Comparison of FTIR and SIFT-MS for the Detection of Climate-relevant Gases in PE-CVD and Plasma Etching Processes in MEMS and Microelectronics Manufacturing

Abstract:
Thin film deposition and plasma etching are essential process steps in semiconductor manufacturing. Typically, technical gases with high GWP (Global Warming Potential) are used, such as SF6, C4F8 or NF3 [1]. With the increasing demand for electronic products, the global production capacity of semiconductor industry is also rising. In this context, considering global climate change, reducing and minimizing CO2 emissions during these processes is of great interest. In this paper, we present measurements on abatement systems connected to a PE-CVD (Plasma-Enhanced Chemical Vapor Deposition) and a plasma etching system using FTIR (Fourier-Transform Infrared Spectroscopy) and SIFT-MS (Selected-Ion Flow-Tube Mass Spectrometry). Based on these measurements, we present DRE (Destruction and Removal Efficiency) calculations for these abatement systems. For thermal wet abatement, a DRE of > 99 % for NF3 is verified using FTIR and SIFT-MS. Also, we show that a dry bed absorber has no significant DRE for SF6 and C4F8, but for HF. Both FTIR and SIFT-MS can measure pre- and post-abatement F-Gas concentrations and are suitable for DRE determination.