What is particle-in-cell plasma simulation?

A method that represents a plasma as a large number of computational particles moving through a grid. Each time step the particles deposit charge and current onto the grid, the fields are solved there, and the particles are pushed by those fields. It captures the full velocity distribution rather than assuming one.

When do I need a kinetic model rather than a fluid one?

When the distribution is not thermal, which in a process plasma is most of the time that matters. Electron distributions drop away at ionisation and excitation energies, and at the sheath neither electrons nor ions are in equilibrium. A fluid model assumes a temperature there, which is exactly where the ion energy and angle at the wafer are decided.

Which collision and reaction processes are included?

Elastic, excitation and ionisation collisions between electrons, ions and neutrals, handled by Monte Carlo collisions and DSMC. The published reaction types are impact, field and electron ionisation, electron scatter, charge exchange, sputtering, binary elastic and inelastic, binary reaction, three-body recombination, excitation and decay.

Can VSim Plasma model my chamber geometry?

It is built to. Geometry imports as CAD — STL or STEP — or as GDSII, or can be built in the tool, and Dey-Mittra cut cells on a spatially varying grid represent curved walls and focus rings without stair-stepping them. The worked examples include 2D capacitive and inductive chambers and a wafer with a dielectric focus ring.

Does it run on a cluster or only on a workstation?

Both. The same simulation installs on a laptop or a parallel cluster, distributed over MPI with InfiniBand supported out of the box, on Windows, Linux or macOS. On GPUs the sources disagree: Silvaco’s annual report cites GPU-enablement for plasma simulation, but VSim’s release notes do not document it for discharges. Ask first.

Is there an evaluation licence?

Yes. A 30-day evaluation is available through Tech-X, and every evaluation includes a consultation with one of its physicists, so the first run is set up on your own problem. Requests still go through txcorp.com, as support and licensing do; no Silvaco route has been announced.

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. An FDTD 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 in cell, and FDTD solves the fields around them at each step. Monte Carlo collisions and DSMC carry the plasma chemistry. For regions that don't need the kinetic detail, switch to the charged-fluid, finite-volume option and spend the compute where it counts.
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 sputtering, charge exchange, excitation decay, three-body recombination and three routes to ionization: impact, field and electron.
Geometry and boundaries

Cut-cell algorithms follow a curved wall or focus ring at its true contour instead of 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 or let part of the flux through.
Scale

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

Two packages on one engine

VSimPD · plasma discharge #

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.
VSimPA · plasma acceleration #

Wakefield acceleration, driven by laser or by electron beam, with ionization injection. It shares VSimPD's engine but serves plasma-physics research, not the fab.

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.

See the Plasma family

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

Four supercomputers, one code

The University of Sydney's Artemis, Argonne's Theta, Lawrence Berkeley National Laboratory's Cori and KAUST's Shaheen II 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

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 far from thermal, which is the usual 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 equilibrium. A fluid model would assume a temperature exactly where the ions pick up the energy and angle that shape your etch.

Collisions among electrons, ions and neutrals cover elastic scattering, excitation and ionization, computed by Monte Carlo collisions and DSMC. Reactions include 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.

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

What VSim Plasma does

Capabilities

Numerical methods

Collisions and reactions

Geometry and boundaries

Scale

Two packages on one engine

VSimPD · plasma discharge #

VSimPA · plasma acceleration #