A 45° saw-dicing process applied to a glass substrate for wafer-level optical splitter fabrication for optical coherence tomography

Journal article (2016)

Authors

M. J. Maciel University of Minho
C.G. Costa University of Minho
M.F. Silva University of Minho
S.B. Gonçalves University of Minho
A.C. Peixoto University of Minho
A.F Ribeiro University of Minho
R.F. Wolffenbuttel Electronic Instrumentation - EEMCS
J.H.G. Correia University of Minho
Research Group
Electronic Instrumentation (EEMCS) (TU Delft)
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Published Date

22-07-2016

Language

English

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Faculty

Electrical Engineering, Mathematics and Computer Science

Department

Microelectronics

Research Group

Electronic Instrumentation

Abstract

This paper reports on the development of a technology for the wafer-level fabrication of an optical Michelson interferometer, which is an essential component in a micro opto-electromechanical system (MOEMS) for a miniaturized optical coherence tomography (OCT) system. The MOEMS consists on a titanium dioxide/silicon dioxide dielectric beam splitter and chromium/gold micro-mirrors. These optical components are deposited on 45° tilted surfaces to allow the horizontal/vertical separation of the incident beam in the final micro-integrated system. The fabrication process consists of 45° saw dicing of a glass substrate and the subsequent deposition of dielectric multilayers and metal layers. The 45° saw dicing is fully characterized in this paper, which also includes an analysis of the roughness. The optimum process results in surfaces with a roughness of 19.76 nm (rms). The actual saw dicing process for a high-quality final surface results as a compromise between the dicing blade's grit size (#1200) and the cutting speed (0.3 mm s−1). The proposed wafer-level fabrication allows rapid and low-cost processing, high compactness and the possibility of wafer-level alignment/assembly with other optical micro components for OCT integrated imaging.