JP5342258B2 - Desmear processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface processing method capable of forming a strong adhesive force between an insulating resin material and a plated coat, even for a base material of low surface roughness which is appropriate for a wiring handling a high-speed signal and a high-density wiring. <P>SOLUTION: A solvent mixture water solution containing an organic solvent of at least one kind is separated into two or more layers. The solvent mixture water solution having been separated into two or more layers is dispersed and emulsified to provide a swollen solvent mixture water solution. An insulating resin material is immersed into the swollen solvent mixture water solution for swelling treatment. The insulating resin material having been subjected to swelling treatment is etched to form a micro texture on the surface of insulating material. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a surface treatment method for an insulating resin of a printed wiring board in a build-up method, and in particular, an extremely fine texture can be formed on the resin surface, and plating made of resin and copper or the like without greatly roughening the resin surface The present invention relates to a desmear treatment method capable of obtaining adhesion with a film.

  With the rapid development of the electronics industry, demand for higher density and higher performance of printed circuit boards has increased, and demand has expanded greatly. In particular, with the miniaturization and thinning of mother wiring boards of the latest digital devices such as mobile phones, notebook computers, and cameras, there is an increasing demand for higher density and finer wiring patterns. In addition, there is an increasing demand for higher-frequency connections between mounted components, and a substrate with a small surface roughness (small irregularities) that is advantageous for handling high-speed signals is required. ing.

  Currently, as a mounting technique, a circuit board manufacturing method by a semi-additive method or a full additive method is frequently used.

  Generally, in the semi-additive method of the build-up method, a wiring board is formed by roughening the surface of an insulating resin material, applying a catalyst, performing electroless copper plating, and further performing electrolytic copper plating. In the full additive method, the surface of the insulating resin material is roughened, a catalyst is applied, and the wiring board is formed only by electroless copper plating. The adhesion between the insulating resin material and the plating film in the wiring board manufactured by these methods is obtained by the anchoring effect on the uneven anchors on the surface of the base material formed by roughening the surface of the insulating resin material. Yes.

  Insulating resin materials used in build-up methods often contain fillers, which improve the mechanical and electrical properties of the insulating resin, and at the same time, the filler is an insulating resin material. It also plays a role of generating an anchor during roughening (see, for example, Patent Document 1).

  As described above, the plating film formed by electroless plating or electrolytic plating treatment has obtained an adhesive force with the base material by the anchor effect of the insulating resin material. In order to handle and obtain high-density wiring (the wiring itself and the space between wirings are narrow), the surface roughness of the base material, that is, the unevenness that becomes the anchor tends to be small, and the base material with a small anchor effect is often used. There is a current situation that has been.

  However, such a base material with a small surface roughness cannot give sufficient adhesion to the plating film. As a result, even if the plating film is formed, the plating film is peeled off from the insulating resin material. Problem arises.

JP-A-11-0697900

  The present invention has been made in view of these conventional problems. Even a base material having a small surface roughness suitable for high-speed signals and high-density wiring has a strong adhesion between the insulating resin material and the plating film. An object is to provide a surface treatment method to be formed.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors conducted a desmear treatment in which an insulating resin material is subjected to a swelling treatment using a dispersion / emulsified solution of a solvent mixture separated into two or more layers. It has been found that the adhesion between the insulating resin material and the plating film can be obtained without increasing the surface roughness.

That is, in the swelling treatment method according to the present invention, a solvent mixture aqueous solution containing at least one organic solvent is separated into two or more layers by raising the temperature to a predetermined temperature or more, and the solvent mixture aqueous solution separated into two or more layers is used. Is dispersed or emulsified to obtain a swelling solvent mixture aqueous solution, and the insulating resin is immersed in the swelling solvent mixture aqueous solution to swell.

Moreover, the desmear treatment method according to the present invention is a surface treatment method for an insulating resin of a printed wiring board, and includes two layers by raising the temperature of a solvent mixture aqueous solution containing at least one organic solvent to a predetermined temperature or more. In the swelling treatment step in which the solvent mixture aqueous solution separated into two or more layers is dispersed or emulsified to obtain a swelling solvent mixture aqueous solution, and an insulating resin is immersed in the swelling solvent mixture aqueous solution to swell, and the swelling treatment step. And an etching treatment step for etching the swelling insulating resin.

  According to the present invention, since an extremely fine texture can be formed on the surface of the insulating resin material, a strong adhesive force can be formed between the resin and the plating film without greatly roughening the resin surface.

  Hereinafter, the surface treatment method according to the present embodiment will be described in detail.

  The surface treatment method according to the present embodiment is obtained by separating an aqueous solvent mixture solution containing at least one organic solvent into two or more layers and dispersing or emulsifying the aqueous solvent mixture solution separated into two or more layers. An aqueous solution is used as a swelling liquid (swelling solvent mixture aqueous solution), and the insulating resin material is subjected to a swelling treatment.

  The aqueous solvent mixture used for the surface treatment is a single layer below a predetermined temperature, but is adjusted by containing an organic solvent that separates from water by raising the temperature above the predetermined temperature. Separated into two or more layers by raising the temperature to a temperature or higher. Specifically, for example, a single layer is formed at 40 ° C. or lower, but an organic solvent is contained that is separated into two or more layers by raising the temperature to 40 ° C. or higher.

  In the surface treatment method according to the present embodiment, the swelling liquid is obtained by mechanically dispersing and emulsifying the solvent mixture aqueous solution separated into two or more layers by raising the temperature to a predetermined temperature or more. To swell the insulating resin material. Thus, by performing etching treatment on the insulating resin that has been subjected to swelling treatment, it is possible to form a very fine texture on the surface of the insulating resin material, and the plating film and insulating resin material formed by the subsequent plating treatment Can be firmly adhered to each other. Hereinafter, the surface treatment method according to the present embodiment will be described in more detail.

<Adjustment of swelling liquid>
First, the swelling liquid (swelling solvent mixture aqueous solution) for subjecting the insulating resin material to swelling treatment in the present embodiment will be described.

  In the surface treatment method according to the present embodiment, the swelling liquid is adjusted using an aqueous solvent mixture solution containing at least one organic solvent and separated into two or more layers by raising the temperature to a predetermined temperature or higher. . At least one organic solvent contained in the solvent mixture aqueous solution is an organic solvent effective to swell the resin substance, and is amphiphilic having both hydrophilic and hydrophobic properties. A solvent mixture aqueous solution that is separated from water by raising the temperature to a predetermined temperature or higher is used.

Specifically, as an organic solvent, ethylene glycol, ethylene glycol monoalkyl ether, ethylene glycol dialkyl ether, diethylene glycol, diethylene glycol monoalkyl ether, diethylene glycol dialkyl ether, triethylene glycol, triethylene glycol monoalkyl ether, triethylene glycol dialkyl ether, propylene glycol, propylene glycol monoalkyl ether, propylene glycol dialkyl ether, dipropylene glycol, dipropylene glycol monoalkyl ethers, dipropylene glycol dialkyl ethers, glycol monoalkyl ethers, polyethylene glycol, polyethylene glycol monoalkyl ethers, polyethylene grayed Call dialkyl ethers, pyrrolidone, pyrrolidine, can be used at least one selected from the group consisting of a lactone, or the like.

  The concentration of the organic solvent compound in the solvent mixture aqueous solution is preferably about 50 to 900 g / L, and more preferably about 200 to 700 g / L. If the concentration of the organic compound is too low, the insulating resin material cannot be sufficiently swollen, the surface is not sufficiently roughened, and the plating film is liable to swell. On the other hand, when the concentration of the organic compound is too high, surface roughening proceeds excessively, the surface roughness becomes large, and it is difficult to obtain a good plating appearance.

  Since the organic solvent aqueous solution containing at least one of these organic solvents has amphiphilic properties, it is separated from water by raising the temperature to a predetermined temperature or higher, and two or more layers are formed. Form. Specifically, although depending on the type of organic solvent constituting the solvent mixture aqueous solution, the solvent mixture aqueous solution is separated into two or more layers by raising the temperature to about 40 to 90 ° C. The temperature to be raised depends on the type of the solvent constituting the solvent mixture aqueous solution and also on the mixing ratio with water, and is adjusted as appropriate according to these factors.

  In such a solvent mixture aqueous solution containing at least one organic solvent as described above and separated into two or more layers by raising the temperature, by raising the temperature to a predetermined temperature, very fine particles composed of the organic layer are formed. Will be formed. In the surface treatment method according to the present embodiment, by using this solvent mixture aqueous solution, in the swelling treatment described later, the generated ultrafine organic layer particles act on the minute portions on the surface of the insulating resin material to swell. In the subsequent etching roughening step, it is considered that the etching holes are formed only at the locations where the fine particles acted.

  Further, the aqueous solvent mixture solution may further contain a water-soluble metal hydroxide or a water-soluble metal salt as necessary. By including a water-soluble metal hydroxide or water-soluble metal salt in the solvent mixture aqueous solution, layer separation can be facilitated by raising the temperature of the solvent mixture aqueous solution to a predetermined temperature or more, and a finer organic layer. To form particles.

Specifically, the water-soluble metal hydroxide is not particularly limited, and NaOH, KOH, LiOH, Ca (OH) ₂ , Mg (OH) _{2, and the} like can be used. As Na ₂ SO ₄ , NaCl, Na ₃ PO ₄ , Na ₂ HPO ₄ , NaH ₂ PO ₄ , K ₃ PO ₄ , K ₂ HPO ₄ , KH ₂ PO ₄ , LiCl, Li ₃ PO ₄ , Li ₂ HPO ₄ , LiH ₂ PO ₄ , NaH ₂ PO ₂ , CaCl ₂ , MgCl ₂ , AlCl ₃ , Al (NO ₃ ) ₃ , Al ₂ (SO ₄ ) ₃ , ZnCl ₂ , Zn (NO ₃ ) ₂ , ZnSO ₄ , CuCl ₂ , Cu (NO ₃ ) ₂ , CuSO ₄ , NiCl ₂ , NiSO ₄ , Ni (NO ₃ ) ₂ , CoCl ₂ , CoSO ₄ , Co (NO ₃ ) _2, etc. It can be used alone or in combination of two or more.

  The concentration of these water-soluble metal hydroxides or water-soluble metal salts in the solvent mixture aqueous solution is preferably about 0.1 to 100 g / L, more preferably about 0.3 to 30 g / L. preferable. If the concentration of the water-soluble metal hydroxide or the water-soluble metal salt is too low, the effect of promoting the layer separation of the solvent mixture aqueous solution is not sufficiently exhibited. On the other hand, when the concentration is too high, the surface roughening proceeds excessively and the surface roughness increases.

  Next, a swelling solvent mixture aqueous solution (swelling liquid) is prepared by mechanically dispersing or emulsifying the solvent mixture aqueous solution separated into two or more layers produced as described above. Since this dispersion / emulsification treatment needs to be performed in a state where the above-mentioned aqueous solvent mixture solution is separated into two or more layers, the dispersion / emulsification treatment is carried out at a predetermined temperature or higher, which is increased to separate the two or more layers.

  As a method of mechanically dispersing or emulsifying the solvent mixture aqueous solution separated into two or more layers, it can be dispersed or emulsified by a known mechanical method.

  Specifically, for example, when a normal stirrer is used, stirring is performed so that the tip speed of blades such as propeller blades, turbine blades, and paddle blades is 10 m / sec or less. Moreover, when using a high-speed rotation centrifugal radiation type stirrer-toothed disk impeller, stirring is performed by rotating the blade tip at a high speed of 10 m / sec to 30 m / sec. In addition to rotating the stirring blade at high speed, in order to prevent excessive cavitation in the vicinity of the outer periphery of the stirring blade, by using a high-speed rotating shear type stirrer equipped with a stationary ring (stator) that also serves as a baffle plate Stir.

  Furthermore, when using a media-type disperser, a filling rate of 60% to 80% of media (material is natural sand, glass peas, zirconia peas, etc.) with a diameter of about 0.7 mm to 3 mm in a cylindrical vessel. By attaching a plurality of discs to a rotating shaft installed in the center of the vessel and rotating it, a rapid swirling action is inserted into the media from the lower inlet of the vessel with a pump. Disperse and emulsify. When a colloid mill is used, a fixed disk or stationary ring is extremely close to a wear-resistant material disk or rotor that rotates at high speed (interval of 10 μm to 50 μm), and the high speed rotation is performed while maintaining the narrow gap. By supplying a fluid into the gap, a shearing force is applied to the limit to perform dispersion or emulsification. When using a high-pressure injection type emulsifying disperser, the processing liquid is press-fitted with a high-pressure plunger pump or the like, a special valve at the discharge part is adjusted and jetted at a high pressure (usually 10 MPa to 70 MPa), and an outlet fixing plate Is dispersed or emulsified by striking at a high speed of 100 m / sec to 300 m / sec.

  In addition, use an agitator such as an ultrasonic emulsification disperser that disperses or emulsifies by intensively generating ultrasonic energy, or a disperser / emulsifier that passes through a porous material such as a static mixer or glass / ceramics. You can also.

  By using one or a plurality of such dispersing / emulsifying machines in combination, the solvent mixture aqueous solution separated into two or more layers is mechanically dispersed or emulsified. Thus, by uniformly dispersing and emulsifying the solvent mixture aqueous solution separated into two or more layers by raising the temperature, using a dispersing and emulsifying machine, the particles of the organic layer produced by raising the temperature are uniformly distributed. Can be dispersed. And thereby, particles dispersed uniformly in the subsequent swelling treatment can be uniformly attached to the surface of the insulating resin material, and an extremely fine and uniform texture (unevenness) can be formed by the etching treatment. It becomes possible.

  Further, the aqueous solvent mixture solution separated into two or more layers to be dispersed or emulsified may further contain a surfactant as necessary. By containing a surfactant in the solvent mixture aqueous solution, dispersion or emulsification treatment of the solvent mixture aqueous solution separated into two or more layers can be facilitated. Further, it is possible to uniformly perform the dispersion or emulsification treatment, and the etching treatment for surface roughening in the subsequent steps can be made uniform.

  Specifically, the surfactant is not particularly limited, and any of nonionic surfactants, anionic surfactants, cationic surfactants and amphoteric surfactants may be used alone. Or 2 or more types can be used together.

  For example, nonionic surfactants include ethers such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, alkylallyl formaldehyde condensed polyoxyethylene ether, polyoxyethylene propylene block copolymer, polyoxyethylene polyoxypropylene alkyl ether, etc. Type surfactant, polyoxyethylene glycerin fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, ether ester type surfactant such as polyoxyethylene fatty acid alkanolamide sulfate, polyethylene glycol fatty acid ester, ethylene glycol Fatty acid ester, glycerin fatty acid ester, polyglycerin fatty acid ester, sorbitan fat Esters, propylene glycol fatty acid esters, ester type surfactants such as sucrose fatty acid esters, fatty acid alkanolamides, polyoxyethylene fatty acid amides, can be used nitrogen-containing type surfactants of polyoxyethylene alkylamine and the like.

  Examples of the anionic surfactant include lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid salts of carboxylic acids having 12 to 18 carbon atoms (sodium salts, potassium salts, etc.), and 12 to 18 carbon atoms. N-acylamino acid, N-acylamino acid salt, polyoxyethylene alkyl ether carboxylate, carboxylate such as acylated peptide having 12 to 18 carbon atoms, alkylsulfonate, alkylbenzenesulfonate, alkylnaphthalenesulfonate Salt, naphthalene sulfonate formalin polycondensate, sulfosuccinate, α-olefin sulfonate, sulfonate such as N-acyl sulfonate, sulfated oil, alkyl sulfate, alkyl ether sulfate, polyoxyethylene Sulfate, polyoxyethylene alkyl allyl ether sulfate Sulfate ester salts such as alkyl amide sulfates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl phenyl ether phosphates, can be used phosphoric acid ester salts such as alkyl phosphates and the like.

  Examples of amphoteric surfactants that can be used include carboxybetaine-type surfactants and aminocarboxylates, as well as imidazolium betaine and reticin. As lower alcohols, alcohols having about 1 to 4 carbon atoms such as methanol, ethanol, propanol, butanol, isopropanol, and isobutanol can be used.

  The amount of these surfactants added to the aqueous solvent mixture is preferably about 0.1 to 20 g / L, and more preferably 0.3 to 10 g / L. If the surfactant concentration is too low, dispersion and emulsification will not occur sufficiently. On the other hand, when the concentration is too high, the surface roughening proceeds excessively and the surface roughness increases.

  Using the swelling liquid adjusted as described above, the insulating resin material is subjected to a swelling treatment, and the insulating resin material subjected to the swelling treatment is subjected to a desmear treatment.

<Swelling treatment and etching treatment>
In the surface treatment method according to the present embodiment, for example, a via recess is formed by a well-known method such as a laser on a resin layer formed on one side or both sides of an insulating resin substrate, for example, and then a swelling treatment is performed. And the desmear process which roughens the surface of the insulating resin layer which comprises a printed wiring board by performing an etching process is performed. In particular, in the surface treatment method in the present embodiment, a swelling treatment is performed in which the surface of the resin layer is swollen by immersing the insulating resin substrate in the swelling liquid adjusted as described above.

  Here, the insulating resin material to which the surface treatment method according to the present embodiment can be applied is not particularly limited, and known materials can be used. Specifically, for example, epoxy resin (EP resin), polyimide resin (PI resin) which is a thermosetting resin film, bismaleimide-triazine resin (BT resin), polyphenylene ether resin (PPE resin), and the like, and Various resins such as liquid crystal polymer (LCP), polyether ether ketone resin (PEEK resin), polyether imide resin (PEI resin), polyether sulfone (PES resin), which are thermoplastic resin films, can be used. Or you may use the board | plate material etc. which consist of resin-resin composite material which impregnated thermosetting resin, such as EP resin, in three-dimensional network fluorine-type resin base materials, such as continuous porous PTFE. Further, a flexible film or the like may be used. As a particularly preferred resin, for example, when electroless plating treatment is performed in the subsequent process, there is no harmful eluate in the plating bath, and there is no interfacial peeling, and the circuit is formed by curing and forming a circuit. Thereafter, it is preferable that the resin has sufficient adhesion to the circuit surface and upper and lower surface layers and does not cause peeling or cracking in a test such as a cooling / heating cycle. In addition, for example, when a circuit pattern is formed by applying a conductive paste on an insulating resin by an inkjet method, generally a glass epoxy resin, a phenol resin, a glass polyimide resin, a glass bismaleimide resin, a glass polyphenylene oxide resin, It is preferable to select an insulating resin having good adhesion to a conductive paste such as an aramid epoxy resin or a liquid crystal polymer film. Further, as this insulating resin material, for example, a multi-layered structure may be used by bonding a plurality of substrates on which conductive layers are formed.

  In this embodiment, the above-described well-known insulating resin material is insulated by immersing it in a swelling solvent mixture aqueous solution (swelling liquid) produced by dispersing and emulsifying a solvent mixture aqueous solution separated into two or more layers. A swelling treatment is applied to the resin surface.

  In this swelling treatment, the treatment time is preferably about 30 seconds to about 15 minutes, more preferably about 1 to about 10 minutes, and is appropriately adjusted depending on the type of insulating resin material to be applied.

  As a swelling treatment method, the swelling treatment is performed by immersing the insulating resin in the adjusted swelling liquid for a predetermined time. This swelling treatment by immersion is efficient from the viewpoint that the swelling liquid can be sufficiently brought into contact with the insulating resin material, but is not limited thereto. For example, the swelling liquid may be sufficiently brought into contact by spraying the swelling liquid onto the insulating resin material.

  In addition, the swelling treatment is performed at a predetermined temperature or higher in order to separate the aqueous solvent mixture solution into two or more layers when adjusting the swelling liquid. Specifically, the swelling treatment is performed at a use temperature of about 40 to about 90 ° C., although it varies depending on the type of organic solvent constituting the solvent mixture aqueous solution and the mixing ratio of the organic solvent and water. In addition, as pH of swelling liquid, it can process in the wide range of pH1-14.

  Then, an etching process is performed on the insulating resin material that has been subjected to the swelling process as described above. This etching treatment can be performed by a well-known method using a well-known resin etching agent containing, for example, sodium permanganate, potassium permanganate, sodium chromate, potassium chromate and the like.

  Specifically, for example, when an etching agent containing sodium permanganate is used, the concentration is preferably about 5 to 600 g / L, more preferably about 10 to 60 g / L. When the concentration of the etching treatment liquid is too low, the etching effect is insufficient and an appropriate texture cannot be formed, and adhesion with the plating film cannot be obtained. Moreover, it is not preferable from the viewpoint that the plating film is liable to be skipped or swollen. On the other hand, if the concentration is too high, excessive etching is caused, and the surface roughness of the insulating resin material is increased, which makes it unsuitable for wiring that handles high-speed signals, high-density wiring, and the like. Further, it is not preferable from the viewpoint of work and economy.

  The temperature condition in the etching process is preferably about 50 to about 80 ° C., and the etching process is performed by immersing the insulating resin material in the etching solution for about 1 to about 10 minutes under this temperature condition. Note that the etching treatment is not limited to immersing the insulating resin material in the etching solution, and the insulating resin material may be treated by spraying the etching solution.

  As described above, by performing the etching process on the insulating resin subjected to the swelling process as described above, it is possible to form an extremely fine texture on the insulating resin and roughen the surface of the insulating resin.

  In this embodiment, in this way, prior to the etching treatment of the insulating resin, the swelling treatment is performed using the swelling liquid adjusted by dispersing and emulsifying the solvent mixture aqueous solution separated into two or more layers by increasing the temperature. Do. Specifically, the fine organic layer particles separated and generated by the temperature increase become finer by dispersion and emulsification and are uniformly dispersed in the aqueous solution, and the swelling treatment is performed using the swelling liquid in which the fine particles are dispersed. It is considered that the fine particles act to enable the surface of the insulating resin material to swell finely. And, by applying an etching treatment to the insulating resin material after the swelling treatment, it is possible to form extremely fine etching holes in the fine portions swollen by the swelling treatment on the surface of the insulating resin, and as a result, It is considered that an extremely fine texture can be formed on the surface of the insulating resin material.

  As described above, the surface treatment method according to the present embodiment is separated into two or more layers by raising the temperature rather than swelling the entire surface of the insulating resin material by using a single layer swelling liquid as in the prior art. Fine particles composed of an organic layer are formed using an aqueous solvent mixture solution, and a swelling treatment is performed on the surface of the insulating resin material using a swelling liquid in which the particles are uniformly dispersed. According to the surface treatment method according to the present embodiment, an extremely fine texture (unevenness) is formed on the resin surface by the swelling action and etching treatment by the fine particles, and the plating film formed on the insulating resin. Adhesion can be improved.

  When the surface of the resin substrate is roughened as described above, the processing residue generated on the surface of the resin substrate by the roughening treatment is dissolved and removed by reduction treatment. Specifically, a treatment liquid containing a reducing agent is used to form a resin substrate surface that is contained in an etching treatment liquid used in the roughening treatment, for example, a manganese oxide derived from sodium permanganate as a residue. The solution is removed by dissolution using a reduction reaction.

  Examples of the reduction treatment liquid include reducing agents composed of various amine compounds such as hydroxylamine sulfate, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, monoethanolamine, diethanolamine, ethylenediaminetetraacetic acid, and nitrilotriacetic acid. What was contained can be used. The concentration of the reducing agent is preferably about 1 to 200 g / L, and more preferably about 5 to 100 g / L. If the concentration of the reducing agent is too low, the effect of removing processing residues such as manganese oxide tends to be insufficient. On the other hand, if the concentration is too high, the pumping amount increases, which is economically undesirable.

  In addition, in the reduction treatment liquid containing a reducing agent such as the amine compound as described above, a pH adjuster such as sulfuric acid or sodium hydroxide, or a polysiloxane is used for the purpose of improving the surface wettability of the resin substrate. Surfactants such as nonionic surfactants such as oxyethylene alkyl ether, polyoxyethylene alkylphenol ether, and polyacetylene glycol can also be contained.

  As a treatment condition of the reduction treatment, a manganese oxide is obtained by immersing the insulating resin in a temperature condition of about 20 to about 90 ° C. for about 5 to about 30 minutes using a treatment liquid containing the reducing agent as described above. And the like are removed by dissolution. The pH of the reduction treatment solution can be used in a wide range of about pH 1-14.

  In addition, when an insulating resin containing a silica-based filler that forms an anchor in the insulating resin is used, an etching process that has an effect of etching the silica-based filler during or after the reduction process on the surface of the insulating resin Etching treatment may be performed using a liquid (hereinafter referred to as a filler etching treatment liquid). Specifically, the treatment can be performed using a filler etching solution containing a fluorine compound. Examples of the fluorine compound include hydrogen fluoride, sodium fluoride, borohydrofluoric acid, ammonium hydrogen fluoride, and fluorine. One kind or two or more kinds selected from sodium hydride, ammonium hexafluorosilicate, ammonium hexafluorophosphate and the like can be mixed and used in an arbitrary ratio. Thus, by processing using the filler etching processing liquid containing the fluorine compound, the surface of the insulating resin can be made finer and the adhesion between the insulating resin and the plating film can be further improved. Can be improved. This technical matter is described in Japanese Patent Application No. 2008-123457 filed earlier by the present inventors.

  In the surface treatment method according to the present embodiment, in forming the plating film constituting the circuit pattern, the above-described swelling treatment is performed on the insulating resin material, and the insulating resin material subjected to the swelling treatment is etched. By performing the above, an extremely fine texture can be formed on the surface. The extremely fine texture formed in this way does not cause disconnection or poor connection even when formed on a substrate such as a wiring that handles high-speed signals or a high-density wiring. The formed plating film and the insulating resin material can be firmly adhered.

  Below, although the metal-plating process performed on the insulating resin material which formed the texture as mentioned above is demonstrated, this metal-plating process is not limited to the following.

<Plating treatment>
When surface treatment is performed on the insulating resin material constituting the printed wiring board as described above, the treated insulating resin is then plated by a well-known method, and a plating film is formed on the insulating resin material. To form. In this plating process, a semi-additive method or a full additive method may be used.

  Below, the plating process by a full additive method is demonstrated concretely. In this description, an example of forming a copper plating film will be specifically described. However, the metal plating film is not limited to the copper plating film, and may be other metal plating film such as nickel. Moreover, as a plating method, not only a plating process by a full additive method but a plating film may be formed by electroplating using a semi-additive method.

  First, after a swelling process, an etching process, and a reduction process are performed on the insulating resin material constituting the printed wiring board, a cleaning process is performed by a known method to clean the resin board. In the cleaning treatment, for example, the resin substrate subjected to the surface treatment is immersed in a cleaning solution at 65 ° C. for 5 minutes to remove dust on the surface and to give the resin substrate water wettability. As the cleaning solution, an acidic solution or an alkaline solution may be used. By this cleaning process, the surface of the resin substrate can be cleaned and the adhesion of the plating film formed in the subsequent process can be further improved.

Once the resin substrate is cleaned, a catalyst is then applied to the surface of the resin substrate material that forms the circuit pattern. The catalyst used in the catalyst application is, for example, a catalyst solution containing divalent palladium ions (Pd ²⁺ ), such as palladium chloride (PdCl ₂ .2H ₂ O), stannous chloride (SnCl ₂ .2H ₂ O). ), A mixed solution composed of hydrochloric acid (HCl) or the like can be used. The concentration of the catalyst solution can be, for example, a concentration composition of Pd concentration of 100 to 300 mg / L, Sn concentration of 10 to 20 g / L, and HCl concentration of 150 to 250 mL / L. Then, the resin substrate is immersed in the catalyst solution for 1 to 3 minutes at a temperature of 30 to 40 ° C., for example, and first the Pd—Sn colloid is adsorbed on the surface of the resin substrate. The catalyst is activated by immersing it in an accelerator (accelerator) consisting of ˜100 mL / L sulfuric acid or hydrochloric acid. By this activation treatment, the complex compound tin is removed to form palladium-adsorbed particles, and finally, as a palladium catalyst, the deposition of copper by the subsequent electroless copper plating is promoted.

  Sodium hydroxide or ammonia solution may be used as an accelerator. In addition, when the catalyst is applied to the resin substrate, pretreatment using a conditioner solution or a pre-dip solution may be performed to further improve the adhesion between the resin substrate and the copper plating film. Furthermore, a pretreatment for improving the familiarity of the catalyst with the surface of the resin substrate may be performed. Naturally, the catalyst solution is not limited to the above.

  When the catalyst is applied to the resin substrate material as described above, a plating resist for appropriately forming a desired circuit pattern is formed next. That is, a resist pattern for masking other than the portion where the copper plating film constituting the circuit pattern is formed in the next step is formed. This resist pattern may be peeled off by an etching operation or the like after the end of the plating process, but may function as a solder resist without being peeled off. The plating resist can be formed using a known method.

  When the plating resist is formed, a copper plating film constituting a circuit pattern is then formed on the insulating resin material having an extremely fine texture formed on the surface by a plating process such as an electroless plating method.

  Specifically, in this plating treatment, for example, a plating bath using EDTA as a complexing agent can be used as the electroless copper plating bath. As an example of the composition of this electroless copper plating bath, an electroless copper plating bath containing copper sulfate (10 g / L) and EDTA (30 g / L) and adjusted to pH 12.5 with sodium hydroxide is used. be able to. Further, an electroless copper plating bath using Rochelle salt as a complexing agent may be used. Then, the copper plating film is formed by immersing the insulating resin substrate in the electroless copper plating bath for 30 to 600 minutes at a temperature of 60 to 80 ° C., for example. For example, when a via or the like for conduction with the lower layer is formed in the multilayer wiring board, it is preferable that the liquid is sufficiently stirred so that ions are sufficiently supplied to the via. As the stirring method, a method using air stirring, pump circulation, or the like can be applied.

  In depositing the copper plating film by the electroless plating method, after forming the plating resist, for example, by reducing the palladium adsorbed particles of the catalyst adhering to the surface of the resin substrate using 10% sulfuric acid and a reducer. The catalyst may be activated to promote the formation of a copper plating film on the resin substrate.

  In this plating process, a two-stage plating process may be applied in order to further improve the adhesion with the resin substrate material. That is, a primary plating process for forming a base plating film on a resin substrate material is performed, and a thick plating film having a thickness larger than the base plating film is formed on the formed base plating film by electroplating. Subsequent plating may be performed to form a circuit pattern. In particular, in the primary plating process, the internal stress in a direction different from the internal stress direction of the thick plating film formed in the secondary plating process, in other words, the thick plating film formed in the secondary plating process. The plating treatment may be performed using an electroless plating bath that forms an underlying plating film having a tensile internal stress that is an internal stress in a direction opposite to the internal stress.

  In addition, the plating bath used in the above-described plating treatment, its composition, treatment conditions, and the like are examples, and are not limited to these.

  Moreover, although the above-mentioned example is a specific example of the plating treatment using the electroless copper plating bath, the case where the electroless copper plating treatment is performed has been described, but the plating metal is not limited to copper, for example, Even if an electroless nickel plating bath is used, it can be satisfactorily applied. An example of the composition of the nickel plating bath includes, for example, nickel sulfate (20 g / L), sodium hypophosphite (15 g / L), and citrate (30 g / L), and is adjusted to pH 8-9. Plated baths can be used.

  In addition, as a plating method, a plating film may be formed not only by a plating process using a full additive method but also by an electroplating process using a semi-additive method.

  Further, even when a circuit pattern is formed by an ink jet method or the like, the surface treatment method according to the present embodiment can be similarly applied. That is, a specific example will be described. For example, Au, Ag, Cu, Pd, W, Ni, Ta, Bi, Pb, In, Sn, Zn, Ti, Al synthesized using a well-known technique. In addition to water, conductive metal particles composed of one or more metal fine particles selected from the above are dispersed in organic solvents such as polyethylene glycol monomethyl ether solvents, alcohol solvents, hydrocarbon solvents, etc. The conductive paste is uniformly dispersed to form a conductive paste, and the generated conductive paste droplets are applied onto an insulating resin substrate using an inkjet method or the like to form a circuit pattern. Next, an insulating layer is laminated on the substrate on which the circuit pattern formed by the conductive paste using the inkjet method or the like is arranged, and a trench is formed using a laser or the like. Expose the circuit pattern. Then, plating metal is deposited in the trench thus formed by, for example, electroless plating. As described above, even when a circuit pattern made of a conductive paste is formed using an inkjet method or the like, the surface treatment method according to the present embodiment is applied to the surface of the insulating resin in advance, so that the insulating resin material is excessively formed. The adhesiveness between the insulating resin and the plating film can be improved without roughening the surface. In addition, when the circuit pattern is formed by the inkjet method or the like in this way, it is possible to suppress the generation of voids, avoid wiring defects caused by the voids, and create a substrate with improved connection reliability. It becomes. In addition, variation in the height of the wiring can be suppressed, and a circuit board having a more uniform circuit surface and high connection reliability can be formed. Furthermore, when a circuit pattern is formed using an inkjet method or the like, the circuit pattern is misaligned or developed poorly compared to the case where a circuit pattern is formed by electroplating or electroless plating using a plating resist. The desired fine circuit pattern can be drawn more accurately. This technical matter is described in Japanese Patent Application No. 2007-285363 filed earlier by the present inventors.

  As described above, in the surface treatment method according to the present embodiment, the solvent mixture aqueous solution containing at least one organic solvent is separated into two or more layers, and the solvent mixture aqueous solution separated into two or more layers is dispersed or dispersed. It emulsifies to make a swelling solvent mixture aqueous solution, and the swelling treatment is performed by immersing the insulating resin in the swelling solvent mixture aqueous solution.

  That is, a solvent mixture aqueous solution containing at least one organic solvent is separated into two or more layers by raising the temperature to a predetermined temperature or higher, and the separated solvent mixture aqueous solution is mechanically dispersed and emulsified to swell the solvent. An aqueous solution of the mixture is generated and used as a swelling liquid.

  And the etching process is performed with respect to the insulating resin material swollen using this swelling liquid, and the surface of the insulating resin material is roughened.

  In this way, the solvent mixture aqueous solution separated into two or more layers by raising the temperature is dispersed or emulsified, and the swelling treatment is performed by swelling the insulating resin material using the swelling solvent mixture aqueous solution (swelling liquid). By performing an etching process on the treated insulating resin material, the fine particles composed of the organic layer generated by the temperature increase become uniform, and the fine particles act on the resin surface very finely and uniformly. Since it swells, an etching hole is formed only in the swollen portion, and it is considered that an extremely fine texture can be formed on the surface of the insulating resin material. And thereby, it is possible to form a strong adhesive force between the insulating resin material constituting the printed wiring board and the plating film with uniform and extremely fine unevenness without greatly roughening the surface of the insulating resin material. In addition, a printed circuit board suitable for wiring that handles high-speed signals can be formed.

  Note that the present invention is not limited to the above-described embodiment, and any design change or the like without departing from the gist of the present invention is included in the present invention.

  Further, the present invention is not only applied to the method of manufacturing a wiring board according to the above-described embodiment and the manufacturing of a high-density multilayer wiring board by a build-up method. For example, a wafer level CSP (Chip Siz Epoxy Package or Chip) is used. The present invention is also applied to a manufacturing process of a multilayer wiring layer in Scale Epoxy Package) or TCP (Tape Carrier Package).

  Hereinafter, specific examples of the present invention will be described. Note that the scope of the present invention is not limited to any of the following examples.

Example 1
First, a solvent mixture aqueous solution containing the following organic solvent was heated to 80 ° C., and the solution separated into two layers was dispersed and emulsified with a propeller stirrer to produce a swelling liquid.
Diethylene glycol monobutyl ether: 200 g / L
Diethylene glycol diethyl ether: 250 g / L

  Next, using a substrate on which a general insulating resin (ABF-GX13 manufactured by Ajinomoto Fine Techno Co., Ltd.) was laminated, the substrate was immersed in a swelling solution for 1 minute to perform a swelling treatment.

  Thereafter, the substrate immersed in the swelling solution is etched with a resin etching solution (DES-502, manufactured by Uemura Kogyo Co., Ltd.), and then subjected to a reduction treatment with a reducing solution (DEN-503H, manufactured by Uemura Kogyo Co., Ltd.). Roughness (Ra) and the average interval of unevenness (RSm) were measured.

  Subsequently, a catalyst is applied to the substrate by a catalyst application process (through-cup process: cleaner conditioner ACL-009, pre-dip PED-104, catalyst AT-105, accelerator AL-106 (all manufactured by Uemura Kogyo Co., Ltd.)). Then, electroless copper plating treatment was performed with an electroless copper plating solution (PEA manufactured by Uemura Kogyo Co., Ltd.) to form a 0.5 μm plating film.

  Further, using an electrolytic copper plating solution (ETN manufactured by Uemura Kogyo Co., Ltd.), an electrolytic copper plating treatment was performed to form a copper plating film having a thickness of 30 μm, and the peel strength of the copper plating film was measured.

(Example 2)
Unlike Example 1, the solvent mixture composition containing the following organic solvent and surfactant and a water-soluble metal oxide was heated to 80 ° C., and the solution separated into two layers was dispersed with a propeller stirrer -The emulsified swelling liquid was produced | generated.
Diethylene glycol monobutyl ether: 400 g / L
Diethylene glycol diethyl ether: 100 g / L
ADEKA COAL W-287 (Asahi Denka Kogyo Co., Ltd. polycarboxylic acid type anionic surfactant): 0.5 g / L
Sodium hydroxide: 5g / L

  Subsequent treatments were performed in the same manner as in Example 1 except that the solvent mixture aqueous solution having the above composition was used. That is, using a substrate laminated with a general insulating resin (ABF-GX13 manufactured by Ajinomoto Fine-Techno Co., Ltd.), immersing it in the swelling solution that produced this substrate for 1 minute and then performing a swelling treatment, followed by resin etching and reduction treatment Then, the surface roughness (Ra) of the substrate and the average interval (RSm) of the irregularities were measured. Then, in the same manner as in Example 1, pretreatment, electroless copper plating, and electrolytic copper plating were performed, and the peel strength of the copper plating film was measured.

(Comparative Example 1)
Using the following organic solvent, the operating temperature was set to 80 ° C. to obtain a swelling liquid.
Diethylene glycol monobutyl ether: 400 g / L
In addition, the said organic solvent was single layer aqueous solution in the operating temperature of 80 degreeC.

  Except for using the swelling liquid composed of the above organic solvent and swelling the substrate with a general insulating resin (ABF-GX13 manufactured by Ajinomoto Fine Techno Co., Ltd.) laminated for 5 minutes. The same treatment as in Example 1 was performed. That is, after the swelling treatment, resin etching and reduction treatment are performed, and the surface roughness (Ra) and average interval (RSm) of the unevenness are measured, followed by pretreatment, electroless copper plating, electrolytic copper Plating was performed and the peel strength of the copper plating film was measured.

(Comparative Example 2)
An aqueous solution comprising the following organic solvent and water-soluble metal oxide was used, and the use temperature was set to 60 ° C. to obtain a swelling liquid.
n-methyl-2-pyrrolidone: 300 g / L
Ethylene glycol butyl ether: 200 g / L
Sodium hydroxide: 3g / L
The aqueous solution having the above composition was a single layer aqueous solution at a use temperature of 60 ° C.

  Other than performing swelling treatment by immersing a substrate with a general insulating resin (ABF-GX13 manufactured by Ajinomoto Fine Techno Co., Ltd.) laminated for 10 minutes using a swelling liquid composed of the above organic solvent, etc. Were processed in the same manner as in Example 1. That is, after the swelling treatment, resin etching and reduction treatment are performed, and the surface roughness (Ra) and average interval (RSm) of the unevenness are measured, followed by pretreatment, electroless copper plating, electrolytic copper Plating was performed and the peel strength of the copper plating film was measured.

(Comparative Example 3)
Using the following organic solvent, the operating temperature was set to 70 ° C. to obtain a swelling liquid.
n-methyl-2-pyrrolidone: 500 g / L
The organic solvent was a single layer aqueous solution at a use temperature of 70 ° C.

  Except for using a swelling liquid composed of the above-mentioned organic solvent and swelling a substrate on which a general insulating resin (ABF-GX13 manufactured by Ajinomoto Fine Techno Co., Ltd.) was laminated by immersing the resulting swelling liquid for 15 minutes. The same treatment as in Example 1 was performed. That is, after the swelling treatment, resin etching and reduction treatment are performed, and the surface roughness (Ra) and average interval (RSm) of the unevenness are measured, followed by pretreatment, electroless copper plating, electrolytic copper Plating was performed and the peel strength of the copper plating film was measured.

(Comparative Example 4)
Using a 100% solvent containing the following organic solvent, the operating temperature was set to 70 ° C. to obtain a swelling liquid.
n-methyl-2-pyrrolidone: 700 g / L
Ethylene glycol butyl ether: 300 g / L
The aqueous solution was a single layer aqueous solution at a use temperature of 70 ° C.

  Other than performing the swelling treatment by immersing the substrate in which a general insulating resin (ABF-GX13 manufactured by Ajinomoto Fine Techno Co., Ltd.) is laminated for 5 minutes using the swelling liquid composed of the above organic solvent, etc. Were processed in the same manner as in Example 1. That is, after the swelling treatment, resin etching and reduction treatment are performed, and the surface roughness (Ra) and average interval (RSm) of the unevenness are measured, followed by pretreatment, electroless copper plating, electrolytic copper Plating was performed and the peel strength of the copper plating film was measured.

  In the above examples and comparative examples, the surface roughness (Ra) of the resin substrate and the average interval (RSm) of the unevenness were measured at 3 points for each sample using a laser microscope (VK-8550 manufactured by Keyence Corporation). The average value was measured. The peel strength of the plating film was measured using an autograph (AGS-100D manufactured by Shimadzu Corporation). The measurement results of the examples and comparative examples are shown in Table 1 below.

  As shown in Table 1, by using an organic solvent that separates from water by increasing the temperature, a solvent mixture aqueous solution separated into a plurality of layers is prepared, and the solvent mixture aqueous solution is mechanically dispersed and emulsified. In Example 1 in which the swelling treatment was performed using the generated swelling liquid, the surface roughness (Ra) was 0.25 μm and the surface roughness was as extremely small as 650 N / m. Moreover, while using the organic solvent similar to Example 1, the solvent mixture aqueous solution isolate | separated into multiple layers using sodium hydroxide which is a water-soluble metal hydroxide is adjusted, surfactant is contained and it is mechanically included. Even in Example 2 in which the swelling treatment was performed using the swelling liquid generated by dispersing and emulsifying, it was possible to realize a peeling strength as large as 670 N / m with an extremely small surface roughness of about Ra 0.37 μm. did it. Thus, in Examples 1 and 2, it was possible to achieve a high peel strength without increasing the roughness of the substrate surface.

  On the other hand, in Comparative Example 1 where a single organic solvent was used and the swelling treatment was performed using a single layer aqueous solution that did not separate from water even when the temperature was raised, the surface roughness was Ra 0.33 μm. Was small, but the peel strength was very weak at 330 N / m, and the adhesion between the resin and the copper plating film was small. Further, in Comparative Example 2, as in Examples 1 and 2 described above, the treatment was performed using a mixture aqueous solution containing a plurality of organic solvents and further containing a water-soluble metal hydroxide. Only a single layer was formed without separation, and Ra 0.44 μm and the surface roughness were larger than those in Examples 1 and 2, and the peel strength was very weak at 390 N / m.

  In Comparative Examples 1 and 2, although the surface roughness (Ra) of the insulating resin material formed by performing desmear treatment or the like was substantially the same as that of Examples 1 and 2, the peel strength was Made a big difference as mentioned above. As can be clearly seen from the value of the average interval (RSm) of the irregularities in Table 1, in Examples 1 and 2, the surface roughness could be reduced and the irregularities were fine on the surface. Therefore, it is considered that even if the surface roughness was reduced, a strong peeling strength of 650 N / m or more could be realized. On the other hand, in Comparative Examples 1 and 2, although the surface roughness could be reduced, the irregularities formed on the surface were sparse, and the average interval between the irregularities was 5.89 μm in Comparative Example 1, Comparative Example 2 In this case, the average interval was 6.28 μm, which was almost twice that of the example.

  As described above, in Examples 1 and 2, the surface roughness could be reduced, and the intervals on the insulating resin material surface of the unevenness having a small roughness could be reduced. That is, in Examples 1 and 2, it is possible to form an extremely fine texture (unevenness) having a small surface roughness and a small average interval of unevenness on the surface of the insulating resin. A strong peel strength was achieved. On the other hand, in Comparative Examples 1 and 2, although the surface roughness could be reduced, since the swelling treatment was performed using a single layer aqueous solution, the swelling liquid spread over a wide area on the entire surface of the insulating resin material. As a result, it is considered that the average interval between the irregularities formed on the resin surface is large and the texture becomes sparse, and sufficient peel strength cannot be realized.

  Moreover, when it sees also about Comparative Examples 3 and 4, it is the comparison which performed the swelling process using the aqueous solution which was a single layer without separating from water even if it heated up to 70 degreeC using the single organic solvent. In Example 3, the peel strength between the plated substrate and the copper plating was as large as 690 N / m, but the surface roughness on the insulating resin substrate was as extremely large as Ra 0.68 μm. Further, in Comparative Example 4 in which the swelling treatment was performed by using a plurality of organic solvents and raising the temperature to 70 ° C., the peel strength after the plating treatment was as large as 760 N / m, which was larger than that in Comparative Example 3. However, the surface roughness formed on the insulating resin substrate was very rough with Ra 0.86 μm. In addition, the solvent mixture aqueous solution used in this Comparative Example 4 was not separated, and only a single layer was formed.

  Moreover, in these comparative examples 3 and 4, as can be clearly seen from Table 1, an extremely large average interval (RSm) value of the unevenness as compared with the examples 1 and 2 was shown. That is, the surface of the insulating resin material has a large surface roughness in Comparative Examples 3 and 4 compared to Examples 1 and 2 in which the surface roughness is small, the average interval between the irregularities is small, and extremely fine irregularities are formed on the surface. It can be seen that the formed irregularities were sparsely formed on the entire surface.

  The results of Comparative Examples 1 to 4 are considered to depend on the properties of the swelling liquid used in the swelling treatment. That is, for example, diethylene glycol monobutyl ether, which is an organic solvent used in Comparative Example 1, is frequently used as a swelling agent. However, since this organic solvent is a water-soluble solvent, it cannot be separated from water even when the temperature is raised. There is no single layer. When the swelling treatment is performed using this swelling liquid, since it is a single layer, it acts on the entire surface of the insulating resin material over a wide range. Therefore, the surface of the insulating resin material on which the swelling liquid acts by the subsequent etching treatment It is considered that the entire surface was etched, and as a result, the surface roughness (Ra) was increased and the unevenness having a large average interval was formed.

  As can be clearly seen from the above results, an aqueous solvent mixture solution containing an amphiphilic organic solvent having a property of separating from water at a predetermined temperature or higher by increasing the temperature and separated into two or more layers at the predetermined temperature or higher. Then, the aqueous solution is mechanically dispersed and emulsified as a swelling liquid, and the swelling treatment is performed on the insulating resin base material using the swelling liquid, and then the etching process is performed on the surface of the insulating resin material. Thus, it is possible to form an extremely fine texture, and even with a small surface roughness, it is possible to form a strong adhesion between the insulating resin substrate after plating and the plating film.

  And by using such a substrate on which a very fine texture is formed on the surface of the insulating resin material and a strong adhesive force is formed between the plating film, wiring for handling high-speed signals and high density A printed circuit board suitable for wiring or the like can be manufactured.

Claims (5)

A solvent mixture aqueous solution containing at least one organic solvent is separated into two or more layers by raising the temperature to a predetermined temperature or more, and the solvent mixture aqueous solution separated into two or more layers is dispersed or emulsified to obtain a swelling solvent mixture aqueous solution. A swelling treatment method in which an insulating resin is immersed in the swelling solvent mixture aqueous solution to swell. The organic solvent is ethylene glycol, ethylene glycol monoalkyl ether, ethylene glycol dialkyl ether, diethylene glycol, diethylene glycol monoalkyl ether, diethylene glycol dialkyl ether, triethylene glycol, triethylene glycol monoalkyl ether, triethylene glycol dialkyl ether, propylene glycol, propylene glycol monoalkyl ether, propylene glycol dialkyl ether, dipropylene glycol, dipropylene glycol monoalkyl ethers, dipropylene glycol dialkyl ethers, glycol monoalkyl ethers, polyethylene glycol, polyethylene glycol monoalkyl ether, polyethylene glycol di Ruki ethers, pyrrolidone, pyrrolidine, swelling treatment method according to claim 1, wherein at least one selected from the group consisting of a lactone. The swelling treatment method according to claim 1 or 2 , wherein the aqueous solvent mixture solution contains a water-soluble metal hydroxide or a water-soluble metal salt. The swelling method according to any one of claims 1 to 3 , wherein a surfactant is contained in the aqueous solvent mixture solution to disperse or emulsify. A surface treatment method for an insulating resin of a printed wiring board,
A solvent mixture aqueous solution containing at least one organic solvent is separated into two or more layers by raising the temperature to a predetermined temperature or more, and the solvent mixture aqueous solution separated into two or more layers is dispersed or emulsified to obtain a swelling solvent mixture aqueous solution. A swelling treatment step in which an insulating resin is immersed in the swelling solvent mixture aqueous solution to swell,
An etching treatment step of etching the insulating resin swollen in the swelling treatment step.