Abstract: As interferometer, especially for length measurement, with a laser light source (2) and a beam divider (7) to divide the laser light into a measuring and a reference beam which, after passing along geometrically separate paths, interfere in at least one recombination device (15), and with a photoelectric detector device (3) to evaluate the interference signals from the recombination device(s) (15). A flexible optical fibre (5) to guide the laser light is arranged between the laser light source (2) and the actual interferometer with the beam divider (7). In order to ensure the optical operation of the interferometer independently of external effects on the laser light-guide optical fibre, the interferometer has a polarising device (11) to establish a defined, preferably linear polarisation of the laser light at the input of the beam divider (7) which is advantageously arranged behind the flexible laser light-guide (5) and in front of the beam divider (7).

Abstract: The invention relates to an interferometer head with a rigid bearer or casing to which a beam divider for the spatial division of laser light into a measuring and a reference beam and at least one recombination device are firmly secured (adhesively), where a reference beam guided by a reference path in the interferometer head and a measuring beam or part thereof guided by a movable measuring mirror of reflective measuring surface interfere to form at least one optical interference signal.

Abstract: In an interferometer for measuring displacements of a movable structural component, comprising a measurement interferometer arrangement (1), a partial beam traverses a measurement branch of variable optical length and is guided by an adjustable reflector system (11) connected to the movable structural component. The measurement interferometer arrangement (1) is arranged, together with the adjustable reflector system (11) including the whole measurement branch, in a sealed housing (3) which also contains a wavelength measuring device (2) for measuring the wavelength of the partial beam which travels through the measurement branch in a gaseous medium. A ventilator device (14) produces an air current in the housing (3), so that identical conditions, in particular identical temperature, pressure and humidity, always prevail in the medium in the measurement branch and in the spatially separate wavelength measuring device (2).

Abstract: To adjust a device for the projection copying of masks on a semiconductor substrate, adjustment marks are illuminated with wideband adjustment light in order to make variations in the intensity of the reflected signal in the area of a mark field. The color defect created by the wideband nature of the adjustment light is eliminated by an achromatization device which covers only a part of the total picture field which contains the adjustment marks.

Abstract: To adjust a device for the projection copying of masks on a semiconductor substrate, adjustment marks are illuminated with wideband adjustment light in order to eliminate variations in the intensity of the reflected signal in the area of a mark field. The color defect created by the wideband nature of the ajustment light is determined by spectroscopic means and taken into account when making the adjustment.

Abstract: An apparatus for determining the focus state of a system for the projection exposure of a mask on a semiconductive substrate for producing integrated circuits without relatively displacing the mask, projection objective and substrate along the common optical axis, utilizes an arrangement for varying cyclically the optical path length for rays at least arising from a projected image on the substrate and running through the objective to a detector plane so that an intensity measurement of the light intensity at this plane indicates the path length required for sharpness and hence the focus state of the projection assembly.

Abstract: For a device for projection copying of masks on a semiconductor substrate for the manufacture of integrated circuits, it is intended that the copying of an adjusting mark of the workpiece onto a sensor takes place by means of the projection lens, whereby the directly reflected beams of the light which makes visible the adjusting mark are masked out by a mirror, and the position-sensitive sensor is fastened at the underside of the frame carrying the mask.

Abstract: Using a photolithographic projection apparatus a mask having a pattern is imaged on a photosensitive layer coating a semiconductor substrate by a projection lens. To improve the resolving capability and to obviate adverse effects, e.g. standing waves and inhomogeneous exposure, the space between the substrate and the adjacent boundary face of a projection lens is filled during exposure with a transparent liquid having the same refractive index as the photosensitive layer.

Abstract: In a photolithographic method for the manufacture of integrated circuits a mask having a pattern is imaged on a photosensitive layer coating a semiconductor substrate by a projection lens. To improve the resolving capability and to obviate adverse effects, e.g. standing waves and inhomogeneous exposure, the space between the substrate and the adjacent boundary face of a projection lens is filled during exposure with a transparent liquid having the same refractive index as the photosensitive layer.