Passive alignment microstructures for electroptical devices

Alignment grooves or openings are formed by exposing and developing a photoresist layer formed over a substrate. The edges of the alignment features are rounded by subjecting the photoresist layer to an extended bake at elevated temperature which causes the photoresist to reflow. The rounded edges facilitate the mounting of optoelectronic components such as optical fibres and VCSELs on to the substrate in alignment with the openings or grooves of the photoresist pattern. Alternatively, the photoresist pattern with the rounded edges may be used as a master pattern for a replication mould, and alignment features may be formed by moulding sol-gel or UV curable polymer materials.