New wafer-scale fabrication method for stacked optical waveguide interconnects and 3D micro-optic structures using photoresponsive (inorganic-organic hybrid) polymers

The rapid growing demands on the number of data transport channels in integrated optical circuits are hitting the border of the integration density, which is realizable with the currently used planar technologies due to the limited wafer size. An approach to overcome this problem by the stacking of optical single-mode waveguides is presented. This newly developed technology is based on successive UV photolithography using the material system of hybrid inorganic-organic polymers (ORMOCER(R)s). To ensure a perfect structure homogeneity over the whole stack, a detailed theoretical and experimental investigation of the UV patterning process concerning the non-linear response of the material to the exposure light is done. The applicability of the newly developed wafer-scale fabrication method is presented by the exemplary realization of a four layer stack. Following this method of an UV induced local curing, the potential of a controlled photopolymerization for the realization of complex 3D micro-optical structures is presented on the basis of first experimental results. (C) 2002 Published by Elsevier Science B.V.