Microfiltration membrane sieve with silicon micromachining for industrial and biomedical applications

With the use of silicon micromachining an inorganic membrane sieve for microfiltration is constructed, having a siliconnitride membrane layer with thickness typically 1 pm and perforations typically between 0.5 pm and 10 pm in diameter. As a support a <lOO>-silicon wafer with openings of loo0 pm in diameter is used. The thin siliconnitride layer is deposited on an initial dense support by means of a suitable Chemical Vapour Deposition method (LPCVD). Perforations in the membrane layer are obtained through the use of standard microlithography and reactive ion etching (RIE). The flow rate behaviour and the pressure strength of the membrane sieve are calculated in a first approximation. A process for manufacturing is presented and some industrial and biomedical applications are discussed.