EPP Europe P2.2022

AT A GLANCE
In this article, Koh Young
details the importance of
accurate CCI and
measurement, and explains
how its new 3D in-line DPI
equipment can conduct
2D and 3D inspection of
transparent materials.
Conformal coatings protect electronics
from moisture, debris, and corrosion.
They also add mechanical stability to
help reduce failures and improve an
electronic device’s reliability when it is
exposed to harsh environments. But
what happens if a coating is defective
or simply too thin? Koh Young discusses
the challenges of conformal coating
inspection (CCI) and how its latest
Neptune series can help.
A
conformal coating is a transparent protective
film with a thickness of around 50um applied
to a PCB to protect the board and its components
from corrosion (caused by vibration, temperature
changes, and so on) and from the environment. It is
used on parts that need to offer increased product
reliability via dustproofing and waterproofing. As
conformal coatings significantly reduce the chance
of circuit failure due to moisture, they are now being
increasingly applied to products which necessitate a
high level of reliability. There are various coating
methods used today including dipping, brushing, and
spraying. Selective spraying methods that only coat a
specific area are also being more widely used.
In addition to conformal coatings, various other
dispensing technologies such as underfill and overcoating
are emerging in the market. Underfill redistributes
the thermomechanical stress created by
the coefficient of thermal expansion mismatch between
the silicon chip and organic substrate and is
often applied to BGAs and CSPs in semiconductors
or during SMT processes. In some medical applications,
a droplet-shaped coating needs to be
placed on the pad, in a process known as overcoating,
and the height of this droplet needs to be
measured. Indeed, as this example makes clear,
some dispensing applications now also require specific
inspection processes.
EPP Europe » 11 | 2022 17