Mechanical stabilisation and design optimisation of masks for stencil lithography: Numerical approach and experimental validation
This paper addresses mask deformation phenomenon that frequently occurs but is highly undesirable in stencil lithography. Previously, a technique for mechanical stabilisation of stencils was proposed [M.A.F. van den Boogaart, et al., Corrugated membranes for improved pattern definition with micro/nanostencil lithography, Sensors Actuators A 130–131 (2006) 568–574] and successfully validated for simple cantilever-like designs. In present work, the numerical approach to designing optimal geometry of stabilisation structures incorporated onto stencils is applied to complex experimental stencil designs and is validated both numerically and experimentally. Two types of stencil support structures are considered, namely corrugation (hollow rims) and solid silicon rims. Results confirm the effectiveness of the approach and show that up to a 94.5% reduction in stencil deformation with a corresponding improvement in reducing deposited pattern blurring can be achieved. Additionally, design guidelines for the optimal geometries of mechanically stabilised stencils are established. These guidelines can be applied to other types of mechanically unstable structures in need of stiffening to increase their resistance to deformation and improve critical performance characteristics.