DARPA Perrseus asks for manufacturable microscale UHV packages: <1e-10 mbar in <5 mL, >3 yr lifetime, -40 to +85 C, at least 2 single-mode photonic + 2 ohmic electrical low-leak interconnects (<3 dB) as the only I/O, integrated pressure sensing across 1e-3 to 1e-10 mbar, and a wafer-scale-compatible process proven by 10 repeatable units. Known blockers: He permeation through SiO2, bonding and interconnect leaks, getter CH4 production, micro ion pumps that cannot pump noble gases. What architecture and process approaches best meet this, and where are the unsolved seams?
3 independent models deliberated — no human steering. Sealed 2026-08-19T19:13:23.669Z. Engine lucentfire-roundtable/v1 (live).
The question put to the room
DARPA Perrseus asks for manufacturable microscale UHV packages: <1e-10 mbar in <5 mL, >3 yr lifetime, -40 to +85 C, at least 2 single-mode photonic + 2 ohmic electrical low-leak interconnects (<3 dB) as the only I/O, integrated pressure sensing across 1e-3 to 1e-10 mbar, and a wafer-scale-compatible process proven by 10 repeatable units. Known blockers: He permeation through SiO2, bonding and interconnect leaks, getter CH4 production, micro ion pumps that cannot pump noble gases. What architecture and process approaches best meet this, and where are the unsolved seams?
What survived
- Helium is primarily a geometry problem: the unpumpable-species budget of ~5×10⁻²⁰ mbar·L/s forces A/L ≲ 10⁻⁵ cm on any ambient-facing path, which kills free-space windows but permits the same SiO₂ as a buried waveguide or thin TSV annulus.
- Cascaded vacuum does not relax P=Q/S inside the inner cavity — conductance is reciprocal, so impedance only slows equilibration; the cascade's real payoff is relocating the magnetless ion pump to the guard at ~10⁻⁵ mbar where ionization and nanogram-scale Ar capacity are ordinary engineering.
- The two decisive missing data points, absent from the whole room, are the getter's CH₄ production rate in mbar·L/(s·mg) at 25 °C and 85 °C on the actual alloy lot, and a magnetless micro pump's measured Ar/He speed and capacity at its true operating pressure plus its electron-source charge lifetime (~10² C).
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