Patent ID: 8344285

Claim:
An apparatus enabling a laser to ablate a region of a substrate, the apparatus comprising: a partially closed debris extraction module ( 4 ) located between a focussing or imaging lens ( 2 ) for a laser beam ( 3 ) and a region of a substrate ( 1 ), the debris extraction module ( 4 ) having input ( 8 ) and output ( 6 ) ports by which a flow of a fluid is caused to flow over the region of the substrate ( 1 ) so as to entrap debris ablated from the region and thereafter to remove the entrapped debris from the region of the substrate ( 1 ) by providing for the flow of fluid, with entrapped debris, to pass away from the region of the substrate ( 1 ) along a predetermined path which prevents subsequent deposition of entrapped debris on the substrate, and wherein the flow of fluid is caused to flow in a closed loop, the debris extraction module ( 4 ′) is attached to an air puck ( 9 ) that floats on the substrate ( 1 ), a plurality of ports being located on at least two sides of the air puck, and the plurality of ports being arranged for directing a flow radially inward, from an outside of the puck to an inside of the puck, toward the region of the substrate ( 1 ), and the fluid, on extraction from the debris extraction module, is re-circulated and returned to the debris extraction module in a closed loop via a pump and a filter.