Leica Microsystems Cms Gmbh

Leica Microsystems Jena Gmbh

Thomas Iffland

Joachim Wienecke

Gert Weniger

An optical measurement system having a spectrophotometer and a ellipsometer is calibrated, the spectrophotometer and the ellipsometer first being calibrated independently of one another. A spectrophotometer layer thickness (d) of a specimen is then determined at an initial angle of incidence (&#x3b8;) using the spectrophotometer. An ellipsometer layer thickness (d) of the specimen is then determined using the layer thickness determined with the ellipsometer. The spectrophotometer and the ellipsometer are matched to one another by varying the initial angle of incidence (&#x3b8;) until the absolute value of the difference between the spectrophotometer layer thickness (d) and the ellipsometer layer thickness (d) is less than a predefined absolute value.

Method for wavelength calibration of an optical measurement system

A sample P is illuminated by a measurement light beam with an incidence angle differing from 0&#xb0;; light reflected therefrom is detected; intensity values are recorded and evaluated; and the opening of a field stop is imaged onto a receiving surface, thereby generating an image. In such a method, a value of 'light' or 'dark' is allocated to each intensity value as a function of a brightness threshold; the smallest rectangle that encloses all &#x201c;light&#x201d; positions on the receiving surface is determined; the geometric center point of that rectangle is determined; the position of that point is compared with the position on the receiving surface that corresponds to the geometric center point of the image generated by the field stop in the focused state; and a change in the distance between the sample and the imaging optical system corresponding to the distance between the two points is effected.

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Jena, Germany

Thomas Iffland