Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
  • H01L31/02—Details
  • H01L31/0224—Electrodes
  • H01L31/022408—Electrodes for devices characterised by at least one potential jump barrier or surface barrier
  • H01L31/022425—Electrodes for devices characterised by at least one potential jump barrier or surface barrier for solar cells
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
  • H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
  • H01L31/06—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by potential barriers
  • H01L31/072—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by potential barriers the potential barriers being only of the PN heterojunction type
  • H01L31/0745—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by potential barriers the potential barriers being only of the PN heterojunction type comprising a AIVBIV heterojunction, e.g. Si/Ge, SiGe/Si or Si/SiC solar cells
  • H01L31/0747—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by potential barriers the potential barriers being only of the PN heterojunction type comprising a AIVBIV heterojunction, e.g. Si/Ge, SiGe/Si or Si/SiC solar cells comprising a heterojunction of crystalline and amorphous materials, e.g. heterojunction with intrinsic thin layer
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
  • H01L31/02—Details
  • H01L31/0216—Coatings
  • H01L31/02161—Coatings for devices characterised by at least one potential jump barrier or surface barrier
  • H01L31/02167—Coatings for devices characterised by at least one potential jump barrier or surface barrier for solar cells
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
  • H01L31/02—Details
  • H01L31/0224—Electrodes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
  • H01L31/02—Details
  • H01L31/0224—Electrodes
  • H01L31/022466—Electrodes made of transparent conductive layers, e.g. TCO, ITO layers
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
  • H01L31/02—Details
  • H01L31/0224—Electrodes
  • H01L31/022466—Electrodes made of transparent conductive layers, e.g. TCO, ITO layers
  • H01L31/022475—Electrodes made of transparent conductive layers, e.g. TCO, ITO layers composed of indium tin oxide [ITO]
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
  • H01L31/0248—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies
  • H01L31/036—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by their crystalline structure or particular orientation of the crystalline planes
  • H01L31/0392—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by their crystalline structure or particular orientation of the crystalline planes including thin films deposited on metallic or insulating substrates ; characterised by specific substrate materials or substrate features or by the presence of intermediate layers, e.g. barrier layers, on the substrate
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
  • H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
  • H01L31/1884—Manufacture of transparent electrodes, e.g. TCO, ITO
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E10/00—Energy generation through renewable energy sources
  • Y02E10/50—Photovoltaic [PV] energy

Definitions

• the present invention relates to a method for producing electrical contacts (for example, in the form of electrical tracks) on a component, in particular an electrical component such as. a solar cell or a light emitting diode, or even a precursor of a printed circuit board. Furthermore, the present invention relates to devices obtainable by this method.
• electrical contacts especially in the form of electrical conductors, are mounted on them.
• the electrical contacts serve, for example, to dissipate current from the component or to tap voltage from the component or to establish an electrical connection between electrical components that are present on the component. If the component is, for example, a solar cell, then the photocurrent generated by the photovoltaic effect in this semiconductor component can be dissipated via the electrical contacts.
• the component may be, for example, a precursor of a printed circuit board which is finally transferred into a printed circuit board (PCB) by the application of printed conductors.
• PCB printed circuit board
• a paste containing silver particles is applied to the component and then treated at a temperature high enough to cause coalescence of the silver particles. Therefore Temperatures of at least 800 ° C may be required. For many components, however, such high temperatures are unacceptable.
• a heterojunction solar cell e.g. A silicon heterojunction solar cell (SHJ solar cell) is an exemplary electrical device that is unsuitable for mounting electrical contacts at relatively high temperatures.
• the SHJ solar cell is a wafer-based crystalline silicon solar cell with an emitter and an amorphous silicon back- and front-surface field.
• Starting material is used for crystalline, in particular monocrystalline silicon, which is n- or p-doped (basic doping). On top of this, on both sides, first a very thin (about 1 to 10 nm) intrinsic (undoped) amorphous
• Silicon layer applied. This is followed on one side by the application of a very thin (about 10 to 50 nm), doped, amorphous silicon layer whose doping type (n- or p-type) is opposite to the base doping (amorphous emitter layer). On the other hand will be a thin (10 to 50 nm) amorphous
• the doping type of the basic doping corresponds (back or front surface field).
• a conductive transparent oxide (English: “Transparent Conductive Oxide” TCO) such as indium tin oxide (ITO) of 50-100 nm thickness is applied.To such a TCO layer usually has a sheet resistance at 25 ° C.
• TCO Transparent Conductive Oxide
• ITO indium tin oxide
• temperatures of more than 250 ° C should be avoided.
• the attachment of electrical contacts at the lowest possible temperature load is desirable.
• the sintering temperature of silver pastes can be lowered below 200 ° C.
• the costs of nanoparticles are significantly higher than for large particles or electrodeposited metals.
• pastes containing organic binders e.g.
• thermocrosslinking resins and silver particles in flake form The resin forms a matrix which holds the flakes together and produces adhesion to the outer layer of the electrical component (eg, a layer of transparent electrically conductive oxide (TCO) such as ITO).
• TCO transparent electrically conductive oxide
• ITO transparent electrically conductive oxide
• the tracks can be applied galvanically. This achieves a very good electrical conductivity of the conductor tracks.
• the surface must be printed with a mask of Galvano lacquer as a negative of the conductor pattern. After the electrodeposition, the paint must be removed in a chemical bath. The necessity of this resist mask makes this process but because of the material consumption and the necessary
• a thin metal layer or a metal layer stack is applied to the workpiece over the entire surface. Then, for example, a photoresist is applied and photo-lithographically in the form of a Negative mask of the tracks to be generated structured. Alternatively, the negative mask is already structured (recordable by means of inkjet) applied. The non-varnished surface is galvanically reinforced with copper and the copper is optionally protected from oxidation by an additional layer of silver.
• the vapor-deposited aluminum seed layer can be activated over the whole area by a zincate step. Subsequently, the application of a local barrier layer can take place. After the galvanic
• Deposition must have the barrier layer removed and the activated one
• PCB printed circuit boards
• An object of the present invention is to provide electrical contacts such as e.g. electrical traces on a component via a process that minimizes thermal stress on the component, avoids the use of masks (e.g., resist masks), and is as efficient as possible.
• electrical contacts such as e.g. electrical traces on a component via a process that minimizes thermal stress on the component, avoids the use of masks (e.g., resist masks), and is as efficient as possible.
• the object is achieved by a method for producing one or more electrical contacts on a component, comprising the following steps: Providing a component which has a front and a rear side, wherein an outer layer of a transparent, electrically conductive oxide (TCO) or a self-passivating metal or semiconductor is present on the front side and / or the rear side,
• TCO transparent, electrically conductive oxide
• Germ layer is not galvanic
• the method according to the invention comprises a component having a specific outer layer (TCO layer or layer of self-passivating metal or semiconductor) on which a galvanic deposition of conventional metals such as e.g. Copper is not possible or at least strongly inhibited.
• a galvanic deposition e.g., via a printing process
• seed layer still sufficiently low to effectively dissipate current from the component (for example, a solar cell) via the electrodeposited metal layer.
• the outer layer of a self-passivating metal or semiconductor is also referred to below as a self-passivation outer layer.
• Coatings made of a self-passivating metal or semiconductor form a thin oxide film at their surface even at room temperature.
• TCOs transparent, conductive oxides
• ITO Indium tin oxide
• Coatings of TCOs or self-passivating metals or semiconductors thus represent surfaces on which a galvanic metal deposition may be inhibited.
• these poorly electroplated surfaces quite a relatively low electrical
• Seed layer for the subsequent galvanization step A mask for the application of the structured, electrically conductive seed layer is not required. Also, their application can be carried out at relatively low temperatures, so that the thermal stress of the component (for example, an amorphous silicon layer in a silicon heterocell or the carrier material of a printed circuit board) is minimized.
• the component for example, an amorphous silicon layer in a silicon heterocell or the carrier material of a printed circuit board
• the metal deposition takes place exclusively or at least predominantly on the structured seed layer.
• the application of a mask on the self-passivating metal or semiconductor or the TCO is not required because of a galvanic deposition on this
• Galvanticians Colour a structure, for example in the form of one or more tracks, obtained, which allows an effective electrical contacting of the electrical component or the formation of an effective circuit structure of a printed circuit board.
• the electrical contacts are in the form of one or more tracks, for example.
• the electrical contacts serve, for example, to dissipate current from the component or to tap voltage from the component or to establish an electrical connection between electrical components that are present on the component.
• the method according to the invention initially comprises the provision of a component which has a front and a rear side, wherein on the front and / or the back side an outer layer of a transparent, electrically conductive oxide (TCO) or a self-passivating metal or Semiconductor is present.
• TCO transparent, electrically conductive oxide
• Semiconductor a self-passivating metal or Semiconductor
• the component is, for example, an electrical component (e.g.
• the component to which the electrical contacts are to be attached may also be the precursor of a printed circuit board.
• the precursor of the printed circuit board preferably contains a plastic (in particular an electrically non-conductive
• Plastic which may optionally be reinforced by fibers, and on this plastic is then preferably the outer layer of the transparent, electrically conductive oxide (TCO) or the self-passivating metal or semiconductor before.
• TCO transparent, electrically conductive oxide
• the precursor of the printed circuit board may for example be a flexible film or alternatively a rigid plate.
• a preferred electrical component is for example a solar cell, a diode (eg a light-emitting diode) or a screen, in particular a
• the front side is the illuminated, i. the radiation source facing side of the component.
• the electrical contacts can be applied, for example, on the front side or on the rear side (for example in the case of an exclusively back-contacted solar cell) or else on both sides of the component.
• the electrical device to which the electrical contact is applied need not yet be in its final form, but usually already contains those components that are essential to its function (such as the realization of the photovoltaic effect).
• the component on which the electrical contact is applied can be a precursor of an electrical component and the other components that are required for the realization of its function are added only after the application of the electrical contact.
• a solar cell is in the context of the present invention
• Semiconductor device understood that shows a photovoltaic effect under the action of radiation energy, usually sunlight.
• the solar cell is a silicon solar cell.
• the component is a heterojunction solar cell, in particular a silicon heterojunction solar cell (SHJ solar cell) or a precursor thereof.
• the solar cell can also be a solar cell contacted exclusively via its rear side.
• the electrical contacts are present, for example, in the form of an interdigital structure.
• the process according to the invention is of particular interest for crystalline
• Silicon solar cell types which at least on one of the two surfaces of a crystalline silicon substrate, which serves as a base material of the solar cell, have a conductive layer whose conductivity must be further improved by metallically applied conductor tracks.
• These include, for example, solar cell types which have on at least one side of the crystalline silicon acting as the base material an optically transparent, electrically conductive coating which suppresses the recombination of electron-hole pairs on the correspondingly coated surface of the crystalline silicon wafer.
• the passivating layers consist of amorphous silicon.
• the surface may also consist of a tunable (and thus also perpendicular to the layer also conductive) silicon dioxide layer on which subsequently a conductive polysilicon layer, a silicon carbide layer or a conductive metal oxide such as e.g. Molybdenum oxide, tungsten oxide, nickel oxide or titanium oxide is applied.
• a highly conductive TCO layer for example an ITO layer
• metallic conductor tracks must additionally be applied to the surface.
• the inventive method is suitable outstanding because it does not require a high-temperature step for sintering the applied metal layers and can be dispensed with organic masks.
• SHJ solar cells are commercially available or can be prepared by methods known to those skilled in the art.
• TCO transparent, electrically conductive oxide
• the class of TCOs and the use of TCO layers for semiconductor devices are known to those skilled in the art, see e.g. Clark I. Bright, Chapter 7 ("Review of Transparent Conductive Oxides (TCO)") in 50 Years of Vacuum Coating Technology and the Growth of the Society of Vacuum Coaters, eds .: Donald M. Mattox and Vivienne Harwood Mattox, Society of
• the TCO layer already exists in these electrical components as the outermost layer ("outer layer") of the component In these cases, it is possible within the scope of the method to directly deposit the electrically conductive seed layer (eg in the form of one or more strip conductors) to apply this TCO outer layer of the electrical component.
• the electrically conductive seed layer eg in the form of one or more strip conductors
• Exemplary TCOs for the TCO outer layer are indium tin oxide ("ITO"), aluminum-doped zinc oxide (AZO), fluorine-doped tin oxide (“FTO”), boron-doped zinc oxide or hydrogen-doped indium oxide TCO coatings can be obtained, for example, by physical or chemical vapor deposition.
• ITO indium tin oxide
• AZO aluminum-doped zinc oxide
• FTO fluorine-doped tin oxide
• boron-doped zinc oxide or hydrogen-doped indium oxide TCO coatings can be obtained, for example, by physical or chemical vapor deposition.
• the TCO layer usually has a sheet resistance at 25 ° C., as determined by the four-point method, in the range of 10 ⁇ to 1000 ⁇ , more preferably 50 ⁇ up to 300 ⁇ .
• the TCO layer preferably has this sheet resistance over its entire area.
• TCO layers have a relatively low sheet resistance, the electrodeposition of common metals such as copper on such TCO layers such as an ITO layer is inhibited compared to the deposition on nobler metal surfaces, especially at low applied voltage.
• the device may comprise an outer layer of a self-passivating metal or semiconductor.
• self-passivating metals or semiconductors are metals or semiconductors which can spontaneously form a passivating, very thin oxide layer in air at room temperature (25 ° C.).
• Suitable self-passivating metals are in particular aluminum, titanium, nickel, chromium or zinc or an alloy of one of these metals.
• a preferred self-passivating semiconductor is silicon.
• a self-passivating metal or semiconductor can be applied to the front and / or rear side of the component, which then already forms the outer layer.
• the component for example a solar cell, in particular an SHJ solar cell
• a layer of a TCO layer can be applied directly to this TCO layer
• self-passivating metal or semiconductor This either forms the outer layer or, alternatively, one or more additional layers of self-passivating metals or semiconductors are applied.
• At least one layer on the TCO layer a non-self-passivating metal (eg copper or silver or a
• Alloy of one of these metals is present and on this non-self-passivating metal layer one or more layers of self-passivating metals or semiconductors are present.
• the metal or semiconductor of the first self-passivating layer is titanium, nickel, Chromium or zinc or an alloy of one of these metals or
• the metal of the second self-passivating layer is aluminum.
• the first self-passivating layer can be applied directly to the TCO layer.
• at least one layer of non-self-passivating metal e.g., copper or silver or an alloy of one of these metals
• the self-passivating aluminum layer can already be the outer layer.
• another layer of a self-passivating metal or semiconductor e.g., titanium, nickel, chromium, or zinc, or an alloy of either of these metals or silicon
• these self-passivating layers can follow one another directly or they can be formed by intermediate layers, for example by so-called diffusion barrier layers (eg palladium layers) or layers of non-self-passivating metals (eg Cu or Ag layers). be separated from each other.
• diffusion barrier layers eg palladium layers
• non-self-passivating metals eg Cu or Ag layers
• a titanium layer and then an aluminum layer are deposited on the TCO layer of the component or a layer of a non-self-passivating metal (eg copper or silver or an alloy of one of these metals) which is present for example on the TCO layer of the component.
• Layer applied, in In this case, the aluminum layer represents the outer layer.
• a titanium layer then apply an aluminum layer and then again a titanium layer, in which case the titanium layer is the outer layer.
• an intermediate layer for example a diffusion barrier layer (for example a palladium layer), may optionally be present between a titanium layer and an aluminum layer.
• the application of a coating of a self-passivating metal or semiconductor on the component can be carried out by known methods.
• Outer layer of the self-passivating metal or semiconductor can
• sputtering also referred to as sputtering
• chemical vapor deposition e.g., plasma assisted vapor deposition PECVD
• attachment of a film of the self-passivating metal or semiconductor may be obtained.
• the component is the precursor of a printed circuit board, then for example a prepreg can be provided on which a film of the
• self-passivating metal preferably an aluminum foil (e.g., glued).
• the front side and / or rear side of the component is preferably coated with at least 50% of its area, more preferably at least 80% of its area, or even over its entire area with the outer layer formed from the TCO or the self-passivating metal or semiconductor.
• the outer layer of the component has a thickness of ⁇ 25 ⁇ , more preferably ⁇ 15 ⁇ , more preferably ⁇ 1.0 ⁇ or even less than 500 nm. If the component is an electrical component, in particular a semiconductor component such as a solar cell or a diode, it may even be preferred that the thickness of the outer layer is not more than 200 nm, more preferably not more than 100 nm, eg 5-100 nm or 5 -50 nm.
• the outer layer has over at least 90% of its area, more preferably over 95% of its area, the above-indicated layer thickness.
• the layer thickness can be determined by conventional methods, for example by microscopic measurement in cross section or cross section.
• a layer of self-passivating metal or semiconductor automatically forms a thin layer of oxide on its surface in air.
• This passivating oxide layer prevents or at least inhibits galvanic metal deposition.
• this spontaneous oxide formation may still be assisted by appropriate means (e.g., contacting an oxidizing medium such as ozone) to effect a more uniform formation of the thin oxide layer.
• suitable treatment for example, formation of a passivating nitride or oxynitride surface layer.
• the layer of self-passivating metal or semiconductor apart from the oxide formation in air due to the self-passivation, optionally supported by treatment with ozone or UV illumination at temperatures below 200 ° C, no other chemical modification before application of the
• Germ layer is subjected.
• the contact resistance (at 25 ° C) between the TCO layer or the layer of self-passivating metal or semiconductor and the seed layer applied thereon should be less than 50 m 2 , more preferably less than 10 mD cm 2 , even more preferably less than 5 m ⁇ cm 2 or less be mD.cm 2 .
• the contact resistance can be determined via the transfer line method (also referred to as transfer length method or transfer length measurement). In this method, the measurement of contact resistance is performed using a suitable test pattern.
• transfer line method also referred to as transfer length method or transfer length measurement
• the method according to the invention comprises applying a patterned, electrically conductive seed layer on defined regions of the outer layer (i.e., the layer of the transparent, electrically conductive oxide (TCO) or the layer of the self-passivating metal or semiconductor), wherein the application of the outer layer (i.e., the layer of the transparent, electrically conductive oxide (TCO) or the layer of the self-passivating metal or semiconductor), wherein the application of the outer layer (i.e., the layer of the transparent, electrically conductive oxide (TCO) or the layer of the self-passivating metal or semiconductor), wherein the application of the
• This electrically conductive seed layer is applied via a non-galvanic process, but then serves in a subsequent galvanic
• Deposition step as a substrate for a metal coating.
• seed layer alternatively
• Seed layer English: seed layer denotes a thin layer, which as
• Crystallization germ and adhesion basis for the electrodeposition of a metal acts.
• Seed layer in the form of one or more tracks ie the electrically conductive seed layer is already structured in their arrangement on the outer layer so that it corresponds to the arrangement of the trainees electrical contacts.
• electrodeposition is a process in which the substrate to be coated is contacted with a plating bath, usually containing a salt of the metal to be deposited, and the metal on the substrate by application of an external power source is deposited. As the electrodeposition on a TCO layer or a layer of self-passivating metal or semiconductor is at least inhibited, the application of the seed layer via a non-galvanic deposition takes place.
• the structured seed layer can be single or multi-layered. If the seed layer is multi-layered, it is composed of two or more superimposed layers, wherein each layer can be made of one or more of the following materials and can be obtained by one or more of the following method steps. Adjacent layers preferably have a different composition.
• An application of the seed layer on defined regions of the outer layer takes place, for example, via a printing process, in particular screen printing, inkjet printing, flexographic printing or aerosol printing, a laser transfer process (also referred to as "induced forward transfer” (LIFT)) or an electroless electrochemical deposition (eg zinc deposition by zincate method and / or deposition of chemical nickel) .
• LIFT laser transfer process
• electroless electrochemical deposition eg zinc deposition by zincate method and / or deposition of chemical nickel
• the seed layer contains, for example, one or more metals (eg copper or a copper alloy, a noble metal or a noble metal alloy such as silver or a silver alloy, nickel or a nickel alloy (eg a nickel-vanadium alloy), indium or an indium alloy, tin or one
• metals eg copper or a copper alloy, a noble metal or a noble metal alloy such as silver or a silver alloy, nickel or a nickel alloy (eg a nickel-vanadium alloy), indium or an indium alloy, tin or one
• Tin alloy cobalt or a cobalt alloy
• one or more electrically conductive polymers eg poly-3,4-ethylenedioxythiophene (PEDOT) or a mixture of PEDOT and polystyrene sulfonate (PEDOT: PSS)
• one or more electrically conductive carbon materials eg graphene, graphene, Carbon nanotubes, graphite, carbon black
• electrically conductive polymers eg poly-3,4-ethylenedioxythiophene (PEDOT) or a mixture of PEDOT and polystyrene sulfonate (PEDOT: PSS)
• electrically conductive carbon materials eg graphene, graphene, Carbon nanotubes, graphite, carbon black
• the electrically conductive component of the seed layer may be in the form of, for example, particles (e.g., metal particles or carbon particles). These electrically conductive particles can be in an organic or inorganic
• Embedded support material for example, an organic polymer.
• the organic polymer may be a thermoplastic or, alternatively, a crosslinkable or, after curing, a crosslinked polymer.
• the electrically conductive particles of the seed layer are present in a synthetic resin, which after the application of the seed layer over the
• Curing process e.g., by thermal treatment and / or UV treatment.
• Suitable organic or inorganic support materials for electrically conductive particles which can be used in a printing process are known to the person skilled in the art.
• the seed layer can also be applied by a laser transfer process ("aser Induced Forward Transfer" LIFT) .
• LIFT laser Transfer process
• the seed layer preferably made of nickel, silver or copper (particularly preferably nickel), first applied to a flat transparent substrate, for example by means of physical vapor deposition PVD.
• the substrate is now brought into contact with the outer layer with the seed layer to the outer layer of the component surface, or at least with a distance of less than 1 mm from the
• the seed layer is detached from the substrate by means of laser irradiation and transferred to the outer layer of the component.
• the seed layer can also be applied by an electroless redox reaction or electroless electrochemical deposition.
• Electroless deposition is understood to be a coating process in which the reduction of the metal to be deposited (in contrast to a galvanic deposition) takes place without the use of an external current source.
• Nickel also referred to as "chemico-nickel" and / or zinc (eg via the zincate process) is preferably deposited via the electroless electrochemical deposition
• the outer layer preferably a self-passivating aluminum layer
• electroless deposition of the chemico-nickel layer is then carried out on a zincate solution with zinc-zinc coating and electrolytic solutions for the electroless deposition of electroless nickel are known to those skilled in the art can be generated directly in the electrolyte solution by a chemical reaction, for example, by the reducing agent sodium hypophosphite.
• the electrolyte solution also contains a nickel salt such as nickel sulphate.
• the nickel deposition is autocatalytic.Since phosphorus also stores, e you get a nickel-phosphorus alloy.
• Galvanizing of defined areas of the aluminum layer can take place, for example, by applying the zincate solution with a stamp of defined geometry.
• the seed layer is applied to the outer layer, it may be that as a result of this application (eg by a LIFT process or by electroless zinc and / or chemical nickel), the resulting from the self-passivation thin oxide layer was removed.
• the structured seed layer is preferably produced without using a mask.
• structured seed layer include, for example, the following steps: Applying an electrically conductive metal layer S 1 on the
• an electrically conductive layer S2 on defined regions of the metal layer S1 by a printing process, in particular screen printing, inkjet printing, flexographic printing or aerosol printing, a laser transfer process or an electroless electrochemical deposition (e.g.
• Electroplating step then takes place, as already explained above, a selective metal deposition on the seed layer, while a metal deposition on the exposed TCO layer or self-passivation layer does not take place or is at least inhibited.
• the electrically conductive metal layer S 1 for example, via a
• Gas phase deposition eg, a plasma-assisted vapor deposition PECVD
• the electrically conductive metal layer S1 preferably has a relatively small thickness, for example a thickness in the range of 5-100 nm, more preferably 5-75 nm, more preferably 5-50 nm.
• the electrically conductive metal layer S1 preferably contains one or more of the following metals : Copper or a copper alloy, silver or a silver alloy, tin or a tin alloy, cobalt or a cobalt alloy, nickel or a nickel alloy (eg a nickel-vanadium alloy).
• the metal layer S1 obtained via a vapor deposition can be single-layered or multi-layered.
• a multilayer metal layer Sl For example, it can be obtained by adding two or more
• Gas phase deposits are carried out sequentially.
• the electrically conductive layer S2 therefore contains, for example, one or more metals (for example copper or a copper alloy, a noble metal or a noble metal alloy such as silver or a silver alloy, nickel or a nickel alloy, indium or a)
• metals for example copper or a copper alloy, a noble metal or a noble metal alloy such as silver or a silver alloy, nickel or a nickel alloy, indium or a
• the exposed areas of the metal layer S1 not covered by the layer S2 are removed. This is done by methods known to those skilled in the art,
• the metal is oxidized (i.e., converted into metal cations) and the metal cations dissolve in an adjacent liquid electrolyte.
• electrochemical oxidation by applying a suitable potential, the metal is oxidized (i.e., converted into metal cations) and the metal cations dissolve in an adjacent liquid electrolyte.
• the seed layer has a thickness of ⁇ 20 ⁇ , more preferably ⁇ 8 ⁇ , more preferably ⁇ 2 ⁇ on.
• the minimum thickness of the seed layer is, for example, 100 nm.
• the seed layer preferably has at least 80% of its area, more preferably over its entire area, the above-indicated layer thickness.
• the layer thickness can be determined by conventional methods, for example by microscopic measurement in cross section or cross section.
• the electrodeposited metal is preferably copper or a copper alloy, nickel or a nickel alloy, or a noble metal such as silver or a silver alloy.
• the electrodeposited layers preferably have a layer thickness of 1-100 ⁇ , preferably 1-20 ⁇ , more preferably, 2-15 ⁇ . The layer thickness can be determined by common methods, e.g. by microscopic measurement in cross section or cross section.
• the seed layer is brought into contact with a galvanic bath containing a salt of the metal to be deposited. In the
• Electroplating bath is usually immersed in an auxiliary electrode, e.g. a copper anode ("sacrificial anode”) or a titanium electrode acts as a counterelectrode, and when the seed layer is exposed to a suitable negative (i.e., cathodic) electrical potential, the metal ions are reduced and the metal deposits on the seed layer.
• an auxiliary electrode e.g. a copper anode ("sacrificial anode") or a titanium electrode acts as a counterelectrode, and when the seed layer is exposed to a suitable negative (i.e., cathodic) electrical potential, the metal ions are reduced and the metal deposits on the seed layer.
• the galvanic deposition can be done by means of direct current or by means of pulse current. As will be described in more detail below, by using a pulse current that changes sign, the selective
• Deposition of the metal on the seed layer can be further improved.
• Pulse current which changes sign, has alternating negative (cathodic) and positive (anodic) current pulses.
• the electrodeposition of the metal on the TCO layer or the layer of the self-passivating metal or semiconductor is at least strongly inhibited. For the electrodeposition step, therefore, it is not necessary to protect those regions of the outer layer that are not covered by the structured seed layer by a mask. The areas of the TCO layer or the layer of the self-passivating metal or semiconductor which are still exposed after the application of the seed layer therefore remain unmasked even during the electrodeposition and can come into contact with the electroplating bath.
• the galvanic deposition on the outer layer of the component is at least inhibited, it has been found in the present invention that when a negative electrical potential is applied, the current density at the surface of this outer layer can still be sufficiently high for the deposition of smaller metal crystallites (eg due to a very high degree of conductivity) small thickness of the passivating
• the electrodeposition of the metal takes place by means of pulse current.
• the pulse current method is a time
• the seed layer is subjected to a time-varying potential.
• a pulse current is used which changes sign, i. which has alternating negative (cathodic) and positive (anodic) current pulses. As long as the germ layer with a negative
• FIG. 1 shows, in a microscope photograph in plan view, the surface of an outer layer of a self-passivating metal, on which a strip-like seed layer and on this seed layer an electrodeposited one
• FIG. 2 shows in a microscope image in plan view the surface of an outer layer of a self-passivating metal, on which a strip-like seed layer and on this seed layer a galvanic
• the electrodeposition was carried out using pulse current with alternating cathodic and anodic
• the intervals in which the germ layer is applied with a negative potential can last up to 10 s, but preferably the time is less than 500 ms, more preferably less than 100 ms, more preferably less than 10 ms.
• the intervals of positive potential at the seed layer opposite the electroplating bath are preferably shorter than those
• Intervals of negative potential more preferably less than half as long, most preferably less than a quarter as long.
• a maximum current density amplitude of 1-60 A / cm 2 is given during the intervals in which the seed layer is subjected to a negative potential.
• the maximum current amplitude with respect to the electroplating bath is preferably to be selected to be at most as high as at a positive potential. Particularly preferred is the
• Voltage amplitude (preferably> 2V, more preferably> 5V, more preferably> 9V) at the seed layer opposite the electroplating bath is preferably higher than the cathodic voltage amplitude (preferably ⁇ 3V, more preferably ⁇ 2V, even more preferably ⁇ 1.7V).
• the galvanic deposition of the metal carried out by means of pulse current with alternating sign, it can in the time interval in which the seed layer is subjected to a positive potential, not only to a resolution of metal already deposited, but also to an oxidation of the material
• Outer layer come, especially when the outer layer is a layer of a self-passivating metal or semiconductor such as aluminum or silicon.
• the self-passivation outer layer can be increasingly oxidized. The oxidation progresses inwardly in the self-passivation layer from the surface, and finally, in this layer oxide areas can be obtained which extend over the entire thickness or height of the layer
• the component is a solar cell
• a SHJ solar cell on the front and / or back of an outer layer of a self-passivating metal or semiconductor, preferably aluminum, titanium, nickel, chromium, zinc or silicon, whose thickness is 5-100 nm, more preferably 5-50 is nm, and the electrodeposition by means of pulse current with alternating sign (ie with alternating cathodic and anodic current pulses).
• the duration and amplitude of the cathodic and anodic current pulses are selected so that the self-passivating outer layer forms oxide regions which extend over the entire thickness or height of the
• the layer of self-passivating metal or semiconductor is deposited, for example, by chemical or physical vapor deposition (e.g., CVD such as PECVD or sputtering). If the solar cell is an SHJ solar cell, the outer layer may become
• self-passivating metal or semiconductor on the TCO layer on at least one of the two sides of the SHJ solar cell.
• two or more layers of self-passivating metals or semiconductors are present, the outermost of these layers then representing the outer layer.
• one of the internal layers of self-passivating metal or semiconductor may be directly attached to the TCO layer.
• the seed layer and the seed layer may be directly attached to the TCO layer.
• the accumulated charge flowing during the anodic pulses is smaller than the accumulated charge flowing during the cathodic pulses
• the summed charge which flows during the anodic pulses is greater than the summed charge which flows during the cathodic pulses
• Seed layer and the oxidation of the exposed areas of the outer layer can be further improved.
• both phases of this pulse current treatment can take place during the electrodeposition of the metal in the electroplating bath.
• the first phase of the pulse current treatment takes place during the electrodeposition of the metal in the electroplating bath, then the seed layer and the exposed areas of the outer layer of the
• Electroplating be transferred into an anodizing and the second phase of the pulse stream treatment is carried out in the anodizing.
• Anodization of the self-passivating metal (e.g., aluminum) or semiconductor in an anodizing bath is an electrolytic process for producing or reinforcing oxide layers on metals or semiconductors.
• Suitable anodizing baths include e.g. Sulfuric acid, oxalic acid, citric acid or chromic acid.
• the anodization is carried out using a pulse current with alternating cathodic and anodic pulses. Since a certain dissolution of the already electrodeposited metal takes place during the anodization during anodic voltage application, the anodization bath inevitably also contains metal ions, preferably metal ions are additionally added to the bath by adding a corresponding metal salt and / or using a counterelectrode from the corresponding metal in the bath , When the anodization is pulsed, the cathodic pulses can thus be used for the deposition of the metal.
• the accumulated charge that flows during the anodic pulses is greater than the accumulated charge that flows during the cathodic pulses.
• the galvanic metal layer grows on the seed layer and the anodic pulses prevent the parasitic deposition on the remaining outer layer in this phase.
• the anodization bath in the regions in which the outer layer does not have a seed layer with a galvanic layer deposited thereon, there is an increased conversion of the outer layer into a corresponding oxide layer.
• the charge flowing during the anodic pulses may be calculated from the integral of the current over time during which the device is subjected to anodic potential. Accordingly, the charge flowing during the cathodic pulse can be discharged from the Integral of the current over the time during which the component is subjected to cathodic potential can be calculated.
• Figure 3a shows schematically in cross section a SHJ solar cell 1, a thin
• the outer layer 2 can
• the self-passivating is preferably applied by PECVD and preferably has a thickness in the range of 5-100 nm, more preferably 5-50 nm.
• the self-passivating is preferably performed by PECVD and preferably has a thickness in the range of 5-100 nm, more preferably 5-50 nm.
• Outer layer 2 is present on the TCO layer (not shown in FIG. 1a) of the SHJ solar cell. Alternatively, between the TCO layer and the
• an SHJ solar cell 1 has already been described in more detail above and is therefore not shown in detail in FIG. 3 a.
• a very thin passivating oxide film (not shown) inevitably forms on the surface of the self-passivating outer layer 2.
• a suitable method for example a printing method such as screen printing, inkjet printing or aerosol printing, a laser transfer method or an electroless electrochemical deposition
• an electrically conductive seed layer is applied to defined regions of the self-passivating outer layer 2.
• the seed layer 3 contains, for example, an or several metals (eg copper or a copper alloy, nickel or a nickel alloy, indium or a Indium alloy, tin or a tin alloy, a noble metal such as silver or a silver alloy, zinc or a zinc alloy, chromium or a chromium alloy, cobalt or a cobalt alloy), one or more electrically conductive polymers (eg poly-3,4-ethylenedioxythiophene (PEDOT) or a mixture of PEDOT and polystyrene sulfonate (PEDOT: PSS)), one or more electrically conductive
• an electrically conductive polymers eg poly-3,4-ethylenedioxythiophene (PEDOT) or a mixture of PEDOT and polystyrene sulfonate (PEDOT: PSS)
• Carbon materials e.g., graphene, graphene oxide, carbon nanotubes, graphite, carbon black
• a mixture of at least two of these components e.g., graphene, graphene oxide, carbon nanotubes, graphite, carbon black
• the electrodeposition of a metal 4 then takes place on the seed layer 3 using a pulse current with cathodic (negative) and anodic (positive) current pulses.
• the structure thus obtained is shown schematically in FIG. 3b.
• the seed layer 3 and the exposed areas of the outer layer 2 were brought into contact with a galvanic bath.
• the presence of the outer layer 2 protects the sensitive TCO layer of the SHJ solar cell from the chemically aggressive electroplating bath.
• the seed layer 3 was subjected to an electrical potential, which periodically changes its sign.
• the deposition of the metal 4 takes place predominantly only on the seed layer 3, since the galvanic metal deposition is inhibited on the passivated surface of the outer layer 2. In the context of the present invention, however, it was recognized that a small
• Metal deposition also takes place on the passivated surface of the outer layer 2. By using a pulse current with a different sign, these parasitic metal deposits on the exposed areas of the outer layer 2 can be largely dissolved again. In addition, in the exposed areas of the outer layer 2 which are therefore in contact with the electroplating bath, oxidation of the metal or semiconductor progressing from outside to inside occurs. Finally, oxide layers 5 which extend over the entire thickness of the outer layer 2 are formed in the outer layer. The regions of the outer layer 2 which lie below the seed layer 3 remain metallic or semiconductive. The result is a coating 7 which is a lateral one Has structuring in which oxidized regions 5 and metallic or semiconductive regions 6 alternate. The seed layer 3 is present on the metallic or semiconducting regions 6 of the laterally structured coating 7 and is completely covered by the electrodeposited metal layer 4. Due to the small thickness, the oxide regions 5 are transparent. unnecessary
• the method can be performed without using a mask. A significant thermal load of the component is avoided.
• these exposed areas of the outer layer after the electrodeposition of the metal by a
• etching treatment removes etching treatment.
• recesses ie, solid-free areas
• it can be used to produce electrical contacts with an interdigital structure, as required for the back-side contact of solar cells.
• it may be preferable to carry out the previously occurring electrodeposition using pulsed current with alternating sign in order to minimize parasitic metal deposits in the exposed regions of the outer layer.
• the duration and amplitude of the anodic and cathodic current pulses are preferably chosen such that oxidation of the outer layer is kept as low as possible (eg only at the surface of the outer layer, but not deeper oxidation). As a result, the individual tracks remain electrically connected. This is advantageous because so all the tracks in the
• the exposed areas of the outer layer are treated with an etching bath.
• the outer layer is thereby removed in these areas.
• areas of self-passivating metal or semiconductor, on which there is a seed layer with electrodeposited metal coating and between these areas of self-passivating metal or semiconductor, remain on the component (e.g., the solar cell or the precursor of the circuit board)
• Recesses ie solids-free areas
• a lateral structuring is produced in the outer layer.
• Suitable etching baths are known to the person skilled in the art (for example basic or acid etching baths).
• the component is subjected to a negative voltage relative to the etching bath. This may be particularly advantageous if the component, in particular a solar cell such as a SHJ solar cell, a TCO layer (eg, an ITO layer) contains and this TCO layer is to be exposed by the treatment in the etching bath. Due to the negative voltage application of the component with respect to the etching bath, corrosive damage to the TCO layer is avoided or at least significantly reduced. The amount of negative voltage may vary depending on the metals to be removed in the etching bath.
• the component is compared with the etching bath with a negative
• Voltage of 0.2-1.5 V more preferably applied 0.5-1.0 V, especially when it comes to the metals to be removed in the etching bath to aluminum and / or titanium.
• the self-passivation outer layer may be directly on the TCO layer, or alternatively one or more additional layers may be interposed between the TCO layer
• self-passivation outer layer and the TCO layer are present. If an etching treatment is carried out and if one or more additional layers are present between the self-passivating outer layer and the TCO layer, these additional layers are preferably likewise removed by the etching treatment so that the TCO layer of the SHJ solar cell is at least partially exposed.
• FIG. 1 An exemplary structure in which the lateral structuring takes place by forming recesses between the regions 6 of the self-passivating metal or semiconductor remaining after the etching treatment is shown in FIG.
• the electrically conductive seed layer 3 is present on the remaining areas 6, the electrically conductive seed layer 3 is present. This electrically conductive seed layer 3 is covered by the electrodeposited metal layer 4.
• the regions 6 are preferably located directly on the TCO layer of the SHJ solar cell 1.
• the TCO layer is thus preferably at least partially exposed by the etching treatment. If, during the manufacturing process, the self-passivation outer layer has been applied directly to the TCO layer of the solar cell, the regions 6 consist of this self-passivating metal or semiconductor. If several layers were applied to the TCO layer of the solar cell, also each of the areas 6 has a corresponding one
• the uppermost layer of a region 6 in this case is formed by the metal or semiconductor of the self-passivation outer layer and is in direct contact with the seed layer.
• Galvanic bath with a potential with periodically changing sign can be realized by measures that are known in the art.
• the operational amplifier OP1 controls with its output the push-pull stage, consisting of the npn (Darlington) transistor Tl and the pnp (Darlington) transistor T2 to.
• the differential amplifier OP2 which measures the voltage drop across the shunt resistor Rsh, is attenuated via an RC element (Cl, Rl, R2) fed back to the inverting output of OP1.
• the Shunt resistance thus results in the amplitudes of the current through the workpiece, unless the voltages V + and V- have a limiting effect.
• the voltage V + is chosen so high that the predetermined current is reached.
• the use of a self-passivation outer layer results in most of the electrodeposition on the seed layer and not on the exposed (i.e., non-seeded) regions of the self-passivation outer layer. Even if the self-passivation outer layer has a defect or is damaged before the electrodeposition, a thin one automatically forms again
• a non-self-passivating metal layer (eg Cu or Ag) is applied to the component.
• a thin dielectric layer is subsequently applied to this non-self-passivating metal layer, for example by oxidation of the metal surface or by applying a separate dielectric material such as Al 2 O 3 or SiO 2 (eg by sputtering).
• This is followed by the application of a structured seed layer via a non-galvanic process step and the electrodeposition of a metal on the seed layer.
• the dielectric layer is defective, this defect is not automatically cured by the underlying non-self-passivating metal. In galvanic treatment, therefore, not only does metal deposition occur on the structured seed layer, but also significant amounts of the metal are deposited in the area of the defect.
• the present invention also relates to an apparatus obtainable by the method described above.
• the present invention also relates to a device containing
• a component having a front side and a rear side, wherein on the front side and / or the back side of the component there is a laterally structured coating which has metal or semiconducting regions of a self-passivating metal or semiconductor at defined intervals,
• a galvanically deposited metal layer that covers the seed layer, preferably completely covered.
• the component is for example an electrical component (eg an optoelectronic component or a semiconductor component, in particular a solar cell) or a preliminary stage of a printed circuit board.
• a preferred electrical component is for example a solar cell, a diode (eg a light emitting diode) or a screen, in particular a flat screen ("Fiat Panel Display"), eg a liquid crystal screen "LCD”.
• the front side is the illuminated side, ie the side of the component facing the radiation source.
• a particularly preferred solar cell is an SHJ solar cell.
• oxidic regions may be present between the metallic or semiconducting regions.
• the oxidic regions preferably extend over the entire thickness or height of the laterally structured coating.
• the oxide region is formed by an oxide of the self-passivating metal or semiconductor (e.g., an alumina or a silica).
• metallic or semiconductive regions and oxide regions alternate in the lateral direction.
• Electroplating come into contact, there is essentially no oxidation and the metallic or semiconducting structure is retained in these areas.
• oxidic areas may be in the laterally structured
• a recess ie a solid-free area
• these recesses result from an etching step, which is carried out after the electrodeposition of metal.
• the recess has a depth corresponding to the thickness of the
• the laterally structured coating preferably has a thickness of not more than 200 nm, more preferably not more than 100 nm, e.g. 5-100 nm or 5-50 nm, on.
• the laterally structured coating preferably has the abovementioned layer thickness over at least 90% of its area, more preferably over 95% of its total area.
• the layer thickness can be over common
• the metallic or semiconducting regions of the laterally structured coating may, for example, have a width in the range from 10 .mu.m to 80 .mu.m, more preferably 10 .mu.m to 50 .mu.m, and may be present, for example, at intervals of 0.5 mm to 2.5 mm ,
• self-passivating metals or semiconductors are metals or semiconductors which spontaneously form a passivating, very thin oxide layer in air at room temperature (25 ° C.).
• Suitable self-passivating metals are in particular aluminum, titanium, nickel, chromium or zinc or an alloy of one of these metals.
• the self-passivating metal may be in elemental form or in the form of an alloy.
• a preferred self-passivating semiconductor is silicon. In the oxide regions there is an oxide of the self-passivating metal or semiconductor.
• two or more layers of self-passivating metals or semiconductors and / or at least one layer of a non-self-passivating metal are applied under the
• the metallic or semiconducting regions of the laterally structured coating may contain two or more self-passivating metals or semiconductors and / or one or more non-self-passivating metals.
• the metallic or semiconductive regions then have a layer structure and the uppermost layer, which is in direct contact with the seed layer, contains the metal or the semiconductor of the self-passivation outer layer.
• the metallic or semiconductive regions contain at least a first layer of Ti, Ni, Cr or Zn or an alloy of one of these metals or Si and a second layer of Al, one of these layers being in direct contact with the seed layer.
• one or more layers of non-self-passivating metal e.g., Cu, Ag, or Pd
• non-self-passivating metal e.g., Cu, Ag, or Pd
• the metallic or semiconducting regions of the laterally structured coating can be present, for example, on a TCO layer and be separated from one another either by recesses (as a result of an etching treatment) or by oxide regions (as a consequence of the pulsed current treatment) / or post-treatment in one
• the device is an SHJ solar cell containing a TCO layer (e.g., an ITO layer), the laterally structured one
• Coating on the TCO layer is present, in the laterally structured
• Recesses are present and the recesses extend over the entire thickness of the laterally structured coating, so that the TCO layer is exposed in the areas of the recesses.
• the seed layer is present essentially only on the metallic or semiconducting regions, but not on the oxide regions.
• the surface of the oxide regions is substantially neither with the electrically conductive seed layer nor with the electrodeposited
• the laterally structured coating preferably has a thickness of ⁇ 25 ⁇ m, more preferably ⁇ 10 ⁇ m, even more preferably ⁇ 1.0 ⁇ m.
• the layer thickness can be over common
• Method can be determined, e.g. by microscopic measurement in cross section or cross section.
• the device contains an electrically conductive seed layer which is present on the metallic or semiconducting regions of the laterally structured coating.
• the seed layer contains, for example, one or more metals (eg copper or a copper alloy, a noble metal or a noble metal alloy such as silver or a silver alloy, nickel or a nickel alloy (eg a nickel-vanadium alloy), indium or an indium alloy, tin or a tin alloy, cobalt or a cobalt alloy), one or more electrically conductive polymers (eg poly-3,4-ethylenedioxythiophene (PEDOT) or a mixture of PEDOT and
• metals eg copper or a copper alloy, a noble metal or a noble metal alloy such as silver or a silver alloy, nickel or a nickel alloy (eg a nickel-vanadium alloy), indium or an indium alloy, tin or a tin alloy, cobalt or a cobalt alloy
• electrically conductive polymers eg poly-3,4-ethylenedioxythiophene (PEDOT) or a mixture of PEDOT and
• PEDOT Polystyrenesulfonate
• Carbon materials e.g., graphene, graphene oxide, carbon nanotubes, graphite, carbon black
• a mixture of at least two of these components e.g., graphene, graphene oxide, carbon nanotubes, graphite, carbon black
• the electrically conductive component of the seed layer can be present for example in the form of particles (eg metal particles or carbon particles). These electrically conductive particles may be embedded in an organic or inorganic carrier material, for example an organic polymer.
• the organic polymer may be a thermoplastic or, alternatively, a crosslinkable or, after curing, a crosslinked polymer.
• the electrically conductive particles of the seed layer are present in a synthetic resin, which after the application of the seed layer over the
• Curing process e.g., by thermal treatment and / or UV treatment.
• Suitable organic or inorganic carrier materials which can be used in a printing process are known to the person skilled in the art.
• a seed layer of electrically conductive particles which are embedded in an organic or inorganic carrier material can be applied particularly advantageously via a printing process.
• the seed layer may be formed by a zinc layer (for example via a zincat treatment carried out locally) and a layer of chemical nickel applied to this zinc layer.
• a thin oxide layer can be present between the metallic or semiconductive regions of the laterally structured coating and the seed layer applied thereon.
• this thin oxide layer may be process-removed during application of the seed layer (e.g., by a LIFT process) in these regions, it is also possible for the metallic or semiconducting regions and the seed layer deposited thereon to be immediately adjacent to one another.
• the electrically conductive seed layer is preferably in the form of one or more tracks.
• the seed layer has a thickness of ⁇ 20 ⁇ , more preferably ⁇ 8 ⁇ , more preferably ⁇ 2 microns.
• the minimum thickness of the seed layer is, for example, 100 nm.
• the seed layer preferably has at least 80% of its area, more preferably over its entire area, the above-indicated layer thickness.
• the layer thickness can be determined by conventional methods, for example by microscopic measurement in cross section or cross section.
• the structured seed layer can be single or multi-layered. If the seed layer is multi-layered, it is made up of two or more superimposed layers, wherein each layer can be made of one or more of the above-mentioned materials.
• a multilayer seed layer includes, for example, an electrically conductive metal layer resulting from vapor deposition, and an electrically conductive layer deposited thereon over
• the device also includes a galvanic
• the deposited metal layer covering the seed layer is deposited metal layer covering the seed layer.
• the seed layer completely covered by the electrodeposited metal layer, including the flanks, which laterally delimit the seed layer.
• the complete coverage of the seed layer with the electrodeposited metal is advantageous, since thereby the seed layer in the finished product from oxidation,
• the electrodeposited metal is preferably copper or a copper alloy, nickel or a nickel alloy, or a noble metal such as silver or a silver alloy.
• the device is obtainable via the method described above.
• the present invention also relates to a device containing
• a component having a front and a back, wherein the
• Front side and / or the back of the component is formed by a coating of a transparent conductive oxide (TCO coating),
• a galvanically deposited metal layer that covers the seed layer, preferably completely covered.
• the electrically conductive seed layer and the electrodeposited metal layer reference may be made to the above statements.
• the component is preferably an electrical component (for example an optoelectronic component or a semiconductor component, in particular a solar cell).
• a preferred electrical device is, for example, a solar cell, a diode (e.g., a light emitting diode), or a display screen, particularly a flat panel display ("Fiat Panel Display"), such as a liquid crystal "LCD" screen.
• a solar cell the front side is the illuminated, i. the radiation source facing side of the component.
• a particularly preferred solar cell is an SHJ solar cell.
• the surface of the TCO coating is not substantially covered by the electrodeposited metal layer.
• Example 1 Application of electrical contacts on a carrier material made of plastic for producing a printed circuit board
• a silver particle-containing paste with a volatile solvent with the pattern of the desired printed conductors is applied to the aluminum layer by screen printing. The workpiece is then heated at 100 ° C for 5 minutes to expel the solvent from the paste. Thus, a structured, electrically conductive seed layer is obtained on defined regions of the outer layer.
• a sulfuric copper electrolytic bath with a Cu sacrificial anode the patterned seed layer and the aluminum layer are exposed to a periodically varying potential (ie, use of a pulse current with cathodic (negative) and anodic (positive) current pulses).
• a galvanic deposition of the copper takes place on the seed layer.
• copper crystallites also deposit on the passivated surface of the aluminum outer layer.
• anodic potential there is to some extent a dissolution of the already deposited copper. However, this primarily concerns the copper deposited on the passivated aluminum surface, while the dissolution of copper in the area of the seed layer does not significantly affect the weight.
• the amplitude of the cathodic current density is 10A / dm 2 .
• the area for the current density refers to the area of the seed layer.
• the amplitude of the anodic current density is also 10 A / dm 2 , but based on the total area.
• Aluminum layer i.e., the areas of the aluminum layer not covered by the metal-coated seed layer
• the etching medium is chosen so that the electrodeposited copper layer is far less strongly etched than the aluminum surface.
• the component used is a conventional SHJ solar cell with an edge length of 156 mm x 156 mm.
• this SHJ solar cell already has an ITO layer on its front side.
• the ITO layer acts as the outer layer of the component on which the electrical conductors are to be applied.
• the ITO layer has a sheet resistance of 100 ⁇ across its entire surface.
• ITO is a highly doped electron conductor, ie the conduction band is partially occupied by electrons, while there are virtually no holes in the valence band.
• the chemical potential of ITO is about -4.3 eV.
• the chemical potential of a copper electrolyte is significantly lower (about -5 eV to -6 eV). This results in the transfer of electrons from the ITO surface into the electrolyte when ITO contacts a copper electrolyte. This causes an electrical potential difference between ITO and electrolyte. Because the Charge carrier density in the electrolyte is significantly higher than in ITO, only a small part of the potential in the electrolyte falls on a stretch of a few
• a silver-particle-containing paste with the pattern of the desired printed conductors is applied to the ITO layer by screen printing.
• a structured, electrically conductive seed layer is obtained on defined regions of the ITO outer layer.
• the solar cell is now wetted on the front wetted by a galvanic bath with a Kupferelelektrolyten moves while on the back of a metal loop contact. Since in the example chosen the phosphorus doped amorphous
• Silicon layer of the SHJ solar cell is located on the front, the solar cell is illuminated through the electrolyte bath, so that the electric current can reach the front of the solar cell with cathodic voltage application on the back.
• the solar cells are now subjected to periodic alternating changes for about 5 min for 4 ms cathodically and for 1 ms anodically with voltage.
• the current is limited to 500 mA, the voltage to 2V, at anodic
• Example 3 Application of Electrical Circuits on a Bifacial Silicon Heterojunction Solar Cell
• An SHJ solar cell which has an ITO layer on both its front and back surfaces.
• an aluminum outer layer with a thickness of about 20 nm is applied by sputtering.
• a seed layer of nickel in the form of the electroplated grid is applied by laser transfer.
• a structured, electrically conductive seed layer is obtained on defined regions of the aluminum outer layer.
• the structured nickel seed layer is applied to both the front and the back of the device.
• the SHJ solar cell is now in the areas of the seed layer using
• Stainless steel brackets electrically contacted and completely immersed in a sulfuric acid electroplating bath containing a copper salt.
• the solar cell is then charged periodically for about 5 minutes periodically for 9 ms cathodically and for 1 ms anodic with voltage.
• a current of 800 mA flows when anodic application, a maximum current of 1600 mA and a maximum voltage V + of 10V is specified. This is regulated by the circuit explained above and shown in FIG.
• the first is the galvanic
• the pulse parameters are finally adjusted for complete oxidation of the aluminum layer:
• the amplitude of the andodic current is set to 5 A and the voltage to 10 V.
• the duration of the pulse is 5 ms.
• the amplitude of the cathodic voltage is set to 0.9 V and that of the current to 2 A.
• the duration of the anodic pulse is also 5 ms.
• An insulating silicon oxide layer is applied to the silicon surface.
• an aluminum outer layer of thickness 1 ⁇ is vapor-deposited over the entire surface of the silicon oxide layer. This gives a component with an outer layer of self-passivating metal.
• the aluminum outer layer is contacted via a sealing stamp with a zincate solution. In these areas it comes to
• FIG. 6a shows an SEM image of this surface after the formation of the zinc layer.
• nickel chemical nickel
• FIG. 6b shows a REM
• a structured seed layer is obtained, which is formed by a zinc layer and a nickel layer deposited on this zinc layer.
• the component is brought into contact with a galvanic bath containing a Kupferelelektrolyten. Subsequently, voltage is applied periodically to cathodic and anodic. Copper is electrodeposited on the Zn / Ni seed layer.
• Figure 6c shows a SEM image of the surface after the electrodeposition of the copper. On the self-passivating aluminum Outside layer, no deposition of copper is visible. Subsequently, the component is brought into contact with a galvanic bath with silver electrolyte and using a pulse current with alternating signs, the galvanic deposition of silver on the copper layer takes place.
• the Zn / Ni seed layer is selective on the aluminum regions, which in turn is completely covered by galvanically deposited copper and silver, ie also on the flanks which bound the layer laterally.
• a zincate-based paste is printed locally, which is applied for 80 seconds and then rinsed off with water.
• the substrate is then immersed for 180 seconds in a currentless electroless nickel-phosphorus electrolyte having a pH of 4.8. Only the areas coated with nickel-phosphorus, which were previously affected by the zincate-based paste, will be coated. On defined areas of the aluminum outer layer, a seed layer formed from zinc and chemical nickel is thus obtained. Subsequently, the galvanic deposition of copper takes place on this
• Germ layer of zinc and chemical nickel Germ layer of zinc and chemical nickel.
• an acidic copper electrolyte based on copper sulfate with a pH of 2.8 is used.
• a potential of 1.2 V is applied.
• the negative potential leads to copper deposition on the nickel-phosphorus areas.
• silver electrodeposition from an alkaline silver electrolyte (pH 10.5) only the copper area is coated and the aluminum areas are protected by the applied potential of 1.1V. Subsequently, an etching step is carried out in a dilute hydrochloric acid solution. The aluminum areas are next to the galvanically applied
• Conductors preferably etched.
• the aluminum etching rate is significantly higher than for substrates with comparable thick aluminum layers. The reason for this is the formation of a local element between aluminum and the electrodeposited Ni / Cu / Ag layer stack, resulting in faster dissolution (corrosion) of the aluminum.
• Example 6 Two-sided strip conductors on printed circuit board substrate
• Base substrate for this example is a printed circuit board precursor consisting of prepreg material (layer thickness 500 ⁇ ) which is coated on both sides with an aluminum foil (30 ⁇ ). On both sides are defined areas of the prepreg material (layer thickness 500 ⁇ ) which is coated on both sides with an aluminum foil (30 ⁇ ). On both sides are defined areas of the prepreg material (layer thickness 500 ⁇ ) which is coated on both sides with an aluminum foil (30 ⁇ ). On both sides are defined areas of the
• Aluminum outer layer applied by means of laser transfer process thin nickel layers. These are galvanically reinforced in an alkaline pyrophosphate-based copper bath (pH 8.0). After a layer thickness of 5 ⁇ copper has been deposited, the aluminum is diluted in a
• Example 7 Sodium hydroxide solution is removed from the nickel / copper areas are not attacked. As soon as the aluminum foil has been etched through the entire layer thickness, the Al / Ni / Cu conductor tracks are electrically separated from one another.
• Example 7 Sodium hydroxide solution is removed from the nickel / copper areas are not attacked. As soon as the aluminum foil has been etched through the entire layer thickness, the Al / Ni / Cu conductor tracks are electrically separated from one another.
• a 15 nm thick Ti layer i.e., a first layer of self-passivating metal
• Adhesive layer and diffusion barrier applied. On it is also applied by sputtering an 85 nm thick Al layer.
• This second layer of self-passivating metal represents the outer layer, on which then the structured, electrically conductive seed layer via a non-galvanic
• the electrodeposition step is performed after the seed layer has been applied, the distribution of current in the electroplating process is improved when at least one of the layers of self-passivating metal is an aluminum layer.
• nickel layer in the form of the desired conductor tracks is applied.
• This nickel layer represents the structured, electrically conductive
• the nickel layer is thickened with the aid of the pulse plating method described in Example 3 with a Cu conductive layer and an Ag protective layer.
• the Ti / Al layer stack is etched in the region between the interconnects in 1 molar NaOH.
• a negative voltage of 0.6 V is applied to the workpiece with respect to an auxiliary electrode in the etching bath.

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• 2017
  • 2017-09-12 KR KR1020197010077A patent/KR20190045331A/ko not_active Application Discontinuation
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