Method and apparatus for scanning a specimen using an optical imaging system

US7247825B2 · kind B2 · utility

Assignee

• Vistec Semiconductor Systems GmbH · DE

Inventors

• Dirk Sönksen · Schleusingen, DE
• Robert Mainberger · Bonbaden, DE
• Guenter Schmidt · Leun, DE

Key dates

• Filing date: Jul 8, 2003
• Grant date: Jul 24, 2007
• Expiry date: Mar 23, 2024

Classification

• Technology area (CPC G): Physics
• CPC primary: G02B21/365
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

The invention is based on an apparatus and a method for scanning specimens (1) using an optical imaging system (3) and a scanning stage (2), images of the specimen (1) being acquired by means of a camera (4), and/or measurements on the specimen (1) being made by means of an optical measurement device (5), at specimen points Xp, Yp. For that purpose, the scanning stage (2) is calibrated by obtaining and storing height values Z at different calibration positions X, Y of the scanning stage (2), and thereby generating a running height profile of the scanning stage (2). For the scanning of specimens (1), the specimen height positions Zp at specimen points Xp, Yp are determined by means of a reference height Zref of the specimen (1) together with the running height profile of the scanning stage (2). While each specimen point Xp, Yp is being traveled to with the scanning stage (2) the relevant specimen height position Zp is already being set, so that running errors of the scanning stage (2) are compensated for and image acquisitions or measurements are possible immediately upon reaching the specimen point Xp, Yp.