Fabrication of cantilever chip with complementary micro channel system in SU-8 for biochemical detection

Abstract: This thesis presents the works on fabrication and measurements done with micro cantilevers and a micro channel system, fabricated in the photo-resist SU-8. SU-8 is a polymer patterned by UV lithography which offers a cheap and fast processing and is an interesting alternative to standard Si techniques. For the structures intended here, it proved to be a well suited material and promising results were obtained. The project involved the design of one cantilever chip with arrays of cantilevers structured into three sections of five cantilevers each and one micro channel chip, which were batch fabricated. The cantilevers are used for biochemical detection by surface stress measurements with optical read-out. Together, the two chips can be used for specific molecular detection for research oriented or medical purposes. The cantilevers proved to be very sensitive and DNA immobilisation detection was achieved. The channels are an essential component in this system for easy handling of the solutions to be investigated and sensitising of the cantilevers prior to the measurements. To achieve the above results, several experiments were performed, investigating the surface properties of SU-8. Little has until this point been known about the surface properties of the the photo-resist and several key pieces of information were obtained, which proved to be crucial in the project. Here, the work involved in the design and fabrication of both chips is described in detail. Also, the work on the surface investigations is presented and indications of necessary further work is given. A brief description of the measurements done is also included in the Thesis.