Improved process flow for buried channel fabrication in silicon
The fabrication of microchannels using MEMS technology always attracted the attention of researchers and designers of microfluidic systems. Our group focused on realizing buried fluidic channels in silicon substrates involving deep reactive ion etching. To meet the demands of today’s complex microsystems, our aim was to create passive microfluidics in the bulk Si substrate well below the surface, while retaining planarity of the wafer. Therefore additional lithographic steps for e.g. integrating circuit elements are still possible on the chip surface. In this paper, a more economic process flow is applied which also contains a selective edge-masking method in order to eliminate under-etching phenomenon at the top of the trenches to be filled. The effect of Al protection on the subsequent etch steps is also discussed. Applying the proposed protection method, our group successfully fabricated sealed microchannels with excellent surface planarity above the filled trenches. Due to the concept, the integration of the technology in hollow silicon microprobes fabrication is now available.
- Ganji B A and Majlis B Y (2006) Deep trenches in silicon structure using DRIE method with aluminum as an etching mask. In: IEEE interernational conference on semiconductor electronics pp 41–47Google Scholar
- Gao F, Ylinen S, M. Kainlauri M and Kapulainen M (2011) A modified Bosch process for smooth sidewall etching. In: Proceedings of 22nd micromechanics and microsystems technology Europe workshop, Paper A12Google Scholar
- Park S, Jang Y, Kim H C and Chun K (2008) Fabrication of drug delivery system with piezoelectric micropump for neural probe. In: Proceedings of 23rd International Technical Conference on Circuits/Systems, Computers and Communications 2008, Yamaguchi, Japan pp 1149–1152Google Scholar
- Rusu C, van’t Oever R, de Boer MJ, Jansen HV, Berenschot JW, Bennink ML, Kanger JS, de Grooth BG, Elwenspoek M, Greve J, Brugger J, van den Berg A (2001) Direct integration of micromachined pipettes in a flow channel for single DNA molecule study by optical tweezers. J Microelectromech Syst 10:238–245CrossRefGoogle Scholar