The ion beam etching (IBE) is a physical dry etch process.

Thereby argon ions are radiated onto the surface as an ion beam with about 1 to 3 keV. Because of the energy of the ions, they strike out material of the surface.

The wafer is held perpendicular or tilted into the ion beam, the etch progress is absolute anisotropic.

The selectivity is low because there is no differentiation of the individual layers.

The gas and the strike out material are exhausted by vacuum pumps, however, particles can deposit on the wafer or on chamber walls since the reaction products are not in gaseous state.

To avoid particles a second gas is led into the chamber. This gas reacts with the argon ions and causes a physical chemical etch process.

Partially the gas reacts with the surface but also with the strike out particles to form gaseous byproducts.

Almost every material can be etched with this method. Due to the perpendicular radiation the abrasion on vertical walls is very low (high anisotropism).

However, because of the low selectivity and the low etch rate, this process is only used rare in todays’ semiconductor fabrication.