In-situ laser redeposition reduction by a controlled gas flow and a system for reducing contamination

A processing apparatus, comprising:

• a vacuum chamber;
• a laser optical system that includes an objective situated within the vacuum chamber and operable to direct an optical processing beam to a workpiece to remove material from the workpiece;
• a charged-particle-beam (CPB) optical system situated to direct a charged particle beam to the workpiece;
• and
• a process controller coupled to the vacuum chamber to introduce a background gas to inhibit deposition of workpiece material on the laser optical system during processing with the laser optical system.

A system for ion beam and laser beam milling of a workpiece retained in a vacuum chamber, comprising:

• a laser optical system that includes an optical surface facing a workpiece area;
• a background gas source operable to introduce a background gas into the vacuum chamber to establish a pressure suitable to reduce laser ablation debris deposition on the optical surface facing the workpiece, wherein the laser optical system is operable to ablate the workpiece within the vacuum chamber at the established pressure;
• an ion beam system operable to mill the workpiece with an ion beam;
• and
• a process controller coupled to the laser optical system, the background gas source, and the ion beam system and configured to select laser ablation with the laser optical system with the background gas in the vacuum chamber and ion beam milling with the ion beam from the ion beam system after evacuating the background gas from the vacuum chamber.