Development of an ultraviolet imprinting process for integrating a microlens array onto an image sensor

We analyzed the feasibility of using a UV imprinting process to integrate a microlens array onto an image sensor. A simulated wafer-scale image sensor chip array was fabricated for the implementation. A microlens array with a side length of 4.63μm, a sag height of 1.416μm, and a residual-layer thickness of 1.15μm was integrated onto the simulated image sensor. The standard deviations of the sag height and the residuallayer thickness were less than 0.038μm and less than 0.164μm, respectively, in whole-wafer-scale samples. The measured beam spot size (FWHM) at the imaging plane was 1.19μm, with a uniform intensity distribution and pitch in the array.