Dear all, I am using photolithography technique to make a su-8 pattern. The smallest feature width is 10um. The mask shape is a square which side length is 10um. After developing the su-8 pattern sharp features are always lost. The square turns to a circle due to the reflection and diffraction and some optical phenomenon. Does anybody have any ideas about how to solve this problem? Please give me some suggestions... except OPC and PSM. Thanks in advance. Regards