Ion orbits in electron shading damage

Abstract

In Hashimoto's' hypothetical mechanism for electron shading damage, the photoresist at the tops of trenches and vias collects a negative charge from the thermal electrons, creating an electric field (E-field) which prevents electrons from reaching the trench bottom, where a "collector" is located. The ions, accelerated by the sheath electric field, are driven straight into the trench and impinge on the collector, charging it positive if it is isolated. The electric fields inside the trench can also deflect the ions into the sidewalls, causing notching and other deformations of the etch profile The present effort aims to test the hypothesis by scaling the submicron features to macroscopic size so that the currents and potentials inside the trench can be measured and compared with computations. This paper concerns the theoretical part of the work; namely, self-consistent computations of the E-fields and ion orbits inside the trenches.