Idil, Ahmad Shah;
Bailey, Richard;
Escobedo-Cousin, Enrique;
Gausden, Johannes;
O'Neill, Antony;
Donaldson, Nick;
(2024)
Voiding in Parylene-C Encapsulation of Surface
Mount LEDs for an Optogenetic Epilepsy Neuroprosthesis.
In:
2023 24th European Microelectronics and Packaging Conference & Exhibition (EMPC).
(pp. pp. 1-5).
IEEE: Cambridge, United Kingdom.
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Abstract
It is often assumed that Parylene-C encapsulation films are void-free & conformal by nature of their vapour deposition. We present a case study in an optrode device where voiding occurs; we argue the voids originate from the geometry of the substrate and from the use of surface mount components. The segment under study consists of a commercial LED bonded with Au/Au thermosonic bonding onto a custom silicon substrate. We demonstrate via micro-sectioning that there is polymer voiding behaviour (1) in sub-LED surfaces; and (2) within through-hole vias in the silicon substrate (channels designed to allow polymer vapour ingress during deposition). By making a comparison to the solutions found in the IC industry around tungsten vapour filling of blind vias, we present geometric solutions for failure mitigation.
| Type: | Proceedings paper |
|---|---|
| Title: | Voiding in Parylene-C Encapsulation of Surface Mount LEDs for an Optogenetic Epilepsy Neuroprosthesis |
| Event: | 24th European Microelectronics and Packaging Conference (EMPC2023) |
| Dates: | 11 Sep 2023 - 14 Sep 2023 |
| ISBN-13: | 978-0-9568086-9-1 |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.23919/EMPC55870.2023.10418444 |
| Publisher version: | https://doi.org/10.23919/empc55870.2023.10418444 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Optrodes, neuroprostheses, Parylene-C, voids, encapsulation, micropackaging |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Med Phys and Biomedical Eng |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10209352 |
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