Solvent Compatibility of Parylene C Film Layer


Koydemir H. C. , KÜLAH H. , ÖZGEN C.

JOURNAL OF MICROELECTROMECHANICAL SYSTEMS, vol.23, no.2, pp.298-307, 2014 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 23 Issue: 2
  • Publication Date: 2014
  • Doi Number: 10.1109/jmems.2013.2273032
  • Title of Journal : JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
  • Page Numbers: pp.298-307

Abstract

Parylene C has been preferred in various microfluidic and packaging applications as a chemical barrier; therefore, its durability in chemicals is critical to maintain functionality of the devices. In this paper, we investigated solvent compatibility of Parylene C in a range of solvents with regard to swelling of it and the change in its surface roughness at room temperature. The results of Parylene C swelling were associated with solubility parameter, delta (cal/cm(3))(1/2), which is predicted from the parameters of dispersion, polar, and hydrogen-bonding forces. Solvents that swelled Parylene C film layer mostly were benzene, chloroform, trichloroethylene, and toluene, while methanol, 2-propanol, ethylene glycol, and water did not cause any swelling. Subsequently, the adverse effects of diffusion of solvents through a Parylene C film layer were demonstrated by stripping of the encapsulated photoresist. In addition, a comparison was made between Parylene C and poly(dimethyl) siloxane (PDMS) considering the data of swelling ratios obtained from the experimental findings and the literature, respectively. Experimental findings showed that Parylene C is much more compatible to solvents than PDMS in high-throughput microfluidic and packaging applications. These results will be of great value to scientists for understanding compatibility of any selected solvent on Parylene C in the applications of micro devices. [2013-0113]