Showing papers on "Photomask published in 2000"

Prototyping of Masks, Masters, and Stamps/Molds for Soft Lithography Using an Office Printer and Photographic Reduction

Abstract: This paper describes a practical method for the fabrication of photomasks, masters, and stamps/molds used in soft lithography that minimizes the need for specialized equipment. In this method, CAD files are first printed onto paper using an office printer with resolution of 600 dots/in. Photographic reduction of these printed patterns transfers the images onto 35-mm film or microfiche. These photographic films can be used, after development, as photomasks in 1:1 contact photolithography. With the resulting photoresist masters, it is straightforward to fabricate poly(dimethylsiloxane) (PDMS) stamps/molds for soft lithography. This process can generate microstructures as small as 15 microm; the overall time to go from CAD file to PDMS stamp is 4-24 h. Although access to equipment-spin coater and ultraviolet exposure tool-normally found in the clean room is still required, the cost of the photomask itself is small, and the time required to go from concept to device is short. A comparison between this method and all other methods that generate film-type photomasks has been performed using test patterns of lines, squares, and circles. Three microstructures have also been fabricated to demonstrate the utility of this method in practical applications.

Novel alignment system for imprint lithography

Abstract: A novel alignment system for imprint lithography in the deep sub-hundred nanometer realm is proposed. The new system is inherently more precise than the alignment systems used in conventional projection lithography because alignment marks on an imprint mold (the functional equivalent of a photomask in projection lithography) are directly compared to alignment marks on a wafer with no intermediate optics or reference points. If the measured misalignment is so severe that all marks cannot be brought into registration simultaneously by the usual x–y translations and rotations, the mold is deliberately deformed with a system of piezoelectric actuators in such a way that its induced distortions precisely match those on the wafer and all of the alignment marks at each chip site can be pulled into registration simultaneously. Finite-element analysis indicates that using actuators to distort the mold is superior to distorting the wafer.

Phase shift mask blank, phase shift mask, and method for manufacturing the same

Abstract: PROBLEM TO BE SOLVED: To provide a halftone type phase shift mask on which a fine photomask pattern is formed with high accuracy, and to provide a mask blank for producing the above mask. SOLUTION: A semitransparent film 15 having a predetermined phase shift and transmittance to exposure light and a light shielding film 12 placed on the semitransparent film 15 are disposed on one principal face of a transparent substrate 11 such as quartz as a photomask substrate. The light shielding film 12 is surely a so-called "light shielding film" but it can also act as an antireflection film. The semitransparent film 15 is a halftone phase shift layer comprising a halftone material containing both of silicon (Si) and molybdenum (Mo) as an absorbent material. In order to use the halftone phase shift mask blank for producing a mask for ArF exposure, the film thickness and composition of the light shielding film 12 are selected to obtain the optical density OD of the film in the range of 1.2 to 2.3 with respect to light at 193 or 248 nm wavelength. COPYRIGHT: (C)2007,JPO&INPIT

Halftone phase shift photomask and blanks for the same

Abstract: PROBLEM TO BE SOLVED: To provide a halftone phase shift photomask using a molybdenum silicide-base halftone phase shift film material and having a structure with an enhanced etching selectivity ratio to a quartz substrate while retaining superior workability of the molybdenum silicide-base material and chemical stability after working. SOLUTION: A blank for the halftone phase shift photomask has a halftone phase shift layer on a transparent substrate and the halftone phase shift layer is formed from a multilayer film having at least a layer based on molybdenum silicide and containing oxygen and/or nitrogen and comprising two or more layers. A layer based on chromium, tantalum or a chromium-tantalum alloy is included in the multilayer film and this layer is disposed nearer the transparent substrate than the layer based on molybdenum silicide and containing oxygen and/or nitrogen. COPYRIGHT: (C)2002,JPO

Method of exposure, photomask, method of production of photomask, microdevice, and method of production of microdevice

Abstract: A method of exposure projecting and exposing a pattern formed on a mask on to a photosensitive substrate through a projection optical system, comprising the steps of measuring a position of an image projected by said projection optical system; and projecting and exposing said pattern of the mask in a state with imaging characteristics corrected to reduce an amount of offset of a position of said projected image from an ideal position.

Method of expanding process window for the double exposure technique with alt-PSMs

Abstract: For the fine patterning of gate layers on embedded DRAM is logic devices with a design rule of 0.13 micrometers and below, we have optimized the double exposure technique with an alternative phase shifting mask using KrF excimer laser exposure. Based on the study over lithography process latitude with respect to exposure-defocus window, overlay margin and mask fabrication feasibility, we have adopted a process as that patterns in logic circuits are delineated by the combination of alt-PSM and a trim mask made of Cr shielding patterns on an attenuated phase shifting mask, while patterns in DRAM cells are delineated by the latter att-PSM exposure only. With considering a mask error enhancement factor, optical condition and optical proximity effect correction for the alt-PSM and trim mask are also optimized, then, 0.13 micrometers embedded DRAM in logic patterns have been fabricated with a sufficient common lithography process window by the KrF excimer laser exposure.

Manufacture of semiconductor device

Abstract: PROBLEM TO BE SOLVED: To form a polycrystalline TFT with gate line width of about 0.5 μm on a large-area substrate. SOLUTION: A thin film 22 is film-formed on a glass substrate 21 which is coated with a photoresist 23 to form a thin-film laminate 36. The photoresist 23 is directly irradiated with ultraviolet ray laser beams 24 to form an etching mask 23a. Thus, problems such as alignment precision of the photomask, effect of parallelism and a step precision are settled. Further, with the use of ultraviolet ray laser beams, the resolution in line width is about 0.5 μm level, allowing a fine polycrystalline TFT with high current driving capacity to be formed on a large-area substrate.

Synthetic quartz glass substrate for photomask and making method

Abstract: A synthetic quartz glass substrate is prepared by annealing a synthetic quartz glass member having a higher hydroxyl content in a peripheral portion than in a central portion, machining off the peripheral portion of the member, slicing the member into a plate shaped substrate, chamfering and etching the substrate. The synthetic quartz glass substrate has a minimized birefringence and is suited for use as a photomask in photolithography.

Direct write all-glass photomask blanks

Abstract: A narrowly defined range of zinc silicate glass compositions is found to produce High Energy Beam Sensitive-glass (HEBS-glass) that possesses the essential properties of a true gray level mask which is necessary for the fabrication of general three dimensional microstructures with one optical exposure in a conventional photolithographic process. The essential properties are (1) A mask pattern or image is grainiless even when observed under optical microscope at 1000× or at higher magnifications. (2) The HEBS-glass is insensitive and/or inert to photons in the spectral ranges employed in photolithographic processes, and is also insensitive and/or inert to visible spectral range of light so that a HEBS-glass mask blank and a HEBS-glass mask are permanently stable under room lighting conditions. (3) The HEBS-glass is sufficiently sensitive to electron beam exposure, so that the cost of making a mask using an e-beam writer is affordable for many applications. (4) the e-beam induced optical density is a unique function of, and is a very reproducible function of electron dosages for one or more combinations of the parameters of an e-beam writer. The parameters of e-beam writers include beam accelerations voltage, beam current, beam spot size and addressing grid size.

Liquid crystal display device with particular TFT structure and method of manufacturing the same

Abstract: In a liquid crystal display device of an IPS system, to realize reduction of manufacturing cost and improvement of yield by decreasing the number of steps for manufacturing a TFT. The present invention adopts a channel etch type bottom gate TFT structure, and is characterized in that patterning of a source region 119 and a drain region 120 and patterning of a source wiring 121 and a pixel electrode 122 are carried out by the same photomask.

Method for incorporating sub resolution assist features in a photomask layout

Abstract: A method for developing a photomask layout by which an electrical circuit is imaged that includes introducing sub resolution assist features into a photomask layout by (1) sorting selected details of the main electrical circuit undergoing enhancement according to a predetermined order of importance of enhancement of the selected details of the main electrical circuit to the overall performance of the main electrical circuit, (2) establishing a prioritization for sub resolution assist features associated with the selected details of the main electrical circuit based on the predetermined order of importance of the selected details of the main electrical circuit with which the sub resolution assist features are associated, and (3) incorporating sub resolution assist features in the photomask layout in accordance with the established prioritization of the sub resolution features.

Patterning method of thin film, tft array substrate using the patterning method, and manufacturing method of the tft array substrate

Abstract: PROBLEM TO BE SOLVED: To prevent difference in the thickness of a half-tone resist due to the presence or absence of a base film, and to carry out accurate patterning. SOLUTION: In a photomask 14a for exposing the resist to light, a transmitting section C, a shielding section A, and two kinds of translucent sections B1 and B2 having a different quantity of light transmitted are provided. A region with the foundation film 5 is set to the translucent section B1 having a small quantity of light, and a region without the base film is set to the translucent section B2 having a large quantity of light. The amount of exposure when the exposure is made is adjusted for achieving the uniform half tone resist.

Optimizing edge topography of alternating phase-shift masks using rigorous mask modeling

Abstract: This paper describes mask topography effects of alternating phase shift masks for DUV lithography. First two options to achieve intensity balancing are discussed. Global phase errors of +/- 10 degrees cause a CD change of 3 nm and 8 nm CD placement errors. The CD placement appears to be the parameter affected most by phase errors. A sloped quartz edge with an angle of 3 degrees causes a CD change of 10 nm. The CD sensitivity on local phase errors, i.e. quartz bumps or holes was also studied. The critical defect size of a quartz bump was seen to be 150 nm for 150 nm technology. For the investigation the recently developed topography simulator T-mask was used. The simulator was first checked against analytical tests and experimental results.

Photolithography method, photolithography mask blanks, and method of making

Abstract: The invention provides optical projection lithography methods, photolithography photomasks, and optical photolithography mask blanks for use in optical photolithography systems utilizing deep ultraviolet light (DUV) wavelengths below 300 nm, such as DUV projection lithography systems utilizing wavelengths in the 248 nm region and the 193 nm region. The invention provides improved production of lithography patterns by inhibiting polarization mode dispersion of lithography light utilizing low birefringence mask blanks and photomasks.

Method and apparatus for repairing an alternating phase shift mask

Abstract: A method and apparatus for correcting phase shift defects in a photomask is provided by scanning the photomask for the defect and determining locations of at least one defect. Following the determination of the location of a defect, the defect is three-dimensionally analyzed producing three-dimensional results. Utilizing the three-dimensional results, a focus ion beam (FIB) is directed onto the defect to eliminate the defect. The FIB is controlled by an etch map which is generated based on the three-dimensional results. To provide further precision to the repairing of the photomask, test patterns of the FIB are generated and three-dimensionally analyzed. The three-dimensional test pattern results are further utilized in generating the etch map to provide greater control to the FIB.

Pattern forming method and light exposure apparatus

Abstract: Disclosed is a pattern forming method, in which a mask blank for preparation of a photomask is exposed in a desired pattern to form a mask pattern on the mask blank. Position measuring marks are formed on the diagonally facing corners of a main surface of the mask blank to detect a defect on the main surface of the mask blank. The relative positions of the detected defect and the mask pattern that is to be formed on the mask blank are compared, and the pattern position is selected such that the defect overlaps with the pattern. Then, the position measuring marks are measured to calculate the exposure position, and exposure treatment is applied to the selected position.

Photomask, aberration correction plate, exposure apparatus, and process of production of microdevice

Abstract: A photomask including a substrate comprised of fluorite (calcium fluoride (CaF 2 )) and protective films comprised of chrome (Cr), chromium oxide (Cro), silicon oxide (SiO 2 or SiO), etc. and formed at regions, other than the pattern region where the pattern to be transferred is formed, which contact other members when transporting the photomask or using it for exposure.

Photomask for projection exposure and for projection exposure method using the photomask

Abstract: PROBLEM TO BE SOLVED: To control the complex amplitude transmittance by a single method and to realize a super resolution method including phase modulation which is used for a phase shift mask method by modulating the complex amplitude. SOLUTION: This photomask consists of a photomask substrate 1 and a grating layer 4 formed on at least a part of the photomask substrate 1. The grating layer 4 consists of a periodical structure 5 having a grating pitch T smaller than the wavelength of the light used for projection exposure. At least one medium constituting the grating layer 4 consists of an absorptive medium 2 which partly absorbs the light during projection exposure. In the periodical structure 5, the thickness of the grating layer 4 is almost constant and the absorptive medium 2 has a square cross section. COPYRIGHT: (C)2001,JPO

Blanks for photomask with area code, photomask with area code and method for producing photomask

Abstract: PROBLEM TO BE SOLVED: To provide a control method capable of properly controlling the substrates of blanks or blanks with a disposed resist (resist coated blanks) in connection with processing in a continuous or intermittent manner from the stage of the blanks to the stage of manufactured photomasks in the manufacture of photomasks. SOLUTION: The blanks for a photomask with an optionally disposed resist for manufacturing each photomask for forming a semiconductor circuit such as IC or LSI have an optical reading type area code (two-dimensional ID code) disposed on an edge face or the rear face of each glass substrate. The area code is formed with a laser marker on a metallic film formed on the edge face or the rear face of the glass substrate of the blanks for photomask.

Overview of the ion projection lithography European MEDEA and international program

Abstract: Ion Projection Lithography (IPL) follows the same principle as optical wafer steppers when using hydrogen or helium ions for the reduction printing of stencil mask patterns to wafer substrates: (1) DUV resists can be used with ion beam exposure; (2) well established optical wafer alignment techniques are used; (3) the mask is stable during exposure. IPL is the only NGL technique where the mask is not scanned during exposure. Because of the very small particle wavelength (5 * 10-5 nm for 100 keV He+ ions there is the possibility of using electrostatic ion-optics with very small numerical aperture (NA approximately equals 10-5). The ion-optics is based on aluminum lens electrode and standard insulator materials. Mechanical tolerances on lens electrode manufacturing and adjustment are in the micrometer range because of in-situ electronic column fine adjustment possibilities. Wafer stage movements with micrometer precision is sufficient through feedback from precise laser interferometer stage position measurements to electronic image placement of the ion image projected to the wafer with on-line 'pattern lock' control. As part of the MEDEA project an IPL process development tool (PDT) is being integrated by IMS with the target to achieve 50 nm resolution within a 12.5 mm exposure field. The IPL production stepper will be based on a similar but more compact ion-optical column, exposing large (e.g. 25 mm) chip fields by stitching of 12.5 mm fields. A 300 mm wafer throughput of 30 WPH is feasible also for the 50 nm node. IPL has the potential of achieving the lowest NGL cost of ownership with the longest multi-generational life time. The practical resolution limit of the IPL technique is below 35 nm.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Halftone phase shift photomask and blanks for halftone phase shift photomask

Abstract: PURPOSE: A halftone phase shift photomask and blanks for a halftone phase shift photomask are provided, to allow the transmittance and reflectivity to be controlled by the combination of layer thickness and to simplify the structure of the photomask and the blanks. CONSTITUTION: The halftone phase shift photomask comprises a transparent region and a semitransparent region comprising the chromium compound formed by physical vapor growth method on a transparent substrate. The transmittance of the semitransparent region is 3-35 % when the transmittance of the transparent region is defined as 100 %, and the semitransparent region shifts the phase of the exposing wavelength to the transparent region. Preferably the chromium compound comprises chromium, oxygen or chromium, oxygen, nitrogen or chromium, oxygen, carbon or chromium, oxygen, nitrogen, carbon; and the semitransparent region layer is a monolayer or a multilayer.

Method of manufacturing schottky gate transistor utilizing alignment techniques with multiple photoresist layers

Abstract: The specification describes a photolithography process using multiple exposures to form z-dimension patterns. Multiple exposures at different thickness levels are made using photomasks aligned with a latent image of alignment marks formed during the first exposure. The latent image is visible to the alignment system of commercial steppers.

Photomask, manufacturing method thereof, and semiconductor device

Abstract: A corrected irradiation region ( 14 ) to be irradiated with a laser light under given output conditions to remove an opaque extension defect ( 13 ) is set to include: {circumflex over (1)} an irradiation region ( 14 A) containing the opaque extension defect ( 13 ) and having widths w 1 and w 2 and {circumflex over (2)} a pattern repaired region ( 14 B) having the width w 2 and extending in the negative direction in a first direction D 1 by the absolute value of a quantity of bias offset of repairing Δw from the connection between the opaque extension defect ( 13 ) and the pattern edge ( 12 E). The quantity of correction offset Δw is set so that the dimensional variation rate of the resist pattern transferred falls within a range permitted for the device quality. Part of the pattern edge ( 12 E) is missing by the width |Δw| after the irradiation of laser light. When the design pattern dimension as dimensional value on the photomask is reduced to about 1 μm, for example, it is thus possible to alleviate the adverse effect of the dimensional variation of the resist pattern on the device quality that is caused by a reduction in transmittance in the repaired defect portion.

Method for manufacturing semiconductor integrated circuit device, optical mask used therefor, method for manufacturing the same, and mask blanks used therefor

Abstract: In order to suppress or prevent the occurrence of foreign matter in the manufacture of a semiconductor integrated circuit device by the use of a photo mask constituted in such a manner that a resist film is made to function as a light screening film, inspection or exposure treatment is carried out, when the photo mask 1 PA 1 has been mounted on a predetermined apparatus such as, e.g., an inspection equipment or aligner, in the state in which a mounting portion 2 of the predetermined apparatus is contacted with that region of a major surface of a mask substrate 1 a of the photo mask 1 PA 1 in which a light shielding pattern 1 b and a mask pattern 1 mr , each formed of a resist film, on the major surface of the mask substrate 1 a do not exist.

Fabrication of graphite masks for deep and ultradeep x-ray lithography

Abstract: Masks made from graphite stock material have been demonstrated as a cost-effective and reliable method of fabricating X-ray masks for deep and ultra-deep x-ray lithography (DXRL and UDXRL, respectively). The focus on this research effort was to fabricate masks that were compatible with the requirements for deep and ultra deep X-ray lithography by using UV optical lithography and gold electroforming. The major focus was on the uniform application of a thick resist on a porous graphite substrate. After patterning the resist, gold deposition was performed to build up the absorber structures using pulsed- electroplating. In this paper we will report on the current status of the mask fabrication process and present some preliminary exposure results.

End of thresholds: subwavelength optical linewidth measurement using the flux-area technique

Abstract: The patented Flux-Area technique of metrology with optical images has been proven to provide accurately and repeatable measurements of defect sizes as small as 0.08 (mu) , and is in use in 12 leading edge mask shops and wafer fabs around the world. This paper describes the extension of this technique for linewidth measurement and the result of test on photomasks, using lines as narrow as 0.25 micrometers . Linewidths were measured with SEM and optical images analyzed with the Flux-Area technique. Results show that the new technique provides linear measurements on even the smallest lines, using visible as well as UV illumination. This technique promises to allow mask makers to continue measuring their masks optically, even as linewidths shrink much smaller than the optical wavelengths used in the measurement. Further, this technique allows older visible light system to be used for measuring even DUV masks. Finally, this technique does not require thresholds: it only requires an image and that the optical magnification be known. The technique simply measures the amount of light absorbed by a feature, the fundamental optical quality of any photomask feature.

Blanks for photomask and photomask

Abstract: PROBLEM TO BE SOLVED: To form a strain-free precise pattern by reducing film stress and suppressing the warpage of a substrate before and after film deposition. SOLUTION: In the objective blanks for a photomask with at least one light shielding film and at least one antireflection film on a transparent substrate, all of the light shielding film and the antireflection film are formed from a CrCO layer, a CrCON layer or a composite layer obtained by combining a CrCO layer and a CrCON layer.

Proximity exposure method and proximity aligner

Abstract: PROBLEM TO BE SOLVED: To perform proximity exposure to a glass base plate whose size is larger than a photomask at high speed by raising an exposure chuck with respect to the photomask and performing exposure processing to a new glass base plate. SOLUTION: When a carrying-in arm 61 is retreated, a three-point contact type tilt driving motor is driven to raise the glass base plate 1 to a proximity gap controlling position. A proximity gap is controlled and accurate alignment is performed. At the point of time when the accurate alignment is finished, first exposure is performed to the right half of the plate 1. After finishing the exposure, the Z-axis of a base plate alignment stage 11 is driven to lower the plate 1, the exposure chuck 2 and a step table 41 from the photomask 3 by a very short distance. Then, the table 41 is moved stepwise to an unloader unit side (+X direction) so as to position the left half of the plate 1 and the photomask 3, then second exposure is performed to the left half of the plate 1.

Phase shift photomask blank, phase shift photomask, and manufacturing method of semiconductor device

Abstract: PROBLEM TO BE SOLVED: To provide the phase shift photomask, capable of the satisfied examination, which can obtain sufficient transmitivity for the exposure wavelength of the sort wavelength to be used and has the suitable transmitvity also for the defective examination wavelength, and to provide phase shift photomask blanks for manufacturing the mask and the manufacturing method of the semiconductor device using this mask. SOLUTION: In a attenuated type phase shift film consisting of two layers, the refractive index of the upper film is set smaller than the refractive index of the sublayer film, the transmitivity in the exposure wavelength is set high, and in the attenuated type phase shift film consisting of three layers, the refractive index of the film of the intermediate layer is set smaller than the refractive index of the upper layer and the sublayer film, and the transmitivity in the defective examination wavelength is lowered. In the attenuated type phase shift film consisting of three-layers or more, the refractive index of the film of the uppermost layer is set smaller than the refractive index of the sublayer direct film, and the trasmitivity in the exposure wavelength is set high. COPYRIGHT: (C)2001,JPO

System, method and photomask for compensating aberrations in a photolithography patterning system

Abstract: A method, system, and photomask is used to compensate for aberrations in a photolithographic patterning system, and to improve the overall process control of substrate features formed by a compensated photolithography mask. The photolithography mask is derived such that substrate features are corrected to compensate for photolithography patterning system aberrations. Test features contained on a photomask can be printed in a photoresist located on an upper surface of a semiconductor substrate by a photolithography patterning system. Images of the test patterns are evaluated by a metrology tool, for example, measured by a scanning electron microscope, and then assessed to characterize the system aberrations. Characterization of the aberrations indicates the size and location of an aberration-affected area, and the aberrations' effects on various types of design features. The design features which would be affected by the aberrations are modified by changing their size(s) and/or shape(s) to form mask features configured to compensate for the aberration-induced distortions.