Abstract: A method for plasma etching a shallow recess or shallow trench at a predetermined depth by illuminating a wafer with a light source and using a spectrometer to receive the light reflected from the wafer begins with a step of detecting an etch start time, either by detecting a time of plasma ignition, as extracted from reflectance data, or a time extracted from the reflectance data when a wafer reflectance signal is observed to begin to change after a residual layer is etched away prior to beginning a recess or trench etch. The next step is measuring a reflectance intensity of light reflected from the wafer. Preferably, a plasma background signal is removed from this measurement and an array detector is used wherein the wavelength is determined using the reflectance model. Next, an etch rate is determined by fitting data representing the collected reflectance signal to the wafer reflectance model as a function of time, and extracting the etch rate from the model.

Abstract: A method and apparatus are provided for measuring a depth geometry of a structure on a semiconductor substrate including a plurality of recessed and non-recessed portions, wherein one of the recessed and non-recessed portions includes a reference interface and one of the recessed and non-recessed portions has a dielectric layer thereon. A broadband light source irradiates the substrate and a detector detects a first spectral component comprising light reflected from the non-recessed portions, a second spectral component comprising light reflected from the recessed portions, and a third spectral component comprising light reflected from the dielectric layer. Spectral reflectance information of the detected rays is stored and a plot of reflectance intensity versus wavelength is generated. A depth geometry of one of the recessed portions and the dielectric layer are determined relative to the reference interface, based on an interferometric analysis of the plot.

Abstract: The process for low-emission drying of a substance in a drum-type drying installation is suitable in particular for sewage sludge, fish meal and sludges from starch factories, soap factories and paper mills, which substances are preferably to be converted into granules. The process is likewise very suitable for drying biomass products such as wood chips, grass, sugar beet chips and the like, since the emissions are very greatly reduced by means of this process. The drying process is carried out in such a way that no unpleasant odors and dusts are emitted to the outside, because the actual drying circulation is closed. Fossil fuels are used as the heat source for the burner for heating this air stream.

Abstract: An optical switch for transmitting light between a first location and a selected one of a plurality of second locations. The switch includes a mirror having a concave, reflective surface and an axis. The switch also includes a plurality of fiber optic cables, one of which is disposed at the first location and the remainder of which are disposed at the second locations, each cable having a light transmission face at their respective locations. The light transmission face at the first location is substantially parallel to the focal plane of the mirror. The light transmission face at each of the second locations is at an angle which intersects with the axis. A motor connected to the mirror for eccentric rotation thereof with respect to its axis to direct light between the first location and individual ones of the second locations depending upon the rotational position of said mirror about the axis to complete the light switch.