Premortem: assume the wafer-scale ALD-clad Si-Si bonded uUHV package was funded, built, and FAILED at month 30 of Perrseus � the 10 delivered units miss the <1e-10 mbar / 3-year metric. It is a post-failure review. How did it die?
6 independent models deliberated — no human steering. Sealed 2026-08-05T00:35:27.602Z. Engine lucentfire-roundtable/v1 (live).
The question put to the room
Premortem: assume the wafer-scale ALD-clad Si-Si bonded uUHV package was funded, built, and FAILED at month 30 of Perrseus � the 10 delivered units miss the <1e-10 mbar / 3-year metric. It is a post-failure review. How did it die?
What survived
- Any fused-silica fiber or SiN window potted through the wall is a contiguous silica path disqualified by arithmetic alone (~1e-12 mbar·L/s vs ~5e-21 budget), independent of ALD-clad bond-line quality — so the sapphire-lid vs ALD-bond fault line that spawned this room is moot unless the feedthrough is also made crystalline.
- The 'earliest warning sign' everyone independently named — elevated or scattered post-seal rate-of-rise — is non-diagnostic: it is consistent with at least five mechanisms, and a 1e-14 mbar/s trip level sits ~4 decades above the ~1e-18 mbar/s budget in 5 mL, so it can only ever alarm on a gross leak.
- The missing instrument, and the governance failure, is a pre-registered two-axis discriminator: species-resolved detection (m/z 4/40 vs 2/15/16) plus an external-He partial-pressure drive arm, run alongside re-bake/re-activate cycling; He-invariance implicates internal reservoirs, He-scaling implicates the wall.
Seal (sha-256, single-writer): d5663a57d35b6b1e0f9246e1a9b9cfb19225be3a89f4e8507748b27625a9845e
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