A process for providing a
metal-seeded
liquid crystal polymer comprising the steps of providing a
liquid crystal polymer substrate to be treated by applying an
aqueous solution comprising an
alkali metal hydroxide and a solubilizer as an etchant composition for the
liquid crystal polymer substrate. Further treatment of the etched
liquid crystal polymer substrate involves depositing an adherent
metal layer on the etched
liquid crystal polymer substrate. An adherent
metal layer may be deposited using either electroless metal plating or
vacuum deposition of metal such as by
sputtering. When using electroless metal plating, a
tin(II) solution applied to the liquid
crystal polymer provides a treated
liquid crystal polymer substrate to which the application of a
palladium(II) solution provides the metal-seeded liquid
crystal polymer. The etchant composition comprises a solution in water of from 35 wt. % to 55 wt. % of an
alkali metal salt, and from 10 wt. % to 35 wt. % of a solubilizer dissolved in the solution to provide the etchant composition suitable for
etching the liquid
crystal polymer at a temperature from 50° C. to 120° C. A flexible circuit comprising a liquid crystal polymer film having through-holes and related shaped voids may be formed using etchant compositions as previously described. Etchant solutions may be used to prepare the surfaces of materials for formation of composite structures useful in applications including flexures for hard disk drives.