The effect of processing conditions on the curvature of SU-8 cantilevers up to 6400 νm long is determined by experimental methods. Our observations suggest that a zero curvature condition can be achieved by controlling the exposure dose and post-exposure baking time for any given SU-8 thickness. The curvature of SU-8 cantilevers processed with different exposure doses and post-exposure baking times has been measured and reveals that the gradient of crosslinking density throughout the SU-8 film is the cause of out-of-plane stress. A general model for the SU-8 cantilever curvature is developed which explains the behavior of SU-8 structures that have been processed with different conditions and can be used to predict the general effect on the SU-8 cantilever curvature for different SU-8 thicknesses and process parameters.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Mechanics of Materials
- Mechanical Engineering
- Electrical and Electronic Engineering