Abstract: An apparatus for projecting a mask pattern (MA) on a substrate (W) by means of a projection lens system (PL) is described, which apparatus comprises a device for aligning a mask alignment mark (M.sub.1, M.sub.2) with respect to a substrate alignment mark (P.sub.1, P.sub.2). Means (WE.sub.1, WE.sub.2) preventing phase differences due to reflections at the mask plate (MA) from occurring within the alignment beam portions received by a detection system (13, 13') are arranged in the path of selected alignment beam portions (b.sub.1, b.sub.1 ').

Abstract: A projection apparatus is described having a reference plate with a set of grating marks in X and Y directions for aligning with an exposure mask having similar marks, and having four detectors for each mark, and having a lens system for projecting only the relevant mark on the relevant detector. A method of projecting is also described in which the detection signals are simultaneously processed with other signals to result in a control signal to adjust image quality.

Abstract: An apparatus for projecting a mask pattern (MA) on a substrate (W) by means of a projection lens system (PL) is described, which apparatus comprises a device for aligning a substrate alignment mark (P.sub.1 ; P.sub.2) with respect to a mask alignment mark (M.sub.1 ; M.sub.2), the projection lens system (PL) forming part of the alignment device. A correction element (25) is arranged in this system (PL) to compensate for the fact that this system (PL) is not optimized for the wavelength of the alignment beam (b).

Abstract: A displacement device, particularly useful in an apparatus for the photolithographic treatment of a substrate, is provided with a holder placed on a carriage mechanism being acted upon by driving members for imparting translational and rotary movements to the holder. The carriage is constituted by a lower carriage part and an upper carriage part, each of which has a flat surface facing each other. Three linear driving members, each having a housing and a driving element projecting from both ends of the housing, and axially moving with respect to the housing, act upon the carriage. The housing of the first driving member is connected to an upper carriage part, while the driving elements of the second and third driving members are coupled to the lower carriage part with the second and third driving members respectively being connected to the first driving member in an arrangement in the shape of an H.

Abstract: An optical imaging system is described which is provided with an opto-electronic detection system for determining a deviation between the image plane of the imaging system and a second plane on which an image is to be formed by the imaging system. After a first reflection on the second plane an auxiliary beam which is obliquely incident on said plane is reflected along itself and mirror-inverted, is subsequently reflected a second time on the second plane, and is finally incident on two detectors. The difference signal of the detectors, which is a measure of the deviation, is unaffected by tilting of the second plane and by local variations in reflectivity of in said plane.

Abstract: An apparatus is described for writing patterns in a layer on a substrate by using a beam of electrically-charged particles. The apparatus is provided with an optical height-measuring system for determining a deviation between the desired and the actual position of the surface to be inscribed relative to the charged particle lens system. The deviation can be measured accurately and continuously without the use of additional markers on the substrate.