Patent ID: 8048774

Claim:
A method of machining a substrate comprising the steps of: (a) using a laser emitting visible or ultraviolet radiation to machine a formation in a first surface of the substrate to a predetermined depth from the first surface that is less than a full depth of the substrate; and (b) subsequently removing material from a second surface of the substrate opposed to the first surface to the predetermined depth from the first surface to communicate with the formation using one of: chemical etching; plasma etching; and laser ablation, wherein step (a) is performed in a non-ambient controlled gas environment, using at least one of a reactive gas and a passive gas at least one of prior to, during and after laser machining, wherein using the passive gas comprises using a passive gas substantially inert with respect to the substrate substantially to prevent oxidation of the substrate during laser machining thereof, and wherein using the reactive gas comprises using gas reactive with respect to the substrate to reduce roughness of laser-machined surfaces formed in step (a) or to remove debris created in step (a).