Silicon Microneedle Formation Using Modified Mask Designs Based on Convex Corner Undercut

Inhalt:
In this work we present the mechanism of silicon convex corner undercutting for modified etch masks in aqueous KOH solution (29 % KOH, 79deg C) during rnicroneedle fabrication. Modified mask designs include three different shapes as well as different compensation structures employed to a square mask shape. We have found that square mask-shapes present an optimum structure in contrast to circular or diamond shapes. The use of compensation structures facilitates an increase in needle density of 33 % to 40 %.