Conformable Deposition of Biocompatible Parylene‐C Coatings for High Aspect Ratio,  including LIGA,  Microstructures

Presently, the research in the area of miniaturized devices drives the interest of developing a functional coating that can be pin hole free and conformably deposited on varying high aspect ratio (HAR) microstructures [1-6]. Research on parylene at CAMD is addressing the issues and requirements of biocompatible and/or surface functional coatings for HAR including multilevel X-ray fabricated microstructures as well as microfluidic chips. Conformal, functional coatings of complex, multi-material chips manufactured by state-of-the-art MEMS techniques will be crucial for future applications demanding low fabrication costs. Parylene, a polymeric coating deposited at room temperature, possesses excellent pin hole free, conformable deposition, mechanical strength, stress-free, chemically inert and barrier properties [7-8]. In the present study Parylene-C deposited on polymeric and metallic substrates was characterized by scanning electron microscopy (SEM) and optical profilometry. Parylene-C was conformably deposited on various microfluidic structures with aspect ratios ranging from 1 to>10 using a parylene coater (Paratronix, Inc. Model 494). The surface morphology, conformability and the pin-hole free deposition of the parylene coatings wa