Laser machining system and method
AssigneeElectro Scientific Industries, Inc.
InventorsAdrian Boyle, Oonagh Meighan, Gillian Walsh, Kia Woon Mah
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Abstract
A substrate (16) is machined to form, for example, a via. The substrate is in a chamber (15) within which the gaseous environment is controlled. The machining laser beam (13) is delivered with control of parameters such as pulsing parameters to achieve desired effects. The gaseous environment may be controlled to control integral development of an insulating lining for a via, thereby avoiding the need for downstream etching and oxide growth steps. Also, machining may be performed in multiple passes in order to minimize thermal damage and to achieve other desired effects such as a particular via geometry.
Claims53
A laser machining method comprising the steps of:
- providing a gaseous environment around a machining site on a substrate comprising a semiconductor;
- delivering a pulsed laser beam to the machining site to machine the substrate to form a via at the machining site,
- wherein at least one of laser-pulse energy and laser-pulse separation of the laser beam are varied during machining of the substrate according to optical, thermal and mechanical properties of the substrate being machined and oxygen or nitrogen concentration in the gaseous environment is controlled during machining of the substrate to control growth of a via lining, and
- wherein the gaseous environment comprises a gas having properties for dissociation in the presence of the laser beam and the dissociated gas at least one of reduces a quantity of debris generated and enhances removal of debris.
A laser machining method comprising the step of delivering a laser beam onto a substrate to machine the substrate, wherein the beam is delivered to a plurality of sites in a pass so as to machine the substrate at the plurality of sites, and wherein the beam is delivered to at least a portion of the plurality of sites in a subsequent pass so as to further machine the substrate at the portion of the plurality of sites, such that an extent of a heat affected zone at each site is reduced compared with an extent of a heat affected zone produced by completely drilling in sequence each via in a single pass, wherein at least one of the laser beam's laser-pulse energy, laser-pulse separation, and number-of-pulses varies from pass to pass, and wherein beam delivery is controlled to both machine a formation at each site and to provide an electrically insulating lining on a substrate wall at each site.
A laser machining method comprising the steps of:
- delivering a laser beam onto a substrate on an X-Y table positioning system using an optical system comprising a galvanometer and a non-telecentric lens to machine the substrate at a machining site, wherein the laser beam is pulsed, and wherein the laser beam is delivered at an acute angle to a surface of the substrate to form a via that is angled to the surface of the substrate;
- providing a gaseous environment around the machining site, wherein providing the gaseous environment around the machining site comprises introducing and regulating one or more gases in the gaseous environment, such that at least one of:
- (i) at least one of an oxide layer and nitride layer is grown on an internal sidewall of the via and (ii) at least one of an oxide layer and nitride layer is prevented from being formed on the internal sidewall of the via, wherein the gaseous environment comprises a gas having properties for dissociation in the presence of the laser beam and the dissociated gas at least one of reduces a quantity of debris generated and enhances removal of debris;
- and
- synchronizing the X-Y table positioning system with the galvanometer directing the laser beam and the laser beam to control a wafer position relative to an object field point at which the laser beam forms a desired angle of the angled via relative to a normal angle of the optical system,
- wherein at least one of laser-pulse energy and laser-pulse separation of the laser beam are varied during machining of the substrate according to optical, thermal and mechanical properties of the substrate being machined.
Dependencies are inferred from the claim text.