PDMS to Parylene Adhesion Improvement for Encapsulating an Implantable Device

PDMS to Parylene Adhesion Improvement for Encapsulating an Implantable Device

Bakhshaee Babaroud, N. (TU Delft Bio-Electronics)
Dekker, R. (TU Delft Electronic Components, Technology and Materials)
Serdijn, W.A. (TU Delft Bio-Electronics)
Giagka, Vasiliki (TU Delft Bio-Electronics; Fraunhofer Institute for Reliability and Microintegration IZM)

2020

Parylene-C has been used as a substrate and encapsulation material for many implantable medical devices. However, to ensure the flexibility required in some applications, minimize tissue reaction, and protect parylene from degradation in vivo an additional outmost layer of polydimethylsiloxane (PDMS) is desired. In such a scenario, the adhesion of PDMS to parylene is of critical importance to prevent early failure caused by delamination in the harsh environment of the human body. Towards this goal, we propose a method based on creating chemical covalent bonds using intermediate ceramic layers as adhesion promoters between PDMS and parylene. To evaluate our concept, we prepared three different sets of samples with PDMS on parylene without and with oxygen plasma treatment (the most commonly employed method to increase adhesion), and samples with our proposed ceramic intermediate layers of silicon carbide (SiC) and silicon dioxide (SiO2). The samples were soaked in phosphate-buffered saline (PBS) solution at room temperature and were inspected under an optical microscope. To investigate the adhesion property, cross-cut tape tests and peel tests were performed. The results showed a significant improvement of the adhesion and in-soak long-term performance of our proposed encapsulation stack compared with PDMS on parylene and PDMS on plasmatreated parylene. We aim to use the proposed solution to package bare silicon chips on active implants.

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Proceedings of the 42nd Int. Conf. of the IEEE Engineering in Medicine and Biology (EMBC) 2020

42nd Annual International Conferences of the IEEE Engineering in Medicine and Biology Society in conjunction with the 43rd Annual Conference of the Canadian Medical and Biological Engineering Society, 2020-07-20 → 2020-07-24, Virtual/online event due to COVID-19

Institutional Repository

conference paper

© 2020 N. Bakhshaee Babaroud, R. Dekker, W.A. Serdijn, Vasiliki Giagka