Study of Tungsten-Doped Carbon Hard Mask Etch Process Using NF3/O2 Based Chemistry

Tungsten-doped carbon (WDC) materials have been investigated as a hard mask material because of high etching resistance in via and contact holes manufacture integration. This article studied the etching process of WDC in O 2 based plasma with an added reactant source such as Cl 2 or NF 3 chemistry. A series of orthogonal design of experiment (DOE) was utilized to analyze the etch rate data. The results showed that the NF 3 addition can significantly enhance WDC etch rate, compared to Cl 2 addition. The etch selectivity of WDC to silicon oxide (SiO 2 ) mask is increased as using synchronic pulsed RF powers, adding BCl 3 and reducing ESC temperature.