JP2019039027A - Copper micro etching agent and method for producing wiring board - Google Patents

Abstract

To provide a micro etching agent that can form a roughened shape having excellent adhesion to resin or the like, on a copper surface, even with a small amount of etching, and a method for producing a wiring board using the micro etching agent.SOLUTION: A micro etching agent contains a water-soluble cationic polymer having an inorganic acid, a cupric ion, a halide ion, and a quaternary ammonium group in a side chain, with a weight average molecular weight of 1000 or more. In the micro etching agent, a molar concentration of halide ions is 5-100 times higher than a molar concentration of cupric ions.SELECTED DRAWING: None

Description

  The present invention relates to a copper microetching agent and a method of manufacturing a wiring board.

  In the production of a printed wiring board, in order to improve the adhesion between the copper surface and a resin material such as a solder resist, the copper surface is roughened with a microetching agent (roughening agent). As micro-etching agents for copper or copper alloys, organic acid-based micro-etching agents (for example, Patent Document 1) and inorganic acid-based micro-etching agents (for example, Patent Document 2) are known. These microetching agents contain an acid and an oxidizing agent, and further, halogen, polymer, ammonium salt, amines, surfactants, and the like are added for the purpose of adjusting the roughening shape and etching rate.

WO2014 / 0117115 pamphlet WO2007 / 024312 pamphlet

  In roughening with a microetching agent, the roughening proceeds as the etching amount increases, so that the adhesion with a resin or the like tends to be improved. On the other hand, when the copper wiring is roughened with a micro-etching agent, line thinning occurs with the progress of etching, which may cause problems such as high resistance and disconnection. As the wiring pitch becomes narrower (fine wiring), the influence of thinning of the wiring becomes more prominent. Therefore, a microetching agent capable of realizing high adhesion with a low etching amount is required.

  The organic acid microetching agent of Patent Document 1 can form a roughened shape having excellent adhesion to a solder resist or the like on the copper surface even when the etching amount is 1 μm or less. However, organic acid-based microetching agents contain organic acids and ammonium salts at high concentrations, and therefore require dedicated drainage / waste liquid treatment facilities, and are not highly versatile.

  Patent Document 2 describes that a roughened shape excellent in adhesion to a solder resist or the like can be formed on a copper surface with an etching amount of about 1.5 μm by using a hydrochloric acid-based microetching agent containing polyethyleneimine. An inorganic acid-based etching agent has an advantage that drainage and waste liquid treatment are easier than an organic acid-based etching agent. However, in order to ensure adhesion with a resin using an inorganic acid-based etching agent, it is necessary to increase the etching amount as compared with the case where an organic acid-based etching agent is used.

  In view of the above, an object of the present invention is to provide an inorganic acid-based microetching agent capable of forming a roughened shape having excellent adhesion to a resin or the like on a copper surface even with a low etching amount.

  The present invention relates to a copper microetching agent used for copper surface roughening. In addition, "copper" in this specification includes copper and a copper alloy. The “copper layer” also includes a copper wiring pattern layer. The microetching agent of the present invention is an inorganic acid-based microetching agent containing an inorganic acid, cupric ions, halide ions, and a cationic polymer. The cationic polymer is a water-soluble polymer having a side chain containing a quaternary ammonium group and having a weight average molecular weight of 1000 or more. The molar concentration of halide ions in the microetching agent is 5 to 100 times the molar concentration of cupric ions. The pH of the microetching agent is preferably 2 or less. The weight concentration of cupric ions is preferably 50 to 2000 times the weight concentration of the polymer.

  Furthermore, this invention relates to the manufacturing method of the wiring board which manufactures the wiring board containing a copper layer. The manufacturing method of a wiring board has the process (roughening process process) which makes the said microetching agent contact the copper surface and roughens. In the roughening treatment step, a replenisher may be added to the microetching agent in order to keep the composition of the microetching agent within a predetermined range. The etching amount in the roughening treatment is, for example, 1 μm or less. The “etching amount” refers to an average etching amount (dissolution amount) in the depth direction, and is a value calculated from the weight and specific gravity of copper dissolved by the microetching agent and the front projected area of the copper surface. The same applies to the following “etching amount”.

  According to the present invention, it is possible to form a roughened shape on the copper surface with excellent adhesion to a resin or the like even with a low etching amount.

The scanning electron micrograph of the copper surface processed with the solution of the mixing | blending 1. The scanning electron micrograph of the copper surface processed with the solution of the mixing | blending 2. Scanning electron micrograph of the copper surface treated with the solution of Formulation 3. The scanning electron micrograph of the copper surface processed with the solution of the mixing | blending 8. The scanning electron micrograph of the copper surface processed with the solution of the mixing | blending 9. A scanning electron micrograph of a copper surface treated with a solution of Formulation 10. Scanning electron micrograph of the copper surface treated with the solution of Formulation 11. Scanning electron micrograph of the copper surface treated with the solution of Formulation 12. Scanning electron micrograph of the copper surface treated with the solution of Formulation 13. A scanning electron micrograph of a copper surface treated with a solution of Formulation 18. Scanning electron micrograph of a copper surface treated with a solution of Formulation 19. A scanning electron micrograph of a copper surface treated with a solution of Formulation 20. A scanning electron micrograph of the copper surface treated with the solution of Formulation 21. A scanning electron micrograph of the copper surface treated with the solution of Formulation 22. A scanning electron micrograph of the copper surface treated with the solution of Formulation 23. Scanning electron micrograph of the copper surface treated with the solution of Formulation 24. Scanning electron micrograph of a copper surface treated with a solution of Formula 25. A scanning electron micrograph of a copper surface treated with a solution of Formulation 26. A scanning electron micrograph of a copper surface treated with a solution of Formulation 27. The surface photograph of the test piece of the evaluation result A in the solder heat resistance test. The surface photograph of the test piece of evaluation result B in the solder heat resistance test. A surface photograph of a test piece of evaluation result X in a solder heat resistance test.

[Composition of micro-etching agent]
The microetching agent of the present invention is used for surface roughening of copper. The microetching agent is an acidic aqueous solution containing an inorganic acid, cupric ions, halide ions and a polymer. Hereinafter, each component contained in the microetching agent of the present invention will be described.

<Cupric ion>
Cupric ion acts as an oxidizing agent for oxidizing copper. As a cupric ion source to be blended with the microetching agent, copper halides such as cupric chloride and cupric bromide; inorganic acid salts such as cupric sulfate and cupric nitrate; cupric formate, Organic acid salts such as cupric acetate; cupric hydroxide; cupric oxide and the like. Since cupric halide produces cupric ions and halide ions in an aqueous solution, it can be used as having both functions of a halide ion source and a cupric ion source. As the cupric ion source, copper halide, cupric oxide or inorganic acid salt is preferable. Note that the composition in the case where cupric oxide coexists with hydrohalic acid such as hydrochloric acid is equivalent to the case where copper halide is dissolved. The cupric oxide is preferably one that dissolves quickly and easily in an acid, and the readily soluble cupric oxide used in “copper plating solution using an insoluble anode” or the like is desirable.

  The cupric ion concentration of the microetching agent is preferably 0.0005 to 0.5 mol / L, more preferably 0.001 to 0.3 mol / L, and 0.005 to 0.2 mol / L or less. Further preferred. By adjusting the cupric ion concentration, the etching rate is in an appropriate range, so that the etching amount can be easily controlled.

<Inorganic acid>
The acid has a function of dissolving copper oxidized by cupric ions in an aqueous solution and also has a pH adjusting function. When the cupric ion concentration in the solution is increased by the progress of etching, the pH of the microetching agent is preferably 2 or less from the viewpoint of suppressing the precipitation of copper hydroxide and the like and improving the stability of the solution. .5 or less is more preferable, and 1 or less is more preferable.

  From the viewpoint of keeping the pH of the microetching agent low, an inorganic acid is used as the acid. Inorganic acids are less likely to coordinate to cupric ions in aqueous solutions than organic acids. Therefore, by using an inorganic acid, it is possible to appropriately maintain the action of the cupric ion as an oxidizing agent in the microetching agent. The inorganic acid is preferably a hydrohalic acid such as hydrochloric acid or hydrobromic acid, or a strong acid such as sulfuric acid or nitric acid. Hydrohalic acid can be used as having the action of both a halide ion source and an acid. Therefore, the microetching agent of the present invention preferably contains hydrohalic acid as an inorganic acid. Of the hydrohalic acids, hydrochloric acid (aqueous hydrogen chloride solution) is preferred. Two or more acids may be used in combination, and a small amount of an organic acid may be used in addition to the inorganic acid. The acid concentration of the microetching agent is preferably adjusted so that the pH is in the above range.

<Halide ion>
Halide ions assist the dissolution of copper and have a function of forming a copper layer surface with excellent adhesion. Examples of halide ions include chloride ions and bromide ions. Among these, chloride ions are preferable from the viewpoint of uniformly forming a roughened shape having excellent adhesion. The microetching agent may contain two or more halide ions.

  Halide ion sources to be blended with the microetching agent include hydrohalic acids such as hydrochloric acid and hydrobromic acid; sodium chloride, calcium chloride, potassium chloride, ammonium chloride, potassium bromide, sodium bromide, copper chloride, odor Examples thereof include metal salts such as copper chloride, zinc chloride, iron chloride and tin bromide. Two or more halide ion sources may be used in combination. As described above, hydrohalic acid has the action of both a halide ion source and an acid, and copper halide has the action of both a halide ion source and a cupric ion source.

  From the viewpoint of promoting the formation of a roughened shape on the copper surface, the concentration of halide ions in the microetching agent is preferably 0.005 to 10 mol / L, more preferably 0.05 to 5 mol / L, 0.1-3 mol / L is more preferable. By setting the halide ion concentration within the above range, dissolution of cuprous ions generated by oxidation of copper into the solution is promoted, and the formation of smut on the copper layer surface tends to be suppressed. As will be described later, the microetching agent contains an excess of halide ions relative to cupric ions. Therefore, the appropriate range of halide ion concentration is set according to the cupric ion concentration.

<Polymer>
The microetching agent of the present invention contains a water-soluble polymer having a quaternary ammonium group in the side chain and having a weight average molecular weight of 1000 or more. A polymer has the effect | action which forms the rough shape excellent in adhesiveness with a halide ion. In the microetching agent, cuprous ions and halide ions and a polymer having a quaternary ammonium group in the side chain coexist, whereby fine irregularities can be uniformly formed on the copper surface. From the viewpoint of forming a uniform roughened shape, the weight average molecular weight of the polymer is preferably 2000 or more, and more preferably 3000 or more. From the viewpoint of water solubility, the polymer weight average molecular weight is preferably 5 million or less, and more preferably 2 million or less. The weight average molecular weight is a value obtained in terms of polyethylene glycol by gel permeation chromatograph (GPC) analysis.

  Examples of the polymer having a quaternary ammonium group in the side chain include a polymer having a repeating unit represented by the following formula (I).

In formula (I), R ^{1 to} R ³ are each independently a chain or cyclic hydrocarbon group which may have a substituent, and two or more of R ^{1 to} R ³ are bonded to each other. Thus, a ring structure may be formed. R ⁴ is a hydrogen atom or a methyl group, X ¹ is a single bond or a divalent linking group, and Y ⁻ is a counter anion.

  Specific examples of the polymer having a repeating unit represented by the formula (I) include a quaternary ammonium salt type styrene polymer, a quaternary ammonium salt type aminoalkyl (meth) acrylate polymer, and the like.

  The polymer having a quaternary ammonium group in the side chain includes a repeating unit in which the main chain carbon atom and the side chain quaternary ammonium group form a cyclic structure, as represented by the following formula (II). You may have.

In the above formula (II), R ⁵ and R ⁶ are chain or cyclic hydrocarbon groups which may have a substituent, and R ⁵ and R ⁶ are bonded to each other to form a cyclic structure. Also good. m is an integer of 0-2. X ² and X ³ are each independently a single bond or a divalent linking group. Specific examples of the polymer having a repeating unit of the formula (II) include a quaternary ammonium salt type diallylamine polymer obtained by polymerization of a diallyldialkylammonium salt represented by the formula (IIa).

In the formula (IIa), R ⁷ and R ⁸ are each independently a hydrogen atom or a chain or cyclic hydrocarbon group which may have a substituent, and preferably a hydrogen atom.

The side chain quaternary ammonium group may have a double bond between a nitrogen atom and a carbon atom. The counter anion Z ⁻ of the quaternary ammonium salt includes Cl ⁻ , Br ⁻ , I ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , CH ₃ COO ⁻ , PF ₆ ⁻ , HSO ₄ ⁻ , C ₂ H ₅ SO ₄ ^−. Is mentioned. When X ^{1 to} X ⁷ are divalent linking groups, specific examples thereof include a methylene group, an alkylene group having 2 to 10 carbon atoms, an arylene group, a —CONH—R— group, a —COO—R— group ( However, R is a single bond, a methylene group, an alkylene group having 2 to 10 carbon atoms, or an ether group (alkyloxyalkyl group) having 2 to 10 carbon atoms).

  The polymer containing a quaternary ammonium group in the side chain may be a copolymer. When the polymer is a copolymer, the copolymer may include a repeating unit containing a quaternary ammonium group and a repeating unit not containing a quaternary ammonium group. The arrangement of the repeating units in the copolymer is not particularly limited, and any of an alternating copolymer, a block copolymer, and a random copolymer may be used. When the copolymer is a block copolymer or a random copolymer, the ratio of the repeating unit containing a quaternary ammonium group to the monomer unit of the whole polymer is preferably 20 mol% or more, more preferably 30 mol% or more. 40 mol% or more is more preferable. As a repeating unit not containing a quaternary ammonium group, a structure derived from (meth) acrylic acid, alkyl (meth) acrylate, aminoalkyl (meth) acrylate, (meth) acrylamide, styrene derivative, sulfur dioxide, etc. Can be mentioned.

  In the above-mentioned Patent Document 2, low molecular weight polyethyleneimine is used as the polymer of the inorganic acid microetching agent. A modified shape cannot be formed. Patent Document 1 described above describes an example in which high molecular weight polyethyleneimine is used as the polymer of the organic acid microetching agent. Since the microetching agent of the present invention mainly uses an inorganic acid as the acid, the pH is low. Polyethyleneimine having a cationic group in the main chain is unstable under strong acidity, and it is difficult to form a fine roughened shape. On the other hand, a cationic polymer containing a quaternary ammonium group in the side chain is stable even under strong acidity of pH 1 or less, and contributes to the formation of a fine roughened shape.

  The concentration of the polymer in the microetching agent is preferably 0.0002 to 0.2 g / L, more preferably 0.001 to 0.04 g / L, from the viewpoint of forming a copper layer surface having excellent adhesion. 0.004 to 0.02 g / L is more preferable. As will be described later, an appropriate range of the polymer concentration in the microetching agent is set according to the cupric ion concentration.

<Ratio of each component>
One feature of the microetching agent of the present invention is that it contains an excess amount of halide ions relative to cupric ions. The halide ion concentration (molar concentration) of the microetching agent is preferably at least 5 times the cupric ion concentration, more preferably at least 7 times, and even more preferably at least 10 times. When the microetching agent contains an excess amount of halide ions relative to cupric ions, a roughened shape having excellent adhesion to a resin or the like can be formed on the copper surface even with a low etching amount. From the viewpoint of forming a uniform roughened shape, the halide ion concentration is preferably 100 times or less, more preferably 70 times or less, and even more preferably 50 times or less the cupric ion concentration.

  In an etching agent containing halide ions and cupric ions as oxidizing agents, metallic copper is oxidized and cupric ions are generated by reducing cupric ions. Since cuprous halides such as copper (I) chloride have low solubility, insoluble smut is deposited on the copper surface. On the other hand, since one cuprous ion forms a soluble complex with four halide ions, if there is an excess of halogen, the cuprous halide rapidly re-dissolves. That is, when excessive halogen is present, deposition of smut on the copper surface is suppressed, so that each component constituting the microetching agent can easily come into contact with the metal copper surface. In such an environment, it is considered that the above-mentioned cationic polymer is easily manifested, and even with a low etching amount, fine irregularities excellent in adhesion to the resin are likely to be formed.

  From the viewpoint of enhancing the surface shape forming action by the cationic polymer, the weight concentration of the cupric ion in the etching agent is preferably 50 to 2000 times, more preferably 100 to 1500 times the weight concentration of the cationic polymer. 1000 times is more preferable.

<Other additives>
The microetching agent of the present invention can be prepared by dissolving each of the above components in ion exchange water or the like. The microetching agent may contain components other than those described above. For example, a nonionic surfactant may be added for the purpose of uniforming the roughening. The nonionic surfactant also acts as an antifoaming agent. In addition, you may add various additives as needed. When these additives are used, the concentration of the additive in the microetching agent is preferably about 0.0001 to 20% by weight.

[Use of micro-etching agent]
The above microetching agent can be widely used for roughening the copper layer surface. Fine irregularities are uniformly formed on the treated copper surface, and the adhesiveness with a resin such as a prepreg, a plating resist, an etching resist, a solder resist, an electrodeposition resist, or a coverlay is good. Moreover, since it is excellent also in the soldering property of the roughened copper surface, it is especially useful for manufacture of various wiring boards including those for pin grid arrays (PGA) and ball grid arrays (BGA). It is also useful for surface treatment of lead frames.

  In particular, since the microetching agent of the present invention can form a surface with a low etching amount and excellent adhesion, printed wiring boards that require fine copper wiring, fan-out wafer level packages (FOWLP), LSIs This is useful for improving the adhesion of the re-wiring copper layer, etc., and contributes to increasing the resistance of the copper wiring and suppressing disconnection.

[Method of manufacturing a wiring board]
In the production of the wiring board, the copper surface is roughened by bringing the above-mentioned microetching agent into contact with the copper surface. When manufacturing a wiring board including a plurality of copper layers, only one of the plurality of copper layers may be treated with the microetching agent, and two or more copper layers may be treated with the microetching agent. May be.

  In the roughening treatment, the method of bringing the microetching agent into contact with the copper surface is not particularly limited. For example, the method of spraying the microetching agent on the surface of the copper layer to be treated, And the like. When spraying, the temperature of the microetching agent is preferably 10 to 40 ° C., and the etching is preferably performed under a spray pressure of 0.03 to 0.3 MPa for 5 to 120 seconds. In the case of immersion, it is preferable that the temperature of the microetching agent is 10 to 40 ° C. and etching is performed for 5 to 120 seconds. In the case of immersion, in order to oxidize cuprous ions generated in the microetching agent by copper etching into cupric ions, it is preferable to blow air into the microetching agent by bubbling or the like. . The microetching agent of the present invention can be easily treated after use, and can be treated by a simple method using, for example, neutralization with an alkali or a polymer flocculant.

The L ^* value of the copper surface after the roughening treatment with the microetching agent is preferably 70 or less, and more preferably 65 or less. The L ^* value is the lightness L ^* in the L ^* a ^* b ^* color space (JIS Z 8781-4), and is measured by the method described in the examples described later. Untreated copper foil has a metallic luster, and L ^* is about 80 to 90. In the copper foil having a roughened surface, incident light is irregularly reflected in multiple directions, and is repeatedly reflected and attenuated. Therefore, when the roughening of the copper foil proceeds and a fine uneven shape is formed, the L ^* value tends to decrease.

The L ^* value on the copper surface can be controlled within the above range by adjusting the blending ratio of the microetching agent and the etching amount. In one embodiment of the present invention, the mixing ratio of the microetching agent and the etching amount (etching time) can be adjusted so that the L ^* value on the surface of the copper layer falls within the above range. For example, after the surface of the copper layer is roughened with a microetching agent, the amount of replenisher added and the timing of the replenisher added are controlled while monitoring the L ^* value on the surface of the copper layer after the roughening. You can also.

  The etching amount in the roughening treatment is not particularly limited. From the viewpoint of improving the adhesion with the resin, the etching amount is preferably 0.05 μm or more, and more preferably 0.1 μm or more. In pre-processing of solder resist coating process for printed wiring board that requires fine wiring, if the etching amount is excessively large, disconnection due to complete etching of copper layer, increase in resistance due to reduction in wiring cross-sectional area, etc. May cause problems. Therefore, the etching amount is preferably 1 μm or less, more preferably 0.7 μm or less, and further preferably 0.5 μm or less.

  When the microetching agent is used continuously, the roughening treatment may be performed while adding the replenisher. By performing the roughening process while adding the replenisher, the concentration of each component in the microetching agent being processed can be maintained appropriately. As the replenisher, an aqueous solution containing components (acid, halide ions, and the aforementioned polymer) that decrease with the progress of etching is preferable. The replenisher may contain a cupric ion source such as copper oxide. The amount of the replenisher added and the timing of the replenisher added can be appropriately set according to the concentration control range of each component. Each component in the replenisher is the same as the component contained in the above-described microetching agent. The concentration of each component in the replenisher is appropriately adjusted according to the initial concentration of the microetching agent used for the treatment. The composition of the replenishing solution may be the same as the building bath solution (microetching solution before use).

  After the roughening treatment step, the roughened surface may be washed with an acidic aqueous solution. As the acidic aqueous solution used for washing, hydrochloric acid, sulfuric acid aqueous solution, nitric acid aqueous solution and the like can be used. Hydrochloric acid is preferred because it has little influence on the roughened shape and has high detergency. The acid concentration of the acidic aqueous solution is preferably 0.3 to 35% by weight, and more preferably 1 to 10% by weight. The cleaning method is not particularly limited, and examples thereof include a method of spraying an acidic aqueous solution on the roughened copper layer surface, a method of immersing the roughened copper layer in the acidic aqueous solution, and the like.

  After the treatment with the microetching agent, in order to further improve the adhesion with the resin, the treatment may be performed with an aqueous solution of an azole or an alcohol solution. Further, after the treatment with the microetching agent, an oxidation treatment such as a brown oxide treatment or a black oxide treatment may be performed.

  Next, examples of the present invention will be described. In addition, this invention is limited to a following example and is not interpreted.

[Preparation of micro-etching agent]
Solutions (microetching agents) were prepared with the formulations shown in Table 1-1 to Table 1-2. Details of the polymers A to I are as follows. These polymers were used so that the concentration in the solution would be the amount shown in the table.

  Polymer A: Vinylpyrrolidone / N, N-dimethylaminoethylmethacrylamide amide diethylsulfate random copolymer having the following structure (weight average molecular weight: about 800,000)

  Polymer B: diallyldimethylammonium hydrochloride / sulfur dioxide alternating copolymer (weight average molecular weight of about 5000) having the following repeating units

Polymer C: Acrylamide / dimethylaminoethyl acrylate methyl chloride quaternary salt copolymer (weight average molecular weight about 2 million)
Polymer D: Dimethylaminoethyl methacrylate dimethyl sulfate quaternary salt polymer (weight average molecular weight of about 300,000)
Polymer E: diallyldimethylammonium chloride polymer (weight average molecular weight of about 300,000)

Polymer F: Poly (oxyethyleneoxypropylene (5E.O., 5P.O.)) glycol monoether (number average molecular weight of about 510)
Polymer G: Polyethyleneimine (weight average molecular weight about 70,000)
Polymer H: Polyethyleneimine (weight average molecular weight about 300)
Polymer I: Polyoxyethylene-polyoxypropylene block polymer adduct of ethylenediamine represented by the following formula

  The balance of the blending components in the table is ion exchange water. In Formulation 26, formic acid (pKa = 3.75) was added as an organic acid to Formulation 2, and the volume was made up to 1 L with ion-exchanged water. Then, a 48% aqueous sodium hydroxide solution was added dropwise to adjust the pH to 3.75 (organic acid the same pH as pKa). In Formulation 27, acetic acid (pKa = 4.76) was added as an organic acid to Formulation 2, and the volume was adjusted to 1 L with ion-exchanged water, and then adjusted to pH 4.76 by adding a 48% aqueous sodium hydroxide solution dropwise. Although these solutions contain hydrochloric acid as an inorganic acid, the organic acid salt has a composition substantially similar to that of the organic acid-based etching agent because the organic acid salt is adjusted to a pH region exhibiting buffering ability. In addition, pH of the solution of the mixing | blending 1-25 using only an inorganic acid was 1.0 or less.

[Copper treatment with micro-etching agent]
A glass cloth epoxy resin-impregnated copper clad laminate (product name: MCL-E-67, 10 cm × 10 cm, thickness 0.2 mm, manufactured by Hitachi Chemical Co., Ltd.) in which a 35 μm-thick copper foil is laminated on both sides of an insulating substrate, 18 μm A copper substrate was prepared as a test substrate. Next, each microetching agent (30 ° C.) shown in Table 1-1 to Table 1-5 is sprayed on the surface of the copper plating layer of the test substrate under a spray pressure of 0.10 MPa, and an etching amount of 0.5 μm. Etching was carried out by adjusting the etching time so that Next, the substrate was washed with water, and the etched surface was immersed in hydrochloric acid (hydrogen chloride concentration: 3.5% by weight) at a temperature of 30 ° C. for 10 seconds, followed by washing with water and drying.

  The surface of the copper layer of the test substrate after the treatment was observed with a scanning electron microscope (SEM) (model JSM-7000F, manufactured by JEOL Ltd.). SEM observation images are shown in FIGS. Table 1-1 and Table 1-2 show the correspondence between the composition of each solution and the SEM observation image.

<Adhesion evaluation by solder heat resistance test>
A glass cloth epoxy resin impregnated prepreg (manufactured by Hitachi Chemical Co., Ltd., product name: GEA-67N, thickness 0.1 mm) is laminated and pressed on the etched surface of the test substrate after drying (press pressure: 30 MPa, temperature: 170 ° C.). , Time: 60 minutes). Next, a test piece was produced by cutting off the peripheral portion of the laminated substrate. The test piece was left in an environment of 120 ° C. (relative humidity: 100%) for 2 hours, and then immersed in a molten solder bath at 230 ° C. for 30 seconds. Each test piece after immersion was visually observed, and A (see FIG. 20) where no swelling was observed, and B (see FIG. 21) where swelling occurred in an area within 10% of the surface. ), And those in which swelling occurred in an area of 10% or more of the surface were evaluated as X (see FIG. 22). The results are shown in Table 1-1 and Table 1-2. In addition, if the adhesiveness of copper foil and resin is favorable, a swelling will not be seen.

<Roughened surface evaluation by L ^* value>
About the etching process surface of the test board | substrate after the said drying, three places were selected arbitrarily, L ^* value was measured with the Konica Minolta company color difference meter (model: CR-10), and the average value was computed. The results are shown in Table 1-1 and Table 1-2.

From the results of Table 1-1 and Table 1-2, there is a correlation between the L ^* value of the roughened copper surface and the solder heat resistance test result, and the smaller the L ^* value, the better the solder heat resistance. It can be seen that the adhesion between the surface and the resin is good.

In the blends 1 to 3 using the polymer A, the L ^* value on the copper surface after roughening was 55 or less, and a roughened shape excellent in adhesion to the resin was formed (see FIGS. 1 to 3). ). In Formulations 1 to 3, the concentration of each component is greatly different, but the molar concentration ratio between the halogen and cupric ions and the weight concentration ratio between the cupric ions and the polymer are within the predetermined ranges, so the equivalent roughening It is considered that a shape is formed.

In formulations 4 to 7, the L ^* value on the copper surface after roughening was 65 or less. On the other hand, in Formulations 13-17 (refer FIG. 9), the L ^* value of the copper surface after roughening was large compared with Formulations 1-11, and formation of the roughening shape was inadequate.

  From these results, it can be seen that by adjusting the blending ratio of halide ions, cupric ions and polymer, a roughened shape having excellent adhesion to the resin can be formed even with a low etching amount of about 0.5 μm.

In the blends 8 to 11 (see FIGS. 4 to 7) containing the polymers B to E instead of the polymer A, the L ^* value on the copper surface after the roughening was 65 or less as in the blends 1 to 7. On the other hand, in Formulation 18 (see FIG. 8) in which no polymer was blended and in Formulations 20 and 21 (see FIGS. 12 and 13) containing polymer G (high molecular weight polyethyleneimine), the surface was roughened, but in Blend 1 Compared to ˜11, the L ^* value of the copper surface after roughening was large, and the formation of the roughened shape was insufficient.

Formulations 18 and 19 (see FIGS. 10 and 11) containing polymer F (nonionic surfactant without quaternary ammonium salt) and Formulations 22 and 23 containing polymer H (low molecular weight polyethyleneimine) (FIG. 14) 15), the surface was hardly roughened at any polymer concentration, and the L ^* value was larger than that of the formulation 12 containing no polymer. In the blends 24 and 25 using the polymer I (derivative polymer of ethylenediamine), the copper surface was not roughened at any polymer concentration.

  From these results, when using a polymer having a quaternary ammonium group in the side chain and using an inorganic acid solution in which the mixing ratio of cupric ion, halide ion, and polymer is within a predetermined range, it is peculiar. In particular, it can be seen that a fine uneven shape having excellent adhesion can be formed on the copper surface.

In the organic acid solutions of Formulations 26 and 27 adjusted to buffer pH by adding organic acid, the L ^* value on the copper surface after roughening is larger than that of Formulations 1 to 11, and the formation of the roughened shape is not good. It was enough. One possible reason that the formation of the roughened shape is insufficient is that the pH is high and the solubility of copper ions generated by etching is low. In addition, since the organic acid is easily coordinated to the cupric ion, the effective concentration of the cupric ion was lowered in the solutions of Formulation Examples 26 and 27, and the balance between the cupric ion and the halide ion concentration was lost. Is considered to be involved in the fact that the roughened shape was insufficient.

In the blends 8 to 11 (see FIGS. 4 to 7) containing the polymers B to E instead of the polymer A, the L ^* value on the copper surface after the roughening was 65 or less as in the blends 1 to 7. On the other hand, in Formulation 12 (see FIG. 8) in which no polymer was blended and in Formulations 20 and 21 (see FIGS. 12 and 13) containing Polymer G (high molecular weight polyethyleneimine), the surface was roughened but in Formulation 1 Compared to ˜11, the L ^* value of the copper surface after roughening was large, and the formation of the roughened shape was insufficient.

Claims (9)

A copper microetching agent used for surface roughening of copper,
Including inorganic acids, cupric ions, halide ions, and cationic polymers;
The cationic polymer is a water-soluble polymer having a weight average molecular weight of 1000 or more containing a quaternary ammonium group in the side chain,
A microetching agent in which the molar concentration of halide ions is 5 to 100 times the molar concentration of cupric ions.   The microetching agent of Claim 1 whose molar concentration of a cupric ion is 0.001-0.5 mol / L.   The microetching agent according to claim 1 or 2, wherein the molar concentration of halide ions is 0.01 to 10 mol / L.   The microetching agent according to any one of claims 1 to 3, wherein the polymer has a weight concentration of 0.0005 to 0.5 g / L.   The microetching agent according to any one of claims 1 to 4, wherein the pH is 2 or less.   The microetching agent according to any one of claims 1 to 5, wherein the weight concentration of cupric ions is 50 to 2000 times the weight concentration of the polymer. A method of manufacturing a wiring board including a copper layer,
The manufacturing method of a wiring board which has a roughening process process which makes the microetching agent of any one of Claims 1-6 contact the copper surface, and roughens a copper surface.   The method for manufacturing a wiring board according to claim 7, wherein an average etching amount in a depth direction when the copper surface is roughened is 1 μm or less. In the roughening treatment step, a replenisher composed of an acidic aqueous solution containing an inorganic acid, a halide ion, and a polymer is added to the microetching agent,
The method for manufacturing a wiring board according to claim 7 or 8, wherein the polymer in the replenisher is a water-soluble polymer having a side chain containing a quaternary ammonium group and having a weight average molecular weight of 1000 or more.