Quantitative Evaluation of Photoresist Patterns in the 1-μm Range

During exposure of photoresist layers the light distribution inside the resist is essentially determined by three factors: the incident light pattern generated by the exposure system at the resist surface; the absorption of light by the photoresist; and the reflected waves at the interfaces between layers. Due to standing wave effects, regions of different light intensity are created inside the resist, leading to steplike edge contours of the photoresist after development. The shape of photoresist patterns can be calculated.