High Performance Polymers, 2nd Edition

15: POLY(IMIDE)S 359

3. Dissolving the PI resin in a solvent,

4. Casting and drying.

Metalized PI films are used in electronic applica-

tions, e.g., for flexible printed circuit boards. Con-

ventional techniques for the fabrication use adhesive

bonding to a copperfoil. However, the demandfor high

density packaging of electronic apparatuses requires a

further reduction in the thickness of these substrates.

It is possible to sputter metal particles into the surface

of the PI film at a thickness of 20 nm, which forms the

intermediate layer for subsequent formation of a con-

ductive layer of copper or a copper alloy [119,120].

PI resins find use as coverlays.