Source: http://www.google.com/patents/US5235400?dq=6948823
Timestamp: 2013-12-21 12:58:51
Document Index: 579647852

Matched Legal Cases: ['art 24', 'art 24', 'art 24', 'art 24', 'art 24', 'in fine']

Patent US5235400 - Method of and apparatus for detecting defect on photomask - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsA method of and an apparatus for detecting a defect on a phase-shifting mask for use in a projection aligner in which either or both of respective intensities of transmitted and reflected light beams from the mask illuminated with light are used for detecting a defect on the mask....http://www.google.com/patents/US5235400?utm_source=gb-gplus-sharePatent US5235400 - Method of and apparatus for detecting defect on photomaskAdvanced Patent SearchPublication numberUS5235400 APublication typeGrantApplication numberUS 07/418,525Publication dateAug 10, 1993Filing dateOct 10, 1989Priority dateOct 12, 1988Fee statusLapsedPublication number07418525, 418525, US 5235400 A, US 5235400A, US-A-5235400, US5235400 A, US5235400AInventorsHiroshi Fukuda, Norio Hasegawa, Toshiei Kurosaki, Toshihiko Tanaka, Tsuneo TerasawaOriginal AssigneeHitachi, Ltd.Export CitationBiBTeX, EndNote, RefManPatent Citations (10), Non-Patent Citations (2), Referenced by (55), Classifications (13), Legal Events (6) External Links: USPTO, USPTO Assignment, EspacenetMethod of and apparatus for detecting defect on photomaskUS 5235400 AAbstract A method of and an apparatus for detecting a defect on a phase-shifting mask for use in a projection aligner in which either or both of respective intensities of transmitted and reflected light beams from the mask illuminated with light are used for detecting a defect on the mask.
8. A method according to claim 5, wherein the phase-shifting mask includes phase-shifting means for shifting a phase of light in the first and second light beams by a phase angle substantially equal to 180 first and second light beams pass through the phase-shifting mask.
Referring now to FIG. 2A, let us consider a case where a light shielding area 22 of the photomask 5 includes two apertures 20-1 and 20-2 of the same size, and only the aperture 20-2 is coated with a transparent, non-defective film 21. Then, an image shown in FIG. 2B is stored in the frame memory 12. Bright portions 23-1 and 23-2 shown in FIG. 2B correspond to the apertures 20-1 and 20-2, respectively, and the portions 23-1 and 23-2 are equal in shape to each other. In a case where a part 24 of the transparent film 21 is removed as shown in FIG. 3A, an image shown in FIG. 3B is sent to the comparing/discriminating circuit 17 through the frame memory 12. As shown in FIG. 3B, a dark line 25 is formed along the contour of the film lacking part or defect 24. This is because the wavelength of the coherent or partially coherent illumination light is selected such that the transparent film 21 shifts the phase of the illumination light by a phase angle of 180 the film lacking part 24 on the basis of interference between light passing through, the film lacking part 24 and light passing through the transparent film 21 outside of the film lacking part 24. The defect 24 in the transparent film 21 can be detected by recognizing the dark line 25. The image of the photomask 5 can be formed on the imaging device 9 at one time. Alternatively, the illumination light is focused on the photomask 5 to form an image of a very fine area of the photomask 5 on the imaging device 9, and the photomask 5 is scanned with the focused illumination light to obtain the image of the whole of the photomask 5.
Embodiment II FIG. 4 shows a second embodiment of an apparatus for detecting a defect on a photomask in accordance with the present invention. According to the present embodiment, in addition to the detection of the contour of a defect in a thin transparent film serving as a phase shifter, it is determined whether a defect bringing about a phase shift of 0 present in a light transmitting area which produces a phase shift of 180 from the light source 1 passes through a collimator lens 3' and the wavelength selection filter 2. The parallel rays thus obtained are separated by a beam splitter 30-1 into two light beams, one of which is directed to an imaging device 34 through a focusing lens 33-2 without passing through the photomask 5 to be used as a reference light beam. The other light beam is focused on the photomask 5 by a focusing lens 31. The transmitted light from the photomask 5 passes through a collimator lens 32. The parallel rays thus obtained are separated by a beam splitter 30-2 into two light beams, one of which is incident on the imaging device 9 through a focusing lens 33-1. The other light beam from the beam splitter 30-2 and the reference light beam from the beam splitter 30-1 are caused to interfere. The resultant light beam thus obtained is incident on the imaging device 34. The position of the stage 4 mounted with the photomask 5 is always measured by the laser interferometer (not shown). That is, a light focusing position on the photomask 5 is always measured.
According to the optical system shown in FIG. 4, when the illumination light passing through the photomask 5 is not subjected to any phase shift, bright light is incident on each of the imaging devices 9 and 34. Let us consider a case where the photomask 5 is provided with a thin film for shifting the phase of the illumination light by a phase angle of about 180 light, it is determined that the thin film does not exist at the light focusing position on the photomask 5. When the imaging device 9 receives bright light and the imaging device 34 receives dark light, it is determined that the thin film exists at the light focusing position on the photomask 5. When, the imaging device 9 receives dark light, it is determined that the light focusing position on the photomask lies in a light shielding area. The output signals of the imaging devices 9 and 34 are applied to an arithmetic circuit 37 which produces three levels. These levels are applied to the comparing/discriminating circuit 17 to be compared with design data. Thus, a defect in the thin film serving as a phase shifter can be detected. The arithmetic circuit 37 includes comparators 41 and 42 for converting the output signals of the imaging devices 9 and 34 into digital signals, and a level generator 43 for generating three levels in accordance with the digital signals from the comparators 41 and 42.
In a case where the phase of the light passing through the photomask fluctuates widely because of the nonuniform thickness of a mask substrate, the present embodiment may fail to detect a defect in the thin film serving as a phase shifter. However, when the photomask 5 is scanned by the focused illumination light, the time variation of transmitted light quantity due to the nonuniform thickness of the mask substrate will be far smaller than the time variation of transmitted light quantity due to the presence or absence of the thin film. Accordingly, it is possible to discriminate between a change in transmitted light quantity due to the nonuniform thickness of the mask substrate and a change in transmitted light quantity due to the thin film. In more detail, when a position on the photomask 5 where the intensity of light due to interference between the transmitted light and the reference light varies by more than a predetermined amount is detected in a scanning period, such a position represents the boundary between a light transmitting portion bringing about no phase shift and a light transmitting portion bringing about a phase shift of about 180 37 has a function of detecting the intensity variation of light incident on the imaging device 34 and a signal corresponding to the detected intensity variation is applied to the comparing/discriminating circuit 17 to be compared with design data, the film lacking part 24 of FIG. 3A can be detected.
The present embodiment utilizes a fact that the transmittance of a phase shifter is decreased for light lying in a wavelength range Alternatively, the phase shifter may be formed of a polarizer. In this case, linearly-polarized light inclined at 45 polarization of the polarizer is used as illumination light. Then, the chromium film intercepts the illumination light, the quantity of light passing through the polarizer is one half the quantity of the illumination light incident thereon, and the illumination light passing through the exposed surface area of the transparent substrate is scarcely absorbed by transparent substrate.
Embodiment V FIG. 8 shows a fifth embodiment of an apparatus for detecting a defect on a photomask in accordance with the present invention. As shown in FIG. 8, the present embodiment includes the light source 1, a band pass filter 82, an illuminating optical system 83, the stage 4 for holding the photomask 5 thereon, a receiving optical system 85, a beam splitter 86, band pass filters 87a and 87b, photo-sensors 88a and 88b, the arithmetic circuit 37, the comparing/discriminating circuit 17, and the drive means 6 for moving the stage 4. A mercury-xenon lamp is used as the light source 1, and the filter 82 transmits only a wavelength component of 254 nm and a wavelength component of 436 nm. These wavelength components pass through the illuminating optical system 83, and are then incident on the photomask 5 which is fixed to the stage 4. As in the fourth embodiment, the photomask 5 has the structure shown in FIG. 7. The thickness of the phase shifter 73 shown in FIG. 7 is selected so that the phase shifter 73 shifts the phase of the wavelength component of 436 nm by a phase angle of π or 180
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS3972616 *Jun 27, 1975Aug 3, 1976Tokyo Shibaura Electric Co., Ltd.Apparatus for detecting the defects of the mask pattern using spatial filteringUS4559603 *Sep 23, 1983Dec 17, 1985Tokyo Shibaura Denki Kabushiki KaishaApparatus for inspecting a circuit pattern drawn on a photomask used in manufacturing large scale integrated circuitsUS4623256 *Nov 26, 1984Nov 18, 1986Kabushiki Kaisha ToshibaApparatus for inspecting mask used for manufacturing integrated circuitsUS4679938 *Jun 3, 1985Jul 14, 1987International Business Machines CorporationDefect detection in films on ceramic substratesUS4681442 *Mar 18, 1985Jul 21, 1987International Business Machines CorporationMethod for surface testingUS4952058 *Apr 22, 1988Aug 28, 1990Hitach, Ltd.Method and apparatus for detecting abnormal patternsJPH06267514A * Title not availableJPS5762052A * Title not availableJPS58173744A * Title not availableJPS62189468A * Title not available* Cited by examinerNon-Patent CitationsReference1 *SPIE, vol. 633 Optical Microlithography V(1986), pp. 138 144, Yabumoto et al.2SPIE, vol. 633 Optical Microlithography V(1986), pp. 138-144, Yabumoto et al.* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS5353116 *Nov 13, 1992Oct 4, 1994Sharp Kabushiki KaishaDefect inspection system for phase shift masksUS5379348 *Mar 31, 1993Jan 3, 1995Kabushiki Kaisha ToshibaPattern defects inspection systemUS5410400 *Jun 23, 1992Apr 25, 1995Hitachi, Ltd.Foreign particle inspection apparatusUS5432684 *Jan 11, 1994Jul 11, 1995Delco Electronics Corp.Process for manufacturing painted backlit displays having uniform backlighting intensityUS5440566 *Apr 6, 1994Aug 8, 1995Southwest Research InstituteFault detection and diagnosis for printed circuit boardsUS5481624 *Apr 13, 1993Jan 2, 1996Mitsubishi Denki Kabushiki KaishaMask inspecting method and mask detectorUS5723843 *Jan 28, 1993Mar 3, 1998Illuminated Display Division Of Bell Industries, Inc.Method of forming and balancing an illuminated display panelUS5760902 *Aug 14, 1995Jun 2, 1998The United States Of America As Represented By The Secretary Of The ArmyMethod and apparatus for producing an intensity contrast image from phase detail in transparent phase objectsUS5816970 *Dec 26, 1996Oct 6, 1998Samsung Electronics Co., Ltd.Semiconductor fabricating apparatus with remote belt tension sensorUS5830607 *May 27, 1997Nov 3, 1998Mitsubishi Denki Kabushiki KaishaPhase shift mask and manufacturing method thereof and exposure method using phase shift maskUS5892579 *Apr 16, 1997Apr 6, 1999Orbot Instruments Ltd.Optical inspection method and apparatusUS5917588 *Nov 4, 1996Jun 29, 1999Kla-Tencor CorporationAutomated specimen inspection system for and method of distinguishing features or anomalies under either bright field or dark field illuminationUS5981967 *Dec 17, 1997Nov 9, 1999Texas Instruments IncorporatedMethod and apparatus for isolating defects in an integrated circuit near field scanning photon emission microscopyUS6091075 *Jun 1, 1998Jul 18, 2000Hitachi, Ltd.Automatic focus detection method, automatic focus detection apparatus, and inspection apparatusUS6094305 *Oct 27, 1997Jul 25, 2000Nikon CorporationExposure method and apparatus thereforUS6172749 *Feb 3, 1998Jan 9, 2001Advantest CorporationMethod of and apparatus for detecting a surface condition of a waferUS6184976 *Oct 9, 1997Feb 6, 2001Samsung Electronics Co., Ltd.Apparatus and method for measuring an aerial image using transmitted light and reflected lightUS6285783 *Sep 25, 1997Sep 4, 2001Kabushiki Kaisha ToshibaPattern data generating apparatus and method for inspecting defects in fine patterns in a photomask or semiconductor waferUS6476913 *Nov 29, 1999Nov 5, 2002Hitachi, Ltd.Inspection method, apparatus and system for circuit patternUS6480279 *Apr 11, 2001Nov 12, 2002Hitachi, Ltd.Inspection method, apparatus and system for circuit patternUS6512578 *Jul 9, 1998Jan 28, 2003Nikon CorporationMethod and apparatus for surface inspectionUS6759297Feb 28, 2003Jul 6, 2004Union Semiconductor Technology CorporatinLow temperature deposition of dielectric materials in magnetoresistive random access memory devicesUS6759655Apr 11, 2001Jul 6, 2004Hitachi, Ltd.Inspection method, apparatus and system for circuit patternUS6765673Jul 13, 2000Jul 20, 2004Kabushiki Kaisha ToshibaPattern forming method and light exposure apparatusUS6803554Nov 7, 2003Oct 12, 2004Brion Technologies, Inc.System and method for lithography process monitoring and controlUS6806456Aug 22, 2003Oct 19, 2004Brion Technologies, Inc.System and method for lithography process monitoring and controlUS6807503Oct 2, 2003Oct 19, 2004Brion Technologies, Inc.Method and apparatus for monitoring integrated circuit fabricationUS6820028Jan 23, 2004Nov 16, 2004Brion Technologies, Inc.Method and apparatus for monitoring integrated circuit fabricationUS6828542Mar 18, 2003Dec 7, 2004Brion Technologies, Inc.System and method for lithography process monitoring and controlUS6842245 *Jan 16, 2003Jan 11, 2005Nec Electronics CorporationPattern test deviceUS6879924Jan 22, 2004Apr 12, 2005Brion Technologies, Inc.Method and apparatus for monitoring integrated circuit fabricationUS6884984Jan 12, 2004Apr 26, 2005Brion Technologies, Inc.System and method for lithography process monitoring and controlUS6892156Jun 22, 2004May 10, 2005Brion Technologies, Inc.Method and apparatus for monitoring integrated circuit fabricationUS6906305Jan 7, 2003Jun 14, 2005Brion Technologies, Inc.System and method for aerial image sensingUS6959255Jan 13, 2004Oct 25, 2005Brion Technologies, Inc.Method and apparatus for monitoring integrated circuit fabricationUS6969837Jun 9, 2004Nov 29, 2005Brion Technologies, Inc.System and method for lithography process monitoring and controlUS6969864Jun 21, 2004Nov 29, 2005Brion Technologies, Inc.System and method for lithography process monitoring and controlUS7019835 *Feb 19, 2004Mar 28, 2006Molecular Imprints, Inc.Method and system to measure characteristics of a film disposed on a substrateUS7053355Aug 25, 2005May 30, 2006Brion Technologies, Inc.System and method for lithography process monitoring and controlUS7233874Jan 24, 2005Jun 19, 2007Brion Technologies, Inc.Method and apparatus for monitoring integrated circuit fabricationUS7292326Nov 30, 2004Nov 6, 2007Molecular Imprints, Inc.Interferometric analysis for the manufacture of nano-scale devicesUS7491959 *Sep 26, 2006Feb 17, 2009Kabushiki Kaisha ToshibaDefect inspection apparatusUS7630067Nov 30, 2004Dec 8, 2009Molecular Imprints, Inc.Interferometric analysis method for the manufacture of nano-scale devicesUS7738089 *Sep 3, 2004Jun 15, 2010Kla-Tencor Technologies Corp.Methods and systems for inspection of a specimen using different inspection parametersUS7785096Feb 20, 2009Aug 31, 2010Molecular Imprints, Inc.Enhanced multi channel alignmentUS7785526Jul 20, 2004Aug 31, 2010Molecular Imprints, Inc.Imprint alignment method, system, and templateUS7880872Oct 8, 2009Feb 1, 2011Molecular Imprints, Inc.Interferometric analysis method for the manufacture of nano-scale devicesUS8366434 *Jul 13, 2010Feb 5, 2013Molecular Imprints, Inc.Imprint alignment method, system and templateUS8384887Jun 8, 2010Feb 26, 2013Kla-Tencor Technologies Corp.Methods and systems for inspection of a specimen using different inspection parametersUS20100278955 *Jul 13, 2010Nov 4, 2010Molecular Imprints, Inc.Imprint Alignment Method, System and TemplateUSH1972Oct 6, 1998Jul 3, 2001Nikon CorporationAutofocus system using common path interferometryDE102007049099A1 *Oct 11, 2007Apr 23, 2009Vistec Semiconductor Systems GmbhCoordinate measuring machine for determining phase relationship of mask i.e. phase shift mask, during manufacture of semiconductor, has optical unit, where phase differences are determined based on optical unit together with detectorEP0628806A2 *Apr 28, 1994Dec 14, 1994International Business Machines CorporationImage measurement system and methodEP0819933A2 *Jul 1, 1997Jan 21, 1998Orbot Instruments LimitedOptical inspection method and apparatusEP1210586A1 *Sep 1, 2000Jun 5, 2002Resolve Engineering Pty LtdDetection of inclusions in glass* Cited by examinerClassifications U.S. Classification356/237.5, 356/520, 250/559.44, 356/394, 250/559.8International ClassificationG01N21/45, G01N21/956, G03F7/20Cooperative ClassificationG01N21/45, G03F7/70866, G01N21/956European ClassificationG03F7/70P6B, G01N21/956Legal EventsDateCodeEventDescriptionOct 4, 2005FPExpired due to failure to pay maintenance feeEffective date: 20050810Aug 10, 2005LAPSLapse for failure to pay maintenance feesFeb 23, 2005REMIMaintenance fee reminder mailedJan 30, 2001FPAYFee paymentYear of fee payment: 8Feb 5, 1997FPAYFee paymentYear of fee payment: 4Oct 10, 1989ASAssignmentOwner name: HITACHI, LTD.,, JAPANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:TERASAWA, TSUNEO;HASEGAWA, NORIO;TANAKA, TOSHIHIKO;AND OTHERS;REEL/FRAME:005155/0541Effective date: 19891002RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google