Volume 78, Issue 3 -

The most important principle, the basis and operation of heterodyne and homodyne interferometers are discussed. Their benefits and limitations are covered based on a metrological analysis. The resolution of interferometers can be determined by calculating the smallest resolvable distance increment. An Abbé-error-free design is explained using interferometers by means of a nanopositioning and nanomeasuring machine developed at the Institute of Process Measurement and Sensor Technology (Ilmenau University of Technology) and manufactured at the SIOS Messtechnik GmbH Ilmenau, Germany.

The contribution provides an overview on new developments of standards and measurement methods for 3D-micro- and nanometrology with a focus on work at PTB. These developments target at a reduction of measurement uncertainty of instruments used for dimensional characterization of micro- and nanostructures.

The paper presents the result of a round robin test of the measurement of a naturally grown silicon plateau structure with optical and tactile measuring instruments. The silicon standard shows isles with a diameter of about 800 nm and a heigth of about 12 nm. Lateral and vertical dimensions, isles with changing distances, and a ideally flat surface as basic material allow the calibration of the sensor properties, the step height, the spacing, and the resolution as well as the guide straigthness.

The uncertainty of dimensional measurements with computed tomography (CT) can be derived based on calibrated work pieces. The method can be utilized to estimate different influences on the measurement value as well as proving the capability of measurement processes. Both ways of utilizing the method are given in an example and advantages and disadvantages are discussed.

In mechanical engineering coordinate metrology belongs to the key elements of quality management. Its application may help to master challenges posed by geometrical testing in micro technology if practical problems of tactile micro probing can be solved. With smaller probing elements — prerequisite for probing micro features — limiting static and dynamic probing forces to a beareable level for workpiece and probing system is getting disproportionately more difficult. A non-contacting 3D micro probing system based on electrical interaction has been developed and investigated at the chair Quality Management and Manufacturing Metrology of university Erlangen-Nuremberg, which can be applied as an alternative to tactile 3D microprobes for 3D imcro coordinate measurements as well as for nanometer resolved topography measurements.

The requirements for the coordinate measuring technology has rapidly been increasing during the past two decades. The number of measurands per workpiece raised,the measurement objects became more complex, cycle times decreased, and the tolerances to be tested were reduced. The measurement tasks can often not be carried out longer by only one measurement device or sensor principle. With multi-sensor coordinate measuring machines a higher flexibility is reached. Measurements with several sensors can be carried out in one measurement run. Time and costs are saved and the measurement uncertainty is reduced. Multisensor coordinate measuring machines have therefore achieved widespread use in today´s industrial metrology.

The requirements on surfaces in modern engines are increasing due to more efficiency and sustainability requirements. The trend is more and more towards complexly structured surfaces with randomly arranged structures. Composite materials combined with complex production processes are employed that are no longer robustly controllable with tactile surface measurements. The required changes and flexibility can only be covered by using well known 3d-optical measurements combined with function-oriented parameters.