Interferometric measuring device with 2D analyzing for real-time and in situ plasma etching in the production of microsystem components

Based on the experiences made with NanoMES the interferometric in situ measuring devices in real-time and during plasma etching of micro- and opto-electronic devices GFM designed a new optical system for interference and imaging. Also the measuring program was upgraded from a 1 dimensional analysis of interference stripes to a 2 dimensional evaluation. GFM and FBH have a Patent that makes it possible to measure distances that are much shorter than the wavelength of the used laser for the interferometer. The optical positioning of the wafers in the etching chambers poses a problem for standard optical imaging, since the objects are very far from the camera lens. Therefore it is impossible to use normal long distance microscope lenses. The new modular design allows special adaptations for special problems and variable magnifications. If required a zoom lens module could be integrated. Another problem for the interferometer are vibrations and shocks. The previous NanoMES used a pulsed laser diode for stroboscopic imaging of the interference stripes. The new measuring system is able to work with a continuous mode (cw) laser. That opens the view for new possible applications. The new NanoMES is developed and tested at the FBH.