Detailed routing
Beginner
The exact pass: drawing every wire in its real lane, with every connection and every manufacturing rule checked.
Novice
The second, exact pass of routing. It draws every wire and via as a real shape on the tracks, connects to the actual pin shapes of each cell, and repairs every broken manufacturing rule. Its output is the finished wiring, written as a DEF file.
Expert
Typically A* search on the track grid inside small regions, followed by many search-and-repair iterations that rip up nets near rule-violation markers and reroute them with rising costs. Getting the violation count to zero is its main runtime and schedule risk.
Explained in Routing (Design Flow).
See also: Global routing, Design rule checking (DRC), Rip-up and reroute.