SU-8 resist is an epoxy-type

near-UV

negative photoresist based on EPON SU-8 resin.The resist has been specifically developed for the applications requiring high aspect ratios in very thick layers. However

this photoresist has proven very sensitive to process variations. The main process variations influencing the pattern such as pre-and postbake temperature and time

exposure time and development time have been studied. And the conclusion that prebake and development time are the main factors affecting the image’s resolution and aspect-ratio

has been drawn.After analyzing the experiment results

a proposed fabrication process for 200μm SU-8 application is given as follows:coating at a speed of 200μm/s

prebaking at 95°C for 1 hour

near-UV（400nm） contacting lithography

postbaking at 95°C for 30 min and development for 20 min. In addition

the main two problems involved in the experiment are researched.One is the bend of substrate

which can be resolved by the following solutions:decreasing the postbake temperature and increasing the postbake time

using thick wafer instead of thin one

dividing the thin wafer into 4～8 pieces and designing the mask reasonably.The other is the removal of SU-8

which can be resolved by the combination of marinating in hot acetone

ultrasonic cleanout

RIE and cineration at high temperature.