SU-8 process for biomedical inspection /spl mu/-carriers

The present study provides a novel carrier fabrication method for biomedical application. The SU-8 thick photoresist fabrication process is used to produce the /spl mu/-carrier of 200 /spl mu/m/spl times/200 /spl mu/m with various thicknesses. These /spl mu/-carriers will be used for the purpose of biomedical inspection after proper surface modification by chemicals. To quantify and qualify the immersed /spl mu/-carriers in the inspected solution, specific marker is designed and fabricated on every /spl mu/-carrier as identification according to the application. Hence, a precise control on the marker feature dimension will be crucial for the application. In addition, the thick resist layer uniformity is very important in defining the marker pattern on the surface of carrier. Besides, the sidewall profile is also crucial especially for the fabrication of 10 /spl mu/m through-hole markers on the carriers of 50 /spl mu/m to 100 /spl mu/m thick. The orthogonal array experimental design method is employed to optimize the process parameters, including the soft bake, exposure, postexposure bake, and development parameters. Moreover, the effect of development with ultrasonic agitation is also investigated.