Plasma polymer process for microfluidic devices fabrication

Summary form only given. Plasma polymerization, so called remote plasma enhanced chemical vapour deposition (RPECVD) has been increasingly used in microsystems field. Plasma polymers served primarily as supports for electronic sensors or carriers for biomolecules and cell attachment. This work describes the first use of plasma thin film deposition for the easy, fast and reduced cost fabrication of microfluidic channels. A new method named "plasma polymerization on a micropatterned surface" (PPMS) is presented. First, micropatterns representing the desired channels were designed on a silicon wafer, either by lithography of a sacrificial photoresist or by plasma etching of the Si substrate. Then, the patterned substrate was introduced into the reaction chamber of a home-made microwave (2.45 GHz) plasma reactor. The organosilicon monomer 1,1,3,3,tetramethyldisiloxane was used as the precursor to synthetize and deposit a polymer organosilicon film by a remote afterglow PECVD. The deposited polymer is used as the structural material of the microfluidic network. Unlike conventional plasma deposition methods, PPMS process occurs at moderate temperatures and allows the deposition of a wide range of thicknesses (10 nm-500 mum), with 14 nm/s growth rate. Our method enables a rapid creation of capillarity-driven flow systems with channels width ranging from 4 to 700 mum without pillars. Channels are characterized and successfully tested. Capillary forces draw water, as well as aqueous solution into the channel from the inlet reservoir to the outlet one with the initial velocity of 4.4 cm/s. In addition, PPMS easily and softly allows the building of transparent microfluidic networks directly on processed electronic components.