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 4.63 microm, a sag height of 1.416 microm, and a residual-layer thickness of 1.15 microm was integrated onto the simulated image sensor. The standard deviations of the sag height and the residual-layer thickness were less than 0.038 microm and less than 0.164 microm, respectively, in whole-wafer-scale samples. The measured beam spot size (FWHM) at the imaging plane was 1.19 microm, with a uniform intensity distribution and pitch in the array.