Development
of thin-film coating process and equipment for heat-resistant resin applicable
to reflow soldering
SHOWA SHINKU has developed a new anti-reflection
coating process and its equipment for the heat-resistant resin lens applicable
to reflow soldering instead of former resins, responding to the transition in
the production of mobile phone camera modules to the reflow soldering process
and wafer-level packaging process. The related patents are pending.
So
far camera lenses are coated by methods such as deposition with an anti-reflection
film, which prevents reflection in the visible spectrum and increases transmittance.
These antireflection films have been indispensable as the camera for a mobile
phone heightens its resolution.
The anti-reflection film on a lens cracks
by stress in a 270 deg C of reflow oven in the former process because of the different
coefficients of thermal expansion between both materials, a heat-resistant resin
and antireflection film. We have developed the coating process and its equipment
for the reflow soldering in addition to the usual environment-resistant performance
necessary for resin lenses.
The manufacturing process of camera modules
for a mobile phone has been shifted from the injection molding with conventional
resin lenses to the reflow soldering and wafer-level packaging with heat-resistant
resin lenses, which are expected to become more widespread.
Why mobile
phone camera modules require the reflow soldering process RoHS restricts
the use of lead in electrical and electronic equipment. As soldering without lead
needs to pass a resin lens through a reflow oven at about 270 deg C higher than
usual, the camera modules for a mobile phone are assembled in a different process
from other modules so far. The high-heat-resistant resin developed by a material
maker has made the reflow soldering process available also to the camera modules
of a mobile phone.
Why mobile phone camera modules require the wafer-level
packaging process The high-heat-resistant resin has made it possible to
pass an assembly through a reflow oven in the same process as other parts. And
in order to further increase the productivity, wafer-level packaging has been
available, which can produce high-heat-resistant resins from hundreds to thousands
of pieces on a wafer while the former injection molding can produce from several
to dozens at once.
