JP2007098732A - Surface treated copper foil, manufacturing method of surface treated copper foil, and copper clad laminate using surface treated copper foil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface treated copper foil enhancing adhesiveness when gluing together by hot press processing of the surface treated copper foil having a silane coupling agent treated layer and a resin base material, a manufacturing method of the surface treated copper foil, and a copper clad laminate using the surface treated copper foil. <P>SOLUTION: In the surface treated copper foil having the silane coupling agent treated layer in the adhering face of the copper foil with the resin base material, the silane coupling agent treated layer is formed using a bifunctional silane coupling agent having functional groups of -Si(OCH<SB>3</SB>) at both ends of a chemical structural formula. Either one of bis-γ-trimethoxysilylpropylamine, bis-γ-trimethoxysilylpropylethylenediamine and bis-γ-trimethoxysilylethane is used as the bifunctional silane coupling agent. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a surface-treated copper foil provided with a silane coupling agent-treated layer, a method for producing the surface-treated copper foil, and a copper-clad laminate using the surface-treated copper foil.

  Conventionally, surface-treated copper foil has been widely used as a basic material for producing printed wiring boards used in the fields of electric and electronic industries. In general, an electrolytic copper foil is bonded to a polymer insulating substrate such as a glass-epoxy substrate, a phenol substrate, or a polyimide by hot press forming to form a copper-clad laminate, which is used for manufacturing a printed wiring board.

  And as surface treatment of the adhesive surface of the surface-treated copper foil, generally a rust-proofing layer in which zinc, brass, zinc-copper-nickel ternary alloy plating layer and the like and a chromate layer are arbitrarily combined, and a silane cup A ring treatment layer has been used in combination. This surface treatment layer improves adhesion to the substrate when the printed wiring board is manufactured (evaluated as the peel strength, "normal peel strength", "peel strength after heating", "chemical resistance degradation" Rate "," moisture resistance deterioration rate "," heat resistance characteristics (common name, UL characteristics) ", and" pressure cooker (PCT) test "and other evaluation items).

  For example, the deterioration rate of chemical resistance is evaluated by immersing a printed wiring board on which a copper foil circuit is formed in a hydrochloric acid solution having a predetermined concentration for a certain period of time, and how much hydrochloric acid solution is at the interface between the laminated copper foil and the substrate. In order to quantitatively evaluate whether or not it enters and erodes, the peel strength of each copper foil circuit before and after hydrochloric acid immersion is measured, and the degradation rate of the peel strength is converted into an evaluation value Therefore, it can be understood that this is an extremely important evaluation item in consideration of the state exposed to various chemicals in the printed wiring board manufacturing process. In addition, the chemical resistance of the copper foil for printed wiring boards generally requires better quality as the circuit width used for printed wiring boards becomes finer. That is, when the hydrochloric acid resistance deterioration rate becomes a large value, the solution easily enters the interface between the copper foil and the base material of the printed wiring board, and the joint interface between the copper foil and the base material tends to be eroded. As a result of exposure to various acidic solutions in the production process of the printed wiring board, it means that the risk of peeling of the copper foil circuit is increased. The importance of such characteristics is disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 4-318997) and Patent Document 2 (Japanese Patent Laid-Open No. 7-32458) for the purpose of improving the peel strength depending on the type of rust prevention treatment. It is clear from the contents of the disclosure.

  On the other hand, the silane coupling agent-treated layer of the surface-treated copper foil is in a state of being a copper-clad laminate between the rust-proof layer formed on the surface of the copper foil that is a metal and various base materials that are organic materials. A silane coupling agent treatment layer will be located. Regarding this silane coupling agent-treated layer, for example, a zinc or zinc alloy layer is formed on the surface of copper foil in Patent Document 3 (Japanese Patent Publication No. 60-15654) and Patent Document 4 (Japanese Patent Publication No. 2-19994). And the copper foil which formed the rust prevention process layer which formed the chromate layer in the surface of the said zinc or zinc alloy layer, and formed the silane coupling layer on the chromate layer is disclosed. Judging from the entirety of these documents, a characteristic feature is that after the chromate layer is formed, a drying process is performed, and then a silane coupling agent process is performed.

Japanese Patent Laid-Open No. 4-318997 JP 7-32458 A Japanese Patent Publication No. 60-15654 Japanese Patent Publication No. 2-19994 JP-B-2-17950

  However, the inventors of the present invention prepared a surface-treated copper foil on a trial basis by the methods disclosed in Patent Document 3 (Japanese Patent Publication No. 60-15654) and Patent Document 4 (Japanese Patent Publication No. 2-19994). However, the surface-treated copper foil could not stably exhibit required qualities such as normal peel strength.

  Patent Document 5 (JP-B-2-17950) describes that hydrochloric acid resistance can be improved using a copper foil treated with a silane coupling agent. However, no particular mention is made regarding moisture resistance. In recent years, delamination is a delamination phenomenon of multilayer printed wiring boards using copper-clad laminates with poor moisture resistance in the field of miniaturization of printed circuit boards, multilayered printed wiring boards, and semiconductor packages. It has been clarified that a problem occurs in the pressure cooker characteristics of the semiconductor package, which is a big problem.

  The adsorption of the silane coupling agent adsorbed on the conventional rust-proofing layer is as shown in FIG. 2 (b), with the silane coupling agent in the coating state at a level close to a monomolecular coating on the rust-proofing layer. With the goal of forming a silane coupling agent treatment layer by causing condensation reaction between the terminal group of the silane coupling agent and -OH protruding from the rust prevention treatment layer by adsorption and heating, and dehydrating. Came.

  In recent years, the trend of reducing the thickness of electronic and electrical devices has been demanded to reduce the size of the printed circuit board that is housed in the device, and the width of the copper foil circuit to be formed has become smaller. ing. Therefore, even when fine circuit wiring is formed, in order to reduce defects such as an unintended circuit peeling phenomenon, a more stable and better adhesion between the surface-treated copper foil and the resin base material is required.

  Therefore, the present inventors, in consideration of the adhesion between the surface-treated copper foil and the resin base material, how to combine the silane coupling agent and the antirust treatment layer, when the silane coupling agent is adsorbed. Considering the surface state of the rust-proofing layer and the drying conditions, it was considered necessary to establish conditions for maximizing the effects of the silane coupling agent. As a result of earnest research, by setting the adsorption and drying conditions of the silane coupling agent to the surface of the anticorrosive treatment layer to a certain condition, normal peeling strength, peeling strength after heating, etc. It was conceived that a surface-treated copper foil having excellent adhesion to the material can be obtained.

Surface-treated copper foil according to the present invention: The surface-treated copper foil according to the present invention is a surface-treated copper foil provided with a silane coupling agent-treated layer on the adhesive surface of the copper foil with the resin base material layer, and the silane coupling agent treatment layer is one formed using a bifunctional silane coupling agent having a functional group -Si (OCH ₃₎ at both ends of formula.

  And as for the said bifunctional silane coupling agent, it is preferable to selectively use what is equipped with the basic structure shown as the following Chemical formula 5.

  And more specifically, what is used as the bifunctional silane coupling agent is particularly preferably one of the following three types. The first bifunctional silane coupling agent is bis-γ-trimethoxysilylpropylamine with n = 3 and m = 1, and it is preferable to use a bis-γ-trimethoxysilylpropylamine having the basic structure shown as Chemical Formula 6 below.

  The second bifunctional silane coupling agent is bis-γ-trimethoxysilylpropylethylenediamine with n = 4 and m = 2, and it is preferable to use one having a basic structure shown as Chemical Formula 7 below.

  The third bifunctional silane coupling agent is bis-γ-trimethoxysilylethane with n = 1 and m = 0, and it is preferable to use one having the basic structure shown as the following chemical formula 8.

Method for producing surface-treated copper foil according to the present invention: The method for producing a surface-treated copper foil according to the present invention is a surface treatment for forming a silane coupling agent-treated layer on the copper foil surface using the bifunctional silane coupling agent. A method for producing a copper foil, comprising preparing a bifunctional silane coupling agent-containing solution in which the bifunctional silane coupling agent is dispersed in a solvent, and contacting the bifunctional silane coupling agent-containing solution with the copper foil surface. Forming a bifunctional silane coupling agent adsorption layer on the adhesive surface of the copper foil, and then drying in a heated atmosphere at 190 ° C. to 270 ° C. for 10 seconds to 90 minutes to form a silane coupling agent treatment layer It is characterized by comprising the characteristic silane coupling agent treatment layer.

  And when the said bifunctional silane coupling agent containing solution is used by dispersing bis-γ-trimethoxysilylpropylamine in a solvent, the solution is prepared in the range of pH 3.0 to pH 5.0. It is preferable to use it.

  In addition, the bifunctional silane coupling agent-containing solution is prepared by adjusting the solution in the range of pH 4.5 to pH 11.5 when bis-γ-trimethoxysilylpropylethylenediamine is dispersed in a solvent. It is preferable to use it.

  Furthermore, when the bis-γ-trimethoxysilylethane is dispersed in a solvent, the bifunctional silane coupling agent-containing solution is either pH 3.0 to pH 6.0 or pH 11.0 or higher. It is preferable to use one prepared in the pH range.

  In the production of the surface-treated copper foil according to the present invention, it is also preferable to use a copper foil whose surface has been subjected to roughening treatment and / or rust prevention treatment.

  And the said rust prevention process may use either inorganic rust prevention or organic rust prevention treatment.

Copper-clad laminate according to the present invention: The surface-treated copper foil provided with the silane coupling agent-treated layer according to the present invention described above is suitable as a printed wiring board material. Therefore, it is suitable for manufacturing a copper clad laminate which is a basic material of the printed wiring board.

  The surface-treated copper foil which concerns on this invention is equipped with the silane coupling agent process layer formed using the said bifunctional silane coupling agent which was not used conventionally in the adhesive surface with a resin base material. As a result, the adhesion between the surface-treated copper foil and the resin base material is improved, and a stable laminate state that is not conventionally obtained can be obtained. Therefore, by using this surface-treated copper foil, it is possible to provide a copper-clad laminate having excellent adhesion between the copper foil and the resin base material.

  And when it is going to form a silane coupling agent process layer using the said bifunctional silane coupling agent, appropriate conditions exist according to the kind of bifunctional silane coupling agent to be used. In this respect, the method for producing a surface-treated copper foil according to the present invention is a production method capable of maximizing the characteristics of a silane coupling agent-treated layer formed using a bifunctional silane coupling agent.

  Hereinafter, the surface-treated copper foil according to the present invention, a method for producing the surface-treated copper foil, and embodiments of the copper-clad laminate will be described in order.

Form of surface-treated copper foil according to the present invention: The surface-treated copper foil according to the present invention is obtained by forming a silane coupling agent-treated layer on an adhesive surface of a copper foil with a resin base material layer. Then, the silane coupling agent treatment layer is one formed using a bifunctional silane coupling agent having a functional group -Si (OCH ₃₎ at both ends of formula. By using such a bifunctional silane coupling agent, adhesiveness (adhesiveness) between a copper foil and a resin base layer that is more stable than ever can be obtained.

  The copper foil referred to here is described as including all concepts of copper foil obtained by various methods such as an electrolytic method and a rolling method. And there is no special limitation also about the thickness of this copper foil. This is because, regardless of the thickness of the copper foil, it is possible to improve the adhesion to the resin base material as compared with the conventionally used silane coupling agents. However, it is clarified that the concept of copper foil is also a concept including a copper foil with a carrier foil. Generally, the copper foil with a carrier foil is formed by depositing a copper foil layer by electrolysis on the surface of a metal foil used as a carrier foil. And when copper foil with a carrier foil is made into a copper foil with a thickness of 9 μm or less, it is used in such a manner that it is bonded to a resin base material in the state of copper foil with a carrier foil and then the carrier foil is removed. .

  Furthermore, with this copper foil, the adhesion at the time of bonding to the resin base material is improved, so roughing such as forming fine copper particles or roughing the surface of the copper foil by etching It may be a surface that has been processed. Therefore, it will be clarified that there is no problem even when there is no roughening process. Also, for the outermost layer of copper foil, from the standpoint of ensuring long-term storage, organic rust prevention treatment using imidazole and triazole agents, zinc alloys such as zinc and brass, and compositions such as nickel alloys are used. It is also possible to apply an inorganic rust prevention treatment.

Then, the silane coupling agent treatment layer is formed using a bifunctional silane coupling agent having a functional group -Si (OCH ₃₎ at both ends of formula. The formation theory of the silane coupling agent-treated layer formed at this time will be described using γ-aminopropyltrimethoxysilane (hereinafter referred to as “APS”) represented by Chemical Formula 9 used conventionally.

  The present inventors have investigated whether or not the adsorption structure of the silane coupling agent-treated layer formed on the surface of the copper foil changes due to the difference in pH when the APS is dispersed in the solvent. As a result, it has been found that the adsorption structure of the formed silane coupling agent-treated layer varies depending on the difference in pH, and a great difference occurs in the adhesion with the resin base material layer. Here, as an example, when APS is dissolved at a concentration of 0.5 wt% using water as a solvent, the solution pH becomes 10.4, and this was used to form a silane coupling agent treatment layer on the copper foil surface. In addition, the surface of the copper foil in such a case is not subjected to any rust prevention treatment. This surface-treated copper foil is referred to as “test sample 1”. In contrast, the pH was adjusted using hydrochloric acid to a solution pH of 8.5, and the case of using this to form a silane coupling agent-treated layer on the copper foil surface was compared. This surface-treated copper foil is referred to as “test sample 2”. As a result, when compared with both normal peel strengths, the surface-treated copper foil provided with the silane coupling agent-treated layer formed with a solution pH of 10.4 has better adhesion to the resin base material layer. Turned out to show. Therefore, the inventors analyzed the difference.

  First, each element in the depth direction is used for the silane coupling agent-treated layers of both surface-treated copper foils using a Marcus type high-frequency glow discharge luminescence surface analyzer (hereinafter referred to as “rf-GDOES”). The depth profile was measured. As a result, in the case of the test sample 2, as can be seen from FIG. 1 (a), the silicon (Si) peak is detected on the outermost layer, and then the carbon (C) and nitrogen (N) peaks are close to each other with a slight delay. Thus, the copper component from the bulk of the copper foil is detected with a delay of about 0.01 seconds (position 0.35 nm deep when converted from the silicon sputtering rate) in the sputtering time. On the other hand, in the case of the test sample 1, as can be seen from FIG. 1B, the peak of silicon (Si) is not present in the outermost layer, and the peak of silicon (Si) is the nitrogen (N) peak and the copper from the substrate. They are separated by (Cu) peaks. In the vicinity of the outermost layer of the test sample 1, carbon (C) and nitrogen (N) peaks appear. When the thickness of the silane coupling agent-treated layer is calculated from each silicon (Si) peak, it is 0.3 nm for test sample 2 and 1.7 nm for test sample 1. Here, in FIG. 1 (a) and FIG. 1 (b), considering the position where the detection peak of copper is steady, it is the position where the copper component from the bulk of both copper foils is reliably detected, Since both depths are the same, it is considered that there is no problem in analysis accuracy.

  Therefore, it can be considered from the above that the silane coupling agent-treated layer of the test sample 1 is thicker than the silane coupling agent-treated layer of the test sample 2. And the adsorption mechanism to the copper foil surface of the silane coupling agent will be considered to be completely different. Therefore, the present inventors assumed an adsorption model of the silane coupling agent on the copper foil surface as described below.

  FIG. 2 shows an adsorption model on the copper foil surface when APS is used as the silane coupling agent. FIG. 2A is a silane coupling agent adsorption model in the case of the test sample 2 described above. If this form is seen, like the analysis result of the above-mentioned rf-GDOES, silicon (Si), carbon (C), and nitrogen (N) peaks appear concentrated in the vicinity of the outermost layer, and are delayed from the bulk of the copper foil. It can be understood that the copper component is detected. Moreover, in the case of such an adsorption model, the point that it is estimated that the silane coupling agent is almost in the state of a monomolecular film is also consistent with the analysis result of rf-GDOES. FIG. 2 (b) shows the silane coupling agent adsorption model in the case of the test sample 1 in the most simplified form. In other words, the silane coupling agent is not only bonded to the copper foil surface, but also caused by a condensation reaction between the silane coupling agents and bonded to the copper foil surface with a planar and three-dimensional network. It is thought that the agent treatment layer is obtained. Also in this adsorption model, the analysis result of the above rf-GDOES shows that there is no silicon (Si) peak in the outermost layer and is close to the position where the copper component from the bulk of the copper foil is reliably detected. This is also supported by the fact that carbon (C) and nitrogen (N) peaks appear in the vicinity of the outermost layer of the treatment layer. Moreover, this adsorption model can provide a thick silane coupling agent-treated layer.

Therefore, the present inventors have used a bifunctional silane coupling agent having a functional group of —Si (OCH ₃ ) at both ends of the chemical structural formula, so that the silane coupling agent having the same properties as the test sample 1 is used. It was conceived that the treatment layer can be easily formed and the adhesion to the resin substrate can be stably improved. That is, formation of a silane coupling agent treatment layer having a planar and sterically crosslinked siloxane network by providing functional groups of -Si (OCH ₃ ) at both ends of the chemical structural formula of the bifunctional silane coupling agent. Is possible.

  Among the bifunctional silane coupling agents, it is preferable to selectively use those represented by the general structural formula shown as Chemical Formula 10 below. The bifunctional silane coupling agent having this general structural formula has a low possibility of adversely affecting the solution properties such as plating solution in the printed wiring board manufacturing process. This is because it has excellent delamination resistance when subjected to heat shock.

  More specifically, what is used as the bifunctional silane coupling agent is any one of the following three types of silane cups bonded in a planar and three-dimensional network by the manufacturing method described later. It is particularly preferable from the viewpoint that it is easy to form the ring agent treatment layer. In addition, the three bifunctional silane coupling agents described below can obtain high adhesion between the surface-treated copper foil and the resin base material, and the value when the adhesion is measured as the peel strength. Is stable with little variation. And as above-mentioned, it does not have bad influence on solution properties, such as plating solution in the manufacturing process of a printed wiring board, but is excellent also in the surface insulation resistance after processing to a printed wiring board, and the said delamination-proof performance.

  The first bifunctional silane coupling agent is bis-γ-trimethoxysilylpropylamine (hereinafter referred to as “BTSPA”) with n = 3 and m = 1, and has the basic structure shown as Chemical Formula 11 below. It is preferable to use a thing provided with.

  The second bifunctional silane coupling agent is bis-γ-trimethoxysilylpropylethylenediamine (hereinafter referred to as “BTSP-EDA”) having n = 4 and m = 2, and is represented by the following chemical formula 12. It is preferable to use one having a basic structure.

  The third bifunctional silane coupling agent is bis-γ-trimethoxysilylethane (hereinafter referred to as “BTSE”) having n = 1 and m = 0, and has the basic structure shown as Chemical Formula 13 below. It is preferable to use what is provided.

Production method of surface-treated copper foil according to the present invention: The method for producing a surface-treated copper foil according to the present invention is a surface treatment in which a silane coupling agent treatment layer is formed on a copper foil surface using the above-mentioned bifunctional silane coupling agent. This is a method for producing a copper foil, and is characterized by using a bifunctional silane coupling agent.

  In this production method, first, a bifunctional silane coupling agent-containing solution in which the bifunctional silane coupling agent is dispersed in a solvent is prepared. In this preparation, preparation according to the type of the solution containing the bifunctional silane coupling agent to be used is required. Hereinafter, each of the three types of bifunctional silane coupling agents will be described.

  When the BTSPA is used as the bifunctional silane coupling agent-containing solution dispersed in a solvent, the solution is preferably used as a solution prepared in the range of pH 3.0 to pH 5.0. FIG. 3 shows the relationship between the solution pH of the BTSPA-containing solution and the peel strength. Here, a pure water is used as a solvent to prepare a BTSPA-containing solution having a BTSPA concentration of 0.5 wt%, and an electrolytic copper foil having a thickness of 18 μm is added to the solution (without performing a roughening treatment, a rust prevention treatment). As a result, the silane coupling agent treatment layer is formed on the rough surface by dipping and drying by heating (200 ° C. × 60 minutes, 250 ° C. × 60 minutes). Then, a copper clad laminate was manufactured by laminating the FR-4 prepreg by hot pressing at 180 ° C. for 60 minutes. Then, a 10 mm wide linear circuit was manufactured by etching, and the peel strength was measured. At this time, the solution pH of the BTSPA-containing solution is changed between 1 and 9.5, indicating a change in peel strength. As can be seen from FIG. 3, it is understood that high adhesion is obtained by using a BTSPA-containing solution having a pH of 1 to 5. And in order to ensure the stable favorable adhesiveness with few variations, it is preferable to make pH of a BTSPA containing solution into the range of 1-4.

  In addition, when BTSP-EDA is dispersed in a solvent and used as the bifunctional silane coupling agent-containing solution, it is preferable to use a solution prepared in the range of pH 4.5 to pH 11.5. FIG. 4 shows the relationship between the solution pH of the BTSP-EDA-containing solution and the peel strength. Here, a pure water was used as a solvent to prepare a BTSP-EDA-containing solution having a BTSP-EDA concentration of 0.5 wt%, and the peel strength was measured in the same manner as in the case of using the above BTSPA. At this time, the solution pH of the BTSP-EDA-containing solution is changed between 4 and 11.5, and changes in peel strength are indicated. As can be seen from FIG. 4, when the condition of 200 ° C. × 60 minutes is used as the drying condition, high adhesion can be obtained in the range of pH 4.5 to pH 8.0. And when the conditions of 250 degreeC x 60 minutes are employ | adopted as drying conditions, it turns out that high adhesiveness is acquired in all the ranges whose pH is 4.5-11.5. From this, it can be seen that the effect of drying conditions is very large. Therefore, in order to suppress fluctuations due to drying conditions to a minimum, to reduce fluctuations, and to ensure stable and good adhesion, the pH of the BTSP-EDA-containing solution should be in the range of 4.5 to 8.5. Is preferred.

  Furthermore, when BTSE is dispersed in a solvent as the bifunctional silane coupling agent-containing solution, the solution is prepared in any pH range from pH 3.0 to pH 6.0 or pH 11.0 or higher. Is preferably used. FIG. 5 shows the relationship between the solution pH of the BTSE-containing solution and the peel strength. Here, a pure water was used as a solvent to prepare a BTSE-containing solution with a BTSE concentration of 0.5 wt%, and the peel strength was measured in the same manner as in the case of using the above BTSPA. At this time, the solution pH of the BTSE-containing solution is changed between 1.0 and 11.5, and changes in peel strength are indicated. As can be seen from FIG. 5, when conditions of 200 ° C. × 60 minutes are used as drying conditions, adhesion exceeding 0.4 kN / m is obtained in the range of pH 3.0 to pH 5.0. And when the conditions of 250 degreeC x 60 minutes are employ | adopted as drying conditions, it turns out that the adhesiveness exceeding 0.4 kN / m is obtained in pH 3.0-6.0 and the area | region 11 or more. From this, it can also be seen that there is an influence of drying conditions. Therefore, in order to suppress fluctuations due to drying conditions to a minimum, to reduce variation, and to ensure stable and good adhesion, it is preferable that the pH of the BTSE-containing solution be in the range of 3.0 to 5.0. .

  With respect to the method of adsorbing the bifunctional silane coupling agent-containing solution to the copper foil, the method is not particularly limited, such as an immersion method, a showering method, or a spraying method. In accordance with the process design, a method that allows the copper foil and the solution containing the bifunctional silane coupling agent to be most uniformly brought into contact with each other may be arbitrarily employed.

  And when making copper foil and a bifunctional silane coupling agent solution contact, it is preferable to use the wet copper foil which provided the water film on the surface rather than using dry copper foil. Compared to the former dried copper foil, the latter wet copper foil has excess water remaining on the copper foil surface when the bifunctional silane coupling agent is adsorbed and dried. For this reason, the copper foil temperature when adsorbing and drying the bifunctional silane coupling agent on the wet copper foil increases the amount of heat used to evaporate moisture from the amount of heat transferred from the ambient temperature. Even if the ambient temperature is increased to about 270 ° C., it is considered that an excessive amount of heat that leads to destruction or decomposition of the functional group of the silane coupling agent does not occur. By doing in this way, destruction or decomposition of the functional group on the side bonded to the base material of the silane coupling agent can be surely prevented, and the quality stability as the surface-treated copper foil can be improved. is there.

  These bifunctional silane coupling agents are dissolved in water as a solvent so as to have a concentration of 0.1 wt% to 15 wt%, and are used at a room temperature level. Here, when the concentration of the bifunctional silane coupling agent is less than 0.1 wt%, the adsorption rate of the bifunctional silane coupling agent is slow, and does not meet the general commercial base profit, and the adsorption is not uniform. It becomes. Even if the concentration exceeds 15 wt%, the adsorption rate is not particularly increased, and the adhesion with the substrate is not particularly improved, which is uneconomical. The higher the concentration of the bifunctional silane coupling agent, the easier the networking of the bifunctional silane coupling agents as schematically shown in Chemical formula 14 proceeds, and the silane coupling agent treatment layer to be formed tends to be thicker. It is in. At the same time, when the silane coupling agent-treated layer becomes thick, the tendency that unreacted silane coupling agent is taken into the silane coupling agent-treated layer becomes remarkable, which is not preferable.

  However, although there is a relationship with the concentration of the bifunctional silane coupling agent in the bifunctional silane coupling agent-containing solution, the contact time between the copper foil surface and the bifunctional silane coupling agent-containing solution is also important. That is, the bifunctional silane coupling agent is adsorbed in a monomolecular film form on the surface of the copper foil (including the antirust treatment layer) and condensed with an OH group on the surface is a minimum condition. The longer the contact time, the thicker the silane coupling agent treatment layer obtained. Therefore, the immersion time is preferably set to 1 minute to 30 minutes. If the immersion time is less than 1 minute on the premise that the concentration is within the above range, the adsorption amount of the bifunctional silane coupling agent on the copper foil surface is insufficient, and the adhesion between the copper foil and the resin base material is insufficient. Cannot be improved. Moreover, even if the said immersion time exceeds 30 minutes, the adsorption amount of the bifunctional silane coupling agent to the copper foil surface will be saturated, and industrial productivity will only be impaired.

  And the drying said here not only removes moisture, but also promotes the condensation reaction between the adsorbed bifunctional silane coupling agent and the OH group on the copper foil surface (including the case with a rust-proofing layer). The water generated as a result of the condensation must be completely evaporated to promote the condensation reaction between the bifunctional silane coupling agents. On the other hand, this drying temperature cannot adopt a temperature condition that destroys or decomposes the functional group of the silane coupling agent bonded to the resin constituting the resin base material when the copper foil and the resin base material are bonded together. When the functional group involved in the adhesion of the silane coupling agent to the resin base material is destroyed or decomposed, the adhesion between the copper foil and the resin base material is lost, and the effect of adsorption of the silane coupling agent is maximized. It is because it becomes impossible.

  Therefore, the bifunctional silane coupling agent-containing solution is brought into contact with the copper foil surface to form a bifunctional silane coupling agent adsorbing layer on the adhesive surface of the copper foil, and then in a heated atmosphere of 190 ° C to 270 ° C. It is preferable to form a silane coupling agent-treated layer by drying for 10 seconds to 90 minutes. It is preferable to adopt a longer drying time as the lower temperature side of the heating temperature of 190 ° C. to 270 ° C. is adopted.

  Here, when the heating atmosphere temperature is less than 190 ° C., no matter how long heating is performed, the condensation reaction between the bifunctional silane coupling agent and the OH group on the copper foil surface is promoted, Since the condensation reaction between the silane coupling agents cannot be promoted, a silane coupling agent-treated layer having quality variations is formed. Moreover, when heating atmosphere temperature exceeds 270 degreeC, the functional group which participates in adhesion | attachment with the resin base material of a silane coupling agent will be destroyed, and the adhesiveness of copper foil and a resin base material will be impaired.

  And, regarding the drying temperature, from the above-described peel strength of FIGS. 3 to 5, when the silane coupling agent treatment layer is formed by heating at 250 ° C. rather than heating at 200 ° C., It can be seen that high peel strength is obtained. That is, it is preferable to employ a drying temperature as high as possible. This is because a silane coupling agent-treated layer having a good quality can be obtained by heating in a short time.

  Even if the maximum heating temperature in the above range is adopted, the drying time is less than 10 seconds, and the condensation reaction between the bifunctional silane coupling agent and the OH group on the surface of the copper foil is promoted, and the bifunctional silane coupling agent The condensation reaction between each other cannot be promoted. When the drying time exceeds 90 minutes, even if the above-mentioned minimum heating temperature is employed, the functional group involved in the adhesion of the silane coupling agent to the resin base material is destroyed, and the copper foil and the resin base material Adhesion is impaired.

  Copper foil is a metal material, and its heat conduction speed is faster than that of organic materials such as glass materials and plastics in which silane coupling agents are generally used. It is extremely susceptible to the effects of ambient temperature and radiant heat from the heat source. Therefore, when the temperature of the copper foil itself is higher than the temperature of the air blown on the copper foil in a very short time, as in the blast mode, it is preferable to set the drying conditions with special care.

Next, the copper foil used in the manufacture of the surface-treated copper foil according to the present invention will be described. As the copper foil referred to here, a copper foil whose surface is subjected to roughening treatment and rust prevention treatment can be used. That is, it includes the concept of a copper foil that has been subjected to a roughening treatment alone, a copper foil that has been subjected to only a rust prevention treatment without performing the roughening treatment, and a copper foil that has been subjected to both the roughening treatment and the rust prevention treatment.

  These will be briefly described. When a roughening treatment and a rust prevention treatment are performed on the surface of the copper foil, the roughening treatment and the rust prevention treatment are generally performed in this order. And before this roughening treatment, etc., the surface of the copper foil is pickled and degreased to completely remove contaminants such as oil and fat components adhering to the surface, and at the same time, excess surface oxidation It is preferable to remove the film. This is to perform uniform roughening treatment and rust prevention treatment.

The roughening treatment is most commonly performed by depositing fine copper particles on the surface of the copper foil, and then covering and plating so that the fine copper particles do not fall off. That is, the formation of fine copper particles attached to the surface of the copper foil is performed by cathodic polarization of the copper foil itself and using the conditions of burnt copper plating. The burn copper plating conditions are not particularly limited, and are determined in consideration of the characteristics of the production line. For example, if a copper sulfate-based solution is used, the concentration is 5 to 20 g / l copper, 50 to 200 g / l sulfuric acid, and other additives (α-naphthoquinoline, dextrin, glue, thiourea, etc.), liquid For example, the temperature is 15 to 40 ° C. and the current density is 10 to 50 A / dm ² .

And, as the cover plating for preventing the fine copper particles from falling off, the copper is uniformly deposited so as to cover the fine copper particles under smooth plating conditions in order to prevent the fine copper particles deposited and deposited from falling off. is there. Accordingly, a copper electrolyte having a higher concentration than that used when depositing fine copper particles is used. The smooth plating conditions are not particularly limited and are determined in consideration of the characteristics of the production line. For example, if a copper sulfate-based solution is used, the conditions are copper 50 to 80 g / l, sulfuric acid 50 to 150 g / l, liquid temperature 40 to 50 ° C., and current density 10 to 50 A / dm ^2. .

Moreover, when the said covering plating is abbreviate | omitted, a very fine copper grain still finer than the said fine copper grain is adhered and formed. In general, a copper electrolyte containing arsenic is used to form the ultrafine copper particles. An example of electrolysis conditions in this case is a copper sulfate-based solution having a concentration of 10 g / l copper, 100 g / l sulfuric acid, 1.5 g / l arsenic, a liquid temperature of 38 ° C., and a current density of 30 A / dm ² . Etc. In order to avoid the use of arsenic, it is preferable to use a copper electrolyte added with 9-phenylacridine instead of arsenic. 9-Phenylacridine plays a role similar to the role played by arsenic in the field of copper electrolysis, and enables the sizing effect of precipitated fine copper grains and uniform electrodeposition. As a copper electrolyte for forming ultrafine copper grains to which 9-phenylacridine is added, the concentration is copper 5 to 10 g / l, sulfuric acid 100 to 120 g / l, 9-phenylacridine 50 to 300 mg / l, liquid temperature Electrolysis at a current density of 20 to 40 A / dm ² using 30 to 40 ° C. is preferable from the viewpoint of operational stability.

Regarding the method of forming the rust-proofing layer, no particular limitation is required in any case of forming the inorganic rust-proofing layer and the organic rust-proofing layer. A known technique and a known rust preventive component may be applied. However, in the case of an inorganic antirust treatment layer, a chromate layer may be further provided on the antirust layer of zinc, zinc alloy, nickel alloy or the like. For the formation of this chromate layer, it is suitable to employ an electrolytic chromate layer, and the electrolysis conditions at this time are not particularly limited, but chromic acid 1 to 7 g / l, liquid temperature 30 to 40 ° C. It is preferable to adopt conditions such as pH 10 to 12, current density 1 to 8 A / dm ² , electrolysis time 5 to 15 seconds, and the like.

Copper-clad laminate according to the present invention: The surface-treated copper foil provided with the silane coupling agent-treated layer according to the present invention described above is suitable as a printed wiring board material. In particular, when a copper foil that has not been subjected to roughening treatment is to be bonded to a resin base material, extremely good adhesion can be obtained.

  In addition, the resin base material said here is described as a concept including all resin base materials, such as a glass-epoxy base material, a glass-polyimide base material, a polyimide-type resin film base material, and an aramid resin film base material.

Production of surface-treated copper foil: In Example 1, a zinc-nickel alloy layer was formed as a rust-proofing layer on the glossy surface of an electrolytic copper foil having a thickness of 18 µm, and a chromate layer was formed on the surface. The conditions of the nickel-zinc alloy plating treatment at this time were as follows: nickel sulfate was used, the nickel concentration was 0.3 g / l, zinc pyrophosphate was used, the zinc concentration was 2.5 g / l, potassium pyrophosphate 100 g / l, the liquid temperature Electrolysis was performed under the conditions of 40 ° C., current density of 1 A / dm ² , and electrolysis time of 20 seconds to form a zinc-nickel alloy plating layer containing 70 wt% nickel and 30 wt% zinc. In the chromate treatment, a chromate layer was formed by electrolysis on the nickel-zinc alloy plating layer. The electrolysis conditions at this time were chromic acid 1.0 g / l, liquid temperature 35 ° C., current density 1 A / dm ² , and electrolysis time 5 seconds. A rust prevention treatment layer was formed as described above.

  And the silane coupling agent process layer was formed on the said antirust process layer using BTSPA. That is, BTSPA was added and dispersed in pure water so that the BTSPA concentration was 0.5 wt%, and adjusted to a solution pH of 3.0 to prepare a BTSPA-containing solution at room temperature. And this BTSPA containing solution was made to contact for 30 second on the antirust process layer of the said copper foil by showering.

  Subsequently, heat drying is performed under two conditions of 200 ° C. × 60 minutes and 250 ° C. × 60 minutes, and BTSPA adsorbed on the rust prevention treatment layer and the OH group on the copper foil surface (including the case where the rust prevention treatment layer is provided) And a condensation reaction between the bifunctional silane coupling agents were performed, and at the same time, the water generated as a result of the condensation was also completely evaporated to form a silane coupling agent-treated layer to obtain a surface-treated copper foil.

Manufacture of copper-clad laminate: The surface-treated copper foil obtained as described above is applied to a glass-epoxy prepreg (FR-4 substrate) having a thickness of 120 μm and a general vacuum press process at 180 ° C. for 60 minutes. Lamination was performed under conditions to obtain a copper clad laminate.

Manufacture of printed wiring board for peel strength measurement: An etching resist layer is formed on the copper foil surface of the copper-clad laminate using a dry film, the etching pattern is exposed, developed, and the resist is stripped. A linear circuit for measuring the peel strength was formed.

Measurement of peel strength: The peel strength here was measured at 10 points for each sample under each drying condition using the 90 ° peel test method defined in JIS. As a result, when the conditions of 200 ° C. × 60 minutes are adopted when forming the silane coupling agent treatment layer, the conditions of 0.57 to 0.60 kN / m and 250 ° C. × 60 minutes are adopted. It was 0.62 to 0.70 kN / m.

Production of surface-treated copper foil and the like: In Example 2, instead of BTSPA used in Example 1, BTSP-EDA was used, and the solution pH was adjusted to 5. Other conditions are the same as in the first embodiment. Further, in the same manner as in Example 1, a copper clad laminate was manufactured and a printed wiring board for peeling strength measurement was manufactured. Therefore, detailed description is omitted to avoid redundant description.

Measurement of peel strength: The peel strength here was measured in the same manner as in Example 1. As a result, when the conditions of 200 ° C. × 60 minutes are adopted when forming the silane coupling agent treatment layer, the conditions of 0.65 to 0.68 kN / m and 250 ° C. × 60 minutes are adopted. It was 0.69 to 0.72 kN / m.

Production of surface-treated copper foil, etc .: In this Example 2, the solution pH was adjusted to 3 using BTSE instead of BTSPA used in Example 1. Other conditions are the same as in the first embodiment. Further, in the same manner as in Example 1, a copper clad laminate was manufactured and a printed wiring board for peeling strength measurement was manufactured. Therefore, detailed description is omitted to avoid redundant description.

Measurement of peel strength: The peel strength here was measured in the same manner as in Example 1. As a result, when the conditions of 200 ° C. × 60 minutes are adopted when forming the silane coupling agent treatment layer, the conditions of 0.61 to 0.68 kN / m and 250 ° C. × 60 minutes are adopted. It was 0.66 to 0.71 kN / m.

Comparative example

[Comparative Example 1]
Production of surface-treated copper foil, etc .: In this comparative example, APS was used instead of BTSPA used in Example 1, and the solution pH was 10.4. Other conditions are the same as in the first embodiment. Further, in the same manner as in Example 1, a copper clad laminate was manufactured and a printed wiring board for peeling strength measurement was manufactured. Therefore, detailed description is omitted to avoid redundant description.

Measurement of peel strength: The peel strength here was measured in the same manner as in Example 1. As a result, when the conditions of 200 ° C. × 60 minutes are adopted when forming the silane coupling agent treatment layer, 0.50 to 0.55 kN / m when conditions of 250 ° C. × 60 minutes are adopted. It was 0.55 to 0.60 kN / m.

[Comparative Example 2]
Production of surface-treated copper foil, etc .: In this comparative example, BTSPA used in Example 1 was omitted. Therefore, no silane coupling agent was used. Other conditions are the same as in the first embodiment. Further, in the same manner as in Example 1, a copper clad laminate was manufactured and a printed wiring board for peeling strength measurement was manufactured. Therefore, detailed description is omitted to avoid redundant description.

Measurement of peel strength: The peel strength here was measured in the same manner as in Example 1. As a result, when conditions of 200 ° C. × 60 minutes are adopted when forming the silane coupling agent treatment layer, conditions of 0.18 kN / m to 0.25 kN / m, 250 ° C. × 60 minutes are adopted. Was 0.22 kN / m to 0.28 kN / m.

<Contrast between Example and Comparative Example>
The first to third embodiments described above are compared with the first comparative example. Comparative Example 1 employs a condition in which a silane coupling agent-treated layer in which APS is networked is formed using APS and the best adhesion is obtained. Nevertheless, the peel strength of each example clearly shows a larger value than the peel strength of the comparative example.

  And when Example 1-Example 3 and Comparative Example 2 are contrasted, it turns out that the difference in peeling strength appears remarkably depending on the presence or absence of the silane coupling agent treatment layer.

  The surface-treated copper foil which concerns on this invention is equipped with the silane coupling agent process layer formed using the bifunctional silane coupling agent on the adhesive surface with a resin base material. As a result, the adhesion between the surface-treated copper foil and the resin substrate is dramatically improved, and a stable adhesion to the resin substrate can be obtained even with a copper foil that is not subjected to a roughening treatment. Therefore, by using this surface-treated copper foil, it becomes possible to provide a copper-clad laminate having excellent adhesion between the copper foil and the resin base material, and further, a printed wiring obtained using the copper-clad laminate. This contributes to higher quality of the board.

  Also, when a silane coupling agent-treated layer is formed using the above bifunctional silane coupling agent, it does not require special equipment and can be produced using conventional equipment. is there. Therefore, the manufacturing method of the surface treatment copper foil which concerns on this invention is a manufacturing method which can draw out the characteristic of the silane coupling agent processing layer formed using a bifunctional silane coupling agent on the copper foil surface to the maximum. Excellent economy.

It is the depth profile of each element which comprises the silane coupling agent process layer of the surface treatment copper foil measured using rf-GDOES. It is an adsorption model on the surface of copper foil when APS is used as a silane coupling agent. It is the figure which showed the relationship between the solution pH of a BTSPA containing solution, and peeling strength. It is the figure which showed the relationship between the solution pH of a BTSP-EDA containing solution, and peeling strength. It is the figure which showed the relationship between the solution pH of BTSE containing solution, and peeling strength.

Claims (12)

A surface-treated copper foil provided with a silane coupling agent-treated layer on the adhesive surface with the resin base layer of the copper foil,
The silane coupling agent treatment layer surface treated copper foil, characterized in that formed using a bifunctional silane coupling agent having a functional group -Si (OCH ₃₎ at both ends of formula. The surface-treated copper foil according to claim 1, wherein the bifunctional silane coupling agent has a basic structure shown as Chemical Formula 1 below.

The bifunctional silane coupling agent is a bis-γ-trimethoxysilylpropylamine having n = 3 and m = 1 and having a basic structure represented by the following chemical formula 2. Surface treated copper foil.

3. The bifunctional silane coupling agent is a bis-γ-trimethoxysilylpropylethylenediamine having n = 4 and m = 2 and having a basic structure represented by the following chemical formula 3. Surface treated copper foil.

The bifunctional silane coupling agent is bis-γ-trimethoxysilylethane of n = 1 and m = 0, and has a basic structure shown as the following chemical formula 4. Surface treated copper foil.

It is a manufacturing method of the surface treatment copper foil which formed the silane coupling agent processing layer on the copper foil surface using the bifunctional silane coupling agent in any one of Claims 1-5,
Preparing a bifunctional silane coupling agent-containing solution in which the bifunctional silane coupling agent is dispersed in a solvent;
The bifunctional silane coupling agent-containing solution and the copper foil surface are brought into contact with each other, and a bifunctional silane coupling agent adsorption layer is formed on the adhesive surface of the copper foil.
Then, the manufacturing method of the surface treatment copper foil provided with the silane coupling agent processing layer characterized by drying for 10 second-60 minutes in a heating atmosphere of 190 to 270 degreeC, and forming a silane coupling agent processing layer . The silane coupling agent treatment according to claim 6, wherein the bifunctional silane coupling agent-containing solution is prepared by dispersing bis-γ-trimethoxysilylpropylamine in a solvent to a pH of 3.0 to 5.0. The manufacturing method of the surface treatment copper foil provided with a layer. The silane coupling agent treatment according to claim 6, wherein the bifunctional silane coupling agent-containing solution is prepared by dispersing bis-γ-trimethoxysilylpropylethylenediamine in a solvent to a pH of 4.5 to 11.5. The manufacturing method of the surface treatment copper foil provided with a layer. The bifunctional silane coupling agent-containing solution is prepared by dispersing bis-γ-trimethoxysilylethane in a solvent in a pH range of pH 3.0 to pH 6.0 or pH 11.0 or higher. Item 7. A method for producing a surface-treated copper foil comprising the silane coupling agent-treated layer according to Item 6. The surface-treated copper foil provided with the silane coupling agent process layer in any one of Claims 6-9 which uses what gave the roughening process and / or the antirust process to the said copper foil. Manufacturing method. The method for producing a surface-treated copper foil provided with the silane coupling agent-treated layer according to claim 10, wherein the rust prevention treatment is an inorganic rust prevention treatment or an organic rust prevention treatment. The copper clad laminated board obtained using a surface-treated copper foil provided with the silane coupling agent process layer in any one of Claims 6-9.

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