Abstract: The present invention provides a laser processing and autofocusing system that measures the position of the work-piece at the machining spot, to allow the laser processing of work-pieces which are not flat and have surface variations, with the autofocusing system being able to compensate for these variations. During laser machining, it is desirable to keep the laser focus at the same height with respect to the surface of the sample for the best possible machining quality. Not all samples are flat, though, and it thus becomes necessary to map the surface of the sample accurately and to correct the focusing of the laser beam on the fly. The system includes a processing laser beam directed onto the surface at normal incidence and a light line projected onto the surface in the vicinity of the area being machined but at an angle with respect to the surface normal. The focusing optics for the machining laser and light line generator are fixed relative to each other on a positioning stage.

Abstract: The present invention provides a laser processing and autofocusing system that measures the position of the work-piece at the machining spot, to allow the laser processing of work-pieces which are not flat and have surface variations, with the autofocusing system being able to compensate for these variations. During laser machining, it is desirable to keep the laser focus at the same height with respect to the surface of the sample for the best possible machining quality. Not all samples are flat, though, and it thus becomes necessary to map the surface of the sample accurately and to correct the focusing of the laser beam on the fly. The system includes a processing laser beam directed onto the surface at normal incidence and a light line projected onto the surface in the vicinity of the area being machined but at an angle with respect to the surface normal. The focusing optics for the machining laser and light line generator are fixed relative to each other on a positioning stage.

Abstract: A method of using a laser to cut a groove or pocket of predetermined depth of less than about 0.005 inches in a stencil comprising a polyimide sheet having a thickness in the range of 0.005 to 0.012 inches including the steps of mounting the stencil on a movable work table and positioning and maintaining a laser a predefined distance from the polyimide sheet above the work table. A laser beam is directed against the polyimide sheet to cut an indentation into said polyimide sheet. The laser beam has a pulse duration and a power level to make the cut into the polyimide sheet. The method further includes the step of directing a gas against the polymide sheet where the laser beam cuts into said polyimide sheet. The gas is pressurized. The depth of the indentation cut into the polyimide sheet by the laser is determined by choosing the pressure of the gas relative to choosing the pulse duration and the power level of the laser beam.