The AJA International ATC 1500-F ion mill system has a 250 mm diameter ion source. The system  can process substrates up to 150 mm in diameter with reasonable uniformity.   The system is supplied with two mass flow controllers (MFC) to allow the introduction of two gasses into the process chamber.

Ion beam etching, or milling, is a technique conceptually similar to sandblasting, but uses individual atoms in an ion beam to erode the material. A photolithographic patterned wafer is placed in the vacuum chamber and exposed to the ion beam. The impact of the ions erodes the exposed thin film, not covered by the photoresist.  This technique is especially beneficial for selectively removing thin film materials that cannot be etched using conventional plasma etch techniques such as Pt, Pd, Au, etc.