Modelling and process capability analysis of Focused Ion Beam

Focused Ion Beam (FIB) machining is a dynamic process whereby atoms can be removed from the surface of a substrate by an accelerated stream of ions, focused into a small area purely by electronic and electrical control. In the fabrication of 3D features such as miniaturised objects, masks and moulds for various microsystems, the control of the depth variation is a critical parameter. A modelling framework integrating computational models for simulation of the FIB milling of predefined shapes, risk analysis, process capability and optimisation that can aid the optimal control of key process parameters is developed and demonstrated. The modelling methodology is based on numerical techniques for discretisation of the FIB process governing equations, statistical analysis, reduced order modelling through response surface approach and non-gradient numerical optimisation.