Abstract: High speed removal of material from a specimen employs a beam positioner for directing a laser beam axis along various circular and spiral laser tool patterns. A preferred method of material removal entails causing relative movement between the axis of the beam and the specimen, directing the beam axis at an entry segment acceleration and along an entry trajectory to an entry position within the specimen at which laser beam pulse emissions are initiated, moving the beam axis at a circular perimeter acceleration within the specimen to remove material along a circular segment of the specimen, and setting the entry segment acceleration to less than twice the circular perimeter acceleration.

Abstract: Laser pulse energy adjustments are motivated by an understanding of the effect of laser pulse width variations among different lasers on satisfying a quality metric associated with a laser-processed target. In a preferred embodiment, the adjustments normalize this effect among different lasers drilling vias in a target specimen. The number of pulses delivered to the target specimen to form each via can be modified, based on the pulse energy applied to the via location, to control different via quality metrics.

Abstract: A differential diameter hole drilling method by which through-holes having improved major surface quality are formed in a target material involves drilling a pilot hole having a diameter that is less than the desired diameter of the through-hole and then drilling a through-hole having the desired diameter. The pilot hole forms a channel from which thermal energy produced during laser drilling can diffuse into the environment, thereby reducing the amount of thermal energy diffusing into the surrounding target material matrix and the degree of thermal damage to the heat affected zone of the target material matrix. The pilot hole also forms a channel through which ablated target material may be removed, thereby increasing overall through-hole throughput. Pilot hole formation reduces the thermal energy required to form the remaining portion of the through-hole and thereby results in less thermal damage to the surrounding target material matrix.