The use of reactive ion etching (RIE ) with fluorinated gas plasmas, such as SF6, CF4, CBrF3, and CHF3mixed with oxygen, to achieve selective patterning of tungsten films is reported. The etch rates of W, Si, and SiO2were measured as a function of oxygen percentage in fluorinated gas plasmas under various conditions. Experiments on selectivity indicate that a CHF3/70%O2mixture under 20 sccm, 200 W, 20 mTorr etching conditions results in W:Si and W:SiO2etch rate ratios of 1.6:1 and 1.8:1, respectively. Optimized W:Si and W:SiO2selectivity ratios 4:1 and 4.8:1 have been obtained at 60 mTorr/150 W and 260 mTorr/200 W plasma conditions. For reverse selectivity, the optimum W:SiO2etch rate ratio measured is 1:4.6 in pure CHF3gas. The optimum W:Si reverse selectivity of 1:11.6 is obtained with an SF6/5%O2mixture plasma. A vertical‐to‐lateral etch ratio of 4:1 was measured with CHF3/70%O2, 200 W, 10 mTorr, 20 sccm. The etching mechanisms of tungsten due to chemical and physical processes in various fluorocarbon gases under the RIE mode have been investigated and the role of etching species such as fluorine, bromine, and oxygen is discussed.