Inkjet printed circuit board

Abstract

The substrate processing method described herein includes depositing a conductive material on a substrate, applying a primer material soluble in water or an aqueous acid solution to the conductive material, and inkjet printing an acid-resistant pattern material reactive with the primer material onto the primer material in a pattern to form an acid-resistant mask, the pattern material comprising a basic solution of a polyanionic material, the base being a NR 1 R 2 R 3 and an alkylamine having the structure: 1 , R 2 , and R 3 an alkylamine in which at least one of 4 R 5 R 6 Alkanolamines having the general structure: 4 , R 5 , and R 6 At least one of the groups is a hydroxyalkyl group C a H 2a OH, or an organic cyclic amine, and exposing the substrate to an acid to etch the exposed portions of the conductive material.

Description

Technical Field

[0001] The embodiments described in this specification generally relate to the manufacture of circuit boards using an inkjet printing process. This application describes a novel method and ink for inkjet printed circuit boards.

Background Art

[0002] A printed circuit board (PCB) is generally created by forming a conductive sheet, for example made of copper, on a non-conductive substrate, masking a part of the conductive sheet, and etching the unmasked part to form a pattern of conductive wiring on the non-conductive substrate. Masking is usually performed using an acid-resistant resin material. Copper is usually etched using an acidic solution. The mask material protects the copper under the mask material from being etched by the acid. In a commonly used process, the mask material is printed on the conductive sheet by an inkjet printing process. Printed circuit board products may include a single substrate with circuits printed on one or both sides, or in a composite device, multiple substrates with multiple circuits may be stacked.

[0003] In an inkjet process for forming a negative image of a circuit pattern on a printed circuit board device, a primer material is coated on the substrate, and then a material reactive with the primer is applied in a pattern by inkjet printing. This reactive material reacts with the primer and adheres at a predetermined position by the reaction. The primer is usually a polycationic material such as polyethyleneimine, a divalent salt matrix, a vinyl pyrrolidone polymer, etc. The pattern material is an acid-resistant material reactive with the polycationic material. Examples of such materials include acrylic resin and styrene-acrylic resin. The primer is usually coated and dried on the metal surface. Then, the pattern material is applied in a pattern to react with the primer and adhered at a predetermined position. The pattern material is usually applied in a basic state with a pH above 7.0 to react with the primer. An acid such as HCl can also be added to the primer to accelerate the reaction.

[0004] The base contained in the pattern material is often volatile. For example, ammonia may be used. When the base contained in the pattern material is volatile, it becomes difficult to use as an inkjet material. This is because when the volatile material comes into contact with the outside air, the composition and properties of the inkjet material change, and the material coating by inkjet printing becomes unstable. The viscosity of the material changes, and the material coating on the substrate becomes inaccurate. As a result, the pattern formed on the conductive material often deviates from the tolerance. In the field of inkjet printed circuit boards, a new method and material for accurately patterning a conductive coating are required.

Summary of the Invention

[0005] According to the embodiments described herein, there is provided a method including depositing a conductive material on a substrate, applying a primer material soluble in water or an acidic aqueous solution to the conductive material, inkjet printing an acid-resistant pattern material reactive with the primer material on the primer material according to a pattern to form an acid-resistant mask, exposing the substrate to an acid, and etching an exposed portion 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 containing a polycationic material over the entire area of the conductive material, inkjet printing an acid-resistant pattern material containing a polyanionic material on the primer material according to a pattern to form an acid-resistant mask, exposing the substrate to an acid, and removing a part of the conductive material according to a pattern.

[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 containing a polycationic material and a solvent over the entire area of the conductive material, removing the solvent to solidify the primer material, inkjet printing an acid-resistant pattern material containing a polyanionic material on the solidified primer material according to a pattern to form an acid-resistant mask, exposing the substrate to an acid, and removing a part of the conductive material according to a pattern.

Brief Description of the Drawings

[0008] To enable a more detailed understanding of the above-described features of the present disclosure, the present disclosure outlined above will be described more specifically with reference to embodiments, and a part thereof is illustrated in the accompanying drawings. However, it should be understood that the accompanying drawings merely show exemplary embodiments and thus do not limit the scope, and other equally effective embodiments are also possible.

[0009]

Figure 1

[0010]

Figure 2

[0011] For ease of understanding, elements common between the drawings are denoted by the same reference numerals as much as possible. Elements and features of one embodiment can be incorporated into other embodiments as convenient without additional description.

Embodiments for Carrying Out the Invention

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

[0013] Figure 1 is a flowchart showing an outline of a method 100 according to an embodiment. At 102, a primer is formed on a conductive material layer of a substrate. The substrate can be made of any material as long as it serves as a base for the conductive material layer. For example, the substrate can be a conventional blank circuit board made of resin and optionally impregnated with polymer fibers. Also, the substrate can be a material such as glass or polymer film on which a circuit or microcircuit is formed. The conductive material layer is typically a metal or any conductive and acid-soluble material. As an example, copper is often used.

[0014] The primer is an ionic material that can be applied as a liquid and solidified as a layer. The primer material may be a polymer precursor or a polymer material dissolved in a solvent. The primer polymer is typically a polycationic polymer (i.e., polybasic), which is a polymer that can accept one or more protons to become a cation. The polycationic polymer has multiple arrangements that can accept protons from a proton donor to form ionic bonds or catalyze the formation of covalent or semi-covalent bonds. Examples of polymer materials that can be used as primer materials include polyethyleneimine, polyspermine, polyspermidine, polyputrescine (polybutanediamine), and other related polyamine polymers (which may be substantially linear or cross-linked), polyamidoamine, polyvinylpyrrolidone, polydiallyldimethylammonium chloride, polylysine, polytriazine, polyaminar, and polythioaminar, as well as natural and semi-synthetic polycationic materials such as chitosan, gelatin, cellulose, and starch derivatives such as dextran and dextrin, pectin, polypeptide, and alginic acid. These materials can be used as homopolymers, copolymers, or multipolymers and may be copolymerized, cross-linked, or dendrimerized with other monomers or polymers such as vinyl species (i.e., polyaminodiacrylate co-ester), epoxy species, urethane species, etc. Activators such as radical activators and co-activators (e.g., monomers in copolymerization systems such as epoxy-based and urethane-based) may be included as long as polymerizable substances such as vinyl species and epoxy species are included in the primer precursor. The polymeric primer material is usually acid-soluble, and the primer material that has not reacted with the pattern material can then be removed to expose the conductive material so that the conductive material can be etched.

[0015] The polymeric primer material is applied onto the conductive material of the substrate using an aqueous precursor containing the polymeric primer material. This aqueous precursor is applied as the first component of a two-component system for fixing the pattern of the acid-resistant mask onto the conductive material. As a typical example of the liquid medium for applying the primer material, a mixture of water and an organic and water-miscible co-solvent, 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, amino alcohol (i.e., aminomethylpropanol), ketones, N-methylpyrrolidone, cyclohexylpyrrolidone, hydroxyethers, lactones, imidazoles, and mixtures thereof can be mentioned. The non-aqueous component is usually contained from 0 wt% to about 50 wt%, and helps to dissolve other additives that can 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 Wet270 available from Evonik, Triton X-100, FS-30, FS-34, FS-35, FS3100 available from The Chemours Company can be mentioned. The wetting agent may be contained up to about 20 wt% of the total mixture.

[0016] The above composition is usually applied onto the conductive material of a substrate using a method capable of thinly and uniformly applying a primer material onto the conductive material. An example of such a method is inkjet printing. Other methods include spraying, ribbon, slot, die, and gravure coating. To be usable in such methods, the composition is optimized for each application, for example, by adjusting the viscosity. The above polymer can be adjusted according to the molecular weight and degree of crosslinking, for example, by adjusting the type of monomer, catalyst, or the content or activity of the activator, and can achieve an optimal coating amount of the primer material at a target viscosity according to the coating method. The precursor is usually applied in a thickness of 2 μm to 50 μm in direct contact with the conductive material of the substrate. Thereby, at least a part of the conductive material to be patterned as a circuit is covered.

[0017] After applying the precursor material, the formation of the primer material is completed when the precursor material is solidified. The substrate may be subjected to a drying process including heating up to a maximum of about 150 °C (for example, about 80 °C) and / or reducing the pressure such as a negative pressure of up to about 250 Torr. Also, when a polymerizable component that requires activation is included, the substrate may be exposed to ultraviolet light to activate the polymerization of such components. The obtained primer is coated as a solid onto the conductive material of the substrate and reacts with the second component of the two-component system applied in a pattern to form a pattern mask.

[0018] In 104, an optional transition material is applied to the primer material. The transition material can condition the surface of the primer so as to accept and optimally bond to the pattern material to be applied later. For example, a solvent remover can be applied to the primer material to accelerate removal by dissolving a slowly evaporating solvent species in a more volatile material. As another example, an adhesion promoter may be applied. The adhesion promoter may include functional groups capable of bonding to the primer material and the pattern material. Examples of adhesion promoters that can be used include peptides having acid and base reactive functional groups and silane coupling agents. The transition material may be a material that is functionally similar to the primer material but has different composition, physical properties, and chemical properties. For example, a second polymeric primer material having the same composition but different molecular weight and reaction site density may be applied. Alternatively, the second polymeric primer material may be a polymer different 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. Also, the transition material can be used to adjust non-uniformities in the thickness, density, and surface height of the primer material.

[0019] In 106, the pattern material is applied to the transition material or directly to the primer and reacted with the primer. By applying the pattern material in a pattern, a pattern of an acid-resistant mask material is formed that covers part of the conductive material and not the other parts. The pattern material is applied as a liquid using, for example, an inkjet printing or other liquid printing-based pattern application method. The pattern material includes a material that reacts with the polycationic species of the primer to form an acid-resistant polymer. Thus, this material is the second component of a two-component system including the primer material and the primer-reactive material. The primer-reactive material is an anionic or polyanionic material (i.e., a polyacid) such as polyacrylic acid or polymethacrylic acid. Mixed polyalkylacrylic acids can also be used as copolymers or multipolymers, or as mixtures of homopolymers and / or copolymers and multipolymers. Other suitable polyanionic materials include polyanionic cellulose (i.e., ANTISOL polyanionic cellulose from Dow Chemical Co.) and polystyrene sulfonate. The polyanionic species is used as an aqueous solution, which may contain a wetting agent, a coloring agent, etc. as described above.

[0020] A base that is at least somewhat soluble or miscible in water is added to the pattern material to activate the polyanionic species in the pattern material. The strong base enhances the reactivity between the pattern material and the primer material or the mixed material of the primer material and the transition material. It is thought that the strong base removes protons from the polyanionic species and generates anions with high reactivity with the primer material or the mixed material of the primer material and the transition material.

[0021] To ensure that the ink composition does not change significantly when applied to the substrate, the base preferably has a pH of 7.2 to 12 and relatively low volatility. It is also advantageous that it has low toxicity. Suitable materials for use as strong bases include alkylamine NR 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. In the alkylamine NR 1 R 2 R 3 wherein at least one of R 1 R 2 R 3 consists of carbon and hydrogen, and one or more of R 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, that is, an alkylamine having 3 to 6 carbon atoms, z is 1 or 2, and y is 2x + 2 + z). In the alkanolamine NR 4 R 5 R 6 wherein at least one of R 4 R 5 R 6 is a hydroxyalkyl group C a H 2a OH, and one or more of R 4 R 5 R 6 may be only hydrogen, and one or more of R 4 R 5 R 6 may be an alkyl group C a H 2a+1 . Examples of the materials include isopropylmethylamine, butylamine, 3-dimethylamino-2-propanol, and triethanolamine. A small amount of ammonia, for example, ammonia of about 10% by weight or less of the whole composition, may be included in the above materials as a stabilizer to such an extent that the disappearance of ammonia by vaporization does not significantly change the properties of the pattern material. The base containing carbon has low volatility and contributes to the thermal stability of the pattern material. When using a low molecular weight base at a low temperature, the volatilization of the base and the compositional change of the pattern material can be minimized. When the temperature is higher, a stronger base with a higher molecular weight can be used.

[0022] The pattern material is applied in a precise pattern deposition process such as inkjet printing. In inkjet printing, the pattern material is applied as individual droplets to form fine and uniform features on the order of 10 μm. In this way, a masking pattern can be formed on the conductive material of the substrate. Precise pattern deposition of the liquid can be performed using an inkjet printer available from Kateeva, Inc. in Newark, California, or a system available from other manufacturers.

[0023] The pattern material adheres to a predetermined position by a substantially instantaneous reaction with the primer, forming a patterned rigid or semi-rigid polymer feature. Since the polymer feature formed by the reaction between the pattern material and the primer material is acid-resistant, it can be used as a mask in an acid treatment for removing unreacted primer material and exposed conductive material. If components activated by radiation are included, the pattern material can optionally be exposed to ultraviolet radiation to increase hardness or rigidity. For example, after depositing the pattern material on the primer material, the substrate may be irradiated with light of 395 nm for 30 seconds to increase the hardness of the patterned polymer material. By increasing the hardness, the acid resistance of the patterned polymer material can be improved.

[0024] In 108, the substrate is treated with an acid to remove the primer material and expose a part of the underlying conductive material. A weakly acidic solution such as acetic acid or citric acid can be used. Strong acids can also be used. Examples of strong acids include HCl, HCl optionally containing salts such as ferric chloride and cupric chloride, acetic acid, nitric acid, chloric acid, perchloric acid, iodic acid, bromic acid, sulfuric acid, and the above acids optionally containing suitable salts (i.e., ferric salts or copper salts). A suitable acid has a pH of 1.75 or more in water. The conductive material not covered by the patterned polymer material is exposed, and the conductive material covered by the patterned polymer material remains covered because the patterned polymer material is acid-resistant. The substrate may be immersed in the acidic solution, or the acid or its solution may be sprayed onto the surface of the substrate coated with the primer material. The concentration of the solution may be about 1M, but it is also possible to use a lower concentration solution. In order to increase the etching rate, a potential may be applied in some cases. For example, electrodes can be attached to each of the opposing edges of the conductive material, and a direct current or alternating current electric field can be applied to promote the reaction between the metal and the ions in the etching solution. For example, when the treatment of the substrate is not immediately continued after 108, in some cases, the primer material may be partially removed by the treatment of 108, and a thin coating for protecting the conductive material from environmental factors may be left. Especially when using strong acids, care is needed not to damage the acid-resistant pattern and not to make the etching of the conductive material non-uniform.

[0025] The acid treatment step can be performed in one application or optionally in two applications. For example, a weak acid can be used for the first application of the acid, and a strong acid can be used for the second application of the acid. In another example, the primer material can be removed by water treatment without using an acid, and then an acid can be applied for etching. In another example, a weak acid or water can be applied after applying a strong acid. In this case, a pattern can be generated by the strong acid, the exposed conductive material can be etched, the etching by-products can be removed by the weak acid or water, and the remaining pattern material can also be removed.

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

[0027] As a result, a printed circuit board with a patterned conductive fine circuit is obtained. At this point, the fine circuit can be encapsulated. Alternatively, a second resin substrate can be laminated on the first substrate provided with the fine circuit to construct a three-dimensional circuit structure.

[0028] Figure 2 is a flowchart showing an overview of method 200 according to another embodiment. Method 200 is a method for forming a pattern ink for forming a fine circuit on a printed circuit board. At 202, a water-miscible base is added to a certain amount of water to form a base mixture. The base is an alkylamine, an alkanolamine, or an organic heterocyclic amine. The base generally has low volatility, for example, a boiling point from room temperature to about 180 °C, a pH in water of 7.5 to 12, and is preferably low-toxic or non-toxic, although this is not essential.

[0029] A suitable alkylamine has the structure of NR 1 R 2 R 3 where at least one of R 1 , R 2 , R 3 is carbon and hydrogen, and one or more of R 1 , R 2 , R 3 may be only hydrogen, and the general formula is C x H y N z(wherein x is 3 to 6, i.e., an alkylamine having 3 to 6 carbon atoms, z is 1 or 2, i.e., a monoamine and a diamine, and y is 2x + 2 + z). Examples include isopropylmethylamine, diethylamine, triethylamine, and trimethylamine. A preferred alkanolamine has the general structure NR 4 R 5 R 6 wherein at least one of R 4 R 5 R 6 is a hydroxyalkyl group C a H 2a OH, one or more of R 4 R 5 R 6 may be only hydrogen, and one of R 4 R 5 R 6 may be an alkyl group C a H 2a+1 . Examples include triethanolamine and 3-dimethylamino-2-propanol. Preferred 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 adjusted to pH 7.5 to 12.

[0030] In 204, a polyanionic material is added to the base mixture. The polyanionic material is a polymer having a plurality of sites capable of removing protons. The polyanionic material can be one or more of polyacrylic acid, polymethacrylic acid, a copolymer or a multipolymer, or a mixed polyalkylacrylic acid as a homopolymer and / or a copolymer and a mixture of a copolymer and a multipolymer, and polyanionic cellulose (i.e., the antisol polyanionic cellulose of The Dow Chemical Company). Usually, the polyanionic material is added as a solid or an aqueous dispersion.

[0031] In 206, a polyanion-based material is dissolved in a base mixture. The base mixture added with the polyanion-based material is mixed, for example, for 2 to 24 hours. Heat may be applied to this mixture to heat it to about 10 °C to 20 °C higher than the ambient temperature.

[0032] In 208, a solvent, a surfactant, or a co-solvent may be further optionally added to adjust the viscosity, pH, surface tension, or other properties for the treatment. Water can be used together with other solvents such as alcohols, for example, glycol. It should be noted that any suitable solvent can be used to create a mixture according to the concepts described herein. The base is selected together with the solvent so as to dissolve the polyanion-based material according to the deprotonation strength of the base in the solvent.

[0033] The formulation examples created by method 200 are shown below. The formulation numbers are described at the top of the table and the component numbers are described 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) - secondary-butylamine, Component 10 (base) - 3-dimethylamino-2-propanol, Component 11 - ethylenediaminetetraacetic acid (EDTA), Component 12 - Bayscript Cyan, Component 13 - Bayscript Blue, Component 14 - TEGO Wet500, Component 15 - deionized water. In each example, a base is added to water to form a base mixture, and then a polyacrylic acid component is added to the base mixture to form a dispersion mixture. The dispersion mixture is stirred for a certain period of time to dissolve the polyanion-based material. Then, other materials are added in any order. The formulation examples are as follows.

Table 1

[0034] The ink prepared by Method 200 in FIG. 2 can be used as a pattern material in Method 100 in FIG. 1. Such ink can be prepared before being used for forming a circuit pattern and can be stored or used for up to one month. The ink may be continuously mixed during use to form a pattern material or may be intermittently mixed during periods of non-use.

[0035] The required amount of base depends on the dissociation constant of the base, the relative acid strength of the conjugate anion, and the polyanion-based material. The stronger the base, the more anions will be produced even with a weaker acid. To dissolve a polyanion with a high molecular weight, a larger amount and / or a stronger anion is required. A base with low toxicity can be selected for convenience, but the base can be selected according to its ionicity. Bases are generally selected according to their ability to attract protons from the polyanion-based material and their solubility in the solvent or solvent mixture used in the ink. The required amount of base depends on the concentration of the acid groups of the polyanion-based material and the dissociation constant of the base. Ideally, the base also either does not substantially react with the polycation-based material used as a primer, or the amount of base used is such that only a very small amount of excess base remains after interacting with the polyanion-based material.

[0036] Although embodiments of the present invention have been described above, other and further embodiments of the present disclosure can be devised without departing from its basic scope, which is defined by the following claims.

Claims

1. Depositing a conductive material on a substrate; Applying a primer material soluble in water or an acidic aqueous solution to the conductive material; An acid-resistant pattern material reactive with the primer material is inkjet printed on the primer material according to a pattern to form an acid-resistant mask. The pattern material contains an ammonia and a basic solution of a polyanion-based material. The base is NR １ R ２ R ３ is an alkylamine having a structure of, where R １ 、R ２ 、and R ３ at least one of is an alkylamine of carbon and hydrogen, or NR ４ R ５ R ６ is an alkanolamine having a general structure of, where R ４ 、R ５ 、and R ６ at least one of is a hydroxyalkyl group C ａ H ２ａ OH is an alkanolamine, or an organic cyclic amine, and A method comprising exposing the substrate to an acid and etching an exposed portion of the conductive material.

2. The method according to claim 1, wherein the primer material is applied by inkjet printing.

3. The method according to claim 2, wherein the pattern material comprises polyacrylic acid or polyanion cellulose.

4. The method according to claim 3, wherein the primer material comprises a polycation polymer.

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

6. The method according to claim 1, wherein the primer material comprises a polycation-based material.

7. Depositing a conductive material on a substrate; Inkjet printing an acid-soluble primer material containing a polycation-based material over the entire area of the conductive material; An acid-resistant pattern material containing a polyanion-based material, ammonia, and a base is inkjet printed on the primer material according to a pattern to form an acid-resistant mask, and the base is NR １ R ２ R ３ is an alkylamine having a structure of, where at least one of R １ , R ２ , and R ３ is an alkylamine containing carbon and hydrogen, or NR ４ R ５ R ６ is an alkanolamine having a general structure of, where at least one of R ４ , R ５ , and R ６ is a hydroxyalkyl group C ａ H ２ａ OH, or an organic cyclic amine, and A method comprising exposing the substrate to an acid and removing a part of the conductive material according to the pattern.

8. The method according to claim 7, wherein the polyanion-based material is polyacrylic acid or polyanion cellulose.

9. The method according to claim 7, wherein the primer material comprises a polycation polymer.

10. The method according to claim 9, wherein the primer material comprises a co-solvent.

11. Depositing a conductive material on a substrate; Inkjet printing an acid-soluble primer material containing a polycation-based material and a solvent over the entire area of the conductive material; Removing the solvent to solidify the primer material; An acid-resistant pattern material containing a polyanion-based material, ammonia, and a base is inkjet printed on the cured primer material according to a pattern to form an acid-resistant mask, and the base is NR １ R ２ R ３ is an alkylamine having a structure of, where at least one of R １ , R ２ and R ３ is carbon and hydrogen, or NR ４ R ５ R ６ is an alkanolamine having a general structure of, where at least one of R ４ , R ５ and R ６ is a hydroxyalkyl group C ａ H ２ａ OH, or an organic cyclic amine, and A method for forming a printed circuit board, comprising exposing the substrate to an acid and removing a part of the conductive material according to the pattern.

12. The method according to claim 11, wherein exposing the substrate to an acid comprises exposing the substrate to a weak acid and then to a strong acid.

13. The method according to claim 11, further comprising treating the substrate with water to expose a part of the conductive material before exposing the substrate to the acid.

14. The method according to claim 11, further comprising washing the substrate with an alcohol solution after exposing the substrate to the acid.

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