CN119546801A - Surface treatment of copper foil, copper clad laminates and printed circuit boards - Google Patents
Surface treatment of copper foil, copper clad laminates and printed circuit boards Download PDFInfo
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- CN119546801A CN119546801A CN202380053761.0A CN202380053761A CN119546801A CN 119546801 A CN119546801 A CN 119546801A CN 202380053761 A CN202380053761 A CN 202380053761A CN 119546801 A CN119546801 A CN 119546801A
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- copper foil
- heteroaromatic compound
- treated copper
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/38—Improvement of the adhesion between the insulating substrate and the metal
- H05K3/382—Improvement of the adhesion between the insulating substrate and the metal by special treatment of the metal
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C26/00—Coating not provided for in groups C23C2/00 - C23C24/00
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/38—Improvement of the adhesion between the insulating substrate and the metal
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- Microelectronics & Electronic Packaging (AREA)
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- Other Surface Treatments For Metallic Materials (AREA)
Abstract
The present invention relates to a surface-treated copper foil comprising a copper foil and a heteroaromatic compound layer formed on at least one surface of the copper foil. The heteroaromatic compound layer contains a heteroaromatic compound having a heterocycle containing a nitrogen atom as a heteroatom, and Ssk is-2.00 to-0.10.
Description
Technical Field
The invention relates to a surface-treated copper foil, a copper-clad laminate and a printed wiring board.
Background
Copper-clad laminates are widely used in various applications such as flexible printed wiring boards. The flexible printed wiring board is manufactured by etching a copper foil of a copper-clad laminate to form a conductor pattern (also referred to as a "wiring pattern"), and connecting electronic parts to the conductor pattern by solder to assemble the electronic parts.
In recent years, with the increase in communication speed and capacity in electronic devices such as personal computers and mobile terminals, there has been a demand for flexible printed wiring boards capable of accommodating such electronic devices as electric signals at higher frequencies. In particular, the higher the frequency of the electric signal, the greater the loss (attenuation) of the signal power, and the easier it is to read data, and therefore, it is required to reduce the loss of the signal power.
The reasons for generating signal power loss (transmission loss) in an electronic circuit can be largely divided into two types. One is conductor loss, i.e., loss caused by copper foil, and the other is dielectric loss, i.e., loss caused by resin base material.
The conductor loss has a characteristic that it has a skin effect in a high frequency band and a current flows on the surface of the conductor, so that if the surface of the copper foil is roughened, the current flows along a complicated path. Therefore, in order to reduce the conductor loss of the high-frequency signal, it is desirable to reduce the surface roughness of the copper foil. Hereinafter, in the present specification, when only "transmission loss" and "conductor loss" are described, the "transmission loss of a high-frequency signal" and "conductor loss of a high-frequency signal" are mainly meant.
Since dielectric loss depends on the type of resin base material, it is preferable to use a resin base material made of a low dielectric material (e.g., a liquid crystal polymer or a low dielectric polyimide) for a circuit board in which a high frequency signal flows.
In order to ensure adhesion between the copper foil and the resin base material, a surface treatment layer containing roughened particles is proposed to be formed on at least one surface of the copper foil. The purpose of the method is to improve adhesion by utilizing anchor effect of coarsening particles immersed in a resin substrate. For example, patent document 1 proposes a method in which a roughened layer formed of roughened particles is provided on a copper foil, and an anti-rust treatment layer is formed thereon. The rust-proof treatment layer is composed of a nickel-cobalt alloy plating layer, a galvanized layer, a chromate treatment layer and a silane coupling treatment layer.
Background art literature
Patent literature
Patent document 1 Japanese patent application laid-open No. 2012-112009
Disclosure of Invention
Problems to be solved by the invention
The surface-treated copper foil described in patent document 1 has a problem in that the time and cost required for manufacturing the copper foil increase because a large number of layers must be formed on the copper foil. In addition, in the resin base material, particularly in the low dielectric material, sufficient adhesion may not be ensured by the anchor effect of the coarsening particles.
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a surface-treated copper foil which can suppress the time and cost required for production and can improve adhesion to a resin substrate, particularly a resin substrate suitable for high-frequency applications.
In addition, in another aspect, an object of the present invention is to provide a copper-clad laminate which is excellent in adhesion between a resin base material, particularly a resin base material suitable for high-frequency applications, and a surface-treated copper foil, while suppressing the time and cost required for production.
In addition, in another aspect, an object of the present invention is to provide a printed wiring board which is excellent in adhesion between a resin base material, particularly a resin base material suitable for high-frequency applications, and a circuit pattern, while suppressing the time and cost required for manufacturing.
Technical means for solving the problems
The inventors of the present invention have made intensive studies to solve the above problems, and as a result, have surprisingly found that a specific heteroaromatic compound has a function of improving adhesion to a resin base material. Based on this finding, it was found that the above problems can be solved by forming a heteroaromatic compound layer containing a specific heteroaromatic compound on at least one surface of a copper foil and controlling Ssk on the surface thereof within a predetermined range, and thus an embodiment of the present invention was completed.
That is, in one aspect, an embodiment of the present invention relates to a surface-treated copper foil comprising a copper foil, and a heteroaromatic compound layer formed on at least one surface of the copper foil, wherein the heteroaromatic compound layer contains a heteroaromatic compound having a heterocyclic ring containing a nitrogen atom as a heteroatom, and Ssk is from-2.00 to-0.10.
In another aspect, an embodiment of the present invention relates to a copper-clad laminate comprising the surface-treated copper foil and the resin substrate of the heteroaromatic compound layer attached to the surface-treated copper foil.
In another aspect, an embodiment of the present invention relates to a printed wiring board including a circuit pattern formed by etching the surface-treated copper foil of the copper-clad laminate.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the embodiments of the present invention, in one aspect, a surface-treated copper foil can be provided that can suppress the time and cost required for production and improve adhesion to a resin substrate, particularly a resin substrate suitable for high-frequency applications.
Further, according to the embodiment of the present invention, in another aspect, a copper-clad laminate which is excellent in adhesion between a resin base material, particularly a resin base material suitable for high-frequency applications, and a surface-treated copper foil, while suppressing the time and cost required for production, can be provided.
Further, according to the embodiment of the present invention, in another aspect, a printed wiring board can be provided in which time and cost required for manufacturing are suppressed and adhesion between a resin base material, particularly, a resin base material suitable for high frequency use and a circuit pattern is excellent.
Drawings
FIG. 1 is an example of a load curve of a heteroaromatic compound layer.
Detailed Description
The preferred embodiments of the present invention will be specifically described below, but the present invention should not be construed as limited thereto, and various changes, modifications and the like may be made based on the knowledge of those skilled in the art without departing from the gist of the present invention. The plurality of constituent elements disclosed in the following embodiments may be combined appropriately to form various inventions. For example, some of the constituent elements may be deleted from all the constituent elements disclosed in the following embodiments, and constituent elements of different embodiments may be appropriately combined.
The surface-treated copper foil of the embodiment of the present invention has a copper foil, and a heteroaromatic compound layer formed on at least one surface of the copper foil.
The heteroaromatic compound layer may be formed on only one surface of the copper foil, or may be formed on both surfaces of the copper foil. In the case of forming the heteroaromatic compound layer on both surfaces of the copper foil, the types of the heteroaromatic compound layers may be the same or different.
The copper foil is not particularly limited, and may be either an electrolytic copper foil or a rolled copper foil.
As a material of the copper foil, high purity copper such as refined copper (JIS H3100 alloy No. C1100) and oxygen-free copper (JIS H3100 alloy No. C1020 or JIS H3510 alloy No. C1011) which are generally used as a circuit pattern of a printed wiring board can be used. For example, copper alloys such as Sn-doped copper, ag-doped copper, copper alloys containing Cr, zr, mg, or the like, and copper alloys of casson system containing Ni, si, or the like may be used. In the present specification, the term "copper foil" also includes a concept of copper alloy foil.
The thickness of the copper foil is not particularly limited, and may be, for example, 1 to 1000 μm or 1 to 500 μm or 1 to 300 μm or 3 to 100 μm or 5 to 70 μm or 6 to 35 μm or 9 to 18 μm.
The heteroaromatic compound layer contains a heteroaromatic compound having a heterocycle containing a nitrogen atom as a heteroatom.
The number of ring members of the heterocycle is not particularly limited, and is, for example, 3 to 9, preferably 4 to 6, and more preferably 5.
The hetero atom contained in the heterocycle may be constituted by only a nitrogen atom, or may be constituted by a nitrogen atom and an atom other than the nitrogen atom (for example, an oxygen atom, a sulfur atom, or the like).
The number of hetero atoms contained in the heterocycle depends on the number of ring members, and is, for example, 1 to 5, preferably 1 to 4, and more preferably 1 to 3.
The heterocyclic ring may be any of a saturated ring and an unsaturated ring. Here, the term unsaturated ring is a concept including a partially unsaturated ring.
Specific examples of the heterocyclic ring include acridine (unsaturated 3-membered ring having 1 nitrogen atom), diazo sucking (unsaturated 3-membered ring having 2 nitrogen atoms), az (unsaturated 4-membered ring having 1 nitrogen atom), diaza (unsaturated 4-membered ring having 2 nitrogen atoms), pyrrole (unsaturated 5-membered ring having 1 nitrogen atom), pyrrolidine (saturated 5-membered ring having 1 nitrogen atom), imidazole and pyrazole (unsaturated 5-membered ring having 2 nitrogen atoms), imidazolidine and pyrazolidine (saturated 5-membered ring having 2 nitrogen atoms), oxazole and isoxazole (unsaturated 5-membered ring having 1 nitrogen atom and 1 oxygen atom), Oxazolidines and isoxazolidines (saturated 5-membered rings containing 1 nitrogen atom and 1 oxygen atom), thiazoles and isothiazoles (unsaturated 5-membered rings containing 1 nitrogen atom and 1 sulfur atom), thiazoles and isothiazoles (saturated 5-membered rings containing 1 nitrogen atom and 1 oxygen atom), triazoles such as 1,2, 3-triazole or 1,2, 4-triazole (unsaturated 5-membered rings containing 3 nitrogen atoms), tetrazoles (unsaturated 5-membered rings containing 4 nitrogen atoms), tetrazoles (unsaturated 5-membered rings containing 5 nitrogen atoms), furazanes and oxadiazoles (unsaturated 5-membered rings containing 2 nitrogen atoms and 1 oxygen atom), thiadiazoles (unsaturated 5-membered rings containing 2 nitrogen atoms and 1 sulfur atom), triazoles such as thiadiazoles, Dioxazole (unsaturated 5-membered ring containing 1 nitrogen atom and 2 oxygen atoms), dithiazole (unsaturated 5-membered ring containing 1 nitrogen atom and 2 sulfur atoms), oxatetrazole (unsaturated 5-membered ring containing 4 nitrogen atoms and 1 oxygen atom), thiatetrazole (unsaturated 5-membered ring containing 4 nitrogen atoms and 1 sulfur atom), pyridine (unsaturated 6-membered ring containing 1 nitrogen atom), piperidine (saturated 6-membered ring containing 1 nitrogen atom), diazine (unsaturated 6-membered ring containing 2 nitrogen atoms), piperazine (saturated 6-membered ring containing 2 nitrogen atoms), oxazine (unsaturated 6-membered ring containing 1 nitrogen atom and 1 oxygen atom), oxazine, In (saturated 6-membered ring containing 1 nitrogen atom and 1 oxygen atom), thiazine (unsaturated 6-membered ring containing 1 nitrogen atom and 1 sulfur atom), thiolin (saturated 6-membered ring containing 1 nitrogen atom and 1 sulfur atom), triazine (unsaturated 6-membered ring containing 3 nitrogen atoms), tetrazine (unsaturated 6-membered ring containing 4 nitrogen atoms), pentazine (unsaturated 6-membered ring containing 5 nitrogen atoms), nitrogen hydride (unsaturated 7-membered ring containing 1 nitrogen atom), azepane (ALA) (saturated 7-membered ring containing 1 nitrogen atom), diazane (unsaturated 7-membered ring containing 2 nitrogen atoms), diazacycloheptane (saturated 7-membered ring containing 2 nitrogen atoms), pentazine (saturated 7-membered ring containing 2 nitrogen atoms), Azocyclooctatetraene (unsaturated 8-membered ring containing 1 nitrogen atom), azacyclooctane (saturated 8-membered ring containing 1 nitrogen atom), azonine (unsaturated 9-membered ring containing 1 nitrogen atom), azacyclononane (saturated 9-membered ring containing 1 nitrogen atom), and the like. among these, the heterocycle is preferably a 5-membered ring containing 1 to 3 nitrogen atoms, more preferably an unsaturated 5-membered ring containing 1 to 3 nitrogen atoms (pyrrole, imidazole, pyrazole, oxazole, isoxazole, thiazole, isothiazole, triazole) from the viewpoint of stably improving the adhesion to the resin substrate.
The heteroaromatic compound having a heterocycle may be a condensed cyclic compound of a benzene ring and a heterocycle, a condensed cyclic compound of 2 or more heterocycles, or a heterocyclic monocyclic compound.
Examples of the condensed cyclic compound of the benzene ring and the heterocyclic ring include, but are not particularly limited to, indole, indazole, isoindole, benzimidazole, benzotriazole, quinoline, isoquinoline, quinazoline, quinoxaline, cinnoline, acridine, carbazole, and the like.
Examples of the condensed ring compound having 2 or more heterocyclic rings include, but are not particularly limited to, triazolopyridines, purines, pteridines, and the like.
The heterocyclic monocyclic compound is not particularly limited, and examples thereof include the compounds exemplified above as heterocyclic rings.
The condensed cyclic compound and the monocyclic compound may have a substituent. The substituent is not particularly limited. Examples of the substituent include an alkyl group such as a methyl group or an ethyl group, a vinyl group, a nitro group, and the like.
The heteroaromatic compound layer is a layer containing the heteroaromatic compound.
The heteroaromatic compound contained in the heteroaromatic compound layer may be a single type or may be different from 2 or more types.
The heteroaromatic compound layer may contain components other than the heteroaromatic compound within a range that does not impair the effect achieved in the embodiment of the present invention. Examples of the component include a solvent and an additive to be mixed in forming the heteroaromatic compound layer.
Compared with the conventional surface treatment layer containing the roughened layer, the heteroaromatic compound layer has fewer peaks. That is, the smoothness of the heteroaromatic compound layer is high. The reason for this is that the conventional surface-treated layer including the roughened layer improves adhesion between the surface-treated layer and the resin base material by the anchor effect, and the heteroaromatic compound layer is not intended to obtain the adhesion improving effect by the anchor effect. That is, the adhesion between the surface-treated copper foil and the resin base material is improved by the adhesion property of the heteroaromatic compound, so that a desired adhesion improving effect can be obtained even if the number of peaks and valleys on the surface is small. Further, the heteroaromatic compound layer has higher smoothness than the conventional surface-treated layer including the roughened layer, and therefore, can reduce transmission loss due to skin effect.
As one of the indices indicating the smoothness of the surface, ssk (skew) which is an index indicating the distribution of the peaks and valleys of the surface can be used. Ssk is a parameter in the height direction specified by ISO 25178-2:2012, and represents symmetry of peaks and valleys with respect to the average surface of the surface. When Ssk is 0, the peaks and valleys are symmetrically distributed. If Ssk is greater than 0, it means that the peak portion of the surface is greater than the valley portion, and if Ssk is less than 0, it means that the valley portion of the surface is greater than the peak portion.
The Ssk of the heteroaromatic compound layer is-2.00 to-0.10. That is, the surface of the heteroaromatic compound layer has more valleys than peaks. Since the surface-treated layer containing the roughened layer has a large number of peaks, the surface of the heteroaromatic compound layer is highly smooth. Since Ssk controls the smoothness of the heteroaromatic compound layer in such a range, the effect of improving the adhesion between the surface-treated copper foil and the resin base material due to the adhesion property of the heteroaromatic compound can be obtained. In addition, the effect of reducing transmission loss can be obtained.
From the viewpoint of stably obtaining the above-mentioned effects, ssk of the heteroaromatic compound layer is preferably-2.00 to-0.50, more preferably-2.00 to-0.80, and still more preferably-1.50 to-0.80.
Furthermore, ssk of the heteroaromatic layer may be determined in accordance with ISO 25178-2:2012.
Compared with the conventional surface-treated layer including the roughened layer, the heteroaromatic compound layer has few peaks on the surface because no roughened particles are present. As an index indicating the proportion of peaks on the surface of the heteroaromatic compound layer, vmp (the volume of the solid portion of the peak) can be used. Vmp is a functional (volume) parameter specified by ISO 25178-2:2012, and represents the solid volume of the peak of the heteroaromatic compound layer.
Vmp can be measured by measuring surface roughness according to ISO 25178-2:2012 and analyzing a load curve calculated from the measured data.
In describing the load curve, the load area ratio will be described first.
The load area ratio is a ratio obtained by dividing the area of the cross section of the measurement object corresponding to the case where the three-dimensional measurement object is cut off at a certain height plane by the area of the measurement field of view. In the present invention, a copper foil, a heteroaromatic compound layer of a surface-treated copper foil, or the like is assumed as a measurement object. The load curve is a curve representing the load area ratio at each height. The vicinity of the load area ratio of 0% represents the height of the highest portion of the object to be measured, and the vicinity of the load area ratio of 100% represents the height of the lowest portion of the object to be measured.
An example of a load curve is then disclosed in fig. 1. The solid part volume and the space part volume of the heteroaromatic compound layer can be expressed by using the load curve flexibly. The solid volume corresponds to the volume of the portion of the measurement object that occupies the solid in the measurement field of view, and the space volume corresponds to the volume of the space between the solid portions in the measurement field of view. In the load curve, the load area ratio is divided into a valley portion, a core portion, and a peak portion at the boundary between the positions of 10% and 80%. If the heteroaromatic compound layer according to the embodiment of the present invention is described with reference to fig. 1, vvv means the space volume of the valley portion of the heteroaromatic compound layer, vvc means the space volume of the core portion of the heteroaromatic compound layer, vmp means the solid volume of the peak portion of the heteroaromatic compound layer, and Vmc means the solid volume of the core portion of the heteroaromatic compound layer.
The peak is a portion of the object to be measured having a high height. The valley is a portion of the object to be measured having a low height. The core portion is a portion other than the peak portion and the valley portion in the object to be measured, that is, a portion close to the average height.
The solid portion volume Vmp of the peak is the solid portion volume of the peak, i.e., the portion of the object to be measured having a high height, and means the solid portion volume of the portion of the heteroaromatic compound layer having a particularly high height.
The Vmp of the heteroaromatic compound layer is preferably 0.001 to 0.010 μm 3/μm2, more preferably 0.001 to 0.006 μm 3/μm2. The range of Vmp, which is the volume of the solid portion of the portion having a particularly high height, is such a range, meaning that the heteroaromatic compound layer is smooth. Further, by controlling Vmp in such a range, the adhesion improving effect between the surface-treated copper foil and the resin base material due to the adhesion property of the heteroaromatic compound can be obtained. In addition, the effect of reducing transmission loss can be obtained.
Furthermore, the Vmp of the heteroaromatic layer may be determined in accordance with ISO 25178-2:2012.
The heteroaromatic compound layer is smoother than the conventional surface-treated layer including the roughened layer because no roughened particles are present. The valleys on the surface of the heteroaromatic compound layer are also shallower. As an index indicating the depth of the valley, sv (maximum valley depth of the valley) can be used. Sv is a height parameter specified by ISO 25178-2:2012, and represents the minimum value of the height from the average surface of the heteroaromatic layer surface.
The Sv of the heteroaromatic compound layer is preferably 1.50 μm or less, more preferably 0.10 to 1.25 μm, and still more preferably 0.50 to 1.20 μm. By controlling Sv in such a range, the adhesion improving effect between the surface-treated copper foil and the resin base material due to the adhesion property of the heteroaromatic compound can be obtained. In addition, the effect of reducing transmission loss can be obtained.
Furthermore, the Sv of the heteroaromatic layer may be determined in accordance with ISO 25178-2:2012.
The surface-treated copper foil of the embodiment of the present invention is preferably a copper foil in direct contact with the heteroaromatic compound layer, but a functional layer may be provided between the copper foil and the heteroaromatic compound layer within a range that does not impair the effect of the embodiment of the present invention. Examples of the functional layer include a heat-resistant layer, a rust-preventive layer, and a chromate layer.
The method for producing the surface-treated copper foil according to the embodiment of the present invention is not particularly limited, and the surface-treated copper foil can be produced by, for example, the following method.
First, a copper foil is manufactured by a method well known in the art. For example, in the case of using an electrolytic copper foil as a copper foil, in general, it can be manufactured by electrodepositing copper from a copper sulfate plating bath onto a drum of titanium or stainless steel. In the case of using a rolled copper foil as a copper foil, it is generally produced by sequentially subjecting a copper ingot to homogenizing annealing, hot rolling, cold rolling, annealing, and the like. Alternatively, since a copper foil is commercially available, a commercially available product can be used. However, in the case of using a commercially available copper foil, an anti-rust agent, oil, or the like may adhere to the surface of the copper foil, and thus the copper foil may be degreased and pickled. This is because, if various surface treatment layers are formed on the surface of the copper foil, it is difficult to form a heteroaromatic compound layer on the surface of the copper foil.
Then, a coating liquid of a heteroaromatic compound is prepared. The coating liquid may contain a solvent such as water, an additive, or the like. The concentration of the heteroaromatic compound in the coating liquid may be adjusted according to the type of heteroaromatic compound used, and is not particularly limited, and is, for example, 0.1 to 10 mass%.
Then, the coating liquid of the heteroaromatic compound is applied to the surface of the copper foil and dried, thereby forming a heteroaromatic compound layer. The coating method is not particularly limited, and various methods such as dipping, spraying, curtain coating, flat coater coating, roll coater coating, brush coating, and roller brush coating can be used. The drying method is not particularly limited, and may be normal temperature drying or heat drying depending on the type of solvent used. The coating and drying of the coating liquid of the heteroaromatic compound may be performed 1 time, but may be performed several times to form a heteroaromatic compound layer of a desired thickness.
The Ssk, vmp, and Sv of the heteroaromatic compound layer can be controlled mainly by adjusting the surface roughness of the copper foil on which the heteroaromatic compound layer is formed. The roughness of the copper foil can be controlled by adjusting the production conditions of the copper foil, degreasing conditions before formation of the heteroaromatic compound layer, acid cleaning conditions, and the like.
The surface-treated copper foil of the embodiment of the present invention has a heteroaromatic compound layer containing a specific heteroaromatic compound, and the Ssk of the heteroaromatic compound layer is controlled to be-2.00 to-0.10, so that the time and cost required for production can be suppressed, and the adhesion to a resin base material, particularly a resin base material suitable for high-frequency applications, can be improved.
The copper-clad laminate of the embodiment of the present invention comprises the surface-treated copper foil, and a resin substrate having a heteroaromatic compound layer adhered to the surface-treated copper foil.
The copper-clad laminate can be produced by bonding a resin substrate to the surface-treated copper foil layer of the heteroaromatic compound.
The resin base material is not particularly limited, and any known resin base material in the art can be used. Examples of the resin substrate include paper substrate phenol resin, paper substrate epoxy resin, synthetic fiber cloth substrate epoxy resin, glass cloth-paper composite substrate epoxy resin, glass cloth-glass non-woven cloth composite substrate epoxy resin, glass cloth substrate epoxy resin, polyester film, polyimide resin, liquid crystal polymer, and fluororesin. Of these, the resin base material is preferably polyimide resin. The resin base material may be formed of a low dielectric material. Examples of the low dielectric material include a liquid crystal polymer and a low dielectric polyimide.
The method for bonding the surface-treated copper foil to the resin base material is not particularly limited, and may be carried out according to a method known in the art. For example, the surface-treated copper foil and the resin-based material layer may be laminated and thermally bonded.
The copper-clad laminate manufactured in the above manner can be used for manufacturing a printed wiring board.
The copper-clad laminate according to the embodiment of the present invention uses the surface-treated copper foil, and therefore, the time and cost required for production can be reduced, and the adhesion between the resin base material, particularly, a resin base material suitable for high-frequency applications, and the surface-treated copper foil can be improved.
The printed wiring board according to the embodiment of the present invention includes a circuit pattern formed by etching the surface-treated copper foil of the copper-clad laminate.
The printed wiring board can be manufactured by etching the surface-treated copper foil of the copper-clad laminate to form a circuit pattern. The method for forming the circuit pattern is not particularly limited, and known methods such as a subtractive method and a semi-additive method can be used. Among them, the formation method of the circuit pattern is preferably a subtractive method.
In the case of manufacturing a printed wiring board by the subtractive method, it is preferable to proceed as follows. First, a resist is applied to the surface of a surface-treated copper foil of a copper-clad laminate, and the surface is exposed to light and developed to form a predetermined resist pattern. Then, the surface-treated copper foil is etched to remove a portion (unnecessary portion) where the resist pattern is not formed, thereby forming a circuit pattern. Finally, the resist pattern on the surface treated copper foil is removed.
The conditions in the reduction method are not particularly limited, and may be performed according to conditions known in the art.
Since the copper-clad laminate is used in the printed wiring board according to the embodiment of the present invention, the time and cost required for manufacturing can be reduced, and the adhesion between the resin base material, particularly, a resin base material suitable for high-frequency use, and the circuit pattern can be improved.
Examples (example)
Hereinafter, embodiments of the present invention will be further specifically described by way of examples, but the present invention is not limited to these examples.
Example 1
A commercially available rolled copper foil (HA-V2; thickness 12 μm, manufactured by JX Metal Co., ltd.) was prepared as a copper foil, and both sides of the copper foil were degreased and pickled. Degreasing was performed by electrolyzing the surface of the rolled copper foil in an aqueous solution of 20g/L GN cleaning solution 87 (JX Metal Co., ltd.) at a current density of 11.3A/dm 2 for 8.6 seconds. The pickling is performed by immersing in an aqueous solution of sulfuric acid of 20g/L for 30 seconds.
Then, an aqueous solution (coating liquid) of benzotriazole was prepared using benzotriazole represented by the following formula (1) as a heteroaromatic compound. The concentration of benzotriazole in the aqueous solution was set to 1 mass%.
Then, the copper foil was immersed in an aqueous solution of benzotriazole for 30 seconds, and then washed with water, and dried by a dryer. In this way, a surface-treated copper foil having a benzotriazole layer (heteroaromatic compound layer) formed on the surface of the copper foil was obtained.
Example 2
A surface-treated copper foil having an indazole layer (heteroaromatic compound layer) formed on the surface of the copper foil was obtained under the same conditions as in example 1, except that an indazole represented by the following formula (2) was used as the heteroaromatic compound.
Example 3
A surface-treated copper foil having a benzimidazole layer (heteroaromatic compound layer) formed on the surface of the copper foil was obtained under the same conditions as in example 1, except that benzimidazole represented by the following formula (3) was used as the heteroaromatic compound.
Example 4
A surface-treated copper foil having an indole layer (heteroaromatic compound layer) formed on the surface of the copper foil was obtained under the same conditions as in example 1, except that indole represented by the following formula (4) was used as the heteroaromatic compound.
Example 5
A surface-treated copper foil having a triazolopyridine layer (heteroaromatic compound layer) formed on the surface of the copper foil was obtained under the same conditions as in example 1, except that triazolopyridine represented by the following formula (5) was used as the heteroaromatic compound.
Example 6
A surface-treated copper foil having a 1-methylbenzotriazole layer (heteroaromatic compound layer) formed on the surface of the copper foil was obtained under the same conditions as in example 1, except that 1-methylbenzotriazole represented by the following formula (6) was used as the heteroaromatic compound.
Example 7
A surface-treated copper foil having a 5-methylbenzotriazole layer (heteroaromatic layer) formed on the surface of the copper foil was obtained under the same conditions as in example 1, except that 5-methylbenzotriazole represented by the following formula (7) was used as the heteroaromatic compound.
Example 8
A surface-treated copper foil having a1, 2, 3-triazole layer (heteroaromatic compound layer) formed on the surface of the copper foil was obtained under the same conditions as in example 1, except that 1,2, 3-triazole represented by the following formula (8) was used as the heteroaromatic compound.
Comparative example 1
A commercially available rolled copper foil (HA-V2 manufactured by JX Metal Co., ltd.; copper foil having both sides degreased and pickled (copper foil having no heteroaromatic layer formed thereon) was used as a comparative sample. Degreasing and pickling were performed under the same conditions as in example 1.
Comparative example 2
Both surfaces of a commercially available rolled copper foil (HA-V2; thickness 12 μm, manufactured by JX Metal Co., ltd.) were degreased and pickled under the same conditions as in example 1.
Then, a roughened layer, a rust-preventive layer and a silane coupling layer are sequentially formed on the surface of the copper foil, thereby obtaining a surface-treated copper foil. The conditions for forming the layers are as follows.
< Roughened layer >
The roughened layer is formed by electroplating. Electroplating was performed in 3 stages. Further, the plating solution composition and the current density are basically values obtained by rounding the first digit after the decimal point.
(Conditions of stage 1)
Plating solution composition of 11g/L Cu and 50g/L sulfuric acid
Plating solution temperature of 27 DEG C
Electroplating conditions, current density 40A/dm 2, time 1.4 seconds
(Conditions of stage 2)
Plating solution composition of 20g/L Cu and 100g/L sulfuric acid
Plating solution temperature of 50 DEG C
Electroplating conditions, current density 5A/dm 2, time 2.0 seconds
(Conditions of stage 3)
Plating solution composition of 16g/L Cu, 8g/L Co and 10g/L Ni
Plating solution pH 2.4
Plating solution temperature of 36 DEG C
Electroplating conditions, current density 32A/dm 2, time 0.2 seconds
< Antirust layer >
The rust preventive layer is formed by electroplating. Electroplating was performed in 3 stages.
(Conditions of stage 1)
Plating solution composition of 3g/L Co and 13g/L Ni
Plating solution pH 2.0
Plating solution temperature of 50 DEG C
Electroplating conditions, current density 2A/dm 2, time 0.8 seconds
(Conditions of stage 2)
Plating solution composition of 5g/L Zn, 24g/L Ni
Plating solution pH 3.6
Plating solution temperature of 40 DEG C
Electroplating conditions, current density 4A/dm 2, time 0.4 seconds
(Conditions of stage 3)
Plating solution composition of 3g/L K 2Cr2O7 and 0.3g/L Zn
Plating solution pH 3.7
Plating solution temperature of 55 DEG C
Electroplating conditions, current density 3A/dm 2, time 0.8 seconds
< Silane coupling treatment layer >
A4.0% by volume aqueous solution (pH: 10.4) of N-2- (aminoethyl) -3-aminopropyl trimethoxysilane (KBM 603 manufactured by Xinyue chemical Co., ltd.) was applied and dried, whereby a silane coupling layer was formed.
Comparative example 3
Both surfaces of a commercially available rolled copper foil (HA-V2; thickness 12 μm, manufactured by JX Metal Co., ltd.) were degreased and pickled under the same conditions as in example 1.
Then, a roughened layer, a heat-resistant layer, a chromate layer and a silane coupling layer were sequentially formed on the surface of the copper foil, thereby obtaining a surface-treated copper foil. The conditions for forming the layers are as follows.
< Roughened layer >
The roughened layer is formed by electroplating. Electroplating was performed in 2 stages.
(Conditions of stage 1)
Plating solution composition of 11g/L Cu and 50g/L sulfuric acid
Plating solution temperature 25 DEG C
Electroplating conditions, current density of 42.7A/dm 2, time of 1.4 seconds
(Conditions of stage 2)
Plating solution composition of 20g/L Cu and 100g/L sulfuric acid
Plating solution temperature of 50 DEG C
Electroplating conditions, current density of 3.8A/dm 2, time of 2.8 seconds
< Heat-resistant layer >
The heat-resistant layer is formed by electroplating.
Plating solution composition of 23.5g/L Ni and 4.5g/L Zn
Plating solution pH 3.6
Plating solution temperature of 40 DEG C
Electroplating conditions, current density of 1.1A/dm 2, time of 0.7 seconds
< Chromate treatment layer >
The chromate treatment layer is formed by electroplating.
Plating solution composition of 3.0g/L K 2Cr2O7 and 0.33g/L Zn
Plating solution pH 3.6
Plating solution temperature of 50 DEG C
Electroplating conditions, current density of 2.1A/dm 2, time of 1.4 seconds
< Silane coupling treatment layer >
A1.2% by volume aqueous solution (pH: 10) of N-2- (aminoethyl) -3-aminopropyl trimethoxysilane (KBM 603 manufactured by Xinyue chemical Co., ltd.) was applied and dried, whereby a silane coupling layer was formed.
The surface-treated copper foil or copper foil obtained in the above examples and comparative examples was subjected to the following characteristic evaluation.
< Ssk, vmp, and Sv >
Image capturing was performed using a laser microscope (LEXT OLS 4000) manufactured by olympus corporation. Analysis of the captured image was performed using analysis software of a laser microscope (LEXT OLS 4100) manufactured by olympus corporation. Ssk, vmp and Sv are measured according to ISO 25178-2:2012, respectively. Further, as to the measurement results of these, the average value of the values measured at any 3 points was taken as the measurement result. The temperature at the time of measurement is set to 23-25 ℃. The main setting conditions in the laser microscope and analysis software are as follows.
Objective lens MPLAPON 50: 50XLEXT (multiplying power: 50 times, numerical aperture: 0.95, liquid immersion type: air, mechanical lens barrel length: infinity, cover glass thickness: 0, number of fields of view: FN 18)
Optical zoom magnification 1 time
Scanning mode XYZ high precision (high resolution: 60nm, number of pixels of input data: 1024X 1024)
Input image size [ number of pixels ]: transverse 257 μm×longitudinal 258 μm [1024×1024]
(Since it is measured in the transverse direction, the evaluation length is 257. Mu.m)
DIC closing
Multiple layers of closing
Laser intensity of 100
Offset 0
Confocal level 0
Beam diameter diaphragm is closed
Image averaging 1 time
Noise reduction, on
Brightness non-uniformity correction, on
Optical noise filter on
Cut-off λc=200 μm, no λs and no λf
Filter-Gaussian filter
Noise removal, pretreatment for measurement
Surface (tilt) correction by implementing
Brightness is regulated to be in the range of 30-50
The brightness is a value to be appropriately set according to the hue of the measurement object. The above setting is a proper value when the surface of the surface-treated copper foil having L of-69 to-10, a of 2 to 32, and b of 2 to 21 is measured.
< Measurement of color tone of measurement object >
Measurement of L, a, and b of the CIE L x a x b x color system was performed according to JIS Z8730:2009 using MiniScan (registered trademark) EZ Model 4000L manufactured by HunterLab corporation as a measurement instrument. Specifically, the surface to be measured of the surface-treated copper foil or the copper foil obtained in the examples and comparative examples was pressed against the photosensitive part of the measuring instrument, and the measurement was performed without light entering from the outside. The measurements of L, a, and b were performed based on the geometric condition C of JIS Z8722:2009. The main conditions of the measuring instrument are as follows.
Optical system D/8 degree, integrating sphere size 63.5mm, observation light source D65
Measurement mode reflection
Illumination diameter 25.4mm
Diameter measurement of 20.0mm
Measuring wavelength, interval 400-700 nm and 10nm
Light source, pulse xenon lamp, 1 luminescence/measurement
Traceability standards CIE 44 and ASTM E259 based correction according to the American National Institute of Standards and Technology (NIST)
Standard observer 10 °
The following object colors were used for the white tiles to be the measurement standards.
In the case of measurement at D65/10, the values in the CIE XYZ color system are X:81.90, Y:87.02, Z:93.76
< Peel Strength >
After the surface-treated copper foil was bonded to a resin base material made of a low dielectric material, a circuit having a width of 3mm was formed in the MD direction (the longitudinal direction of the rolled copper foil). The formation of the circuit is carried out according to a usual method. Then, the strength (MD 90 peel strength) at a speed of 50 mm/min in the 90 DEG direction with respect to the surface of the resin substrate, that is, in the vertical upper direction with respect to the surface of the LCP substrate was measured in accordance with JIS C6471:1995. The measurement was performed 3 times, and the average value was used as a result of peel strength. When the peel strength is 0.50kgf/cm or more, the adhesion between the circuit (surface-treated copper foil) and the LCP substrate is satisfactory.
The results of the above-described characteristic evaluation are shown in table 1.
TABLE 1
As shown in table 1, the surface treated copper foil of examples 1 to 8, in which the heteroaromatic compound layer was formed and the Ssk was in the range of-2.00 to-0.10, had the same degree of peel strength as the surface treated copper foil of comparative example 2, in which the surface treated layer such as the roughened layer was formed, and the adhesion between the LCP base material and the surface treated copper foil was good.
In contrast, the copper foil of comparative example 1, in which the heteroaromatic compound layer was not formed, had low peel strength. Further, it is considered that the peel strength was low because the roughening in comparative example 3 was smaller than that in comparative example 2.
The above results are surprising. As described above, the adhesion between the copper foil and the resin substrate such as the LCP substrate is generally improved by forming a surface-treated layer containing roughened particles. In the embodiment of the present invention, the presence of the heteroaromatic compound layer having a smooth surface sufficiently ensures adhesion to a resin substrate such as an LCP substrate.
From the above results, it is apparent that according to the embodiments of the present invention, it is possible to provide a surface-treated copper foil capable of suppressing the time and cost required for production and improving adhesion to a resin base material, particularly a resin base material suitable for high-frequency applications. Further, according to the embodiment of the present invention, a copper-clad laminate which is excellent in adhesion between a resin base material, particularly a resin base material suitable for high-frequency applications, and a surface-treated copper foil, while suppressing the time and cost required for production, can be provided. Further, according to the embodiment of the present invention, a printed wiring board can be provided which is excellent in adhesion between a resin base material, particularly a resin base material suitable for high-frequency applications, and a circuit pattern while suppressing the time and cost required for manufacturing.
Embodiments of the present invention may also employ the following aspects.
<1>
A surface-treated copper foil comprising a copper foil and a heteroaromatic compound layer formed on at least one surface of the copper foil,
The heteroaromatic compound layer contains a heteroaromatic compound and Ssk is-2.00 to-0.10, and the heteroaromatic compound has a heterocycle containing a nitrogen atom as a heteroatom.
<2>
The surface-treated copper foil according to <1>, wherein the heterocyclic ring is a 5-membered ring containing 1 to 3 nitrogen atoms.
<3>
The surface-treated copper foil according to the above <1> or <2>, wherein the heteroaromatic compound is a condensed cyclic compound of a benzene ring and the heterocyclic ring, a condensed cyclic compound of 2 or more of the heterocyclic rings, or a monocyclic compound of the heterocyclic ring.
<4>
The surface-treated copper foil according to any one of <1> to <3>, wherein the heteroaromatic compound is 1 or more selected from the group consisting of benzotriazole, indazole, benzimidazole, indole, triazolopyridine, 1-methylbenzotriazole, 5-methylbenzotriazole and 1,2, 3-triazole.
<5>
The surface treated copper foil according to any one of <1> to <4>, wherein Ssk is-2.00 to-0.50.
<6>
The surface-treated copper foil according to the above <5>, wherein Ssk is-2.00 to-0.80.
<7>
The surface-treated copper foil according to the above <5>, wherein Ssk is-1.50 to-0.80.
<8>
The surface-treated copper foil according to any one of <1> to <7>, wherein the heteroaromatic compound layer has a Vmp of 0.001 to 0.010 μm 3/μm2.
<9>
The surface-treated copper foil according to <8>, wherein the Vmp is 0.001 to 0.006 μm 3/μm2.
<10>
A copper-clad laminate comprising the surface-treated copper foil according to any one of the above items <1> to <9>, and a resin substrate for the heteroaromatic compound layer attached to the surface-treated copper foil.
<11>
A printed wiring board comprising a circuit pattern formed by etching the surface-treated copper foil of the copper-clad laminate described in <10 >.
Claims (11)
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2022-190461 | 2022-11-29 | ||
| JP2022190461 | 2022-11-29 | ||
| PCT/JP2023/035031 WO2024116581A1 (en) | 2022-11-29 | 2023-09-26 | Surface-treated copper foil, copper-cladded laminate plate, and printed wiring board |
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| Publication Number | Publication Date |
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| CN119546801A true CN119546801A (en) | 2025-02-28 |
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| CN202380053761.0A Pending CN119546801A (en) | 2022-11-29 | 2023-09-26 | Surface treatment of copper foil, copper clad laminates and printed circuit boards |
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| Country | Link |
|---|---|
| JP (1) | JPWO2024116581A1 (en) |
| KR (1) | KR20250023530A (en) |
| CN (1) | CN119546801A (en) |
| TW (1) | TWI867785B (en) |
| WO (1) | WO2024116581A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61266241A (en) * | 1985-05-21 | 1986-11-25 | 株式会社日立製作所 | Surface treating method of copper |
| JP2512762B2 (en) * | 1987-08-25 | 1996-07-03 | 東芝ケミカル株式会社 | Multilayer printed wiring board |
| JPH08311658A (en) * | 1995-05-17 | 1996-11-26 | Nippon Parkerizing Co Ltd | Composition for surface treatment of copper-based metal material |
| JP2006253424A (en) * | 2005-03-10 | 2006-09-21 | Nikko Kinzoku Kk | Method of manufacturing printed wiring board |
| JP2011108848A (en) * | 2009-11-17 | 2011-06-02 | Ube Nitto Kasei Co Ltd | Metal foil with insulation function membrane, flexible metal cladded laminated plate, electronic component mounting module, and manufacturing method thereof |
| JP2012112009A (en) | 2010-11-26 | 2012-06-14 | Hitachi Cable Ltd | Copper foil, and method for producing copper foil |
| JP5656081B2 (en) * | 2011-04-18 | 2015-01-21 | メック株式会社 | Film forming liquid and film forming method using the same |
| US9508951B2 (en) * | 2012-07-24 | 2016-11-29 | Mitsui Mining & Smelting Co., Ltd. | Electrode foil and organic light-emitting device |
| JP2016151046A (en) * | 2015-02-17 | 2016-08-22 | 四国化成工業株式会社 | Surface treatment agent, resin composition, and use of the same |
| CN108431298B (en) * | 2016-01-27 | 2019-06-21 | 株式会社新技术研究所 | Copper or copper alloy article containing surface-modified polyester-based resin, and production method |
| JP7356209B2 (en) * | 2017-03-31 | 2023-10-04 | Ｊｘ金属株式会社 | Surface-treated copper foil, surface-treated copper foil with resin layer, copper foil with carrier, laminate, method for manufacturing printed wiring boards, and method for manufacturing electronic devices |
| JP6779557B1 (en) * | 2020-07-20 | 2020-11-04 | メック株式会社 | A composition for forming a film, a method for producing a surface-treated metal member, and a method for producing a metal-resin composite. |
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2023
- 2023-09-26 JP JP2024561207A patent/JPWO2024116581A1/ja active Pending
- 2023-09-26 CN CN202380053761.0A patent/CN119546801A/en active Pending
- 2023-09-26 WO PCT/JP2023/035031 patent/WO2024116581A1/en not_active Ceased
- 2023-09-26 KR KR1020257001200A patent/KR20250023530A/en active Pending
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| KR20250023530A (en) | 2025-02-18 |
| TWI867785B (en) | 2024-12-21 |
| WO2024116581A1 (en) | 2024-06-06 |
| JPWO2024116581A1 (en) | 2024-06-06 |
| TW202421846A (en) | 2024-06-01 |
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