University of California

Wen-Hua Chu

Mauro Ferrari

Surface micromachining and bulk micromachining are employed for realizing a porous membrane with bulk support for a microparticle filter. The filter is manufactured by a process employing a thin film etch-stop, in which the bulk substrate is etched using a first etching process followed by etching of the etch stop and of material within pores of a filter layer using a second etching process. The filter is sufficiently sturdy to allow for easy handling. It may be used as a diffusion barrier and under high pressures. The disclosed fabrication method is simple, reliable, and integrated-circuit compatible, and thus amenable to mass production. Electronic circuitry may be integrated on the filter surface, as may be desired for several purposes, such as fluid characterization, filter self-cleaning, or charging of the filter surfaces. Methods are shown for the realization of biological containment capsules based on this microfilter.

Method for forming a filter

A microfabricated containment capsule has a bulk substrate delimiting a cavity with a boundary, a first portion of which constitutes an inner wall of a solid portion of the bulk substrate. The bulk substrate also provides at a second portion of the boundary a membrane joined to one side of the bulk substrate, the membrane having at least one porous area with controlled pores.

Growing community of inventors

Albany, CA, United States of America

Wen-Hua Chu