In dimensional nano- and micrometrology, single sensors are often combined into an array of sensors to enable faster
measurements by utilizing parallel data acquisition. If combined with appropriate scanning techniques, the use of sensor
arrays additionally facilitates the estimation and correction of systematic sensor errors and, thus, enables more accurate
measurements. To exploit these options, the arrays have to be aligned carefully with respect to the scanning direction,
and, in addition, the lateral distances between the sensors have to be determined with sufficient accuracy.
This presentation describes a method to align an optical distance sensor array parallel to the direction of a linear translation
stage, which is used to scan the specimen under test, and it describes a method to evaluate and determine the sensor
distances with high accuracy.
Alignment is a multi step procedure: The first step is to orientate a step edge profile perpendicular to the scanning direction
of the sensor using an M-array and an auxiliary CCD camera. In a second step, the line sensor array is scanned
across the edge using different rotation angles of the sensor. The positions where the different sensors cross the edge are
evaluated to obtain the sensor orientation relative to the scanning direction, the distances between the sensors, and their
We will show experimental data obtained with an optical line sensor array of three single sensors. The measurements
will be compared to simulated data carried out with a virtual experiment programmed at PTB. Relevant error sources are
assessed and the limitation of the method is discussed.