Fabrication of Precise Die Edges for Micro-Optical and MEMS Applications

A method for fabricating precise silicon die edges aligned to a precision of 0.5 mum to the features on the front side of the die without damaging these features is described in this paper. A two step die edge fabrication process with die edge defined by silicon DRIE on the front side of the die and edge grinding on the backside of the die was developed. The features on the front-side of the die close to the edge are not mechanically damaged by this technique. Test structure design and fabrication to measure the precision of die edge with respect to the features on the front side is discussed. Die cleaning process using a protective coating deposited prior to the sawing and grinding processes is also presented.