Scandium aluminum nitride (ScAlN)
demonstrates notable properties such as high electromechanical coupling,
low dielectric permittivity, reduced acoustic losses, and so on. Yet,
ScAlN-based device fabrication is challenging, especially controlling
the etching process at higher scandium concentrations. This study
optimizes the etch recipe by precisely controlling the ScAlN etch
rate and sidewall angle using an inductively coupled plasma (ICP)
system, characterizing the results with scanning electron microscopy
(SEM). We acknowledged that the etch gas flow rates, ICP/RF power,
and chamber pressure critically influence the ScAlN etch rate and
sidewall angle. Implementing a machine learning (ML) regression model,
we predicted these etching outcomes as a function of etch parameters
based on historical data correlations, accounting for complex underlying
etching physics. We validated the ML model using an independent data
set, and it demonstrated over 95% accuracy in predicting ScAlN etch
characteristics. This approach significantly enhances the understanding
of ScAlN etching, proving ML’s efficiency in etch recipe optimization,
which is essential for fabrication of advanced ScAlN-based devices
in optoelectronics and RF applications.