= Solution
\b[A compatible, reaction-limited <chemical vapor deposition> process can give nearly conformal coverage of tops, sidewalls and floor.] Gas-phase precursors reach recessed surfaces and react there; the coating is not restricted to the line of sight of a solid source. The result is a continuous film over the resist pattern, which is unfavorable for ordinary <lift-off process>.
If each wall receives the same $0.20\,\mathrm{\mu m}$ coating as a horizontal surface, the nominal $0.50\,\mathrm{\mu m}$ gap narrows to
$$
\boxed{0.50-2(0.20)=0.10\,\mathrm{\mu m}.}
$$
That numerical result is the conformal idealization. Precursor depletion or rapid surface reaction can instead give poorer bottom coverage or premature closure near the mouth. Actual silver chemistry and deposition <temperature> must also be compatible with the resist; a process that decomposes the resist does not preserve the illustrated mask.
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