Fabrication of a three-layer SU-8 mould with inverted T-shaped cavities based on a sacrificial photoresist layer technique

• Published in: Biomedical microdevices 2014-10, Vol.16 (5), p.655-660
• Main Authors: Liu, Junshan, Zhang, Dong, Sha, Baoyong, Yin, Penghe, Xu, Zheng, Liu, Chong, Wang, Liding, Xu, Feng, Wang, Lin
• Format: Article
• Language: English
• Subjects: Biological and Medical Physics; Biomedical engineering; Biomedical Engineering and Bioengineering; Biomedical materials; Biophysics; Cell Line; Dimethylpolysiloxanes - chemistry; Engineering; Engineering Fluid Dynamics; Epoxy coatings; Humans; Nanotechnology; Nylons - chemistry; Tissue Array Analysis - instrumentation
• ISSN: 1387-2176; 1572-8781
• DOI: 10.1007/s10544-014-9868-y

A novel method for fabricating a three-layer SU-8 mould with inverted T-shaped cavities is presented. The first two SU-8 layers were spin coated and exposed separately, and simultaneously developed to fabricate the bottom and the horizontal part of the inverted T-shaped cavity. Then, a positive photoresist was filled into the cavity, and a wet lapping process was performed to remove the excess photoresist and make a temporary substrate. The third SU-8 layer was spin coated on the temporary substrate to make the vertical part of the inverted T-shaped cavity. The sacrificial photoresist layer can prevent the first two SU-8 layers from being secondly exposed, and make a temporary substrate for the third SU-8 layer at the same time. Moreover, the photoresist can be easily removed with the development of the third SU-8 layer. A polydimethylsiloxane (PDMS) microchip with arrays of T-shaped cantilevers for studying the mechanics of cells was fabricated by using the SU-8 mould.