Showing papers on "Photomask published in 1981"

Automatic photomask inspection method and system

Abstract: A method and apparatus for receiving two sets of digitized scan data from two optical detectors which simultaneously scan two supposedly identical portions of a photomask for comparing the two sets of scan data to detect defects, and for evaluating the defect data to determine whether or not it represents real defect information or false defect information. Scan lines containing defect data are scanned twice to produce two sets of defect data and the two sets are then compared to produce a real defect data set including only defects detected in both scans. False defects are thus eliminated from the final data set.

System for design and production of integrated circuit photomasks and integrated circuit devices

Abstract: System for design and production of integrated circuit photomasks and integrated circuit devices wherein the four adjacent corners of each circuit topography pattern on each photomask and each wafer chip area are set aside as designated information locations. One of the designated information locations containing a two-dimensional rectangular array of locations for use as a mask sequence array and a second of the designated information locations containing a two-dimensional rectangular array of locations for use as an alignment key pattern array. The third designated information location serves as a product identification area which may include a manufacturer name and a product identification code. The fourth designated information location is adapted to serve as a test device area and may also serve as a part identification area in semiconductor processes employing a two layer metal interconnect system.

Photomask and photomask blank

Abstract: In a low reflection type photomask (hard mask) having a tantalum masking film provided, through or without an intermediary low reflection layer, on a transparent substrate and further having a low reflection layer provided on the tantalum layer, use is made of a composite layer containing tantalum oxide and tantalum nitride as the low reflection layer. The etching speed of the composite layer is faster than that of the tantalum oxide layer conventionally used as low reflection layer, being substantially equal to that of the tantalum film, and there is very little lowering of the dimensional precision of the photomask obtained due to the difference in etching speeds. Further, dry etching is applicable for the above multilayer masking film containing the composite layer and the masking tantalum film, and there is little lowering of the dimensional precision even by overetching.

Photomask and photomask blank

Abstract: In a photomask (hard mask) blank having a masking film of metallic chromium, chromium oxide, or the like, formed on a transparent substrate, there are interposed between the transparent substrate and the masking film a translucent and electroconductive film made of molybdenum, tantalum or the like and a translucent and chemically resistant protective film made of aluminum oxide, silicon oxide or the like, in the order mentioned from the side of the transparent substrate. The photomask obtained from this photomask blank is free from distortions or defects of transfer patterns caused by generation of electrostatic charges and also exhibits excellent durability in repeated uses, with intermediate repeated chemical washing.

Defect-free photomask

Abstract: A process for forming a defect-free photomask consisting of an opaque layer overlying a substrate transparent to radiant energy and which comprises applying a coating material which absorbs radiant energy to the surface of a substrate, directing a beam of radiant energy through the substrate onto the coating material so as to fuse the coating material and the substrate at their interface thereby forming an opaque layer on said substrate, and removing from the surface the unfused coating material.

Photomask blank and photomask

Abstract: A photomask is fabricated by forming, in a photomask (hard mask) produced by forming a patternized film of a masking material comprising (a) a layer of metallic chromium and (b) a layer of chromium oxides superposed thereon, a film of a translucent and electroconductive material selected from Nb, Ta and V, between the masking film and the transparent substrate At the time of pattern transferring by photolithography, dropping off of parts of the pattern of this photomask does not occur even when it includes isolated island-like parts, and, at the time of inspection by electron-beam exposure, the precision of inspection does not lower This photomask is obtained by patternizing by selective etching the masking film of a photomask blank produced by successively forming, on the transparent substrate, the translucent and electroconductive film and the masking film

System for specifying critical dimensions, sequence numbers and revision levels on integrated circuit photomasks

Abstract: A system for specifying critical dimensions, mask sequence levels, and mask revision levels on integrated circuit photomasks and chips involving use of a patterned array of geometric regions containing preselected indicia in each region corresponding to the mask sequence number for an associated photomask. The preselected indicia may be either a critical diemension pattern to integrate the mask sequence indicia with the critical dimension specification or a mask revision level code to integrate the mask sequence number with the revision level, or a combination of both a critical dimension pattern and a mask revision level code. In the latter case the mask revision level code is integrated with the critical dimension pattern to conserve space on the photomask and the IC chip.

System for providing photomask alignment keys in semiconductor integrated circuit processing

Abstract: A system for providing photomask alignment keys in semiconductor integrated circuit processing involving selecting a common photomask subarea to be utilized as an alignment key pattern area on each photomask in the set with the alignment key pattern area having an array of sequential key locations. Each photomask after the first has a designated alignment key location which is either the same alignment key location as the immediately preceding photomask or the next alignment key location in the array. A mask key pattern is formed on the first photomask comprising aligning keys for all the associated higher numbered photomasks designed to be aligned to topography created by use of the first photomask in accordance with a mask alignment formula with each of the aligning keys being formed at key locations corresponding to the designated alignment key locations for the associated photomask. On each of the remaining photomasks of the set a mask key pattern is formed comprising an alignment key at the designated alignment key location and aligning keys for any associated higher numbered ones of the photomasks designed in accordance with the mask alignment formula to be aligned to the topography created by use of each photomask with each of the aligning keys being formed at a key location corresponding to the designated key location for the associated photomasks. On each photomask having a mask sequence number greater than two and being the first photomask in the set to have a particular designated alignment key location, a used key pair blot mark is formed at a key location immediately preceding the designated alignment key location for the mask. The alignment key assignment process together with the use of used key pair blot marks provides a self-instructing alignment key pattern on each photomask to avoid having to make reference to extrinsic alignment instructions.

Hinged glass photomask assembly

Abstract: A method and article are disclosed for facilitating repeated use in a photolithographic imaging process of a photomask assembly comprising a pair of glass plates by means of a flexible polymeric hinge permanently joining said pair of glass plates.

Method for repairing glass photomasks

Abstract: A method for repairing defects in the form of discontinuities in a photomask pattern in or on a glass substrate by means of electroless deposition of a nickel-containing coating on the surface of a glass substrate is disclosed.

Manufacture of photomask

Abstract: PURPOSE:To simplify a photomask manufacturing process and increase the accuracy of the photomask by exposing a radiation sensitive org. resist film, to electron beams, which is opaque to ultraviolet rays or far ultraviolet rays. CONSTITUTION:Radiation sensitive org. resist film 3A which is opaque to ultraviolet rays or far ultraviolet rays is directly formed on substrate 1, and a desired pattern is formed in film 3A by exposure to electron beams, development and post- baking. Using the residual portion of film 3A as a light shielding portion, pattern printing is carried out with ultraviolet rays or far ultraviolet rays. Thus, the formation of a light shielding film, the etching of the film and the removal of the residual resist film are made unnecessary as compared to a conventional method, resulting in a simplified process.

Manufacture of photomask

Abstract: PURPOSE:To obtain a photomask of high accuracy by coating a resist film on the surface of a transparent glass substrate, forming resist patterns, irradiating ion beams to blacken the patterns and subjecting the same to fluoride plasma treatment thereby hardening the surface. CONSTITUTION:A positive type photoresist soln. is coated on the surface of a transparent glass substrate 1 such quartz glass substrate to form a photoresist film 2 of about 0.75mum thickness. Thence, it is subjected to pattern exposure with a photo repeater, and after the exposure, the substrate is immersed in a developing soln. to be developed, whereby a photoresist pattern 3 of a desired shape is obtained. Next, the substrate 1 is subjected to ion implantation, thence it is set and is irradiated with ion beams 4 of high energy, to form the resist pattern 3 into the blackened pattern 5. This blackened pattern 5 is subjected to fluoride plasma 6 treatment, whereby tetrafluoroethylene resin layer 7 is formed on the blackened pattern 5 is hardened, and the intended photomask is thus obtained.

Raw material of photomask

Abstract: PURPOSE: To obtain a raw material of photomask excellent in resistance to a washing soln of strong acid for enabling repeated uses, and enhanced in etching performance, by providing a layer containing a lower metal oxide or a lower metal nitride on a substrate CONSTITUTION: A layer containing a comparatively lower oxide of a metal selected from a group of Cr, Ti, Mo, Ta, and W or a comparatively lower nitride of it is formed on a substrate by a method of sputtering or the like On this layer another layer containing both of the higher oxide and higher nitride of the same metal or another layer containing only the metal nitride is prepared to obtain an intended photomask raw material Since the obtained photomask raw material has the laminated layers containing the oxides or nitrides of the same metal differing in oxide or nitride degree on the substrate, it has excellent resistance to a washing soln of hot concd Sulfuric acid or the like, and can be repeatedly used COPYRIGHT: (C)1983,JPO&Japio

Photomask blank and its manufacture

Abstract: PURPOSE:To manufacture a photomask blank with a small extent of undercut and wide surface spectral reflectance by forming a chromium film contg. chromium carbide on a transparent substrate by a sputtering method. CONSTITUTION:A chromium film contg. chromium carbide with about 3 optical density is formed on a precisely polished glass substrate by sputtering a gaseous mixture of methane with Ar under about 1X10 Torr total pressure. Thus, a photomask blank is manufactured.

Surface Conversion for Antisticking to Reduce Patterning Defects in Photolithography

Abstract: After an exhaustive reevaluation of the contact printing processes, photoresist sticking to the photomask surface is identified as the principal cause of patterning defects and a preventive measure is developed. This process, called surface conversion for antisticking (SURCAS), facilitates a reduction in defect density by about one‐fourth compared to conventional contact printing. This technique opens the way for improvement of current LSI fabrication, and moreover should be useful in ultrafine pattern lithography down to 1 μm in the near future.

Dual-polarity, single-resist mixed (e-beam/photo) lithography

Abstract: A lithographic process is described which involves electron-beam exposure of the small geometries of an integrated circuit pattern and optical exposure of the large geometries onto the same resist layer. A single development step produces both electron and optical images. With the use of a diazo-type resist, either positive or negative e-beam images can be obtained, so that suitable selection of the photomask tone allows complete flexibility in the choice of polarity of the composite pattern. Using AZ-2415, e-beam defined features as small as 0.4 µm joining large optically defined pads have been produced in doped polysilicon by plasma etching.

Method and device for correcting white spot defect of photomask

Abstract: PURPOSE:To correct a white spot defect, by bringing a metal film on a correction plate and the pattern surface of a mask into tight contact with each other and irradiating laser light upon a white spot defect portion to vaporize the metal film. CONSTITUTION:A metal film 9b provided on a correction plate 8, which is manufactured by coating the metal film on a glass plate 9a, is overlapped on the surface of the Cr pattern 2b of a glass plate 2a. Exhaust is effected by vacuum to bring a photomask 1 and the correction plate 8 into completely tight contact with each other. When the dimensions of a rectangular opening 24 projected onto the surface of the mask are adjusted to a white spot defect 4, another rectangular opening 26 is moved in connection with the adjustment to concentrate laser light 21 onto the metal film 9b in the same shape and dimensions as the image of the opening 24 to vaporize the metal film and correct the defect. According to this method, the projected shape and dimensions of the laser light can be adjusted to the defect from the side of an observer to perform working and the number of working steps is greatly reduced.

Process for forming a defect-free photomask or repairing defects in an existing photomask and product thereof

Abstract: A process for forming a defect-free photomask consisting of an opaque layer overlying a transparent substrate or for repairing transparent defects in an opaque layer (chromium film) overlying a transparent substrate which process comprises applying a coating material (coating material) which absorbs radiant energy to the surface of the substrate, directing a beam of radiant energy (laser) through the substrate onto the coating material at points to be made opaque so as to fuse the coating material and the substrate at their interface thereby forming an opaque layer (treated area) on said substrate, and removing from the surface the unfused coating material (residue)

Manufacture of photomask

Abstract: PURPOSE:To obtain a photomask having a fine and accurate mask pattern faithful to a resist pattern by treating a mask substrate with an inorg. alkali soln. prior to an etching stage so as to enable uniform etching independently of a resist scum layer remaining on the mask substrate. CONSTITUTION:A mask substrate is coated with an electron beam resist polymer contg. halogen represented by the general formula such as polytrifluoroethyl alpha-chloroacrylate, and the coated substrate is pattern wise exposed to electron beams and developed. The mask substrate is then treated with an aqueous soln. of inorg. metallic salt prior to chemical etching. Thus, defects during chemical etching due to a resist scum layer remaining on the substrate after development can be eliminated thoroughly, and the resulting photomask has a small pattern conversion difference and is faithful to the resist pattern, fine and accurate.

Photomask for producing semiconductor devices

Abstract: A photomask comprises a transparent substrate on one surface of which a mask pattern is formed of a photoshielding film and the opposite surface of which is roughened in order that rays of incident light are refracted diffusedly through the rough surface and the images of minute particles of dust disappear in the projected pattern.

Formation of pattern

Abstract: PURPOSE:To form patterns different from that of a photomask is designed by a method wherein a workpiece surface provided with a recess is covered with a photoresist layer, thick in the recess and thin on the other part, and is exposed to light, with an exposure less than proper on the recess and more than proper on the other part, with a traveling pattern creating different results from those expected for the mask. CONSTITUTION:The surface 2 of a workpiece 1 made of Si, etc., is provided with a recess and the photoresist layer 3 is thick in the recess and thin over the other part. Because the exposure effect of the light 7 depends upon the thickness of the photoresist layer, the effect on the recess is less than proper and more than proper on the other part. Therefore, the region 13 exposed less remains constituting a selected pattern when the developing process is completed. Thus, a difference in photoresist layer thickness results in a pattern different from other pattern such as photomask.

Photomask for projective exposure

Abstract: PURPOSE:To prevent dewing on the pattern surface of a photomask for projective exposure and to minimize the lowering of illuminance, by filling the gap between the photomask and cover glass with a transparent liquid. CONSTITUTION:To frame 12 provided outside of active pattern region 11 of mask 10, cover glass 14 is stuck and in the internal space formed of them, transparent liquid 15 is injected and sealed. Since the gap between mask substrate 10 and cover glass 14 is filled with transparent liquid 15 with a nearly equal refractive index, reflection on the mask surface can nearly be eliminated. Further, since the pattern surface of the mask is not exposed to the air, no dewing occurs and the lowering of illuminance due to the stucked cover glass can be minimized.

Gas etching method

Abstract: PURPOSE:To perform the uniform etching corresponding to predetermined patterns by covering the surface to be etched having been covered with a mask with aperture forming plates and performing etching locally or progressing the same gradually from local to the entire part of the etching surface CONSTITUTION:In a gas etching apparatus, a photomask blank 3 is covered with aperture forming plates 4 made of an etching-resistant material to form an aperture opposing only to the central part of the photomask blank 3 The central part is lightly etched locally, and the aperture is gradually expanded by gradually moving the aperture forming plates 4 in the arrow directions so that in the final the entire part of the photomask blank 3 is exposed into the plasma Thereby, the differences in etching rate between the peripheral part and central part of the photomask blank 3 are eliminated and the uniform etching patterns may be obtained

Photomask for mfg. very small semiconductor structures - where metal mask pattern is located on raised zones of glass substrate

Abstract: The mask consists of a transparent substrate on which a continuous masking material (I) is deposited and then etched by photolithography to leave a mask pattern (Ia). The substrate is next selectively etched so the pattern (Ia) is located on raised zones of the substrate. Layer (I) is pref opaque and made by the vapour deposition of a metal such as chromium. The pref mask making method consists of coating a substrate with a metal (I), which is etched via a photolacquer mask to obtain pattern (Ia). The substrate is then etched to leave projecting zones on the pattern. The projecting zones are removed. Layer (I) may alternatively consist of semitransparent Fe203 or Cr203. Used e.g. in mfg semiconductor structures 1 micron wide using electron beams or X-rays as the exposure medium. The mask provided reduces the scatter of electron- or X-ray- beams, and is inexpensive.

Method and apparatus for amending a photomask

Abstract: A method for amending a defective mask pattern of a photomask (7) is disclosed, with a microscope and light projecting apparatus for carrying out the method. A pattern component (3) of a normal mask pattern is irradiated by a spotlight (2, figure 6). The normal mask pattern has the same pattern layout as that of the defective mask pattern (6°, figure 7) to be amended. The shape of the spotlight (2) is accurately aligned with the shape of the pattern component (3) which is the same pattern as the component of the defective mask pattern to be amended. At least one base mark (4a,4b) is aligned with at least another pattern component (5a,5b) near the irradiated portion. The base marks may be perpendicular lines on transparent plates in an adjustable eyepiece of a microscope used to view the photomask. Then the position of the base mark relative to the position of the irradiated portion is fixed. After that, the normal mask pattern is replaced by the defective mask pattern. The base mark is aligned accurately in the same way with a corresponding pattern component (5a', 5b') near the defective pattern component. The spotlight (2) then irradiates the defective mask pattern, the luminous intensity of the spotlight being intensified or its wavelength shortened so that it can amend the defective pattern component, or a photoresist coating (31) on the component.

Method and apparatus for exposing photomask

Abstract: PURPOSE:To obtain a pattern of high accuracy by irradiating a photoresist with light for detecting the thickness and correcting the extent of exposure according to the state of the reflected light when reticle patterns are contracted and arranged on a hard plate with the photoresist applied and the photoresist is exposed. CONSTITUTION:In the manufacture of a photomask for manufacturing an integrated circuit of a semiconductor or other process photoresist film 8 coated onto the surface of hard plate 7 held by plate holder 6 on XY stage 5 is irradiated with light from light source 1 after arranging the reticle patterns of pattern holding part 2 on plate 7 by means of contracting lens 4 of step and repeat camera 3. At this time, film 8 is irradiated with light from light source 9 for measuring the thickness, and the reflected is received by photodetector 10. A change in the surface reflectance of plate 7 due to a change in the thickness of film 8 is indicated by the output voltage or electric current of detector 10, which is then amplified and compared to a predetermined standard thickness with a differential amplifier to control the shutter. Thus, the extent of exposure is controlled to prevent a pattern change due to a change in the thickness of film 8, and a mask of high accuracy is obtd.

Manufacture of photomask

Abstract: PURPOSE:To obtain a metal pattern of a desired size by coating the whole surface of a photomask consisting of a transparent substrate and a metal pattern of a width larger than the designed size on the substrate with a positive type photoresist film followed by exposure from the substrate side, development and side etching. CONSTITUTION:In the manufacture of a photomask for selective exposure for an integrated circuit, etc. pattern 2 made of metal such as Cr or metal oxide such as CrmOn is formed on transparent substrate 1 in a width larger than the designed size, and the whole is coated with photoresist film 3. Exposure from the substrate 1 side and development are then carried out to leave resist film 3 on pattern 2, and pattern 2 is side etched for a predetermined time using film 3 as a mask to obtain metal pattern 2 of the desired size. Thus, a corrected mask of high accuracy is obtd., and the photomask manufacturing yield is enhanced.

Photomask for integrated circuit

Abstract: PURPOSE:To enable an integrated circuit to be manufactured correctly and efficiently in an ordinary etching process by using at least one of a plurality of arranged mask patterns as an etching monitor chip forming pattern composed of a white pattern and a black pattern. CONSTITUTION:A plurality of mask patterns 2 for an integrated circuit are arranged longitudinally and laterally on glass surface 1 of a photomask, and one of patterns 2 is used as etching monitor chip forming mask pattern 3. When pattern 3 is magnified, in the square region corresponding to the area of one chip of the circuit rectangular white pattern 4 and rectangular black pattern 5 each having the length of one side of the region as the longitudinal size are combined in the form of a lattice. When a film part with two kinds of thickness is etched, white pattern 4' is partially superposed on the position of black pattern 5' of the etching monitor chip forming pattern of other photomask having the same combination for the circuit.

Manufacture of photomask

Abstract: PURPOSE:To obtain a photomask with high accuracy by making chips of different patterns about equal in plane size and forming two or more kinds of chip patterns on one reticle to make reticle exchange unnecessary in projection exposure and prevent pattern disagreement between chips CONSTITUTION:In a process of manufacturing photomask 11 having two or more kinds of chip patterns 12, 13, patterns 12, 13 are made equal in size, and reticles 14, 15 having 10-time size are formed on the same reticle 16 as one pair Reticle 16 is set in a photorepeater, and the feed extent of the repeater is regulated to size l of one chip pattern One chip pattern 15 is first shielded, and the other chip patterns 12 alone are successively projected on a photomask and exposed at step feed extent l Similar processing is then carried out to make reticle exchange unnecessary

Exposure of fine pattern

Abstract: PURPOSE:To process a fine pattern by performing offset exposure while using the same aligner and the same photomask CONSTITUTION:A photoresist 13 is applied on the SiO2 film 12 of an Si substrate 11 Positioning is made by an aligner after providing a pattern 14 with larger dimensions than desired ones to a photomask 15 The large-sized pattern 14 is printed by the first ultraviolet ray exposure Interference is completely eliminated because of its large size Next, the mask 15 is offsetted in a 45 deg direction for exposure In this case, the interference by diffraction is similarly and completely eliminated and a piled nonexposed part 16 becomes a desired fine pattern A fine pattern process is completed by eliminating the resist 13 at the part 16 and by etching the exposed SiO2 film 12 In this composition, pinholes caused by the dirt of the photomask and the projection of defects will also be eliminated and a fine pattern will be processed