SIGNOFF

Assemble a Reproducible Signoff Evidence Package

A tapeout decision is a set of versioned evidence, not a green dashboard. Educational open-source DRC/LVS/RC/IR runs are valuable cross-checks, while qualified foundry decks, extraction, reliability rules, and customer signoff criteria remain authoritative.

Inputs

Final layout/netlist, fill state, and exact release manifest
Qualified multi-corner libraries, RC tech files, and SDC
Foundry-approved DRC/LVS/antenna/reliability decks and waiver policy

Method

Freeze hashes for layout, netlist, constraints, libraries, extraction inputs, decks, tool versions, and run settings before final analysis.
Extract parasitics at each required corner and run propagated-clock STA for setup, hold, recovery/removal, pulse width, and unconstrained-path review.
Run the qualified physical-verification decks and triage every DRC, LVS, antenna, density, and connectivity result to disposition.
Run IR/EM with approved activity, package, voltage-source, temperature, and lifetime assumptions; correlate hotspots to layout ownership.
Review only bounded, justified waivers; issue a release matrix listing each check, scenario, result, owner, and reproducible command manifest.

Deliverables

Corner/mode STA summary with full violation disposition
Qualified DRC/LVS/antenna/extraction and IR/EM reports
Immutable release manifest and signoff matrix

Pitfalls

Using an STA netlist or SPEF that no longer corresponds to the post-fill layout verified by LVS breaks signoff correlation. Keep the RC corner and extraction setup consistent with each corresponding STA scenario.
Open-source checks can reveal integration defects but cannot certify compliance with a proprietary foundry deck or undisclosed chip requirements.

Sources

OpenLane Architecture ↗
OpenLane · Open-source RTL-to-GDS stages and checks

SkyWater SKY130 Parasitic Layout Extraction ↗
SkyWater PDK · Parasitic resistance and capacitance extraction rules

IR Drop Analysis ↗
OpenROAD · Static IR/EM and floating-grid checks

Debugging timing ↗
OpenSTA · Constrained and unconstrained timing reports