Showing papers on "Photomask published in 1982"

Method and apparatus for redressing defective photomask

Abstract: A method and apparatus for repairing defect portions of a photomask. A complex material from which a light shading material can be deposited is applied over the photomask. A white (blank) defect region is irradiated with a continuous wave laser light beam projected in a slit-like light image to thereby convert the complex material into the shading material. After washing, a half-deposited portion formed in a peripheral portion of the light shading region is further deposited by a post-baking process. Those portions of the light shading film which depart from the desired mask pattern are removed together with black (solid) defect portion originally present in the photomask through irradiation with a pulse laser light beam. The pulse laser is constituted by a Dye-laser, while the continuous wave laser is constituted by an Ar-laser. A specific half-mirror which transmits therethrough Ar-laser light while reflecting Dye-laser light is displaceable provided. The white and the black defects are selectively centered on a same optical axis of an optical projection system including a slit and a condenser lens, whereby the white and the black defect portions are each removed through irradiation with the associated laser light projected thereto in a slit-like light image through the same optical projection system.

Method and apparatus for correcting transparent defects on a photomask

Abstract: A method and apparatus for correcting transparent defects on a photomask are disclosed. A metal-organic complex solution is applied to a transparent defect portion and its periphery on the photomask. The transparent defect portion is then exposed to a visible ray or ultraviolet ray to deposit a metal, a metal oxide or a composition thereof, while the light transmission quantity through the transparent defect portion is measured. After the measurement falls below a predetermined level relative to the quantity of the transmitted light at the start of exposure, the exposure is terminated to thereby complete the correction of the transparent defects.

Integrated circuit photomask

Abstract: The invention relstes to an integrated circuit photomask. The photomask it formed of a transparent dielectric substrate (1), such as glass and quartz based substrates, and has a conductive surface adjacent region (3), which is patterned with sequential overcoatings of a composite chrome oxide layer (5) and a chrome film (6). The mask comprises a combination of varied reflectivities to provide proper densities for the opaque areas of the mask.

Pattern detection system

Abstract: A pattern detection system for inspecting defects in fine or minute patterns such as photomask patterns at a fast speed is disclosed. The system comprises an illuminator, a device for moving objects with the patterns to be inspected with being illuminated by the illuminator, an optical system for imaging the objects, a scanner for scanning the objects in a direction intersected at a given angle with respect to direction of the objects moved by the moving device and arrays of photosensors arranged linearly in a direction perpendicular to that of images on the objects scanned by the scanner, on the surface of which the images are formed by the optical system and for producing respective outputs parallelly on the time basis.

Method of making CMOS device and contacts therein by enhanced oxidation of selectively implanted regions

Abstract: A CMOS process utilizes preferential oxidation of arsenic-doped regions and the reduced diffusivity of boron in arsenic-doped regions to eliminate photomask steps and to form self-aligned enhanced p+ and n+ contacts.

Methods of fabricating a photomask

Abstract: A photomask (30) used to form patterns on a resist coated semiconductor wafer is comprised of a transparent baseplate (31) having a thin metallic pattern (32) thereon; a transparent, planar coverplate (33) in intimate contact with the patterned baseplate (31) and an index matching fluid (34) interposed therebetween.

Manufacture of semiconductor device

Abstract: PURPOSE:To obtain a distinct pattern of a semiconductor device by a method wherein after grooves for evacuation of gas are formed on the scribing region of a semiconductor substrate, the photolithography process is performed CONSTITUTION:After a photo resist film 2' is formed on the semiconductor substrate 1, baking treatment is performed thereto, and after a photo mask 5 for formation of scribe lines is arranged thereon, exposure and development treatment are performed to form a pattern Then etching treatment is performed to form the grooves 6 Then by performing the photolithography process, the desired pattern is formed Accordingly because remaining gas between the mask 5 and the film 2' is evacuated through the grooves 6, adhesion between the film 2 and the photo mask 3 is unified, and definition of the pattern to be obtained by later exposure and development treatment is enhanced

Automatic photomask alignment system for projection printing

Abstract: An automatic photomask alignment system for projection printing includes a monochromatic light source, such as a laser, a series of diffraction patterns which are located on a semiconductor wafer in locations where alignments are to be made, at least one key which is located on a photomask with which the wafer is to be aligned, and a projection lens system. A light beam from the monochromatic light source is directed about the key on the photomask and through the projection lens system onto one of the diffraction patterns on the substrate to provide a pattern of light spots whose intensities at various locations are determined by the relative alignment of the key and the diffraction grating. A step and repeat mechanism is used to move the semiconductor wafer relative to the image of the photomask pattern which is projected onto the wafer while a feedback arrangement, which employs photocells and servo motors for aligning the locations where devices are to be formed on the substrate relative to the photomask, provides the alignment of the projected image with the proper locations for their formation.

Photomask and photomask substrate

Abstract: PURPOSE:To obtain a photomask for fabricating LSI having high precision and sperior durability, by forming a multilayer light-shielding film consisting of a thin Cr film layer and an upper layer containing Cr oxide and nitride on a transparent substrate, and forming a pattern on the multilayer. CONSTITUTION:A 50nm thick thin Cr layer 7 is formed on a transparent substrate 6 made of a soda lime glass or quartz glass or the like, and a mixed composition film in the range of CrXNYOZ, X=1, Y=0.1-1.4, Z=0.8-1.4 to form a photomask substrate, thus permitting both the film layers 7, 8 of this mask substrate to have the same etching speed in forming a pattern with an etching solution used in photolithography, electron beam lithography, etc., so to prevent defects of peeling of pent roofs formed from the edges of the layer 8, or the like, and to be good in resistance to chemicals, and a photomask high in precision and superior in durability to be obtained.

Electron beam exposure device

Abstract: PURPOSE:To complete fine correction once by positioning a pattern to be corrected while identifying the pattern with one electron microscope and switching the beam for exposure and exposing it. CONSTITUTION:Unnecessary pattern position is confirmed in advance for a photomask, a resist mask is coated, and is mounted on a base 7 in a sample chamber 6. The microscope is then evaculated, and an electron beam addcelerating voltage is set for observation by an acceleration controller 5. The photomask is confirmed through a window 4, the base 7 is moved to position the part to be corrected. Slit plates 2, 3 are controlled to form a rectangular beam, and the controller 5 is switched for exposure. Then, it is developed to remove unnecessary pattern. The defect of the pattern may be similarly corrected with the lift-off resist. According to this structure, the work can be simple and fine repair can be completed once.

Detecting Submicron Pattern Defects On Optical Photomasks Using An Enhanced El-3 Electron-Beam Lithography Tool

Abstract: This paper describes techniques to detect submicron pattern defects on optical photomasks with an enhanced direct-write, electron-beam lithographic tool. EL-3 is a third generation, shaped spot, electron-beam lithography tool developed by IBM to fabricate semiconductor devices and masks. This tool is being upgraded to provide 100% inspection of optical photomasks for submicron pattern defects, which are subsequently repaired. Fixed-size overlapped spots are stepped over the mask patterns while a signal derived from the back-scattered electrons is monitored to detect pattern defects. Inspection does not require pattern recognition because the inspection scan patterns are derived from the original design data. The inspection spot is square and larger than the minimum defect to be detected, to improve throughput. A new registration technique provides the beam-to-pattern overlay required to locate submicron defects. The 'guard banding" of inspection shapes prevents mask and system tolerances from producing false alarms that would occur should the spots be mispositioned such that they only partially covered a shape being inspected. A rescanning technique eliminates noise-related false alarms and significantly improves throughput. Data is accumulated during inspection and processed offline, as required for defect repair. EL-3 will detect 0.5 um pattern defects at throughputs compatible with mask manufacturing.© (1982) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Method of evaluating measure precision of patterns and photomask therefor

Abstract: A method for evaluating the measure precision of patterns such as photoresist and etched ones, and a photomask therefor. The photomask according to the present invention has a mask pattern corresponding to a pattern desired to be formed in a substrate, and also has a measure precision evaluating pattern formed at an area different from where the mask pattern is present. The measure precision evaluating pattern comprises a first measure precision evaluating pattern which has a plurality of pairs of pattern elements opposite to each other with a predetermined distance interposed therebetween, and a second measure precision evaluating pattern which has a plurality of pairs of pattern elements overlapped each other in a predetermined measure and arranged opposite to each other to form a constricted portion. The distance or the measure of overlapped area between paired pattern elements is varied with every pair of pattern elements. This mask pattern is transcribed onto the substrate and a pair of pattern elements contacting each other without overlapping is found from the transcribed pattern. Dimensional change is found from the distance or the measure of overlapped area between the pair of photomask pattern elements corresponding to that pair of pattern elements which has been found from the transcribed pattern.

Flexible non-extensible hinge for photomask assembly

Abstract: Hinged glass photomask assemblies for photolithographic processes are disclosed wherein a flexible polymeric hinge is used in combination with a flexible, non-extensible binding strip which prevents lateral movement of the glass plates thereby providing for repeated use of the phototool without the use of registration systems such as alignment pin assemblies.

System for encapsulation of semiconductor chips

Abstract: A system for encapsulating semiconductor chips, such as chips carrying chemical sensitive field-effect devices, includes lamination of a sheet of dry film photoresist material onto the surface of the chip, placement of a photomask over the chip in a predetermined alignment, and then exposure of the photomask to light so that light passes through certain light-transmitting portions of the mask onto the chip. The photoresist material is then developed to remove the material from over the gate regions of each of the field-effect devices to define windows in the material through which the gate regions are exposed. Chemical sensitive membrane systems may then be applied to the windows of the devices to cover the gate regions.

Semiconductor measurement technology: Interlaboratory study on linewidth measurements for antireflective chromium photomasks

Abstract: and

Manufacturing and inspecting method for photomask

Abstract: PURPOSE:To improve the quality of a photomask by detecting a defective due to a reticle pattern accurately by forming the photomask by contracting and arraying the 1st and 2nd reticles, havng the same pattern, on a har plate coated with photoresist CONSTITUTION:A photomask 20 is exposed to an A chip 1 by using the 1st reticle pattern and then exposed to a B chip 2 by using the 2nd reticle pattern The 1st and 2nd reticle patterns have exactly the same pattern, so the defective of the photomask 20 is detected by optically comparing the A chip 1 and B chip 2 arrayed in the 1st and 2nd reticle patterns

X-Ray Mask Fabrication

Abstract: X-ray lithography is composed of three elements, the alignment machine with an X-ray source, X-ray photomasks, and X-ray resist. This paper describes the processes used to manufacture boron-nitride X-ray masks and some of the results using those masks.

Photomask and its preparation

Abstract: PURPOSE:To reduce diffracted light at the end of a light shielded part and slantly incident light and to obtain a photomask capable of forming micropatterns faithful to the mask, by providing a transparent flat relief adjaeant to a light shielding part. CONSTITUTION:A light shielding film 22 consisting of chromium or its oxide, or the like is uniformly formed on a glass substrate 21, and a photosensitive resin pattern 23 is formed on this film 22 by using the ultraviolet lithography. At that time, the end part 23' of the pattern 23 is caused to have 65-90 deg. end inclination angle to the substrate 21. The film 22 is etched using the pattern 23 as a mask to form the pattern of the light shielding part 22', and then, the whole face is provided with a silicon dioxide film 24. After only the silicon dioxide film 24' attached to the end 23' of the pattern 23 has been selectively removed using a hydrofluoric acid buffer solution, the resin pattern 23 is removed together with the film 24 on this pattern 23, thus permitting a photomask 25 consisting of the light shielding part 22' and the silicon dioxide film 24'' (a transparent flat relief) adjacent to this to be obtained.

Registration blocks for a photomask assembly

Abstract: An alignment system for providing simple, efficient, repeatable and precise registration of a pair of plates in a photomask assembly for use in photolithographic imaging processes is disclosed, wherein registration blocks are attached to the edges of one plate and block stops are attached to the other plate in appropriate positions to engage said registration blocks when the plates are brought into parallel facing relationship in contact with a substrate to be processed.

Preparation of semiconductor device

Abstract: PURPOSE:To prevent a defect in a mask pattern without permitting a photosensitive resin to remain on the outside edge of a wafer with a certain width by a method wherein the wafer coated with a positive type photosensitive resin and a photomask on which a mask pattern region smaller than the wafer has been formed are placed one above another and exposed to rays. CONSTITUTION:The surfaces of a wafer 31 is coated with a positive type photoresist 32. A mask pattern region 35 smaller than the main surface of the wafer 31 but similar to the figure of the latter is formed on a photomask 33. The photomask 33 and the wafer 31 are set against each other, before being exposed to ultraviolet rays 34. The outside edge of the wafer 31 in several mm. width is exposed to the rays through a transparent member 36 of the photomask 33. By so doing, when the wafer 31 is put into grooves 42 of a cassete 41, the photoresist 32 on the wafer does not make contact with the cassette, thus preventing the occcurrence of defects in the pattern such as cracks and exfoliation.

Yield Improvement With Pellicalised Masks In Projection Printing Technology

Abstract: Photomask limited yields in LSI and VLSI processes are examined in this paper. Mask defects are classified into two catagories i.e., soft and hard mask defects. Theoretical modelling indicates a substantial yield improvement with pellicle protected masks. In 1:1 projection technology soft mask defects are the predominent cause of mask limited yield. Use of pellicles eliminates the effect of soft defects up to 100 microns in size, does not cause a degradation of image quality or dimensional control, prolongs mask life, and saves considerable labour and cost in maintaining high quality masks. Pellicle mounting, inspection, and handling techniques used are described. Very large die with 3 micron, NMOS, Si-gate technology are used to determine the actual yield improvement. Lots were processed using identical sets of masks of which one set was pellicle protected. Defect density at each process step and final probe yield are statistically analysed to show the individual contributions of hard mask defects, soft mask defects, and random process defects to the overall device yield. Actual yield increase data is presented. This pellicle technology is directly applicable to 10:1 stepping exposure systems where high soft mask defect density could be a more severe problem than in 1:1 projection systems.

Method and apparatus for correcting defects on a photomask

Abstract: A method and apparatus for repairing defect portions of a photomask. A complex material (70) from which a light shading material can be deposited is applied over the photomask (5). A white (blank) defect region (7) is irradiated with a continuous wave laser light beam projected in a slit-like light image to thereby convert the complex material into the shading material. After washing, a half-deposited portion (73) formed in a peripheral portion of the light shading region is further deposited by a post-baking process. Those portions of the light shading film which depart from the desired mask pattern are removed together with black (solid) defect portion (6) originally present in the photomask through irradiation with a pulse laser light beam (47). The pulse laser is constituted by a Dye-laser, while the continuous wave laser is constituted by an Ar-laser. A specific half-mirror (39) which transmits therethrough Ar-laser light while reflecting Dye-laser light is displaceably provided. The white and the black defects are selectively centered on a same optical axis of an optical projection system including a slit (42) and a condenser lens (43), whereby the white and the black defect portions are each removed through irradiation with the associated laser light projected thereto in a slit-like light image through the same optical projection system.

Automatic Mask And Reticle Inspection System

Abstract: Automatic photomask inspection systems have been commercially available for a number of years. KLA Instruments has manufactured systems which utilize die-comparison to detect photomask defects. This paper describes some of the technical modifications and enhancements which augment the basic photomask inspection capability of a die-comparison system by adding the capability to inspect a single-die reticle against the data base which generated it.© (1982) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Forming method for resist pattern

Abstract: PURPOSE:To enable the formation of an extremely small resist pattern by interposing and exposing a fluidic substance transparent for ultraviolet or far ultraviolet ray between a resist film and a photomask in the step of adhering and exposing the resist film. CONSTITUTION:Water 25 is, for example, adhered as a fluid substance to the surface of a photomask 14 formed with light shielding pattern 13, and the photomask 14 is intimately contacted with a resist film 12 coated on a semiconductor wafer 11. After the film 12 is then exposed, for example, by ultraviolet rays, it is developed, and a resist pattern is formed. The fluid substance to be interposed between the film 12 and the photomask 14 is transparent for the exposing light and has higher than 1.3 of refractive index. Thus, it can improve the decrease in the yield of the small pattern caused by the improper contact, and can form an extremely small resist pattern.

Method for determining photomask alignment

Abstract: This describes a method for electrically evaluating the overlay error of a photolithographic tool. In this process a reusable substrate (10) bearing a fixed reference mark (15) has a photolithographic tool defined metal liftoff pattern (17) formed thereon to provide a pair of conductive lines (20a, 20b) by measuring the relative resistance of the lines with respect to one another the alignment of the tool defined pattern with regard to the reference mark (15) may be determined and thus the overlay error of the tool established.

Photomask and method of testing it

Abstract: A photomask (1) for use in the manufacture of a semiconductor device comprises a pattern (P1, P2) to be tested and for use in forming the semiconductor device and an additional synchronisation pattern (S1 to S8). The synchronisation pattern is used to obtain a synchronisation pulse (E1, Ez, Es, E6) during scanning of the photomask (1) for synchronising a scanning signal (S9) obtained from the pattern (P1, P2) to be tested with a reference signal (S10) based on reference pattern data stored on a magnetic tape (7).

X-Ray Lithography: Fabrication Of Masks And Very Large Scale Integrated (VLSI) Devices

Abstract: Recent advances in x-ray lithography show that accurate, low defect replication of submicron features is becoming a reality. However, before x-ray lithography can be implemented in production several difficult issues must be resolved. In particular, x-ray masks must be fabricated on thin membranes with low defect density and high dimensional stability. The Intel Magnetics one megabit bubble memory is an ideal initial evaluation device because of the high resolution required (1.2 μm minimum feature size) together with its defect and alignment tolerance. Data is presented on one megabit bubble memories fabricated with the trilevel resist scheme using the commercially available resist Sel-N, Type A (exposure time is typically 2 minutes with the Perkin-Elmer 10kW tungsten x-ray exposure system). Distortion and defect data is presented showing our learning experience in fabricating x-ray masks with MEBES. Masks with sufficient stability to start LSI silicon device evaluation have been available for more than a year, masks with sufficiently low defect density to start evaluation of such devices are projected to be available in 1982. Radiation sensitive LSI devices have been exposed to lithographic levels of x-ray flux while undergoing otherwise conventional fabrication. Test data showing no performance degradation in these devices is reviewed.© (1982) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Preparation of photomask

Abstract: PURPOSE:To prevent defects of a pattern due to dust in preparation of a photomask by exposure to electron beams, by coating a resin film requiring a solvent different from a solvent of a resist film on the resist film. CONSTITUTION:A light-shielding film 2 of chromium or the like, an electron beam resist film 3, such as polyglycidyl methacrylate, and a resin layer 4 such as PVA using a solvent different from that of said resist film 3, are formed on a mask substrate 1. This resist film 3 is exposed to electron beams through the resin layer 4 in vacuum, cleared of the resin film 4 in normal pressure, and the resist film is developed, thus permitting dust introduced and attached dust upon restoring the pressure to the normal to be removed in a resin film 4 removal step, and a photomask free from defects to be obtained.

Use Of The National Bureau Of Standards (NBS) Antireflective (AR)-Chromium Optical Linewidth Standard For Measurements On Other Types Of Chromium Photomasks

Abstract: Both antireflective (AR)-chromium and bright-chromium photomasks are currently used in the production of integrated circuits. Differences in the optical transmittance and reflectance of these photomasks can significantly change the line-image threshold required for accurate edge detection in optical microscope linewidth measurements. The suitability of using a calibration curve based on an AR-chromium optical linewidth-measurement standard (SRM 474) from the National Bureau of Standards (NBS) to correct linewidth measurements on other types of photomasks is discussed. Linewidths on each of three chromium photomasks of different chromium thicknesses were measured on four different types of optical microscope linewidth measurement systems. These measurements were corrected using an SRM 474 and compared with measurements made on the NBS optical linewidth calibration system. For the two bright-chromium specimens with low transmittance, the residual differences between the corrected values and the NBS values as measured on the NBS calibration system are generally less than ±0.05 μm for three of the measurement systems. For the see-through AR-chromium photomask with a higher transmittance, the calibration curve does not correct all systematic errors greater than ±0.05 μm. These results support theoretical studies showing that the degree of correction for systematic linewidth errors varies with the transmittance of the chromium photomask being measured and with the measurement system.

Method for construction of pattern

Abstract: PURPOSE:To obtain a photomask of good accuracy by constructing patterns for a photomask using photoresist in an inert atmosphere. CONSTITUTION:After the inside of a sealed vessel 10 is evacuated to a vacuum through a vacuum exhausting valve 11, gaseous N2 is sucked through an N2 purging valve 12, whereby an inert atmosphere is created therein. The cassette 7 on the supply side of an automatic carry-in and out device, a photomask 4 using the emulsion in this cassette 7, a passage 9 for the photomask 4, a movable stage 6, the photomask 4 on the stage 6, a cassette 8 on the receiving side, and the photomask 4 in this cassette 8 exist in the inert atmosphere, and therefore, the construction of patterns is accomplished in the inert atmosphere. Since the working atmosphere is an inert atmosphere, the reaction by which the sensitivity specks produced in exposure parts are changed to silver halide is suppressed, and the degradation in dimensional accuracy owing to insufficient density after development is obviated.