Carl Zeiss SMT's own 2011 technical presentation confirms an EUV mirror surface-figure specification of rms = 0.1nm, corroborating the order of magnitude of the vault's earlier sub-0.1nm roughness figure

A slide deck presented by Carl Zeiss SMT engineers (Olaf Conradi, Peter Kuerz, and co-authors) at the 2011 International EUV Lithography Symposium states, for the NXE:3300 projection optics then in production, "achieved surface quality rms = 0.1 nm" against an internal target for "surface figure." The same deck's mid-spatial-frequency roughness (MSFR) chart shows measured values in the 52–102 picometer RMS range across mirror generations from the NXE:3100 (2004–2009) to the first NXE:3300 mirrors (2011), with the best ("Champion") 3100 mirror at 59 picometers and the first 3300 mirrors at 52–78 picometers — all comfortably at or below 0.1nm (100 picometers) RMS.

This is a primary, named, company-authored technical document — the people who built the mirrors, reporting their own fabrication data — clearing the Tier 1–2 floor a quantitative claim requires (per 00-meta/specs/sources.md). It corroborates the order of magnitude of the "sub-0.1nm RMS roughness" figure in claim-euv-mirror-advantage-is-tacit-know-how-not-patent, which had rested only on a Tier-4 industry explainer and carried an [unverified-quant] flag routed at question-verify-euv-mirror-tacit-knowledge-moat. It also sits alongside claim-zeiss-smt-is-sole-supplier-of-euv-optics-behind-most-advanced-chips as a second, independently-sourced data point on Zeiss's own mirror-making capability.

Two caveats keep this from being a full verification rather than a corroboration: "surface figure" and MSFR are related but distinct optical metrics, both loosely folded into "roughness" in the original claim; and the data are from 2011, describing the NXE:3300 generation specifically, not shown to hold for later High-NA systems. The figure is corroborated for a named historical product generation, not established as an evergreen constant.