Very high-rate chemical dry etching of Si in F2 remote plasmas with nitrogen-containing additive gases

We investigated the effects of adding N2 and nitric oxide (NO) gases on the chemical dry etching of silicon (Si) in F2 Ar remote plasmas. Additive N2 gas in the F2 Ar N2 remote plasmas enhanced the Si etch rate, while the direct injection of NO gas into the chamber even more markedly increased the Si etch rates. Surface chemical and emission gas analyses indicated that the adsorbed NO molecules on the Si surface enhanced the surface chemical reaction between fluorine and Si atoms, thereby forming SiF4 main etch products and enhancing the etch rate. The NO -induced breaking of the Si-Si bonds was considered to facilitate the SiF4 formation.