We present several characterization techniques, which are suitable for small-size microlenses of lens diameters down to 5 μm. For an individual microlens, we apply full characterization for optical performance and surface characteristics.
First, the optical performance is characterized by using a high-resolution interference microscope (HRIM). Second, a
confocal microscope is applied to investigate the surface parameters. Third, the HRIM allows scanning the microlens
array along the optical axis by using a piezo actuator. This leads to a measurement of the 3D intensity distribution near
the focus of the lens. Such 3D intensity maps allow us to characterize the focal properties of each lens in an array. By
studying those characterization techniques, we develop a new method to characterize a large number of microlenses, for instance, over one million lenses, which is already applied to wafer-based manufacturing in a cleanroom fab.