SIMPLE OPTICAL CHARACTERIZATION METHOD FOR THOUSANDS OF SMALL MICROLENSES FOR INDUSTRIAL MASS-PRODUCTION APPLICATIONS

Myun-Sik Kim, Jonathan Sunarjo, Lisa Allegre, Reinhard Voelkel

Abstract

We present various metrology techniques for small-size microlenses, which can be applied to a single lens or thousands of microlenses. An individual microlens can be characterized by its optical performance and surface profile characteristics. First, the optical performance is characterized by using a high-resolution interference microscope (HRIM), which consists of Mach-Zehnder interferometer and an optical microscope. Second, a confocal microscope is applied to investigate the surface profile parameters. Third, the three-dimensional (3D) intensity distribution near the focus can be measured by the axial scanning function of the HRIM. Such 3D intensity maps allow us to characterize the focal properties of microlenses in an array. By deeply understanding those characterization techniques and measurement outputs, we develop a new method to characterize a large number of microlenses, for instance, more than one million lenses. This method is currently applied to wafer-based manufacturing in a cleanroom fab.

Keywords

micro-optics, microlens array, optical shop test, interferometric characterization, Strehl ratio

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DOI

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IMEKO TC

TC14 - Measurement of Geometrical Quantities

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