Adhesion evaluation of parylene AF4 to silicon and glass substrate

Abstract

This work is focusing on evaluating parylene AF4 adhesion toward silicon and glass substrate. Parylene AF4 with thicknesses of $1.6 {\mu} \mathrm{m}$ and $2.5 {\mu} \mathrm{m}$ was deposited by vapor deposition polymerization (VDP) on a six-inch polished silicon (Si) wafer and glass (SiO2) wafer, thicknesses of $675 {\mu} \mathrm{m}$ and $400 {\mu} \mathrm{m}$ respectively. The adhesion was evaluated using pull-off approach following ISO 15754 standard, where adhesion strength of parylene was measured toward the wafer substrates. For different samples, force vs. time (F/t) curves were measured and compared. Analysis and conclusions regarding the different thicknesses and different substrate materials are made. In addition, optical microscopy was used for analysis and imaging the delamination of the AF4 coatings after the pull-off.