Lithography
Computational lithography and Process Proximity Compensation
What is computational lithography?
Computational lithography is the software that predicts how a mask pattern will print on a wafer and changes the
mask so the printed result matches the design. Process proximity Compensation is its core step. It models how
exposure, resist and etch distort each feature, shifts mask edges to offset that distortion, then checks the
corrected mask in simulation.
The problem
The wafer doesn’t print what you drew. Below the exposure wavelength, diffraction, resist and etch each drag an edge off target. Lines thin. Corners round. Line ends pull back. A perfect layout can still produce the wrong silicon.
What the software does
It predicts that drift with a model calibrated on your silicon, corrects the layout, and simulates the result back before any data reaches the mask shop.
When you use it
When you qualify a new node and need to know whether a layer can print at all. At tape-out, on every critical layer. And in a yield ramp, when one layer keeps missing its critical dimension and nobody can say why yet.
Process Proximity Compensation (PPC)
Silvaco added Process Proximity Compensation from Cadence in March 2025.
DimensionPPC handles curvilinear masks.
Process Proximity Compensation (PPC)
Builds and verifies the mask your layout needs.
- Third-generation suite designed for correct-by-construction OPC, with patented optimization
- Source and source-mask optimization with hybrid SRAF placement
- Pipelined, distributed runs on general-purpose hardware; recipes by GUI or script
DimensionPPC
Curvilinear correction for layers that rectilinear masks can't print cleanly.
- Curvilinear mask synthesis and optimization
- Simulation-based verification of the curvilinear mask
- Mask rule checks written for curvilinear shapes
Where holding the pattern gets hard
Same physics everywhere. What changes is which distortion eats your error budget.
MEMS and sensors
Deep etches, extreme aspect ratios
Compound semiconductors
Resist on non-silicon substrates
Foundries, nodes, formats and platforms
What it runs on, and what it runs against. Where nothing is published, this says so.
Foundries and nodes
PPC runs in production from large geometries to the most advanced processes. The PDK table covers Silvaco’s analog and custom IC tools; ask us directly about lithography coverage.
Operating systems and compute
Synthesis and verification are pipelined across general-purpose hardware, so a full-layer job spreads over your cluster.
Named customer work
DRAM
Curvilinear OPC
Micron
Presented curvilinear OPC on DimensionPPC for DRAM layers, covering mask synthesis, simulation-based verification and mask rule checks.
Nobue Kosa, Member of Technical Staff, Advanced Mask Development, Recipe and Tool Development, Micron
Lithography and TCAD process simulation
Lithography settles which shapes reach the wafer. TCAD process simulation picks them up from there, through etch, deposition and implant, and into a working device.
Lithography papers and sessions
Read any of it without filling in a form.
Conference session
2026
Curvilinear OPC Applications
Micron's curvilinear OPC work on DRAM layers, using DimensionPPC.
Licensing and support for lithography tools
The questions that come before a purchase order. Where the published answer
covers the other product families but not this one, that is said rather than glossed.
Licensing options
Time-Based Licensing: floating seats on terms of one to three years, with updates and technical support in the fee.
Installation and OS support
Licenses run from a server on your network; the installation guide covers setup.
Documentation
User manuals, reference guides and release notes for PPC and DimensionPPC.
Support portal
File a case and follow its status in the portal; access needs a current maintenance contract.
Talk to our technical experts
about one layer
Bring the layer, its node and whatever metrology you have.
An application engineer will scope the calibration with you.
Lithography questions
What is process proximity compensation?
Process proximity compensation (PPC) makes a printed feature match its drawing. Exposure, resist and etch each move a feature's edges, so a line never prints exactly as drawn. PPC predicts that movement and pre-distorts the mask by the opposite amount.
How is PPC different from OPC?
Optical proximity correction (OPC) corrects for what the optics do during exposure. PPC also accounts for resist, etch and mask effects, which shift the final dimension too. Silvaco's Process Proximity Compensation is an OPC suite whose process model covers that wider set, so it corrects toward the dimension you'll measure.
What is computational lithography used for?
Computational lithography makes sub-wavelength features print correctly, which at an advanced node means every critical layer. Teams rely on it while qualifying a node, while preparing mask data for tape-out, and when a yield ramp stalls on a layer that won't hold its dimension.
How is a lithography model calibrated?
Against your own measurements. You print test patterns, measure them with CD-SEM or other metrology, and adjust the model until its simulation reproduces the wafer. Silvaco's predictive process model fits resist, etch and mask behavior this way, so it describes your process, not a generic one.
How does lithography connect to Silvaco TCAD?
They sit on either side of the same wafer. Lithography sets the printed pattern; Silvaco TCAD, including Victory Process, models what the fab does to it next. Both belong to Silvaco's AI-Driven Manufacturing unit alongside FTCO, solution platform
Which foundries and nodes are supported?
Silvaco's PDK table lists support for its analog and custom IC tools. Lithography sits outside it, so for a mask flow the useful question is whether your layer type has been corrected before. Ask us that.
Can it run on a GPU?
Published so far: PPC distributes synthesis and verification across general-purpose hardware. Share your cluster size and layer count and we'll size a run for you.
Is it available for university research?
Silvaco's University Program licenses its tools to more than 200 universities for research and teaching, separately from commercial sales. Contact the program with your group's project to check.