A good way to promote the adhesion of parylene to oxide and to ensure
its survival in KOH etching solution is to melt and recrystalize
parylene.

This is has been demonstrated by Lo and Tai (NEMS 2007).
To get molten parylene, all you need to do is to bake parylene above
its melting point in an oxygen free environment and to cool it down
slowly.

Although A174 adhesion promoter does improve adhesion of parylene to
oxide, the resulting adhesion is not strong enough for KOH and TMAH
etching.

        --lo