Hi, All, I expose a thick SU-8 2100 layer with a 320nm laser. After postbake, I found out the layer is curved up. The picture is shown in the link below. http://base.google.com/base/items?oid=15423750006658009412 We used a broadband UV before for exposure and we never have the problem like this with the same layer of SU-8. Any suggestion would be appreciated. Thank you. Richard