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
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
• • 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
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/0005—Production of optical devices or components in so far as characterised by the lithographic processes or materials used therefor
  • G03F7/0007—Filters, e.g. additive colour filters; Components for display devices
• • 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
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/70—Microphotolithographic exposure; Apparatus therefor
  • G03F7/70216—Mask projection systems
  • G03F7/70283—Mask effects on the imaging process
  • G03F7/70291—Addressable masks, e.g. spatial light modulators [SLMs], digital micro-mirror devices [DMDs] or liquid crystal display [LCD] patterning devices

Definitions

• the invention generally relates to the field of lithography for making multi-layer structures of at least two layers deposited on a substrate and more particularly to mask alignment of different structural elements building-up the multi-layer structures.
• Color filters and color converters for color display applications are currently fabricated using standard photolithographic processes which consist of the following necessary steps:
• step f) the removal of developed photoresist (so-called positive photolithographic process) alternatively the non- developed photoresist material can be removed (so-called negative photolithographic process) .
• U.S. Patent No. 5,688,551 discloses a method of forming a multicolor organic electro-luminiscent (EL) display panel using a close-spaced deposition technique to form a separately colored organic EL medium on a substrate by transferring, patternwise, the organic EL medium from a donor sheet to the substrate. More specifically, a transparent conductive layer is formed and patterned to provide a plurality of spaced electrodes on a transparent substrate. Further, on the spaced electrodes, color organic EL media are provided by close-spaced deposition from the donor sheet forming adjacent colored subpixels which emit the primary colors, respectively. In addition, a conductive layer is formed and patterned on the colored subpixels to provide a plurality of spaced electrodes.
• the close-spaced deposition is provided by transferring to the transparent substrate each of the colored organic EL media by illuminating the respective donor sheet which is pre-patterned with a light absorbing layer. That method allegedly does not require conventional photolithography and thus shall avoid the incompatibility issues of the organic EL medium with photolithography processes .
• U.S. Patent No. 4,743,099 discloses a method of making a thin film transistor (TFT) liquid crystal (LC) color display device which provides alignment between red-green-blue color filters and pixel electrodes by using the electrodes to create the color filters in a polychromatic glass.
• the method uses an assembly having spaced front and rear glass panels, one of which is an unexposed polychromatic glass material.
• a transparent common electrode layer is formed on the inside surface of one of the glass panels.
• An array of individually addressable pixel electrodes is formed on the inside surface of the other of the glass panels.
• the cavity defined by the glass panels is temporarily filled with a liquid crystal material doped with an opaque substance. Ultraviolet light is directed at the non-polychromatic glass panel.
• the pixel electrodes associated with one color are then addressed to selectively switch the liquid crystal to a transparent state and thus locally exposing certain regions of the polychromatic glass panel by the external ultraviolet light. Thereby certain hue in those areas are created and the procedure is repeated with different electrodes to establish different hues in different regions of the polychromatic glass panel.
• the assembly is then heat treated to fix the established hues.
• the assembly finally is completed by removing the temporary liquid crystal material from the cavity and replacing it with a suitable, permanent liquid crystal material.
• the known techniques have common the drawback that they require the number of deposited layers actively to be aligned to each other thus requiring at least a corresponding number of deposition and alignment steps.
• the idea underlying the invention is to use a radiation of the structure elements themselves, i.e. light or radiation self- irradiated by the structure elements, for the lithographic exposure of e.g. a covering layer and thus to achieve spatial self-alignment between the different layers.
• the invention makes use of the fact that structured monochromatic devices, e.g. symbols or pixels, can already be used as irradiation or light sources in the photolithographic process for the fabrication of structured full-color devices like color filters, color converters, black masks, studs etc.
• structured monochromatic devices e.g. symbols or pixels
• Exemplary structure elements can be light emitting diodes or vertical cavity lasers.
• the step of exposing the at least second layer with a physical and/or chemical interaction further uses the fact that, on the one hand, any interaction that is originated by the structure elements can be used to structure the at least second layer by a lithographic process based on said interaction.
• any interaction or physical and/or chemical property of the second layer that can at least be modulated by the structure elements is sufficient for the proposed mechanism.
• Said physical and/or chemical interaction can also be any electric or magnetic or thermal interaction between the first layer and the at least second layer appropriate for said image transfer, e.g. a magnetic field or an electric current.
• the proposed mechanism avoids the aforementioned time- and cost-extensive alignment steps. Additionally it guarantees that the different layers of a structure fabricated using that mechanism are self-aligned to each other without need of a particular alignment step or technique. Due to the inherent near-field character of the proposed technique, a very high spatial resolution of the fabricated devices or structures and a precise alignment between the respective different layers can easily be obtained.
• the proposed mechanism is technically non-complex vis-a-vis the known approaches insofar as some of the prementioned necessary alignment steps become obsolete thus reducing the time and cost efforts for its implementation.
• the mechanism can be implemented using known technology or even existing structures. It only requires that the material used for the first layer is emitting a radiation adequate to enable radiation-induced development and structuring of the mask layer (s) i.e. the radiation used must be able to influence or change a mechanical, physical or chemical property of the mask material so that mask material can be removed in a well- defined manner during a lithographic step.
• the mechanism advantageously allows that the substrate to be structured must not be planar, but can also be flexible or even bent during the structuring process.
• LEDs light emitting diodes
• OLEDs organic electro-luminescent image display devices
• pLEDs polymer LEDs
• photolithographic methods e.g. positive or negative photolithographic processes or lift-off techniques
• photolithographic methods e.g. positive or negative photolithographic processes or lift-off techniques
• the invention can either be implemented by using the pre-mentioned self-emitting devices or by using passively emitting structures comprised of a radiation-absorptive material, e.g. a thermal absorptive, fluorescent or phosphorescent material.
• a radiation-absorptive material e.g. a thermal absorptive, fluorescent or phosphorescent material.
• the structures can be initiated to reemit a radiation adequate for the photoresist development process step by irradiating the structures with another radiation of a basically different wavelength. Only exemplarily, this could be achieved by irradiating the structures with a non-thermal radiation like ultraviolet rays and using a thermally sensitive resist as lithographic material.
• Fig. la, b show procedural steps of a first embodiment of the method according to the invention, wherein a. is an example for manufacturing a black matrix color display and b. an example for manufacturing a color display without a black matrix;
• Fig. 2 shows procedural steps of a.second embodiment of the invention
• Fig. 3 depicts an enlarged sectional side view of a masking substrate according to the invention.
• Fig. 4 shows procedural steps of a third embodiment of the invention.
• Fig. la shows a first embodiment of a lithographic process in accordance with the invention for manufacturing a full-color black-matrix display on a plain substrate 10. It is noteworthy that instead of using a plain or flat substrate, the process described in the following can also be performed on a non-flat or even bent substrate.
• the black mask 30 and color converters 30, 40 for green and red emission are added.
• the blue emitting devices 20 (step A) are coated with photoresist 50, which is then exposed by the light 25 of the blue emitter (step B) .
• the black matrix 30 principally can be produced by a positive or negative lithographic process (C) .
• photoresists doped with suitable dyes can be used. Therefore, only an exposure (D) and development (E) cycle, but no mask fabrication and alignment, as in the prior art, is needed to produce a structured full-color device where the pixel combination produced in steps D & E is used for generating green color light (not shown) and the combination of steps F & G for generating red color (not shown) .
• the second example illustrated in Fig. lb is for a full-color display not comprising a black matrix. Therefore this example does not require steps B and C in Fig. la. For the other steps D' to G' it is referred to the corresponding steps D to G in Fig. la.
• procedural steps A'' and B' ' are identical with the pre-described embodiments.
• structure elements 20 deposited on a substrate 10 are over- coated by a photoresist layer 50.
• the structure elements 20 consist of a material which is re-emitting a radiation after being irradiated with a radiation like a thermal radiation.
• the photoresist material 50 has to be development-sensitive with respect of that radiation, i.e. in the case of thermal radiation able to be developed by means of the re-emitted radiation.
• step 60 where the over- coated substrate is irradiated with a radiation 60 thus initiating the structure elements 20 to re-emit radiation 25.
• steps E' ' - G' ' are similar or identical with the corresponding steps in the other embodiments.
• Fig. 3 depicts an enlarged sectional side view of a masking substrate according to the invention which can be fabricated as a pre-configured masking device.
• the device consists of a substrate 10 and pre-deposited and pre-structured elements 20, in this example comprising a black matrix 30 between the elements 20.
• the masking device can be pre-coated with a photoresist 50 appropriate for being developed by the radiation 25 emitted by the elements 20.
• Emission of the elements 20 can be controlled by voltage supply lines 80 so that the mechanism proposed by the invention and described above allows fabrication of even complex structure patterns like those being used in semiconductor manufacturing.
• Fig. 4 shows a rigid or flexible substrate 100 bearing a first layer of conducting paths 105 (step A) .
• the first layer 105 is coated with an isolating resist 110 sensitive to thermal interaction (step B) .
• an electric current is switched on (step C) . Due to the internal resistance these paths heat up 120 and thus locally expose the resist 110, i.e. change a physical and/or chemical property of the resist 110 like its hardness or chemical resistance against a solvent.
• the resist is removed, leaving the conducting paths 115 that were switched on with an isolating coating 125 of the resist (step D) .
• subsequent layers 130 of conducting paths can be deposited on top of the first layer, e. g. creating interconnects between different conducting paths 135, 140 (step E) .
• the advantage of the pre-described method is that complicated and expensive processes involving mask technology to protect certain conductive paths and to deposit insulating protection layers on other paths is not necessary. Simple coating techniques for the thermally sensitive resist and the self- generation of the thermal energy necessary for exposing the resist due to the internal resistance of the conductive paths are used instead.
• the method and device according to the invention can be used in micro-fabrication of any micro-technique using mask lithography.
• thin film optical devices like liquid crystal displays (LCDs) , thin film transistor (TFT) displays, organic light emitting diode (OLED) displays, or color filters or color converters.
• LCDs liquid crystal displays
• TFT thin film transistor
• OLED organic light emitting diode
• color filters or color converters Thereupon it can be used for the fabrication of semiconductor devices (processors, storages, etc.) or opto-electronic devices.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Electroluminescent Light Sources (AREA)
• Photosensitive Polymer And Photoresist Processing (AREA)

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• 2002
  • 2002-02-05 WO PCT/EP2002/001140 patent/WO2002067054A2/en not_active Ceased
  • 2002-02-05 JP JP2002566721A patent/JP2004530255A/ja active Pending
  • 2002-02-05 KR KR1020037010417A patent/KR100582830B1/ko not_active Expired - Fee Related
  • 2002-02-05 AU AU2002229742A patent/AU2002229742A1/en not_active Abandoned
  • 2002-02-05 EP EP02710837A patent/EP1433027A2/de not_active Withdrawn

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