Vertex Single Sensor - Ion Energy Distribution as a Function of Aspect Ratio

The Vertex Single Sensor from Impedans measures the ion energy distribution as a function of aspect ratio of ions that hit a surface within a plasma reactor. This exclusive plasma characterization tool is also capable of measuring the ion flux, ion energy, and bias voltage.


  • Simple to install
  • Small footprint
  • Resistant to high RF bias
  • Resistant to high temperature
  • Substrate bias compatible


  • Fundamental research
  • High aspect ratio processing
  • Model validation
  • Equipment design
  • Process development


The Impedans Vertex Single Sensor quantifies the ion energy distribution as a function of aspect ratio, ion flux, ion energy, Vdc, and negative ions at a surface within a plasma. The sensor is extensively used in several applications in industry and research, such as ion beams, plasma etching, and plasma sputtering for plasma interaction analysis and plasma characterization.

The Vertex Single Sensor saves users precious time in verifying models, forming new processes, and in experiments that use plasma, plasma research, and plasma tool design.

The Vertex Single Sensor is placed in a 19″ rack-mounted electronics unit, vacuum feed-through, and a sensor holder positioned at any place inside a plasma or beam chamber. The location can even be a DC or RF powered electrode and can utilize a replaceable Button Probe sensor. The electronics unit links to a PC or a laptop, and uses the Vertex intelligent software suite.

The Vertex Single Sensor has several holder options from 50 to 450 mm, based on the user’s application. Users can choose a 50 mm sensor and physically shift the sensor to measure in various chamber locations.

In certain applications, users can choose a sensor holder to suit the size of their electrode or their substrate holder. In this case, the sensor is positioned at a particular location such as the center of the holder plate.

The Vertex Single Sensor enables users to alter their beam source location or plasma input parameters in real time to determine the ideal ion aspect ratio for a particular total ion energy and ion flux in their application. The system also performs useful measurements such as ion energy, the energy and flux of negative ions and bias voltage.

Although the Vertex System is not used on the process side of plasma manufacturing, it has been used to quantify side wall pattern in etch, researching new processes, elastic scattering to assist with chamber-to-chamber matching, beam divergence, and fault detection, in an offline setting.


Measuring Ion Energy Distribution in a Plasma Reactor

Image Credit: Impedans

Plasma Parameters Measured

  • Ion flux (single location)
  • Ion energy as a function of aspect ratio (single location)
  • Negative ion (single location)*
  • Bias voltage Vdc (average)

Measurement Functionality

Time-Averaged Measurements

This measurement offers an average over time of the ion angular and energy distribution that reaches the substrate position.

Time-Resolved Measurements

Users can use this measurement to synchronize the ion energy distribution measurements with an external synchronization signal. Then, they can get complete information on the ion angular and energy distribution as a function of phase or time during the synchronization pulse period*. Usually, the pulse period is on a timescale of milliseconds to microseconds.

*Note: Only in standard energy mode, for pulsed plasmas, with Vertex mounted on a floating or grounded electrode.

Time-Trend Measurements

This measurement enables users to acquire information on the changes in the ion energy distribution as a function of aspect ratio as time advances in a specific process. This feature does not necessitate external synchronization, and the involved timescales can vary from seconds to hours.

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