Oxygen and tetrafluorocarbon magnetically enhanced reactive ion etching (MERIE) of plasma chemical vapor deposited (CVD) boron nitride (BN) and silicon boron nitride (SiBN) was studied for both blanket and submicron patterned films. The relative etch selectivities of the BN and SiBN to oxide (SiO2) and nitride (SiN) were determined. In general, oxygen-rich O-2/CF4 MERIE produce very high etch selectivity results while maintaining vertical etch profiles. This etch process expands the potential for use of BN/SiBN in fabrication of subhalf micron devices.