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 NOx production can be reduced through optimizing the amount of O2 supply.

In semiconductor manufacturing, greenhouse gases, such as perfluorocarbons (PFCs) and nitrogen trifluoride (NF3), which are sources of global warming, are frequently used to remove substances during cleaning and etching. Particularly, NF3, which has a high global warming potential (GWP) is widely used for chamber cleaning in the chemical vapor deposition (CVD) process. There is an urgent need to replace high GWP gases with eco-friendly gases. In this study, we investigated the possibility of replacing NF3 with N2 gas from the existing NF3/O2 gas mixture during the cleaning process in a plasma-enhanced CVD (PECVD) chamber for the formation of an amorphous carbon layer. The kinetic reaction mechanism of nitrogen-augmented plasma was investigated using ANSYS Chemkin-Pro, and the verification was conducted using an environmentally friendly gas-based direct plasma cleaning process in the PECVD chamber with capacitively coupled plasma (CCP). The verification experiment was conducted with a 150-mm laboratory scale and a 300-mm production equipment. Chemical reaction analysis was then performed to analyze the chemical reaction mechanism in the plasma and identify the trends in the cleaning efficiency. The results derived from the analytical and empirical experiments showed that the addition of N2 positively affected the reaction of O2 in the plasma with surface materials; this improved the cleaning, and the effectiveness of eco-friendly cleaning processes using alternative gases could be confirmed.