How to build a RF MEMS on PCB (Rogers 4003c or RT/Duroid 5880)

Hi,

I am struggling to build my first RF MEMS (cantilever type) in the clean room but I cannot achieve a thick photoresist as the sacrificial layer. I need around 22um thick, but the most I have got is around 10um. does anyone know how can I get that? or any suggestions regarding the type of sacrificial layer that I should use?

Thanks!