WO1999063406A1 - Photomasques a base d'argent - Google Patents

Photomasques a base d'argent Download PDF

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Publication number
WO1999063406A1
WO1999063406A1 PCT/GB1999/001484 GB9901484W WO9963406A1 WO 1999063406 A1 WO1999063406 A1 WO 1999063406A1 GB 9901484 W GB9901484 W GB 9901484W WO 9963406 A1 WO9963406 A1 WO 9963406A1
Authority
WO
WIPO (PCT)
Prior art keywords
emulsion
photomask
substrate
silver
silver halide
Prior art date
Application number
PCT/GB1999/001484
Other languages
English (en)
Inventor
James Anthony Cairns
Original Assignee
University Of Dundee
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by University Of Dundee filed Critical University Of Dundee
Priority to JP2000552555A priority Critical patent/JP2002517785A/ja
Priority to EP99923736A priority patent/EP1092173A1/fr
Priority to AU40501/99A priority patent/AU4050199A/en
Publication of WO1999063406A1 publication Critical patent/WO1999063406A1/fr

Links

Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F1/00—Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
    • G03F1/54—Absorbers, e.g. of opaque materials

Definitions

  • This invention relates to photomasks, ie. masks that are used mainly in the processing of semiconductor materials during production of integrated circuits (i.c.s) and similar devices.
  • a photomask comprises a substrate (typically of quartz) usually having a flat upper surface to which is bonded a layer of Chromium in a pattern of lines and interconnections desired in an i.e. manufactured using the photomask.
  • Radiation (typically in the ultra-violet wavelength) is projected via the photomask onto a semiconductor material. The radiation is blocked where the Chromium is present and passes through the mask at locations that lack Chromium. Under appropriate chemical and physical conditions the radiation that passes through the mask to the semiconductor is used to define the circuit pattern.
  • the masks are manufactured by producing the quartz substrate 11 having a flat upper surface 12 and completely coating the surface 12 with a layer 13 of Chromium. Next a layer 14 of resist is bonded onto the top surface of the Chromium layer 13 to coat it completely.
  • a resist is a material whose properties are altered by electron bombardment or laser irradiation.
  • the electron beam resist most commonly used in photomasks is polybutyl sulphone.
  • the desired circuit pattern is then formed in the resist layer, by, for example, projection of a beam 15 of electrons from an electron beam generator the output of which is usually computer controlled. This is shown at step (i) in Figure 1.
  • the resist is then developed by means of an appropriate liquid, thereby producing openings in the resist, as shown at 14a (step (ii)).
  • a liquid etchant typically eerie ammonium nitrate solution
  • the etchant attacks the Chromium in the regions of the mask where the resist layer has been removed.
  • the result is the partially completed mask 10b, shown at step (iii) in Figure 1 , having modified photoresist layer 14a and a similarly modified (ie. etched) Chromium layer 13a.
  • the photoresist layer is removed typically by means of an oxygen gas plasma treatment. This results in the completed photomask 10c having the modified Chromium layer 13a that is the pattern desired in the i.c.s manufactured using the photomask.
  • This manufacturing process is time consuming primarily because it is a multi-stage process.
  • the use of a liquid to remove the unwanted Chromium is disadvantageous.
  • the etching solution dissolves the Chromium isotropically (ie. in all directions simultaneously) so that the lines etc. cut by the liquid etchant broaden as the dissolution takes place. This limits the resolution to which the lines may be defined. In other words, the narrowness of the lines etc, is limited by the liquid etchant.
  • the production of the i.c.s involves an optical reduction system that reduces the size of the pattern on the photomask by typically a factor of five.
  • the narrowest lines attainable are approximately l ⁇ m wide. This limits the resolution of the circuitry that may be formed on a semiconductor.
  • the known method for producing photomasks can lead to the production of faulty i.c.s. For example a small region of the photoresist or the Chromium may be inadvertently not removed in the photomask manufacturing process. Such flaws must be corrected before the photomask is supplied to the i.e. manufacturer.
  • a method of manufacturing a photomask comprising the steps of: providing a substrate supporting an emulsion including a photosensitive silver halide; and directing photons and/or electrons at the emulsion to interact with the silver halide to define a desired pattern on the substrate, after development, of silver.
  • the substrate preferably is quartz or glass.
  • the emulsion can readily include silver bromide particles of a size that permits production of extremely high resolution silver particles in the mask, thereby improving the resolutions achievable in the i.c.s.;
  • Chromium in the prior art remaining in parts of the mask from which they should be absent.
  • the emulsion is of or includes a photosensitive silver halide, especially silver bromide; and a gel, preferably gelatin.
  • the emulsion may be similar to, or may indeed be, a photographic emulsion.
  • the method of the invention preferably includes the step of applying the emulsion onto the substrate by conventional methods used to manufacture photographic emulsion plates.
  • the emulsion is capable of defining a pattern of a resolution in the range 0.1 to 1 micron. In practice this is achieved through judicious choice of the silver bromide particle size.
  • the invention also resides in a photomask manufactured by a method as defined herein.
  • a blank or a photomask comprising a substrate supporting an emulsion including a photosensitive silver halide.
  • the emulsion may be of or may include a photosensitive silver halide, especially silver bromide, and a gel, particularly gelatin.
  • the emulsion is stabilised.
  • the emulsion is capable of defining a pattern of a resolution in the range 0.1 to 1 micron.
  • the substrate preferably is quartz or glass.
  • the invention also extends to use of a blank or a photomask as defined herein in the manufacture of an electronic device, especially a semiconductor device.
  • an emulsion for use in a method and/or a blank and/or a photomask as defined herein, the emulsion including a photosensitive silver halide, especially silver bromide, and being capable of defining a pattern, on a substrate, having a resolution in the range 0.1 to 1 micron.
  • the emulsion is of or includes a photosensitive silver halide, especially silver bromide, and a gel, especially gelatin.
  • Figure 1 shows schematically a prior art method of manufacturing a photomask
  • Figure 2 shows schematically a blank for forming a photomask; a method; and a photomask according to the invention.
  • FIG. 2 there is shown a blank 9 according to the invention and having a quartz or glass substrate 11 having a substantially flat upper surface 12 to which is secured an emulsion of preferably silver bromide particles 17 and gelatin 18 in a layer 16.
  • Another photosensitive silver halide may alternatively be used, although silver bromide is presently preferred because of ease of availability.
  • Gelatin is the preferred gel since it suspends the silver halide particles homogenously at spacings consistent with the desired line resolutions in the photomask. Also, of course, gelatin is transparent.
  • the emulsion is initially coated, eg. by spinning, onto the upper surface of the quartz substrate.
  • an electron beam writer or a laser writer such as used conventionally to manufacture photomasks as described hereinabove is used under computer control to apply a beam of electrons or photons to the stabilised emulsion.
  • the controller for the electron beam generator causes the electron beam to describe a desired pattern of movement.
  • the beam in turn causes the reaction:
  • the electron beam dose required in the first step of the mask production process is much smaller than that required for a conventional electron beam resist, such as polybutyl sulphone.
  • the required electron beam dose is typically at least 50 times less any in some cases need only be 100 times less than that required for polybutyl sulphone.
  • the manufacture of the photomask is advantageously quick.
  • Use of the laser or electron beam as indicated in step (i) of Figure 2, followed by immersion in a developer results in the partly completed photomask lOd shown at step (ii).
  • the layer 16 has been modified to include regions 20 of solid silver and regions of the unreacted AgBr/gelatin emulsion 17,18.
  • the layer 16 is "fixed", eg. through use of sodium thiosulphate (IV) solution, which removes the excess, unreacted Ag Br as a soluble complex ion (Ag (S 2 O 3 ) 2 ) 3" so that the silver alone remains in situ in layer 16.
  • IV sodium thiosulphate
  • the photomask of the invention may be used in the same way as prior art photomasks, ie. it may be inserted into a string of components including a focussing device and a reducing apparatus known per se whereby to project ultra-violet radiation onto a semiconductor substrate for the purposes of etching the semiconductor and/or producing conductors such as noble metal tracks.
  • the preferred emulsion may be manufactured by precipitating AgBr particles and mixing them with gelatin to create an emulsion of the desired properties. If necessary the rate of precipitation of the particles may be controlled to a rate suitable to produce fine particles that permit the fine resolutions mentioned herein to be achieved. Typically the diameters of the nucleated AgBr particles are in the range 1.0 - 0. l ⁇ m.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Preparing Plates And Mask In Photomechanical Process (AREA)

Abstract

Dans le domaine de la fabrication des photomasques pour semiconducteurs, il est nécessaire d'accélérer le processus de production des photomasques et de fabriquer des photomasques présentant moins de défauts. Il est également nécessaire de produire des photomasques permettant d'obtenir des circuits d'une résolution beaucoup plus fine que les circuits connus jusqu'à présent. La présente invention concerne un procédé de fabrication de photomasque (10) selon lequel on recouvre un substrat (11) d'une émulsion de gélatine (18) et d'un halogénure d'argent photosensible (17). Lorsqu'il est exposé à un faisceau d'électrons (15) ou à un faisceau laser commandé de façon à générer un motif désiré, l'halogénure d'argent réduit et crée un photomasque (10), après développement et fixation.
PCT/GB1999/001484 1998-05-30 1999-05-28 Photomasques a base d'argent WO1999063406A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
JP2000552555A JP2002517785A (ja) 1998-05-30 1999-05-28 銀系フォトマスク
EP99923736A EP1092173A1 (fr) 1998-05-30 1999-05-28 Photomasques a base d'argent
AU40501/99A AU4050199A (en) 1998-05-30 1999-05-28 Silver based photomasks

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9811563.7 1998-05-30
GB9811563A GB9811563D0 (en) 1998-05-30 1998-05-30 Improvements in and relating to photomasks

Publications (1)

Publication Number Publication Date
WO1999063406A1 true WO1999063406A1 (fr) 1999-12-09

Family

ID=10832905

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1999/001484 WO1999063406A1 (fr) 1998-05-30 1999-05-28 Photomasques a base d'argent

Country Status (5)

Country Link
EP (1) EP1092173A1 (fr)
JP (1) JP2002517785A (fr)
AU (1) AU4050199A (fr)
GB (1) GB9811563D0 (fr)
WO (1) WO1999063406A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010086850A2 (fr) 2009-01-29 2010-08-05 Digiflex Ltd. Procédé de production d'un photomasque sur une surface photopolymère
EP3893055A1 (fr) * 2021-01-18 2021-10-13 Longserving Technology Co., Ltd Procédé de fabrication d'un modèle de circuit à échelle picoscopique/nanoscopique

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1447607A1 (de) * 1963-02-27 1969-01-02 Noc Chemical Arts Inc Di Photographischer Film
US3567447A (en) * 1967-07-03 1971-03-02 Ibm Process for making masks photographically
US3716363A (en) * 1971-02-05 1973-02-13 Gte Laboratories Inc Method of making photomasks of the type used in the fabrication of microelectronic circuits
US4242438A (en) * 1974-09-06 1980-12-30 Fuji Photo Film Co., Ltd. Photomask material
JPS57139923A (en) * 1981-02-21 1982-08-30 Toshiba Corp Forming method for pattern by electron beam

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1447607A1 (de) * 1963-02-27 1969-01-02 Noc Chemical Arts Inc Di Photographischer Film
US3567447A (en) * 1967-07-03 1971-03-02 Ibm Process for making masks photographically
US3716363A (en) * 1971-02-05 1973-02-13 Gte Laboratories Inc Method of making photomasks of the type used in the fabrication of microelectronic circuits
US4242438A (en) * 1974-09-06 1980-12-30 Fuji Photo Film Co., Ltd. Photomask material
JPS57139923A (en) * 1981-02-21 1982-08-30 Toshiba Corp Forming method for pattern by electron beam

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
K.G. CLARK: "Processing of Emulsion Photomasks for Semiconductor Applications", SOLID STATE TECHNOLOGY, vol. 15, no. 6, June 1972 (1972-06-01), pages 29 - 36, XP002113747 *
P.H. JOHNSON ET AL.: "A Comparison of Silver Halide Systems as Applied to Toady's Advanced Semiconductor Requirements", SOLID STATE TECHNOLOGY, vol. 25, no. 1, January 1982 (1982-01-01), Port Washington, NY, USA, pages 75 - 85, XP002113748 *
PATENT ABSTRACTS OF JAPAN vol. 006, no. 238 (E - 144) 26 November 1982 (1982-11-26) *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010086850A2 (fr) 2009-01-29 2010-08-05 Digiflex Ltd. Procédé de production d'un photomasque sur une surface photopolymère
EP2562599A2 (fr) 2009-01-29 2013-02-27 Digiflex Ltd. Procédé de production d'un photomasque sur une surface photopolymérique
US9513551B2 (en) 2009-01-29 2016-12-06 Digiflex Ltd. Process for producing a photomask on a photopolymeric surface
EP3893055A1 (fr) * 2021-01-18 2021-10-13 Longserving Technology Co., Ltd Procédé de fabrication d'un modèle de circuit à échelle picoscopique/nanoscopique

Also Published As

Publication number Publication date
AU4050199A (en) 1999-12-20
GB9811563D0 (en) 1998-07-29
EP1092173A1 (fr) 2001-04-18
JP2002517785A (ja) 2002-06-18

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