d note that in this embodiment the field titanium 3 has been cleared using eg 20 1 boe in this case the substrate 5 should be well rinsed to prevent any possible fluorine diffusion in another embodiment depending on desired device geometry it is possible to have a center pad of titanium 3 surrounded by a field of tiw 1 fig2 b as drawn shows center pad tiw 1 surrounded by field ti 3 this variation involves reversing original tiw 1 etch mask polarity from opaque to clear for positive pr 2 fig2 a as drawn shows clear center pad pr 2 covering etched tiw 1 for alignment clarity in this case the contact pad 9 opening shown in fig2 c could be etched in hydrogen peroxide tiw 1 in yet another embodiment depending on desired device geometry it is possible to liftoff additional titanium 3 metal to selectively mask polyimide 4 surface and prevent localized etching load substrate 5 in plasma etcher to remove exposed polyimide 4 in preferred embodiment the plasma etcher should permit independent biasing of substrate 5 and incident ion flux for best profile 7 control and to minimize substrate 5 damage however rf diode system is acceptable and can provide good throughput the initial stage plasma etch is performed in plasma mode at relatively high pressure eg 0 5.