MODELING AND MEASUREMENT OF MELTED MICROLENS SHAPES

A heuristic approach to the formation of reflow photoresist lenses is described. The approach is a polynomial one using simple assumptions f or the boundary conditions of the lenses. Already a fourth order appro ach can explain why central dips occur and for which parameters such d ips are probable. With the measurement of the central sagitta of the l enses one may also use a sixth order approach which explains even more complex shapes. For the measurement of the lens shape a Mach-Zehnder and a Linnik interference microscope have been used. The first experim ental results seem to support the results obtained with the heuristic approach. Finally an iterative approach to extract the surface profile from reflection (Linnik) and transmission (Mach-Zehnder) interferomet ric measurements is presented.