JP2007016283A - Direct plating method and palladium conductive body layer forming solution - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a direct plating method for carrying out copper electroplating directly without electroless copper plating by forming a palladium conductive body layer on an insulating part of a material to be plated such as printed circuit board and a palladium conductive body layer forming solution used for the direct plating. <P>SOLUTION: After a palladium catalyst is imparted on the surface of the insulating part by applying a palladium catalyst imparting treatment on the surface of the material to be plated, the palladium conductive body layer is formed on the insulating part by applying the palladium conductive body layer forming solution containing a palladium compound, an amine compound and a reducing agent and the copper electroplated coating film is formed on the palladium conductive body layer. Because the electroless copper plating solution which is highly alkaline is not used and the palladium conductive body forming solution which is neutral is used to make conductive in the direct plating method, the polyimide is not infringed and adverse effect on the adhesiveness does not occur. Further the palladium conductive body layer is not formed on copper by adding an azole compound into the palladium conductive body layer forming solution, the reliability to the connection between a copper part and the copper electroplated coating film existing on a substrate is made remarkably high. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  In the present invention, it is possible to perform direct copper plating without performing electroless copper plating on an insulating portion of an object to be plated, and insulating portions of through holes (TH) and blind via holes (BVH) such as printed wiring boards. Suitable for direct plating method and direct plating, especially effective for copper plating on rigid-flex substrates having polyimide as a material and built-up substrate which is a full surface resin. The present invention relates to a palladium conductor layer forming solution.

  Conventionally, the base plating on the insulating portion of the printed wiring board has been performed mainly in the electroless copper plating process. Typical processes employ a Pd—Sn alloy colloid as a catalyst or an alkaline Pd ion solution as a catalyst and a metallization of Pd with a reducing agent solution in the next step as a pretreatment method. There is a method of applying electroless copper plating. By this plating process, most printed wiring boards can make the insulating portion conductive. However, it has become difficult to support flexible substrates and rigid flex substrates used in mobile phones, digital cameras, HD and DVD devices, and the like. The reason for this is that despite the fact that many electroless copper plating solutions are highly alkaline, functional groups such as amino groups, hydroxyl groups, carbonyl groups, and carboxylic acid groups are generated by this alkaline solution in the polyimide material, making it hydrophilic. It is mentioned that water absorption becomes high by having. Due to this characteristic, when long-term treatment is performed with an electroless copper plating solution that is highly alkaline, the plating solution soaks into the polyimide base material, and after the plating treatment, the soaking plating solution remains between the plating film and the polyimide, The problem is that copper is oxidized and causes poor adhesion. In addition, the adhesive layer used in such a substrate is easily dissolved in an alkaline solution, and the eluate becomes a factor of reducing the deposition rate of electroless copper plating, leading to a short life of the liquid.

  In order to solve these problems, there is currently a process using a direct plating method in which electroplating is performed without electroless copper plating on the object to be plated without using highly alkaline electroless copper plating solution. There are many.

  Japanese Patent No. 266662 (Patent Document 1) describes a method in which electroplating can be performed by changing a Pd—Sn colloidal catalyst to a metal chalcogenide conversion coating by sulfidation.

  Japanese Patent No. 2799076 (Patent Document 2) describes a method in which a metal coating by galvanic action is performed after a treatment with a colloidal acidic solution of a noble metal stabilized with an organic polymer, followed by a sulfidation treatment.

  In Japanese Patent No. 3117216 (Patent Document 3), after forming an oxide thin film layer with a potassium permanganate aqueous solution adjusted to pH 0-6 with sulfonic acids, a conductive polymer layer of a pyrrole derivative is formed, and electroplating is performed. A method is described.

  In Japanese Patent No. 3284289 (Patent Document 4) and Japanese Patent No. 3261469 (Patent Document 5), a carbon layer is deposited on the surface, treated in an acidic solution to remove carbon from the copper surface, and electroplating is performed. The method of application is described.

  However, many of these pretreatment processes require a copper etching step after the step of forming the conductive layer. The reason for this is that in the case of an object to be plated consisting of an insulating part and a copper part, such as a printed wiring board having a through hole and / or a via hole, the component used to form the conductive layer on the copper is replaced or replaced. This is because if there is no step of adsorbing and removing the component, the connection reliability between copper and the copper plating film existing on the substrate may be lowered. In addition, the copper etching process is considered to be technically more difficult than the process of dissolving ordinary copper because the components used to form the conductive layer are deposited on the copper. In addition, the conductive layer applied to the insulating portion may be slightly dissolved or dropped by the acid cleaning in the copper etching treatment and the copper sulfate plating pretreatment.

  In addition, in patent documents and general literatures, there are those described for neutral electroless copper plating solutions, but they are on the market because of the difficulty in using expensive reducing agents and maintaining solution stability. The current situation has not yet reached.

Japanese Patent No. 2660002 Japanese Patent No. 2799076 Japanese Patent No. 3117216 Japanese Patent No. 328489 Japanese Patent No. 3261469

  The present invention has been made in view of the above circumstances, and by forming a palladium conductor layer on an insulating portion of an object to be plated such as a printed wiring board, direct electro copper plating can be performed without performing electroless copper plating. An object is to provide a direct plating method to be performed and a palladium conductor layer forming solution used for direct plating.

  As a result of intensive studies to achieve the above object, the present inventor has given a palladium catalyst to the surface of the insulating portion by applying a palladium catalyst applying treatment to the surface of the object to be plated including the insulating portion. The palladium conductor layer is formed on the insulating portion by the palladium conductor layer forming solution containing the palladium compound, the amine compound and the reducing agent using the provided palladium as a catalyst. Direct copper electroplating is possible without interposing an electroless copper plating film, and in this case, in this method, a part to be plated such as a printed wiring board having a through hole and / or a via hole is an insulating part. It is effective for the conductive treatment of the insulating part for the object to be plated containing the copper part and the palladium conductor layer formation When formulated with azole compound in the liquid, without forming a palladium conductor layer on the copper portion, it is obtained by finding that only can be selectively be formed a palladium conductor layer on the insulating portion.

  More specifically, the conventional electroless copper plating treatment adversely affects polyimide having low alkali resistance. That is, the highly alkaline electroless copper plating solution erodes the polyimide surface, and after the electroless copper plating treatment, the plating solution leaks onto the polyimide surface to oxidize the electroless copper plating film and lower the plating adhesion. it is conceivable that.

  In order to solve these problems, the present invention is a process in which a palladium catalyst is applied to an insulator and then a palladium conductor layer is formed. Preferably, palladium is added to the insulator by an acidic palladium colloid catalyst. After providing the catalyst, the palladium conductor layer is formed by a palladium conductor layer forming solution containing a palladium compound, an amine compound and a reducing agent. Further, this palladium conductor layer forming solution can form a palladium conductor layer in the vicinity of neutrality, and by using a palladium conductor layer forming solution containing an azole compound, the palladium conductor layer forming solution on copper is formed. There is no formation. This is because the use of an acidic palladium colloid or the like for the application of the palladium catalyst does not cause any problem in the palladium conductor layer formation treatment even if palladium is not applied or is applied to copper more or less. This is because the palladium conductor layer is not formed on the copper by containing the azole compound in the body layer forming solution.

  Thus, in the present invention, the electroless copper plating solution that is highly alkaline is not used, and the conductor formation is performed with the neutral palladium conductor layer forming solution. No adverse effects occur. In addition, the palladium conductor layer can be dried once and then proceed to electrolytic copper plating, which is the next step, instead of the continuous treatment of immediately copper plating. Moreover, since formation of the palladium conductor layer on copper does not occur by adding an azole compound to the palladium conductor layer forming solution, the copper portion existing on the substrate and the electrolytic copper plating film (hereinafter, The connection reliability of copper-copper is abbreviated.

  Conventionally, in the patent literature relating to electroless palladium plating, the insulating part is immersed in the plating solution by imparting catalytic properties by a conventionally known sensitizing-activator method, catalyst-accelerator method, etc. It is said that the plating process can be carried out, but the palladium conductor layer is used only for obtaining conductivity after applying a palladium catalyst to the resin surface such as TH and BVH on the general surface called a printed wiring board. There is no known base treatment process for the purpose of performing electrolytic copper plating on an insulating portion such as a resin portion via the palladium conductor layer. Furthermore, the palladium conductor layer is selectively formed only on the insulating portion, and the palladium conductor layer is not formed on the metal part such as copper, that is, the copper existing on the substrate surface is not dissolved. Further, neither a palladium conductor layer forming solution nor an electroless palladium plating solution is known.

Accordingly, the present invention provides the following direct plating method and palladium conductor layer forming solution.
Claim 1:
A method of performing electrolytic copper plating on an insulating part of an object to be plated including an insulating part, and applying a palladium catalyst to the surface of the object to be plated to give a palladium catalyst to the surface of the insulating part. Then, using the provided palladium as a catalyst, a palladium conductor layer is formed on the insulating portion by a palladium conductor layer forming solution containing a palladium compound, an amine compound and a reducing agent, and then the palladium conductor A direct plating method comprising forming an electrolytic copper plating film directly on a layer.
Claim 2:
The direct plating method according to claim 1, wherein the substrate of the object to be plated is made of polyimide.
Claim 3:
The part to be plated of the object to be plated includes an insulating part and a copper part, the palladium conductor layer forming solution further contains an azole compound, and the object to be plated is formed into the palladium conductor layer. 3. The direct plating method according to claim 1, wherein the palladium conductor layer is selectively formed only on the insulating portion without forming the palladium conductor layer on the copper portion by treating with a solution.
Claim 4:
The direct plating method according to claim 3, wherein the azole compound is benzotriazole.
Claim 5:
The direct plating method according to claim 3 or 4, wherein the object to be plated is a printed wiring board having through holes and / or via holes.
Claim 6:
6. The direct plating method according to claim 1, wherein the palladium conductor layer forming solution has a pH of 8 or less.
Claim 7:
The direct plating method according to any one of claims 1 to 6, wherein the application of the palladium catalyst is carried out by treatment with an acidic palladium colloid solution dispersed and stabilized with an organic polymer.
Claim 8:
A palladium conductor layer forming solution for use in direct plating, comprising a palladium compound, an amine compound, and a reducing agent.
Claim 9:
Furthermore, the palladium conductor layer forming solution of Claim 8 containing an azole compound.
Claim 10:
The palladium conductor layer forming solution according to claim 8 or 9, wherein the azole compound is benzotriazole.
Claim 11:
The palladium conductor layer forming solution according to any one of claims 8 to 10, which has a pH of 8 or less.

The direct plating method and palladium conductor layer forming solution of the present invention have the following effects.
(1) Since a conductor layer (palladium conductor layer) is formed in a short time with a neutral solution, liquid penetration into the polyimide does not occur when an object to be plated made of a polyimide substrate is used.
(2) Since the conductor layer on the polyimide is formed of palladium, there is no metal oxidation over time and excellent adhesion.
(3) Since palladium is less likely to be oxidized than copper, the layer thickness is about 5 to 50 nm, and sufficient conductivity is obtained, and it is not necessary to immerse in the treatment liquid for a long time.
(4) Since palladium is more excellent in corrosion resistance than copper, it can be stored for a long period of time after the formation of the palladium conductor layer and before electrolytic copper plating treatment such as copper sulfate plating.
(5) The process by the conventional electroless copper plating pretreatment can also be used.
(6) When a palladium conductor layer forming solution containing an azole compound is used, there is no conductor layer on the copper portion of the surface of the object to be plated, so that etching after forming the conductor layer is unnecessary.
(7) Similarly, since there is no conductor layer on the copper portion, the connection reliability between copper and copper is high.

  In the direct plating method of the present invention, as described above, an electrolytic copper plating film is formed on the insulating part of the object to be plated including the insulating part, and a palladium catalyst is applied to the surface of the object to be plated. To give a palladium catalyst to the surface of the insulating part, and then to the insulating part by a palladium conductor layer forming solution containing a palladium compound, an amine compound and a reducing agent using the provided palladium as a catalyst. A palladium conductor layer is formed, and then an electrolytic copper plating film is directly formed on the palladium conductor layer of the insulating portion.

  Here, as the object to be plated, all the parts to be plated may be insulative, or include an insulating part and a copper part, for example, a printed wiring board having a copper film having through holes and / or via holes. In particular, a rigid-flex substrate having polyimide as a material, a built-up substrate which is a full surface resin, and the like can be given.

  In the present invention, the pretreatment method up to the palladium catalyst application treatment may employ a known method, for example, in the case of a printed wiring board having a copper film, such as an amine compound containing a nonionic activator or a cationic activator. After conditioning with an alkaline cleaner, a method of performing copper etching with an etching solution containing an oxidizing agent and an acid, and further pickling is employed.

  In addition, the palladium catalyst can be applied to the insulating portion of the object to be plated by a known method, for example, a conventionally known sensitizing / activator method, Pd—Sn colloid catalyst, alkaline Pd ion type, and acidity. A Pd colloid type or the like can be used.

  In this case, considering the reduction in the number of steps and the cost, the Pd—Sn colloid catalyst requires a step of removing Sn, which may impair the connection reliability between copper and copper, and alkaline Pd ions If it is a type of catalyst, the step of reducing the Pd after the treatment is required, so the most preferable is an acidic Pd colloid solution that is dispersed and stabilized with an organic polymer.

  In addition, as an activator processing agent used for such palladium catalyst provision, it can be set as a well-known composition, and a commercial item can also be used. Moreover, the process conditions can employ | adopt well-known normal conditions.

  Next, the palladium conductor layer forming solution for forming the palladium conductor layer is a complex of a palladium compound with an amine compound and contains a reducing agent.

  Here, as the palladium compound to be used, known compounds can be used, and water-soluble such as palladium oxide, palladium chloride, palladium nitrate, palladium acetate, sodium palladium chloride, potassium potassium chloride, palladium ammonium chloride, palladium sulfate, tetraammine palladium chloride and the like. And palladium compounds. The use concentration of the palladium compound is preferably in the range of 0.0001 to 0.01 mol / L. Most preferred is 0.0005 to 0.002 mol / L. If the concentration is less than 0.0001 mol / L, the rate at which the palladium conductor layer is formed becomes slow. If the concentration exceeds 0.01 mol / L, the cost is increased in terms of economy and the palladium exceeds 0.01 mol / L. There is a possibility that palladium may be substituted or deposited on copper at a concentration.

  The palladium conductor layer forming solution of the present invention preferably uses at least one amine compound in order to stably form and maintain a palladium complex. In this case, the pH of the palladium conductor layer forming solution is Since it is maintained in the vicinity of 7, a compound that stably forms a complex at that pH is selected. The concentration of the amine compound is preferably 0.0001 to 0.1 mol / L, more preferably 0.001 to 0.02 mol / L. The higher the concentration of the amine compound, the more stable the liquid stability. However, when the concentration exceeds 0.1 mol / L, the strength of dissolving the copper on the substrate becomes stronger, and the concentration of copper in the palladium conductor layer forming solution increases. . When the copper concentration is increased, the formation rate of the conductor layer is decreased, and thus the lifetime of the palladium conductor layer forming solution may be shortened. On the other hand, when the concentration is less than 0.0001 mol / L, the palladium complex is not formed, and the palladium conductor layer forming solution is suspended, which may cause precipitation in the course of time.

  Examples of the amine compound include monoamines such as methylamine, ethylamine, propylamine, trimethylamine, and dimethylethylamine, diamines such as methylenediamine, ethylenediamine, tetramethylenediamine, and hexamethylenediamine, diethylenetriamine, triethylenetetramine, and pentaethylene. Examples of polyamines such as hexamine and other amino acids include ethylenediaminetetraacetic acid and its sodium salt, potassium salt, ammonium salt, nitrilotriacetic acid and its sodium salt, potassium salt, ammonium salt, glycine, and iminodiacetic acid.

  In addition, it is desirable to add an aliphatic carboxylic acid to improve stability. For example, formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, dicarboxylic acid as monocarboxylic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, maleic acid, fumaric acid, citraconic acid , Itaconic acid, and other carboxylic acids such as tricarballylic acid, glycolic acid, lactic acid, malic acid, tartaric acid, citric acid, isocitric acid, alloisocitric acid, gluconic acid, oxalic acetic acid, diglycolic acid and sodium salts of these carboxylic acids , Potassium salts, ammonium salts and the like.

  One or more carboxylic acids and salts thereof can be used. The concentration is preferably 0.0001 to 0.1 mol / L, more preferably 0.001 to 0.02 mol / L. If the concentration is less than 0.0001 mol / L, the effect as a stabilizer is weak, and if the concentration exceeds 0.1 mol / L, the role as a stabilizer is sufficient. Not practical.

  Known reducing agents can be used, and examples thereof include hypophosphorous acid and salts thereof, borohydride and salts thereof, dimethylamine borane, trimethylamine borane, and hydrazines.

  The reducing agent functions as a reducing agent for palladium ions in the palladium conductor layer forming solution of the present invention, and its concentration is preferably 0.01 to 1 mol / L, more preferably 0.05 to 0.5 mol / L. . When the concentration is less than 0.01 mol / L, the reaction rate decreases, and when it exceeds 1 mol / L, the palladium conductor layer forming solution may become unstable.

  It is preferable to add an azole compound to the palladium conductor layer forming solution of the present invention in order to avoid the formation of a palladium conductor layer on the copper portion surface of the object to be plated. The azole compound is adsorbed on the copper and suppresses the dissolution of the copper by the amine, thereby suppressing the substitution reaction of palladium on the copper and forming the palladium conductor layer only on the insulating portion.

  In this case, the azole compound used in the present invention is, for example, an imidazole such as imidazole, 2-phenylimidazole, 1-vinylimidazole, benzimidazole, 2-butylbenzimidazole, 2-phenylethylbenzimidazole, 2-aminobenzimidazole. , 1,2,4-triazole, 3-amino-1,2,4-triazole, 1,2,3-benzotriazole, 1-hydroxybenzotriazole, carboxybenzotriazole and other triazoles, tetrazole, 5-phenyl And tetrazole such as -1H-tetrazole, 5-methyl-1H-tetrazole and 5-amino-1H-tetrazole, pyrazole, benzothiazole and the like. In particular, 1,2,3-benzotriazole is preferable.

  Two or more of the above azole compounds may be used in combination. The concentration of the azole compound is preferably 0.0001 to 0.2 mol / L, more preferably 0.0002 to 0.02 mol / L. When the concentration is less than 0.0001 mol / L, palladium substitution or deposition occurs on copper, which may impair the connection reliability between copper and copper. Alternatively, the palladium conductor layer may not be formed smoothly due to copper dissolution in the liquid. Even if the concentration exceeds 0.2 mol / L, there is no problem if it dissolves, but it is not practical in terms of cost.

  The palladium conductor layer forming solution of the present invention is preferably used in the pH range of 8 or less, particularly in the range of pH 6-8. A favorable palladium conductor layer can be formed in this pH range. If it is less than pH 6, formation of an amine complex will become weak and formation of a palladium conductor layer may become difficult. On the other hand, when pH exceeds 8, dissolution of copper may occur, and formation of a conductor layer on an insulator may be suppressed. The treatment temperature can be used in the range of 20 to 80 ° C., and particularly a good palladium conductor layer can be formed in a short time at 40 ° C. or higher. If it is less than 20 degreeC, reaction may not start and the case where a uniform palladium conductor layer cannot be formed will arise. Moreover, when it exceeds 80 degreeC, stability of a liquid may fall. The treatment time with the palladium conductor layer forming solution is preferably 0.5 to 5 minutes, particularly about 1 to 3 minutes.

  In the present invention, the palladium conductor layer is formed with a palladium conductor layer forming solution containing the reducing agent using palladium added to the insulating portion as a catalyst. In this case, the palladium conductor layer has a film thickness of about 5 to 50 nm and has sufficient conduction for performing electrolytic copper plating. Moreover, by adding an azole compound, the compound adheres and protects on copper, and suppresses the action of dissolving copper by the palladium conductor layer forming solution and the substitution and precipitation of palladium. Thereby, it is possible to ensure high connection reliability between copper and copper.

  After the palladium conductor layer is thus formed, copper plating is performed. In this case, since the palladium conductor layer is formed on the insulating portion of the object to be plated, the copper electroplating can be performed directly on the palladium conductor layer without further electroless copper plating on the insulating portion. In particular, there is no need to interpose electroless copper plating using an alkaline electroless copper plating solution.

  In addition, the plating solution used for these electrolytic copper plating can be made into a well-known composition, and a commercial item can be used. The plating conditions may also be normal known conditions. Here, copper sulfate plating is preferable as the electrolytic copper plating, but is not limited thereto.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.

  First, as the process up to the provision of the palladium catalyst before forming the palladium conductor layer, No. 1 shown in Table 1 was used. 1-No. As the palladium conductor layer forming solution for forming the palladium conductor layer, any one of the compositions A to D shown in Table 2 was used.

（１）：ノニオン及びカチオン活性剤を含むアミン化合物のアルカリ溶液
（２）：過酸化水素の安定剤
（３）：酸性パラジウムコロイドの溶液（パラジウム溶液）
（４）：酸性パラジウムコロイドの溶液（還元剤）
（５）：アルカリ性パラジウム錯体の溶液（パラジウム溶液）
（６）：アルカリ性パラジウム錯体の溶液（キレート剤）
（７）：ジメチルアミンボラン溶液
（８）：ｐＨ調整剤（緩衝剤）
（９）：Ｐｄ−Ｓｎコロイドの溶液（安定剤）
（１０）：Ｐｄ−Ｓｎコロイドの溶液（Ｐｄ−Ｓｎ溶液）
（１１）：ほうフッ化物溶液
＊（１）〜（１１）の薬品は上村工業（株）製

(1): Alkali solution of amine compound containing nonion and cationic activator (2): Stabilizer of hydrogen peroxide (3): Solution of acidic palladium colloid (palladium solution)
(4): Acidic palladium colloid solution (reducing agent)
(5): Solution of alkaline palladium complex (palladium solution)
(6): Alkaline palladium complex solution (chelating agent)
(7): Dimethylamine borane solution (8): pH adjuster (buffer)
(9): Pd—Sn colloid solution (stabilizer)
(10): Pd—Sn colloid solution (Pd—Sn solution)
(11): Boron fluoride solution * Chemicals (1) to (11) are manufactured by Uemura Kogyo Co., Ltd.

（１２）エチレンジアミン
（１３）１，２，３−ベンゾトリアゾール

(12) Ethylenediamine (13) 1,2,3-benzotriazole

[Example 1]
The palladium conductor layer forming solution dissolves copper slightly with an amine compound. The copper dissolution produces a copper complex, which suppresses the formation of a palladium conductor layer and prevents a good and conductive palladium conductor layer from being obtained. Therefore, an azole compound, which is a chemical that suppresses copper dissolution, was added. 0.002 mol / L of BTA (1,2,3-benzotriazole), triazole, hydroxybenzotriazole, and phenylbenzotriazole was added to the composition solution shown in D of Table 2, respectively, and the FR-4 substrate was added to the 500 mL solution. It was left to stand at 50 ° C. for 14 hours while being immersed in 1 dm ² . As a result, when the same amount of azole compound was added, an effect of suppressing copper dissolution was observed as compared with the case of no addition. In particular, BTA was remarkably effective. The results are shown in Table 3.

[Example 2]
Samples obtained by completely dissolving the surface laminated copper foil of the commercially available product FR-4 by etching and two 75 μm-thick polyimide films: Kapton (manufactured by DuPont) and Upilex (manufactured by Ube Industries), No. 1 in Table 1. Treatment was performed with an acidic palladium colloidal solution containing no Sn as shown in No. 1, and a palladium conductor layer was formed with a palladium conductor layer forming solution having the composition shown in A of Table 2 at pH 7, 50 ° C. for 2 minutes. As a result, an 8 nm palladium conductor layer was formed on all the resins of FR-4 and the polyimide film, and 500 mΩ was obtained with a conduction resistance of 100 mm (width 50 mm). The palladium conductor layer was confirmed not to be peeled off by a tape test.

Thereafter, with a cathode current density of 2.5 A / dm ² , copper sulfate pentahydrate 80 g / L, sulfuric acid 200 g / L, chloride ion 60 ppmn and copper sulfate plating additive EPL-1-4A 0 manufactured by Uemura Kogyo Co., Ltd. Electroless copper plating of 25 μm was performed with an electrolytic copper plating solution containing 5 ml / L and EPL-1-B 20 ml / L. The entire surface of copper was completely applied on all of the FR-4 and polyimide films. Further, the sample was heat-treated at 150 ° C. for 1 hour, but no blistering occurred.

[Example 3]
Commercially available FR-4 substrate (0.3 mmφ, 1.6 mmt) with through holes drilled, polyimide two-layer board (upilex material) and three-layer board (kapton material) were processed in the same manner as in Example 2 up to copper sulfate plating. went. As a result, the copper sulfate plating film was completely applied in the through hole without any problem.

[Example 4]
A sample in which the surface-laminated copper foil of the commercially available product FR-4 was completely dissolved by etching and two types of 75 μm-thick polyimide films (Kapton and Upilex) were used as No. 1 in Table 1. Treatment was performed with an alkaline palladium complex solution containing no Sn as shown in No. 2, and a palladium conductor layer was formed with a palladium conductor layer forming solution having the composition shown in B of Table 2 at pH 7, 50 ° C. for 2 minutes. As a result, an 8 nm palladium conductor layer was formed on all the resins of FR-4 and two polyimide films, and 1 kΩ was obtained with a conduction resistance of 100 mm (width 50 mm). The palladium conductor layer was confirmed not to be peeled off by a tape test.

Thereafter, with a cathode current density of 2.5 A / dm ² , copper sulfate pentahydrate 80 g / L, sulfuric acid 200 g / L, chloride ion 60 ppm and copper sulfate plating additive EPL-1-4A 0 manufactured by Uemura Kogyo Co., Ltd. Electrolytic copper plating with a thickness of 25 μm was performed with an electrolytic copper plating solution containing 5 ml / L and 20 ml / L of EPL-1-B. The entire surface of copper was completely applied on all of the FR-4 and polyimide films. Further, the sample was heat-treated at 150 ° C. for 1 hour, but no blistering occurred.

[Example 5]
Commercially available FR-4 substrate (0.3 mmφ, 1.6 mmt) with through-holes drilled, polyimide bilayer plate (Upilex material) and trilayer plate (Kapton material) were treated in the same manner as in Example 4 until copper sulfate plating. went. As a result, the copper sulfate plating film was completely applied in the through hole without any problem.

[Example 6]
A sample in which the surface-laminated copper foil of the commercially available product FR-4 was completely dissolved by etching and two types of 75 μm-thick polyimide films (Kapton and Upilex) were used as No. 1 in Table 1. The Pd—Sn colloidal solution shown in 3 was used to form a palladium conductor layer with a palladium conductor layer forming solution having the composition shown in C of Table 2 at pH 7, 50 ° C. for 2 minutes. As a result, a 10 nm palladium conductor layer was formed on all of the FR-4 and polyimide film resins, and 830 mΩ was obtained with a conduction resistance of 100 mm (width 50 mm). It was confirmed that the palladium conductor layer was not removed by the tape test.

Thereafter, with a cathode current density of 2.5 A / dm ² , copper sulfate pentahydrate 80 g / L, sulfuric acid 200 g / L, chloride ion 60 ppm and copper sulfate plating additive EPL-1-4A 0 manufactured by Uemura Kogyo Co., Ltd. Electrolytic copper plating with a thickness of 25 μm was performed with an electrolytic copper plating solution containing 5 ml / L and 20 ml / L of EPL-1-B. The entire surface of copper was completely applied on all of the FR-4 and polyimide films. Further, the sample was heat-treated at 150 ° C. for 1 hour, but no blistering occurred.

[Example 7]
Commercially available FR-4 substrate (0.3 mmφ, 1.6 mmt) with through holes drilled, polyimide two-layer board (upilex material) and three-layer board (kapton material) were processed in the same manner as in Example 6 until copper sulfate plating. went. As a result, the copper sulfate plating film was completely applied in the through hole without any problem.

[Comparative Example 1]
Two types of 75 μm-thick polyimide films (Kapton and Upilex) The Pd—Sn colloidal solution shown in FIG. 3 was used for treatment, and electroless copper plating was performed with a general electroless copper plating solution at 35 ° C. for 20 minutes. As a result, the copper plating film was formed on the entire surface without swelling. However, it was confirmed that the film did not adhere to the polyimide and peeled off instantaneously in the tape test.

[Comparative Example 2]
A sample in which the surface-laminated copper foil of the commercially available product FR-4 was completely dissolved by etching and two types of 75 μm-thick polyimide films (Kapton and Upilex) were used as No. 1 in Table 1. The conductive resistance was measured for 100 mm (width: 50 mm) without performing the palladium conductor layer formation treatment, but the measurement was impossible due to the lack of conductivity. .

Thereafter, with a cathode current density of 2.5 A / dm ² , copper sulfate pentahydrate 80 g / L, sulfuric acid 200 g / L, chloride ion 60 ppm and copper sulfate plating additive EPL-1-4A 0 manufactured by Uemura Kogyo Co., Ltd. Electrolytic copper plating with a thickness of 25 μm was performed with an electrolytic copper plating solution containing 5 ml / L and 20 ml / L of EPL-1-B. The copper plating film did not deposit on all the resins of FR-4 and the polyimide film.

Claims (11)

  A method of applying copper electroplating to an insulating part of an object to be plated including an insulating part, and applying a palladium catalyst to the surface of the object to be plated to give a palladium catalyst to the surface of the insulating part Then, using the provided palladium as a catalyst, a palladium conductor layer is formed on the insulating portion by a palladium conductor layer forming solution containing a palladium compound, an amine compound and a reducing agent, and then the palladium conductor A direct plating method comprising forming an electrolytic copper plating film directly on a layer.   The direct plating method according to claim 1, wherein the substrate of the object to be plated is made of polyimide.   The part to be plated of the object to be plated includes an insulating part and a copper part, the palladium conductor layer forming solution further contains an azole compound, and the object to be plated is formed into the palladium conductor layer. 3. The direct plating method according to claim 1, wherein the palladium conductor layer is selectively formed only on the insulating portion without forming the palladium conductor layer on the copper portion by treating with a solution.   The direct plating method according to claim 3, wherein the azole compound is benzotriazole.   The direct plating method according to claim 3 or 4, wherein the object to be plated is a printed wiring board having through holes and / or via holes.   6. The direct plating method according to claim 1, wherein the palladium conductor layer forming solution has a pH of 8 or less.   The direct plating method according to any one of claims 1 to 6, wherein the application of the palladium catalyst is carried out by treatment with an acidic palladium colloid solution dispersed and stabilized with an organic polymer.   A palladium conductor layer forming solution for use in direct plating, comprising a palladium compound, an amine compound, and a reducing agent.   Furthermore, the palladium conductor layer forming solution of Claim 8 containing an azole compound.   The palladium conductor layer forming solution according to claim 8 or 9, wherein the azole compound is benzotriazole. The palladium conductor layer forming solution according to any one of claims 8 to 10, which has a pH of 8 or less.