Inkjet printed circuit board

Abstract

To provide novel method and material for precisely patterning conductive coatings in the field of inkjet printed circuit boards.SOLUTION: According to an embodiment described herein, there is provided a method that includes depositing a conductive material on a substrate, applying a primer material that is soluble in water or an aqueous acid to the conductive material, inkjet printing an acid-resistant pattern material that is reactive with the primer material onto the primer material in a pattern to form an acid-resistant mask, and exposing the substrate to an acid to etch the exposed portions of the conductive material.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD OF THE INVENTION The embodiments described herein relate generally to the manufacture of circuit boards using inkjet printing processes. This application describes novel methods and inks for inkjet printed circuit boards. [Background technology]

[0002] Printed circuit boards (PCBs) are typically made by forming a conductive sheet, for example made of copper, on a non-conductive substrate, masking portions of the conductive sheet, and etching the unmasked portions to form a pattern of conductive traces on the non-conductive substrate. The masking is typically done with an acid-resistant resin material. The copper is typically etched using an acid solution. The mask material protects the copper underneath from being etched by the acid. A commonly used process involves printing the mask material onto the conductive sheet using an inkjet printing process. Printed circuit board products can include a single board with circuits printed on one or both sides, or multiple boards with multiple circuits stacked together to form a complex device.

[0003] In the inkjet process for forming a negative image of a circuit pattern on a printed circuit board device, a primer material is coated onto the substrate, and then a material reactive with the primer is applied onto the substrate in a patterned manner via inkjet printing. This reactive material reacts with the primer, thereby fixing it in place. The primer is typically a polycation-based material such as polyethyleneimine, a divalent salt matrix, or a vinylpyrrolidone polymer. The pattern material is an acid-resistant material reactive with the polycation-based material. Examples of such materials include acrylic resins and styrene-acrylic resins. The primer is typically coated onto a metal surface and allowed to dry. The pattern material is then applied in a patterned manner, reacting with the primer and fixing it in place. The pattern material is typically applied in a basic state (above pH 7.0) to react with the primer. Acids such as HCl can also be added to the primer to accelerate the reaction.

[0004] The base contained in the patterning material is often volatile. For example, ammonia is sometimes used. When the base contained in the patterning material is volatile, it becomes difficult to use it as an inkjet material. This is because the composition and properties of the inkjet material change when the volatile material is exposed to the outside air, making the material application by inkjet printing unstable. The viscosity of the material changes, leading to inaccurate application of the material to the substrate. As a result, the patterns formed in the conductive material often deviate from the tolerances. In the field of inkjet printed circuit boards, new methods and materials are needed for accurately patterning conductive coatings. Summary of the Invention

[0005] According to embodiments described herein, a method is provided that includes depositing a conductive material on a substrate; applying a primer material that is soluble in water or an aqueous acid solution to the conductive material; inkjet printing an acid-resistant pattern material that is reactive with the primer material onto the primer material in a pattern to form an acid-resistant mask; and exposing the substrate to acid to etch the exposed portions of the conductive material.

[0006] According to other embodiments described herein, there is provided a method including depositing a conductive material on a substrate; inkjet printing an acid-soluble primer material comprising a polycation-based material over all areas of the conductive material; inkjet printing an acid-resistant pattern material comprising a polyanion-based material in a patterned manner onto the primer material to form an acid-resistant mask; and exposing the substrate to acid to patternedly remove portions of the conductive material.

[0007] According to other embodiments described herein, there is provided a method including depositing a conductive material on a substrate; inkjet printing an acid-soluble primer material comprising a polycation-based material and a solvent over all areas of the conductive material; removing the solvent to solidify the primer material; patternwise inkjet printing an acid-resistant pattern material comprising a polyanion-based material onto the solidified primer material to form an acid-resistant mask; and exposing the substrate to acid to patternwise remove portions of the conductive material. [Brief explanation of the drawings]

[0008] In order that the foregoing features of the present disclosure may be understood in detail, the present disclosure as summarized above will now be more particularly described by reference to embodiments, some of which are illustrated in the accompanying drawings. It will be understood, however, that the accompanying drawings depict only exemplary embodiments and are therefore not intended to limit the scope thereof, as other equally effective embodiments are possible.

[0009] [Figure 1]1 is a flowchart outlining a method according to one embodiment.

[0010] [Figure 2] 4 is a flowchart outlining a method according to another embodiment;

[0011] To facilitate understanding, elements that are common between the figures will be designated by the same reference numerals whenever possible. Elements and features of one embodiment may be conveniently incorporated into other embodiments without further description. DETAILED DESCRIPTION OF THE INVENTION

[0012] The process for manufacturing a printed circuit board described herein uses an inkjet process to apply a mask material to a substrate in a pattern. The mask material is a two-component material formed from stable precursors, at least one of which is printed into the pattern using the inkjet process. The two-component material is a stable, acid-resistant material that defines a circuit pattern to be resolved into a conductive coating on the printed circuit board.

[0013] FIG. 1 is a flowchart outlining a method 100 according to one embodiment. At 102, a primer is formed on a conductive material layer of a substrate. The substrate can be any material that will support a conductive material layer. For example, the substrate can be a conventional blank circuit board made of resin, optionally impregnated with polymer fibers. The substrate can also be glass, a polymer film, or other material on which a circuit or microcircuit is formed. The conductive material layer is typically a metal or any material that is both conductive and acid-soluble. Copper is often used as an example.

[0014] Primers are ionic materials that can be applied as a liquid and solidified into a layer. The primer material can be a polymer precursor or a polymeric material dissolved in a solvent. Primer polymers are typically polycationic (i.e., polybasic) polymers that can accept one or more protons to become cationic. Polycationic polymers have multiple configurations that can accept protons from proton donors to form ionic bonds or catalyze the formation of covalent or quasi-covalent bonds. Examples of polymeric materials that can be used for the primer material include polyethyleneimine, polyspermine, polyspermidine, polyputrescine (polybutanediamine), and other related polyamine polymers (which can be substantially linear or crosslinked), polyamidoamine, polyvinylpyrrolidone, polydiallyldimethylammonium chloride, polylysine, polytriazine, polyaminal, and polythioaminal, as well as natural and semi-synthetic polycationic materials such as chitosan, gelatin, cellulose, and starch derivatives such as dextran and dextrin, pectin, polypeptides, and alginic acid. These materials can be used as homopolymers, copolymers, or multipolymers, and may be copolymerized, crosslinked, or dendrimerized with other monomers or polymers, such as vinyl species (i.e., polyaminodiacrylate coesters), epoxy species, or urethane species. To the extent that polymerizable materials, such as vinyl species or epoxy species, are included in the primer precursor, activators, such as radical activators and co-activators (e.g., copolymerizable monomers, such as epoxy and urethane types), may also be included. Polymeric primer materials are typically acid-soluble, and any primer material that does not react with the pattern material can be subsequently removed to expose the conductive material so that it can be etched.

[0015] The polymeric primer material is applied to the conductive material of the substrate using an aqueous precursor containing the polymeric primer material. The aqueous precursor is applied as the first component of a two-component system that fixes the acid-resistant mask pattern on the conductive material. Typical liquid vehicles for applying the primer material include mixtures of water and organic, water-miscible cosolvents, such as monoethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, glycerin, aliphatic and aromatic amides, carboxylic acids, ethers, esters, alcohols, organic sulfides, organic sulfoxides, sulfones such as sulfolane, carbitol, butyl carbitol, cellosolve, aminoalcohols (i.e., aminomethylpropanol), ketones, N-methylpyrrolidone, cyclohexylpyrrolidone, hydroxyethers, lactones, imidazoles, and mixtures thereof. The non-aqueous component typically comprises from 0% to about 50% by weight and serves to dissolve other additives that may be used, such as colorants (i.e., Bayscript blue dye), salts, chelating agents (i.e., Trilon B), etc. Wetting agents such as BYK-345, BYK-307, BYK-306, BYK-308, BYK-333, BYK-341 available from BYK Chemie, Fluorad FC-120 or other fluorosurfactants, Masurf FS-1620 available from Mason Chemical Company, Surfinol 104PG and Dynol 604 available from Air Products, Inc., Silwet L77 available from Witco Chemicals, TEGO Wet 270 available from Evonik, The Chemours Examples of suitable wetting agents include Triton X-100, FS-30, FS-34, FS-35, and FS3100 available from the Company. Wetting agents may comprise up to about 20% by weight of the total mixture.

[0016] The above composition is typically applied to the conductive material of a substrate using a method capable of applying a thin, uniform coating of primer material to the conductive material. One example of such a method is inkjet printing. Other methods include spray, ribbon, slot, die, and gravure coating. To be usable in these methods, the composition is optimized for each application, for example, by adjusting the viscosity. The polymer can be tailored to achieve the optimal coating amount of primer material at the target viscosity for the application method, for example, by adjusting the type of monomer or catalyst, or the content or activity of the activator. The precursor is typically applied to a thickness of 2 μm to 50 μm in direct contact with the conductive material of the substrate, thereby covering at least a portion of the conductive material to be patterned into a circuit.

[0017] After application of the precursor material, the precursor material is solidified to form the primer material. The substrate may be subjected to a drying process that includes elevated temperatures up to about 150°C (e.g., about 80°C) and / or reduced pressure, such as a negative pressure of up to about 250 Torr. Additionally, if polymerizable components requiring activation are present, the substrate may be exposed to ultraviolet light to activate polymerization of such components. The resulting primer is coated as a solid onto the conductive material of the substrate and reacts with the second component of a two-component system, which is applied in a patterned fashion, to form a patterned mask.

[0018] At 104, an optional transition material is applied to the primer material. The transition material prepares the primer surface for optimal adhesion and acceptance of subsequently applied pattern material. For example, a solvent remover can be applied to the primer material to dissolve slow-evaporating solvent species in a more volatile material, accelerating removal. Alternatively, an adhesion promoter can be applied. The adhesion promoter can include functional groups capable of bonding with the primer material and the pattern material. Examples of adhesion promoters that can be used include peptides with acid- and base-reactive functional groups and silane coupling agents. The transition material can be functionally similar to the primer material but have different composition, physical properties, or chemical properties. For example, a second polymeric primer material can be applied with the same composition but different molecular weight or reactive site density. Alternatively, the second polymeric primer material can be a different polymer from the underlying polymeric primer material. The optional transition material is optionally used to enhance the bonding of the pattern material to the primer material. The transition material can also be used to adjust the thickness, density, and surface height nonuniformity of the primer material.

[0019] At 106, a pattern material is applied to the transition material or directly to the primer and reacted with the primer. The pattern material is applied in a patterned manner to form a pattern of acid-resistant mask material that covers some of the conductive material but not others. The pattern material is applied as a liquid, for example, using inkjet printing or other liquid printing pattern application methods. The pattern material includes a material that reacts with the polycation species of the primer to form an acid-resistant polymer. This material is therefore the second component of a two-component system that includes a primer material and a primer-reactive material. The primer-reactive material can be an anionic or polyanionic material (i.e., a multi-acid), such as polyacrylic acid or polymethacrylic acid. Mixed polyalkylacrylic acids can also be used as copolymers or multipolymers, or as homopolymers and / or mixtures of copolymers and multipolymers. Other suitable polyanionic materials include polyanionic celluloses (i.e., ANTISOL polyanionic celluloses from Dow Chemical Co.) and polystyrene sulfonates. The polyanionic species is used as an aqueous solution, which may contain wetting agents, colorants, etc., as described above.

[0020] A base that is at least partially soluble or miscible in water is added to the pattern material to activate the polyanion species in the pattern material. The strong base increases the reactivity of the pattern material with the primer material or the mixture of the primer material and the transition material. It is believed that the strong base removes a proton from the polyanion species, producing an anion that is highly reactive with the primer material or the mixture of the primer material and the transition material.

[0021] To prevent the ink composition from changing significantly when applied to the substrate, it is desirable for the base to have a pH of 7.2 to 12 and relatively low volatility. Low toxicity is also an advantage. Suitable materials for use as strong bases include alkylamines (NRs). 1 R 2 R 3 , Alkanolamine NR 4 R5 R 6 and organic cyclic amines such as pyrrole, pyrrolidine, piperidine, imidazole, pyrazole, pyridine, purine, diazine, and triazine. 1 R 2 R 3 In R 1 , R 2 , R 3 At least one of R consists of carbon and hydrogen, 1 , R 2 , R 3 may be only hydrogen, and the general formula is C x H y N z (where x is 3 to 6, i.e., alkylamine having 3 to 6 carbon atoms, z is 1 or 2, and y is 2x + 2 + z). Alkanolamine NR 4 R 5 R 6 In R 4 , R 5 , R 6 At least one of the groups is a hydroxyalkyl group C a H 2a OH and R 4 , R 5 , R 6 may be hydrogen only, and R 4 , R 5 , R 6 At least one of the alkyl groups C a H 2a+1 Examples of such materials include isopropylmethylamine, butylamine, 3-dimethylamino-2-propanol, and triethanolamine. A small amount of ammonia, for example, about 10% by weight or less of the total composition, may be included in the above materials as a stabilizer, provided that the loss of ammonia through evaporation does not significantly change the properties of the pattern material. Carbon-containing bases have low volatility and contribute to the thermal stability of the pattern material. Using a low-molecular-weight base at low temperatures can minimize base volatilization and changes in the composition of the pattern material. At higher temperatures, a stronger base with a higher molecular weight can be used.

[0022] The pattern material is applied in a precision pattern deposition process such as inkjet printing, in which the pattern material is applied as individual droplets, creating fine, uniform features on the order of 10 μm. In this manner, a masking pattern can be formed on the conductive material of the substrate. Precision pattern deposition of the liquid can be performed using inkjet printers available from Kateeva, Inc., Newark, California, or systems available from other manufacturers.

[0023] The pattern material is fixed in place by a substantially instantaneous reaction with the primer, forming rigid or semi-rigid polymer features in a pattern. The polymer features formed by the reaction of the pattern material with the primer material are acid-resistant, allowing them to be used as a mask during an acid treatment to remove unreacted primer material and exposed conductive material. If a radiation-activated component is included, the pattern material can optionally be exposed to ultraviolet radiation to increase its hardness or rigidity. For example, after depositing the pattern material on the primer material, the substrate can be irradiated with 395 nm light for 30 seconds to increase the hardness of the patterned polymeric material. Increasing the hardness can improve the acid resistance of the patterned polymeric material.

[0024] At 108, the substrate is treated with an acid to remove the primer material and expose portions of the underlying conductive material. Weak acid solutions such as acetic acid or citric acid can be used. Strong acids can also be used, including HCl, optionally with salts such as ferric chloride and cupric chloride, acetic acid, nitric acid, chloric acid, perchloric acid, iodic acid, bromic acid, and sulfuric acid, as well as the above acids, optionally with suitable salts (i.e., ferric or copper salts). Suitable acids have a pH of 1.75 or higher in water. The conductive material not covered by the patterned polymeric material is exposed, while the conductive material covered by the patterned polymeric material remains covered due to the acid resistance of the patterned polymeric material. The substrate can be immersed in the acid solution, or the acid or its solution can be sprayed onto the surface of the substrate coated with the primer material. The solution concentration can be around 1 M, although lower concentrations can also be used. An electric potential can optionally be applied to increase the etching rate. For example, electrodes can be attached to opposing edges of the conductive material and a DC or AC electric field can be applied to promote reaction between the metal and ions in the etching solution. For example, if not immediately followed by subsequent processing of the substrate, the process at 108 can also partially remove the primer material, leaving behind a thin coating to protect the conductive material from environmental factors. Care must be taken, especially when using strong acids, to avoid damaging the acid-resistant pattern and to avoid uneven etching of the conductive material.

[0025] The acid treatment step can be performed in one application or, optionally, in two applications. For example, the first application of acid can be a weak acid and the second application of acid can be a strong acid. In another example, the primer material can be removed with a water treatment without using acid, and then etching can be performed with an acid application. In another example, a strong acid can be applied, followed by a weak acid or water application. In this case, the strong acid can create a pattern and etch the exposed conductive material, and the weak acid or water can remove the etching byproducts and any remaining pattern material.

[0026] At 110, the etching is stopped and the substrate is washed with water to remove the etchant from the substrate. An alcohol, such as isopropyl alcohol, may be included in the solution along with the water as a cleaning solution. The patterned polymer may remain on the printed circuit board, but may be removed by washing with water. In this case, increasing the temperature and / or pH may accelerate removal. Protic co-solvents, such as alcohol or ammonia, can also accelerate dissolution. The underlying primer material is also typically water-soluble, but removal can be facilitated by using elevated temperatures and / or polar aprotic solvents, such as pyridine or N-methylpyrrolidone.

[0027] The result is a printed circuit board with a pattern of conductive microcircuits. At this point, the microcircuits can be encapsulated. Alternatively, a second resin substrate can be laminated on top of the first substrate with the microcircuits to create a three-dimensional circuit structure.

[0028] FIG. 2 is a flowchart outlining another embodiment of a method 200. Method 200 is a method for forming a pattern ink for forming fine circuits on a printed circuit board. In 202, a water-miscible base is added to a volume of water to form a base mixture. The base may be an alkylamine, alkanolamine, or organic heterocyclic amine. The base generally has low volatility, e.g., a boiling point between room temperature and about 180° C., a pH in water between 7.5 and 12, and preferably, but not necessarily, has low or no toxicity.

[0029] Suitable alkylamines include NR 1 R 2 R 3 and R 1 , R 2 , R 3 at least one of R is carbon and hydrogen; 1 , R 2 , R 3 may be only hydrogen, and the general formula is C x H y N zwhere x is 3 to 6, i.e., alkylamines having 3 to 6 carbon atoms; z is 1 or 2, i.e., monoamines and diamines; and y is 2x + 2 + z. Examples include isopropylmethylamine, diethylamine, triethylamine, and trimethylamine. Suitable alkanolamines have the general structure NR 4 R 5 R 6 and R 4 , R 5 , R 6 At least one of the groups is a hydroxyalkyl group C a H 2a OH and R 4 , R 5 , R 6 may be only hydrogen, and R 4 , R 5 , R 6 One of the alkyl groups is C a H 2a+1 Examples include triethanolamine and 3-dimethylamino-2-propanol. Suitable organic cyclic amines include pyrrole, pyrrolidine, piperidine, imidazole, pyrazole, pyridine, purine, diazine, and triazine. Mixtures of these compounds can be used, and a small amount of ammonia can also be included in the mixture. The basic mixture is generally prepared to a pH of 7.5 to 12.

[0030] At 204, a polyanionic material is added to the base mixture. The polyanionic material is a polymer with multiple sites capable of removing protons. The polyanionic material can be one or more of polyacrylic acid, polymethacrylic acid, mixed polyalkylacrylic acid as a copolymer or multipolymer, or as a homopolymer and / or a mixture of copolymers and multipolymers, and polyanionic cellulose (i.e., Antisol polyanionic cellulose from Dow Chemical Company). Typically, the polyanionic material is added as a solid or an aqueous dispersion.

[0031] In 206, the polyanionic material is dissolved in the base mixture. The base mixture to which the polyanionic material has been added is mixed for, for example, 2 to 24 hours. Heat may be applied to this mixture to heat it to about 10°C to 20°C above ambient temperature.

[0032] At 208, optional additional solvents, surfactants, or co-solvents may be added to adjust viscosity, pH, surface tension, or other properties for processing. Water can be used along with other solvents such as alcohols, e.g., glycols. However, any suitable solvent can be used to create a mixture according to the concepts described herein. A base is selected along with the solvent to dissolve the polyanionic material depending on the deprotonation strength of the base in the solvent.

[0033] An example of a formulation made by method 200 is shown below. The formulation number is written at the top of the table and the component number is written on the side. The components are as follows: Component 1 - Joncryl 8085 (Polyacrylic Acid in Ammonium Hydroxide Solution), Component 2 - Joncryl 682 (Polyacrylic Acid), Component 3 - Propylene Glycol, Component 4 (Base) - Aminomethylpropanol, Component 5 (Base) - Isopropylmethylamine, Component 6 (Base) - Ethanolamine, Component 7 (Base) - Isobutylamine, Component 8 (Base) - 1-Amino-2-propanol, Component 9 (Base) - Sec-Butylamine, Component 10 (Base) - 3-Dimethylamino-2-propanol, Component 11 - Ethylenediaminetetraacetic acid (EDTA), Component 12 - Bayscript Cyan, Component 13 - Bayscript Blue, Component 14 - TEGO Wet 500, Component 15 - Deionized Water. In each example, a base is added to water to form a base mixture, and then the polyacrylic acid component is added to the base mixture to form a dispersion mixture. The dispersion mixture is stirred for a period of time to dissolve the polyanionic material. The other ingredients are then added in any order. Example formulations are as follows: [Table 1]

[0034] The inks made by method 200 of Figure 2 can be used as pattern materials in method 100 of Figure 1. Such inks can be made before use to form circuit patterns and can be stored or used for up to one month. The inks can be mixed continuously during use to form pattern materials, or they can be mixed intermittently between uses.

[0035] The amount of base required depends on the dissociation constant of the base, the relative acid strength of the conjugated anions, and the polyanionic material. Stronger bases produce more anions with weaker acids. Higher molecular weight polyanions require larger amounts and / or stronger anions to dissolve. While bases with low toxicity can be conveniently selected, the base can be selected based on its ionic nature. Bases are generally selected based on their ability to attract protons from the polyanionic material as well as their solubility in the solvent or solvent mixture used in the ink. The amount of base required depends on the concentration of acid groups in the polyanionic material and the dissociation constant of the base. Ideally, the base also does not substantially react with the polycationic material used as a primer, or the amount of base used is such that only a small amount of excess base remains after interacting with the polyanionic material.

[0036] While the above describes embodiments of the present invention, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, which is defined by the following claims.

Claims

1. 1. A method, comprising: depositing a conductive material on a substrate; applying a primer material soluble in water or aqueous acid onto the conductive material; and applying an acid-resistant pattern material, which reacts with the primer material according to a pattern, onto the applied primer material by inkjet printing to form an acid-resistant mask. The pattern material comprises a basic solution of a polyanionic material, the base being (1) a mixture of alkylamines, at least one of which has the structure NR １ R ２ R ３ and R １ ~R ３ wherein at least one of the alkanolamines is carbon and hydrogen; and (2) a mixture of alkanolamines wherein at least one of the alkanolamines is structure NR ４ R ５ R ６ and R ４ ~R ６ At least one of the groups is a hydroxyalkyl group C ａ H ２ａ OH, or (3) an organic cyclic amine; The method further includes exposing the substrate to an acid to etch the exposed portions of the conductive material.

2. The method of claim 1 , wherein the pattern material further comprises ammonia.

3. 3. The method of claim 2, wherein the pattern material comprises 10% or less by weight of ammonia.

4. 10. The method of claim 1, wherein the primer material is applied by inkjet printing.

5. The method of claim 4 , wherein the pattern material comprises polyacrylic acid or polyanionic cellulose.

6. The method of claim 3 , wherein the primer material comprises a polycationic polymer.

7. 5. The method of claim 4, wherein exposing the substrate to an acid comprises applying a first acid to the substrate and then applying a second acid.

8. The method of claim 1 , wherein the primer material comprises a polycation-based material.

9. 10. The method of claim 1, wherein the base comprises an organic cyclic amine selected from the group consisting of pyrrole, pyrrolidine, piperidine, imidazole, pyrazole, pyridine, purine, diazine, triazine, and combinations thereof.

10. 2. The method of claim 1, wherein the base has a pH of 7.2 to 12.

11. 10. The method of claim 1, wherein the base is a mixture of alkylamines, each component having from 3 to 6 carbon atoms.

12. 1. A method, comprising: depositing a conductive material onto a substrate; inkjet printing an acid-soluble primer material comprising a polycationic material to cover the conductive material; and inkjet printing an acid-resistant pattern material, including a polyanionic material, ammonia, and a base, onto the primer material in accordance with a pattern to form an acid-resistant mask, wherein the base is (1) a mixture of alkylamines, at least one of which has the structure NR １ R ２ R ３ and R １ ~R ３ wherein at least one of the alkanolamines consists of carbon and hydrogen; and (2) a mixture of alkanolamines, at least one of which consists of the structure NR ４ R ５ R ６ and R ４ ~R ６ At least one of the groups is a hydroxyalkyl group C ａ H ２ａ (3) an organic cyclic amine; or (4) a combination thereof.

13. 13. The method of claim 12, wherein the pattern material comprises 10% or less by weight of ammonia.

14. 13. The method of claim 12, wherein the polyanionic material is polyacrylic acid or a polyanionic cellulose.

15. 13. The method of claim 12, wherein the primer material is water-soluble and the polycation-based material comprises a polycation polymer.

16. 16. The method of claim 15, wherein the polycationic polymer is selected from polyethyleneimine, polyspermine, polyspermidine, polyputrescine, polyamidoamine, polyvinylpyrrolidone, polydiallyldimethylammonium chloride, polylysine, polytriazine, polyaminal, polythioaminal, chitosan, gelatin, cellulose, starch, pectin, polypeptide, alginic acid, and combinations thereof.

17. 13. The method of claim 12, wherein the primer material includes an organic, water-miscible co-solvent.

18. 1. A method of forming a printed wiring board, the method comprising: depositing a conductive material on a substrate; applying an acid-soluble primer material over the entire area of ​​the conductive material by inkjet printing; and applying an acid-resistant pattern material containing a polyanionic material, ammonia, and a base onto the primer material by inkjet printing in a pattern to form an acid-resistant mask, wherein the base is (1) a mixture of alkylamines, at least one of which has the structure NR １ R ２ R ３ and R １ ~R ３ wherein at least one of the alkanolamines is carbon and hydrogen; and (2) a mixture of alkanolamines wherein at least one of the alkanolamines is of the structure NR ４ R ５ R ６ and R ４ ~R ６ At least one of the groups is a hydroxyalkyl group C ａ H ２ａ (3) an organic cyclic amine; or (4) a combination thereof; The method further includes exposing the substrate to an acid to remove exposed portions of the conductive material.

19. 20. The method of claim 18, wherein the primer material comprises a solvent selected from monoethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, glycerin, aliphatic amides, aromatic amides, carboxylic acids, ethers, esters, alcohols, organic sulfides, organic sulfoxides, sulfones, carbitol, butyl carbitol, cellosolve, amino alcohols, ketones, N-methylpyrrolidone, cyclohexylpyrrolidone, hydroxy ethers, lactones, imidazoles, and mixtures thereof.

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