A method of reducing foreign material contamination of a substrate in an ion beam system and an ion beam system. The system, including: a vacuum chamber having an ion beam axis; a substrate chamber free to tilt about a tilt axis, the tilt axis orthogonal to and intersecting the ion beam axis; a flexible bellows connecting an opening in the substrate chamber and an opening in the vacuum chamber, both openings co-axially aligned with the ion beam axis, the bellows providing a vacuum seal between the substrate chamber and the vacuum chamber; and a hollow foreign material shield open at a top proximate to the vacuum chamber and a bottom proximate to the substrate chamber, the foreign material shield located between the ion beam axis and the flexible bellows, the top and bottom of the foreign material shield co-axially aligned with the ion beam axis.