KR101312802B1 - Bonding layer forming solution and method of forming bonding layer - Google Patents

Abstract

The present invention provides an adhesive layer forming liquid capable of easily maintaining the formation performance of the adhesive layer and ensuring adhesion with the resin, and a method of forming the adhesive layer using the same.

The adhesive layer forming liquid of the present invention is an adhesive layer forming liquid for forming an adhesive layer for bonding copper and resin, and is an aqueous solution containing an acid, a first tin salt, a second tin salt, a complexing agent, and a stabilizer. When the concentration of the first tin salt is A mass% as the concentration of divalent tin ions, and the concentration of the second tin salt is B mass% as the concentration of tetravalent tin ions, the value of B / A is 0.010 or more and 1.000. It is characterized in that it is manufactured to be below.

Adhesive layer, adhesive layer forming solution, acid, stannous salt, stannous salt, complexing agent, stabilizer, tin ion, thiourea, glycol, glycol ester, tin stripping solution

Description

Adhesive layer forming liquid and adhesive layer forming method {BONDING LAYER FORMING SOLUTION AND METHOD OF FORMING BONDING LAYER}

The present invention relates to an adhesive layer forming liquid for forming an adhesive layer for bonding copper and a resin, and a method for forming an adhesive layer using the same.

A general multilayer wiring board is produced by laminating and pressing an inner layer substrate having a conductive layer containing copper on its surface with another inner layer substrate or copper foil with a prepreg interposed therebetween. The conductive wall is electrically connected by a through hole called a through hole in which the hollow wall is copper plated. In order to improve the adhesiveness with a prepreg, the tin plating layer (adhesive layer) may be formed in the conductive layer surface of the said inner layer board by the tin plating liquids described in following patent documents 1 and 2, etc.

However, the oxidation of tin plating solution of claim because the use of stannous salts of tin source, a divalent tin ion or the like using air oxidation (Sn ^{2 +)} a tetravalent tin ions (Sn ^{4 +)} as described in Patent Documents 1 and 2 It has become a problem, plating adhesion falls, and also there exists a problem that adhesiveness with resin falls.

Regarding the above problem, Patent Documents 3 and 4 below propose methods of regenerating tetravalent tin ions to divalent tin ions using metal tin.

[Patent Document 1] Japanese Patent Application Laid-Open No. 6-66553

[Patent Document 2] Japanese Patent Publication No. 2004-536220

[Patent Document 3] Japanese Patent Application Laid-Open No. 5-222540

[Patent Document 4] Japanese Patent Application Laid-Open No. 5-263258

However, in the method of the said patent documents 3 and 4, adjustment of the component in a tin plating liquid is difficult and its practicality is lacking.

This invention is made | formed in view of the said situation, and provides the adhesive layer forming liquid which can maintain the formation performance of an adhesive layer easily, and can ensure adhesiveness with resin, and the adhesive layer forming method using the same.

The adhesive layer forming liquid of the present invention is an adhesive layer forming liquid for forming an adhesive layer for bonding copper and resin, and is an aqueous solution containing an acid, a first tin salt, a second tin salt, a complexing agent, and a stabilizer. When the concentration of the first tin salt is A mass% as the concentration of divalent tin ions, and the concentration of the second tin salt is B mass% as the concentration of tetravalent tin ions, the value of B / A is 0.010 or more and 1.000. It is characterized in that it is manufactured to be below.

In addition, the adhesive layer forming method of the present invention is an adhesive layer forming method for forming an adhesive layer for bonding copper and resin, characterized in that it comprises a step of treating the copper surface with the adhesive layer forming liquid of the present invention.

In addition, "copper" in the said invention may consist of pure copper, and may consist of a copper alloy. In addition, in this specification, "copper" points out pure copper or a copper alloy.

According to the adhesive layer forming liquid of this invention and the adhesive layer forming method using the same, the formation performance of an adhesive layer can be easily maintained and adhesiveness with resin can be ensured.

The present invention is directed to an adhesive layer forming liquid for forming an adhesive layer containing a copper-tin alloy as a main component on a copper surface, and an adhesive layer forming method using the same in order to bond copper and a resin. As said copper surface, the surface of copper foil (electrolytic copper foil, rolled copper foil) used for electronic components, ornaments, building materials, etc., such as a semiconductor wafer, an electronic board | substrate, a lead frame, a copper plating film (electroless copper plating film, The surface of the electrolytic copper plating film) or the surface of the copper material of various uses, such as linear shape, rod shape, tubular shape, and plate shape, can be illustrated. Hereinafter, the component containing the adhesive layer forming liquid of this invention is demonstrated.

(mountain)

The acid contained in the adhesive layer forming liquid of the present invention functions as a pH adjuster and a stabilizer of tin ions. Examples of the acid include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid and phosphoric acid, carboxylic acids such as formic acid, acetic acid, propionic acid and butyric acid, alkanesulfonic acids such as methanesulfonic acid and ethanesulfonic acid, benzenesulfonic acid, phenolsulfonic acid and cresol. Water-soluble organic acids, such as aromatic sulfonic acids, such as sulfonic acid, can be illustrated. Among them, sulfuric acid and hydrochloric acid are preferred in view of the formation rate of the adhesive layer, the solubility of the second tin salt, and the like. Preferable concentration of the acid is 1 to 50 mass%, more preferably 3 to 30 mass%, still more preferably 5 to 20 mass%. If it is in the said range, the adhesive layer excellent in adhesiveness can be easily formed.

(First tin salt)

In the present invention, stannous salt is used as the tin source. Examples of the first tin salt include stannous sulfate, stannous boride, stannous fluoride, stannous nitrate, stannous oxide, stannous chloride, stannous formate, stannous acetate, and the like. Preferred concentrations of the stannous salt are in the range of 0.05 to 10.00 mass% as the concentration of divalent tin ions, more preferably in the range of 0.10 to 5.00 mass%, still more preferably in the range of 0.5 to 3.00 mass%. If it is in the said range, the adhesive layer excellent in adhesiveness can be easily formed.

(Secondary tin salt)

In the preparation of the adhesive layer of the present invention, in addition to the first tin salt, a second tin salt is added. Accordingly, even in the case of continuous use, the oxidation of divalent tin ions in the adhesive layer forming liquid into tetravalent tin ions by air oxidation or the like can be suppressed. As said 2nd tin salt, although it can use without a restriction | limiting in particular in the 2nd tin salt soluble in an acidic solution, Salt with the said acid is preferable from a soluble viewpoint. For example, ditin sulfate, ditin tin fluoride, ditin nitrate, ditin chloride, ditin formate, ditin acetate and the like can be exemplified. Preferred concentrations of the stannic salt are in the range of 0.01 to 5.00 mass% as the concentration of tetravalent tin ions, and more preferably in the range of 0.01 to 1.50 mass%. If it is in the said range, the adhesive layer excellent in adhesiveness can be easily formed.

The adhesive layer forming liquid of this invention made the density | concentration of the said 1st tin salt into A mass% as the concentration of divalent tin ion at the time of its manufacture, and made the concentration of the said 2nd tin salt into B mass% as the concentration of tetravalent tin ion. At this time, it is manufactured so that the value of B / A may be 0.010 or more and 1.000 or less. Here, "at the time of manufacture" refers to the time of mixing | blending at the time of mix | blending each component which comprises an adhesive layer forming liquid, and specifically, refers to the time of mixing | blending when mix | blending 1 st tin salt and 2 st tin salt. By the value of B / A being 0.010 or more at the time of preparation of an adhesive layer forming liquid, even when it is used continuously, the formation performance of an adhesive layer can be easily maintained. Moreover, adhesiveness with resin can be ensured by making B / A value 1.000 or less at the time of manufacture of an adhesive layer forming liquid. In order to exhibit the said effect more effectively, it is preferable to manufacture so that the value of B / A at the time of manufacture of an adhesion layer forming liquid may be 0.050 or more and 0.500 or less.

(Complexing agent)

The complexing agent contained in the adhesive layer-forming liquid of the present invention forms a chelate by coordinating on the underlying copper surface, thereby making it easy to form an adhesive layer on the copper surface. For example, thioureas such as thiourea, 1,3-dimethylthiourea, 1,3-diethyl-2-thiourea, thiourea derivatives such as thioglycolic acid, and the like can be used. Preferable concentration of the complexing agent is in the range of 1 to 30% by mass, more preferably in the range of 1 to 20% by mass. If it is in this range, the adhesive layer excellent in adhesiveness can be formed, without reducing the formation speed of an adhesive layer. Moreover, if it exists in this range, the adhesive layer with favorable smoothness can be formed.

(Stabilizer)

The stabilizer contained in the adhesive layer forming liquid of this invention is an additive for maintaining the density | concentration of each component required for reaction in the vicinity of a copper surface. As said stabilizer, glycols, such as ethylene glycol, diethylene glycol, propylene glycol, tripropylene glycol, glycol esters, such as a cellosolve, carbitol, and butyl carbitol, etc. can be illustrated, for example. The concentration of the stabilizer is preferably in the range of 1 to 80% by mass, more preferably in the range of 5 to 80% by mass, still more preferably in the range of 10 to 80% by mass. If it is in the said range, the density | concentration of each component required for reaction can be maintained easily in the vicinity of a copper surface.

To the adhesive layer forming liquid of the present invention, in addition to the above components, a reducing agent such as hypophosphorous acid, a brightening agent, a pH adjuster, an antiseptic, and the like can be appropriately added as necessary. Content of these additional components is about 0.1-20 mass%, for example.

The adhesive layer forming liquid of this invention can be manufactured easily by dissolving each said component in water. As said water, ionic substance and the water which removed the impurity are preferable, for example, ion-exchange water, pure water, ultrapure water, etc. are preferable.

When forming an adhesive layer using the adhesive layer forming liquid of this invention, it can form on the following conditions, for example.

First, the copper surface is washed with an acid or the like. Next, a copper surface is immersed in the said adhesive layer forming liquid, and rocking immersion treatment is performed for 5 second-5 minutes. The temperature of the adhesive layer forming liquid at this time should just be about 20-70 degreeC (preferably 20-40 degreeC). Thereafter, an adhesive layer (tin plating layer) is formed by washing with water and drying.

Moreover, the surface of this adhesive layer can also be processed with a tin peeling liquid. It is because a thin contact bonding layer can be formed more smoothly by making tin peeling liquid contact the surface of a contact bonding layer.

As said tin stripping liquid, what is necessary is just a liquid which can etch tin, For example, acidic solutions, such as nitric acid aqueous solution, hydrochloric acid, a sulfuric acid aqueous solution, these mixed solutions, etc. can be used. As acid concentration of an acidic solution, it is preferable that it is the range of 0.1-10 mass%, and it is more preferable that it is the range of 0.3-5 mass%. If it is in this range, the thickness of an adhesive layer can be easily controlled in an appropriate range. In particular, the nitric acid aqueous solution is preferable because of the high peeling speed. Moreover, you may add other additives, such as surfactant and a pH adjuster, to a tin stripping liquid.

In the surface peeling step, the contact time between the surface of the adhesive layer and the tin peeling liquid (preferably an aqueous nitric acid solution) is preferably 5 to 120 seconds, more preferably 10 to 30 seconds. If it is in this range, the thickness of an adhesive layer can be easily controlled in an appropriate range. As a method of making a tin peeling liquid contact, the liquid treatment method by dipping, spraying, etc. can be employ | adopted. In addition, the temperature of the tin stripping liquid at this time is about 25-35 degreeC.

In addition, the appropriate thickness of the adhesive layer is 0.02 μm or less, preferably 0.001 to 0.02 μm, more preferably 0.003 to 0.02 μm. When the thickness of the adhesive layer is 0.001 μm or more, the adhesiveness with the resin layer can be easily ensured. On the other hand, when the thickness of the adhesive layer is 0.02 μm or less, the adhesive layer can be easily removed when the adhesive layer needs to be removed in a subsequent step.

The constituent resin of the resin layer to be bonded to the adhesive layer is not particularly limited, but acrylonitrile / styrene copolymer resin (AS resin), acrylonitrile / butadiene / styrene copolymer resin (ABS resin), fluorine resin, polyamide, polyethylene Thermoplastic resins such as polyethylene terephthalate, polyvinylidene chloride, polyvinyl chloride, polycarbonate, polystyrene, polysulfone, polypropylene, liquid crystal polymer, epoxy resin, phenol resin, polyimide, polyurethane, bismaleimide tree Thermosetting resins, such as an azine resin, modified polyphenylene ether, and a cyanate ester, or ultraviolet curable resins, such as an ultraviolet curable epoxy resin and an ultraviolet curable acrylic resin, etc. are mentioned. These resins may be modified with a functional group or may be reinforced with glass fibers, aramid fibers, other fibers, or the like.

The adhesive layer obtained by this invention can ensure adhesiveness with an insulating resin, an etching resist, a soldering resist, a conductive resin, a conductive paste, a conductive adhesive, a dielectric resin, a resin for filling holes, a flexible coverlay film, and the like. Therefore, according to this invention, since adhesiveness of a copper layer and a resin layer can be ensured, a highly reliable wiring board can be provided, for example.

Next, the Example of this invention is described with a comparative example. In addition, this invention is not interpreted limited to the following Example.

(Process by new liquid)

The adhesive layer forming liquid (temperature: 30 degreeC) of the formulation shown in the following Table 1 was prepared by 1 liter. In addition, the remainder except the component shown in Table 1 was made into ion-exchange water also about any adhesive layer forming liquid. Then, an electrolytic copper foil (3EC-III manufactured by Mitsui-Kinjo Kogyo Co., Ltd., 35 μm in thickness) cut to 100 mm × 100 mm was prepared as a test piece, and each test piece was placed in each of the above liquids (new liquid), A rocking dipping treatment for 30 seconds was performed. Thereafter, the treated test piece was washed with water and immediately subjected to a rocking dipping treatment for 20 seconds in an aqueous 0.7 mass% nitric acid solution (temperature: 30 ° C), followed by washing with water and drying.

(Treatment by high amount)

Apart from the above, one liter of the adhesive layer forming liquid (temperature: 30 ° C.) of the formulation shown in Table 1 below was prepared, and the same test piece was prepared over 500 hours under the same conditions as above while stirring each liquid. Processing continued every time. Subsequently, the same test piece as above was put into each liquid (solid solution) after a process, and it processed on the conditions similar to the above. Thereafter, the treated test piece was washed with water and immediately subjected to a rocking immersion treatment for 20 seconds in an aqueous 0.7 mass% nitric acid solution (temperature; 30 ° C), followed by washing with water and drying.

(Adhesion)

Each test piece after processing was sampled, and the photosensitive liquid soldering resist (SR-7200 by Hitachi Kasei Kogyo Co., Ltd.) was apply | coated to the thickness of about 20 micrometers through the adhesive layer, and it hardened. Then, the peeling strength (N / mm) was measured based on JISC6471. The results are shown in Table 1.

(Tin plating adhesion)

Solid solution (temperature) which continued to process 500 sheets of the new liquid (temperature: 30 degreeC) of the adhesive layer forming liquid of the mixture shown below in Table 1, and the adhesive layer forming liquid of the formulation shown in the following Table 1 over 24 hours on the same conditions as the above. : 30 ° C.) was prepared one by one. And an electrolytic copper foil (3EC-III by Mitsui Kinzoku Co., Ltd., 35 micrometers in thickness) cut into 100 mm x 100 mm was prepared as a test piece, and this test piece was carried out one by one in each said liquid (new liquid and solid liquid). The tin plating adhesion (formation performance of the adhesive layer) was evaluated by placing the plated in less than 3 seconds by observation of the appearance, the plated in 3 to 10 seconds, the plated in 3 to 10 seconds, and the plating without plating within 10 seconds. It was.

As shown in Table 1, Examples 1 to 11 of the present invention had good results with respect to both peel strength (adhesiveness) and tin plating adhesion as compared with Comparative Examples 1 to 4.

(Sn ^{+ 4} Sn ^{+ 2} air oxidation inhibitory effect of by addition)

The adhesive layer-forming solution, thereby maintaining the pre-addition of Sn ^{+ 4} to make sure that the air oxidation of Sn ^{+ 2} inhibition, was subjected to the following experiment.

One liter of an adhesive layer forming liquid of the same formulation as in Comparative Example 4 of Table 1 was prepared, and the liquid was stirred at a temperature of 30 ° C. for 2 hours without integrally treating the test piece, and the liquid after stirring was prepared using the adhesive layer forming liquid of Comparative Example 5 ( New liquid). Then, an electrolytic copper foil (3EC-III manufactured by Mitsui-Kinjo Kogyo Co., Ltd., 35 μm in thickness) cut to 100 mm × 100 mm was prepared as a test piece, and the test piece was placed in the fresh liquid of Comparative Example 5 for 30 seconds. Rocking dipping treatment was carried out. Thereafter, the treated test piece was washed with water and immediately subjected to a rocking dipping treatment for 20 seconds in an aqueous 0.7 mass% nitric acid solution (temperature: 30 ° C), followed by washing with water and drying.

Apart from the above, 1 liter of the new liquid of Comparative Example 5 was prepared, and the same test piece as described above was continuously processed over 500 hours under the same conditions as described above while stirring the liquid. Subsequently, the same test piece as the above was put into the liquid (solid solution) after processing, and it processed on the conditions similar to the above. Thereafter, the treated test piece was washed with water and immediately subjected to a rocking dipping treatment for 20 seconds in an aqueous 0.7 mass% nitric acid solution (temperature: 30 ° C), followed by washing with water and drying.

The adhesiveness was evaluated as mentioned above about each test piece after a process. Moreover, the tin plating adhesion property was evaluated about the new liquid and solid solution of the said comparative example 5 as above, respectively. These evaluation results are shown in Table 2 together with the results of Example 4 described above.

As shown in Table 2, in Example 4, the addition of Sn ^{4 +} in advance, the density reduction due to air oxidation of the Sn ^{2 +} is suppressed, Sn ^{4 +} / Sn ^{2 +} value (i.e. the value of B / A) It can be seen that the change of is suppressed. Thereby, evaluation of adhesiveness and tin plating adhesion was favorable also in any of a new liquid and a solid liquid. On the other hand, as for the comparative example 5 containing the Sn ^{4 +} generated by the air oxidation of Sn ^{+ 2} is, showed significantly decreased concentration of the air-oxidation of Sn ^{+ 2} (Sn ^{+ 4} increasing concentration). As a result, with regard to the solid solution of Comparative Example 5, neither adhesiveness nor tin plating adhesion deteriorated. If the result from this, pre-addition of Sn ⁴⁺ in the adhesive layer-forming solution, the effect of preventing the deterioration of the adhesive layer-forming solution obtained, a Sn ^{+ 4} roneun degradation preventing effect of the adhesive layer-forming solution produced by air oxidation of Sn ^{+ 2} It can be seen that is not obtained.

Claims (8)

As an adhesive layer forming liquid which forms an adhesive layer for bonding copper and resin, An aqueous solution comprising an acid, stannous salt, stantin salt, a complexing agent, and a stabilizer, At the time of manufacture, when the density | concentration of the said 1st tin salt is made into A mass% as the concentration of divalent tin ion, and the density | concentration of the said 2nd tin salt is made into B mass% as the concentration of tetravalent tin ion, the value of B / A becomes An adhesive layer forming liquid, which is prepared to be 0.010 or more and 1.000 or less. The adhesive layer forming liquid of claim 1, wherein A is 0.05 to 10.00 and B is 0.01 to 5.00. The adhesive layer forming liquid of claim 1, wherein the complexing agent is at least one selected from thioureas and thiourea derivatives. The adhesive layer forming liquid of claim 1, wherein the stabilizer is at least one selected from glycols and glycol esters. An adhesive layer forming method for forming an adhesive layer for bonding copper and resin, A method of forming an adhesive layer, comprising the step of treating a copper surface with the adhesive layer forming liquid according to any one of claims 1 to 4. The method for forming an adhesive layer according to claim 5, wherein the step of treating the copper surface is a step of immersing the copper surface in the adhesive layer forming liquid. The method for forming an adhesive layer according to claim 5, further comprising a step of treating the surface of the obtained adhesive layer with a tin stripping liquid after the step of treating the copper surface. 8. The method of claim 7, wherein the tin stripper is an aqueous solution of nitric acid.