Fabrication of microchannels using polycarbonates as sacrificial materials

The use of polycarbonates as thermally decomposable, sacrificial materials for the formation of microchannels is presented. Pol, carbonates decompose in the temperature range of 200-300 degreesC. Two polycarbonates, polyethyl ene carbonate and polypropylene carbonate, have been used to fabricate micr ochannels in three different types of encapsulants: an inorganic glass (sil icon dioxide), a thermoplastic polymer (Avatrel dielectric polymer) and a t hermoset polymer (bisbenzoycyclobutene Cyclotene 3022-57). This paper prese nts the details of the fabrication process, a thermogravimetric analysis of the sacrificial materials, and the kinetic parameters for the decompositio n process. The presence of oxygen or water was found to impact on the decom position of the sacrificial material. This paper demonstrates the feasibili ty of forming buried air-cavities in a variety of encapsulants at a modest temperature, thus enabling the use of a wide range of dielectric materials with different thermal stabilities and properties.