Technique Uses Lithography and Etch to Dice Arbitrary Shapes

摘要

How many times have you been standing on the fab floor, looking at M.C. Escher's Sky and Water I woodcut, lamenting to your coworkers how you wish you could cut die to look like those flying duck and fish shapes, instead of boring squares and rectangles? Although your answer may be "Never," researchers have recently done just that - and for more than just artistic reasons. Today's conventional methods of dicing wafers -whether cutting or scribing and breaking - allow for only rectangular die. While rectangles may be perfectly suitable for standard circuit designs, they are not well suited for other types of microfabricated devices, such as arrayed waveguide gratings (AWGs), microfluidic devices or MEMS, all of which are not necessarily rectangular. Because cutting and scribing methods only work with rectangular geometries, these arbitrarily shaped devices must be cut into rectangles, fewer fitting onto a given wafer, and thereby limiting yield. Another limitation with conventional dicing is a minimum die size of ～1 mm. Devices smaller than 1 mm must still be cut into the larger die, again causing yield to suffer.