Method and apparatus for beam deflection in a gas cluster ion beam system

A method of controlling a gas cluster ion beam (GCIB) system for processing a structure on a substrate, the method comprising:

• providing a GCIB system comprising deflection plates that direct a GCIB towards a substrate and a deflection circuit;
• providing a substrate scanning device configured to move the substrate in three dimensions;
• coupling the substrate with the substrate scanning device configured such that a substrate distance between the deflection plates and a surface of the substrate stay within a target range;
• exposing the substrate to the GCIB while the substrate is being moved by the substrate scanning device in one or more dimensions;
• controlling, using a controller, a deflection angle φ of the GCIB incident upon the substrate by controlling a set of deflection operating parameters while the substrate is being exposed to the GCIB in order to achieve one or more deflection objectives.