WO2004017688A1

WO2004017688A1 - Depositing solid materials

Info

Publication number: WO2004017688A1
Application number: PCT/GB2003/003375
Authority: WO
Inventors: Daniel Robert Johnson; William Norman Damerell
Original assignee: Qinetiq Limited
Priority date: 2002-08-16
Filing date: 2003-08-04
Publication date: 2004-02-26
Also published as: GB0219091D0; GB2391871A; AU2003252969A1

Abstract

To produce an electrical component, a conductive area is formed, covered with a thin non-conductive layer, and further covered with a conductive layer. This will form a capacitor or cell as part of the PCB or other substrate itself. Oxide coatings, capacitors and multifunctional multilayer composite structures can be formed in this way. Cells can be formed by suitable galvanic or electrochemical layered structures. The present invention therefore provides a deposition apparatus, a method of depositing a component, and the component itself. The deposition apparatus includes an inkjet printhead (1) to deposit a fluid (2) containing at least one reagent capable of reaction to produce a conductive deposit (5) on the substrate (3). Where the substrate is porous, an electrochemical cell or capacitor can be constructed using electrodes on either side of a porous substrate in, which is provided the electrolyte, or dielectric. Fuel cells can also be provided by appropriate design of the structure. The device can be encapsulated, for example by depositing a two-phase adhesive over at least the active area.

Description

DEPOSITING SOLID MATERIALS

The present invention relates to the deposition of solid materials. It provides a method of doing so, and a printer for doing so.

The production of printed circuit boards (PCBs) is a major market that has expanded with the rise in electronic, computing and other such industries. As the process of electronic integration has developed, there has been a corresponding demand for finer and more accurate detail in the PCB production process, with narrower conductive tracks and greater densities of components. Finer tracks ease the use of surface mount technologies such as 'flip chip' or the like.

Electroless deposition is used to coat whole surfaces, and the formation of metal patterns requires additional and costly processing such as photolithography and etching. Existing PCB technology uses lithographic techniques to obtain a resolution of 50 m, but this is an optimal outcome that is not typically available over the whole of a large PCB. The process is also limited by inherent flaws such as errors arising from faulty or damaged lithographs, scatter of light, and possible undercutting of metal tracks during etching.

The present invention seeks to provide a 'solid' printer which can deposit electrical components, and/or a process for doing so. This needs to be able to deposit an essentially solid material and/or a material which can subsequently interact and/or change its properties, for example to produce another material that may solidify or change its physical state.

Our previous application no: GB0113408.9 filed on 4 June 2001 proposed the use of an inkjet printer to apply a promoter type material such as SnCl₂ or catalytic palladium to a substrate prior to exposing the substrate to an electroless deposition process. Such processes employ a solution of a metal salt and a reducing agent in combination with stabilisers to prevent plating out of the metal until exposure to the promoter. This allows PCBs to be made to the resolution of an inkjet printer, which is now down to the order of 20 μm.

However, this approach still requires the use of an electroless deposition solution. The stabilisers employed in such electroless deposition solutions can be aggressive in nature and it may be desirable to avoid these. However, a stabiliser is normally needed since these solutions are unstable without them and so can spontaneously plate out at random.

Another method uses finely divide or even nanometric size particles of conductive metals or similar. This too has many problems, one being the cost of such finely divided materials. Another is keeping the particles from settling and/or clogging of any picolitre dosing device such as used in ink jet or bubble jet methods. Also particles of metal making occasional physical contact are inferior as a conductor as compared to continuous metal. Furthermore, while this conductivity can be improved by heating, the temperatures required (~300°C) are too high for most substrates, and the extra process adds cost and complexity.

One objective of the present invention is to deposit material directly onto the substrate by using a fluid applicator such as an inkjet printer to apply at least two fluids which react to yield the material whose deposition is required, particularly where a conductive metal is needed.

To produce one example of an electrical component, a conductive area is formed, covered with a thin non-conductive layer, and further covered with a conductive layer. This will form a capacitor as part of the PCB or other substrate itself. Other single or multi-component devices such as oxide coatings, capacitors and multifunctional multilayer composite structures can be formed in this way. Cells can be formed by suitable galvanic or electrochemical layered structures.

A significant advantage of the present invention comes from the ability to meter exact quantities through the printing process, thereby achieving a high level of control over the type of materials fabricated and the yield and cost of production processes. For example, exact quantities of expensive materials may be deposited, layers may be built to precise thicknesses and materials of known stoichiometry and density may be prepared.

The present invention therefore provides a deposition apparatus, comprising a printhead adapted to deposit fluid agents on a substrate, reservoirs associated with the printhead containing reagents for deposition on the substrate, including at least one reagent capable of reaction on the surface to produce a conductive deposit.

The components to be deposited can be batteries or cells, such as electrochemical, bimetallic or other galvanic cells. Where the substrate is porous, an electrochemical cell can be constructed using electrodes on either side of a porous substrate in which is provided the electrolyte.

Capacitors can be provided by means of a parallel plate with a deposited dielectric between the plates, or by way of a parallel plate with the substrate forming the insulating layer. Where the substrate is porous it can again be treated to provide a dielectric layer.

Fuel cells can also be provided by appropriate design of the structure.

Conductors can be electronic or ionic in nature. The reagent is preferably non- conductive prior to reaction. A wide variety of reactions are suitable, including catalytic and auto-catalytic deposition.

The device can be encapsulated, for example by depositing a two-phase adhesive over at least the active area. A pair of electrodes can be deposited in an interlacing arrangement such as a pair of interlocking comb-shapes. This will maximise the length over which they are adjacent. An electrolyte between such electrodes will therefore experience a large surface area but with minimal use of space.

The component can include plated layers, which can be deposited in place as described herein or which can be electrochemically plated in a selective fashion onto areas of the substrate which have been pre-treated using a deposition apparatus.

It is preferred that all of the layers of the electrical component are formed by the deposition method set out herein, but significant advantages can still be obtained if only selected layers are deposited by this method.

This route offers significant advantages in particular, it is a low temperature process capable of operating below 300°C and preferably below 100°C, and it operates via a non-contact process.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying figures, in which;

Figure 1 shows a typical battery electrode fabrication methodology using inkjet printing.

Figure 2 shows how the formed electrodes are combined to form a battery or capacitor.

Figure 3 shows how the properties of an electrode such as adhesion and surface area can be enhanced by the porosity of the substrate material.

This invention describes the principle of using inkjet printing to deposit materials fabricated into electrodes for electrochemical power sources or the "battery" as herein defined. Additionally, methods are described for the formation of other electrical storage devices such as capacitors, for example, super capacitors. Accordingly, the objective of the present invention is to use print transfer mechanisms to deposit patterns and textures of materials that may be fabricated into electrodes for use in the "battery" and "capacitor".

The battery is a device that enables energy liberated from a chemical reaction to be converted directly into electricity. It is invariably a portable source of power and in many circumstances may be needed to store electrical energy from an external source for later use. The battery comprises two electrodes, one the anode and the other the cathode, both of which have a metal electrical collector and an "active material" herein defined as materials that enter into the electrochemical reaction. The metal collector itself can be an active material as in the case of for example the lithium battery or lead/acid battery. Otherwise, the collector metal may conveniently contain additional active material for example an oxide coating or a stored gas. Many cell types exist based upon dissimilar anode and cathode materials which form a redox couple.

The electrochemical reaction between the electrodes may be irreversible (primary cells) or reversible (secondary or rechargeable cells). In addition to these are a new generation of fuel cells that employ electrodes to synthesise, store and/or convert hydrogen or organic molecules directly into electrical power.

Typical examples of manufacturing methods and cell types are covered in the literature (Modern Batteries: An Introduction to electrochemical power sources CA. Vincent, F. Bonion, M Lazzari, B. Scrosati, Publ Edward Arnold London 1984).

Batteries are useful for a wide range of applications from vehicle propulsion, energy load levelling of utility electricity, and backup supplies to equipment from computers to memory chips.

If the battery substrate is a thin sheet of material, e.g. a polymer or synthetic inkjet paper, then the power source may be integrated into a powered device on the same sheet, or may equally be easily laminated to the sheet. Examples include electronic paper, visual displays such as liquid crystal displays and proprietary systems such as Zenithal Bistable Display (ZBD), or light emitting materials such as electrolumiscents and other light emitting polymers. The devices may also be used to power "active" radio frequency emitters and readers such as those employed in security tagging, anticounterfeiting and other fields e.g. hygiene, food safety etc. The battery may be thus disposable (primary type) or rechargeable allowing the device it powers to be reactivated and not wasted. The re-charger may also include other remote power sources such as thin film solar cells, integrated into the structure.

In a similar field, electrodes that are separated by a dielectric layer form the basis of the capacitor. The surface area of the electrodes essentially governs the capacity of these as storage devices and with super capacitors the electrodes are designed to exploit this fact.

Using the methods herein it will be possible to design and manufacture electrodes that can be configured to a wide range of current and voltage specifications and therefore to provide a wide range of power densities from either the battery or capacitor applications. The electrodes described herein will also have their properties affected using the inkjet printing method, for example materials may be incorporated into the printed layer such as particle fillers and material binders, to improve robustness and/or increase the surface area of active materials. Where catalysts are needed to promote reactions in a battery, the inkjet is also proposed as the most cost-effective way or providing such surfaces onto and into electrode materials. It is also proposed that the final device can be substantially fabricated using inkjet printing, for example by deposition of electrolyte materials, as liquids, or formed from liquids into gels and solids.

Equally the whole device can then be encapsulated using adhesives and sealant printed by said method.

It is also proposed that the properties of the printed substrate will be exploited to achieve desired effects in the final device, such as porous materials to change the surface area of electrodes and to act as electrode separators. The advantage of the present invention is that inkjet printing is a novel prototyping and manufacturing process for the fabrication of the battery and capacitor. The utilisation of materials and low waste make the process cost- effective and easy to integrated into CAD/CAM.

In the present invention, a number of electrodes may be fabricated on a range of substrates to produce designs of batteries and capacitors suitable for a particular application. The electrodes can operate as charge collection materials for electrical connection and termination and include active materials as defined above.

In the first embodiment metal electrodes are fabricated by first inkjet printing patterns of inks that are able to sponsor electroless metal deposition. The inks may contain fine dispersions of catalytic or autocatalytic metals, or alternatively these may be formed by inkjet printing precursor reagents from separate devices such that they react near or on the substrate to produce the same. The resulting pattern of printed material is thus able to sponsor electroless deposition of the same metal (autocatalytic) or a range of less noble metals (catalytic). The metals can then form the basis of battery electrodes. These may be used directly as electrodes of differing electroless metals to form a redox couple i.e. galvanic cell in an electrolyte. Alternatively, after the electroless process, active battery materials may be formed on these layers as oxides or chalcogenides, by chemical reaction or alternatively, inkjet coated with the same active materials. The electroless metal electrode may also be electroplated with another metal to of a higher redox potential than itself to generate other electrode configurations. As a further alternative, the electroless metal can be deposited using a platinum series catalyst to sponsor deposition e.g. Pt or Pd materials by inkjet printing. Where necessary, the electroless metal deposit can once more be inkjet printed with the same or different platinum series catalysts onto and into it, the resulting surface-catalysed metal, e.g. Platinum or Nickel can then be fabricated into an electrode used in a hydrogen or hydrocarbon fuel cell where the catalyst material is able to sponsor chemical reaction.

In the second embodiment, metal ion-containing materials can be inkjet printed either as electrode materials themselves, for example lithium intercalated graphitic carbon particles, or as intercalated oxide materials which maybe also be deposited onto metal layers, formed using the aforementioned electroless methods, and acting as electrical connections.

In the third embodiment, textural effects are exploited in the aforementioned inkjet methods. In this instance it is possible to increase the functionality of the ink and substrate to improve properties such as adhesion, electrode surface area, electrode separation, electrolyte incorporation and dielectric effects. For example, the surface area of a porous substrate material e.g. ceramics, gels, membranes, foams, fabrics or porous synthetic inkjet paper, may increase electrode surface area, improve electrode binding and contain electrolyte within its pores. In addition to or alternatively, the same effects may also be achieved using binders and fillers in the inkjet printing inks used to deposit materials into patterns herein before described.

In the fourth embodiment, the inks described in this patent can be formulated to change their penetration depth into porous substrates and hence the materials contained within them, by changing the drying rate through temperature processes or through the choice of solvent employed in the ink.

In the fifth and final embodiment it is proposed that other battery components and fabrication processes may be carried out using inkjet printing. For example, an ink may comprise materials used to form the electrolyte in the battery. The ink may be printed and kept in the liquid phase, lose a volatile component to become a gel or lose all solvent to become a solid. Other materials that maybe be inkjet printed include porous electrode separator layers and encapsulating and adhesive layers.

The following examples of batteries by inkjet include the Copper/Nickel battery, Nickel/Iron battery, the fuel cell and the lithium ion battery. To one skilled in the art, it should be possible to transfer these ideas to other battery types.

The examples first describe a method of forming metal electrodes that are needed either for electrical charge collectors in a battery containing active ingredients or are themselves the sources of these materials. The process described to form metal electrodes is based upon the principles of electroless deposition. Examples of these are nickel, cobalt, copper and tin.

The substrate that will house the electrodes first needs to be treated with a deposition promoting material herein described. In the present invention said material is either formulated directly into an ink or formed by co-deposition and subsequent reaction of two co-incident inks. One may deposit the inks from a single or greater number of print transfer mechanisms, for example an inkjet printing system.

In the present invention a deposition promoting material may be formed as a printed pattern by using one of the following three ink formulations:

Formulation 1 comprises a single ink that contains deposition promoting material which is catalytic to electroless metal deposition. It contains:

a: A reduced complex of palladium or platinum series metal made from mixing together solutions of the dissolved metal compound and a tin(ll) compound.

b: A solvent or mixture of solvents.

c: Binders and fillers, if necessary, to change the chemical, mechanical and physical properties of the ink and the printed layer.

Formulation 2 comprises two inks that are co-deposited and co-incident on the printing surface that react to form deposition-promoting material which is catalytic to electroless metal deposition. Ink 1 comprises the following:

1. A palladium compound.

2. A solvent or mixture of solvents.

3. Binders and fillers, if necessary, to change the chemical, mechanical and physical properties of the ink and the printed layer. Ink 1 differs from ink 2 in that the palladium compound is replaced by a tin (II) compound.

Formulation 3, comprises two inks, that are co-deposited and co-incident on the printing surface that react to form a deposition promoting material that is autocatalytic to electroless metal deposition. In this example Ink 1 contains a metal which in the present example comprises.

1. A copper (II) compound.

2. A solvent or mixture of solvents.

3. Binders and fillers, if necessary, to change the chemical, mechanical and physical properties of the ink and the printed layer.

Ink 2 differs from ink 1 in that the copper compound is replaced by a reducing agent, for example dimethylamineborane, DMAB. The dispersion of copper metal that is formed by reacting the two inks is thus autocatalytic to electroless copper deposition.

The printed and dried patterned ink layer containing one of the aforementioned deposition promoting materials is then placed in an appropriate electroless metal bath solution and the desired metal plated only onto the printed area.

The following represent examples of how these metals and the inkjet printer may be used to fabricate a range of batteries and other charge storage devices:

Example 1. The Copper-Nickel battery

Using a printed ink containing either a catalytic or autocatalytic material hereinbefore described it is possible to deposit electroless copper to form a number of electrodes and electroless Nickel to form others. The simplest electrochemical battery is one comprising electrodes of dissimilar metals. Therefore by placing copper and nickel electrodes into an electrolyte it is possible to produce one or more galvanic cells that become a battery with sufficient voltage and capacity that may be used to power devices.

Example 2. The Nickel-Iron battery

The Nickel/Iron battery requires two electrodes to be formed, one of Ni with a coating of Ni(O) OH and the other electrode of Iron, electroplated onto a current collector, again Nickel.

A pattern of the hereinbefore described ink and its subsequent electroless coating of nickel is performed. One of the nickel electrodes was placed as the anode in an aqueous solution of potassium hydroxide and any electrical conductor, for example, in this case Ti0₂ electrode coating Ti sheet (Ebonex), was the cathode. The nickel is anodised in the range 0.2 to 1 volt with respect to a Ag/AgCI reference electrode. A second nickel electrode is placed as the cathode in a solution of iron (II) sulphate in the concentration range 0.1 to 1 molar and any conductor is used as the anode, e.g. Ebonex. Iron is electroplated onto the nickel. The two pieces of anodised and Iron plated nickel electrodes are then immersed into a potassium hydroxide solution and a rechargeable Nickel-Iron cell results, which can thus be made into a battery of cells to power electronic devices and store electrical charge from an outside source.

As a further improvement it is possible to coat nickel onto both sides of a porous synthetic inkjet paper and fabricate one side as an anode and the other as a cathode. Therefore the substrate will act at the electrode separator and electrolyte- containing medium once potassium hydroxide solution is absorbed from soaking the electrodes and substrate into a KOH solution.

Example 3. The Fuel Cell

In the fuel cell, a metal "collector" electrode is used in combination with a platinum group catalyst to activate the battery reaction. The surface area of these electrodes and utilisation of the catalyst are key factors in the rate of reaction, and hence the current density of the fuel cell. The present example uses a porous substrate material, such as a microporous membrane filter, ceramic sheet or porous synthetic inkjet paper, onto and into which the ink hereinbefore described is printed into a user-defined pattern. The ink in the present example is chosen to contain a platinum group metal catalyst that will not only sponsor electroless deposition of a chosen metal but also act as the catalyst used to sponsor reaction on the resulting fuel cell electrodes. After printing of the catalyst and electroless deposition of, for example nickel, the electrode is suitable as an electrode in said fuel cell, for example, a polymer or solid oxide, hydrogen fuel cell. A substrate material being porous increases the surface area of the deposited electroless metal electrodes by virtue of its high surface area. The porosity of the substrate also enables the initial catalyst layer, used to sponsor the electroless metal deposition, to remain exposed and be useful in the resulting fuel cell to catalyse reaction. However, it may be preferable to print more of the catalyst containing ink onto and into the final electroless metal electrode, so that all surfaces become active in the fuel cell reaction. The user-defined pattern described in this example can be made to comprise a high density of continuous features that are sufficiently small to increase the surface area of the final metal electrode yet more. Very fine patterns of nickel having a 16μm nickel features could be achieved using inkjet printing to pattern the substrate with the deposition promoting material. The ink could be formulated to change the penetration depth of the sponsoring material. The porous substrate may be employed in the final fuel cell as a separator of electrodes perhaps on separate sides of the substrate and also to contain electrolyte materials where appropriate.

Example 4. The Capacitor and Super Capacitor

The capacitor is an electrical charge storage device with a capacity solely dependent upon the surface area of its electrodes. In the present example, methods are employed to maximise this surface area.

The ink hereinbefore described is printed onto and absorbed into a porous substrate, to form a user-defied pattern with small feature sizes. Electroless nickel is coated onto the pattern to produce an electrode. The fine continuous pattern of metal combined with its high surface area electrode is suited to capacitor application. Very fine patterns of nickel having nickel features of the order of 20μm could be achieved using inkjet printing to pattern the substrate with the deposition promoting material. The ink could be formulated to change the penetration depth of the Nickel layer. In addition, the porous substrate may also be employed as the dielectric layer separating two such electrodes deposited onto opposing sides of the substrate.

Example 5. The Lithium ion battery

A number of lithium ion-containing electrodes are formed by permanent (primary battery) or reversible electrode reactions of lithium with associated cathode materials. In primary cells cathode materials include thionyl chloride, copper oxide, manganese oxide, and poly(carbon monofluoride) whereas secondary or rechargeable cathodes include transition metal oxides and chalcogenides, for example vanadium oxides, cobalt oxide and variants of this with nickel and titanium disulphide. The rechargeable batteries reversible intercalation of lithium ions provided from the counter electrode (anodes) either as a foil of the metal or more preferably one containing lithium intercalated ions in, say carbon.

It is therefore possible to inkjet a lithium ion containing carbon electrode formulated into ink. The lithium ion containing carbon electrode can thus be printed into a user-defined pattern onto and into a suitable substrate material. The substrate can for example be porous to increase the surface area of the electrode and to allow greater adhesion of the electrode. Once the ink has dried out the electrode is thus the anode of a lithium battery. Equally this material may be printed onto a metal coated substrate hereinbefore described.

In the present example the cathode material is prepared by printing an ink containing an autocatalytic or catalytic material, hereinbefore described, into a user defined pattern on a substrate material, so that an electroless metal of cobalt and cobalt-nickel are deposited onto said substrate. The substrate may comprise a porous material onto and into which the ink and thereafter electroless metal or metals are deposited. The resulting metal pattern has then its surface substantially oxidised using a suitable reagent or oxidising ambient. The resulting electrodes thus contain metal or metals as electrodes with an active oxide coating for use in the lithium ion battery. By placing the lithium ion-carbon electrode and oxidised metal electrode in a suitable electrolyte containing lithium ions it is possible to construct a lithium ion cell and battery using such electrode, which may power electrical devices and store electrical charge for an external source.

The substrate may indeed be used as a separator and contain electrolyte and opposing sides of the substrate may have the anode and cathode materials fabricated onto them by said processes.

Turning to Figure 1 , a metal electrode is fabricated into' a user-defined pattern using a catalytic or autocatalytic ink deposited from one or more inkjet heads 1. The printed and dried pattern 2 on substrate 3, which may be porous or non-porous, is placed into an electroless bath solution 4 and a chosen metal deposited onto and into the pattern 5 and not its surrounding area. At this point it may be possible to use the metal as a battery electrode or subject it to other processes to achieve a suitable electrode. For example, one or more inkjet heads 6 may print an active battery material, such as a metal ion containing material and/or catalyst onto the metal pattern 5, or alternatively this material may be printed into a pattern without the metal backing layer provided it has suitable electrical conductivity as a battery terminal. As a further alternative, the metal backing layer may also have been formed by another metal deposition process 7 and the inkjet then employed to deposit the active battery material.

The electroless metal 5 may itself by changed chemically for example oxidised in solution 7 or another suitable medium to produce a battery material 8 on the pattern. Instead, the metal pattern 5 can become the cathode 10 of an electroplating solution 11 , where another material such as a metal can be plated onto it to form another battery electrode on the pattern 5. Now turning to figure 2, electrodes made by one or more of the processes in figure 1 are combined as the anode 13 and cathode 14 in an electrolyte 15, to produce a battery power source or capacitor.

Turning to figure 3, it is possible to put a battery or capacitor electrode material 16 onto and into a porous substrate material 17 and produce a textured electrode surface that may enhance the properties of the electrode by virtue of its greater effective surface area.

Claims

1. A deposition apparatus, comprising a printhead adapted to deposit fluid agents on a substrate, reservoirs associated with the printhead containing reagents for deposition on the substrate, including at least one reagent capable of reaction on the surface to produce a conductive deposit.

2. A deposition apparatus according to claim 1 in which the conductive deposits are electrically conductive.

3. A deposition apparatus according to claim 1 in which the conductive deposits are ionically conductive.

4. A deposition apparatus according to any one of the preceding claims in which the reagent is non-conductive prior to reaction.

5. A deposition apparatus according to any one of the preceding claims in which the reaction is a catalytic deposition.

6. A method of making an electrical component including conductive regions comprising the steps of depositing from a printhead a variety of fluid reagents onto a substrate, the different reagents being deposited in layers thereby to build the electrical component on the substrate.

7. A method according to claim 6 in which the conductive regions are electrically conductive.

8. A method according to claim 6 in which the conductive regions are ionically conductive.

9. A method according to any one of claims 6 to 8 in which the reagent is non- conductive prior to reaction.

10. A method according to any one of claims 6 to 8 in which the reaction is a catalytic deposition.

11. A method according to claim 6 in which the component is a cell or battery.

12. A method according to claim 11 in which the component is one of a bimetallic and a galvanic cell.

13. A method according to claim 11 in which the component is an electrochemical cell.

14. A method according to any one of claims 11 to 13 in which the substrate is porous and the cell is constructed using electrodes on either side of the substrate, in which is provided the electrolyte.

15. A method according to claim 6 in which the component is a capacitor.

16. A method according to claim 13 in which the capacitor comprises a pair of parallel plates with a deposited dielectric between the plates, or by way of a parallel plate with the substrate forming the insulating layer.

17. A method according to claim 16 in which the substrate is porous and the capacitor is constructed using electrodes on either side of the substrate.

18. A method according to claim 17 in which the substrate is treated to provide a dielectric.

19. A method according to claim 6 in which the component is a fuel cell.

20. A method according to any one of claims 6 to 19 which is conducted at less than 300°C.

21. A method according to any one of claims 6 to 19 which is conducted at less than 100°C.

22. A method according to any one of claims 6 to 19 in which the device is encapsulated.

23. A method according to claim 22 in which encapsulation is via the deposition of a two-phase adhesive over at least the active area.

24. A method according to anyone of claims 6 to 23 in which conductive regions are deposited in an interlacing pattern thereby to increase the adjacent length.

25. A method according to any one of claims 6 to 23 in which the component includes layers electrically plated in a selective fashion onto areas of the substrate which have been pre-treated by the reagent.

26. A method according to any one of claims 6 to 25 employing an inkjet printer.

27. An electrical component comprising a plurality of layers deposited in place by the apparatus of any one of claims 1 to 5 or according to the method of any one of claims 6 to 26.

28. A deposition apparatus substantially as described herein with reference to and/or as illustrated in the accompanying figures.

29. A method of depositing a component substantially as described herein with reference to and/or as illustrated in the accompanying figures.

30. An electrical component substantially as described herein with reference to and/or as illustrated in the accompanying figures.