IMMS has developed a vertical drive to raise and lower objects through 10 mm under active control with nanometre precision.
To date, manufacturers have always found it extremely difficult to raise loads in the region of 10 kg for industrial purposes and to hold them in a precise position. Nanometer accuracy was always subject to compromise. The very possibility has come through electromagnetic vertical actuators with pneumatic gravity compensators, which can be integrated into many existing precision drive systems.
Systems of this kind are used for purposes which include semi-conductor technology, for instance in order to position reticles. The jigs needed for measuring and structuring such things as substrates, wafers and reticles usually have an (x,y) stage in order to move the object with extreme precision within a plane.
These objects are not uniform in height: there is variation in the thickness of wafers and masks or the height of the reticle supports. Besides, the procedures themselves are carried out in different levels. Here one example is the measuring of stacked images behind an exposure mask and another example the structuring of wafer layers. Such layers are often only a few nanometres thick; an entire wafer may have a thickness between 0.7 and 0.9 mm. Rises in temperature of only 0.01 K, for instance, cause such a measurement error when a reticle is being measured that the integrated circuits to be produced with it would fail.
IMMS has now developed a vertical drive to raise or lower objects with nanometre precision and active control through a range of 10 mm. The raising and lowering is achieved by pneumatic gravity compensation. This controls the amount of force to be applied by the vertical electromagnetic drive by constantly approximating it to zero. As a result there is in effect no current flowing in the actuator coil, which means there is no unwanted source of heat in the measuring space (which would interfere with the necessary precision of measurement by causing expansion of the materials).
The new drive will enable objects to be brought into position with no Abbe error, at much greater accuracy than previously for sampling or processing.
The drives previously on the market, even those working in a vacuum, can now be fitted with this new system and will thus be vastly improved. All that will be necessary is to install three of the new actuators on one platform of a positioning system. The effect will be not only exact manipulation of the height of the load but also extremely sensitive control of the tilt of the platform.
Acronym / Name:AFiA / Aerostatic guiding element with integrated actuator for precision drive systems
Duration:2015 – 2017
Application:Research institutions and ultra-precision mechanical engineering|Measurement| positioning and structuring of substrates| wafers and reticles
Research field:Magnetic 6D-direct drives with nanometre precision
Michael Muth, AeroLas
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“We have for many years been appreciative of our cooperation with IMMS. The results from this project will be the basis of product design to the specification of future AeroLas customers. IMMS will likewise be an important partner for us in future developments because of its outstanding expertise in the field of magnetic drives.“
Dr.-Ing. Ludwig Herzog
Head of Mechatronics
ludwig.herzog(at)imms.de+49 (0) 3677 874 93 60
Dr. Ludwig Herzog will provide detail on our research on magnetic 6D direct drives with nm precision for the nm measurement and structuring of objects. He supports you with services for the development of mechatronic systems, for simulation, design and test of MEMS as well as for finite element modelling (FEM) and simulation.
The AFiA project has been funded by the German Federal Ministry for Economic Affairs and Energy (BMWi) in accordance with parliamentary decree under the reference KF2534513PO4.