Method and apparatus for addressing thickness variations of a trench floor formed in a semiconductor substrate

摘要

A method for utilizing interference fringe patterns generated when milling a trench through a semiconductor substrate by a method such as FIB milling, to determine and optimize the thickness uniformity of the trench bottom. The interference fringes may be mapped and the mapping used to direct the FIB milling to those regions which are thicker to correct observed non-uniformities in the trench floor thickness by varying the pixel dwell time across the milled area. The interference fringe mapping may be used to develop computerized contour lines to automate the pixel dwell time variations as described above, for correcting non-uniformities in the trench floor thickness. The method may be applied to applications other than trench formation for backside editing, such as monitoring progress in forming a milled object.