VSim Plasma: particle-in-cell simulation for plasma processing

Reshape the chamber or the drive waveform in software and read off the energy and angle of the ions reaching your wafer, while the hardware is still a drawing.

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What VSim Plasma does

VSim Plasma is particle-in-cell plasma simulation software for the discharge inside your process chamber. Every charged species moves as a particle through background gas at your operating pressure. A finite difference solver computes the electromagnetic fields those particles create, and the collisions and reactions between them decide what finally lands on the wafer. Trying a different chamber or chemistry costs you a rerun instead of a rebuild.

Capabilities

Numerical methods

The kinetic species are pushed as particles with cell defined forces, which are found using finite-difference methods. Monte Carlo Collisions and/or Direct Simulation Monte Carlo methods are used to solve the plasma chemistry.

Collisions and reactions

Elastic scattering, excitation and ionization among electrons, ions and neutrals set the shape of the electron distribution. In a working process plasma, that shape is rarely thermal. The reaction set adds charge exchange, excitation decay, three-body recombination and three routes to ionization: impact, field and electron. Surface interactions include sputtering and secondary electron emission.

Geometry and boundaries

Cut-cell algorithms follow a curved wall or focus ring close to its true contour, as opposed to a staircase approximation. Set conducting and dielectric materials in any of several dimensionalities, then decide what each boundary does to a particle: absorb it, reflect it, wrap it periodically, let part of the flux through, or cause emission of another particle.

Scale

From a laptop to high-performance parallel machines. The code’s record includes national-lab supercomputers.

Two packages on one engine

VSim Plasma

The package for semiconductor processing. Magnetron sputtering, DC and capacitively coupled plasmas, ion thrusters and ion sources all fall under it, so one license covers the discharges behind both etch and deposition. Working on a process chamber? Start here.

Works with

Takes in

The chamber geometry, the gas mixture at your process pressure, and the drive conditions. The drive waveform matters more than it looks, because it sets the energy of the ions that do the etching.

Produces

Ion energy and angle distributions at the wafer, plus deposition and erosion profiles for sputtering. Export the distributions as histograms or von Mises-Fisher fits, and Victory Process picks them up to predict the feature-scale profile.

What you can simulate

Plasma wafer etching

Argon ions etching a microelectronics wafer inside a plasma chamber.

Magnetron sputtering

Target erosion and film deposition from a magnetron discharge.

Ion sources

Plasma ion sources, modeled from the discharge outward.

Chamber and reactor design

Compare chamber geometries on how evenly they treat the wafer, with no hardware cut.

Track record and resources

Three supercomputers, one code

Lawrence Berkeley National Laboratory's Perlmutter, The University of Saskatchewan’s Alliance cluster, and the University of Colorado’s Summit supercomputer have all run VSim. If your chamber model outgrows a workstation, the code has already worked at supercomputer scale.

A documented example set

Worked setups for capacitive and DC discharges, ion sources and magnetron sputtering, each with its documentation. Your first run can start from a working case and change one thing at a time.

Try it on the chamber
you actually run

Bring your chamber geometry and the profile problem you can’t close.
That’s the case our engineers model.

Talk to our Technical Experts
Downloads and documentation

Questions about VSim Plasma

What is particle-in-cell plasma simulation?

Particle-in-cell simulation models a plasma as a large population of macro-particles, each standing in for many real ones, moving across a computational grid. Each step, the grid collects their charge, a field solve follows, and the updated fields move the particles. Nothing about the velocity distribution is assumed; it emerges from the run.

When the distribution is non thermal, which is the case wherever it counts in a process plasma. Electrons thin out above the ionization and excitation thresholds, and in the sheath neither species is anywhere near thermal equilibrium. A fluid model would assume the distribution is thermal (Maxwellian).

Collisions among electrons, ions and neutrals cover elastic scattering, excitation and ionization, computed by Monte Carlo collisions and DSMC. VSim also includes impact, field and electron ionization, three-body recombination, charge exchange, excitation decay and sputtering. If your chemistry needs a process that isn't listed, ask before you set up the run.

Yes, that's what the cut-cell method is for. It follows curved walls, focus rings and other chamber features as drawn, in several dimensionalities, with conducting and dielectric regions defined. So you can compare two chamber designs on screen before committing to either one.

Both. It runs on a single workstation and on high-performance parallel clusters, and VSim has run on national-lab and university supercomputers. Before you size hardware for it, check operating system support, GPUs and the license model with our engineers, so the plan matches what ships.

Yes. Evaluations run on your own chamber geometry and process conditions, and a Silvaco engineer works through the first setup alongside you. The result then tells you something about your own process, which is the whole reason to run an evaluation.

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