Patent attributes
Light guiding structures are provided to improve the light coupling between photonic active devices and the top of a metallization layer stack interconnecting these photonic active devices. Each light guiding structure comprises a hole extending between the near surface of the photonic active devices and the top surface of the metallization layer stack, said hole being filled with dielectrics or a combination of dielectrics and metals. Such a light guiding structure removes from the optical path of light rays, the interfaces between the metallization layers, thereby confining light laterally and enabling interconnects with increased thickness and more levels of metal. This results in the suppression of multiple reflections and optical crosstalk. The light guiding structures can have cross-section diagonals with sub-wavelength dimensions can be fabricated after all CMOS process steps, thus having minimal interference and maximal compatibility with CMOS processing.
