Method and device for optically examining structured surfaces of objects

US6633375B1 · kind B1 · utility

Assignee

• Leica Microsystems Semiconductor GmbH · DE

Inventors

• Michael Veith · Sankt Ingbert, DE
• Volker Knorz · Gammertingen, DE
• Edgar Maehringer-Kunz · Sindelfingen, DE

Key dates

• Filing date: Sep 29, 2000
• Grant date: Oct 14, 2003
• Expiry date: Sep 29, 2020

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L22/12
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A method and an apparatus are described for the optical examination of structured surfaces of objects, especially of wafers and/or masks. The optical apparatus has an observation beam path (6) whose central axis (42) is directed vertically against the surface of the object (16), an illumination beam (2) whose central ray (40) falls vertically on the surface of the object, and an illumination beam (3) whose central ray (41) falls obliquely onto the surface of the object (16). In the observation beam path (6) the image of the surface of the object (6) is observed and/or detected. In the observation beam path (6) a filter device (38) and/or detector device (18) is disposed. The optical system has an illumination device (39) for the simultaneous production of a dark field illumination, a device for the coding (11) of the illumination beams (2, 3) being associated with the bright field (2) and/or the dark field illumination beam (3).