Chemical reaction mechanism of plasma scrubber for by-product treatment in TiN-atomic layer deposition processes

Abstract

In atomic layer deposition (ALD), unreacted precursors released from the process chamber can cause agglomeration of powders inside the fore line, exhaust line, and dry pump. Thus, it shortens the preventive maintenance cycle of dry pumps in a high-volume manufacturing environment. A plasma pretreatment system (PPS) is designed to facilitate formation of by-product powders prior to entering the mechanical pumps in ALD systems. In this paper, we present the optimal operating conditions of a PPS for achieving an optimal TiO2 substitution rate with a TiCl4 precursor. To expedite the chemical reactions of unreacted precursors with oxygen, we studied reaction simulation and computational fluid dynamics to optimize the flow of oxygen in the PPS. The results established the basis for the gas flow conditions of actual processes. Gas waste and NO x production can be reduced through optimizing the amount of O2 supply.