Electroless plating solution, method for electroless plating using the same and method for manufacturing circuit board

The present invention relates to an electroless plating solution capable of embedding plated metal in a trench or via hole formed in a printed wiring board or the like without defects, an electroless plating method using the same, and a method for manufacturing a wiring board.

Conventionally, various plating methods have been adopted as a method for manufacturing a multilayer substrate having fine wiring having a line width of 20 μm and a line spacing of 20 μm. For example, in the semi-additive method as an example, when forming a copper circuit, electroless copper plating is performed as a base for electrolytic copper plating, a circuit pattern is formed by a resist, and a copper circuit is formed by electrolytic copper plating. It is a plating technology.

However, as the line width and line spacing become narrower, the following problems arise in this semi-additive method. That is, the formation of the resist tends to cause misalignment, poor development, and the like, and disconnection and short circuit of the circuit are likely to occur. In addition, after the electrolytic copper plating process, it is necessary to remove the electroless copper plating formed as a base for energizing the electrolytic copper plating by etching. There is also a problem that short circuits occur.

An example of another method is the full additive method. This full additive method is a plating technique in which a catalyst is applied to a base material on which via holes are formed, a circuit pattern is formed by a resist, and a copper circuit is formed only by electroless copper plating.

However, as the line width and line spacing become narrower, the following problems arise in this full additive method as well. That is, the formation of the resist tends to cause misalignment, poor development, and the like, and also tends to cause disconnection and short circuit. Further, due to the construction method, a catalyst remains under the resist, but when the circuit is miniaturized, the remaining catalyst causes a decrease in insulation between the circuits, which may lead to a short circuit.

In order to solve such a problem, a method of forming trenches and via holes on the substrate surface using a laser and embedding the trenches and via holes with electroless copper plating has been attempted.

However, the conventional techniques for embedding trenches and the like by electroless plating are techniques for forming circuits having trenches and via holes having a diameter or width of 1 μm (= 1000 nm) or less on a wafer, and are printed wiring boards. Plating metal cannot be sufficiently embedded in large trenches and via holes with a diameter or width of several μm to a hundred and several tens of μm used in.

In addition, with the electroless plating solution currently used for via holes, although it is possible to embed it by increasing the plating thickness, the plating grown from the side wall sticks to each other near the opening of the via hole, and the plating grows from the opening. A gap (void or seam) is generated at the lower part, causing disconnection or the like.

Furthermore, in the existing technology, the sulfur-based compound contained for the purpose of suppressing the generation of voids and seams is used for the acidic copper sulfate electroplating solution conventionally used for filled via hole plating and dual copper damascene. When used in a highly alkaline electroless plating solution, it is unstable and self-decomposes, and it is not possible to maintain a stable state and performance for a long time, which is not practical (Patent Document 1 and Patent). Reference 2)

<p><patcit num="1"><text>Japanese Unexamined Patent Publication No. 2000-80494</text></patcit><patcit num="2"><text>International Publication No. 05/028088 Pamphlet</text></patcit></p>

<p> The present invention has been made in view of these problems of the prior art, and is good even for a large trench or via hole of several μm to one hundred and several tens of μm without causing defects such as voids and seams. An object of the present invention is to provide an electroless plating solution capable of maintaining stable performance for a long period of time, an electroless plating method using the same, and a method for manufacturing a wiring board. To do.</p>

<p> As a result of diligent studies to solve the above problems, the present inventors have made stable even in a highly alkaline plating solution by using an electroless plating solution containing a sulfur-based organic compound having a cyclic group. It has been found that the plated metal can be embedded in the trench or the via hole without causing a defect while maintaining the state of being in the state for a long time.</p><p> That is, the electroless plating solution according to the present invention is<u style="single">An electroless plating solution for embedding metal in trenches or via holes formed on a printed wiring board.</u>At least water soluble<u style="single">Copper salt or water-soluble nickel salt</u>And a leveler composed of at least one sulfur-based organic compound represented by any of the following general formulas (I) to (V), as well as containing a reducing agent and a complexing agent.<u style="single">However, the content of the sulfur-based organic compound is 0.05 mg / L to 50 mg / L.</u>.. R¹-(S)_n-R² (I) R¹-L¹-(S)_n-R² (II) R¹-L¹-(S)_n-L²-R² (III) R¹-(S)_n-L³ (IV) R¹-L¹-(S)_n-L³ (V) In the above general formulas (I) to (V), n is an integer of 1 or more, R.¹, R²Is an aliphatic cyclic group or an aromatic cyclic group containing an arbitrary number of carbon atoms, oxygen atoms, phosphorus atoms, sulfur atoms, and nitrogen atoms, respectively, or any one or more substituents on the cyclic group. One or more bonded cyclic groups, L¹, L²Is any one of a group consisting of an alkyl chain, an alkylamino chain, an alkylene chain, and an alkoxy chain that are independently linear or branched, respectively, and L.³Is an alkyl group, an alkylene group, an amino group, an alkylamino group, an alkyleneamino group, a hydroxyl group, an alkylhydroxyl group, an alkylene hydroxyl group, a carboxyl group, an alkylcarboxyl group, an alkylenecarboxygroup, an alkylaminocarboxyl group, and an alkyleneaminocarboxyl group. , Nitro group, alkylnitro group, nitrile group, alkylnitrile group, amide group, alkylamide group, carbonyl group, alkylcarbonyl group, sulfonic acid group, alkylsulfonic acid group, phosphonic acid group, alkylphosphonic acid group, sulfanyl group, It is one of a group consisting of a sulfinyl group and a thiocarbonyl group.</p>

<p> According to the electroless plating solution according to the present invention, since it contains a sulfur-based organic compound having a cyclic group, the plating metal can be formed without causing defects such as voids and seams in trenches and via holes. It can be embedded and can be suitably used for manufacturing a printed wiring board that handles high-speed signals and a printed wiring board having a high wiring density. In addition, it can be used stably for a long time even in a highly alkaline plating solution.</p>

<figref num="1">It is a figure for demonstrating "the substrate surface plating thickness", "the dent", and "the plating thickness in a trench" in the plated substrate.</figref>

Hereinafter, the electroless plating solution according to the present embodiment will be described in detail.

The electroless plating solution according to the present embodiment contains a water-soluble metal salt such as a water-soluble cupric (alloy) salt or a water-soluble nickel (alloy) salt as a main component, and formsaldehyde, paraformaldehyde, glyoxylic acid or a salt thereof. , Hypophosphorous acid or a salt thereof, one or more reducing agents such as dimethylaminoborane, and complexing agents such as tetrasodium ethylenediamine tetraacetate and potassium sodium tartrate, and at least one sulfur-based organic compound. It is contained as a leveler.

The electroless plating solution according to the present embodiment contains a water-soluble metal salt such as a water-soluble cupric salt or a water-soluble nickel salt as a main component. By containing a water-soluble cupric salt or a water-soluble nickel salt as the water-soluble metal salt, an electroless copper plating solution or an electroless nickel plating solution is produced, respectively.

As the water-soluble cupric salt, for example, copper sulfate, copper chloride, copper nitrate, copper acetate, EDTA copper and the like can be used, and at least one of these water-soluble cupric salts is contained, or any proportion thereof. 2 or more types may be contained in. The concentration of the water-soluble cupric salt is preferably 0.001 mol / L to 0.2 mol / L. When copper is contained as a metal ion source, it is not limited to containing a water-soluble cupric salt, and another metal salt may be contained to generate an electrolytically-free copper alloy plating solution.

As the water-soluble nickel salt, for example, organic nickel salts such as nickel chloride, nickel sulfate, nickel nitrate, nickel acetate, nickel hypophosphate and the like can be used, and at least one of these water-soluble nickel salts is contained. Alternatively, two or more kinds may be contained in an arbitrary ratio. The concentration of this water-soluble nickel salt is preferably 0.001 mol / L to 0.2 mol / L. When nickel is contained as a metal ion source, it is not limited to containing a water-soluble nickel salt, and another metal salt may be contained to generate an electrolytically-free nickel alloy plating solution.

As the reducing agent, known reducing agents such as formaldehyde, paraformaldehyde, glyoxylic acid or a salt thereof, hypophosphorous acid or a salt thereof, dimethylaminoborane and the like can be used, and at least one of these reducing agents is contained, or Two or more kinds may be contained in an arbitrary ratio. The concentration of this reducing agent is preferably 0.01 mol / L to 0.5 mol / L.

As the complexing agent, polyamine, polyalkanolamine, polyaminopolycarboxylic acid or its salt, carboxylic acid or its salt, oxycarboxylic acid or its salt, amino acid or its salt and the like can be used, and these complexing agents can be used. At least one type may be contained, or two or more types may be contained in an arbitrary ratio. By containing this complexing agent in the electroless plating solution, the above-mentioned metal ions such as copper ions and nickel ions are stably retained even in the alkaline plating solution.

More specifically, examples of polyamines include ethylenediamine, triethylenetetramine, hexamethylenetetramine, pentaethylenehexamine and the like. Examples of polyalkanolamines include triethanolamine, diethanolamine, and triisopropanolamine. Examples of the polyaminopolycarboxylic acid include ethylenediaminetetraacetic acid (EDTA), diethylenetriaminetetraacetic acid nitrilotriacetic acid, and salts thereof. Examples of the oxycarboxylic acid include citric acid, tartaric acid, gluconic acid, malic acid and the like, or salts thereof. Examples of amino acids include glycine, glutamic acid and the like, or salts thereof.

The complexing agent contained in the electroless plating solution according to the present embodiment includes, in particular, tetrasodium ethylenediaminetetraacetic acid (EDTA-4Na), potassium sodium tartrate (Rossel salt), and trisodium hydroxyethylethylenediaminetriacetate. (HEDTA) and the like can be preferably used. The concentration of the complexing agent is preferably 0.01 mol / L to 1 mol / L, and the total concentration of the complexing agent may be 1 to 5 times the molar amount of the water-soluble metal salt. preferable.

The electroless plating solution according to the present embodiment is characterized by containing at least one sulfur-based organic compound as a leveler. The sulfur-based organic compound contained in the electroless plating solution according to the present embodiment is an aliphatic cyclic group or an aromatic cyclic group containing an arbitrary number of carbon atoms, oxygen atoms, phosphorus atoms, sulfur atoms, and nitrogen atoms. , Or a compound containing at least one cyclic group in which one or more arbitrary one or more substituents are bonded to these cyclic groups.

Specifically, the sulfur-based organic compound contained in the present embodiment is at least one compound represented by any of the following general formulas (I) to (V). R¹-(S)_n-R² (I) R¹-L¹-(S)_n-R² (II) R¹-L¹-(S)_n-L²-R² (III) R¹-(S)_n-L³ (IV) R¹-L¹-(S)_n-L³ (V) [In general formulas (I) to (V), n is an integer of 1 or more, and R¹, R²Is an aliphatic cyclic group or an aromatic cyclic group containing an arbitrary number of carbon atoms, oxygen atoms, phosphorus atoms, sulfur atoms, and nitrogen atoms, respectively, or any one or more substituents on the cyclic group. One or more bonded cyclic groups, L¹, L²Is any one of a group consisting of an alkyl chain, an alkylamino chain, an alkylene chain, and an alkoxy chain that are independently linear or branched, respectively, and L.³Is an alkyl group, an alkylene group, an amino group, an alkylamino group, an alkyleneamino group, a hydroxyl group, an alkylhydroxyl group, an alkylene hydroxyl group, a carboxyl group, an alkylcarboxyl group, an alkylenecarboxygroup, an alkylaminocarboxyl group, and an alkyleneaminocarboxyl group. , Nitro group, alkylnitro group, nitrile group, alkylnitrile group, amide group, alkylamide group, carbonyl group, alkylcarbonyl group, sulfonic acid group, alkylsulfonic acid group, phosphonic acid group, alkylphosphonic acid group, sulfanyl group, It is one of a group consisting of a sulfinyl group and a thiocarbonyl group. ].

R in the above general formulas (I) to (V)¹, R²Examples of the substituent in the above include an alkyl group, an alkylene group, an amino group, an alkylamino group, an alkyleneamino group, a hydroxyl group, an alkylhydroxy group, an alkylene hydroxyl group, a carboxyl group, an alkylcarboxyl group, an alkylenecarboxyl group and an alkylaminocarboxyl group. Alkyleneaminocarboxyl group, nitro group, alkylnitro group, nitrile group, alkylnitrile group, amide group, alkylamide group, carbonyl group, alkylcarbonyl group, sulfonic acid group, alkylsulfonic acid group, phosphonic acid group, alkylphosphonic acid group , Sulfanyl group, sulfinyl group, thiocarbonyl group and the like.

Examples of the cyclic group include a phenyl group, a naphthyl group, a furfuryl group, a pyridyl group, a thiazolyl group, a benzothiazolyl group, a pyrimidyl group, an imidazolyl group and a thiophenyl group.

The sulfur-based organic compound is not particularly limited, but as an example thereof, 2,2'-dipyridyl disulfide, 2,2'-dibenzothiazolyl disulfide, 3,3', 5 , 5'-Tetrachlorodiphenyl disulfide, 2,2'-dithiobis (5-nitropyridine), 2,2'-dithiodibenzoic acid, 2,2'-dithiodianiline, 5,5'-dithiobis (2-nitro) Benzoic acid), 4,4'-bis (2-amino-6-methylpyrimidyl) disulfide, 4,4'-dipyridylsulfide, 6,6'-dithiodinicotinic acid, 2,2'-dithiodisalicylic acid, diflufuryl Sulphide, bis (6-hydroxy-2-naphthyl) disulfide, furfurylmethyl disulfide, bis (2-benzamidephenyl) disulfide, bis (3-hydroxyphenyl) disulfide, 2-benzothiazolyl diethyldithiocarbamate, 5,5'-thio Examples thereof include disalicylic acid, 5,5'-dithiodisalicylic acid, (4-pyridylthio) acetic acid, 3- (2-benzothiazolylthio) propionic acid, 4- (2-benzothiazolylthio) formolin and the like. In particular, 2,2'-dipyridyl disulfide, 6,6'-dithiodinicotinic acid, 2,2'-dithiodibenzoic acid, bis (6-hydroxy-2-naphthyl) disulfide, etc. are used for trenches, via holes, etc. It can be preferably used from the viewpoints that the plated metal can be better embedded, the usable concentration range is wide, the change with time is unlikely to occur, and the influence of decomposition products is small.

This sulfur-based organic compound is preferably contained in a concentration range of 0.001 mg / L to 500 mg / L, more preferably in a concentration range of 0.05 mg / to 50 mg / L. When the concentration is low, the effect as a leveler cannot be fully exerted, and when the concentration is high, the effect as a leveler appears too strongly, which hinders the precipitation of plating or the substrate surface. However, the film thickness of the plating film becomes very thin both in the trench and the via hole, and it becomes impossible to embed a sufficient plating metal in the trench and the via hole. As a result, a printed wiring board with many defects is formed. Therefore, in the electroless plating solution according to the present embodiment, it is preferable to contain the sulfur-based organic compound in the concentration range of 0.05 mg / L to 50 mg / L, and by containing the sulfur-based organic compound in this range, the leveler can be used. It is possible to satisfactorily embed the plated metal in the trench or the via hole while fully exerting the effect of.

The sulfur molecules of such sulfur-based organic compounds have the property of forming a strong interaction with the metal and strongly adsorbing the sulfur molecules when they come into contact with the metal surface. Then, this sulfur-based organic compound diffuses in the plating solution together with the metal ions and is supplied into the catalyst, but the amount of supply to the inside such as trenches and via holes where the flow of the plating solution is weaker than that on the substrate surface is the substrate. It is less than the amount supplied to the surface. Therefore, the closer to the bottom of the trench or the like, the smaller the supply amount of the sulfur-based organic compound, and the smaller the inhibitory effect of the electroless plating reaction, which results in the progress of bottom-up deposition and the voids and the like inside the trench and the like. It is possible to embed a plated metal without causing defects.

Further, according to the electroless plating solution containing a sulfur-based organic compound having a cyclic group according to the present embodiment, the generation of defects such as voids and seams can be suppressed for a long period of time, and the trenches and the like can be treated. Good plating embedding property can be exhibited.

Specifically, for example, in electroless copper plating, the reducing power of the reducing agent contained in the plating solution increases as the pH rises, so the pH of the electroless plating solution used is pH 10 to 10. It is preferable to set it to 14 high alkali. In the highly alkaline plating solution, the sulfur-based organic compound used in the conventional electroless plating solution has an electron-withdrawing group such as a sulfone group or a carboxyl group, so that the thiol anion is stabilized and the disulfide is stabilized. The bond is easily broken, becomes unstable, causes self-decomposition, and cannot maintain a stable state for a long time. As a result, the occurrence of defects such as voids and seams could not be suppressed for a long period of time.

However, according to the electroless plating solution according to the present embodiment, since the sulfur-based organic compound having a cyclic group which is an electron donating group is contained, the disulfide bond is not easily broken and the condition is high alkali. It is possible to suppress the self-decomposition reaction, maintain a stable state and performance for a long period of time, and do not generate defects such as voids and seams for a long period of time. A plating film can be formed.

Furthermore, by containing a sulfur-based organic compound having a cyclic group with high adsorptivity, the flow velocity dependence on the influence of the leveler on the precipitation rate becomes large, and the effect as a leveler can be enhanced, which is better. The plated metal can be filled even in a large trench or via hole without causing defects, and a plating film having a smooth surface without unevenness can be formed.

In the electroless plating solution according to the present embodiment, the metal ion source such as the above-mentioned water-soluble cupric salt and water-soluble nickel salt, the reducing agent for the metal ion, and the metal ion source are stably retained. In addition to the complexing agent and the sulfur-based organic compound used as a leveler, a surfactant, a plating precipitation accelerator, etc. can be further contained, and an additive such as a stabilizer / film property improving agent may be contained. You can also. Hereinafter, these compounds will be described in detail, but the compounds contained in the electroless plating solution according to the present embodiment are not limited to the compounds listed below.

As the surfactant, polyoxyalkylene glycol, polyoxyalkylene glycol, alkyl ether, polyoxyalkylene glycol copolymer, polyoxyalkylene glycol alkyl ether copolymer and the like can be used, and at least these surfactants are used. One type may be contained, or two or more types may be contained in an arbitrary ratio. The concentration of this surfactant is preferably 0.1 mg / L to 10000 mg / L.

The effect of the surfactant is to make it easier for the hydrogen gas generated by the reaction to separate from the trench or via hole. Further, the following effects can be obtained.

That is, in the sulfur-based organic compound contained in the electroless plating solution according to the present embodiment, molecules tend to aggregate in the plating solution, and the surface of the plating film formed by the plating treatment has unevenness such as unevenness. Or voids such as voids are formed inside trenches, via holes, etc., resulting in poor embedding. Therefore, by incorporating the surfactants and the like listed above in the plating solution, it is possible to promote the dispersion of sulfur-based organic compound molecules and suppress the occurrence of defects such as voids and seams inside trenches and the like. Can be made to.

As the plating precipitation accelerator, polyamine, polyalkanolamine, polyaminopolycarboxylic acid or a salt thereof, chloride ion, nitrate ion, 8-hydroxy-7-iodo-5-quinoline sulfonic acid and the like can be used, and these One type of accelerator may be contained, or two or more types may be contained in an arbitrary ratio.

More specifically, examples of polyamines include ethylenediamine, triethylenetetramine, hexamethylenetetramine, pentaethylenehexamine and the like. Examples of polyalkanolamines include triethanolamine, diethanolamine, and triisopropanolamine. Examples of the polyaminopolycarboxylic acid include ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid nitrilotriacetic acid. By containing these plating metal precipitation accelerators, the plating growth effect (bottom-up effect) from the bottom of trenches, via holes, etc. can be promoted, and there are no defects such as voids and seams at a sufficient plating rate. The plating film can be formed efficiently.

Further, in the electroless plating according to the present embodiment, additives such as a stabilizer and a film property improving agent can be contained. As the stabilizer / film property improving agent, at least one known compound such as 2,2'-bipyridyl and 1,10-phenanthroline can be contained, or two or more kinds can be contained in an arbitrary ratio.

As a method of using the electroless plating solution according to the present embodiment generated by containing the compound described above, known methods and conditions of using the electroless plating solution can be applied, and there are no particular restrictions. Although not, the preferred method of use includes the use of the following conditions.

For example, a water-soluble metal salt such as copper sulfate is used as a main component, and a leveler composed of a reducing agent, a complexing agent, and a sulfur-based organic compound is contained, and a surfactant, a plating precipitation accelerator, a stabilizer, and a film property activator are added. Is contained in the solution, and the electrolytic-free plating solution according to this embodiment is bathed. A circuit pattern (trench, etc.) is formed in this plating solution by a laser or the like, pretreatment such as degreasing, washing with water, and activation is performed, and an insulating resin substrate, which is a catalyst-imparted object to be plated, is immersed. The pH of this electroless copper plating solution is not particularly limited, but is preferably pH 10 to 14. By setting the pH of the electroless copper plating solution to the range of high alkaline conditions in this way, the efficient reduction reaction of metal ions such as copper ions proceeds, and the deposition rate of the metal plating film is improved. Is obtained. The electroless plating solution according to the present embodiment may contain a pH adjuster such as sodium hydroxide, potassium hydroxide, or tetramethylammonium hydroxide in order to maintain the pH in the pH range of 10 to 14. .. Preferably, these compounds as pH regulators are diluted with water and added as appropriate.

The temperature at the time of plating the electroless plating solution according to the present embodiment is not particularly limited as long as it is a temperature at which a reduction reaction of metal ions such as copper ions derived from copper sulfate or the like occurs, but the efficiency is high. In order to cause a good reduction reaction, the plating temperature is preferably 20 to 90 ° C, particularly preferably 50 to 70 ° C.

Further, in performing the electroless plating treatment using the electroless plating solution according to the present embodiment, as a result of the metal ions being reduced to metal by the reducing agent as the plating progresses, the metal ion concentration in the plating solution is determined. The concentration of the reducing agent will decrease, and the pH will also decrease. Therefore, a water-soluble cupric salt or a water-soluble nickel salt as a metal ion source, a reducing agent, a complexing agent, a leveler, etc. are replenished in the electroless plating solution continuously or at appropriate time intervals. , It is preferable to keep their concentrations within a certain concentration range. It is preferable to measure the metal ion concentration, the reducing agent concentration, the pH, etc. in the plating solution continuously or at appropriate time intervals, and replenish them according to the measurement results.

Further, when electroless plating is performed on the insulating resin substrate to be plated, if there is a metal such as copper at the bottom of the formed trench or via hole, a catalyst is applied to the inside of the trench or via hole. The electroless plating solution may be brought into contact with each other without the need for contact. That is, the electroless plating solution is brought into contact with the inside of the trench or the like without applying the catalyst, and after the plating metal is embedded in the trench or the like, the catalyst is applied to form, for example, copper wiring or the like. In this way, when embedding the plating metal inside the trench or the like, the electroless plating solution is brought into contact without applying a catalyst so that the plating metal is embedded in order from the bottom of the trench or the like toward the opening. It becomes possible to do. Then, it is possible to suppress the overlap of plating based on the plating growth from the side wall near the opening of the trench or the like, and to suppress the occurrence of defects such as voids based on the overlap of the plating. By using the above-mentioned electroless plating solution containing a sulfur-based organic compound having a cyclic group and performing such electroless plating treatment, defects such as voids and seams are not generated in trenches and the like. , The plated metal can be embedded even better.

As described in detail above, since the electroless plating solution according to the present embodiment contains a sulfur-based organic compound in the plating solution, defects such as voids and seams are not generated. , Plating metal can be embedded in trenches, via holes, etc. Further, since the sulfur-based organic compound has a cyclic group, it is possible to maintain a stable state and performance without causing autolysis even under highly alkaline plating solution conditions, and it is possible to maintain a stable state and performance for a long time. It is possible to form a good plating film without defects. Furthermore, by having a cyclic group, it is possible to enhance the effect as a leveler, to realize better embedding of plated metal without defects in trenches and the like, to form a plating film, and to achieve unevenness. It is possible to form a plating film having a smooth surface.

According to the electroless plating solution according to the present embodiment having such an excellent effect, it can be suitably used for plating a printed wiring board that handles high-speed signals and a printed wiring board having a high wiring density. It is possible to manufacture a highly reliable and good wiring board without connection defects such as short circuits and disconnections.

The present invention is not limited to the above-described embodiment, and is included in the present invention even if there is a design change or the like within a range that does not deviate from the gist of the invention. Further, the various compounds contained in the electroless plating solution according to the above-described embodiment show an example to which the compound can be applied, and are not limited to those listed above.

<p> Hereinafter, more specific examples of the present invention will be described. The electroless plating solution according to the present invention is not limited to the following examples.</p><p> (Example 1) A laser processing machine (manufactured by Hitachi Via Mechanics Co., Ltd.) used for forming a via hole is used on a substrate on which a general insulating resin (ABF-GX13 manufactured by Ajinomoto Fine-Techno Co., Ltd.) is laminated, and the width and depth are 20 μm. A 13 μm trench (circuit) was formed.</p><p> Subsequently, the catalyst (seed layer) was applied by the catalyst application process (Sulcup process manufactured by Uemura Kogyo Co., Ltd .: Cleaner conditioner ACL-009, Predip PED-104, Catalyst AT-105, Accelerator AL-106), and the following Using the electroless copper plating solution prepared to the composition, electroless copper plating treatment was performed for 2 hours at a temperature condition of 70 ° C., and copper plating was embedded in the trench to form a copper plating film. Then, after the plating treatment, the filling property of the trench was measured by observing the cross section.</p><p> &lt;Electroless copper plating solution composition (Example 1)&gt; Copper sulfate: 0.04 mol / L EDTA: 0.1 mol / L Sodium hydroxide: 4 g / L Formaldehyde: 4 g / L 2,2'-bipyridyl: 2 mg / L Polyethylene glycol (molecular weight) 1000): 1000mg / L 2,2'-dipyridyl disulfide: 5mg / L (Example 2) Masking tape on a substrate on which a general insulating resin (ABF-GX13 manufactured by Ajinomoto Fine-Techno Co., Ltd.) is laminated as in Example 1. After pasting (851T manufactured by Sumitomo 3M Co., Ltd.), the masking tape is processed together with the laser processing machine (manufactured by Hitachi Via Mechanics Co., Ltd.) used for forming via holes, and the trench (width 10 μm, depth 16 μm) is made into the insulating resin. Circuit) was formed.</p><p> Subsequently, the catalyst (seed layer) was applied by the catalyst application process (Sulcup process manufactured by Uemura Kogyo Co., Ltd .: Cleaner conditioner ACL-009, Predip PED-104, Catalyst AT-105, Accelerator AL-106), and then. The masking tape was removed and the catalyst was applied only into the trench.</p><p> Then, using the electroless copper plating solution prepared to the following composition, electroless copper plating treatment was performed for 2 hours under a temperature condition of 60 ° C., and copper plating was embedded in the trench to form a copper plating film. Then, after the plating treatment, the filling property of the trench was measured by observing the cross section.</p><p> &lt;Electroless copper plating solution composition (Example 2)&gt; Copper sulfate: 0.04 mol / L HEDTA: 0.1 mol / L Sodium hydroxide: 4 g / L Formaldehyde: 4 g / L 2,2'-bipyridyl: 2 mg / L Polyethylene glycol (molecular weight) 1000): 1000mg / L 6,6'-dithiodinicotinic acid: 5mg / L (Comparative Example 1) Similar to Example 1, a substrate laminated with a general insulating resin (ABF-GX13 manufactured by Ajinomoto Fine-Techno Co., Ltd.) A trench (circuit) with a width of 20 μm and a depth of 13 μm was formed using a laser processing machine (manufactured by Hitachi Via Mechanics, Ltd.) used for forming via holes.</p><p> Subsequently, the catalyst (seed layer) is applied by the catalyst application process (Sulcup process manufactured by Uemura Kogyo Co., Ltd .: Cleaner conditioner ACL-009, Predip PED-104, Catalyst AT-105, Accelerator AL-106), and then Using a full additive electroless copper plating solution (Sulcup SP2 manufactured by Uemura Kogyo Co., Ltd.), electroless copper plating is performed for 2 hours at a temperature of 70 ° C, and copper plating is embedded in the trench to form a copper plating film. I let you. Then, after the plating treatment, the filling property of the trench was measured by observing the cross section.</p><p> (Comparative Example 2) A laser processing machine (manufactured by Hitachi Via Mechanics Co., Ltd.) used for forming via holes is used on a substrate on which a general insulating resin (ABF-GX13 manufactured by Ajinomoto Fine-Techno Co., Ltd.) is laminated in the same manner as in Example 1. A trench (circuit) with a width of 20 μm and a depth of 13 μm was formed.</p><p> Subsequently, the catalyst (seed layer) is applied by the catalyst application process (Sulcup process manufactured by Uemura Kogyo Co., Ltd .: Cleaner conditioner ACL-009, Predip PED-104, Catalyst AT-105, Accelerator AL-106), and then Using an electroless copper plating solution prepared to the following composition for the purpose of forming a trench circuit on the wafer, electroless copper plating was performed for 2 hours at a temperature of 70 ° C, and copper plating was embedded in the trench to make copper. A plating film was formed. Then, after the plating treatment, the filling property of the trench was measured by observing the cross section.</p><p> &lt;Electroless copper plating (Comparative example 2)&gt; Copper sulfate: 0.04 mol / L EDTA: 0.1 mol / L Sodium hydroxide: 4 g / L Formaldehyde: 4 g / L 2,2'-bipyridyl: 2 mg / L Polyethylene glycol (molecular weight 1000) : 1000mg / L Sulfopropyl sulphonate: 0.5mg / L (Comparative example 3) Masking tape (Sumitomo) on a substrate on which a general insulating resin (ABF-GX13 manufactured by Ajinomoto Fine-Techno Co., Ltd.) is laminated as in Example 2. After pasting 851T manufactured by 3M Co., Ltd., the masking tape is processed together with the laser processing machine (manufactured by Hitachi Via Mechanics Co., Ltd.) used for forming via holes, and the trench (circuit) with a width of 10 μm and a depth of 16 μm is processed into the insulating resin. Was formed.</p><p> Subsequently, the catalyst (seed layer) was applied by the catalyst application process (Sulcup process manufactured by Uemura Kogyo Co., Ltd .: Cleaner conditioner ACL-009, Predip PED-104, Catalyst AT-105, Accelerator AL-106), and masking tape was applied. Was peeled off and the catalyst was applied only into the trench.</p><p> After that, electroless copper plating was performed for 2 hours at a temperature of 70 ° C using a full additive electroless copper plating solution (Sulcup SP2 manufactured by Uemura Kogyo Co., Ltd.), and copper plating was embedded in the trench to form a copper plating film. Was formed. Then, after the plating treatment, the filling property of the trench was measured by observing the cross section.</p><p> (Comparative Example 4) A laser processing machine (manufactured by Hitachi Via Mechanics Co., Ltd.) used for forming via holes is used on a substrate on which a general insulating resin (ABF-GX13 manufactured by Ajinomoto Fine-Techno Co., Ltd.) is laminated as in Example 1. A trench (circuit) with a width of 20 μm and a depth of 13 μm was formed.</p><p> Subsequently, the catalyst (seed layer) was applied by the catalyst application process (Sulcup process manufactured by Uemura Kogyo Co., Ltd .: Cleaner conditioner ACL-009, Predip PED-104, Catalyst AT-105, Accelerator AL-106), and the following Using the electroless copper plating solution prepared to the composition, electroless copper plating treatment was performed for 2 hours at a temperature condition of 70 ° C., and copper plating was embedded in the trench to form a copper plating film. Then, after the plating treatment, the filling property of the trench was measured by observing the cross section.</p><p> &lt;Electroless copper plating solution composition (Comparative Example 4)&gt; Copper sulfate: 0.04 mol / L EDTA: 0.1 mol / L Sodium hydroxide: 4 g / L Formaldehyde: 4 g / L 2,2'-bipyridyl: 2 mg / L Polyethylene glycol (molecular weight) 1000): 1000 mg / L Acedia sulfone: 1000 mg / L (Comparative Example 5) A laser used for forming via holes on a substrate on which a general insulating resin (ABF-GX13 manufactured by Ajinomoto Fine-Techno Co., Ltd.) is laminated as in Example 1. A trench (circuit) with a width of 20 μm and a depth of 13 μm was formed using a processing machine (manufactured by Hitachi Via Mechanics, Ltd.).</p><p> Subsequently, the catalyst (seed layer) was applied by the catalyst application process (Sulcup process manufactured by Uemura Kogyo Co., Ltd .: Cleaner conditioner ACL-009, Predip PED-104, Catalyst AT-105, Accelerator AL-106), and the following Using the electroless copper plating solution prepared to the composition, electroless copper plating treatment was performed for 2 hours at a temperature condition of 70 ° C., and copper plating was embedded in the trench to form a copper plating film. Then, after the plating treatment, the filling property of the trench was measured by observing the cross section.</p><p> &lt;Composition of electroless copper plating solution (Comparative Example 5)&gt; Copper sulfate: 0.04 mol / L EDTA: 0.1 mol / L Sodium hydroxide: 4 g / L Formaldehyde: 4 g / L 2,2'-bipyridyl: 2 mg / L Polyethylene glycol (molecular weight) 1000): 1000mg / L Diphenyl sulfoxide: 100mg / L (Experimental results) Table 1 below shows the experimental results of each example and each comparative example, that is, the presence or absence of voids or seams, and the filling property of copper plating. It shows the evaluation result. In the cross-sectional observation, measurement was performed using a microscope (DMI3000M manufactured by LEICA).</p><p> In evaluating the results of this experiment, the trench forming process was different between Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 4, and Comparative Example 5 and Example 2 and Comparative Example 3 (masking tape was used). The definitions of "board surface plating thickness", "dent", and "trench in-trench plating thickness" in Table 1 below are different for each of them. Specifically, as shown in Fig. 1. is there. Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 4, and Comparative Example 5 belong to the definition of FIG. 1 (A), and Example 2 and Comparative Example 3 belong to the definition of FIG. 1 (B).</p><p><tables num="1"><img file="JP5525762B2_D0001.tif" /></tables></p><p> As shown in the results of Table 1, in Comparative Examples 1 and 3, voids or seams were generated in the trench, and the copper plating could not be sufficiently embedded in the trench. Further, in Comparative Example 2, although the occurrence of voids and seams in the trench could not be confirmed, sufficient copper plating could not be embedded in the trench.</p><p> Further, in Comparative Examples 4 and 5, although the occurrence of voids and seams in the trench could not be confirmed, sufficient copper plating could not be embedded in the trench.</p><p> In Examples 1 and 2 performed using the electroless copper plating solution according to the embodiment of the present invention with respect to these Comparative Examples 1 to 5, defects such as voids and seams were not formed in the trench. , Sufficient copper plating could be embedded in the trench. Further, as can be seen from the fact that the depth of the dent is 1/2 or less as compared with Comparative Examples 1 to 3, the thicknesses of 11.6 μm (Example 1) and 15.0 μm (Example 2) are increased. It was found that copper plating can be sufficiently embedded in the trenches that the trenches have, and that a good printed wiring board can be formed.</p><p> From this result, by performing the electroless plating treatment using the electroless plating solution according to the present embodiment, even large trenches and via holes can be sufficiently plated without causing defects such as voids and seams. It became clear that metal can be embedded.</p>