SiON Etch Characteristics Using Low-GWP C 2 F 4 O as a Replacement of CF 4

In semiconductor manufacturing, fluorocarbon gases such as CF 4, CHF 3, C 4 F 8, etc., are widely used in dielectric etching. However, these gases are high global warming potential gases, therefore need to be replaced in the near future. Among these gases, CF 4 is the most difficult gas to be replaced due to its unique and simple structure in addition to its wide range of applications to various semiconductor processing. In this study, with the basic idea of having the same F/(C–O) ratio, trifluoroacetyl fluoride (C 2 F 4 O) was investigated as a potential CF 4 replacement by applying it to PR-masked SiON etching. Using both CF 4 - and C 2 F 4 O-based gases, highly anisotropic SiON hole patterns could be successfully achieved; however, more stable SiON etch characteristics with O 2 flow rate could be achieved with C 2 F 4 O-based gas compared to CF 4 -based gas. In addition, by using C 2 F 4 O-based gas instead of CF 4 -based gas, the reduction of 24–29% in the emission of global warming gases could be achieved. Therefore, by using C 2 F 4 O instead of CF 4, not only process stability in the etching of SiON but also improved environmental effect could be achieved.