KTH sets a world record in measurement
KTH’s efforts have led to a record improvement in optical profile gauge performance. This measuring instrument is of great value, primarily to the MEMS industry (microelectromechanical systems). Lars Mattsson, Professor of Production Measurement Engineering, is the person responsible for this achievement.
Lars Mattsson implemented a qualitative evaluation of measurement resources for the European research network 4M Network of Excellence, and has examined the fields where there are insufficient suitable measurement methods. One of these is the measurement of microstructures in replicated plastic surfaces that are of larger size vertically than horizontally; with, for example, 100 micrometers (um) depth and 10 um narrow channels.
Through cooperation with Forchungscentrum Karlsruhe in Tyskland, Lars Mattsson gained access to a number of star-shaped objects to measure. These exhibited extreme relationships between height and width that varied from 4:1 to 200:1.
“Equipped with these samples I carried out tests on four optical measuring instruments and found, to everyone’s surprise, major measuring faults. With these results in my hand I went to one of the major American manufacturers of optical profile gauges and reported what I had found out about their instrument. An identical measurement carried out on site confirmed that the fault was also present in their newest system,” described Lars Mattsson, who is responsible for the Measurement Engineering Division of the 4M Network of Excellence.
“We were able to improve the instrument’s optic so that we managed to measure 400 um deep structures that were 8 um wide at both the bottom and the top, in other words a 50:1 height/breadth relationship, which is a new world record for an optical profile gauge. There are certain measurement faults still remaining on the horizontal but these are down to one or two micrometers,” say Professor Mattsson.
Christer Gummeson