or the multi-frequency combined waveform. The Octiv Suite is the first and only product on the market that can accurately analyse multiple fundamental frequencies, harmonic and intermodulation components in frequency agile (FM) applications and pulsed power (AM) applications (Time resolution 1μs).
The Octiv Suite RF diagnostic (VI Probe) helps the user understand new processes such as multi frequency or pulsed plasma applications. It analyses RF waveforms to measure plasma parameters such as ion flux. Wave form reconstruction with The Octiv Suite supports a better understanding of differences in load impedance. This is crucial for applications such as chamber matching and tool to tool comparisons. The Octiv Suite delivers the capability to analyse process endpoint, and multivariate fault detection and classification using harmonic analysis. RF parameter measurement helps with process fingerprinting. A unique feature of The Octiv Suite is the ability to analyse the power spectra of a process which is a key parameter of multi-frequency applications. Impedance analysis is used to detect poor RF connections, worn components and changes in process chemistry. The Octiv Suite gives you the confidence to analyse multi-frequency components and their impact on the process.
Time Averaged Measurements
This provides an average over time of voltage, current and phase.
Time Resolved Measurements
This allows the user to synchronise the V,I & Phase measurements with an external synchronisation signal. The user can then obtain detailed information on the ion energy distribution as a function of time or phase through the synchronisation pulse period. Typically the pulse period would be on a timescale of milliseconds to microseconds.
Time Trend Measurements
This allows the user to obtain information on the variation of the voltage, current and phase as time progresses through a particular process. This feature does not require external synchronisation and the timescales involved can be in range of seconds to hours.
Smith Chart Measurements
Monitor the Load Impedance as it is displayed on a Smith Chart and track Impedance variations throughout the process cycle.
Octiv Suite Pulsed Power Measurement
The Octiv Suite measures the pulsed power time profile at micro second resolution while maintaining a very high degree of accuracy (1%). It measures a single frequency at a time and 15 of its harmonics. The user can select the frequency they wish to analyse from a drop down menu of 5 frequencies or the user can request 5 specific frequencies at the time of order.
Meter View
View process parameters as they are acquired by the sensor. This feature provides a useful way of monitoring RF power delivery during process hardware setup and installation. Data can be recorded to a file for analysis.
Smith Chart View
Monitor the Load Impedance as it is displayed on a Smith Chart and track Impedance variations throughout the process cycle.
Harmonic View
With the unique Harmonic View, the voltage and current harmonics of the delivered signal may be monitored in real time. Observe the harmonic content of the delivered power, and intuitively identify harmonic components which may be sensitive to process variations.
Time Trend View
Use the Time Trend view to monitor each RF parameter in real-time. Visualise time-series data as it is acquired. Acquire an overview of each parameter during the process run and monitor run-to-run or chamber-to-chamber variations.
Compact Design
The Octiv Suite is designed to be compact and easy to install. It is mounted between the match unit and the plasma chamber to give the most accurate measurement of the RF delivery into the plasma chamber.
Frequency Agility
The Octiv Suite allows the user to accurately measure the RF parameters while tracking a rapidly varying fundamental frequency. For example: in variable frequency tuning to match the plasma.
Software Application Programmers Interface (API)
A comprehensive API is provided with the sensor to facilitate integration with 3rd party software applications. Sensor initialisation, configuration, and data transfer functions are easily implemented on all of the common software platforms.
Communications Interface
The standard Octiv communications interface is USB 2.0, which provides power to the sensor, and supports sensor configuration and data transfer activities in a laboratory environment. For integration with industrial equipment and manufacturing automation systems, alternative communications interfaces are available and based on RS-232 or Ethernet. Electrical isolation ensures the reliable transfer of data even in RF environments.
| Voltage Range | 20 – 3000 Vrms |
| Current Range | 0.1 – 20 Arms |
| Phase Range | ± 90º |
| Harmonic (Voltage, Current and Phase) | Up to 15 Harmonics |
| Frequency Range | 350 kHz - 300 MHz |
| Fundamental Frequencies | 5 Simultaneous |
| Impedance | 1 to 500Ω |
| Power Real, Forward and Reflected (Watt) | 200mW to 12KW |
| Power Real, Forward and Reflected (dBm) | 25dBm to 70dBm |
| Ion Flux (based on 300mm electrode) | 1 A/m² to 100 A/m² |
| Plasma Resistance | 1 to 500Ω |
| Non Linear Sheath Impedance | .1 to 500Ω |
| Voltage Time | 1μs |
| Current Time | 1μs |
| Phase Time | 1μs |
| Harmonic (Voltage, Current and Phase) Time | 1μs |
| Frequency Time | 1μs |
| Impedance Time | 1μs |
| Power Real, Forward and Reflected (Watt) Time | 1μs |
| Power Real, Forward and Reflected (dBm) Time | 1μs |
| Voltage Accuracy | ± 1% |
| Current Accuracy | ± 1% |
| Phase Accuracy | ± 1º |
| Harmonic (Voltage, Current and Phase) Accuracy | ± 5% |
| Frequency Accuracy | ± 10kHz |
| Impedance | ± 1% |
| Power Real, Forward and Reflected (Watt) | ± 1% |
| Power Real, Forward and Reflected (dBm) | ± 1% |
| Voltage Resolution | 0.25V |
| Current Resolution | 10mA |
| Phase Resolution | 0.01° |
| Harmonic Voltage Resolution | 0.25V |
| Harmonic Current Resolution | 10mA |
| Harmonic Phase Resolution | 0.01° |
| Frequency Resolution | 1kHz |
| Impedance Resolution | ± 1% |
| Power Real, Forward and Reflected (Watt) Resolution | ± 1% |
| Power Real, Forward and Reflected (dBm) Resolution | ± 1% |
| Connectors | BNC-Female, BNC-Male, HN-Female, HN-Male, LC-Female, LC-Male, N-Female, N-Male, SMA-Female, SMA-Male, 7/16 Jack, IEC Type 169-4, 7/16 Plug, IEC Type 169-4, Mini UHF-Female, UHF-Female, UHF-Male, 1-5/8" EIA Fixed, 7/8" EIA, TNC-Female, TNC-Male, and Open Term. #10-32 Nut |
| Dimensions | 70mm x 107mm x 55 | Custom designs upon request |
| Number of fundamentals | (F0) Maximum of 5 simultaneously |
| RF Power | Max 12.5 kW (limited by connector) |
| Operating Temperature | 0 to +40°C (32 to 104°F) |
| Storage Temperature | -20 to +80°C (-4 to +176°F) |
| Uniformity | 2% Maximum |
| Harmonic Content | Measured (No Limit within Range) |
| Connectors | All Standard Connectors Available |
| Sensor Impedance | 50Ω |
| Certification | CE mark |
| Calibration Cycle | 12 Months |
| Operating System | Windows 2000 / XP / Vista / Windows 7 / Windows 8 / Windows 10 |
| Impedance | 0Ω to 5,000Ω |
| Pulsed Repetition Frequency | 10Hz to 100KHz |
| Voltage | 20V to 3,000V |
| Current | 0.1A to 100A |
| Phase | ±90º, ±180º |
| Power Frequency | MF (350kHz to 1MHz) • RF (1MHz to 100MHz) |
| Operating System | Windows 2000 / XP / Vista / Windows 7 / Windows 8 / Windows 10 |
| Connectivity | Ethernet Web Service Protocol* |
*EtherNet/IP and EtherCAT available on request
| The Octiv Suite used in Atmospheric applications |
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Impedans Octiv used in a study demonstrating a simple radio-frequency (RF) power-coupling scheme for a micro atmospheric pressure plasma jetAbstractIn this paper, the authors demonstrate a simple radio frequency (RF) power-coupling scheme for a micro atmospheric pressure plasma jet (μAPPJ) based on a series LC resonance, with the discharge gap being part of the resonant element. The Impedans Octiv was used in the experiment. |
| The Octiv Suite used in Dusty Plasma applications |
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| Coming soon |
| The Octiv Suite used in Plasma Etching applications |
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| Coming soon |
| The Octiv Suite used in PECVD applications |
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Ion flux as an alternative deposition rate parameterAbstractThe external parameters which define plasma polymerization experiments (RF power and precursor flow rate) are unable to reproduce plasma polymer films by means of transfer between geometrically different reactors. This has been proven through the use of a geometrically varying parallel-plate electrode reactor. With constant RF power; ion flux and power coupling efficiency measurements demonstrate how variable plasma properties are. Manipulation of these parameters has been shown to be a more useful way of defining plasma polymerization processes. |
| The Octiv Suite used in Space Plasma applications |
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| Coming soon |
| The Octiv Suite used in Plasma Sputtering applications |
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| Coming soon |
| Technical note |
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Octiv VI Probe - Theory of OperationAbstractThe Octiv VI probe is an advanced RF voltage and current sensor, which can provide real-time information on complex loads. Real-time information the Octiv provides includes voltage, current, phase, power and impedance on all harmonics of a chosen frequency simultaneously, as well as transmission line parameters such as forward power, reflected power, standing wave ratio (SWR) and reflection coefficient. The Octiv sensor was designed to meet the need for post-match voltage and current measurements in RF excited plasma processes. |
OCTIV - Standards of CalibrationAbstractHigh power radio-frequency (RF) voltage and current sensors need to be accurately calibrated to a traceable standard. Calibrating to high accuracy can be the most challenging aspect of high power, voltage-current sensor manufacture. This is due to the many sources of error in any calibration process. If the calibration is performed accurately and correctly, then most errors can be characterized and removed. |
The Octiv Suite is part of a range of products which measure the parameters of plasma power delivery. These parameters include; real power; forward power; reflected power; impedance; voltage; current; phase angle; harmonics and ion flux. The Octiv Suite is also capable of reconstructing the waveforms of multiple fundamental frequencies simultaneously. The measurement functionality of the Octiv Suite extends to time-averaged, time-resolved and time-trend measurements.
Development of the Octiv Suite was necessary due to the over simplicity of its predecessor, directional coupler technology, which measured RF power. This technology, which was developed in the 1940’s, measures a forward wave and reflected wave in a transmission line. By dividing the square of these figures by the transmission line rated impedance, the power forward and power reflected can be calculated. While this technology is still widely used in plasma monitoring, it has a number of technical limitations and only works when:
It is also noted that solely monitoring power is insufficient for modern plasma applications and knowledge of wafer parameters is necessary.
The development of technology such as the Octiv Suite is necessary because of the significance of knowing the exact shape of the current and voltage waveforms at the wafer surface. This can be achieved through the installation of a well characterised and calibrated VI probe after the match unit. As the complexity of the RF systems increases, such as in systems that are pulsed, multi-frequency and frequency tuned, the mounting of a VI probe becomes more critical.
When the voltage and current are monitored as complex parameters in the full frequency domain, power and other parameters can be measured in a large range of plasma applications. This brings a number of advantages:
However despite these advantages, when measurements are taken in this manner, the data analytics process can become extremely complex.
Figure 1: Pulsed time resolution
Figure 2 below shows how the Octiv Suite works to capture waveforms. A simple loop is used to pick up current from the RF magnetic field, with voltage from the E field being collected by a capacitor. Any imperfections in these pickups are calibrated out of the system. RF bias forces the capacitively coupled probe potential to the self-biased potential (more negative). By sending a pulsed RF bias the probe can be charged to the self-bias potential when it is ‘on’. At ‘off’ periods, this potential can be discharged. This produces a voltage-current characteristic measurement similar to Langmuir probe results. This system is highly applicable to plasma deposition applications with insulating layers over the electrode/probe surface. The current and voltage measurements are turned into digital format with 14 bit accuracy. When this is fed into a field programmable gate array (FPGA), a one shot signal is collected in a few seconds.
Figure 2: Octiv Suite waveform capture
Once this single shot is collected by the FPGA, a Fast Fourier Transform (FFT) is performed.
Figure 3: Octiv data analysis - FPGA
Following this process the digital oscilloscope is used. The frequency domain is now broken into ranges that are selected by the user. The strongest frequency in each range, Fr₁ and Fr₂, is now sought. Once all of the data is collected, it is sent to two or more digital oscilloscopes. One is activated at Fr₁ and the other at Fr₂. Extra frequencies are used if required. The procedure is repeated with the collection of a second data set, and the process follows the same pattern. No data is lost as it is all stored in the digital oscilloscopes.
The results displayed in Figure 4 below are the average magnitude (FFT) of the fundamental and first 4 harmonics of the voltage (V) and the current (I) at 13.56MHz. The blue data set represents the measurements from the Spectrum Analyser while the red data set represents the measurements from the triggered oscilloscope. These measurements are averaged over 100 data sets, which is approximately 1ms. It is noted that unwanted data such as noise, inter-modulation and aliased signals are cancelled in oscilloscope mode.
Figure 4: Typical VI results
The VI characteristic is determined by an algorithm displayed below. This algorithm is applicable at multiple time steps across the waveform for a variety of voltage resolutions.
Where -Ip is the constant ion current to the electrode;
is the step voltage electrode resistance at the measured impedance;
is the step voltage time varying capacitance at the measured impedance and
is the time dependant voltage derivative. The time steps and voltage resolution v’ are displayed in the figure below. The voltage resolution determines the bin size of the voltage when measuring the voltage waveform. Each time step is representative of the time period the waveform takes to return to voltage v’ having passed it previously. While the voltages are equal in magnitude, they are opposite in direction.
Figure 5: Time step and voltage resolution graphic
Implementation of this algorithm across to voltage waveforms produces an IV curve similar to that shown in Figure 6. This sample data was taken at a capacitively coupled electrode in an ICP reactor. The ion flux extracted from analysis of this IV has been independently verified by Langmuir probe measurements.
Figure 6: Typical VI curve obtained from Octiv Suite
| Download the Octiv Suite Theory of Operation in PDF format |
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 Theory of Operation: Octiv Suite |
M Hopkins, D Gahan
Published 26 Sept 2014
The Octiv Suite is part of a range of products which measure the parameters of plasma power delivery. These parameters include; real power; forward power; reflected power; impedance; voltage; current; phase angle; harmonics and ion flux. The Octiv Suite is also capable of reconstructing the waveforms of multiple fundamental frequencies simultaneously. The measurement functionality of the Octiv Suite extends to time-averaged, time-resolved and time-trend measurements.
Download at Theory of Operation: Octiv Suite
P.D. Maguire, C.M.O. Mahony, D. Diver, D. Mariotti, E. Bennet, H. Potts, D.A. McDowell
Published 3 Oct 2013
The introduction of living organisms, such as bacteria, into atmospheric pressure microplasmas offers a unique means to study certain physical mechanisms in individual microorganisms and also help understand the impact of macroscopic entities and liquid droplets on plasma characteristics. We present the characterization of an RF-APD operating at 13.56MHz and containing microorganisms in liquid droplets emitted from a nebulizer, with the spray entrained in a gas flow by a gas shroud and passed into the plasma source. We report successful microorganism injection and transmission through the plasma with stable plasma operation of at least one hour. Diagnostics include RF electrical characterization, optical emission spectrometry and electrostatic deflection to investigate microorganism charging. A close-coupled Impedans Octiv VI probe indicates source efficiencies of 10 to 15{\%}. The introduction of the droplets/microorganisms results in increased plasma conductivity and reduced capacitance, due to their impact on electron density and temperature. An electrical model will be presented based on diagnostic data and deflection studies with input from simulations of charged aerosol diffusion and evaporation.
Online at Abstract ID: BAPS.2013.GEC.MR1.59
Andrew Michelmore, Christine Charles, Rod W. Boswell, Robert D. Short, and Jason D. Whittle
Published 12 June 2013
External parameters (RF power and precursor flow rate) are typically quoted to define plasma polymerization experiments. Utilizing a parallel-plate electrode reactor with variable geometry, it is shown that these parameters cannot be transferred to reactors with different geometries in order to reproduce plasma polymer films using four precursors. Measurements of ion flux and power coupling efficiency confirm that intrinsic plasma properties vary greatly with reactor geometry at constant applied RF power. It is further demonstrated that controlling intrinsic parameters, in this case the ion flux, offers a more widely applicable method of defining plasma polymerization processes, particularly for saturated and allylic precursors.
Online at ACS Appl. Mater. Interfaces, 2013, 5 (12), pp 5387–5391 DOI: 10.1021/am401484b
Andrew Michelmore, David A. Steele, David E. Robinson, Jason D. Whittle and Robert D. Short
Published 23 May 2013
Film thickness and functional group retention are routinely measured parameters for plasma polymers. It is known that other parameters such as density, solubility and mechanical properties can affect the performance of the plasma polymer film, however such parameters are not often measured; nor is there any understanding of the link between the mechanisms of film growth and these properties. In this investigation we produced thin films from three classes of commonly used plasma polymers (hydrocarbons, glymes and carboxylic acids). By choosing the monomer structure and applied RF power, the dominant mechanism of film growth was varied between ionic deposition and neutral grafting. The density, solubility and modulus of the resulting films were then measured by atomic force microscopy. Films grown from saturated monomers had higher moduli, were less soluble, and surprisingly had lower density compared to their unsaturated analogues. The results demonstrate that cognizance of the mechanism of film growth allows the physical properties of the film to be tailored for specific applications.
Online at Soft Matter, 2013,9, 6167-6175 DOI: 10.1039/C3SM51039E
Andrew Michelmore, Petra Gross-Kosche, Sameer A. Al-Bataineh, Jason D. Whittle, and Robert D. Short
Published 2 February 2013
It has been shown that both ions and neutral species may contribute to plasma polymer growth. However, the relative contribution from these mechanisms remains unclear. We present data elucidating the importance of considering monomer structure with respect to which the growth mechanism dominates for nonfouling PEG-like plasma polymers. The deposition rate for saturated monomers is directly linked with ion flux to the substrate. For unsaturated monomers, the neutral flux also plays a role, particularly at low power. Increased fragmentation of the monomer at high power reduces the ability of unsaturated monomers to grow via neutral grafting. Chemical characterization by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) confirm the role that plasma phase fragmentation plays in determining the deposition rate and surface chemistry of the deposited film. The simple experimental method used here may also be used to determine which mechanisms dominate plasma deposition for other monomers. This knowledge may enable significant improvement in future reactor design and process control.
Online at Langmuir, 2013, 29 (8), pp 2595–2601 DOI: 10.1021/la304713b
Head of Engineering Logic Conductor Etch | Applied Materials, USA