WO2005056875A2 - Formation de couches solides sur des substrats - Google Patents

Formation de couches solides sur des substrats Download PDF

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Publication number
WO2005056875A2
WO2005056875A2 PCT/GB2004/005088 GB2004005088W WO2005056875A2 WO 2005056875 A2 WO2005056875 A2 WO 2005056875A2 GB 2004005088 W GB2004005088 W GB 2004005088W WO 2005056875 A2 WO2005056875 A2 WO 2005056875A2
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WO
WIPO (PCT)
Prior art keywords
layer
liquid
substrate
activator
solid layer
Prior art date
Application number
PCT/GB2004/005088
Other languages
English (en)
Other versions
WO2005056875A3 (fr
Inventor
James Edward Fox
Alan Lionel Hudd
Martyn John Robinson
Philip Gareth Bentley
Original Assignee
Conductive Inkjet Technology Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from GB0328221A external-priority patent/GB0328221D0/en
Priority claimed from GB0401825A external-priority patent/GB0401825D0/en
Priority claimed from PCT/GB2004/004589 external-priority patent/WO2005045095A2/fr
Application filed by Conductive Inkjet Technology Limited filed Critical Conductive Inkjet Technology Limited
Priority to JP2006542017A priority Critical patent/JP4881161B2/ja
Priority to KR1020067013540A priority patent/KR101178334B1/ko
Priority to CN200480035925.4A priority patent/CN1898413B/zh
Priority to EP04805916.6A priority patent/EP1689909B1/fr
Publication of WO2005056875A2 publication Critical patent/WO2005056875A2/fr
Publication of WO2005056875A3 publication Critical patent/WO2005056875A3/fr

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Classifications

    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00Apparatus or processes for manufacturing printed circuits
    • H05K3/10Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern
    • H05K3/18Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern using precipitation techniques to apply the conductive material
    • H05K3/181Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern using precipitation techniques to apply the conductive material by electroless plating
    • H05K3/182Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern using precipitation techniques to apply the conductive material by electroless plating characterised by the patterning method
    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23CCOATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C18/00Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
    • C23C18/16Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
    • C23C18/1601Process or apparatus
    • C23C18/1603Process or apparatus coating on selected surface areas
    • C23C18/1607Process or apparatus coating on selected surface areas by direct patterning
    • C23C18/1608Process or apparatus coating on selected surface areas by direct patterning from pretreatment step, i.e. selective pre-treatment
    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23CCOATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C18/00Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
    • C23C18/16Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
    • C23C18/18Pretreatment of the material to be coated
    • C23C18/20Pretreatment of the material to be coated of organic surfaces, e.g. resins
    • C23C18/2006Pretreatment of the material to be coated of organic surfaces, e.g. resins by other methods than those of C23C18/22 - C23C18/30
    • C23C18/2046Pretreatment of the material to be coated of organic surfaces, e.g. resins by other methods than those of C23C18/22 - C23C18/30 by chemical pretreatment
    • C23C18/2053Pretreatment of the material to be coated of organic surfaces, e.g. resins by other methods than those of C23C18/22 - C23C18/30 by chemical pretreatment only one step pretreatment
    • C23C18/2066Use of organic or inorganic compounds other than metals, e.g. activation, sensitisation with polymers
    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23CCOATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C18/00Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
    • C23C18/16Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
    • C23C18/18Pretreatment of the material to be coated
    • C23C18/20Pretreatment of the material to be coated of organic surfaces, e.g. resins
    • C23C18/2006Pretreatment of the material to be coated of organic surfaces, e.g. resins by other methods than those of C23C18/22 - C23C18/30
    • C23C18/2046Pretreatment of the material to be coated of organic surfaces, e.g. resins by other methods than those of C23C18/22 - C23C18/30 by chemical pretreatment
    • C23C18/2073Multistep pretreatment
    • C23C18/208Multistep pretreatment with use of metal first
    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23CCOATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C18/00Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
    • C23C18/16Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
    • C23C18/18Pretreatment of the material to be coated
    • C23C18/20Pretreatment of the material to be coated of organic surfaces, e.g. resins
    • C23C18/2006Pretreatment of the material to be coated of organic surfaces, e.g. resins by other methods than those of C23C18/22 - C23C18/30
    • C23C18/2046Pretreatment of the material to be coated of organic surfaces, e.g. resins by other methods than those of C23C18/22 - C23C18/30 by chemical pretreatment
    • C23C18/2073Multistep pretreatment
    • C23C18/2086Multistep pretreatment with use of organic or inorganic compounds other than metals, first
    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23CCOATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C18/00Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
    • C23C18/16Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
    • C23C18/18Pretreatment of the material to be coated
    • C23C18/20Pretreatment of the material to be coated of organic surfaces, e.g. resins
    • C23C18/28Sensitising or activating
    • C23C18/30Activating or accelerating or sensitising with palladium or other noble metal
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2203/00Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
    • H05K2203/01Tools for processing; Objects used during processing
    • H05K2203/0104Tools for processing; Objects used during processing for patterning or coating
    • H05K2203/013Inkjet printing, e.g. for printing insulating material or resist
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2203/00Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
    • H05K2203/07Treatments involving liquids, e.g. plating, rinsing
    • H05K2203/0703Plating
    • H05K2203/0709Catalytic ink or adhesive for electroless plating
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2203/00Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
    • H05K2203/11Treatments characterised by their effect, e.g. heating, cooling, roughening
    • H05K2203/1157Using means for chemical reduction
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2203/00Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
    • H05K2203/11Treatments characterised by their effect, e.g. heating, cooling, roughening
    • H05K2203/1163Chemical reaction, e.g. heating solder by exothermic reaction

Definitions

  • the invention relates to formation of layers on substrates, particularly, but not exclusively, the formation of conductive metal regions on substrates by the reduction of metal ions.
  • a solid layer of a material on the surface of a substrate there are numerous industrial applications in which it is desirable to form a solid layer of a material on the surface of a substrate.
  • a conductive metal layer in applications as diverse as the manufacture of printed circuit boards, aerials, and antennae such as those found in mobile telephones, radio frequency identification devices (RFIDs), smart cards, contacts for batteries and power supplies, arrays of contacts for flat screen technologies (liquid crystal displays, light emitting polymer displays and the like), electrodes for biological and electrochemical sensors, smart textiles and decorative features.
  • RFIDs radio frequency identification devices
  • smart cards contacts for batteries and power supplies
  • arrays of contacts for flat screen technologies liquid crystal displays, light emitting polymer displays and the like
  • electrodes for biological and electrochemical sensors smart textiles and decorative features.
  • solid in the context of a solid layer, or solid substrate, refers to being in the solid (rather than liquid or gas) phase of matter.
  • a solid layer or substrate may be plastic, elastic, resilient, rigid, gelatinous, permeable or have any other property consistent with being solid phase.
  • the solid layer that is formed covers the surface.
  • the solid layer is patterned, and the accuracy and fineness of detail of the pattern can be important.
  • printed circuit boards may have intricate patterns of copper conductive tracks. Accuracy and fineness of detail is important in determining the extent of miniaturisation possible on such printed circuit boards, and the reliability of the electronic circuits built thereon.
  • Some methods of forming a solid layer on a surface of a substrate require a catalyst, or other activator.
  • the electroless plating process is a solution chemistry plating technique which has been used for many years to apply a conductive metal coating layer to a substrate surface, which can be flat or shaped. In the electroless process, a substrate is immersed in a succession of baths in turn.
  • a plastics substrate is etched in a chromic acid/concentrated sulphuric acid bath at 68 ⁇ 2°C to microscopically etch the surface of the plastics substrate, ensuring good adhesion of the copper to the surface of the plastics substrate.
  • any hexavalent chromic species left on the plastics substance are neutralised in a bath comprising approximately 30% concentrated hydrochloric acid at around 50 °C.
  • the plastics substrate is then added to a third bath in which an activator is added to prepare the plastics substrate surface to absorb the catalyst in the next step.
  • This third bath is typically approximately 30% concentrated hydrochloric acid, at room temperature.
  • the plastics substrate is dipped into a fourth bath, which includes a dilute solution of a palladium colloid along with tin salts.
  • a colloid deposits on the surface of the plastics material to catalyse the deposition of copper in the subsequent plating steps.
  • This bath includes a high proportion of tin salts, approximately 30% concentrated hydrochloric acid, and is operated at room temperature.
  • the fifth bath into which the plastics substrate is dipped includes an accelerator which activates the absorbed palladium, improving the speed and uniformity of deposition.
  • Accelerator baths include around 30% concentrated hydrochloric acid.
  • the activated plastics substrate is dipped into a sixth bath including a plating solution which, catalysed by the palladium colloid on the plastics substrate, causes copper to deposit onto areas of the plastics substrate which were coated with the catalyst.
  • the plating solution includes a copper salt, formaldehyde as a reducing agent, and sodium hydroxide to activate the formaldehyde.
  • the composition of the plating solution must be carefully temperature controlled, with a temperature of 45 + 2°C being appropriate for some commercially applicable compositions.
  • the catalyst is required for formation of the copper layer, and the acid pre-treatment step is important as it helps the resulting metal layer adhere to the substrate.
  • WO 2004/068389 describes a method of forming a conductive metal region on a substrate, comprising depositing on the substrate a solution of a metal ion, and depositing on the substrate a solution of a reducing agent, such that the metal ion and the reducing agent react together in a reaction solution to form a conductive metal region on the substrate.
  • a catalyst or other activator is required to start the reaction which forms the conductive metal region.
  • a catalyst is applied to a substrate surface, which is then brought into contact with the chemical composition which reacts, catalysed by the catalyst, to deposit a metal on the surface of the substrate.
  • a catalyst for a metal-forming reaction it is known to deposit on a substrate, e.g by inkjet printing, a catalyst for a metal-forming reaction, with the catalyst applied in a solution containing a polymeric binder. See, for example, WO 02/099162 which discloses use of binders such as ethyl cellulose.
  • US 6495456 discloses formation of electrodes on a chip substrate by a process that involves applying a photo-active catalyst liquid (of unspecified composition) to a chip substrate, irradiating the substrate with light to activate irradiated portions of the liquid (possibly selectively, e.g. using a mask) and then using electroless plating to form metal on the activated portions. It is known to use ultra violet radiation and other means to reduce palladium acetate deposited on a substrate to palladium metal, followed by electroless plating of copper. Reduction may be performed selectively, by use of a contact mask, to produce patterned catalyst. Alternatively, palladium produced by infra red treatment may be patterned by excimer laser ablation using a metal contact mask.
  • US 3,900,320 discloses a process for metallizing a plastic or ceramic base.
  • a pre-plate solution comprising a compound of catalytic metal, such as a palladium salt, binder material such as one or more polymers and solvent are coated on the base and dried so as to form a thin polymer layer of about 20 Angstrom to about 3000 Angstrom thick which may thereafter be directly plated by contact with an electroless plating solution.
  • the pre- plate solution has specified viscosity characteristics and specified high concentration levels of catalytic metal compound.
  • a photosensitive polymer former can be used as a component of the pre-plate solution specifically for photographically developing a plateable pattern on a substrate such as a circuit board, printing plate or the like.
  • a method of forming, on the surface of a substrate, a first solid layer which is capable of activating a chemical reaction to form a second layer thereon comprising bringing into contact the substrate surface and a first liquid comprising a curable composition and an activator for said second layer- forming chemical reaction; and curing the curable composition to increase adhesion of the material to the surface of the substrate, thereby forming a first solid layer adhered to the surface of the substrate, capable of activating said second layer-forming chemical reaction after contact with a second fluid.
  • a curable composition is one which can undergo a chemical change resulting in hardening, preferably solidification.
  • the hardening process improves adhesion of the material and results in formation of a solid layer (the first solid layer), that may be rigid, plastic, elastic, resilient, gelatinous, permeable or have any other property consistent with being in the solid phase, as opposed to liquid or gas.
  • the solid layer may include regions in liquid or gaseous form.
  • the curable composition is such that the resulting first solid layer adheres to the substrate, and so is selected having regard to the substrate. Adhesion can arise through chemical bonding, physical bonding, mechanical bonding or a mixture thereof. Use of a curable composition can result in improved adhesion to a wider variety of different substrates than is possible with non-curable catalytic solutions of the prior art.
  • the curable composition is brought into contact with the substrate surface while the composition is in liquid form, and is subsequently cured. Curing typically takes place while the curable composition is still in liquid form, although the curable composition may instead be converted to solid form, e.g. by drying, prior to curing.
  • the activator is typically incorporated in the first solid layer, whether by entrapment, immobilisation or other means, and is typically dispersed throughout the first solid layer within a matrix formed by the cured composition. The activator is thus adhered with respect to the substrate by virtue of its inclusion in the first layer.
  • the curable composition typically comprises one or more component chemicals which can undergo a reaction resulting in hardening, preferably solidification.
  • the curable composition comprises one or more monomers and/or oligomers which can polymerise and/or cross-link in use, thereby hardening and forming a solid layer.
  • the resulting product forms a matrix, typically a polymer matrix, which includes the activator.
  • a curable composition including at least some oligomers will often have lower toxicity than if only monomers were included. The presence of at least some oligomers can also result in production of a first layer having improved physical properties such as flexibility, hardness and abrasion-resistance.
  • the curable composition is curable in response to appropriate curing conditions.
  • the composition may be curable in response to a stimulus, such as electromagnetic radiation of a particular wavelength band (e.g. ultra-violet, blue, microwaves, infra-red), electron beams, or heat.
  • a stimulus such as electromagnetic radiation of a particular wavelength band (e.g. ultra-violet, blue, microwaves, infra-red), electron beams, or heat.
  • the composition could instead be curable in response to appropriate chemical conditions, particularly the presence of a chemical curing agent or hardener: in this case a "two pack" approach may be adopted, with one chemical component applied in the first liquid and a second chemical component separately applied (simultaneously or subsequently).
  • the composition may be curable in response to the presence of species such as moisture or air.
  • the curable composition is selected to undergo a reaction responsive to one or more of the above stimuli.
  • An ultra-violet curable composition is currently preferred.
  • first liquid such that no significant or substantial heating is required.
  • the method of the invention can be used with a wide range of substrates, including heat-sensitive plastics materials.
  • the first layer is formed at temperatures below about 300 °C (allowing the use of polyimide substrates), desirably below about 200 °C (allowing the use of polyester substrates such as Teonex (Teonex is a Trade Mark)), more desirably below about 100°C (allowing use of a wide range of themoplastic substrates), yet more desirably below about 50 °C (allowing use of low Tg substrates) and possibly at room temperature, avoiding the need for heating. Heating, if required, is only applied for a relatively short time, typically less than 15 minutes and preferably less than about 2 minutes for processing efficiency.
  • the curable composition comprises one or more monomers and/or oligomers which can form a polymer, and an initiator which starts a polymerisation reaction responsive to a stimulus, as discussed above.
  • Suitable initiators are well known to those skilled in the art.
  • benzoyl peroxide, lauryol peroxide, azobis-(l- hydroxycyclohexane) or AIBN (2,2'-azobisisobutyronitrile) can be included to initiate a polymerisation reaction responsive to heat.
  • Darocur 1173 (2-hydroxy-2-methyl-l-phenyl-propan-l-one), Irgacure 184 (1-hydroxy-cyclohexyl- phenyl-ketone), Irgacure 369 (2-benzyl-2-dimethylamino--l-(4--morpholinophenyl)- butanone-1), Irgacure 651 (2, 2-dimethoxy-l, 2-diphenylethan-l-one), Irgacure 2959 (l-[4- (2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-l-propane-l-one), Irgacure 819 and Irgacure 1700 (Darocur and Irgacure are Trade Marks) are examples of UV photo- initiators, available from Ciba Speciality Chemicals, Manchester, UK and Basel, Switzerland. Typically, such initiators generate free radicals responsive to a stimulus. Other curing processes can be used, such as
  • the monomers and/ or oligomers are those known from the field of UV curable inks, or other curable inks, proposed for inkjet printing of curable inks.
  • Suitable UN-curable materials include acrylates and methacrylates, particularly those included in the following list classified by the number of cross-linkable functional groups:
  • IBOA Isobornylacrylate
  • ODA Octyl decyl acrylate
  • SR484 Caprolactone acrylate e.g. as SR495 Lauryl acrylate, e.g. as SR335
  • Tripropylene glycol diacrylate e.g. as Actilane 424 1,6-hexanediol diacrylate (HDD A), e.g. as Actilane 425 Dipropylene glycol diacrylate (DPGDA), e.g. as SR508 Propoxylated(2) neopentyl glycol diacrylate (PO ⁇ PGDA), e.g. as SR9003 Tricyclodecanedimethanol diacrylate (TCDDMDA), e.g. as SR833S Polyethylene glycol 400 diacrylate (PEG400DA), e.g. as SR344 Trifunctional
  • TMPTA Trimethylol propane triacrylate
  • Actilane 431 Ethoxylated(3) trimethylol propane triacrylate
  • SR454 Ethoxylated(6) trimethylol propane triacrylate, e.g. as SR499
  • Actilane 505 (a tetrafunctional polyester acrylate oligomer) Ethoxylated pentaerythritol tetraacrylate (PPTTA), e.g. as Actilane 440 Ditrimethylolpropane tetraacrylate (di TMPTA), e.g. as Actilane 441
  • DPHA Dipentaerythritol hexaacrylate
  • Actilane range is available from Akzo Nobel, The Netherlands. Actilane is a Trade
  • the SR range is available from Sartomer, USA.
  • All of the above acrylates cure in response to free radicals, e.g. generated from an initiator such as Irgacure 819 and Irgacure 1700. All of the above acrylates are in the form of liquids, although it is instead possible to use solid monomers and/or oligomers.
  • some (but not all) of the monomers and/or oligomers have at least 3 cross-linkable functional groups, e.g. being selected from the trifunctional, tetrafunctional and hexafunctional materials listed above.
  • Use of such materials results in production of polymers that are more highly cross-linked than polymers formed from monomers and/or oligomers with fewer cross-linkable functional groups, and can provide a stronger, more robust film with better adhesion to the substrate. Too high a proportion of such highly cross-linkable monomers and/or oligomers (having at least 3 cross-linkable functional groups) would, however, tend to form a brittle surface and so should be avoided.
  • the method conveniently includes formation of the second layer on the first solid layer.
  • the method thus preferably further comprises bringing into contact the first solid layer and a second fluid that comprises one or more reagents for chemical reaction, activated by the activator, to form the second layer.
  • the second fluid contacts the activator in the first layer, and reacts to form the second layer on the first solid layer.
  • the first solid layer need not necessarily finish curing before the second fluid is applied.
  • the second layer of material is typically solid and is conveniently a conductive metal layer, which may be formed by a variety of different processes involving the activator in the first layer.
  • the processes typically involve the reduction of metal ions, and include electroless plating, as referred to above, and the process disclosed in WO 2004/068389.
  • the improved adhesion of the first layer to the substrate surface results in improved adhesion of such a conductive metal layer, and makes it possible to produce a thicker layer of metal, e.g. copper, without blistering or peeling of the layer from the substrate.
  • the second reaction e.g. metallisation
  • reaction will generally occur on or in the first layer in preference to reaction, e.g. the formation of fine particles of metal, in the second fluid.
  • the second fluid may be in the form of one or more components, that may be applied to the first solid layer simultaneously or sequentially.
  • the first layer need not be directly adhered to the substrate surface: there may be one or more intervening layers. Further, the second layer need not be the top or final layer: one or more further layers may be formed thereon.
  • the method of the invention allows greater choice of substrate for a given second layer, and vice versa, than would otherwise be possible.
  • the second layer may in some cases be more securely affixed with respect to the substrate than if the second solid layer were adhered directly to the substrate. This can allow a greater choice of substrate for a given second layer and/or allows a thicker second layer to be formed than would be the case if the activator were applied by a different technique.
  • the activator is preferably a catalyst, such as palladium for catalysing a metallisation reaction.
  • the activator could instead comprise a chemical species which can activate the second layer forming chemical reaction, but is consumed or reacts in the process, and so is not strictly speaking a catalyst.
  • the activator may alternatively comprise a reagent, or a plurality of reagents which, when brought into contact with a second fluid comprising components (preferably other components) of a second solid-layer-forming chemical reaction, undergo a chemical reaction leading to formation of a second layer on the first solid layer.
  • the activator may be applied in precursor form.
  • the method may include the further step of chemically converting the one or more precursor reagents to an active or catalytic form.
  • palladium acetate may be reduced in situ by a subsequently applied reducing agent solution, forming palladium metal which can catalyse deposition of metal thereon when an appropriate second fluid is applied.
  • the first solid layer may coat most or all of the entire substrate surface.
  • the first solid layer may be formed on the substrate according to a pattern. This may be achieved in several ways.
  • the first liquid may be deposited according to a pattern, e.g. by printing in the desired pattern, particularly by inkjet printing.
  • the first solid layer may be patterned after the first liquid has been deposited; for example, the first liquid may be applied extensively across the substrate, selectively cured according to a pattern and uncured liquid may then be removed.
  • Selective curing according to a pattern can be achieved by use of a mask, such as a shadow mask for liquid or solid layers or a contact mask for solid layers, to limit exposure to a stimulus as discussed above, e.g. UV radiation.
  • Laser writing using a laser of appropriate wavelength for a particular initiator
  • electron beam writing can also be used. With electron beam writing, a photoinitiator is not required, and this approach can be used to create patterns with very fine features, of the order of 10 nm.
  • a curing agent or hardener may be selectively applied according to a desired pattern.
  • excess (uncured) material may be removed by techniques including washing, spraying or immersion in suitable reagents such as an acid, alkali or solvent or by physical means such as use of an air knife.
  • curable composition can allow patterning to an extent which would not be possible were the activator deposited on the substrate as a liquid which remained soft and flowed.
  • the first liquid can be applied extensively to a substrate surface by a wide range of possible techniques, including using printing, dipping, spraying and spinning techniques such as jet printing, inkjet printing, spin coating, dip coating, spray coating, aerosol spraying, roller coating, curtain coating, screen printing, litho printing, flexo printing, gravure printing and pad printing, or by any other liquid application technique.
  • printing, dipping, spraying and spinning techniques such as jet printing, inkjet printing, spin coating, dip coating, spray coating, aerosol spraying, roller coating, curtain coating, screen printing, litho printing, flexo printing, gravure printing and pad printing, or by any other liquid application technique.
  • the first liquid is brought into contact with the substrate by a deposition process, for example a printing process.
  • the deposition process is a non- contact process that is preferably digital e.g. inkjet printing.
  • the first liquid is preferably applied as a single liquid, e.g. by inkjet printing from a single liquid reservoir.
  • Printing processes typically result in production of a first solid layer having a thickness greater than 300 nm and possibly significantly thicker.
  • the first liquid is typically in the form of a solution, preferably a partially or entirely non- aqueous solution, but may alternatively be in the form of a suspension or dispersion with one or more components in solid or colloidal form, or an emulsion. Different ingredients of the first liquid may be present in different forms.
  • the first liquid generally includes a carrier liquid (which may function as a solvent e.g. for the activator), which is preferably partially or entirely non-aqueous. Preferred non-aqueous liquids are discussed below.
  • the carrier liquid may be constituted by one or more curable monomers and/or oligomers, e.g. as discussed above, if in liquid form, or may be constituted by a separate liquid (not part of the curable composition) performing a carrier function only.
  • the second fluid is preferably in liquid form, and so is a second liquid.
  • the second liquid may be in the form of a solution, preferably an aqueous solution, but may alternatively be in the form of a suspension or dispersion with one or more components in solid or colloidal form, or an emulsion.
  • the second liquid thus generally includes a carrier liquid (which may function as a solvent).
  • the carrier liquid of the second liquid preferably comprises water.
  • the first liquid desirably includes a carrier liquid that is sufficiently aggressive to the substrate to allow the first liquid to penetrate therein, with the carrier liquid partially dissolving or otherwise permeating into the substrate, increasing adhesion of the first solid layer to the substrate, and thus also increasing the adhesion of the second layer to the substrate (via the first solid layer).
  • the first liquid and the second liquid preferably comprise different carrier liquids. This allows the carrier liquid of the first liquid to be selected to be appropriate for the formation of the first layer and the adhesion of the first layer to the substrate, whilst the carrier liquid of the second liquid can be selected to be appropriate for the formation of the second layer.
  • the carrier liquid of the second liquid is water.
  • aqueous metallisation chemistry and a non-aqueous first stage can be utilised in different steps of the same process.
  • the carrier liquid of the first liquid is partially or entirely non- aqueous.
  • print quality and adhesion are governed predominantly by the properties of the first liquid and the first solid layer which it forms.
  • the invention allows the first liquid to be selected dependent on the patterning quality required and the second fluid to be selected dependent on the desired properties of the second layer. This can allow greater flexibility in designing appropriate first liquid and second fluid chemistries for a particular application.
  • the first liquid may be selected to have improved wetting properties on one or more substrates as compared with those of the second fluid. This allows more accurate and precise patterning than if the first liquid was applied from the same carrier liquid (e.g. water) as the second fluid, with fine features and better edge definition being possible. There will typically be less bleed and feathering of the first liquid than if activator were applied to the surface by a different technique using a carrier with poorer wetting properties. Improved wetting properties allow more accurate and precise patterning as successive spots of liquid along a line can be deposited further apart (by a technique such as inkjet printing) allowing a lower volume of liquid to be used, and thus narrower lines and finer features to be prepared.
  • carrier liquid e.g. water
  • first liquid comprising an activator is particularly beneficial when using inkjet printing to deposit a material on a substrate.
  • Many curable liquids have an appropriate viscosity to be suitable to be inkjet printed, giving good print head performance. Suitable viscosities for inkjet printing liquids are typically in the range 1 to 20 cPs at print head operating temperature.
  • the process may be repeated (optionally with different first liquids and second fluids) to build up a multi-layer structure.
  • the first solid layer preferably includes a first chemical functionality which is at least partially insoluble in the second fluid, as disclosed in our International Application PCT/GB2004/004589. This means that the physical integrity of the first layer is maintained on contact with the second fluid and while the second layer is formed. This has the consequence of improving adhesion of the second layer with respect to the substrate surface.
  • the first chemical functionality need not be completely insoluble in the second fluid, but merely sufficiently insoluble to achieve this effect. Thus, the first chemical functionality only needs to be sufficiently insoluble in the second fluid to retain the integrity of the first layer while the second layer is formed.
  • the second fluid is preferably aqueous, as noted above, so the first chemical functionality is preferably at least partially insoluble in water.
  • the first chemical functionality may be present in the first liquid, and also in the first layer, or may be formed, e.g. by cross- linking, in the first layer from reactants (that are possibly soluble in the second fluid) in the first liquid.
  • the first chemical functionality is preferably non-ceramic.
  • the first chemical functionality is preferably at least predominantly or fully organic and/or silicon based, comprising at least 50% by weight of organic and/or silicon materials, for improved adhesion to a wide range of organic substrates such as plastics substrates.
  • the first chemical functionality may absorb the second fluid and swell.
  • the first chemical functionality may be constituted by the reaction product of the curable composition, e.g. one or more curable monomers and/or oligomers in the first liquid. Such materials may be included in the first liquid and react to form a polymer in the first layer with appropriate solubility properties.
  • the polymer product also has good adhesion to a very wide range of substrates, including metals, glass, ceramics and plastics materials.
  • the first liquid preferably includes one or more ingredients that constitute or form the first chemical functionality in the first layer.
  • the components of the first liquid are selected so that the first solid layer is permeable to the second fluid when the second fluid is brought into contact with the first solid layer, as disclosed in our International Application PCT/GB2004/004589.
  • this can substantially improve the effective activation/catalytic activity of the first solid layer.
  • the second fluid can penetrate the first solid layer, allowing the second fluid to access the activator within the first solid layer.
  • the second layer- forming reaction can thus take place on, or in close proximity to, the substrate surface, producing the desired second layer of material on the substrate.
  • penetration of the second fluid into the first solid layer may result in the second layer of material intermingling with the first solid layer, thereby enhancing adhesion of the second layer of material to the substrate via the adhered first solid layer and improving through layer conductivity (where the second layer is conductive from its top surface down to the surface of the substrate).
  • the first layer thus preferably comprises a second chemical functionality which is at least partially soluble, miscible or swellable in the second fluid or permeable to the second fluid, as disclosed in our International Application No. PCT/GB2004/004589.
  • the second fluid is preferably aqueous, as noted above, so the second chemical functionality is preferably at least partially soluble or swellable in water or permeable to water.
  • the second chemical functionality may be present in the first liquid, and also the first layer, or may be formed in the first layer from reactants in the first liquid. Suitable second chemical functionalities are discussed below, and include polyvinylpyrrolidone (PVP), which is soluble in water, and which may be included as an ingredient of the first liquid.
  • PVP polyvinylpyrrolidone
  • the second chemical functionality will at least partially dissolve or swell in, or be permeable to, the second fluid, allowing the fluid to penetrate the first solid layer and contact the activator.
  • the first chemical functionality retains sufficient integrity to adhere to the substrate and the second layer, resulting in a "sponge-like" structure. This has the consequence of permitting enhanced access to the activator than would otherwise be the case, allowing the use of lower concentrations of activator, with consequential cost savings.
  • the ability to be able to use relatively low proportions of activator in the first liquid has the benefit of allowing greater freedom in formulation of the first liquid, e.g. in terms of properties such as viscosity and solvent choice.
  • the first liquid may comprise one or more ingredients which constitute or form in the first layer a second chemical functionality which is at least partially soluble, miscible or swelleable in the second fluid or permeable to the second fluid.
  • a second chemical functionality is polyvinylpyrrolidone (PVP), which is soluble in water.
  • PVP polyvinylpyrrolidone
  • Alternatives include poly aery lie acid, poly vinyl acetate, polyethylene imine, polyethylene oxide, polyethylene glycol, gelatin or copolymers thereof.
  • the soluble components may dissolve when the second fluid is brought into contact with the first solid layer.
  • the polyvinylpyrrolidone will dissolve in contact with an aqueous solution of metal ion and reducing agent usable to form a conductive metal region on the first solid layer (see below). Around 5% by weight of polyvinylpyrrolidone in the resulting solid layer is appropriate.
  • the first liquid could instead (or as well) comprise a water swellable monomer and/or oligomer such as HEMA (2-hydroxy ethyl methacrylate), GMA (glyceryl methacrylate) or NVP (n- vinyl pyrrollidinone).
  • HEMA 2-hydroxy ethyl methacrylate
  • GMA glyceryl methacrylate
  • NVP n- vinyl pyrrollidinone
  • the first liquid could instead (or as well) comprise a high boiling point solvent miscible with the second liquid, with the high boiling point solvent remaining in liquid form in the first solid layer.
  • a high boiling point solvent miscible with the second liquid with the high boiling point solvent remaining in liquid form in the first solid layer.
  • NMP n-methyl pyrrolidinone
  • suitable solvents include ethylene glycol, diethylene glycol or glycerol.
  • the first liquid could instead (or as well) comprise micro-porous particles to create a micro-porous film structure.
  • Micro-porous particles could be organic (e.g. PPVP (poly (polyvinylpyrrolidone))) or inorganic (e.g. silica).
  • the weight ratio of the first chemical functionality to the second chemical functionality is preferably greater than about 5:1, more preferably greater than about 10: 1, most preferably greater than about 15: 1.
  • the use of relatively large amounts of the first chemical functionality results in benefits of improved adhesion to the substrate surface, more rapid curing, durability of the resulting first solid layer, and improved formulation flexibility for the first liquid.
  • the first liquid may include a carrier liquid which is volatile and which evaporates off, partially or fully, after application to the substrate.
  • the first liquid may comprise water or (preferably) one or more organic solvents which, in use, are evaporated off before the second fluid is brought into contact with the first layer.
  • the method in this case may include a pause to allow a volatile carrier to evaporate before one or both of applying a stimulus (if applicable) and bringing the second fluid into contact with the first layer. It may be advantageous for some of the carrier liquid to remain in the first solid layer in liquid form, to keep the first layer matrix open.
  • the delay between depositing and curing the first liquid is 20 seconds or less.
  • the curing process itself can be achieved very rapidly, typically in less than 1 second, with benefits of control of image quality.
  • the carrier liquid is constituted by liquid monomers/oligomers, substantially all of the constituents of the first liquid may remain in the first solid layer, albeit possibly in chemically changed form.
  • the activator As the activator is also included in the first liquid, it will typically be trapped within the first layer in a matrix formed, for example, by a polymer.
  • the activator could also be immobilised as part of the matrix, for example, by including the activator on a molecule with a reactive group which reacts with monomer or oligomer units.
  • the activator may be initially inactive, and become active only once the first liquid has been cured, or in response to a stimulus, or when in contact with a component of the second fluid.
  • Conductive metal layers are typically formed by the reduction of metal ions in a reaction involving a catalyst, a metal ion and a reducing agent.
  • a variety of different techniques may be used, including electroless plating and the process disclosed, in WO 2004/068389.
  • One reagent of the process typically the catalyst, is deposited on a substrate (typically by inkjet printing) in the first layer by the method of the invention, and other necessary reagents deposited (by inkjet printing, immersion or otherwise) in the second fluid (and possibly in one or more other vehicles) resulting in reaction to form a conductive metal layer constituting the second solid layer.
  • the activator conveniently comprises a metal or metal-containing material, typically a catalyst or catalyst precursor.
  • Suitable metals include metal colloids or particles, such as colloids or particles of platinum, silver, palladium, iridium, bronze, aluminium, gold or copper.
  • Suitable metal- containing materials include salts or complexes of a conductive metal, preferably salts of a transition metal, particularly palladium, platinum and silver.
  • the salts may be inorganic, such as palladium chloride, or organic, for example palladium acetate or palladium propanoate. Preferred organic salts are alkanoates.
  • the current preferred activator is palladium acetate. Desirably the weight ratio of the curable composition to the metal portion of the activator is greater than about 15:1, preferably greater than about 25:1.
  • a suitable solvent for the deposition of an organic acid salt of a transition metal include diacetone alcohol, a 50/50 mixture of equal parts by weight of diacetone alcohol and methoxy propanol, and a 50/50 mixture of equal parts by weight of toluene and methoxy propanol.
  • a co-solvent is preferably included to increase viscosity to suitable levels for inkjet printing.
  • the salt, e.g. palladium acetate is conveniently present in an amount in the range 1 to 3 % by weight, preferably about 2% by weight of the deposited liquid.
  • the second fluid conveniently comprises a solution of a metal ion and a reducing agent, operable to react together, activated by the activator, to form a conductive metal region on the first solid layer.
  • the composition of the second fluid is such that it does not react spontaneously, but reacts only once it has been brought into contact with the activator present in the first solid layer.
  • the second fluid may further comprise pH-altering reagent such as an acid or a base, to activate the reducing agent.
  • the metal ion, the reducing agent and the optional base/acid may be deposited in two or three separate component solutions which mix together on the substrate to form a reaction solution. Further details may be as disclosed in WO 2004/068389.
  • the activator may be one or more of metal ions, reducing agent or a pH altering reagent such as an acid or base.
  • the second fluid will be such that a second-layer- forming reaction begins when the second fluid is in contact with the first layer.
  • the activator comprises metal ions, typically as metal salts or metal complexes (and perhaps also acid/base)
  • the second fluid may comprise reducing agent, possibly with appropriate pH adjusting reagent, e.g. a base in the case of formaldehyde.
  • the second fluid may also contain additional ions of the same or a different metal.
  • the activator could be metal particles or colloids.
  • the second fluid will preferably comprise metal ions, typically as metal salts or metal complexes.
  • the second fluid may comprise further reducing agent which may be the same or different to the first reducing agent. It may be appropriate to use a more powerful reducing agent such as DMAB (dfmethylamineborane) initially followed by a less powerful reducing agent such as formaldehyde which gives a more pure, higher conductivity metal layer.
  • the activator comprises pH altering reagent
  • the second fluid typically includes metal ions and reducing agent, and optionally further pH altering reagent.
  • the metal ion may be an ion of any conductive metal, particularly a transition group metal.
  • Preferred conductive metals include copper, nickel, silver, gold, cobalt, a platinum group metal, or an alloy of two or more of these materials.
  • the conductive metal may include non-metallic elements, for example, the conductive metal may be nickel phosphorus.
  • the metal ion is typically in the form of a salt, for example copper sulphate.
  • the metal ion might instead be present in a complex such as with EDTA (ethylene diamine tetra acetic acid) or cyanide.
  • reducing agents examples include formaldehyde, glucose or most other aldehydes, or sodium hypophosphites, or glyoxylic acid or DMAB (dfmethylamineborane).
  • the substrate is preheated before the first liquid is deposited thereon. This causes the liquid to dry rapidly and spread less, achieving thinner lines.
  • a Melinex polyester substrate (Melinex is a Trade Mark) may be heated with air at 350°C for 4 seconds using a hot air gun.
  • the first liquid is deposited onto the substrate by inkjet printing.
  • the second fluid may be deposited on the first layer by inkjet printing or other techniques. Where the first liquid and/or resulting first layer are patterned, the second fluid may be deposited according to the same pattern.
  • inkjet printing processes are typically digitally controlled, different patterns can be applied using the same apparatus to different substrates. This is particularly important for the production of one-off products, customised products, or a series of uniquely identifiable products.
  • the substrate may be selected from a wide range of possibilities, including plastics, ceramics, natural materials, fabrics etc.
  • suitable substrates include plastics materials and fabrics, e.g. in the form of sheets.
  • a substrate might be a material having thereon electrical components, such as conductive, semi-conductive, resistive, capacitive, inductive, or optical materials, such as liquid crystals, light emitting polymers or the like.
  • the method of the invention need not involve significant heating and so may be used with a wide range of substrates, including heat-sensitive plastics materials.
  • the method may include the step of depositing one or more of said electrical components on the substrate, preferably by inkjet printing, prior to forming a conductive metal region on the resulting substrate.
  • the method may further include the step of depositing an electrical component onto the resulting conductive metal region, building up complex devices.
  • Said further deposition step may also be carried out using inkjet printing technology.
  • a battery may be formed on a substrate by forming two regions of different conductive metals on a substrate by the method of the invention, and electrolytically connecting the two regions by way of an electrolyte (which may be inkjet printed), thereby forming an electrochemical cell.
  • a plurality of electrochemical cells may be electrically connected in series or in parallel thereby increasing the voltage and/or current available.
  • the invention also covers a method of forming a battery by forming two regions of different conductive metals on a substrate by the method of the invention and electrolytically connecting the two regions by way of an electrolyte (which may be inkjet printed). The invention also extends to a battery formed by the said method.
  • the method can be used as one stage in the fabrication of electrical items. It is particularly appropriate for use in manufacturing electrical items which involve complex patterns, such as displays which include complex patterns of pixels.
  • Other applications include the fabrication of aerials or antenna for car radios, mobile phones, and/or satellite navigation systems; radio frequency shielding devices; edge connectors, contact and bus connectors for circuit boards; radio frequency identification tags (RFID tags); conductive tracks for printed circuit boards, including flexible printed circuit boards; smart textiles, such as those including electrical circuits; decorations; vehicle windscreen heaters; components of batteries and/or fuel cells; ceramic components; transformers and inductive power supplies, particularly in miniaturised form; security devices; printed circuit board components, such as capacitors and conductors; membrane keyboards, particularly their electrical contacts; disposable, low cost electronic items; electroluminescent disposable displays; biosensors, mechanical sensors, chemical and electrochemical sensors.
  • the method also finds application in producing an electrical connection between two components in or for a circuit.
  • the method may also be used to produce decorative features.
  • the method may include the further step of forming an additional metal layer onto a conductive metal region constituted by the second layer, e.g. by electrolytic or electroless plating or by immersion metallisation.
  • the respective liquids should fulfil the specific requirements of inkjet printing inks as regards viscosity, surface tension, conductivity, pH, filtration, particle size and ageing stability.
  • One or more humectants may be added to one or more component solutions to reduce evaporation. The particular values of these properties which are required are different for different inkjet technologies and suitable component solutions fulfilling these properties can readily be devised for a specific application by one skilled in the art.
  • the method also extends to an article prepared according to the method of the invention.
  • a liquid comprising a curable layer-forming composition for forming a first solid layer on the surface of a substrate, the liquid comprising an activator suitable for activating a second layer-forming chemical reaction, and one or more chemical components which are capable of undergoing a chemical reaction (typically responsive to a stimulus) causing the liquid to harden.
  • the invention also covers the activator liquid in combination with a second fluid.
  • the one or more chemical components comprise monomers and/or oligomers which can polymerise, forming a solid first layer.
  • the activator is preferably a catalyst.
  • the activator could comprise a chemical species which can activate the second solid layer forming chemical reaction but which is consumed or reacts in the process.
  • the activator may also comprise a reagent, or a plurality of reagents which, when brought into contact with a second liquid comprising components (preferably other components) of a second layer-forming chemical reaction, undergo a chemical reaction leading to formation of a second layer on the first solid layer.
  • Suitable solvents for the deposition of an organic acid salt of a transition metal include diacetone alcohol, mixtures of equal amounts by weight of diacetone alcohol and methoxypropanol, and mixtures of equal amounts by weight of toluene and methoxypropanol.
  • a co-solvent is preferably included to increase viscosity to suitable levels for inkjet printing.
  • the organic acid salt of a transition metal constitutes 1-3% by weight of palladium acetate, most preferably 2% by weight of the deposited liquid.
  • An equivalent concentration of another organic acid salt of a transition metal can be employed.
  • a method of forming on the surface of a substrate a first layer which is suitable for activating a second solid layer- forming chemical reaction thereon comprising the steps of: applying a curable liquid to the surface of the substrate, the curable liquid comprising an activator for a layer- forming chemical reaction; and curing the curable liquid, thereby forming a first solid layer on the surface of the substrate, capable of activating a second solid layer-forming chemical reaction.
  • the invention also extends to a method of forming a solid layer on a substrate, comprising the steps of: applying a curable liquid to the surface of the substrate, the curable liquid comprising an activator for a layer-forming chemical reaction; curing the curable liquid, thereby forming a first solid layer on the surface of the substrate, capable of activating a second solid-layer-forming chemical reaction thereon; and bringing into contact with the first solid layer a second liquid comprising components of a second solid-layer-forming chemical reaction, activated by the activator, thereby causing a second solid layer to be formed on the first solid layer.
  • UV curable catalyst formulations referred to as ALF 116 and ALF 117 were prepared according to the formulation shown in Table 1 below.
  • the monomers, oligomers and initiators used are already known from the related field of UV curable inkjet inks to have excellent curing properties and adhesion to plastic substrates.
  • These formulations contain some solvent (diacetone alcohol and methoxy propanol) acting as a carrier liquid in which the palladium acetate catalyst is soluble.
  • the solvent was allowed to evaporate off after application of the formulation to a Melinex (Melinex is a Trade Mark) polyester substrate surface by inkjet printing using an XJ500/180 print head from Xaar, UK.
  • the inks were then cured by the application of UV which began a curing procedure in which the monomer and oligomer components polymerised.
  • UV curable catalyst formulations (Figures are percentages by weight)
  • PVP K30 is a grade of polyvinyl pyrrolidinone supplied by ISP, Tadworth, UK.
  • Actilane 505 is a UV-curable reactive tetrafunctional polyester acrylate oligomer supplied by Akzo Nobel UV Resins, Manchester, UK.
  • DPHA is dipentaerythritol hexacrylate, a UV-curable hexafunctional monomer, supplied by UCB, Dragenbos, Belgium.
  • Igracure 819 and Igracure 1700 are UV photo-initiators supplied by Ciba Speciality Chemicals, Macclesfield, UK - Irgacure is a Trade Mark.
  • DPGDA is dipropylene glycol diacrylate, a UV-curable reactive diluent monomer supplied by UCB, Dragenbos, Belgium.
  • the monomers and oligomers are in liquid form.
  • Diacetone alcohol and methoxy propanol are solvents for the palladium acetate.
  • PVP constitutes a water soluble (second) chemical functionality.
  • ALF 116 cured well (with a line speed of 40 metres/minute) to give a tough scratch resistant film.
  • a copper layer forming solution consisting of Enplate 872A (30% w/w), Enplate 872B (30% w/w), Enplate 872C (10% w/w), t-butanol (5% w/w), ethylene glycol (20% w/w) and polyethylene glycol 1500 (5 % w/w) was applied to the film, no copper was deposited. We believe that this is due to the smooth, impervious surface of the cured film, which seals the catalyst into a plastic layer and prevents it from coming into contact with the copper-layer forming solution.
  • Enplate 872 A, 872B and 872C are copper plating solutions, available from Enthone-OMI of Woking, UK.
  • Enplate 872 A contains copper sulphate.
  • Enplate 872B contains a cyanide complexing agent and formaldehyde.
  • Enplate 872C contains sodium hydroxide. (Enplate is a Trade Mark.)
  • Enplate 872 A, B and C are in common use as component solutions for electroless copper plating.
  • Ethylene glycol is present as a humectant and acts to lower surface tension.
  • T-butanol is a cosolvent which reduces surface tension and increases wetting.
  • Polyethylene glycol- 1500 functions as a humectant.
  • ALF 117 includes a small amount (5 % by weight of dried film) of polyvinylpyrrolidone, which was added to the formulation with the aim that it would dissolve out of the cured layer or swell or maintain permeability upon the subsequent addition of the aqueous copper-layer forming solution, and therefore expose the catalytic sites.
  • ALF 116 this again cured very well at 40 metres/minute and this time deposited copper (at a calculated 100 nm/minute).
  • ALF 120 Three further formulations referred to as ALF 120, ALF 121, and ALF 124 were prepared as summarised in Table 2 below. Each of these is a variant of ALF 117 from Table 1.
  • ALF 120, ALF 121 and ALF 124 were applied to a Melinex polyester substrate, as described above in Example 1.
  • This copper layer was found to have good conductivity, and good adhesion to the underlying substrate. Since no copper was deposited on ALF 120 or ALF 124 this provides further evidence that the PVP material is responsible for maintaining the activity of the catalyst, and that it is likely that this occurs via the water solubility mechanism proposed above.
  • ALF 121 was then modified further to give an ink with good properties for deposition by inkjet printing.
  • ALF 125 and ALF 126b both showed good inkjet printing properties using a XaarJet 128-200 print head (available from Xaar of Cambridge, England) and both gave good quality copper deposition on a Melinex polyester substrate following the procedure described above in Examples 1 and 2. However, when making thicker copper samples of greater than 200 nm thickness, ALF125 blistered much more easily than ALF 126b.
  • ALF 126b contains higher functionality materials (Actilane 505 is tetrafunctional, DPHA is hexafunctional) and so is more highly cross-linked and therefore forms a stronger, more robust film with better adhesion to the substrate.
  • a water-swellable monomer such as HEMA (2-hydroxyethyl methacrylate), GMA (glyceryl methacrylate) or NVP (n-vinyl pyrrolidinone).
  • HEMA 2-hydroxyethyl methacrylate
  • GMA glyceryl methacrylate
  • NVP n-vinyl pyrrolidinone
  • a high boiling point water miscible solvent such as NMP (n-methyl pyrrolidinone), ethylene glycol, diefhylene glycol or glycerol could be used to keep the UV-cured layer open, and to allow penetration by the copper solution.
  • a micro-porous film structure could be prepared by the use of micro-porous particles, such as silica (inorganic) or PPVP (poly polyvinyl pyrrolidinone) particles (organic).
  • ALF 126b was then modified further to give a UV-curable catalyst ink with optimised performance, known as ALF 126f. This was used to deposit a conductive copper layer on a Melinex (Melinex is a Trade Mark) polyester substrate.
  • the composition of ALF 126f was as follows:
  • This fluid was printed with a XJ500/180 print head (available from Xaar of Cambridge, England) at 180 x 250 dpi.
  • the samples were then cured under a Fusion 500 Watt H-bulb, in 4 passes of 20 metres/min each, resulting in formation of the first layer.
  • the thickness was measured at about 500 nm.
  • the layer thickness will increase, possibly up to the theoretical maximum for this printing resolution of 2.9 microns.
  • the samples were submerged in a chemical bath containing a solution of 1.6% dimethylamineborane (DMAB) in deionised water, and processed at 40 ⁇ 2°C for 2 minutes, followed by a deionised water rinse, and drying.
  • DMAB dimethylamineborane
  • the samples were then treated with a copper layer forming solution, the solution consisting of 75% deionised water and ENPLATE Cu 872A, ENPLATE Cu 872B, and ENPLATE Cu 872C in the weight ratio 3:3:1, respectively.
  • the samples were immersed . in the copper layer forming solution under agitation for 2 minutes, while held at 45 ⁇ 2°C in a temperature controlled bath.
  • ALF 126f showed good inkjet printing properties and gave good quality copper deposition.
  • ALF 126f ink was coated onto a Melinex 339 (Dupont Teijin Films) polyester substrate using a 12 ⁇ m drawdown bar.
  • the liquid film was then exposed to UV light through apertures patterned in a 25 micron aluminium foil.
  • the UV light source was a Fusion systems F500 using an H bulb, giving a total UV dose of 0.70 J/cm 2 .
  • the exposed areas of the film cured and solidified.
  • the unexposed areas remained liquid and were easily washed away using ethanol. A further four passes under the UV lamp ensured full curing.
  • Liquid films of ALF 126f ink of between 12 microns and 24 microns were prepared on a Melinex 339 polyester substrate (Melinex is a trademark of Dupont Teijin Films) using the draw-down method.
  • the liquid films were immediately fed into an Orbotech DP100 SL Direct laser write system (Orbotech is a Trade Mark). This system uses a 4 W Paladin (Paladin is a Trade Mark) diode pumped solid state laser (Coherent Ltd) operating at 355 nm.
  • Patterns were produced using energy dosed from 20 mJ up to 100 mJ in an atmosphere of nitrogen gas (although this is not essential). The uncured areas were washed away using ethanol. The samples were then immersed in a 1.6% solution of DMAB for 2 minutes, rinsed in DI water and then plated by immersion in Enplate copper plating solution (Enplate Cu872A, Enplate Cu 872B and Enplate 872C in the weight ratio 3:3: 1, respectively) for 2 minutes at 45° C. This resulted in well adhered copper features as fine as 20 microns.

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  • Inorganic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Chemically Coating (AREA)
  • Manufacturing Of Printed Wiring (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)
  • Adhesives Or Adhesive Processes (AREA)
  • Laminated Bodies (AREA)

Abstract

L'invention concerne un procédé destiné à la formation, sur la surface d'un substrat, d'une première couche solide permettant de déclencher une réaction chimique et de former une seconde couche sur la première, le procédé consistant : à appliquer sur la surface du substrat un premier liquide comprenant une composition durcissable et un activateur permettant de déclencher la réaction chimique et de former la seconde couche ; et à durcir la composition durcissable pour former une première couche solide collée à la surface du substrat, capable de déclencher la réaction chimique et de former la seconde couche. On peut ensuite former une seconde couche sur le substrat en mettant en contact avec la première couche solide un second fluide comprenant des composants permettant de déclencher une réaction et de former une seconde couche, activé par l'activateur, pour former la seconde couche sur la première couche solide.
PCT/GB2004/005088 2003-12-05 2004-12-03 Formation de couches solides sur des substrats WO2005056875A2 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
JP2006542017A JP4881161B2 (ja) 2003-12-05 2004-12-03 基板上の固体層の形成
KR1020067013540A KR101178334B1 (ko) 2003-12-05 2004-12-03 기판 상의 고체층 형성 방법
CN200480035925.4A CN1898413B (zh) 2003-12-05 2004-12-03 基材上固体层的形成
EP04805916.6A EP1689909B1 (fr) 2003-12-05 2004-12-03 Formation de couches solides sur des substrats

Applications Claiming Priority (8)

Application Number Priority Date Filing Date Title
GB0328221A GB0328221D0 (en) 2003-12-05 2003-12-05 Formation of solid layers on substrates
GB0328221.7 2003-12-05
US52794803P 2003-12-08 2003-12-08
US60/527,948 2003-12-08
GB0401825A GB0401825D0 (en) 2003-12-05 2004-01-28 Formation of solid layers on substrates
GB0401825.5 2004-01-28
GBPCT/GB2004/004589 2004-10-29
PCT/GB2004/004589 WO2005045095A2 (fr) 2003-10-29 2004-10-29 Formation de couches sur des substrats

Publications (2)

Publication Number Publication Date
WO2005056875A2 true WO2005056875A2 (fr) 2005-06-23
WO2005056875A3 WO2005056875A3 (fr) 2005-10-20

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB2004/005088 WO2005056875A2 (fr) 2003-12-05 2004-12-03 Formation de couches solides sur des substrats

Country Status (3)

Country Link
EP (1) EP1689909B1 (fr)
KR (1) KR101178334B1 (fr)
WO (1) WO2005056875A2 (fr)

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WO2006123144A2 (fr) * 2005-05-18 2006-11-23 Conductive Inkjet Technology Limited Formation de couches sur des substrats
WO2008040936A1 (fr) * 2006-10-04 2008-04-10 Hexcel Composites Limited films en rÉsine durcissable
WO2010092392A1 (fr) 2009-02-13 2010-08-19 Conductive Inkjet Technology Limited Eléments optiques diffractifs
WO2010142976A1 (fr) 2009-06-08 2010-12-16 Conductive Inkjet Technology Limited Dispositif d'affichage
WO2012025208A1 (fr) * 2010-08-24 2012-03-01 Roche Diagnostics Gmbh Élément de test pour biocapteur et son procédé de fabrication
US8138614B2 (en) 2006-02-08 2012-03-20 Semiconductor Energy Laboratory Co., Ltd. Semiconductor device having an antenna with anisotropic conductive adhesive
WO2012140428A1 (fr) 2011-04-14 2012-10-18 Conductive Inkjet Technology Limited Améliorations apportées à et concernant des composants transparents
WO2015169495A1 (fr) * 2014-05-05 2015-11-12 Preh Gmbh Procédé de galvanisation pour des structures en îlots
WO2021111448A1 (fr) * 2019-12-03 2021-06-10 Scodix Ltd. Compositions pour former un motif sur un métal sur un substrat et leurs procédés d'utilisation

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EP0256395A2 (fr) * 1986-08-12 1988-02-24 Bayer Ag Procédé pour améliorer l'adhérence des couches de métaux déposées par voie chimique sur des surfaces en matière plastique
US5082734A (en) * 1989-12-21 1992-01-21 Monsanto Company Catalytic, water-soluble polymeric films for metal coatings
WO1992021790A1 (fr) * 1991-06-07 1992-12-10 Monsanto Company Fabrication d'articles metalliques a partir d'images imprimees
US5510139A (en) * 1992-01-16 1996-04-23 Ameg Additive Metallisierung-Entwicklunge-Und Anwendungssesellshaft Gmbh Process for assembly and bonding of electronic components on an insulating support
US5411795A (en) * 1992-10-14 1995-05-02 Monsanto Company Electroless deposition of metal employing thermally stable carrier polymers
EP0696515A1 (fr) * 1994-07-11 1996-02-14 Agfa-Gevaert N.V. Procédé d'impression par jet d'encre
US5989653A (en) * 1997-12-08 1999-11-23 Sandia Corporation Process for metallization of a substrate by irradiative curing of a catalyst applied thereto
WO2002059209A1 (fr) * 2001-01-24 2002-08-01 Toray Engineering Company,Limited Solution de precurseur de resines polyimides, lamines pour composants electroniques fabriques a l'aide desdites solutions, et procede de production desdits lamines

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Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8642117B2 (en) 2005-05-18 2014-02-04 Conductive Inkjet Technology Limited Formation of layers on substrates
WO2006123144A3 (fr) * 2005-05-18 2007-03-08 Conductive Inkjet Tech Ltd Formation de couches sur des substrats
WO2006123144A2 (fr) * 2005-05-18 2006-11-23 Conductive Inkjet Technology Limited Formation de couches sur des substrats
US8138614B2 (en) 2006-02-08 2012-03-20 Semiconductor Energy Laboratory Co., Ltd. Semiconductor device having an antenna with anisotropic conductive adhesive
WO2008040936A1 (fr) * 2006-10-04 2008-04-10 Hexcel Composites Limited films en rÉsine durcissable
EP1980647A1 (fr) 2006-10-04 2008-10-15 Hexcel Composites Limited Revêtement résinieux durcissable
US8313825B2 (en) 2006-10-04 2012-11-20 Hexcel Composites Limited Curable resin films
WO2010092392A1 (fr) 2009-02-13 2010-08-19 Conductive Inkjet Technology Limited Eléments optiques diffractifs
US8922892B2 (en) 2009-02-13 2014-12-30 Conductive Inkjet Technology Limited Method of producing a diffractive optic element and the resulting element
WO2010142976A1 (fr) 2009-06-08 2010-12-16 Conductive Inkjet Technology Limited Dispositif d'affichage
US8793865B2 (en) 2010-08-24 2014-08-05 Roche Diagnostics Operations, Inc. Biosensor test member and method for making the same
US8468680B2 (en) 2010-08-24 2013-06-25 Roche Diagnostics Operations, Inc. Biosensor test member and method for making the same
WO2012025208A1 (fr) * 2010-08-24 2012-03-01 Roche Diagnostics Gmbh Élément de test pour biocapteur et son procédé de fabrication
US8920728B2 (en) 2010-08-24 2014-12-30 Roche Diagnostics Operations, Inc. Biosensor test member and method for making the same
WO2012140428A1 (fr) 2011-04-14 2012-10-18 Conductive Inkjet Technology Limited Améliorations apportées à et concernant des composants transparents
US8980531B2 (en) 2011-04-14 2015-03-17 Conductive Inkjet Technology Limited Transparent components
WO2015169495A1 (fr) * 2014-05-05 2015-11-12 Preh Gmbh Procédé de galvanisation pour des structures en îlots
WO2021111448A1 (fr) * 2019-12-03 2021-06-10 Scodix Ltd. Compositions pour former un motif sur un métal sur un substrat et leurs procédés d'utilisation
US11346000B2 (en) 2019-12-03 2022-05-31 Scodix Ltd. Method for patterning a metal on a substrate and articles comprising same

Also Published As

Publication number Publication date
KR20060129247A (ko) 2006-12-15
EP1689909B1 (fr) 2017-10-11
KR101178334B1 (ko) 2012-08-29
EP1689909A2 (fr) 2006-08-16
WO2005056875A3 (fr) 2005-10-20

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