TW201542351A - Roughened copper foil, copper-clad laminate, and printed wiring board - Google Patents

Abstract

This roughened copper foil is provided with a roughened surface having a fine uneven surface structure formed on both surfaces of a copper foil by needle-like or plate-like protrusions having a maximum length of 500 nm, and comprises a copper composite compound containing copper oxide. One surface of the copper foil is a laser-irradiated surface that has been irradiated by laser light during laser processing, while the other surface is an adhesion surface that adheres with an insulation layer construction material. The roughened copper foil for laser drilling is suitable for the formation of a buildup layer of a printed wiring board, and forms a high quality multilayer printed wiring board.

Description

Roughening copper foil, copper clad laminate and printed circuit board

The present application relates to a roughened copper foil, a copper clad laminate, and a printed circuit board, and more particularly to a roughened copper foil, a copper clad laminate, and a printed circuit board having a roughened surface which is a laser light absorbing surface. .

In recent years, when a copper-clad laminate is formed into a small-diameter via hole having a diameter of 100 μm or less, laser hole drilling is mainly performed. When laser drilling is performed, a copper foil subjected to "blackening treatment" or a copper-clad laminate which has been subjected to blackening treatment is used.

For example, in Patent Document 1, as a printed circuit board having a high conductivity of a via hole and a method of manufacturing the same, a project of forming a blackened film by blackening a metal foil is disclosed; The bottom of the via hole forming portion of the substrate is formed so that the blackened film is in the opposite state to cover the metal foil; the insulating substrate is irradiated with the laser to form a conductive hole with the metal foil as the bottom; for the exposed bottom of the via hole The metal foil is subjected to a desmear process; the metal foil exposed at the bottom of the via hole is soft-etched; the surface of the metal foil at the bottom of the via hole is confirmed by soft etching to have no blackened film; the metal is formed inside the via hole A method of electroplating a film; a method of forming a conductor pattern by etching a metal foil.

Also, in Patent Document 2, it is suitable to provide a laser-based method. For the purpose of forming a through-hole, a via hole for a via hole or a copper-clad laminate for a recess in the copper foil circuit layer of the outer copper foil, it is shown that "the copper layer is laminated on the copper-clad laminate. A fine copper oxide or fine copper particles are formed on the surface of the foil, and a copper clad laminate having a reflectance of laser light of 86% or less and a luminance (L value) of 22 or less is used. Then, in order to obtain a copper-clad laminate which satisfies the condition that the reflectance of the laser light is 86% or less and the luminance (L value) is 22 or less, it is described that the surface of the copper foil which forms the outer layer of the copper-clad laminate is applied. Blackening treatment.

[Previous Technical Literature]

[Patent Literature]

Patent Document 1: Japanese Patent Laid-Open No. Hei 11-261216

Patent Document 2: Japanese Patent Laid-Open Publication No. 2001-68816

However, when the metal foil disclosed in Patent Document 1 is used, since the blackening treatment is performed on the surface of the insulating substrate, a conductor pattern having good adhesion to the insulating resin substrate can be obtained. However, Patent Document 1 discloses a metal foil used for forming a via hole by a so-called common mask method. In other words, in the case of using the metal foil described in Patent Document 1, it is necessary to form an opening in the via hole forming portion of the metal foil by etching, and it is not possible to form the via hole by a so-called direct laser method.

On the other hand, when the copper clad laminate shown in Patent Document 2 is used, it is not necessary to perform etching of the via hole forming portion, and the copper foil and the insulating layer can be laser-processed at the same time, but the laser opening processing property is The situation that produces a difference. If at When the surface of the copper foil is blackened, needle-like crystals are formed on the surface of the copper foil, and the surface becomes a black rough surface and the absorbance of the laser light is increased. This needle crystal is elongated from the surface of the copper foil, so it is very fragile. Therefore, in the operation of the copper clad laminate, if a slight frictional force is applied to the blackened surface in contact with other objects, the needle crystals at this point are broken, and the place becomes locally lustrous. This result produces an in-plane variation in the absorbance of the laser light. Further, if the surface shape of the blackened surface changes, and the entire surface becomes a shiny surface, the laser drilling process may not be performed at all. Therefore, in order to process the via hole well and to suppress the low yield of the product, it is necessary to pay great attention to the damage of the blackened surface when operating the copper clad laminate having the blackened layer.

Therefore, in the market, it has a roughened surface which is suitable for laser drilling and has a high abrasion resistance, is easy to handle, and has a high laser absorbance, and is excellent in adhesion to the insulating layer. A copper foil for laser drilling, a copper clad laminate using the roughened copper foil, and a printed circuit board have been expected.

Therefore, as a result of intensive studies by the inventors of the present invention, it has been found that by using the roughened copper foil for laser hole drilling described below, the copper clad laminate using the roughened copper foil, and the printed circuit board, Solve the above problems. The outline of the invention related to the present application will be described below.

(roughening copper foil for laser drilling)

The roughened copper foil for laser drilling according to the present application is characterized in that it has a needle shape formed by a copper composite compound containing copper oxide and having a maximum length of 500 nm or less on both surfaces of the copper foil. Or a plate-like convex shape In the roughened surface of the fine concavo-convex structure, one surface of the copper foil is a laser irradiation surface that is irradiated with laser light during laser processing, and the other surface is a surface of the insulating layer.

(Copper laminate)

A copper clad laminate according to the present application is characterized in that the roughened copper foil for laser drilling according to the present application is laminated on at least one side of the insulating constituent.

(A printed circuit board)

A printed circuit board according to the present application is characterized in that it has a copper layer formed by using a roughened copper foil for laser opening processing according to the present application.

The roughened copper foil for laser hole drilling processing according to the present application includes a laser irradiation surface irradiated with laser light during laser processing, and a bonding surface with the insulating material, respectively, including scratch resistance A roughened surface of a fine concavo-convex structure formed of a needle-like or plate-like convex portion formed of a copper composite compound containing copper oxide and having a maximum of 500 nm or less. As long as the copper-clad laminate using the roughened copper foil for laser drilling is used, it is excellent not only in adhesion to the insulating member, but also has high laser absorbance and excellent scratch resistance. The roughened surface of the fine concavo-convex structure formed by the copper-copper composite compound is present on the outer surface, and exhibits excellent laser drilling performance, and the operator does not need to special when operating the copper-clad laminate. Note that it can improve work efficiency. As a result, the difference in the processing performance of the laser opening of the copper clad laminate is reduced, and the opening of the stability becomes possible. In particular, this laser opening plus The roughening copper foil is suitable for the formation of a build-up layer of a printed circuit board, and can provide a good quality multilayer printed circuit board.

1‧‧‧Copper laminate

2‧‧‧ copper foil

3‧‧‧The roughening surface of the electrode side

4‧‧‧The roughening surface of the surface

5‧‧‧Insulation

6‧‧‧ Copper foil on the opposite side of the laser irradiation surface

7‧‧‧Insulation layer

8‧‧‧ Inner layer circuit

9‧‧‧ Inner substrate

10‧‧‧ Guide hole

23‧‧‧1st build-up wiring circuit

24‧‧‧Electroplating

31‧‧‧1st build-up circuit layer

32‧‧‧2nd layer

40‧‧‧Layer with the first build-up layer

41‧‧‧Layer with the first build-up circuit layer

42‧‧‧Layer with second build-up

FIG. 1 is a scanning electron microscope observation photograph of the roughened surface of the electrode surface side and the deposition surface side of the roughened copper foil (electrolytic copper foil) for laser drilling processing according to the present application (oxidation) The immersion time of the treatment was 2 minutes).

Fig. 2 is a scanning electron microscope observation photograph of a fine concavo-convex structure provided on a roughened surface of a roughened copper foil for laser opening processing according to the present application.

Fig. 3 is a schematic cross-sectional view showing the basic layer configuration of a copper clad laminate used in the laser drilling method relating to the present application.

Fig. 4 is a schematic cross-sectional view showing the basic layer configuration of a copper clad laminate used in the laser drilling method of the present application.

Fig. 5 is a schematic cross-sectional view showing the concept of laser drilling processing when a blind via hole is formed using laser light.

Fig. 6 is a schematic cross-sectional view showing the manufacturing process of the process for producing a multilayer printed circuit board by the build-up method.

Fig. 7 is a schematic cross-sectional view showing the manufacturing process of the process for producing a multilayer printed circuit board by the build-up method.

Hereinafter, the "form of a copper clad laminate" and "a form of a printed circuit board" relating to the present application will be described. Also, in the "form of copper clad laminates" In the following, the "formation of the roughened copper foil for laser drilling" related to this application will be described.

<Form of copper clad laminate>

Copper clad laminate

The copper-clad laminate according to the present invention is characterized in that the roughened copper foil for laser opening processing according to the present application is characterized in that at least one layer of the constituent material of the insulating layer is laminated, mainly as It is used as a manufacturing material for printed circuit boards manufactured by laser drilling processing. Further, the copper-clad laminate according to the present application may be a material for roughening the copper foil for laser drilling according to the present application, at least on one side of the insulating member. It is possible to laminate a copper-clad laminate on both sides of the roughened copper foil for laser boring processing in accordance with the present application on both sides of the insulating structural member. Hereinafter, first, the roughened copper foil for laser drilling processing according to the present application will be described.

1-1. Roughening copper foil for laser drilling

The roughened copper foil for laser hole drilling according to the present application has a maximum length of 500 nm or less formed on both sides of the copper foil by a copper composite compound containing copper oxide (and, if necessary, cuprous oxide). The roughened surface of the fine concavo-convex structure formed by the needle-like or plate-like convex portion. In the following, the roughened surface of the fine concavo-convex structure formed by the convex portion having a needle shape or a plate shape having a maximum length of 500 nm or less formed by a copper composite compound containing copper oxide is referred to as a roughened surface. . In the following, the roughened copper foil for laser drilling according to the present application having such a roughened surface on both sides is referred to as "two-side roughening copper foil". When the copper-clad laminate is produced by using the two-side roughened copper foil, the roughened surface on one side is used as a copper clad laminate. The laser-illuminated surface of the plate has the roughened surface on the other side as the back surface of the insulating layer, and the laser drilling performance is good, and the adhesion between the copper layer and the insulating layer is good. Copper clad laminate. Further, in the copper clad laminate obtained by laminating the insulating layer constituent material and the above-described two-side roughening treatment of the copper foil, the copper foil layer formed by the two-side roughening treatment of the copper foil or the like is referred to as a copper layer.

Next, a description will be given of a copper foil which can be suitably used in the production of a roughened copper foil for laser drilling in accordance with the present application. The copper foil may be either a rolled copper foil or an electrolytic copper foil, and the type of the copper foil is not particularly limited. Further, although the thickness of the copper foil is not particularly limited, the thickness of the copper foil is determined by considering the laser drilling performance when the via hole is formed by laser drilling for the copper clad laminate. 12 μm or less is preferred. When considering the ease of operation, it is preferably 7 μm to 12 μm. However, the term "copper foil" as used herein refers to a copper foil before the formation of the fine concavo-convex structure.

This copper foil, on the side of the laser light irradiation side, "measures the surface area (three-dimensional area: Aμm ² ) in the field of the secondary region of 57570 μm ² by the laser method, and the ratio of the area of the secondary element field [(A)/( 57570)] The calculated surface area ratio (B)" is preferably 1.1 or more, and more preferably 1.5 or more. When the surface area ratio (B) is 1.1 or more, the laser drilling performance is good, and it is more preferably 1.5 or more. On the other hand, if the value of the specific surface area ratio (B) exceeds 3, the thickness of the copper foil itself may vary, and as a result, the aperture diameter may be easily different. Further, if the difference in thickness of the copper foil itself is too large, the roundness of the via hole formed by the laser opening process is also lowered. Therefore, the surface area ratio (B) of the surface on the laser light irradiation side of the copper foil is preferably 3 or less.

Moreover, the surface roughness (Rzjis) of the surface of the copper foil on the side irradiated with the laser light It is preferably 2.0 μm or more. In the copper foil having a surface having a surface roughness (Rzjis) of 2.0 μm or more, by forming the fine concavo-convex structure, the laser drilling performance is further improved, and when the surface roughness (Rzjis) is 3.0 μm or more, good. The thicker the surface roughness, the lower the reflectance of the laser light in the copper layer, and the better the laser hole drilling performance. On the other hand, if the surface roughness (Rzjis) is 6.0 μm or more, in this case, the thickness of the copper foil itself may vary. As described above, the laser aperture is likely to be different, and the difference in the thickness of the copper foil itself is too large. Then the roundness of the guide hole will also be low. Therefore, the surface roughness (Rzjis) of the surface on the side of the laser light irradiation surface of the copper foil is preferably 6.0 μm or less.

On the other hand, the surface characteristics of the contact surface of the insulating resin substrate of the copper foil are not particularly limited, but the circuit formation is performed using the copper clad laminate, and the viewpoint of forming a fine pitch circuit having a good etching factor is employed. The surface roughness (Rzjis) is preferably 2.0 μm or less, more preferably 1.5 μm or less, and still more preferably 1.0 μm or less. Further, the glossiness of the surface (Gs 60°) is preferably 100 or more, and more preferably 300 or more.

When the fine concavo-convex structure is formed on the surface of the insulating layer constituent material of the copper foil having the above surface characteristics, not only good adhesion to the insulating layer constituent material but also a circuit having high frequency characteristics can be obtained. That is, in order to suppress transmission loss due to the skin effect in the high frequency circuit, it is required to form a circuit by a smooth conductor on the surface. Here, in the case where the fine concavo-convex structure is provided on the succeeding surface, it is considered that there is a transmission loss of a high-frequency signal due to the fine concavo-convex structure provided on the surface of the adjoining surface. However, as described above, the fine concavo-convex structure is formed by a convex portion formed of a copper composite compound containing copper oxide (and, if necessary, cuprous oxide), and thus the fine The embossed structure layer does not flow through the high frequency signal. Therefore, the roughened copper foil exhibits high frequency characteristics equivalent to those in the case of a copper layer formed without a roughened copper foil having a roughened surface. Further, the roughened surface has good adhesion to the insulating layer constituent material having a low dielectric constant for use in a high-frequency substrate. Therefore, the double-faced roughened copper foil having the fine uneven structure on both sides of the copper foil is also suitable as a circuit forming material for a high-frequency circuit forming material and a multilayer printed wiring board.

1-2. Fine uneven structure

The fine concavo-convex structure referred to in the present application is formed by "a needle-like or plate-like convex portion having a maximum length of 500 nm or less formed of a copper composite compound containing copper oxide". The fine concavo-convex structure is, for example, oxidized by a method described later on the surface of the copper foil, and then, if necessary, subjected to a reduction treatment. By using the two-side roughening treatment of the copper foil, a copper clad laminate is produced by laminating the insulating layer constituent material, and the fine concavo-convex structure can be provided not only on the surface but also the insulating layer constituent material and copper can be easily obtained. A copper clad laminate with good adhesion to the layer. Hereinafter, the case where the electrolytic copper foil is used will be described as an example with reference to the drawings, and the fine concavo-convex structure referred to in the present application will be described in detail.

In the first embodiment, the roughened surface (the roughened surface 3 on the electrode surface side and the roughened surface 4 on the deposition surface side) are shown in the case of using a general-purpose electrolytic copper foil. 3 to 6) The observation photograph of the scanning electron microscope. As shown in Fig. 1, it was observed that each of the roughened surfaces of the electrolytic copper foil was protruded into a needle-like or plate-like fine convex shape. The portions are densely concentrated adjacent to each other, and an extremely fine concavo-convex structure is formed on the surface of the electrolytic copper foil. These convex portions are provided along the surface shape of the electrolytic copper foil, for example, on the surface of the electrolytic copper foil.

As shown in Fig. 1, when the roughened surface on the surface side of the electrode and the roughened surface on the side of the deposited surface are used, the surface shape of each surface is different. The difference in the surface shape of this giant is considered to be due to the difference in the surface shape of the electrode surface of the electrodeposited copper foil itself before the formation of the fine uneven structure and the giant surface of the deposition surface. From the viewpoint of the fact that the fine concavo-convex structure referred to in the present application is provided on the surface of the copper foil, it is considered that the superficial surface shape of the copper foil before the formation of the fine concavo-convex structure can be maintained.

The electrolytic copper foil is obtained by electrolyzing copper on the surface of a rotary type electrolytic drum, and is obtained by winding this. Therefore, the surface of the electrodeposited copper foil on the side in contact with the surface of the electrolytic drum (hereinafter referred to as "electrode surface") is generally smooth and shiny due to the surface shape of the electrodeposited copper foil. On the other hand, the other surface (hereinafter referred to as "precipitation surface") has a concavo-convex shape formed by analysis of copper. Referring to Fig. 1, it is understood that the roughened surface maintains the surface shape of the macroscopic surface before the roughening treatment of each surface of the electrolytic copper foil, and the electrode surface has a relatively smooth giant surface shape, and the precipitated surface has irregularities. The superficial surface shape. This is considered to be the same as the superficial surface shape of the electrolytic copper foil before the roughening treatment. The fine concavo-convex structure referred to in the present application is formed in a needle-like or plate-like convex portion having a maximum length of 500 nm or less along the surface shape, such as a surface of a copper foil, and is densely disposed on the surface of the copper foil. After the fine concavo-convex structure, the superficial surface shape of each surface of the electrolytic copper foil is also considered to be maintained.

Further, the fine concavo-convex structure is formed by a convex portion having a maximum length of 500 nm or less. Referring to Fig. 1, the arrangement pitch of the convex portions arranged on the surface of the electrodeposited copper foil is shorter than the length of each convex portion. Here, in the laser drilling process, a carbon dioxide gas laser having a dominant wavelength of 9.4 μm and 10.6 μm is used. The arrangement pitch of each convex portion is shorter than the emission wavelength of the carbon dioxide gas laser, and the roughening treatment surface will The reflection of the laser light caused by the carbon dioxide gas laser is suppressed, and the laser light is absorbed at a high light absorption rate. Further, the maximum length of the convex portion forming the fine concavo-convex structure provided on the roughened surface is as short as 500 nm or less, unlike the conventional blackening treatment, there is no convex portion which is elongated and elongated from the surface of the copper foil. Even if another object comes into contact with the surface of the roughened surface, damage such as breakage of the convex portion can be suppressed. Therefore, in the case where the copper foil is roughened on both sides, even if the operator's finger or the like comes into contact with the roughened surface during the operation, the convex portion forming the fine uneven structure is not broken and the treated surface is roughened. The surface shape is locally changed, or the fine powder of copper oxide is scattered to the so-called dust falling around, and can be easily handled. As a result, it is possible to prevent the difference in the processing performance of the laser opening, or the in-plane difference in the adhesion between the two-sided roughened copper foil and the insulating layer constituent material.

Next, the "maximum length" of the convex portion will be described with reference to Fig. 2 . Fig. 2 is a scanning electron microscope observation photograph showing a cross section of a roughened copper foil for laser drilling processing according to the present application. As shown in Fig. 2, in the cross section of the roughened copper foil, a portion having a thin line shape was observed as a convex portion. In Fig. 2, it was confirmed that the surface of the copper foil was covered by the infinite number of convex portions which were dense with each other, and each of the convex portions was provided to protrude from the surface of the copper foil along the surface shape of the copper foil. In the present application, the "maximum length of the convex portion" means the length of the convex portion of the roughened copper foil, and the length from the bottom end to the tip end of each of the convex portions observed in the line (line division) is measured. The maximum value of the time. If only the processing performance of the laser opening on the laser irradiation surface is considered, the longer the maximum length of the convex portion, the higher the light absorption rate of the laser light, and the processing performance of the laser opening is improved. However, since the maximum length of the convex portion is shorter, the other object is less likely to be damaged when it comes into contact with the roughened surface, so that the operation becomes easy. Again, the most convex When the large length is short, the surface shape of the copper foil before the roughening treatment can be maintained, and the change in the surface roughness before and after the roughening treatment can be suppressed. Therefore, the shortest length of the convex portion can obtain good adhesion to the insulating layer constituent material by the fine nano anchoring effect, and is equivalent to the case where the so-called roughened copper foil is used. The formation of fine pitch circuits with good etch factors becomes possible. Therefore, from the viewpoint of maintaining good laser drilling performance and making the operation easier, and obtaining good adhesion to the insulating layer constituent material and obtaining a good etching factor, The maximum length of the convex portion is preferably 400 nm or less, more preferably 300 nm or less. On the other hand, if the maximum length of the convex portion is less than 100 nm, the laser hole drilling performance is low. Further, if the maximum length of the convex portion is too short, a sufficient nano anchoring effect may not be obtained. Therefore, the maximum length of the convex portion is preferably 100 nm or more.

Further, as shown in Fig. 2, the fine concavo-convex structure was visually confirmed to be a layered portion in the surface layer portion of the copper foil. Hereinafter, a field in which the fine concavo-convex structure is occupied as a layer in the surface layer portion of the copper foil is referred to as a fine concavo-convex structure layer. The fine concavo-convex structure layer corresponds to a length (height) in the thickness direction in which the convex portion protrudes from the surface of the copper foil. However, the length or the protruding direction of each convex portion forming the fine concavo-convex structure is not constant, and the protruding direction of each convex portion is not parallel to the thickness direction of the copper foil. Moreover, the height of each convex portion is different. Therefore, the thickness of the fine concavo-convex structure layer is different. However, there is a certain correlation between the maximum length of the convex portion and the fine concavo-convex structure layer. As a result of the repeated test, when the average thickness of the fine concavo-convex structure layer is 400 nm or less, the maximum length of the convex portion is 500 nm or less. In this case, as described above, since there is no convex portion that protrudes long from the surface of the copper layer, not only the difference can be made. Good laser hole drilling and easy handling. At the same time, good adhesion to the insulating layer constituent material can be obtained, and the difference in adhesion between the two surfaces can be prevented. Moreover, a good etching factor can be obtained.

When the roughened surface is planarly observed at a magnification of 45° or more at a tilt angle of 45° or more using a scanning electron microscope, the length of the tip end portion which can be separated from the other convex portions can be observed in the convex portion adjacent to each other. Below 250 nm is preferred. Here, the length of the tip end portion which can be observed separately from the other convex portions (hereinafter, the case where only the length of the tip end portion is slightly) is the length shown below. For example, when the surface of the roughened surface is observed by a scanning electron microscope, the first figure is referred to. As described above, the convex portion is densely formed in a needle shape or a plate shape on the roughened surface. Since it is provided on the surface of the copper foil, the bottom end portion of the convex portion, that is, the interface between the convex portion formed by the copper composite compound and the copper foil cannot be observed from the surface of the copper foil. Therefore, as described above, when the roughened surface of the copper foil is observed in a planar manner, the convex portions that are densely adjacent to each other are separated from the other convex portions and can be independently observed as a convex portion. It is referred to as "the length of the tip end portion which can be observed separately from other convex portions", and the length of the tip end portion refers to the tip end of the convex portion (that is, the tip end of the tip end portion) to other convex shapes. The length of the portion at which the bottom end portion of the observation portion can be separated can be separated.

When the length of the tip end portion of the convex portion is 250 nm or less, the maximum length of the convex portion is approximately 500 nm or less. As described above, in consideration of the laser hole drilling performance, the maximum length of the convex portion is preferably long, and the length of the tip end portion of the convex portion is also preferably the length. However, if the length of the tip end portion of the convex portion is longer, it is easily damaged when other objects are in contact. Convex When the maximum length of the portion is shorter, the surface shape of the copper foil before the roughening treatment can be maintained, and the change in the surface roughness before and after the roughening treatment can be suppressed. Therefore, the shortest length of the convex portion can obtain good adhesion to the insulating layer constituent material by the fine nano anchoring effect, and is equivalent to the case where the so-called roughened copper foil is used. The formation of fine pitch circuits with good etch factors becomes possible. Therefore, from the viewpoint of maintaining excellent laser drilling performance when the roughened surface is used as a laser irradiation surface, and making the operation easier, and obtaining a material which is excellent in composition with the insulating layer, The length of the tip end portion of the convex portion is preferably 200 nm or less and more preferably 100 nm or less from the viewpoint of adhesion and a good etching factor. On the other hand, if the length of the tip end portion of the convex portion is less than 30 nm, the laser hole drilling performance is lowered. Therefore, the length of the tip end portion of the convex portion is preferably 50 nm or more.

Further, for the maximum length of the convex portion, the length of the tip end portion of the convex portion is preferably 1/2 or less. When the ratio is 1/2 or less, the tip end portion of the convex portion protrudes from the surface of the copper foil by being separated from the other convex portions, and the surface of the copper foil can be more densely covered by the fine uneven structure.

The surface area (hereinafter, simply referred to as "Kr adsorption specific surface area") when the ruthenium is adsorbed and measured on the surface of the fine uneven structure of the roughened surface is preferably 0.035 m ² /g or more. This is because the Kr adsorption specific surface area is 0.035 m ² /g or more, and the average height of the convex portion on the roughened surface is 200 nm, which ensures stable laser drilling performance and resistance. The scratch performance and the good adhesion to the insulating layer constituent material. Here, the upper limit of the Kr adsorption specific surface area is not limited, and the upper limit is about 0.3 m ² /g, and more preferably 0.2 m ² /g. Moreover, the specific surface area of Kr adsorption at this time is the specific surface area of McMurstock. The pore distribution measuring device 3Flex measures the sample at 300 ° C for 2 hours as a pretreatment, uses the liquid nitrogen temperature as the adsorption temperature, and uses krypton (Kr) as the adsorption gas.

Next, the components constituting the fine concavo-convex structure will be described. As described above, the convex portion is formed of a copper composite compound containing copper oxide. In this application. From the viewpoint of good laser drilling performance, the copper composite compound constituting the fine uneven structure on the side of the laser irradiation surface is preferably formed of copper oxide, and is mainly composed of copper oxide. It may contain cuprous oxide. Also, in any case, a small amount of metallic copper may be contained.

In other words, the peak area of Cu(I) obtained by analyzing the constituent elements of the fine concavo-convex structure by X-ray photoelectron spectroscopy (hereinafter referred to as "XPS"), and Cu (II) The total area of the peak areas, the ratio of the area of the wave front of Cu(I) (hereinafter referred to as the occupied area ratio), and the case where the roughened surface is used as the laser irradiation surface is less than 50%. good.

Here, a method of analyzing the constituent elements of the fine concavo-convex structure layer by XPS will be described. When the constituent elements of the fine concavo-convex structure layer are analyzed by XPS, the peaks of Cu(I) and Cu(II) can be separated and detected. However, when the peaks of Cu(I) and Cu(II) are separated and detected, most of the Cu(I) peaks may be repeatedly observed with the Cu(0) peak. When the peak of Cu(0) is repeatedly observed, the shoulder is included and is regarded as a Cu(I) peak. That is, in the invention of the present application, the constituent elements of the copper composite compound which forms the fine concavo-convex structure by XPS analysis will appear in Cu(I) corresponding to the binding energy of Cu 2p 3/2 of 932.4 eV, and appear at 934.3 eV. Cu (II) photoelectron detection can be obtained from each wave Shape separation, the area ratio of Cu(I) peaks is specified from the wave front area of each component. However, Quantum 2000 (beam condition: 40 W, 200 μm diameter) manufactured by ULVAC PHI Co., Ltd. was used as the XPS analyzer, and "MultiPack ver.6.1A" was used as the analysis software to perform the state. Semi-quantitative determination by narrow scan.

The Cu(I) peak obtained as described above is considered to be derived from monovalent copper constituting cuprous oxide (oxidized first copper: Cu ₂ O). Then, the Cu(II) peak is considered to be derived from bivalent copper constituting copper oxide (oxidized second copper: CuO). Further, the Cu(0) peak is considered to be derived from the zero-valent copper constituting the metallic copper. Therefore, if the occupation ratio of the wave front area of Cu(I) is less than 50%, the ratio of cuprous oxide in the copper composite compound constituting the roughened layer is smaller than the ratio of copper oxide. Considering the processing performance of the laser opening, the smaller the occupancy of the Cu(I) peak is, the better. That is to say, if the occupancy rate is less than 40%, less than 30%, less than 20%, etc., the smaller the value, the higher the processing performance of the laser opening, and if the occupation rate is 0%, it constitutes a fine The convex portion of the uneven structure is preferably formed only of copper oxide.

On the other hand, the copper composite compound preferably contains copper oxide and cuprous oxide on the surface of the insulating layer constituent material, and cuprous oxide is preferred as the main component. Specifically, the Cu(I) peak occupancy ratio is preferably 50% or more and more preferably 70% or more, and more preferably 80% or more, on the surface of the insulating layer constituent material. Copper oxide has a high solubility in an acid such as an etching solution compared to cuprous oxide. Therefore, when the area ratio of the Cu(I) peak is less than 50%, the laser layer is subjected to laser drilling, and then the circuit is formed by an etching method, and the constituent components of the fine uneven structure are changed. In the case where it is easy to dissolve in the etching liquid, there is a case where the adhesion between the copper circuit and the insulating layer constituent material is lowered, which is not preferable. The upper limit of the area occupied by the peak of Cu(I) is not particularly limited, but is 99% or less. The lower the occupied area ratio of the Cu(I) peak, the more the adhesion of the insulating layer constituent material to the bonding surface tends to be improved. Therefore, in order to obtain good adhesion between the two, the exclusive area ratio of the Cu(I) peak is preferably 98% or less, and more preferably 95% or less. Further, the area ratio of the Cu(I) peak can be calculated by a calculation formula of Cu(I) / {Cu(I) + Cu(II)} × 100 (%).

The fine concavo-convex structure described above can be formed, for example, by performing a roughening treatment on the surface of the copper foil in a wet manner as follows. First, a copper composite compound containing copper oxide (second copper oxide) as a main component is formed on the surface of the copper foil by oxidation treatment on the surface of the copper foil by a wet method. As a result, a "fine concavo-convex structure formed by a convex portion of a needle shape or a plate shape" formed of a copper composite compound containing copper oxide as a main component can be formed on the surface of the copper foil. Thereafter, if necessary, a portion of the copper oxide is converted into cuprous oxide (oxidized first copper) by subjecting the copper compound to a reduction treatment, and a copper oxide and cuprous oxide are formed on the surface of the copper foil. A fine concavo-convex structure formed by a convex portion of a needle shape or a plate shape formed by a copper composite compound. Here, the "fine concavo-convex structure" referred to in the present application is formed of a copper compound containing copper oxide at the stage of oxidizing the surface of the copper foil. Therefore, in the case of forming a fine concavo-convex structure mainly composed of copper oxide or a fine concavo-convex structure formed of copper oxide, it is not necessary to carry out a reduction treatment after the oxidation treatment, and the roughening treatment may be completed. On the other hand, in the case where a fine uneven structure containing cuprous oxide is formed in a certain ratio, the reduction treatment may be carried out. Even if the reduction treatment is applied, a part of the copper oxide can be converted into cuprous oxide in a shape in which the fine concavo-convex structure formed by the copper compound mainly composed of copper oxide is maintained. The result can be formed by A "fine concavo-convex structure" formed of a copper composite compound of copper oxide and cuprous oxide. In this way, after the surface of the copper foil is subjected to an appropriate oxidation treatment by a wet method, if necessary, a reduction treatment is performed as necessary, and the formation of the above-mentioned "fine concavo-convex structure" becomes possible. Further, a copper composite compound containing copper oxide as a main component or a copper composite compound containing copper oxide and cuprous oxide may contain a small amount of metallic copper.

For example, when the roughening treatment is carried out by the wet method described above, it is preferred to use an alkaline solution such as a sodium hydroxide solution. By oxidizing the surface of the copper foil with an alkaline solution, a convex portion formed of a copper composite compound containing copper oxide as a main component in a needle shape or a plate shape can be formed on the surface of the copper foil. Here, when the surface of the copper foil is oxidized by the alkaline solution, the convex portion grows long, and when the maximum length exceeds 500 nm, it is difficult to form the fine concavo-convex structure referred to in the present application. Therefore, in order to form the fine concavo-convex structure, it is preferable to use an alkaline solution containing an oxidation inhibitor capable of suppressing oxidation of the surface of the copper foil in order to form the fine concavo-convex structure.

As such an oxidation inhibitor, for example, an amino silane coupling agent can be mentioned. If an alkaline solution containing an amino decane coupling agent is used and an oxidation treatment is applied to the surface of the copper foil, the amino decane coupling agent in the alkaline solution is adsorbed on the surface of the copper foil, and the surface of the copper foil caused by the alkaline solution can be suppressed. Oxidation. As a result, growth of needle crystals of copper oxide can be suppressed, and an extremely fine uneven structure can be formed on the surface of the copper layer.

As the above decane coupling agent, specifically, N-2-(aminoethyl)-3-aminopropylmethyldimethoxydecane, N-2-(aminoethyl)-3-aminopropyl group can be used. Trimethoxy decane, 3-aminopropyltrimethoxy decane, 3-aminopropyl triethoxy Decane, 3-triethoxyoxane-N-(1,3-dimethyl-butylene)propylamine, N-phenyl-3-aminopropyltrimethoxydecane, and the like. These are all dissolved in an alkaline solution, and can be stably held in an alkaline solution while exerting an effect of suppressing oxidation of the surface of the copper foil.

As described above, the fine concavo-convex structure formed by subjecting the surface of the copper foil to an oxidation treatment by an alkaline solution containing an amino-based decane coupling agent can be almost maintained even after the reduction treatment. As a result, a roughened surface having a fine concavo-convex structure formed of a needle-like or plate-like convex portion having a maximum length of 500 nm or less formed of a copper composite compound containing copper oxide and cuprous oxide can be formed. . In the reduction treatment, the Cu(I) wave obtained when the constituent elements of the copper composite compound having a fine uneven structure is formed by qualitative analysis using XPS can be appropriately adjusted by adjusting the concentration of the reducing agent, the pH of the solution, the temperature of the solution, and the like. The total area of the front area and the Cu(II) peak area, and the peak area occupied by Cu(I). Further, for example, by immersing the copper foil in an alkaline solution, a fine concavo-convex structure containing copper oxide as a main component is formed on both surfaces of the copper foil, and then, only the adhesion surface to the surface of the insulating layer constituent material is subjected to reduction treatment. It is possible to make a double-sided roughening copper foil with a peak occupancy ratio of Cu(I) of the laser irradiation surface Cu(I) of 0% or less than 2%, and a crest occupancy ratio of Cu(I) of 50% or more with respect to the adhesion surface. . Further, the occupation ratio of the peak of Cu(I) on both sides can be appropriately adjusted. When the constituent elements of the fine concavo-convex structure formed by the above method are analyzed by XPS, the presence of "-COOH" is detected.

Since the oxidation treatment and the reduction treatment described above can be carried out by a wet method using each treatment solution, the above-mentioned fine unevenness can be easily formed on both sides of the copper foil by immersing the copper foil in a treatment solution or the like. Structure Made. Therefore, when the wet method is used, the fine concavo-convex structure is formed on both surfaces of the copper foil, and the laser drilling processability on the laser irradiation surface side can be improved, and the anchoring structure can be anchored by the fine concavo-convex structure. The effect is that the insulating layer constituent material and the copper foil have good adhesion. In addition, as described above, the fine concavo-convex structure has high scratch resistance, and even if the fine concavo-convex structure is formed on both surfaces of the copper foil, the operation is easy, and the fine concavo-convex structure on the surface of the laser irradiation surface side can be maintained. It can prevent falling powder and the like.

1-3. Treatment with decane coupling agent

The decane coupling agent layer may be provided on the adhesion surface of the insulating layer constituent material of the two-side roughened copper foil in order to improve the moisture absorption deterioration resistance when processed into a printed circuit board. The decane coupling agent treatment layer disposed on the roughening treatment surface may be formed by using any one of an olefin functional decane, an epoxy functional decane, an ethylene functional decane, an acrylic functional decane, an amino functional decane, and a decyl functional decane as a decane coupling agent. . These decane coupling agents are represented by the general formula R-Si(OR')n (here, R: an organic functional machine represented by an amino group or a vinyl group, OR': a methoxy group or an ethoxy group) Representative of the hydrolysis base, n: 2 or 3.).

The decane coupling agent as used herein, more specifically, refers to the same decane coupling agent as the glass cloth used for the prepreg for printed circuit boards, and vinyl trimethoxy decane or vinyl can be used. Phenyltrimethoxydecane, γ-methacryloyltrimethoxydecane, γ-glycidoxytrimethoxydecane, 4-butyl glycidyl ether trimethoxydecane, γ-aminopropyltriethoxy矽, N-β(aminoethyl)γ-aminopropyltrimethoxydecane, N-3-(4-(3-aminoprop)butyl)propyl-3-aminopropyltrimethoxydecane, imidazolium , triazine decane, 3-acryloyl methoxy decane, γ-mercaptopropyl trimethoxy decane, and the like.

The decane coupling agents listed herein do not adversely affect the characteristics after becoming a printed circuit board. Which one of the decane coupling agents is used can be appropriately selected depending on the use of the copper clad laminate or the like.

The decane coupling agent described above is preferably a water-based solvent, and the decane coupling agent component is contained in a concentration range of 0.5 g/L to 10 g/L, and a decane coupling agent treatment liquid having a temperature of room temperature is preferred. When the concentration of the decane coupling agent of the decane coupling agent treatment liquid is less than 0.5 g/L, the susceptibility of the decane coupling agent is slow, which does not conform to the general commercial standard, and the adsorption becomes uneven. On the other hand, when the concentration of the decane coupling agent exceeds 10 g/L, the adsorption rate does not become particularly high, and there is no possibility that the performance quality such as moisture absorption deterioration resistance is particularly improved, which is not economically preferable.

The adsorption method of the decane coupling agent for the roughened surface by using the decane coupling agent treatment liquid may be a dipping method, a shower method, a spray method, or the like, and is not particularly limited, that is, as long as the engineering design is used, the coarsening can be performed. The method of contacting and adsorbing the treatment surface with the decane coupling agent treatment liquid most uniformly can be carried out.

After the decane coupling agent is adsorbed on the roughened surface, sufficient drying is carried out to promote the condensation reaction between the -OH group of the roughened surface and the adsorbed decane coupling agent, so that the moisture generated by the condensation is completely evaporated. . The drying method at this time is not particularly limited. For example, an electric heater or an air blowing method for blowing warm air may be used, and it is not particularly limited, and a drying method and a drying condition corresponding to the manufacturing line may be employed. However, the decane coupling agent treatment described above is not required to be applied to the laser irradiation surface for the treatment with the bonding surface of the insulating layer constituent material.

1-4. The brightness of the roughened surface L*

As described above, the needle-like or plate-like convex portion having the maximum length of the fine concavo-convex structure of 500 nm or less is shorter than the wavelength of the carbon dioxide gas laser and is arranged at a shorter distance from the wavelength range of the visible light. The light incident on the roughened surface is attenuated as a result of repeating the disordered reflection in the fine concavo-convex structure. That is, the roughened layer acts as a light absorbing surface, and the surface of the roughened surface is darkened to become blackish or brownish as compared with before the roughening treatment. That is, the copper-clad laminate associated with the present application has a characteristic color tone on the roughened surface of the surface, and the value of the brightness L* in the L*a*b* color system is 30 or less. When the value of the luminance L* exceeds 30 and the color tone is bright, it is not preferable that the maximum length of the convex portion constituting the fine concavo-convex structure exceeds 500 nm. Further, when the value of L* exceeds 30, even if the maximum length of the convex portion is 500 nm or less, the convex portion may not be sufficiently densely formed on the surface of the copper foil. Thus, if the value of the brightness L* exceeds 30, it is considered that the roughening process is insufficient or the state of the roughening process is not uniform. In this case, it is not preferable to perform insufficient roughening treatment in order to obtain good laser drilling performance, scratch resistance, and good adhesion to the insulating layer constituent material. Further, the value of the luminance L* is preferably 25 or less. When the value of the brightness L* is 25 or less, it becomes a roughening treatment surface which is more suitable for laser drilling. In addition, the measurement of the brightness L* was performed by a spectrophotometer SE2000 manufactured by Nippon Denshoku Industries Co., Ltd., and the brightness was corrected using a white plate attached to the measuring device according to JIS Z8722:2000. Then, the measurement was performed three times on the same portion, and the average value of the measurement data of the brightness L* of three times was taken as the value of the brightness L* indicated in the present application. Further, even if the above-described decane coupling agent treatment is applied to the roughened surface, the value of the brightness L* of the roughened surface does not fluctuate after the decane coupling agent treatment.

1-5. Layer composition of copper clad laminate

The specific layer constitution of the copper clad laminate 1 relating to the present application will be described. The copper clad laminate includes, for example, a basic layer configuration as shown in Figs. 3 and 4. 3 is a view showing an example of a layer configuration when the roughened surface 4 on the deposition surface side of the electrolytic copper foil 2 is an outer surface and used as a laser irradiation surface, and FIG. 4 is an electrode surface of the electrolytic copper foil 2. The side roughening treatment surface 3 is an outer layer surface of the copper clad laminate, and is used as a layer constitution example when the laser irradiation surface is used. In either case, the roughened surface on the other side is the surface of the insulating layer. Further, as shown in FIGS. 3 and 4, the laser opening referred to in the present application may be laminated on the opposite side (the other surface) of the irradiation side of the laser light on the copper clad laminate. Roughening copper foil for processing. The case where the rolled copper foil is used instead of the electrolytic copper foil is also the same as these. In either case, the two-side roughened copper foil may be laminated on at least one side of the insulating constituent material. By adopting this configuration, the laser-illuminated surface of the copper-clad laminate 1 can be used as the present application. Refers to the roughening treatment surface. As described above, if the fine uneven structure is provided on the laser irradiation surface, the roughened surface acts as a laser light absorbing surface, and thus it is easy to perform laser drilling. Further, if the other side of the copper clad laminate 1 is not used as the laser irradiation surface, the copper layer on the other side may have any configuration. However, by laminating a copper foil having the above-described fine concavo-convex structure as an insulating layer constituent material, as described above, good adhesion to the insulating layer constituent material can be obtained.

Further, as shown in FIGS. 3 and 4, the insulating layer 5 is present between the copper layer 2 having the laser irradiation surface and the copper layer 2 on the other surface side. The insulating layer 5 is a layer formed of a material constituting an insulating layer such as a resin, and is not limited to the insulating layer constituting material.

2. The basic concept of laser drilling method

Next, a method of performing laser drilling processing using the above-described copper clad laminate will be described with reference to FIG. Here, a case where the copper-clad laminate having the same layer configuration as that shown in Fig. 3 (1-C) is subjected to laser drilling is described as an example. In the present application, when the laser drilling process is performed, the roughened surface 4 is used as a laser irradiation surface, and the roughened surface 4 is irradiated with laser light such as a carbon dioxide gas to form a laser beam. The blind via 10 as shown in Fig. 5(B). At this time, by adjusting the irradiation time of the laser light or the like, it is possible to penetrate the through-holes on the other surface side of the laser irradiation surface. In this case, in the fifth diagram (B), the copper layer 2 on the opposite side of the irradiation side of the laser light is the surface on the irradiation side of the laser light of the copper layer 2. In other words, the surface of the surface which is in contact with the insulating layer 5 is a roughened surface 3 having a fine concavo-convex structure formed of a needle-like or plate-like convex portion having a maximum length of 500 nm or less formed of a copper composite compound. In addition, the processing performance of the laser opening when the through hole is formed can be improved.

Here, it is attempted to consider the reason why the laser drilling process performance can be improved by making the laser irradiation surface in the present application the roughened surface. First, by using the outer surface of the copper layer as the roughened surface, the outer surface of the copper layer has a fine uneven structure. As described above, since the roughened surface becomes a rough surface of black or brownish brown, the laser light is suppressed. The reflection is so that the thermal energy of the laser light can be efficiently supplied to the laser light irradiation portion. On the other hand, in the case where the laser irradiation surface of the copper clad laminate is the copper layer itself, if the surface of the copper layer is not subjected to roughening treatment or blackening treatment, the laser light is reflected on the surface of the copper layer. The thermal energy of the laser light cannot be efficiently supplied to the laser light irradiation portion.

Further, with respect to the boiling point of copper of 2562 ° C, the boiling points of copper oxide and cuprous oxide are 2000 ° C and 1800 ° C, respectively, and the boiling points of copper oxide and cuprous oxide are lower than those of copper. Therefore, if the laser light is applied to the roughened surface, the laser irradiation portion of the roughened surface quickly reaches the boiling point as compared with the case where the copper layer itself is the outer surface. On the other hand, the thermal conductivity relative to copper is 354 W at 700 ° C. m ^-1 . The thermal conductivity of K ^-1 , copper oxide and cuprous oxide is 20W at 700 ° C. m ^-1 . K ^-1 or less. That is, the thermal conductivity of copper oxide and cuprous oxide is one tenth or less of the thermal conductivity of copper. On the other hand, the melting points of copper oxide and cuprous oxide are 1201 ° C and 1235 ° C, respectively, and the melting point of copper is as low as 1083 ° C. Therefore, in the case where the roughened surface is irradiated with the laser light, compared with the case where the copper layer itself is the outer surface, the speed of heat transfer is performed on the outer side of the laser irradiation portion when the roughened surface is irradiated with the laser light. Slow down. As a result, heat can be concentrated in the depth direction, and the temperature of the copper layer can be easily made higher than the melting point. Therefore, by having the fine concavo-convex structure formed of the copper composite compound on the laser irradiation surface, the laser drilling process can be efficiently performed compared to the case where the copper layer itself is the outer surface.

In addition, in the fifth drawing, the case where the copper-clad laminate 1 having the layer configuration shown in Fig. 3 (1-C) is subjected to laser drilling is described, but the third and fourth drawings are provided. In the copper-clad laminate 1 or the like of any of the layer structures shown, if the copper layer of the laser-illuminated surface of the copper-clad laminate is formed by using the two-side roughened copper foil referred to in the present application, even if it has other layers The copper clad laminate formed may be subjected to laser drilling in the same manner as described above.

<Form of printed circuit board>

The printed circuit board relating to the present application is characterized by including a copper layer formed by using a roughened copper foil for laser drilling, for example, for use. A printed circuit board manufactured by laminating copper laminates related to the present application. Further, the printed circuit board according to the present application may have a copper layer formed by using the above-described two-side roughening copper foil, and may be, for example, a multilayer manufactured by the processes shown in FIGS. 6 and 7. The printed circuit board is not limited to the multilayer printed circuit board described below, and the specific layer configuration, manufacturing method, and the like are not particularly limited.

The sixth and seventh drawings show an example of a manufacturing process of a multilayer printed circuit board by a so-called build-up method. For example, as shown in Fig. 6(A), on both sides of the inner layer substrate 9 having the inner layer circuit 8, the insulating layer constituent material 7 such as a prepreg or a resin film is laminated, and the above is related to the present application. The copper foil is roughened on both sides. Further, in the example shown in Fig. 6(A), the inner laminated board 9 is exemplified, and the inner layer circuit 8 is provided on both sides thereof to form a layer in which the via hole (via) 10 is indirectly continued. However, the inner laminate 9 is not limited to the embodiment shown in Fig. 6(A), and the layer configuration and the like may be arbitrary.

As described above, when the two surfaces of the inner laminated board 9 are laminated on the insulating layer forming material 7 to laminate the two-side roughened copper foil referred to in the present application, the first build-up layer 30 is formed on both surfaces of the inner layer substrate 9. The first laminate 40 having a buildup layer (see Fig. 6(B)). Then, the roughened surface 4 of the first buildup layer 30 is irradiated with laser light, for example, by laser drilling in the same manner as described above. Thereafter, in order to remove the desmear treatment of the resin residue generated by the laser drilling process, the inner wall portion of the via hole is subjected to interlayer conduction plating treatment to form the plating layer 24, and the via hole is plated. Fill as a filling guide hole. Then, the first build-up wiring layer 31 is formed by etching, and the first build-up circuit layer laminate 41 having the via holes 10 for connecting to the inner layer circuit of the inner substrate 9 is formed (see the seventh). Figure (C)).

Further, on both surfaces of the first multilayered layered laminated body 41 shown in Fig. 7(C), the insulating layer forming material 7 such as a prepreg or a resin foil film is laminated and roughened on both sides. The copper foil 2 is the second buildup layered body 42 having the second buildup layer 32 shown in Fig. 7(D). At this stage, the same construction as in Fig. 6 (B) and Fig. 7 (C) is applied, and the insulating layer constituent material 7 such as a prepreg or a resin film is placed again, and the two sides are roughened as necessary. The operation of the copper foil 2 can be a build-up substrate having an nth circuit pattern layer (n≧3: integer).

Then, the build-up layer substrate of the final build-up layer is finished, and the plating is performed by performing laser opening processing, removing residual glue treatment, and performing interlayer conduction plating treatment in the via hole to form a plating layer, and plating filling. The guide hole 10 is filled in the guide hole. Thereafter, the outer copper layer is etched or the like to form an outer layer circuit to form a multilayer printed wiring board.

Since the above-mentioned printed circuit board uses the double-faced roughened copper foil related to the present application, the laser drilling performance is good, and it has a good pilot hole as a printed circuit board. Moreover, it is possible to obtain good adhesion to the insulating layer constituent material of the inner layer circuit by the fine concavo-convex structure on the surface side.

Hereinafter, technical advantages in the production of a copper clad laminate and a printed circuit board using the roughened copper foil for laser drilling according to the present application will be described by way of examples and comparative examples.

[Example 1]

As the electrolytic copper foil, the surface roughness (Rzjis) of the deposition surface was 3.2 μm, the surface area ratio (B) was 1.2, the gloss [Gs (60°)] was 2, and the surface roughness (Rzjis) of the electrode surface was 1.2μm, surface area ratio (B) is 1.05, gloss [Gs (60°)] is 110 An electrolytic copper foil having a thickness of 12 μm is applied to the deposition surface and the electrode surface. The surface treatment was applied in the following procedure. Further, the method of measuring the surface roughness, the surface area ratio, and the gloss is as follows.

[Measurement of thickness]

The surface roughness was measured in accordance with JIS B 0601-2001 using a probe type surface roughness meter SE3500 manufactured by Otaru Laboratory.

[Measurement of surface area ratio]

Using the stock company KEYENCE laser microscope VK-X1000, the surface area ratio (B) was determined according to the above calculation formula based on the surface area A when the field of the secondary region of 57570 μm ² was measured by a laser method.

[Measurement of gloss]

Glossiness was measured by JIS Z 8741-1997, which is a method for measuring glossiness, using a gloss meter PG-1M type manufactured by Nippon Denshoku Industries Co., Ltd.

This electrolytic copper foil was subjected to a preliminary treatment and then subjected to a roughening treatment. The following is explained in order.

Preparation treatment: The electrolytic copper foil was immersed in an aqueous sodium hydroxide solution, subjected to alkaline degreasing treatment, and washed with water. Then, the electrolytic copper foil after completion of the alkaline degreasing treatment was immersed in a sulfuric acid-based aqueous solution having a sulfuric acid concentration of 5 mass% for 1 minute, and then washed with water.

Roughening treatment: The electrolytic copper foil after the completion of the preliminary treatment is subjected to an oxidation treatment. Oxidation treatment, at a liquid temperature of 70 ° C, pH = 12, containing chlorous acid concentration of 150g / L, N-2-(aminoethyl)-3-aminopropyltrimethyl decane concentration of 10g / L of hydration In the sodium solution, the electrolytic copper foil is immersed for a predetermined oxidation treatment time (1 minute, 2 minutes, 4 minutes, 10 minutes) to obtain copper in the electrolytic solution. Each of the two sides of the foil has four kinds of samples each having a fine concavo-convex structure composed of a copper composite compound containing copper oxide as a main component.

Next, the four types of samples after the completion of the oxidation treatment were subjected to a reduction treatment. In the reduction treatment, each sample after completion of the oxidation treatment was immersed in an aqueous solution (room temperature) having a concentration of dimethylamine borane of 20 g/L adjusted to pH=12 with sodium carbonate and sodium hydroxide for 1 minute to carry out reduction. Treatment, washing and drying. By the above-mentioned process, a part of the copper oxide on both surfaces of the electrolytic copper foil is reduced to form cuprous oxide, and the roughening structure having a fine concavo-convex structure formed of a copper composite compound containing copper oxide and cuprous oxide is formed. surface. According to the above-described work, it is possible to obtain four types of roughened copper foil for laser opening processing in which four kinds of fine concavo-convex structures are provided on both sides in accordance with the present application.

Then, for the roughening treatment surface of the two-side roughening copper foil for the above four types of laser opening processing, qualitative analysis is performed using XPS, and the wave front area of Cu(I) and the wave front of Cu(II) are obtained. The area ratio of the wave front area of Cu(I) of the total area of the area. Moreover, as a result of this qualitative analysis, the presence of the "-COO group" on the roughened surface was also clearly confirmed. Further, the Kr adsorption specific surface area and the luminance L* of the roughened copper foil obtained in this example are shown in Table 1 below. In addition, in Table 1, "Kr adsorption specific surface area" is only shown as "specific surface area."

Then, the peel strength was measured for the above four types of samples in which the copper composite compound was formed on both surfaces. In the measurement, each sample was placed on an FR-4 prepreg (R1551 manufactured by Panasonic Corporation) of an insulating component, and a vacuum press was used at a pressurization pressure of 2.9 MPa, a temperature of 190 ° C, and a press time of 90 minutes. The conditions are laminated to produce a copper clad laminate. Then use this overlay A copper laminated plate was subjected to an etching method to prepare a test substrate having a linear circuit for measuring a peel strength of 3.0 mm. Then, the peel strength was measured for each sample in accordance with JIS C6481 (1996).

[Example 2]

In the second embodiment, the electrolytic copper foil which is the same as in the first embodiment is formed into a fine concavo-convex structure including a convex portion formed of a copper composite compound containing copper oxide as a main component on one surface in accordance with the following procedure. The surface of the roughened surface includes a roughened copper foil having a roughened surface having a fine uneven structure formed of a convex portion formed of a copper composite compound of copper oxide and cuprous oxide, and the two surfaces are roughened. The other side of the roughened copper foil was laminated on the insulating layer constituent material to form a copper clad laminate. Since the preliminary treatment and the oxidation treatment (roughening treatment) of the above-mentioned electrolytic copper foil are carried out in the same manner as in the first embodiment, the description thereof will be omitted here, and the construction after the reduction treatment after the oxidation treatment will be described.

Roughening treatment (reduction treatment): As described above, the electrolytic copper foil subjected to the preliminary treatment and the oxidation treatment (oxidation treatment time of 2 minutes) in the same manner as in Example 1 was subjected to reduction treatment as follows. In the second embodiment, the reduction treatment was carried out in the same manner as in the first embodiment except that the reduction treatment was applied to the side of the laser irradiation surface, and only the surface on the side of the adhesion surface of the insulating layer was used.

Treatment with decane coupling agent: Then, the surface subjected to the reduction treatment, that is, the surface of the material constituting the insulating layer, is treated with a decane coupling agent. Specifically, after the reduction treatment, the water is washed, and the decane coupling agent treatment liquid (aqueous solution containing γ-glycidoxytrimethoxydecane having a concentration of 5 g/L in ion-exchanged water as a solvent) is blown by a shower method. The adsorption of the decane coupling agent is carried out on the surface where the above reduction treatment is carried out. Then, after the adsorption of the decane coupling agent is completed, use The electric heater evaporates the surface water in an atmosphere at an atmospheric temperature of 120 ° C to promote the condensation reaction of the -OH group and the decane coupling agent on the roughened surface.

A copper clad laminate was produced in the same manner as in Example 1 except that the copper foil was roughened on both sides obtained in the above work. Then, a test substrate was produced in the same manner as in Example 1, and the peel strength was measured.

[Comparative example]

[Comparative Example 1]

In Comparative Example 1, the conventional blackening treatment was applied to both surfaces of the electrolytic copper foil similar to the electrolytic copper foil used in Example 1, and the fine copper oxide was adhered to a dark brown state. The blackening treatment conditions at this time were 25 g/L of sodium chlorite, 20 g/L of sodium hydroxide, 6 g/L of an alkyl ester, a liquid temperature of 67 ° C, and a treatment time of 4 minutes. Electrolytic copper foil (hereinafter referred to as "two-faced blackened copper foil") subjected to blackening treatment on both surfaces thereof was laminated on both sides of the above-mentioned FR-4 prepreg under the same conditions as in Example 1. , to obtain a copper clad laminate.

[Comparative Example 2]

In the comparative example, the conventional blackening treatment and reduction treatment (reduction blackening treatment) were applied to both surfaces of the electrolytic copper foil similar to the electrolytic copper foil used in Example 1. At this time, the blackening treatment conditions were as follows: "PRO BOND 80A OXIDE SOLUTION" 10 vol% and "PRO BOND 80B OXIDE SOLUTION" 20 vol% aqueous solution containing the oxidation treatment liquid of Rohm and Haas Electronic Materials Co., Ltd., liquid temperature 85 ° C, Processing time is 5 minutes. Then, the electrolytic copper foil subjected to the blackening treatment was subjected to a reduction treatment under the following reduction treatment conditions. The reduction treatment conditions were 6.7 vol% using "CIRCUPOSIT PB OXIDE CONVERTER 60C" containing a reducing treatment liquid manufactured by Rohm and Haas Electronic Materials Co., Ltd. "CUPOSITZ" 1.5 vol% aqueous solution, liquid temperature 35 ° C, treatment time 5 minutes. An electrolytic copper foil (hereinafter referred to as "double-sided reduction blackening copper foil") subjected to reduction blackening treatment on both surfaces thereof was laminated on the above-mentioned FR-4 prepreg under the same conditions as in Example 1. On both sides, a copper clad laminate is obtained.

Table 1 below shows the specific surface area, the brightness L*, and the peel strength of the four-side roughened copper foil for laser opening processing in which four types of fine concavities and convexities are provided on both surfaces, which are obtained in the first and second embodiments. Each measurement result. Further, the occupancy area ratio (%) of the Cu(I) peak when the constituent elements of the copper composite compound were qualitatively analyzed by XPS was used. Further, Table 1 shows the results of measurement of the specific surface area, the brightness L*, and the peel strength of the two-faced blackened copper foil obtained in Comparative Example 1 and Comparative Example 2 and the two-faced blackened reduction copper foil.

As can be understood from Table 1, even if the oxidation treatment time is changed from 1 minute to 10 minutes, the maximum length of the fine unevenness formed on both the deposition surface and the electrode surface is 500 nm or less, and qualitative analysis on the roughened surface. Central There is no difference in the content checked out. Further, regarding the value of the brightness L* of the roughened surface, a value having a small difference of 18 to 26 is also displayed. On the other hand, the Kr adsorption specific surface area is proportional to the increase in the oxidation treatment time, and the value becomes large. Then, in the four types of laser drilling, the peeling strength of the copper foil treated by the two-side roughening treatment can obtain a practically sufficient peeling strength even in the shortest oxidation treatment time, and the value of the specific surface area to be adsorbed with Kr can be obtained. It is proportional to the peel strength. From this point of view, it can be understood that the oxidation treatment time employed in the examples is an appropriate time.

Next, a review of the processing performance of the laser opening. In the embodiment and the second embodiment, the copper foil for double-face roughening treatment for laser hole drilling according to the present application is used, and a needle-like or plate-like shape having a maximum length of 500 nm or less formed of a copper composite compound is used. A copper clad laminate having a roughened surface of a fine concavo-convex structure formed by a convex portion. On the other hand, in Comparative Example 1, the electrolytic copper foil subjected to the conventional blackening treatment was laminated on the insulating layer constituent material, and in Comparative Example 2, the electrolytic copper foil layer subjected to the conventional reduction blackening treatment was used. The material that is accumulated in the insulating layer. Then, using a filter paper (No. 5B), the laser-illuminated surface of the copper-clad laminate which is related to the embodiment and the copper-clad laminate which is related to the comparative example was gently rubbed by hand, and as a result, with Example 1 and The roughened surface of the copper clad laminate according to Example 2 was not changed by visual observation. On the other hand, the blackened surface or the reduced blackened surface of the copper-clad laminate according to Comparative Example 1 and Comparative Example 2 produced gloss. The surface rubbed with the filter paper is used as a laser irradiation surface to perform the drilling process.

At this time, the carbon dioxide gas irradiation conditions are predetermined to have a mask diameter of 2.3 mm, a pulse width of 14 μsec, a pulse energy of 15.0 mJ, a displacement of 0.8, and a laser beam diameter of 124 μm, for the use of laser aperture processing for two-sided roughening treatment. Copper foil The copper-clad laminate was formed into a hole having a processing diameter of 80 μm, and a pilot hole formation test was performed for each sample 100. Therefore, as a criterion for judging by the inventors and the like, the pore diameter after the processing is in the range of 80 μm or more, and it is judged that the processing is performed satisfactorily. Hereinafter, the results are shown in Table 2 below.

As can be seen from Table 2, the results of the laser drilling performance of the double-faced roughened copper foil for the laser drilling process were investigated. In the case of the first and second embodiments, it was judged that all the samples were in good condition. The mine is shot open. On the other hand, in the case of Comparative Example 1 and Comparative Example 2, the opening ratio was 40% due to the gloss caused by friction on the blackened surface or the reduced blackened surface, and it is understood that the open pore size distribution is large. Amplitude. That is to say, it can be said that the laser drilling process has not been achieved. In addition, the opening ratio referred to in Table 2 refers to the ratio of the number of shots that can be opened by performing a pilot hole formation test of 100 shots. Then, the opening pore size distribution is measured when the opening diameter of the pilot hole obtained in the 100-well conducting hole formation test is measured. The extent of the distribution.

[Industrial Availability]

By using a roughened copper foil for laser hole drilling processing according to the present application, a copper clad laminate or a printed circuit board is produced, and the laser absorbance is high and the scratch resistance is excellent. The roughened surface of the fine concavo-convex structure formed by the compound is used as the outer surface of the copper layer. Therefore, it is possible to exhibit the same performance as the laser drilling process when the surface of the copper layer is subjected to the conventional blackening treatment, and the worker does not need to pay careful attention when operating the copper-clad laminate, and the work efficiency is obtained. Upgrade. As a result, the difference in the processing performance of the laser opening of the copper clad laminate is reduced, and the opening of the stability becomes possible. At the same time, good adhesion to the insulating layer constituent material can be obtained, and the difference in adhesion between the two in the surface can be prevented. Moreover, a good etching factor can be obtained. In particular, the roughened copper foil for laser hole drilling is suitable for use in a build-up method of a printed circuit board, and a multilayered layer can be provided by using the roughened copper foil to form a build-up layer. Circuit board.

2‧‧‧ copper foil

4‧‧‧The roughening surface of the surface

7‧‧‧Insulation layer

8‧‧‧ Inner layer circuit

10‧‧‧ Guide hole

23‧‧‧1st build-up wiring circuit

24‧‧‧Electroplating

30‧‧‧1st build-up

31‧‧‧1st build-up circuit layer

32‧‧‧2nd layer

41‧‧‧Layer with the first build-up circuit layer

42‧‧‧Layer with second build-up

Claims (13)

A roughened copper foil for laser hole drilling, characterized in that: on both sides of the copper foil, a needle-like or plate-like convex shape having a maximum length of 500 nm or less formed by a copper composite compound containing copper oxide is included The roughened surface of the fine concavo-convex structure formed by the shape is one surface of the copper foil which is a laser irradiation surface irradiated with laser light during laser processing, and the other surface is a surface of the insulating layer. The roughened copper foil for laser hole drilling according to the first aspect of the patent application, wherein the Cu(I) obtained by analyzing the constituent elements of the roughened surface by X-ray photoelectron spectroscopy The area of the wave front, the total area of the wave front area of Cu(II), and the ratio of the wave front area of Cu(I), the side of the laser irradiation surface is less than 50%, and the side of the above-mentioned surface is 50% or more. . The roughened copper foil for laser drilling according to the first aspect of the invention, wherein the laser irradiation surface has the fine concavo-convex structure formed of a copper composite containing copper oxide as a main component, and the The surface side has the above-described fine concavo-convex structure formed of a copper composite oxide containing cuprous oxide as a main component. The roughened copper foil for laser drilling according to the first aspect of the invention, wherein the roughened surface is observed at a magnification of 45° or more and a magnification of 50,000 times or more by using a scanning electron microscope Among the convex portions, the length of the tip end portion which is separable from the other convex portions is 250 nm or less. The roughened copper foil for laser hole drilling according to the fourth aspect of the patent application, wherein the convex portion is formed for the maximum length of the convex portion The length of the aforementioned tip end portion is 1/2 or less. The roughened copper foil for laser drilling according to the first aspect of the invention, wherein the specific surface area measured by adsorbing ruthenium on the surface of the roughened layer is 0.035 m ² /g or more. The roughened copper foil for laser opening processing according to the first aspect of the invention is characterized in that the brightness L* when the roughening treatment layer is expressed by the L*a*b* color system is 30 or less. The roughened copper foil for laser hole drilling according to the first aspect of the patent application, wherein the surface area of the laser irradiation surface side of the copper foil measured by a laser method in the secondary region of 57570 μm ² is referred to as three times. The element surface area (Aμm ² ), when the ratio of the three-dimensional surface area of the area of the above-mentioned secondary element is B, B is 1.1 or more. The roughened copper foil for laser hole drilling according to the first aspect of the invention, wherein the copper foil has a surface roughness (Rzjis) of 2.0 μm or less. The roughened copper foil for laser hole drilling according to the first aspect of the patent application, wherein the ruthenium coupling agent treatment is applied to the subsequent surface. A copper clad laminate characterized in that the roughened copper foil for laser opening processing of the first application of the patent application is laminated on at least one surface of the insulating layer constituent material. A printed circuit board comprising a copper layer formed by using a roughened copper foil for laser opening processing according to claim 1 of the patent application. The printed circuit board according to claim 12, wherein the copper layer and the insulating layer have via holes formed by laser drilling.