Steag Hamatech Ag

Steag Eta-optik Gmbh

Rolf Hertling

Wilbert Windeln

Wolfgang Schaudig

In order to determine geometric structures and/or material parameters on or in substrates and in a locally resolved manner over the substrate surface, the invention provides the following measures: Measuring reflection and/or transmission light intensity values of the diffracted light according to the wavelength; calculating the reflection and/or transmission light intensity values using an iteration model into which the individual layer-structure and/or material parameters enter, and; modifying the parameters until the measured and calculated values coincide to the greatest possible extent.

Method for determining geometric structures on or in a substrate as well as material parameters

According to the inventive method for determining the thickness of at least one layer provided on a substrate, the measurement can be constructed simply and reliably and a reliable measuring result can be obtained by measuring reflection&mdash;and/or transmission light intensity values of zero order in dependence on the wavelength and calculating said reflection&mdash;and/or transmission light intensity values using an iteration model which is dependent on the individual layer parameters. The layer parameters are altered in order to introduce a consistency between the measured values and the calculated values and the substrates have geometrical structures whose geometrical dimensions are used as further parameters of the iteration model. The inventive method also provides a means of determining the geometry of structures in the substrate, for example the depth, width and the repetition interval of grooves in a blank for geometrical storage media, such as CDs.

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Aachen, Germany

Rolf Hertling