D32 — Escape planning v1 as reserved corridors

Decision

Escape planning v1 is reserved corridors (perimeter out, dog-bone for inner SMD balls) checked by the normal router, not a min-cost-flow pre-route

Alternatives

Min-cost-flow escape routing first (doc 05 §3)

Reason

The BGA failures were mostly infeasible under the fixture rules or time-starved strict passes; corridors fix the "channel taken first" case cheaply (logicbone +26, decelerator +33 at a fixed budget) and cannot create violations. MCF stays open for deep arrays