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Vertex - the theory behind ion current as a function of angle

Ion angular distribution measurements with a planar retarding field analyser

Ion angle determination with current derivative
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

New Vertex application note

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

Vertex Multi Sensor
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

Join us at IVC-20 Busan Korea, August 23-25

Visit Impedans at booth B-110 - IVC-20 BEXCO Center Busan, Korea, August 23-25

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

Mike Hopkins and David Gahan graduate from ISE's leadership programme IPOready

Impedans graduate ISE's IPOready programme

HIPIMS 2016, Shailesh Sharma is presenting...

Shailesh Sharma is giving a talk at HIPIMs 2016, Thursday 30th June, 11:20am

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

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?

RF Matching Network Range

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.

Matching Network Quality

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.

Hot spots and flash points

Hot spots and flash points rf technology

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.

AVS 62nd International Symposium and Exhibition

Meet Impedans at booth #737, AVS 62nd International Symposium and Exhibition

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

Langmuir Probe used in experimental and numerical investigations of the phase-shift effect in capacitively coupled plasma discharges

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.

Impedans Octiv used in a study demonstrating a simple radio-frequency (RF) power-coupling scheme for a micro atmospheric pressure plasma jet

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.

Semion used in a study of the effect of mid-frequency discharge assistance on dual-high power impulse magnetron sputtering

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.

Semion Retarding Field Energy Analyser (RFEA) used in a study to form Ti–Cu thin films with regard to controlling the copper release

Langmuir Single Probe used in determining the temporal evolution of negative ion density in the afterglow of reactive HiPIMS of titanium in an argon/oxygen gas mixture

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.

Semion RFEA used to investigate reactive HiPIMS + MF sputtering of TiO₂ crystalline thin films

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.

Langmuir Probe Tip Operational Video

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.


Solar Cell Breakthrough

Pulsed Plasma Diagnostic Workshop with Stephen Daniels

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.


Theory: Semion System | Retarding Potential Analyser | Retarding Field Energy Analyser

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.

Pulsed Plasma Diagnostic Workshop with Ralph Bandorf

Investigation of HiPIMS Discharges

Ralph Bandorf | Fraunhofer IST

 

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


Pulsed Plasma Diagnostic Workshop with Carles Corbella

Elementary surface processes during plasma pre-treatment of polymers and during target poisoning in reactive magnetron sputtering

Carles Corbella | RWTH Aachen University

 

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


Langmuir Probe - Theory of Operation

Click to read our new Langmuir Probe Theory of Operation that outlines the unique features and functions of our system for characterising bulk plasma parameters. You can also download a PDF for offline viewing and reference.

Pulsed Plasma Diagnostic Workshop with Arutiun P Ehiasarian

Plasma diagnostic challenges in the High Power Impulse Magnetron Sputtering (HiPIMS) environment

Arutiun P Ehiasarian | Sheffield Hallam University

 

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


Laser Plasma Accelerator World Record

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