Abstract: In the course of the process for making masks with structures in the submicrometer range, initially structures of photoresist or polymer material with horizontal and substantially vertical sidewalls are produced on a silicon substrate covered with an oxide layer. This is followed by a layer of silicon nitride which is deposited by LPCVD. The resultant structure is planarized with a photoresist which is etched back until the start of the vertical edges of the sidewall coating formed by the nitride layer is bared on the photoresist structures. In a photolithographic step, a trimming mask is produced on the surface of the nitride layer and the planarizing resist. The bared regions of the nitride layer are then removed by isotropic etching. The dimensions A-B of the openings defined after removal of the nitride layer from the vertical surfaces of the photoresist structures are transferred to the oxide layer by anisotropic etching.

Abstract: Disclosed is a method of producing an integrated semiconductor structure, comprising components with dimensions in the submicron range, wherein a three-layer resist system is used to produce a polymer or resist mask. The polymer or resist mask thus produced is used to etch a layer of polysilicon on the semiconductor substrate. The method is characterized in that the pattern, produced conventionally in the top layer of the three-layer resist and including an angle < about 90.degree., is transferred by RIE, using CF.sub.4, to the center layer of plasma nitride and by RIE, using oxygen, to the bottom resist or polymer layer. In a prior art method, this was followed by lateral etching in oxygen to reduce the dimensions of the mask by a desired amount.

Abstract: A method of making via holes in a double-layer insulation of nitride and polyimide. The via holes are made with one photomask only by applying a photoresist process with double exposure, and a multi-step dry etching process. The double exposure, which includes an image-wise exposure followed by blanket irradiation, achieves an edge angle in the photoresist between approx. 60.degree. and 70.degree., depending on the exposure time ratios. This angle is transferred into the polyimide layer in a dry etching process. In a first etching step with CF.sub.4 as etching gas the greater part of the polyimide is removed. For removing the residual polyimide in the via holes there now follows an etching step in O.sub.2. Etch bias is thus kept on a very low level. The nitride layer is then etched with CF.sub.4 as etching gas, with the etching process being executed in two steps, each followed by an etching step in O.sub.2 for laterally shifting the photoresist and the polyimide via the resist angle.

Abstract: For mutually aligning (registering) mask and substrate in X- or corpuscular ray lithography, an electron beam (16) is used which extends collaterally to the exposure beam (ion beam or X-ray) and which is suppressed during the actual exposure process. For coupling the electron beam to the exposure beam path, a magnetic field (7) is used. The accurate relative position of mask and substrate is determined during alignment by tilting the electron beam. Fine alignment during exposure is effected by suitably tilting the ion beam or shifting the substrate relative to the X-ray. The mask (10) used for exposure consists of a very thin silicon layer with a pattern area (M) and a registration area (R) spatially separated therefrom. The registration area consists of a plurality of openings, the pattern area of blind holes.

Abstract: On a substrate (1) covered with a chromium layer (2), a positive resist layer (3) is applied, exposed through an exposure mask with the mask pattern corresponding to the negative of the respective chromium pattern, developed, and blanket-coated with a less than or equal to 10 nm thick layer (4) of silicon dioxide. Then photoresist layer (3) and the silicon layer (4) thereon are lifted off, and finally the chromium layer (2) is dry-etched, the remaining silicon dioxide layer (4) being used as an etch mask.Chromium masks are used e.g. in the production of semiconductor circuits. By means of the reverse process, structures whose smallest dimensions are in the micrometer and the submicrometer range can be transferred into chromium layers with sharp edges.