is a semiconductor wafer fabrication process that involves the deposition of the
of the die to
the die from mechanical damage and corrosion. As the name
implies, this final layer is often composed of an
insulating material, or glass.
nitride (Si3N4) is a common glassivating
material because of its suitability for this purpose. Highly
resistant to diffusion, it is almost
to moisture and ionic contaminants such as sodium (Na). It can also be
deposited with a low residual compressive stress, making it less prone
to delamination or cracking. Its interfacing with the underlying
metal layers is also very
Finally, it can be prepared with very low pinhole density.
Since silicon nitride has a high dielectric constant, it is not popular
as an interlayer dielectric for the simple reason that it results
in a high inter-metal capacitance.
can be deposited using plasma-enhanced chemical vapor deposition
or low-pressure chemical vapor deposition
(LPCVD), although the former
is the technique of choice for glassivation purposes because it allows a
lower processing temperature.
Example of an LPCVD system that can be used to
deposit silicon nitride on substrates
Manufacturing; Wafer Fab Equipment
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