Patent ID: 8354033

Claim:
A method for producing porous microneedles situated in an array on a silicon substrate, comprising: providing a silicon substrate; applying a first etching mask on the silicon substrate; patterning microneedles using a deep reactive ion etching (DRIE) process; removing the first etching mask; and porosifying the silicon substrate to a limited extent to form a first porosified layer adjacent to a second, non-porosified layer which remains in the silicon substrate; wherein: the porosification begins on a front side of the silicon substrate and forms a porous reservoir; during the patterning of the microneedles, an inner passage is etched into each microneedle; and the first porosified layer is transformed, by an isotropic etching process in the second, non-porosified layer, into a state that is accessible from a back side of the silicon substrate.