Laser beam machining

US8389893B2 · kind B2 · utility

Assignee

• Nanoscribe Holding GmbH · DE

Inventors

• Michael Kempe · Jena, DE
• Peter Westphal · Jena, DE
• Wolfgang Grau · Böblingen, DE
• Georg von Freymann · Toronto, CA

Key dates

• Filing date: Nov 20, 2008
• Grant date: Mar 5, 2013
• Expiry date: Feb 16, 2029

Classification

• Technology area (CPC G): Physics
• CPC primary: G03F7/70383
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A method for laser beam machining of a workpiece in which a laser beam is focused by an objective, into or onto the workpiece having a boundary surface, to produce a machining effect by a two-photon process, and the position of the focal point with respect to the workpiece is shifted. To obtain a reference for the position of the focal point, an image of a luminating modulation object is projected through the objective onto the workpiece into the focal plane or so as to intersect it. Reflections of the image occurring at the boundary surface are imaged into an autofocus image plane, and are detected by a camera. The camera image plane either intersects the autofocus image plane when the image of the illuminating modulation object lies in the focal plane, or lies in the autofocus image plane when the image of the modulation object intersects the focal plane.