Mitutoyo Corporation

Lukasz Redlarski

Hideyuki Arai

Shannon Roy Campbell

Adriaan Tiemen Zuiderweg

Han Haitjema

Frans De Nooij

Hendrik Ketelaars

John Quaedackers

A metrology system is provided including a projected pattern for points-from-focus type processes. The metrology system includes an objective lens portion, a light source, a pattern projection portion and a camera. Different lenses (e.g., objective lenses) having different magnifications and cutoff frequencies may be utilized in the system. The pattern projection portion includes a pattern component with a pattern. At least a majority of the area of the pattern includes pattern portions that are not recurring at regular intervals across the pattern (e.g., as corresponding to a diverse spectrum of spatial frequencies that result in a relatively flat power spectrum over a desired range and with which different lenses with different cutoff frequencies may be utilized). The pattern is projected on a workpiece surface (e.g., for producing contrast) and an image stack is acquired, from which focus curve data is determined that indicates 3 dimensional positions of workpiece surface points.

Metrology system with projected pattern for points-from-focus type processes

A shape measuring apparatus applies, to a light beam, a periodic pattern having periodicity in a direction perpendicular to an optical axis and displaceable in the direction perpendicular to the optical axis, relatively displaces a focal point of an objective lens in a direction parallel to the optical axis, and calculates, based on amplitude of intensity of the light beam detected by a photodetector, face shape data on the object to be measured. Then, a top surface measuring step of acquiring face shape data on a top surface of the object to be measured, and a bottom surface measuring step of acquiring face shape data on a bottom surface of the object to be measured by transmitting through the top surface of the object to be measured and aligning the focal point of the objective lens on the bottom surface of the object to be measured are performed.

Shape measuring method

A method for measuring a height map of a test surface having a varying reflectivity using a multi-sensor apparatus including a pre-scan sensor and a height measuring sensor is disclosed. The multi-sensor apparatus further comprises one or more light sources configured to illuminate the test surface and a spatial light modulator. The spatial light modulator is placed in a light path between the one or more light sources and a measuring location of the multi-sensor apparatus and is configured to modulate light emitted from at least one of the light sources. The method comprises performing a measurement for determining an illumination intensity map of the test surface and a measurement for performing a height map of the test surface.

Method for measuring a height map of a test surface

In a method and apparatus for determining the height of a plurality of spatial positions on a surface of a specimen, a light beam is projected on the surface. The surface is scanned along an optical axis in different scanning positions. The light reflected by the surface is detected in scanning positions with a spatial pattern having corresponding spatial pattern positions. From the detected light for each spatial position of the surface, an envelope curve of intensity values corresponding to scanning positions is determined. A maximum of the envelope curve and its corresponding scanning position being representative of the height of the spatial position of the surface is selected. The spatial pattern is moved in a sequence of 2n steps (n&#x3e;2) in a first and a second spatial direction over a distance of &#xbc; and 1/n pattern wavelength, respectively.

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Eindhoven, Netherlands

Lukasz Redlarski