Process for the fabrication of microstructures by multilayer conformation of a photosensitive resin et microstructures obtained therewith

摘要

Production of a three-dimensional microstructure involves (a) applying, onto a sacrificial coating (5) on a substrate (4), a 150-700 mu m thick UV sensitive negative photoresist layer (6) consisting of a lacquer containing a multifunctional epoxy composition and a triarylsulphonium salt photo-initiator; (b) heating the layer (6) at 90-95 degrees C for a time depending on its thickness; (c) exposing the layer, through a patterned mask, to UV light at 200-1000 mJ/cm<2> (measured at 365 nm wavelength) depending on the layer thickness; (d) reheating the layer (6) to cause polymerisation; (e) repeating steps (a) to (d), optionally using a different mask (9) for structuring the new photoresist layer (8); (f) developing by dissolution of unexposed photoresist with GBL ( gamma butyrolactone) or PGMEA (propylene glycol methyl ethyl acetate) as solvent; and (g) separating the resulting microstructure from the substrate (4) by dissolution of the sacrificial coating (5). Also claimed is a microstructure obtained by the above process, in which (i) the first photoresist layer is structured in the form of a toothed wheel and the second photoresist layer is structured in the form of a pinion; or (ii) three photoresist layers are structured to obtain a hollow microstructure with two opening on either side of three resistors to form a heat sensor.