New fabrication technology for photonic crystal waveguides

We have developed a deep ultraviolet (DUV) lithography technique for fabricating super dense silicon based photonic crystals. Binary mask is used to create nano scale patterns of very high density. Based on the simulation, photonic crystals with both square and triangular lattice of air cylinders are designed and fabricated to work in communication frequency range (λ within 1.3 to 1.55μm) on amorphous silicon. In order to pattern circular hole we designed different kind of polygons on the mask and layout pattern was under sized at constant pitch. Bottom anti reflection coating (BARC) recipe was developed to improve circularity of the pattern and reduce interhole spacing.