News

Measurement of deposition rates and ion energy distributions using the Quantum system

Learn how metal deposition rates, ionization fraction and energy distribution of ions arriving at a substrate are measured in an asymmetric, bipolar, pulsed DC magnetron sputtering reactor.

Industrial Communication Protocols

Learn about communication protocols and how the Industrial Octiv has been developed to enable fast, reliable, scalable, real-time communication of measurements through ethernet networks.  

Octiv VI Probe Technology - Standards of Calibration

Octiv VI Probe Technology - Standards of Calibration

Abstract

This technical note describes the uncertainty in measurements and standards of calibration for Octiv VI Probe technology. High 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 (VI probe) 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.

Learn more about our Octiv system here

Octiv VI Probe Technology - Theory of Operation

Octiv VI Probe Technology - Voltage | Current | Phase | Impedance

Abstract

This technical note describes the theory and architecture behind Octiv VI Probe technology. The 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.

Learn more about our Octiv system here

Ion angular distribution measurements with a planar retarding field analyser

The Vertex Multi Sensor measures the ion energy distribution as a function of aspect ratio hitting a surface inside a plasma reactor from multiple locations to analyse the uniformity of ion interactions across a substrate.

Abstract

In this application note, we present a novel method which can be applied to a planar retarding field energy analyser (RFEA) for the measurement of ion angular distributions. Ion energy and angular ion distributions play a critical role in plasma assisted etching and conformal deposition processes. Ion impact at wider angles may be required for better step coverage in certain sputter deposition and ion implantation processes while large angle ion impact can be detrimental to anisotropic etch processes. In the early 80’s, Stenzel et al 1, 2 developed a directional RFEA where particles are geometrically filtered through a micro-capillary plate prior to energy analysis. The high aspect ratio (AR) of the holes/channels in the plate allowed them to select particles within a geometric acceptance angle. The Vertex RFEA design has a variable AR, controlled using a potential difference between two grids (see application note VE02). A variable AR controls the ion angular spread passing through the sensor for detection. The Vertex product produces a plot of ion energy distribution versus AR.

Learn more about our Vertex system here

Ion energy and ion flux measurements through high-aspect ratio holes using the Vertex system

The Vertex Multi Sensor measures the ion energy distribution as a function of aspect ratio hitting a surface inside a plasma reactor from multiple locations to analyse the uniformity of ion interactions across a substrate.

Abstract

High aspect ratio (AR) etching is a key process in integrated circuit (IC) fabrication. The manufacture of a 3D NAND memory stack requires structures with an AR > 50 to be created. The key challenge is to create bow-free, straight profiles with minimal twisting. Transport of ions and neutrals to the bottom of these structures can be limited by sidewall shadowing. In particular, ion bombardment of feature sidewalls complicates etching profile control while ion loss to the sidewall reduces ion flux to the bottom of the feature. Only ions with a relatively narrow angular spread, relative to normal incidence, will reach the bottom of high AR features. Ions are accelerated toward the substrate by the sheath electric field perpendicular to the substrate surface. However, ions have some thermal velocity when entering the sheath and therefore have an energy component parallel to the substrate surface. The ratio of the perpendicular to parallel components of the ion energy vector determines the angular distribution.

Learn more about our Vertex system here

Drop by booth #B-110 to meet Impedans at the 20th International Vacuum Congress at the BEXCO Convention Center. We would be delighted to speak with you about your plasma measurement needs.

August 23 - 25, 2016
Busan Exhibition and Convention Center
55 APEC-ro, U-dong, Haeundae, Busan
Booth #B-110

Shailesh is presenting a talk on Thursday 30th June at 11:20am at this year's International Conference on Fundamentals and Industrial Applications of HIPIMS being held in Sheffield on 27-30 June 2016.

"Measurement of deposition rate, ionized flux fraction and ion energy distribution in a pulsed dc magnetron sputtering system using a retarding field analyzer with embedded quartz crystal microbalance. "

Learn more about our Quantum system by clicking here

Matching Network Efficiency

Your company has paid a large sum of money for a piece of complex RF process equipment and your RF power supply is rated to 1% accuracy. That will give you great confidence that the process will be reliable and repeatable. 

However, if 10 – 50% of that accurate power is lost in the matching network does that change things?   Would you like to know how efficient your matching unit is? 

So, even if 50% of the power is lost in the matching unit; you can probably learn to live with that as long as it is the same every time, Right!  But, what if the match efficiency is not constant and changes every time you change the process gas flow, the gas type or the chamber pressure, that would not be so good, would it?

Step 1 - Connect an inline power meter, the Octiv Mono ( mono 1) to the output of a 50Ω load. We are going to measure the range with power applied so make sure the load can handle the power. The power meter is optional but it will be useful if you want to measure the Efficiency of the Network.

The match unit or matching network is a key component in getting power from an RF power supply to a plasma. The output of the power supply has a typical impedance of 50 Ohm. To match this to a plasma or other dynamic load we need a matching network. The matching network plays two key roles i) it presents a reactive impedance equal and opposite to the load so that the reactive components cancel and ii) it matches the real resistance of the load to the 50 Ohms of the RF power supply.

We recently got a returned Octiv sensor with the connector melted and this reminded me of hotspots and flashpoints.

In the world of RF engineering transmissions lines are matched and current and voltage are uniform along the cable. In the plasma world transmission lines are used to carry power to the plasma. A matching network is used to match the power supply to the plasma but the connection, effectively a transmission line from the matching network to the plasma electrode is not matched. I am not an RF engineer but even a physicist knows that there is a reflected wave at the end of the unmatched transmission line.

Drop by booth #737 to meet Impedans at the AVS 62nd International Symposium and Exhibition at the San Jose Convention Center this October. We would be delighted to speak with you about your plasma measurement needs.

October 18 - 23, 2015
San Jose Convention Center
San Jose, CA
Booth #737

This application note looks at a Langmuir Probe used in an etching environment to investigate the phase-shift effect in capacitively coupled plasma discharges by measuring the electron density and electron energy distribution function. Click here to download and read.

In 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. Click here to download and read.

Today's application note introduces a hybrid-dual-HiPIMS system based on the simultaneous combination of dual-HiPIMS and MF discharges. The main body of the study is the time-resolved diagnostics taken using a Semion System during the deposition of Ti–Cu films, revealing the degree of assistance made by the MF discharge. Click here to download and read.

This study used a Langmuir Single Probe to determine the temporal evolution of the oxygen negative ion and electron densities during the offtime of a reactive HiPIMS discharge operating in argon–oxygen gas mixtures. The aim of the study was to add to the knowledge base information about oxygen negative ion dynamics that will help many plasma processing methods. Click here to download and read.

High-power impulse magnetron sputtering (HiPIMS) systems have been previously studied with mid-frequency (MF) plasma excitation, utilizing the “off” period to enhance the deposition rate, decrease the working pressure, and improve HiPIMS plasma generation. Our latest application note looks at the time-resolved ion velocity distribution function (IVDF) in a high-power pulse plasma in three modes of excitation: pure HiPIMS, medium-frequency pulsed bipolar (MF 350 kHz) and hybrid pulsed HiPIMS + MF. Click here to download and read.

Click the video below to see Impedans unique and easy method for switching between single and double Langmuir Probe tips

Click here to explore more about our Langmuir Probe.

Some manufacturing considerations for parameter estimation in pulsed plasma discharges

Stephen Daniels | Dublin City University

Click here to see more from the Pulsed Plasma Diagnostic Workshop.

Click to read the new Theory of Operation for our Semion System. This highly versatile instrument measures ion energy, ion flux, negative ions, temperature and bias voltage at any location inside a plasma reactor, even at the substrate position. The multi-sensor version can also be used to look at uniformity issues that are very common in plasma processes. This gives valuable and unique data to many industries including etching, deposition, ion beam and space plasma.