Vistec Semiconductor Systems Gmbh

Guenter Schmidt

Albert Kreh

Robert Mainberger

Dirk Sönksen

Michael Halama

A semiconductor substrate or wafer inspection device for detecting defects on wafer surfaces includes an air-cushion stage which can be displaced in two directions (X,Y) that are perpendicular to one another. Several air nozzles are provided for this purpose. At least one valve is connected to at least one electric control unit, the valve being configured in such a way that a normal pressure prevails in the air nozzles when the electric control unit delivers a corresponding signal.

Wafer inspection device

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

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Leun, Germany

Guenter Schmidt