In CMOS image sensor, microlens arrays are generally used as light propagation carrier onto
photo diode to increase collection efficiency and reduce optical cross-talk. Today, the scaling
trend of CMOS technology drives reduction of the pixel size for higher integration density and
resolution improvement.
Microlenses are typically formed by photo resist patterning and thermal reflowing, and the
space between photo resist is necessary to avoid merging of microlenses during thermal reflow
process. With the shrinking sizes, microlenses become more and more difficult to manufacture
without their merging. Hence, the key of light loss free microlens fabrication is still zero-space
between microlenses.
In this paper, we report the selection of the optimum shape of microlens by the dead space
and the curvature of radius. The improvements of critical dimension and thickness uniformities
of microlens are also reported.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.