NF 3 Gas Reduction and Cleaning-Efficiency Improvement through RPG Waveguide Diameter Optimization in PECVD Process Equipment

Owing to the advancement and miniaturization of three-dimensional NAND semiconductor processes, the demand for NF₃ gas used in PECVD chamber cleaning has increased significantly. However, supply shortages and high material costs have increased process expenses. This study presents a method for improving the radical transfer efficiency of fluorine and reducing NF₃ gas consumption by optimizing the remote plasma generator waveguide diameter from the conventional ∅40 mm to ∅25 and ∅16 mm. Based on Bernoulli's principle and the Venturi effect, we analyzed the fluid dynamics inside the waveguide and quantitatively evaluated the changes in cleaning efficiency as a function of waveguide diameter through real-time monitoring using a residual gas analyzer and wafer etch rate measurements. Experimental results show that changing the waveguide diameter to ∅25 mm improved the etch rate by 35% on average, whereas adopting a Venturi adapter combined with a temperature -control module afforded an additional 15% improvement in efficiency, thus resulting in a total NF₃ gas reduction of up to 50%. This study proposes practical solutions that can contribute to cost reduction and reduced environmental impact in semiconductor-manufacturing processes.