HK1196405B - Microetching agent for copper, supplementary liquid for same, and manufacturing method for circuit board - Google Patents

Description

Copper microetching agent, replenishment solution therefor, and method for producing circuit board

Technical Field

The invention relates to a copper microetching solution, a replenishment solution therefor, and a method for producing a circuit board.

Background

In the process of manufacturing a printed circuit board, it is common to pattern a resist layer or a resist on the surface of a copper layer by forming the resist layer or the resist with a photosensitive resin (photoresist). For example, in a semi-additive process (semi-additive process), a copper layer called a "seed layer" is formed on an insulating substrate by electroless plating, a plating resist layer is formed on the seed layer, and then patterned plating is performed on a resist opening portion on the seed layer by copper plating to form a patterned metal wiring.

The surface of a copper layer such as a seed layer is roughened as a pretreatment for forming a resin layer such as a photoresist on the copper layer. The roughening treatment is performed for the purpose of activating the surface of the copper layer, and also for the purpose of roughening the surface of the copper layer to exert an anchor effect to improve adhesion to a photoresist.

As a roughening method, the prior art includes: a method of roughening the surface of a copper layer by using a microetching agent containing a specific polymer compound described in patent document 1 or a microetching agent containing a specific organic acid described in patent document 2. Since deep irregularities can be formed on the surface of the copper layer by such roughening methods, the adhesion between the surface of the copper layer and the photoresist can be improved. [ Prior art documents ]

[ patent document ]

Patent document 1: japanese laid-open patent publication No. 9-41162

Patent document 2: japanese patent laid-open publication No. 9-41163

Disclosure of Invention

[ problems to be solved by the invention ]

In recent years, thinning of a copper layer on which a photoresist is formed (thinning by electroless plating or the like) has been progressing. For example, in the semi-additive manufacturing process, after a metal wiring is formed by pattern plating on a seed layer on which a photoresist is formed, the seed layer of a non-formation portion of the metal wiring must be removed by etching. In order to facilitate removal of the seed layer and to suppress thinning of the wiring when the seed layer is removed, the thickness of the copper layer (seed layer) is preferably as thin as possible.

As the copper layer becomes thinner, the roughening treatment of the surface of the copper layer becomes more difficult, and therefore, the activation treatment of the surface of the copper layer is changed to the rust removal by dilute sulfuric acid. On the other hand, as the pattern to be formed becomes thinner, the adhesion between the copper layer surface and the patterned resist tends to be lowered by activation treatment with dilute sulfuric acid, which leads to a problem of lowering productivity. More specifically, the photosensitive resin layer formed on the surface of the copper layer is exposed to light and then developed with a developer such as an aqueous sodium carbonate solution, and the developed pattern is used as a plating resist or a resist in the next step.

The microetching agents described in patent documents 1 and 2 are used to improve adhesion by forming deep irregularities on the surface of the copper layer, and therefore, a certain etching amount (for example, 1.5 μm or more) is required to maintain adhesion to a resin such as a photoresist. Therefore, as a pretreatment for forming the plating resist layer in the semi-additive manufacturing step, for example, when the microetching agent is used for roughening the electroless plating film (seed layer) having a thickness of 1 μm or less, the entire electroless plating film may be removed under normal conditions. Further, when the etching amount is reduced to prevent the entire electroless plated film from being removed, roughening unevenness is likely to occur, and it is difficult to secure uniform adhesion between the electroless plated film and the plating resist layer. As a result, a local defect of the plating resist pattern may occur, and a desired wiring pattern shape may not be obtained. Therefore, development of a microetching solution which can uniformly maintain adhesion to a resin such as a photoresist even at a low etching amount has been desired. The "etching amount" refers to an average etching amount (dissolution amount) in the depth direction, and is a value determined from the weight and specific gravity of copper dissolved by the microetching agent and the front projection area of the copper surface. Hereinafter, the same applies to "etching amount".

The present invention has been made in view of the problems of the prior art, and provides a microetching solution which can uniformly maintain the adhesiveness to a resin such as a photoresist even in a low etching amount, a supply solution to be added to the microetching solution, and a method for manufacturing a circuit board using the microetching solution.

[ means for solving the problems ]

The copper microetching agent of the present invention is preferably composed of an aqueous solution containing copper ions, an organic acid, halide ions, a polymer and a nonionic surfactant. The polymer is a water-soluble polymer having a polyamine chain and/or a cationic group and having a weight average molecular weight of 1000 or more. The copper microetching agent of the present invention preferably has an A/B value of 2000 to 9000 and an A/D value of 500 to 9000, where A is the concentration of the halide ion, B is the concentration of the polymer, and D is the concentration of the nonionic surfactant.

The method for manufacturing a circuit board of the present invention is a method for manufacturing a circuit board of a circuit board including a copper layer, and has a roughening treatment step of roughening a surface of the copper layer by contacting the surface with the copper microetching agent of the present invention.

The replenishment solution of the present invention is added to the copper microetching solution in the production method of the present invention, and is composed of an aqueous solution containing an organic acid, a halide ion, a polymer, and a nonionic surfactant. The polymer is a water-soluble polymer having a polyamine chain and/or a cationic group and having a weight average molecular weight of 1000 or more.

In the present invention, "copper" may be made of copper or a copper alloy. In the present specification, "copper" refers to copper or a copper alloy. In the present invention, the "copper layer" includes a copper wiring pattern layer.

[ efficacy of the invention ]

According to the present invention, the adhesion between the surface of the copper layer and the resin or the like can be uniformly maintained even at a low etching amount.

Drawings

FIG. 1 is a scanning electron micrograph (45 ℃ angle and 5000 times magnification) of a copper layer surface roughened by a microetching agent according to an example.

FIG. 2 is a scanning electron micrograph (45 ℃ angle and 5000 times magnification) of the surface of a copper layer after roughening treatment with the microetching agent of one example.

FIG. 3 is a scanning electron micrograph (45 ℃ angle and 5000 times magnification) of the surface of a copper layer after roughening treatment with the microetching agent of one example.

FIG. 4 is a scanning electron micrograph (45 ℃ angle and 5000 times magnification) of the surface of a copper layer after roughening treatment with the microetching agent of one example.

FIG. 5 is a scanning electron micrograph (45 ℃ angle and 5000 times magnification) of the surface of a copper layer after roughening treatment with the microetching agent of one example.

FIG. 6 is a scanning electron micrograph (45 ℃ angle and 5000 times magnification) of the surface of a copper layer after roughening treatment with a microetching agent of a comparative example.

FIG. 7 is a scanning electron micrograph (45 ℃ angle and 5000 times magnification) of the surface of a copper layer after roughening treatment with a microetching agent of a comparative example.

FIG. 8 is a scanning electron micrograph (45 ℃ angle and 5000 times magnification) of the surface of a copper layer after roughening treatment with a microetching agent of a comparative example.

FIG. 9 is a scanning electron micrograph (45 ℃ angle and 5000 times magnification) of the surface of a copper layer after roughening treatment with a microetching agent of a comparative example.

FIG. 10 is a scanning electron micrograph (45 ℃ angle and 5000 times magnification) of the surface of a copper layer after roughening treatment with a microetching agent of a comparative example.

Description of reference numerals:

none.

Detailed Description

[ forms of embodiment ]

The copper microetching agent of the present invention is composed of an aqueous solution containing copper ions, an organic acid, halide ions, a polymer and a nonionic surfactant. The components contained in the copper microetching agent of the present invention will be described below.

(copper ion)

The copper ions function as an oxidizing agent for oxidizing copper. The microetching solution can contain copper ions by blending a copper ion source. Examples of the copper ion source include copper salts of organic acids, copper chloride, copper bromide, copper hydroxide, and copper oxide. The organic acid forming the copper salt is not particularly limited, and is preferably an organic acid having a pKa of 5 or less, which will be described later, in view of maintaining an appropriate etching rate. The copper ion source may be used in combination of 2 or more species.

The concentration of copper ions is preferably 0.01 to 20 wt%, more preferably 0.1 to 20 wt%, and still more preferably 0.1 to 10 wt%, in view of maintaining an appropriate etching rate.

(organic acid)

The organic acid has a function of dissolving copper oxidized by copper ions and a function of adjusting pH. From the viewpoint of solubility of oxidized copper, it is preferable to use an organic acid having a pKa of 5 or less. Organic acids having a pKa of 5 or less may be mentioned: saturated fatty acids such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, and caproic acid; unsaturated fatty acids such as acrylic acid, crotonic acid and isocrotonic acid; aliphatic saturated dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, and pimelic acid; aliphatic unsaturated dicarboxylic acids such as maleic acid; aromatic carboxylic acids such as benzoic acid, phthalic acid, and cinnamic acid; hydroxycarboxylic acids such as glycolic acid, lactic acid, malic acid, and citric acid; substituted carboxylic acids such as sulfamic acid, beta-chloropropionic acid, nicotinic acid, ascorbic acid, hydroxytrimethylacetic acid and levulinic acid; and derivatives thereof, and the like. The organic acid may be used in combination of 2 or more.

The concentration of the organic acid in the microetching solution is preferably 0.1 to 30% by weight, more preferably 0.5 to 25% by weight, from the viewpoint of solubility of oxidized copper.

(halide ion)

The halide ion has a function of assisting the dissolution of copper and forming a copper layer surface having excellent adhesiveness. Halide ions can be included in the microetching solution by formulating a halide ion source. The halide ion source may be exemplified by, for example: chloride ion, bromide ion plasma sources. Specific examples thereof include: hydrochloric acid, hydrobromic acid, sodium chloride, calcium chloride, potassium chloride, ammonium chloride, potassium bromide, sodium bromide, copper chloride, copper bromide, zinc chloride, ferric chloride, stannic bromide, and the like. Examples of the halide ion source include compounds that can be dissociated in a solution to generate halide ions. The halide ion may be used in combination of 2 or more. Among them, chloride ions are preferable from the viewpoint of uniformly forming the surface of the copper layer having excellent adhesiveness. Among them, for example, copper chloride is used as a substance having both functions of a halide ion source and a copper ion source.

The concentration of the halide ion in the microetching solution is preferably 0.01 to 20% by weight, more preferably 0.1 to 10% by weight, and still more preferably 0.5 to 5% by weight, from the viewpoint of forming a copper layer surface having excellent adhesion.

(Polymer)

The polymer used in the present invention is a water-soluble polymer having a polyamine chain and/or a cationic group and having a weight average molecular weight of 1000 or more. The polymer is formulated with the halide ion to form a copper layer surface with excellent adhesion. From the viewpoint of water solubility, a polymer having a weight average molecular weight of 1000 to 5,000,000 is preferable. The "weight average molecular weight" is a value obtained by gel permeation chromatography analysis in terms of polyethylene glycol.

Specific examples of the polymer include: quaternary ammonium salt type polymers such as quaternary ammonium salt type styrene polymers, quaternary ammonium salt type aminoalkyl (meth) acrylate polymers, quaternary ammonium salt type diallylamine polymers, and quaternary ammonium salt type diallylamine-acrylamide copolymers, polymers of salts of polyethyleneimine, polyalkylene polyamine, aminoalkyl acrylamide, and cationic cellulose derivatives. Examples of the salt include hydrochloride. The polymer may be used in combination of 2 or more. Among them, from the viewpoint of uniformly maintaining the adhesion between the surface of the copper layer and the resin or the like even at a low etching amount by forming fine irregularities on the surface of the copper layer, 1 or more selected from quaternary ammonium salt polymers, polyethyleneimines, and polyalkylene polyamines are preferable, and quaternary ammonium salt polymers are more preferable. As the polymer, commercially available products such as antistatic agents for resins and fibers, polymeric flocculants for wastewater treatment, conditioning components for hair essence, and the like can be used.

The concentration of the polymer in the microetching solution is preferably 0.00001 to 1 wt%, more preferably 0.0001 to 0.1 wt%, and still more preferably 0.0002 to 0.1 wt%, from the viewpoint of forming a copper layer surface having excellent adhesion.

(nonionic surfactant)

In the microetching solution of the present invention, a nonionic surfactant can be formulated from the viewpoint of uniformly roughening the surface of the copper layer. The concentration of the nonionic surfactant in the microetching agent is preferably 0.00001 to 0.1% by weight, more preferably 0.0001 to 0.1% by weight, and still more preferably 0.0001 to 0.01% by weight, from the viewpoint of uniformly roughening the surface of the copper layer and from the viewpoint of suppressing the generation of bubbles during the treatment. The nonionic surfactant used in the present invention has no polyamine chain.

Examples of the nonionic surfactant include: polyoxyalkylene adducts such as polyol ester polyoxyethylene adducts, higher alcohol polyoxyethylene adducts, alkylphenol polyoxyethylene adducts, polyoxyalkylene alkyl ethers, acetylene glycol polyoxyethylene adducts, and the like. The nonionic surfactant may be used in combination of 2 or more. Among them, acetylene glycol polyoxyethylene adducts are particularly preferable from the viewpoint of uniformly roughening the surface of the copper layer.

The nonionic surfactant preferably has an HLB (Hydrophile-LipophileBalance: hydrophilic-lipophilic balance) of 6 to 10 from the viewpoint of uniformly roughening the surface of the copper layer. Commercially available nonionic surfactants having an HLB of 6 to 10 include, for example: surfynol440 (acetylene glycol polyoxyethylene adduct, manufactured by Nissan chemical Co., Ltd., HLB =8), Emulgen404 (polyoxyethylene oleyl ether, manufactured by Kao corporation, HLB =8.8), Newcol2303-Y (polyoxyalkylene alkyl ether, manufactured by Nippon emulsifier Co., Ltd., HLB =9.1), and the like.

In the present invention, when the concentration of the halide ion is defined as A wt%, the concentration of the polymer is defined as B wt%, the concentration of the copper ion is defined as C wt%, and the concentration of the nonionic surfactant is defined as D wt%, it is preferable that the A/B value is 2000 to 9000, and the A/D value is 500 to 9000. Thus, the surface of the copper layer can be roughened uniformly at an appropriate rate, and the adhesion between the surface of the copper layer and a resin or the like can be maintained uniformly even with a low etching amount. Also, since the etching amount can be reduced, the frequency of the renewal of the microetching agent can be reduced, so that the operation cost can be reduced. The A/B value is preferably 2100 to 9000, more preferably 2200 to 9000, and still more preferably 2400 to 9000, from the viewpoint of uniformly roughening the surface of the copper layer. From the same viewpoint, the A/D value is preferably 1000 to 9000, more preferably 1000 to 8500.

The value of A/C is preferably 0.30 to 1.40, more preferably 0.30 to 1.00, still more preferably 0.35 to 1.00, particularly preferably 0.35 to 0.95. When the value of A/C is within the above range, the roughened shape of the surface of the copper layer tends to be more uniform.

(other additives)

The microetching agent of the present invention may contain components other than those described above. For example, in the microetching solution of the present invention, salts such as sodium salts, potassium salts, or ammonium salts of organic acids may be added to reduce the pH fluctuation during the roughening treatment, and complexing agents such as ethylenediamine, pyridine, aniline, ammonia, monoethanolamine, diethanolamine, triethanolamine, and N-methyldiethanolamine may be added to improve the dissolution stability of copper, and other various additives may be added as necessary. When these additives are added, the concentration of the additives in the microetching solution is about 0.0001 to 20% by weight.

The microetching agent of the present invention can be easily prepared by dissolving the above-mentioned components in ion-exchanged water or the like.

< method for manufacturing circuit board >

The method for manufacturing a circuit board of the present invention is a method for manufacturing a circuit board including a copper layer, and includes a roughening treatment step of bringing the surface of the copper layer into contact with the microetching agent of the present invention to roughen the surface. In the case of producing a circuit board having a plurality of copper layers, only one of the plurality of copper layers may be treated with the microetching solution of the present invention, or two or more copper layer surfaces may be treated with the microetching solution of the present invention.

In the roughening treatment step, a method of bringing the surface of the copper layer into contact with the microetching agent is not particularly limited, and examples thereof include: a method of spraying a microetching agent on the surface of a copper layer to be treated, a method of immersing a copper layer to be treated in a microetching agent, and the like. In the case of spraying, it is preferable to perform etching under the conditions that the temperature of the microetching agent is set to 15 to 35 ℃, the spraying pressure is 0.03 to 0.3MPa, and 30 to 60 seconds. In the case of immersion, it is preferable to perform etching under the conditions that the temperature of the microetching agent is set to 15 to 35 ℃ for 30 to 90 seconds. In the case of immersion, it is preferable to blow air into the microetching agent by ventilation or the like in order to oxidize cuprous ions generated in the microetching agent into copper ions by etching of copper. The microetching solution of the present invention can facilitate the treatment of waste liquid after use, and can be treated by a common simple method such as neutralization or polymer flocculant.

In the present invention, the etching amount in roughening the surface of the copper layer is preferably 0.03 μm or more, and more preferably 0.05 μm or more, from the viewpoint of improving adhesion to a resin or the like. In the case of using the pretreatment step of the present invention in forming the plating resist layer on the thinned copper layer, the etching amount is preferably 1.5 μm or less, more preferably 1.0 μm or less, and still more preferably 0.5 μm or less, from the viewpoint of reducing the etching amount to prevent the removal of the entire copper layer.

In the present invention, it is preferable to wash the roughened copper layer surface with an acidic aqueous solution in order to remove the stains generated after the roughening treatment step. As the acidic aqueous solution used for washing, hydrochloric acid, an aqueous sulfuric acid solution, an aqueous nitric acid solution, and the like can be used, but hydrochloric acid is preferable in view of its small influence on the roughened shape and high stain removal property. From the viewpoint of stain removability, the acid concentration of the acidic aqueous solution is preferably 0.3 to 35% by weight, more preferably 1 to 10% by weight, and the washing method is not particularly limited, and examples thereof include: a method of spraying the roughened copper layer surface with an acidic aqueous solution, a method of immersing the roughened copper layer in an acidic aqueous solution, and the like. In the case of spraying, it is preferable to wash the surface of the substrate under conditions of an acidic aqueous solution at a temperature of 15 to 35 ℃ and a spraying pressure of 0.03 to 0.3MPa for 3 to 30 seconds. In the case of immersion, it is preferable to wash the substrate at an acidic aqueous solution temperature of 15 to 35 ℃ for 3 to 30 seconds.

The roughening treatment step is preferably a step of roughening the surface of the copper layer while adding a supply solution composed of an aqueous solution containing an organic acid, a halide ion, a polymer, and a nonionic surfactant to the microetching agent. This makes it possible to appropriately maintain the concentration of each component in the microetching solution during the treatment. The amount of the replenishment liquid to be added and the timing of addition of the replenishment liquid can be appropriately set in accordance with the concentration control range of each component. The components in the replenishment solution are the same as those contained in the microetching solution of the present invention.

The concentration of each component in the replenishment solution may be appropriately adjusted depending on the initial concentration of the microetching agent used for the treatment, and for example, if the concentration of each component in the microetching agent used for the treatment is in the range of 0.5 to 30% by weight of an organic acid, 0.01 to 20% by weight of a halide ion, 0.0001 to 1% by weight of a polymer, and 0.0001 to 1% by weight of a nonionic surfactant, the concentration of each component in the microetching agent used for the treatment can be easily maintained.

The replenishment solution can be easily prepared by dissolving the components in ion-exchanged water or the like.

After the treatment with the microetching agent of the present invention, the resin may be treated with an aqueous or alcoholic solution of pyrrole (azole) as disclosed in U.S. Pat. No. 3645772 in order to further improve the adhesion to the resin. After the treatment with the microetching agent of the present invention, an oxidation treatment called brown oxide (brown oxide) treatment or black oxide (black oxide) treatment may be performed.

The microetching agent of the present invention can be widely used for roughening the surface of a copper layer. In particular, uniform irregularities are formed on the surface of the treated copper layer, and the adhesion between the copper layer and a resin such as a prepreg, a plating resist, a solder resist, or an electrodeposition resist is good. Moreover, since the surface has excellent solderability, it is particularly useful for manufacturing various circuit boards including those for Pin Grid Array (PGA) and those for Ball Grid Array (BGA). And surface treatment of the lead frame is also useful. Among them, particularly, a copper layer having a small thickness, for example, a copper layer of 5 μm or less, particularly a copper layer having a thickness of 1 μm or less such as a copper sputtering film, a copper deposition film, a copper plating film, etc., is difficult to perform a uniform roughening treatment with a conventional microetching agent, and therefore, the effects of the present invention can be effectively exhibited. The thickness of the copper layer included in the circuit board is usually 0.3 μm or more.

The microetching agent of the present invention is particularly preferably used for surface roughening of seed layers in the production of circuit boards by the semi-additive method. That is, according to the present invention, the surface of the copper layer (seed layer) can be uniformly roughened even at a low etching amount, and therefore, even when the thickness of the copper layer is as small as 1 μm or less, the surface can be roughened without removing the entire seed layer, and the adhesion with the photoresist can be improved. In the semi-additive method, after the surface of the copper layer (seed layer) is roughened by the microetching agent of the present invention, a photoresist can be formed on the copper layer. Then, a metal wiring (usually, a copper wiring) is formed in an opening portion of the resist on the copper layer by electrolytic plating, and after the resist is removed (peeled), the copper layer in the non-metal wiring forming portion is removed by etching.

[ example ]

Next, examples of the present invention will be described together with comparative examples. The present invention is not to be construed as being limited to the following examples.

< treatment by microetching solution >

A base material having an electroless copper plating film with a film thickness of 1.0 μm was prepared as a test substrate. Next, the microetching solution was sprayed onto the electroless copper plating film of the test substrate with a spraying pressure of 0.1MPa using each of the microetching solutions (25 ℃ C.) shown in tables 1-1 to 1-6, and the time was adjusted so that the etching amount of copper became 0.1. mu.m. Then, the etching-treated surface was washed with water, immersed in hydrochloric acid (hydrogen chloride concentration: 3.5 wt%) at a temperature of 25 ℃ for 15 seconds, washed with water, and dried. The balance of the formulation components of each microetching agent shown in tables 1-1 to 1-6 was ion-exchanged water.

< evaluation of uniformity of roughening by observation with scanning type electron microscope >

Among the test substrates after the treatment, the surfaces of the electroless plating films of the substrates treated with the microetching agents of examples 1, 2, 6, 9 and 10 and comparative examples 2, 3 to 5 and 7 were observed by a Scanning Electron Microscope (SEM) (model JSM-7000F, manufactured by Nippon electronics Co., Ltd.). Fig. 1 (example 1), fig. 2 (example 2), fig. 3 (example 6), fig. 4 (example 9), fig. 5 (example 10), fig. 6 (comparative example 2), fig. 7 (comparative example 3), fig. 8 (comparative example 4), fig. 9 (comparative example 5), and fig. 10 (comparative example 7) are SEM photographs (photographing angle 45 °, magnification 5000 × magnification) taken at the time of SEM observation. From the comparison between FIGS. 1 to 5 (examples) and FIGS. 6 to 10 (comparative examples): by setting the A/B value to be in the range of 2000 to 9000 and the A/D value to be in the range of 500 to 9000, the surface of the copper layer can be uniformly roughened even at a low etching amount. In addition, when the roughening unevenness is caused, the adhesiveness may be uneven, and the adhesiveness may be poor.

< tape peeling test >

The surface of the electroless copper plating film of the treated test substrate was bonded with a dry film (No. RY-3325, thickness 25 μm) made by Hitachi chemical industries, and 80mJ/cm was exposed using a mask with a line/space =0.33mm/0.7mm as an exposure pattern²The exposure condition (2) of (4) is an exposure condition. Then theDevelopment was carried out with a 1% by weight aqueous solution of sodium carbonate (25 ℃ C.) by spraying treatment (spraying pressure 0.08MPa, spraying time 30 seconds). Then, a cellophane tape (trade name: Cellotape, product number CT405AP-18, manufactured by NICHIBAN) was applied to the developed photoresist pattern by finger pressure, and then the cellophane tape was pulled away to confirm the presence or absence of the peeling of the photoresist pattern. The results are shown in tables 1 to 6.

< survival Rate of dots (dot) >

The surface of the electroless copper plating film after the treatment was bonded with a dry film (SunfortSPG-102, thickness 10 μm) made by Asahi chemical Co., Ltd with a dot/space =20 μmA mask of 40 μm (number of dots: 255 dots) as an exposure pattern at 150mJ/cm²The exposure condition (2) of (4) is an exposure condition. Then, development was carried out with a 1% by weight aqueous solution of sodium carbonate (25 ℃ C.) by spraying treatment (spraying pressure 0.05MPa, spraying time 60 seconds). Then, the number of remaining dots after the development is counted, and the remaining dot rate is calculated as follows. The results are shown in tables 1-1 to 1-6. Further, as the residual dot ratio was higher, it was evaluated that the adhesion between the copper surface and the resist was uniformly maintained.

Dot remaining ratio (%) = dot remaining number/255 dots × 100

As shown in the results of tables 1-1 to 1-6, even with a low etching amount of 0.1 μm, any of the examples of the present invention was "no peeling" in the peeling test. In the examples of the present invention, the dot survival rate was a high value of 85% or more. On the other hand, the comparative examples obtained results in which at least one evaluation item was inferior to the examples. In particular, the remaining point ratios in the comparative examples were all low values of 65% or less. From this result, it can be known that: according to the present invention, since the surface of the copper layer can be uniformly roughened, the adhesion between the copper and the photoresist can be uniformly maintained even with a low etching amount.

Further, by examining each example and comparative example in more detail, it can be seen from the comparison between example 1 (FIG. 1), example 2 (FIG. 2), and example 6 (FIG. 3) and comparative examples 2 (FIG. 6) and 3 (FIG. 7): by using a microetching agent having an A/B value within a predetermined range, a uniform roughened shape can be obtained over the entire surface of the copper layer. Further, it can be seen that: from the comparison between example 9 (fig. 4) and example 10 (fig. 5) and comparative examples 4 (fig. 8) and 5 (fig. 9), it can be seen that: in order to obtain a uniform roughened shape, it is necessary to set the A/D value within a predetermined range, in addition to the A/B value.

From these results, it is considered that: in the present invention, by setting the concentration ratio of 3 components such as the halide ion (a), the polymer (B), and the nonionic surfactant (D) in the microetching agent within a predetermined range, a uniform roughened shape can be formed on the surface of the copper layer, and thereby the adhesion between the surface of the copper layer and the resin or the like can be uniformly maintained even with a low etching amount.

From a comparison of the dot survival rates of example 15 and example 16, it can be seen that: the use of quaternary ammonium salt type polymers as polymers in microetching agents can improve uniformity of roughening. From a comparison of the survival rates at point in example 16 and example 17, it is understood that: by using an acetylene glycol polyoxyethylene adduct as a nonionic surfactant in a microetching agent, the uniformity of roughening can be improved.

Claims (9)

1. A copper microetching agent which comprises an aqueous solution containing copper ions, an organic acid, halide ions, a polymer and a nonionic surfactant,

the polymer is a water-soluble polymer having a polyamine chain and/or a cationic group and having a weight average molecular weight of 1000 or more,

when the concentration of the halide ion is defined as A wt%, the concentration of the polymer is defined as B wt%, and the concentration of the nonionic surfactant is defined as D wt%, the A/B value is 2000-9000, and the A/D value is 500-9000.

2. The copper microetching agent according to claim 1, wherein the concentration of the halide ion is 0.01 to 20% by weight.

3. The copper microetching agent according to claim 1 or 2, wherein the polymer is at least 1 selected from the group consisting of quaternary ammonium salt polymers, polyethyleneimines, and polyalkylene polyamines.

4. The copper microetching agent according to claim 1 or 2, wherein the nonionic surfactant is a polyoxyalkylene adduct.

5. A method for manufacturing a circuit board comprising a copper layer, comprising a roughening treatment step of roughening the surface of the copper layer by contacting the surface with the copper microetching agent according to any one of claims 1 to 4.

6. The method of manufacturing a circuit board according to claim 5, wherein the thickness of the copper layer before contact with the copper microetching agent is 1 μm or less.

7. The method for manufacturing a circuit board according to claim 5 or 6, wherein an average etching amount in a depth direction at the time of roughening the surface of the copper layer is 0.5 μm or less.

8. The method for manufacturing a circuit board according to claim 5 or 6, wherein after the roughening treatment step, the surface of the roughened copper layer is washed with an acidic aqueous solution.

9. The method for manufacturing a circuit board according to claim 5 or 6, wherein the roughening treatment step is a step of roughening the surface of the copper layer while adding a replenishment solution comprising an aqueous solution containing an organic acid, a halide ion, a polymer and a nonionic surfactant to the copper microetching agent;

the polymer in the replenishing liquid contains a polyamine chain and/or a cationic group, and is a water-soluble polymer having a weight average molecular weight of 1000 or more.