TWI589433B - Copper foil with carrier foil, copper clad laminate, and printed circuit board - Google Patents

Description

Copper foil with carrier foil, copper clad laminate, and printed circuit board

The present application relates to a copper foil, a copper clad laminate, and a printed circuit board having a carrier foil.

With the recent years of mobile phones, mobile tools, notebook PCs and other lightweight. The popularity of miniaturization requires even the same thin, short, and high-density packaging for printed circuit boards assembled on these electronic devices. In order to cope with the thinness and high density of such a printed circuit board, a multilayer printed circuit board is used.

The multilayer printed circuit board has a plurality of conductor layers which are electrically connected between the conductor layers by interlayer conduction means such as through holes. Further, in recent years, in order to cope with further high-density mounting and fine wiring, a via hole is used as an interlayer conduction means instead of a via. The through hole is formed by drilling in general, and the via hole is formed by laser processing. Therefore, when compared with the through hole, the diameter of the via hole is smaller than that of the through hole, and the high density structure is changed. It is beneficial. As the via hole of the interlayer conduction means, various forms such as a blind via (BVH), a mesoporous via (IVH), and a stacked via are known.

In order to form the via holes, it is necessary to irradiate the laser light in a conductor layer composed of a copper foil or the like. Copper foil is generally mirrored and reflects laser light. Therefore, it is not easy to perform laser drilling. Therefore, the laser light irradiation surface is required to have good laser drilling performance. In addition, during laser drilling, the phenomenon of splashing of the scattered dripping occurs around the opening. When the splashing phenomenon occurs, the portion to which the drip adheres is formed around the opening. Therefore, when the copper plating layer is formed after the drilling process, the plating layer is abnormally precipitated in the portion where the projection is formed, and the failure of the required circuit or the like occurs. Therefore, when the via hole is formed by laser processing, it is necessary to prevent the adhesion of the drip caused by the splash phenomenon.

As a technique for considering the phenomenon of splashing, Patent Document 1 discloses that "a double-sided printed circuit board or a method of manufacturing a multilayer printed circuit board of three or more layers requires a double-layer copper plating plating such as a via hole or a via hole. A method for manufacturing a surface printed circuit board or a multilayer printed circuit board of three or more layers, characterized in that a copper foil with a carrier foil in a peelable type is used in a copper foil located on the outer layer of the printed circuit board, and no peeling carrier is used. The foil is subjected to a necessary processing for the through hole for the through hole or the hole for the via hole, and the desiccant for the through hole for the through hole or the hole for the via hole is treated to ensure the through hole or the via hole for the through hole. The interlayer conduction copper plating is performed by electrically conducting the holes, and then the carrier foil is peeled off, and the copper foil in the outer layer is placed, and the outer layer circuit pattern is resisted and etched.

As disclosed in Patent Document 1, if the laser drilling process is performed before the carrier foil is removed and then the carrier foil is removed, the carrier foil and the drip attached to the periphery of the opening can be removed together.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] WO00/69238

However, as in the aforementioned Patent Document 1, when laser drilling is performed by using a carbon dioxide gas laser and the surface of the carrier foil of the copper foil having the carrier foil located on the outer layer of the multilayer laminated board is used, there is The more the thickness of the carrier foil is increased, the more the laser drilling performance is lowered, and the tendency to obtain the via hole having the target opening diameter cannot be obtained.

Therefore, as in Patent Document 1, it is required to perform laser drilling in a state where drilling is performed by using a carbon dioxide gas laser and starting from a surface of a carrier foil of a copper foil having a carrier foil on the outer layer of a multi-layer laminate. A material with good processing properties.

Then, the inventors of the present invention conducted a thorough study, and found that a good laser drilling process can be performed when the copper foil with a carrier foil described below is used. In the following, an outline of the invention of the present application will be described.

<copper foil with carrier foil>

The copper foil with a carrier foil of the present application is a copper foil provided with a carrier foil having a layer structure of a carrier foil/release layer/whole copper layer, and is characterized in that the copper foil provided with the carrier foil A roughened layer having a fine concavo-convex structure formed of a needle-like or plate-like convex portion composed of a copper composite compound and having a maximum length of 500 nm or less is provided on both surfaces, and is provided on the surface of the carrier foil. The roughening treatment layer is used as a laser light absorbing layer, and the roughening treatment layer provided on the surface of the entire copper layer is used as a roughening treatment layer and an insulating layer construction material. Interlayer.

<Covered copper laminate>

The copper-clad laminate of the present application is characterized in that the bonding layer side of the entire copper layer of the copper foil with a carrier foil of the present application is laminated on at least one side of the insulating layer structural material.

<Printed Circuit Board>

The printed circuit board of the present application is characterized in that the entire copper layer of the copper foil with a carrier foil of the present application is used.

The copper foil with a carrier foil of the present application has a needle-like or plate-like convex portion composed of a copper composite compound and having a maximum length of 500 nm or less on both surfaces of the copper foil provided with the carrier foil. The roughened layer of the fine concavo-convex structure formed is provided. Next, the roughened layer provided on the surface of the carrier foil is used as a laser light absorbing layer, and the roughened layer provided on the surface of the entire copper layer is used as a bonding layer between the roughened layer and the insulating layer material. . When the roughened layer provided on the surface of the entire copper layer is bonded to the insulating layer structural material to form a bonding layer, a copper-clad laminate having a carrier foil is obtained, which is obtained by a copper composite compound. A roughened layer of a fine concavo-convex structure formed by forming a needle-like or plate-like convex portion having a maximum length of 500 nm or less is provided. If the copper clad laminate having the carrier foil is used, good adhesion between the insulating layer structural material and the entire copper layer can be obtained. Further, since the roughened layer provided on the surface of the carrier foil absorbs the laser light, the carrier foil and the entire copper layer can be drilled simultaneously using a laser. Then, it can be present by peeling off and removing the carrier foil after drilling. The splash and carrier foil around the opening of the hole formed by the laser drilling process are removed together to expose the clean overall copper layer. Therefore, the copper foil with a carrier foil of the present application can be suitably used when a multilayer printed wiring board is produced by a build-up method or a coreless build-up method. If the copper foil with the carrier foil is used, it is possible to provide a high-quality printed circuit board in which the adhesion between the copper foil and the insulating layer construction material is good, and the cause of the exclusion exists in the mine. It is caused by splashing around the opening of the hole formed by the drilling process.

1‧‧‧ (with carrier foil) copper clad laminate

2‧‧‧ copper foil

3‧‧‧The roughening surface of the electrode side

4‧‧‧The roughening surface of the surface

5‧‧‧Insulation structural materials

8‧‧‧ Inner layer circuit

9‧‧‧ Inner substrate

10‧‧‧ Field vias (vias)

11‧‧‧ Copper foil with carrier foil

12‧‧‧Side foil

13‧‧‧ peeling layer

14‧‧‧Overall copper layer

23‧‧‧1st build-up wiring circuit

24‧‧‧Electroplating

31‧‧‧1st build-up wiring layer

32‧‧‧2nd build-up wiring layer

40‧‧‧The first buildup layer with carrier foil

41‧‧‧The first layered layered body

42‧‧‧Layer with the first build-up wiring layer

43‧‧‧Second buildup layer with carrier foil

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic cross-sectional view showing the basic layer structure of a copper-clad laminate having a carrier foil of the present application.

Fig. 2 is an observation image of a scanning electron microscope for explaining a form of a roughened layer in the copper foil with a carrier foil of the present application.

Fig. 3 is an observation image of a scanning electron microscope showing a cross section of a roughened layer irradiated with laser light on the surface of the laser drilling method of the present application.

4 is a schematic cross-sectional view showing an image of a laser drilling process at the time of forming a blind via hole using laser light.

Figure 5 is a schematic cross-sectional view showing the manufacturing process for the process of manufacturing a multilayer printed circuit board in the build-up method.

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

Figure 7 is used to display the layering method for displaying a multilayer printed circuit board A schematic cross-sectional view of the manufacturing process of the process.

Fig. 8 is a scanning electron microscope observation of a linear circuit having a circuit width of 8 μm/inter-slice gap width of 8 μm obtained by using a copper foil of a carrier foil for laser drilling processing obtained in Example 1. image.

Hereinafter, the "formation of a copper clad laminate" and "a form of a printed circuit board" in the present application will be described. In addition, in the "form of copper-clad laminate", the "form of copper foil with carrier foil" in the present application will be described.

<Form of copper clad laminate>

1. The concept of layer construction of copper clad laminate

The copper clad laminate of the present application has, for example, a layer structure as shown in Fig. 1 . The copper-clad laminate of the present application is a laminate of a copper foil 11 having a carrier foil of the present application laminated on at least one side of the insulating layer structural material 5, and is shown in FIG. 1 (1-A). An example of the copper foil 11 with a carrier foil of the present application is laminated on both sides of the fifth embodiment. In Fig. 1 (1-B), the one side of the insulating layer structural material 5 is shown to be laminated. An example of a copper foil 11 of a sub-foil. Further, in the example shown in Fig. 1 (1-B), the other copper foil 2 is laminated on the other surface side of the insulating layer structural material 5. However, the copper clad laminate 1 shown in Fig. 1 is only an example of the copper clad laminate of the present application, and the invention of the present application is merely an explanation limited to the layer structure shown in Fig. 1.

1-1. Copper foil with carrier foil

First, the copper foil with a carrier foil of this application is described. The copper foil with carrier foil of the present application is characterized as follows: The layer structure of the "carrier foil 12 / release layer 13 / the entire copper layer 14" is provided, and both sides of the copper foil provided with the carrier foil have "having a composition of a copper composite compound and a maximum length of 500 nm. The roughened layer 4 of the fine concavo-convex structure formed by the convex portion of the needle-like or plate-like shape is provided on the roughened layer 4 on the surface of the carrier foil 12 as a laser light absorbing layer. The roughened layer 4 on the surface of the entire copper layer 14 is used as a bonding layer between the roughened layer and the insulating layer material. Further, the two sides of the copper foil having the carrier foil refer to the surface opposite to the side facing the peeling layer 13 of the carrier foil (the outer surface of the carrier foil below) and the opposite to the entire surface. The surface on the opposite side of the side of the peeling layer 13 of the copper layer 14 (the outer surface of the entire copper layer below). When the copper clad laminate is produced by using the copper foil with the carrier foil, the roughened layer on the entire copper layer side can be obtained to obtain a good density between the roughened layer and the insulating layer material. In combination, it is possible to obtain a copper clad laminate having excellent laser drilling performance by the roughened layer on the carrier foil side. Each of the constituent elements will be described below.

Carrier foil: The carrier foil of the copper foil provided with a carrier foil is not specifically limited. However, a roughened layer having a fine concavo-convex structure formed by a convex portion having a needle-like or plate-like shape composed of a copper composite compound and having a maximum length of 500 nm or less is provided in consideration of the surface of the carrier foil. In this case, the carrier foil is preferably a foil in which a copper component such as a copper foil or a copper-coated resin film is present on the surface.

Further, the thickness of the carrier foil is not particularly limited. However, in the present invention, when laser drilling is performed, a roughened layer provided on the outer surface of the carrier foil is used as the laser light absorbing layer. Therefore, considering the mine The thickness of the carrier foil is preferably in the range of 7 μm to 18 μm when the easiness of the drilling process, the shortening of the processing time, and the reduction of the material cost.

In this manner, the material and thickness of the carrier foil are not particularly limited. However, the laser drilling process is performed by irradiating laser light on the surface of the roughened layer to perform laser drilling. From a good point of view, it is preferable that the surface of the carrier foil has the following surface characteristics.

First, the outer surface of the carrier foil is preferably "the ratio between the surface area (three-dimensional area: Aμm ² ) and the area of the secondary element area when the secondary region of 57770 μm ² is measured by a laser method [ The value of the surface area ratio (B)" calculated by (A)/(57570)] is 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 when it is 1.5 or more, it becomes more favorable. On the other hand, when the value of the surface area ratio (B) exceeds 3.0, a variation occurs in the thickness of the carrier foil, and as a result, variation in the laser aperture is likely to occur. Therefore, the surface area ratio (B) of the outer surface of the carrier foil is preferably 3.0 or less.

Further, the surface roughness (Rzjis) of the outer surface of the carrier foil is preferably 2.0 μm or more. A roughened layer having the fine concavo-convex structure described above may be provided on the outer surface of the carrier foil having a surface having a surface roughness (Rzjis) of 2.0 μm or more, and the roughened layer may be used as a laser light absorbing layer. This makes the laser drilling process performance even better. It is desirable that the surface roughness of the outer surface of the carrier foil becomes thicker and the reflectance of the laser light on the outer surface of the carrier foil is lowered, and the laser drilling performance is improved. On the other hand, when the surface roughness (Rzjis) is 6.0 μm or more, the thickness of the carrier foil varies, and as a result, the laser aperture is likely to vary. Therefore, the carrier foil The surface roughness (Rzjis) of the outer surface is preferably 6.0 μm or less.

The release layer: the release layer of the copper foil with a carrier foil used in the laser drilling method of the present application is not particularly limited as long as the carrier foil can be peeled off later, as long as the release layer is satisfied. The desired properties may be any of an "organic release layer" formed using an organic component and an "inorganic release layer" formed using an inorganic component.

In the state in which the "organic release layer" is used as the release layer, it is preferable to use at least one or more compounds selected from the group consisting of nitrogen-containing organic compounds, sulfur-containing organic compounds, and carboxylic acids as the organic component. By. Here, the nitrogen-containing organic compound includes a nitrogen-containing organic compound having a substituent. Specifically, as the nitrogen-containing organic compound, it is preferred to use 1,2,3-benzotriazole, carboxybenzotriazole, N', N'-bis (benzo) which is a triazole compound having a substituent. Triazolylmethyl)urea, 1H-1,2,4-triazole, and 3-amino-1H-1,2,4-triazole, and the like. Next, as the sulfur-containing organic compound, mercaptobenzothiazole, thiocyanuric acid, 2-benzimidazolethione or the like is preferably used. Further, as the carboxylic acid system, a monocarboxylic acid is particularly preferably used, and among them, oleic acid, linoleic acid, linolenic acid or the like is preferably used. Since these organic components have good high-temperature heat resistance, a peeling layer having a thickness of 5 nm to 60 nm is easily formed on the surface of the carrier foil.

On the other hand, in the state in which the "inorganic release layer" is used as the release layer, Ni, Mo, Co, Cr, Fe, Ti, W, P may be used as the inorganic component or these elements may be used as the main component. At least one or more selected from the group consisting of alloys or compounds. In the state of these inorganic release layers, conventional methods such as an electrophoresis method, an electroless deposition method, and a physical vapor deposition method can be used. And formed.

In the present application, it is preferable to use any one of an organic peeling layer and an inorganic peeling layer. However, in the case of laminating between the peeling layer and the insulating layer structural material, it is also in a state of load heat energy, etc. From the standpoint of ensuring proper peel strength of the carrier foil, an organic release layer is preferred.

The entire copper layer is not particularly limited as long as the entire copper layer of the copper foil with a carrier foil used in the present application is detachably laminated on the copper foil of the carrier foil through the release layer. The method for producing the copper foil constituting the entire copper layer is not particularly limited, and copper can be produced by an electrolytic plating method, an electroless plating method, a vacuum deposition method, a sputtering vapor deposition method, a chemical vapor phase reaction method, or the like. The foil is manufactured by various methods of the conventional method. However, when considering the production cost and the like, it is preferable to manufacture the entire copper layer by electrolytic plating.

The thickness of the entire copper layer is not particularly limited, and may be a thickness such as a copper-clad laminate or a printed circuit board, which is required to form a copper layer. However, the copper foil provided with the carrier foil of the present application may have a roughened layer as a laser absorbing layer on the outer surface of the carrier foil, and is suitably used as a copper-clad laminate for laser drilling. The board is either a manufacturing material for a printed circuit board. When considering such a use form, the thickness of the entire copper layer is preferably from 0.1 μm to 9 μm. When the thickness of the entire copper layer is 9 μm or less, three layers of the "carrier foil/release layer/whole copper layer" can be simultaneously drilled while irradiating the laser beam on the outer surface of the carrier foil. On the other hand, when the thickness of the entire copper layer exceeds 9 μm, the thickness of the entire copper foil including the carrier foil is excessively thick, and the laser drilling performance is lowered, which is not preferable. In addition, on the other hand, when the thickness of the entire copper layer is less than 0.1 μm, it is not easy to obtain an overall copper having a uniform layer thickness. Layers, therefore, become less than ideal.

Therefore, the thickness of the entire copper layer is preferably thinner from the viewpoint of obtaining good laser drilling performance. Specifically, it is more preferably 5 μm or less, even more preferably 3 μm or less, and most preferably 2 μm or less. Further, it is preferable even if the thickness of the entire copper layer is made thinner and the entire copper layer is used to form a circuit. On the other hand, from the viewpoint of obtaining an overall copper layer having a more uniform layer thickness, the thickness of the entire copper layer is more preferably 0.5 μm or more, and even more preferably 1 μm or more.

The surface characteristics of the entire copper layer are not particularly limited. However, when the copper foil provided with the carrier foil is laminated on the insulating layer structural material to form a copper clad laminate, and the circuit is formed by using the copper clad laminate, the surface characteristics of the outer surface of the entire copper layer are considered. It is best to set the roughing layer before, as follows. The surface roughness (Rzjis) of the outer surface is preferably 2.0 μm or less, more preferably 1.5 μm or less, and even more preferably 1.0 μm or less. Further, the gloss (Gs 60°) of the outer surface of the entire copper layer is preferably 100 or more, more preferably 300 or more.

If the fine concavo-convex structure is formed on the outer surface of the entire copper layer having the surface characteristics described above, good adhesion between the fine concavo-convex structure and the insulating layer structure material can be obtained, and at the same time, high frequency characteristics are formed. Good circuit. That is to say, in order to suppress the transmission loss due to the skin effect in the high-frequency circuit, a conductor having a smooth surface is required to form a circuit. Here, in the state in which the so-called roughened layer of the present application is provided on the outer surface of the entire copper layer, there is a fear that the high-frequency signal is caused by the uneven structure provided on the outer surface. The transmission loss of the number. However, as will be described later, the fine concavo-convex structure is formed by a convex portion composed of a copper composite compound containing copper oxide and cuprous oxide, and therefore, a roughened layer composed of the fine concavo-convex structure There is no mobile high frequency signal. Therefore, the overall copper layer exhibits the same high frequency characteristics as the roughened copper layer without the roughening treatment. Further, the roughening treatment layer is excellent in adhesion to an insulating layer structural material using a low dielectric constant of a high-frequency substrate. Therefore, a copper foil having a carrier foil having a roughened layer having the fine uneven structure on the outer surface of the entire copper layer of the joint surface between the insulating layer structure and the insulating layer is suitable as a high-frequency circuit forming material. The circuit of the printed circuit board forms a material.

1-2. Roughening layer

In the present application, a fine concavo-convex structure formed by a convex portion having a needle-like or plate-like shape composed of a copper composite compound and having a maximum length of 500 nm or less is provided on both surfaces of a copper foil having a carrier foil. The roughening layer. Here, the roughened layer provided on the outer surface of the carrier foil provided with the copper foil of the carrier foil and the roughened layer provided on the outer surface of the entire copper layer constitute a fine layer of the roughened layer on each surface. The shape or size of the concavo-convex structure can be made common. In the following, the roughened layer is described in a state in which the roughened layer provided on the outer surface of the carrier foil and the roughened layer provided on the outer surface of the entire copper layer are not particularly distinguished. The matter is also common to any of the roughening layers.

A copper-clad laminate having a carrier foil having a roughened layer having the fine uneven structure on the outer surface of the carrier foil can be used as a laser light-absorbing layer by using a roughened layer. Carrier foil and integral copper Floor. Further, since the roughened layer having the fine concavo-convex structure is provided on the outer surface of the entire copper layer, good adhesion between the entire copper layer and the insulating layer structure material can be obtained. Further, the roughening treatment layer is different from the needle crystals formed by the conventional blackening treatment, and the other material system is not easily damaged by the convex portion forming the fine concavo-convex structure even if it contacts the surface. The phenomenon of so-called falling powder occurs. Therefore, the copper foil with a carrier foil of the present application has a roughened layer on both surfaces of the carrier foil and the outer surface of the entire copper layer, but no powder or the like occurs. Processing becomes easy.

Fig. 2 shows the surface morphology of the roughened layer when the so-called roughened layer of the present application is provided on the surface of a general electrolytic copper foil which can be used as a carrier foil. Here, in the state in which the electrolytic copper foil is used as the carrier foil, the entire copper layer can be arbitrarily provided on either the electrode surface side or the deposition surface side of the electrolytic copper foil. Therefore, when the electrolytic copper foil is used as the carrier foil, any one of the electrode surface side and the deposition surface side can be arbitrarily used as the outer surface, that is, the laser light irradiation surface. Therefore, in the state in which the laser light irradiation surface is provided on either side, each roughening layer is formed on the electrode surface side and the deposition surface side of the electrodeposited copper foil, and the roughened layer can be grasped. An observation image of a scanning electron microscope at the surface state.

As shown in Fig. 2, it is observed that the fine convex portions which are protruded into a needle shape or a plate shape are adjacent to each other and densely formed on the surface of each roughening treatment layer, and are formed on the surface of the electrolytic copper foil. The extremely fine concavo-convex structure is provided with these convex portions to cover the surface of the electrolytic copper foil along the surface shape of the electrolytic copper foil.

Here, the surface and the surface of the roughened layer on the side of the comparative electrolytic surface are analyzed. When the surface of the roughened layer is formed on the surface side, the shape of the micro surface of each surface is different. It is considered that the difference in the shape of the micro surface is caused by the difference between the electrode surface of the electrodeposited copper foil itself before the formation of the fine uneven structure and the shape of the micro surface of the deposition surface. As originally described, the electrode surface of the electrodeposited copper foil transfers the surface shape of the cathode and, therefore, becomes smooth. On the other hand, the other surface side (precipitation surface side) generally has a concavo-convex shape formed by electrodepositing copper. Referring to FIG. 2, it is known that the surface of the roughened layer maintains the micro surface shape before the roughening treatment of each surface of the electrolytic copper foil, and the electrode surface has a relatively smooth micro surface shape, and the deposition surface will be A miniature surface shape having irregularities is provided. This is considered to be a needle-like or plate-like convex portion having a maximum length of 500 nm or less, and is densely disposed on the surface of the electrolytic copper foil to cover the surface of the electrolytic copper foil along the surface shape of the electrolytic copper foil before the roughening treatment. Therefore, after the fine concavo-convex structure is formed, the micro surface shape of each surface of the electrolytic copper foil is also maintained.

Further, the fine concavo-convex structure is formed by a convex portion having a maximum length of 500 nm or less. When referring to FIG. 2, the arrangement pitch of the convex portions arranged on the surface of the copper foil (electrolytic copper foil) is shorter than each The length of the convex portion. Here, at the time of laser drilling, a carbon dioxide gas laser having a dominant wavelength of 9.4 μm and 10.6 μm is used. The surface of the roughening layer is arranged at a pitch of each convex portion, and is shorter than the emission wavelength of the carbon dioxide gas laser. Therefore, the surface of the roughened layer suppresses reflection of the laser light due to the carbon dioxide gas laser. Absorbs laser light with a high absorbance. Therefore, it can be suitably used as a laser light absorbing layer. Further, the maximum length of the convex portion forming the fine concavo-convex structure is 500 nm or less, and is relatively short when compared with the length of the convex portion formed by the conventional blackening treatment. Formed by the blackening process of the past Since the convex portion is tapered from the surface of the copper foil and protrudes in a long length, it is easily damaged by bending or the like in a state where the surface comes into contact with other objects, and so-called falling powder occurs during the treatment. On the other hand, in the so-called fine concavo-convex structure of the present application, there is no convex portion which is thickened and protrudes from the surface of the copper foil as in the conventional blackening treatment. Therefore, even if the operator's finger or the like comes into contact with the surface of the roughened layer during the treatment, the convex portion having the fine uneven structure is not bent to partially change the surface shape of the roughened layer or is The occurrence of the aforementioned falling powder such as fine powder of copper oxide scattered around can be easily handled.

Next, referring to Fig. 3, the "maximum length" of the convex portion will be described. Fig. 3 is an observation image of a scanning electron microscope showing a cross section of a copper foil having a carrier foil in the present application. However, in Fig. 3, a cross section on the side of the carrier foil of the copper foil provided with the carrier foil is shown. As shown in Fig. 3, in the cross section of the copper foil provided with the carrier foil, a portion which is a thin line-like convex portion is observed. In Fig. 3, it was confirmed that the surface of the copper foil was covered by the infinite number of convex portions which were densely bonded to each other, and each of the convex portions protruded 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 from the base end to the front end of each convex portion in the shape of the line (line portion) observed in the cross section of the copper foil. The maximum value of the time. Here, the roughening treatment layer using the outer surface of the carrier foil as the laser light absorbing layer is such that the longer the maximum length of the convex portion is, the more the laser light absorption rate is increased, and the laser drilling performance is improved. Further, the roughening treatment layer using the outer surface of the entire copper layer as the bonding layer between the entire copper layer and the insulating layer material is thicker, and the maximum length of the convex portion can be obtained by the fine fixing effect. Processing layer and Good adhesion between the edge layer construction materials. On the other hand, even if it is any one of the outer surface of the carrier foil and the outer surface of the entire copper layer, the maximum length of the convex portion is relatively easy to handle. When the surface of the roughened layer is in contact with other objects, the maximum length of the convex portion is relatively less susceptible to damage. Further, the shorter maximum length of the convex portion can maintain the surface shape of the copper foil before the roughening treatment, and the change in surface roughness before and after the roughening treatment can be suppressed. Next, a fine pitch circuit can be formed, which is equivalent to a good etching factor equivalent to the state in which the outer surface of the entire copper layer is a so-called roughened copper layer. Thus, good laser drilling performance can be maintained, and at the same time, a good adhesion with the insulating layer construction material and a good etching factor can be obtained together, and the viewpoint can be handled more easily. The maximum length of the convex portion is preferably 400 nm or less, more preferably 300 nm or less. On the other hand, when the maximum length of the convex portion is less than 100 nm, the laser drilling processability is lowered, and at the same time, the adhesion with the insulating layer construction material is also lowered. Therefore, the maximum length of the convex portion is preferably 100 nm or more.

Here, as shown in FIG. 3, the roughening treatment layer composed of the fine concavo-convex structure is formed on the surface layer portion of the copper foil, and is identified as a layer. The thickness of the roughened layer corresponds to the length (height) in the thickness direction in which the convex portion is protruded 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 necessarily the same, and the protruding direction of each convex portion is not flat with respect to the thickness direction of the copper foil. Further, there is a variation in the height of each convex portion. Therefore, variations occur in the thickness of the roughened layer. However, there is a certain correlation between the maximum length of the convex portion and the roughened layer. In the case where the average thickness of the roughened layer is 400 nm or less, the inventors of the present invention have a maximum length of 500 nm or less, as described above, from the copper foil. The convex portion having a surface on which the surface of the carrier foil or the entire copper layer starts to grow is not present, and therefore, it can be a roughened layer having a high scratch resistance. Therefore, it can be easily handled, and a good laser drilling process without deviation can be performed, and a good adhesion between the entire copper layer and the insulating layer construction material can be obtained.

In addition, when the surface of the roughened layer is observed in a plane at a magnification of 45° or more at a tilt angle of 45° or more using a scanning electron microscope, the convex portions adjacent to each other can be separated from other convex shapes. The length of the end portion before the observation is preferably 250 nm or less. Here, the length of the end portion that can be separated from the other convex portions and observed (hereinafter, abbreviated as "the length of the distal end portion") is referred to as the length shown below. For example, when observing the surface of the roughened layer by a scanning electron microscope, referring to FIG. 2, at the same time, as described above, the convex portion is protruded in a needle shape or a plate shape on the surface of the roughened layer. Since the convex portion is provided intensively on the surface of the copper layer, the interface between the convex portion of the convex portion and the copper foil, that is, the base portion of the convex portion, that is, the copper foil cannot be observed from the surface of the copper layer. Therefore, as described above, when the roughened layer of the copper layer is observed in a plane, the convex portions which are adjacent to each other while being dense and dense can be separated from the other convex portions and can be observed independently. There is a portion which becomes a convex portion, which is referred to as "the front end portion which can be separated from other convex portions and is observed", and the length of the front end portion refers to the front end of the convex portion (that is, the front end portion) Starting from the beginning) until the base can be separated from other convex parts for observation The length of the position on the end side.

In a state where the length of the front 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 compatibility between the laser drilling process performance and the insulating layer construction material, in any state, it is preferable that the maximum length of the convex portion is long and the most Preferably, the length of the front end portion of the convex portion is also relatively long. However, when the length of the end portion before the convex portion is lengthened, it is easily damaged when it comes into contact with other objects or the like. Therefore, from the viewpoint of the so-called well-maintained laser drilling processability and the adhesion with the insulating layer structural material while improving the scratch resistance and being easier to handle, the front end portion of the convex portion is The length system is preferably 200 nm or less, more preferably 100 nm or less. On the other hand, when the length of the front end portion of the convex portion is less than 30 nm, the laser drilling processability is lowered, and at the same time, the adhesion with the insulating layer construction material is also lowered. Therefore, the length of the front end portion of the convex portion is preferably 30 nm or more.

Further, the length of the front end portion of the convex portion is preferably 1/2 or less with respect to the maximum length of the convex portion. It is possible to separate from the other convex portions in a state where the ratio is 1/2 or less, and at the same time, the front end portion of the convex portion is protruded from the surface of the copper foil, and the fine concavo-convex structure is densely covered. The surface of the copper foil.

In addition, it is preferable that the specific surface area (hereinafter, simply referred to as "Kr adsorption specific surface area") which is measured by adsorbing ruthenium on the surface of the fine uneven structure in the roughened layer satisfies the so-called 0.035 m ² /g. The above conditions. Since the average height of the convex portion of the roughened layer is 200 nm when the Kr adsorption specific surface area is 0.035 m ² /g or more, good laser drilling performance and scratch resistance can be ensured stably. For the sake of it. Here, the upper limit of the Kr adsorption specific surface area is not determined, but the upper limit is about 0.3 m ² /g, more preferably 0.2 m ² /g. In addition, the Kr adsorption specific surface area at this time is the specific surface area made by Micromeritics. The pore distribution measuring device 3Flex was heated at 300 ° C for 2 hours for the sample as a pretreatment, and the liquid nitrogen temperature was used at the adsorption temperature, and the adsorbed gas was measured using krypton (Kr).

Next, the components constituting the fine concavo-convex structure will be described. As described above, the aforementioned convex portion is composed of a copper composite compound. In the present application, in view of the fact that the laser drilling process performance is good, in the roughening treatment layer as the laser light absorbing layer, the copper composite compound is preferably copper oxide, and can be made of copper oxide. It comes as a main component and contains cuprous oxide. In addition, in any state, 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, simply referred to as "XPS") is used. The proportion of the total area between the peak area of Cu(I) and the peak area of Cu(II) (the occupied area ratio below) is preferably the use of the roughened layer as the laser light absorbing layer. In the state, it is less than 50%. On the other hand, in the state in which the roughened layer is used as the bonding layer with the insulating layer structural material, it is preferable that the Cu(I) occupying area ratio is preferably 50% or more.

Here, it is explained that the structure of the aforementioned roughening layer is analyzed by XPS. The method of becoming an element. When the constituent elements of the fine concavo-convex structure are analyzed by XPS, the respective peaks of Cu(I) and Cu(II) can be separated and detected. However, in the state where the respective peaks of Cu(I) and Cu(II) are separated and detected, there is a state in which the Cu(0) peak is repeatedly observed in the shoulder portion of the large Cu(I) peak. In this way, in the state in which the Cu(0) peak is repeatedly observed, the shoulder portion is included and is considered to be a Cu(I) peak. In other words, in the present invention, the constituent elements of the copper composite compound which forms the fine concavo-convex structure using XPS are analyzed, and Cu(I) which is 932.4 eV corresponding to the bond energy of Cu2p3/2 is detected and appears in Each of the peaks obtained by photoelectrons of Cu(II) of 934.3 eV is separated by a waveform, and the area ratio of the Cu(I) peak is specified by the peak area of each component. However, as the XPS analyzer, Quantum 2000 (beam condition: 40 W, 200 μm diameter) manufactured by ULVAC-PHI Co., Ltd. can be used, and "MultiPack ver. 6.1A" is used as the analysis software. Semi-quantitative stenosis.

The Cu(I) crest system obtained as above is considered to be derived from monovalent copper constituting cuprous oxide (copper oxide: Cu ₂ O). Next, the Cu(II) peak system is considered to be derived from divalent copper constituting copper oxide (copper oxide: CuO). Further, the Cu(0) crest system is considered to be derived from zero-valent copper constituting metallic copper. Therefore, in the state where the occupied area ratio of the Cu(I) peak is less than 50%, the proportion of the cuprous oxide of the copper composite compound constituting the roughened layer is smaller than the ratio of the copper oxide. In the state in which the laser drilling performance is considered, the Cu(I) peak occupancy ratio is preferably as small as possible. That is to say, the best ideal is that the occupancy rate is less than 40%, less than 30%, less than 20%, etc., the smaller the value, the more the laser drilling performance is improved, the occupation rate is 0%. That is, the convex portion constituting the fine concavo-convex structure is composed only of copper oxide.

On the other hand, in the state where the roughened layer is provided on the outer surface of the entire copper layer, the roughened layer on the outer surface of the entire copper layer is different from the carrier foil which becomes the irradiated surface of the laser light. The surface roughening layer and the copper composite compound preferably contain copper oxide and cuprous oxide, and more preferably copper oxide as a main component. Specifically, in the roughened layer provided on the outer surface of the entire copper layer, the Cu(I) peak occupancy ratio is preferably 50% or more, more preferably 70% or more, and even more preferably 80%. The above is particularly preferably 90% or more.

In the state where the occupied area ratio of the Cu(I) peak is less than 50%, after the laser drilling process is performed on the copper layer, and when an electric circuit is formed by an etching method, in the etching liquid, It is easy to dissolve the structural components of the fine concavo-convex structure. Since the copper oxide is compared with cuprous oxide, the solubility in an acid such as an etching solution is high. Therefore, in a state where the occupied area ratio of the Cu(I) peak is less than 50%, it is likely that the adhesion between the copper layer and the insulating layer structural material is lowered afterwards, and thus it is not preferable.

The roughened layer on the outer surface of the entire copper layer is not particularly limited to the upper limit of the occupied area ratio of the Cu(I) peak, but is preferably 99% or less. The lower the occupied area ratio of the Cu(I) peak, the higher the tendency to improve the adhesion between the entire copper layer and the insulating layer structural material. Therefore, in order to obtain good adhesion between the two, the area ratio of the Cu(I) peak is preferably 98% or less, more preferably 95% or less. Further, the occupied area ratio of the Cu(I) peak is calculated by a calculation formula of Cu(I) / {Cu(I) + Cu(II)} × 100 (%).

The fine concavo-convex structure described above can be caused by, for example, the following wet type on both sides of the copper foil having the carrier foil (that is, the outer surface of the carrier foil and the outer surface of the entire copper layer). The roughening treatment forms a fine uneven structure. First, oxidation treatment is performed on both surfaces of a copper foil provided with a carrier foil by a wet method, and copper oxide (copper oxide: CuO) is mainly formed on both surfaces of a copper foil having a carrier foil. a copper composite compound of the composition. In this case, a "fine concavo-convex structure formed by a convex portion of a needle shape or a plate shape" composed of a copper composite compound containing copper oxide as a main component is formed on both surfaces of a copper foil having a carrier foil. . Then, the reduction treatment can be carried out by the need of blending, and a part of the copper oxide is reduced on both sides or one side of the copper foil with the carrier foil to form cuprous oxide (cuprous oxide: Cu ₂ O). On both sides or a single surface of a copper foil having a carrier foil, a "fine concavo-convex structure formed by a convex portion of a needle shape or a plate shape" composed of a copper composite compound containing copper oxide and cuprous oxide is formed. Here, the "fine concavo-convex structure" itself in the present application is formed at the stage of oxidation treatment. Therefore, in a state in which a fine concavo-convex structure having copper oxide as a main component or a fine concavo-convex structure composed of copper oxide is formed, the refining treatment can be completed without performing a reduction treatment after the oxidation treatment. On the other hand, in the state in which the fine concavo-convex structure containing cuprous oxide is contained in a predetermined ratio, the reduction treatment can be performed after the oxidation treatment. Even in the case of performing the reduction treatment, a part of the copper oxide is reduced to cuprous oxide in a state where the shape of the fine concavo-convex structure is maintained almost at the stage of the oxidation treatment. As a result, a "fine concavo-convex structure" composed of a copper composite compound containing copper oxide and cuprous oxide can be formed. In this way, by performing an oxidation treatment on the both surfaces of the copper foil provided with the carrier foil by a wet method or the like, and performing a necessary degree of reduction treatment as needed, the so-called "fine bumps" in the present application can be formed. structure". 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 by the wet method described above is carried out, it is preferred to use an alkali solution such as a sodium hydroxide solution. By using an alkali solution, both sides of the copper foil provided with the carrier foil can be oxidized, and a copper composite compound containing copper oxide as a main component in a needle shape or a plate shape can be formed on both surfaces of the copper foil provided with the carrier foil. The convex part of the composition. Here, in the state where the oxidation treatment is performed on both surfaces of the copper foil provided with the carrier foil by the alkali solution, the convex portion is grown to have a maximum length exceeding 500 nm, which is not easy. The so-called fine concavo-convex structure formed in the present application. Then, in order to form the above-described fine concavo-convex structure, it is preferable to use an alkali solution containing an oxidation inhibitor which can suppress oxidation of both surfaces of the copper foil provided with the carrier foil.

Examples of such an oxidation inhibitor include an amine-based decane coupling agent. If an alkali solution containing an amine-based decane coupling agent is used to perform oxidation treatment on both sides of a copper foil having a carrier foil, the amine-based decane coupling agent in the alkali solution can be adsorbed on the carrier-containing foil. Both sides of the copper foil suppress oxidation due to the alkali solution. As a result, the growth of the needle crystals of the copper oxide can be suppressed, and an extremely fine uneven structure can be formed on both surfaces of the copper foil provided with the carrier foil.

As the aforementioned amino decane coupling agent, N-2-(aminoethyl)-3-aminopropylmethyldimethoxydecane, N-2-(aminoethyl)-3-amine can be specifically used. Propyltrimethoxydecane, 3-aminopropyltrimethoxydecane, 3-aminopropyltriethoxydecane, 3-triethoxymethylidene-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethyl Oxydecane, etc. These systems are all dissolved in an alkaline solution, and are stably held in an alkaline solution, and at the same time, exhibit an effect of suppressing oxidation of both surfaces of the copper foil having the carrier foil described above.

As described above, the fine concavo-convex structure formed by performing the oxidation treatment on both surfaces of the copper foil containing the carrier foil by the alkali solution containing the amine-based decane coupling agent is almost always performed after the reduction treatment. Maintain its shape. As a result, a roughening treatment layer having a needle-like or plate-like convex portion having a maximum length of 500 nm or less composed of copper oxide and cuprous oxide and composed of these copper composite compounds can be formed. A fine concavo-convex structure formed. Further, in the reduction treatment, Cu (I) obtained by qualitative analysis using a constituent element of a copper composite compound having a fine uneven structure by adjusting a reducing agent concentration, a solution pH, a solution temperature, or the like using XPS can be used. The peak area is appropriately adjusted with respect to the occupied area ratio of the total area between the peak area of Cu(I) and the peak area of Cu(II). Further, for example, it is immersed in an alkali solution by a copper foil provided with a carrier foil, and is formed on both surfaces of the copper foil having the carrier foil, that is, the outer surface of the carrier foil and the outer surface of the entire copper layer. In the fine concavo-convex structure in which copper oxide is used as a main component, and then the reduction treatment is performed only on the roughened layer on the outer surface of the entire copper layer, the laser light irradiation surface system can make the Cu(I) peak occupancy ratio become The joint surface between 0% and the insulating layer structural material may be a copper foil having a carrier foil having a Cu(I) peak occupancy ratio of 50% or more. When the constituent elements of the fine concavo-convex structure formed by the above method were analyzed by XPS, the presence of "-COOH" was detected.

As described above, the oxidation treatment and the reduction treatment can be carried out by the wet method. Therefore, the copper foil having the carrier foil can be immersed in the treatment solution, and the copper having the carrier foil can be used. The above-mentioned fine concavo-convex structure is formed on both sides of the foil. Therefore, when the fine concavo-convex structure is formed on both surfaces of the copper foil provided with the carrier foil by the wet method, the laser drilling processability on the side of the laser beam irradiation surface can be improved, and at the same time, it is possible to borrow Due to the nano-fixing effect caused by the fine concavo-convex structure, the adhesion between the insulating layer structural material and the entire copper layer is improved. In addition, as described above, the fine uneven structure has a high scratch resistance. Therefore, even if the fine uneven structure is formed on both surfaces of the copper foil having the carrier foil, it is easy to handle, and powder falling or the like can be prevented.

1-3. Treatment of decane coupling agent

The ruthenium coupling agent treatment layer can be provided on the surface of the roughened layer on the outer surface of the entire copper layer by the copper foil provided with the carrier foil, thereby improving the moisture absorption deterioration resistance when processed into a printed circuit board. Any of the decane coupling agent treatment layers disposed on the roughening treatment surface may be any of an olefin functional decane, an epoxy functional decane, a vinyl functional decane, a propylene functional decane, an amine functional decane, and a thiol functional decane. One is to form a decane coupling agent treatment layer as a decane coupling agent. These decane coupling agents are represented by the general formula R-Si(OR')n (here, R: an organic functional group represented by an amine group or a vinyl group, OR': a methoxy group or an ethoxy group, etc. The hydrolyzed group represented by n, 2 or 3.).

As the so-called decane coupling agent used herein, the same coupling agent as that of the fiberglass cloth used for the adhesive sheet for printed circuit boards can be used. Centered vinyl trimethoxy decane, vinyl phenyl trimethoxy decane, γ-methyl propylene propyl propyl trimethoxy decane, γ-glycidoxypropyl trimethoxy decane, 4-ring Oxypropyl propyl trimethoxy decane, γ-aminopropyl triethoxy decane, N-β (aminoethyl) γ-aminopropyl trimethoxy decane, N-3-(4-(3) -Aminopropoxy)butoxy)propyl-3-aminopropyltrimethoxydecane, imidazolium, triazine decane, 3-propene oxide propyl methoxy decane, γ-mercaptopropyltrimethoxy Base decane and the like.

The decane coupling agent exemplified herein has no adverse effect on the characteristics after it becomes a printed circuit board. Whether or not any of the types of the decane coupling agent can be used can be appropriately selected in accordance with the use of the copper clad laminate or the like.

Preferably, the decane coupling agent is a decane coupling agent treatment liquid which is a temperature at a room temperature level, and the decane coupling agent treatment liquid contains water as a main solvent and the decane coupling agent component is 0.5 g/L to 10 g. /L concentration range. In the state where the concentration of the decane coupling agent in the decane coupling agent treatment liquid is less than 0.5 g/L, the adsorption rate of the decane coupling agent becomes slow, which is not compatible with the calculation of a general commercial substrate, and the adsorption also becomes uneven. On the other hand, even if the concentration of the decane coupling agent exceeds 10 g/L, the speed of adsorption is not particularly accelerated, and the performance quality such as moisture absorption deterioration resistance is not particularly improved, which is uneconomical, and therefore, it is not preferable.

The decane coupling agent treatment liquid and the decane coupling agent may be a method of adsorbing the surface of the roughened layer by a dipping method, a shower ring method, a spray method, or the like, and are not particularly limited. That is to say, it can be designed to match the surface of the roughened layer and the decane coupling agent in the most uniform manner. Liquid to carry out the adsorption method.

After adsorbing the decane coupling agent on the surface of the roughened layer, sufficient drying is performed to promote a condensation reaction between the -OH group at the surface of the roughened layer and the adsorbed decane coupling agent, completely evaporating due to The water produced as a result of the condensation. There is no particular limitation on the drying method at this time. For example, even if an electric heater is used, there is no particular limitation on the method of blowing the warm air, and a drying method and drying conditions suitable for the production line can be employed. However, the above-described decane coupling agent treatment is performed for the roughening treatment layer on the outer surface of the entire copper layer in order to improve the adhesion with the insulating layer structural material, and does not need to be applied to the carrier foil. The roughened layer of the outer surface.

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

As described above, the acicular or plate-like convex portions having a maximum length of 500 nm or less constituting the fine concavo-convex structure are arranged by being shorter than the wavelength of the carbon dioxide gas laser and shorter than the wavelength range of the visible light. . The light incident on the surface of the roughened layer is in the fine concavo-convex structure, and is repeatedly subjected to chaotic reflection, and as a result, attenuation occurs. That is, the surface of the roughened layer functions as a light absorbing surface, and the surface of the roughened layer is darkened to be black, brown or the like as compared with the case before the roughening treatment. That is, the copper-clad laminate of the present application is also characterized by the color tone of the surface of the roughened layer on the outer surface of the carrier foil as the laser light absorbing layer, and has a characteristic L ^* a ^* b ^* color The brightness L ^* is 30 or less, preferably 25 or less. When the value of the luminance L ^* exceeds 30 and becomes a bright color tone, the maximum length of the convex portion constituting the fine concavo-convex structure exceeds 500 nm, which is undesirable. Further, in a state where the value of the luminance 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 disposed on the outer surface of the carrier foil. In other words, it is considered that the state of the roughening treatment is insufficient in the state where the value of the luminance L ^* exceeds 30, or the unevenness occurs in the state of the roughening treatment, and the entire copper layer is not transmitted through the carrier foil. It is suitable for the state of laser drilling and is not ideal. Next, when the luminance L ^{* is} 25 or less, the surface of the roughened layer is more suitable for laser drilling. In addition, the measurement of the luminance L ^{* was carried out} by using a spectrophotometer SE2000 manufactured by Nippon Denshoku Industries Co., Ltd., and the brightness was corrected. Therefore, the measurement device was measured in accordance with JIS Z8722:2000 using an attached white plate. Next, the same portion was measured three times, and the average value of the measured data of the luminance L ^* of three times was used as the value of the so-called luminance L ^{* in} the present application. Further, even in the case of the roughened layer provided on the outer surface of the entire copper layer, the value of the luminance L ^* is the same even in the case of obtaining a good adhesion with the insulating layer structural material. The roughened layer of the outer surface of the carrier foil. However, even in the state in which the above-described decane coupling agent treatment is performed on the roughened layer provided on the outer surface of the entire copper layer, the value of the luminance L ^{* on} the surface of the roughened layer before and after the film is No change occurs.

2. The basic concept of laser drilling method

Next, referring to Fig. 4, a description will be given of a method of performing laser drilling processing using the above-described copper clad laminate. Here, a state in which the copper-clad laminate 1 having the same layer structure as that of the embodiment shown in Fig. 1 (1-A) is subjected to laser drilling is described as an example. The copper clad laminate 1 of the present application is on at least one side of the insulating layer construction material 5, and the laminated product The bonding layer side of the entire copper layer 14 of the copper foil 11 containing the carrier foil of the application. Therefore, as shown in FIG. 4(A), the surface on which the laser light is irradiated (the laser irradiation surface) is the outer surface of the carrier foil 12 having the copper foil 11 of the carrier foil. The outer surface of the carrier foil 12 is provided with a roughened layer having the fine uneven structure. Therefore, if the laser beam is irradiated from the outer surface side of the carrier foil 12, the carrier foil 12 and the entire carrier foil can be simultaneously provided. The copper layer 14 is used for laser drilling. Then, by peeling off the carrier foil 12, starting from the surface of the entire copper layer, the splash and the carrier foil existing around the opening of the via hole formed by the laser drilling process can be removed together. The via hole 10 shown in FIG. 4(B) in which the periphery of the opening portion is flat can be formed.

Here, in the present application, consideration is given to the reason why the above-described roughened layer is provided on the outer surface of the carrier foil which is the irradiation surface of the laser light to improve the laser drilling performance. First, the roughened layer is formed by the outer surface of the carrier foil, and as described above, the surface of the roughened layer becomes a black or brownish matte surface, and the reflection of the laser light is suppressed. As a result, the thermal energy of the laser light can be efficiently supplied to the laser light irradiation portion. On the other hand, in the state in which the laser light irradiation surface of the copper clad laminate is a copper layer (so-called carrier foil or integral copper layer, the same applies hereinafter), as long as the surface is not roughened or blackened. In the case of processing or the like, the surface of the copper layer is a mirror surface and reflects the laser light. Therefore, the thermal energy of the laser light cannot be efficiently supplied to the laser light irradiation portion.

Further, the boiling point of copper relative to copper is 2562 ° C, and 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 relatively low when compared with copper. Therefore, when the laser light is irradiated onto the surface of the roughened layer, the laser irradiation portion on the surface of the roughened layer rapidly reaches the boiling point in a state where the copper layer itself is irradiated with the laser light. On the other hand, the thermal conductivity of copper is at 700 ° C, which is 354 W. m ^-1 . K ^-1 , relatively, the thermal conductivity of copper oxide and cuprous oxide are both at 700 ° C, becoming 20 W. m ^-1 . K ^-1 or less. That is, the thermal conductivity of copper oxide and cuprous oxide becomes extremely small with respect to 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 relatively low to 1083 ° C. Therefore, when the copper layer itself is in the state of being irradiated with the laser light, the speed at which the thermal energy is transmitted to the outside of the laser irradiation portion is slow in the state where the surface of the roughened layer is irradiated with the laser light. As a result, the heat energy can be concentrated in the depth direction, and the temperature of the carrier foil and the entire copper layer can be easily made higher than the melting point. Therefore, it can be provided on the laser beam irradiation surface by the fine concavo-convex structure composed of the copper composite compound described above, and the laser beam can be efficiently performed when the copper layer itself is in the state of the laser beam irradiation surface. Drilling processing.

<Form of printed circuit board>

The printed circuit board of the present application is characterized in that it has a copper layer formed by using the entire copper layer of the copper foil with a carrier foil of the present application, and can be manufactured by using the copper clad laminate of the present application. Further, in the printed circuit board of the present application, it is preferable that the copper layer is provided with via holes formed by laser drilling. For example, it can be a multilayer printed circuit board manufactured by the build-up process shown in FIGS. 5 to 7.

In the following, the form and manufacturing method of the printed circuit board of the present application will be described with reference to FIGS. 5 to 7. However, this application The layer structure or the manufacturing method of the printed circuit board is not limited to the form described below, and may be included if the copper layer is formed using the entire copper layer of the copper foil with the carrier foil of the present application. Any form.

In Figs. 5 to 7, an example of a manufacturing process of a multilayer printed circuit board by a so-called build-up method is shown. For example, as shown in FIG. 5(A), on both sides of the inner substrate 9 having the inner layer circuit 8, the adhesive sheet is passed through. A copper foil 11 having a carrier foil having a layer structure of "a carrier foil 12 / a release layer 13 / an entire copper layer 14" is laminated on the insulating layer structural material 5 such as a resin film, and the first increase in the carrier foil is obtained. The layered body 40 is laminated. At this time, the copper foil 11 provided with the carrier foil may be laminated only on one side of the insulating layer structural material 5. In the example shown in FIG. 5(A), the inner layer substrate 9 is provided on both surfaces thereof, and the inner layer circuit 8 is provided to form field via holes (via holes) 10 for interlayer connection. However, the inner layer substrate 9 is not limited to the one shown in FIG. 5(A), and the layer structure or the like may be any.

Next, as shown in FIG. 6(B), the surface of the roughened layer 4 of the carrier foil 12 of the first buildup layered body 40 having the carrier foil is irradiated with laser light to perform laser drilling. At the time of completion of the laser drilling process, the carrier foil 12 is peeled off by the peeling layer 13, and all the splashes existing around the opening portion of the hole formed by the laser drilling process are removed. The surface of the entire copper layer 14 which is clean without splashing is exposed, and the laminated body 41 having the first buildup shown in Fig. 6(C) is in a state. Further, in the state in which the first buildup layered body 40 having the carrier foil shown in Fig. 6(B) is present, the carrier foil 12 having the roughened layer 4 having the fine uneven structure is provided on both surfaces thereof. Therefore, it is possible to easily perform the thunder from the both sides of the first buildup layered body 40 having the carrier foil. Shot drilling. Next, a desmear process for removing the resin residue generated by the laser drilling process is performed, and the via hole 10 is formed by plating and filling in the via hole, and a plating layer is formed on the surface of the entire copper layer. twenty four. Then, the first build-up wiring layer 31 can be formed by etching, and the laminate 42 having the first build-up wiring layer shown in FIG. 7(D) can be formed.

In addition, the two sides of the laminate 42 having the first build-up wiring layer shown in Fig. 7 (D) are passed through the adhesive sheet. When the copper foil 11 having the carrier foil is laminated on the insulating layer structural material 5 such as a resin film, the second buildup layer provided with the carrier foil having the second build-up wiring layer 32 shown in FIG. 7(E) is provided. Laminate 43. In this manner, the same operation as in FIG. 6(B), FIG. 6(C), and FIG. 7(D) can be repeatedly performed by the need of the cooperation to form the n-th circuit pattern layer (n≧3). : integer) layered layer body. In this case, it is also preferable to use a copper foil having a carrier foil provided with a resin layer for forming a resin layer on the outer surface of the entire copper layer 14 instead of the insulating layer structural material 5 and the foregoing. The use of a copper foil 11 having a carrier foil of a layer structure of "carrier foil 12 / release layer 13 / overall copper layer 14".

Then, laser drilling processing is performed to complete the multi-layer laminated board of the final layer, and the desmear treatment for removing the resin residue generated by the laser drilling process is performed, and plating is performed in the via hole. The surface is filled to form a field via, and a plating layer is formed on the surface of the entire copper layer. Then, the copper layer of the outer layer is etched or the like to form an outer layer circuit to form a multilayer printed circuit board.

The printed circuit board of the present application can be manufactured by using the copper foil 11 with carrier foil of the present application, and after laser drilling, The peeling layer 13 peels off the carrier foil 12, and completely removes the spatter existing around the opening of the via hole formed by the laser drilling process. Therefore, the surface of the entire copper layer around the opening of the via hole can be made clean, by electroplating. The filling or plating of the plating in the via hole is performed by etching or the like. Further, the adhesion between the roughened layer and the insulating layer material 5 constituting the interlayer insulating layer can be obtained by roughening the layer 4 on the outer surface of the entire copper layer 14.

Hereinafter, the technical advantages of producing a copper clad laminate and a printed circuit board using the copper foil of the carrier foil of the present application will be described by way of examples and comparative examples.

[Example 1]

A copper foil with a carrier foil of the present application was produced as follows. First, an unprocessed copper foil with a carrier foil having a layer structure of "carrier foil/release layer/whole copper layer" was prepared. As the untreated copper foil with a carrier foil, the surface roughness (Rzjis) of the outer surface of the carrier foil was 5.3 μm, the gloss [Gs (60°)] was 2.1, and the thickness of the carrier foil was The composition is 12 μm, the thickness of the entire copper layer is 1.5 μm, and the release layer contains an organic release layer of 1,2,3-benzotriazole. The copper foil with a carrier foil of the present application is obtained by applying the surface to the outer surface of the unprocessed copper foil with a carrier foil and the outer surface of the entire copper layer by the following procedure. The treatment has a roughening treatment layer on both sides. Further, the methods of measuring the surface roughness, the surface area ratio, and the gloss are as follows.

[Measurement of roughness]

Using a stylus surface roughness meter made by Otaru Research Institute SE3500 was measured for surface roughness in accordance with JIS B 0601-2001.

[Measurement of surface area ratio]

Using a laser microscope VK-X100 manufactured by KEYENCE Co., Ltd., the surface area ratio (B) was determined according to the above calculation formula based on the surface area A when a secondary region of 57570 μm ² was measured by a laser method.

[Measurement of gloss]

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

After the preliminary treatment is performed on the copper foil provided with the carrier foil, the roughening treatment is performed. In the following, the description will be made in order.

Preparation treatment: The copper foil containing the carrier foil was immersed in an aqueous sodium hydroxide solution, and subjected to alkali degreasing and water washing. Next, the copper foil containing the carrier foil degreased with the alkali 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: An oxidation treatment is performed on the copper foil with a carrier foil subjected to the aforementioned preliminary treatment. In the oxidation treatment, the copper foil 11 containing the carrier foil is immersed in a predetermined oxidation treatment time (1 minute, 2 minutes, 4 minutes, 10 minutes) at a liquid temperature of 70 ° C, pH = 12, and chlorine. A sodium hydroxide solution having an acid concentration of 150 g/L and a N-2-(aminoethyl)-3-aminopropyltrimethoxydecane concentration of 10 g/L is formed to contain oxidation on both surfaces of the copper foil 11 having a carrier foil. Copper copper compound.

Next, the copper foil containing the carrier foil which has been subjected to the oxidation treatment is immersed in a dimethylamine adjusted to pH = 12 using sodium carbonate and sodium hydroxide. The solution was subjected to a reduction treatment for 1 minute in an aqueous solution (room temperature) having a borane concentration of 20 g/L, and washed with water and dried. By these processes, four kinds of copper foils having a carrier foil having the fine concavo-convex structure of the present application are provided on the outer surface of the carrier foil and the outer surface of the entire copper layer.

These four types of copper foils containing carrier foils were used as samples, and the surface of the roughened layer of the carrier foil of each sample was subjected to qualitative analysis using XPS. As a result, in the entire sample, the existence of "copper oxide" and "copper oxide" was clearly confirmed. The occupied area ratio of the total area of the peak of Cu(I) of each sample with respect to the peak area of Cu(I) and the peak area of Cu(II) is shown in Table 1, respectively. Further, from the results of the qualitative analysis, it was confirmed that "-COO group" exists in all the samples. In Table 1, the occupied area ratio of the peak of Cu(I) and the Kr adsorption specific surface area and the luminance L ^* of the surface of the roughened layer on the outer surface of the carrier foil of each sample were collectively arranged and displayed. In addition, in Table 1, "Kr adsorption specific surface area" is simply shown as "specific surface area".

Further, the above-mentioned four kinds of samples were respectively brought into contact with both surfaces of the insulating layer structural material, and laminated using a vacuum press at a punching pressure of 3.9 MPa, a temperature of 220 ° C, and a pressing time of 90 minutes. However, as the insulating layer structural material, a prepreg GFPL-830NS manufactured by Mitsubishi Gas Chemical Co., Ltd. was used. Thereby, a copper clad laminate having a copper foil having a carrier foil on both surfaces of the insulating layer structural material was obtained.

In addition, after the above-mentioned four kinds of samples are laminated on one surface of the insulating layer structural material by the above-described method, the carrier foil is peeled off, and the copper plating layer is adhered and formed on the exposed entire copper layer, and is produced. A copper clad laminate of a copper layer having a thickness of 18 μm. Next, using this sample, it is produced by an etching method. A test substrate for a linear circuit for measuring the peel strength of 0.4 mm width. Next, the peel strength of each test substrate was measured in accordance with JIS C6481 (1996).

[Example 2]

In Example 2, except that the untreated copper foil with a carrier foil similar to that of Example 1 was used, the copper foil with the carrier foil for the preliminary treatment was subjected to oxidation treatment on both sides (oxidation treatment time 2 After the minute, on the outer surface of the carrier foil, no reduction treatment is applied, only on the outer surface of the whole copper layer, sprayed. The spray was the same as that of the reduction treatment solution of Example 1, except that the reduction treatment was carried out, and the same procedure as in Example 1 was carried out, and the fine concavo-convex structure of the present application was obtained to be provided on the outer surface of the carrier foil and the outer surface of the entire copper layer. Copper foil with carrier foil. Next, in the same manner as in Example 1, the occupied area ratio of the total area between the peak of Cu(I) and the peak area of Cu(I) of each surface and the peak area of Cu(II), and the carrier foil were determined. The Kr adsorption specific surface area and brightness L ^{* of the} surface of the roughened layer are roughened. The results are shown in Table 1. Further, even in the case of the copper foil provided with the carrier foil of Example 2, the existence of the "-COO group" was clearly confirmed. Further, a copper-clad laminate was obtained in the same manner as in Example 1, and a test substrate for measuring the peel strength was prepared, and the peel strength was measured.

[Comparative example]

[Comparative Example 1]

In Comparative Example 1, the untreated copper foil with a carrier foil similar to that of Example 1 was used, and the outer surface of the carrier foil was not subjected to roughening treatment, and only the outer surface of the entire copper layer was subjected to conventional practice. The roughening treatment (the roughening treatment of the fine copper particles formed by the copper sulfate-based copper electrolytic solution). Using the copper foil provided with the carrier foil of Comparative Example 1 obtained in this manner, copper was obtained in the same manner as in Example 1. Laminated board.

[Comparative Example 2]

In Comparative Example 2, the copper foil with the carrier foil similar to that of Example 1 was used, and the preliminary treatment similar to that of Example 1 was carried out, blackening treatment was performed on both sides, and reduction treatment was carried out in the carrier. On the outer surface of the foil and the outer surface of the entire copper layer, a copper foil with a carrier foil having a conventional reduced blackening layer was obtained. In the following, the procedures of the blackening process and the restoration process will be described.

Blackening treatment: A general blackening treatment is performed on the copper foil with a carrier foil which is subjected to the aforementioned preliminary treatment. In the oxidation treatment, an aqueous solution containing 10 vol% of "PRO BOND 80A OXIDE SOLUTION" which is an oxidation treatment liquid manufactured by Rohm and Haas Electronic Materials Co., Ltd. and 20 vol% of "PRO BOND 80B OXIDE SOLUTION" at a liquid temperature of 85 ° C is used. After immersion for 5 minutes, it became blackened.

Reduction treatment: A reduction treatment is performed on a copper foil having a carrier foil subjected to a blackening treatment. In the reduction treatment, an aqueous solution containing 6.7 vol% of "CIRCUPOS IT PB OXIDE CONVERTER 60C" which is a reducing treatment liquid manufactured by Rohm and Haas Electronic Materials Co., Ltd. and 1.5 vol% of "CUPOS IT Z" at a liquid temperature of 35 ° C , immersed for 5 minutes, washed with water and dried. By these processes, a copper foil with a carrier foil having a general reduced blackening layer is obtained. Next, in the same manner as in Example 1, the occupied area ratio of the total area between the peak of Cu(I) and the peak area of Cu(I) of each surface and the peak area of Cu(II), and the carrier foil were determined. The Kr adsorption specific surface area and the luminance L ^{* of the} surface of the roughened layer are roughened. The results are shown in Table 1.

In addition, the copper with the carrier foil obtained as above is used. In the same manner as in Example 1, a copper-clad laminate was obtained, and a test substrate for measuring the peel strength was prepared, and the peel strength was measured.

[Evaluation results]

In Table 1 below, the specific surface area and the luminance L ^* of the fine concavo-convex structure formed on the surface of the carrier foil of the copper foil having the carrier foil obtained in Example 1, Example 2, and Comparative Example 2 are shown. The measurement result of the peeling strength at the time of the roughening of the outer surface of the copper layer to laminate the insulating layer structural material. Further, Fig. 8 shows an observation image of a scanning electron microscope using a linear circuit having a circuit width of 8 μm and an inter-circuit slit width of 8 μm, which was produced using the copper foil of the carrier foil obtained in Example 1.

As can be understood from Table 1, even if the oxidation treatment time fluctuated between 1 minute and 10 minutes, the fine unevenness formed on the outer surface of the carrier foil of the copper foil with the carrier foil of the example was convex. The maximum length of the shape is 500 nm or less, and there is no difference from the qualitative analysis of the fine unevenness. Further, even with respect to the value of the luminance L ^* of the surface of the roughened layer, the value of the deviation of 18 to 25 is shown to be very small. On the other hand, the Kr adsorption specific surface area ratio is increased in the oxidation treatment time to make the value larger. Then, it is found that when the peeling strength is measured by laminating the insulating layer structure material on the bonding layer side of the outer surface of the entire copper layer of the copper foil having the carrier foil, the shortest oxidation treatment time is practical. Further, a sufficient peel strength was obtained, and a peel strength in which the ratio of the Kr adsorption specific surface area was obtained was obtained. From this, it can be understood that the oxidation treatment time employed in the examples becomes appropriate.

Comparison between Example and Comparative Example 1: Here, a review was made regarding the performance of laser drilling. The carbon dioxide gas laser system was a laser light source, and the carrier foil was used for the copper-clad laminate using the copper foil with a carrier foil obtained in the examples and the copper-clad laminate obtained in Comparative Example 1. The side begins to illuminate the laser light. At this time, a laser having a mask diameter of 2.0 mm, a pulse width of 14 μsec., a pulse energy of 19.3 mJ, a bias of 0.8, and a laser light path of 153 μm was used, and the copper was prepared in the copper-clad laminate having the carrier foil. The layer was formed to form a hole having a processing diameter of 60 μm, and a via hole formation test was performed for 100 times of each copper-clad laminate. Then, after the laser irradiation, the carrier foil was removed, and it was judged that the hole formed in the entire copper layer was 60 μm or more, and the processing was performed satisfactorily. The results are shown in Table 2.

As is apparent from Table 2, it can be judged that in the state of the embodiment, it is possible to perform a good laser drilling process on all the copper-clad laminates. On the other hand, in the state of Comparative Example 1, it was not easy to simultaneously drill the carrier foil and the entire copper layer in the same laser processing conditions as applied to the examples. Further, in the so-called aperture ratio of Table 2, a via hole formation test was performed for 100 shots, and the ratio of the number of shots of the laser drilled hole was completed. Next, the opening diameter distribution is a distribution width when the opening diameter of the via hole obtained by the through hole forming test of 100 shots is measured.

Comparison between Example and Comparative Example 2: When the laser drilling performance was evaluated in the same manner as in Comparative Example 2, the laser drilling performance of the copper-clad laminate of Comparative Example 2 was equivalent. In the examples. However, in the copper clad laminate of Comparative Example 2, the surface of the reduced blackening layer on the outer surface of the carrier foil is liable to cause scratches. The tendency of friction and the like occurs. A bruise occurred. The surface of the reduced blackening layer such as friction is lustrous. In the state where the surface of the reduced blackening layer is glossy, the laser drilling performance is remarkably lowered, and the laser drilling process cannot be performed on the copper clad laminate. On the other hand, in the copper foil with carrier foil used in the laser drilling process of the present application, no scratches occur. Friction, etc., does not cause a reduction in the performance of laser drilling.

Further, the copper foil with a carrier foil for laser drilling obtained in Example 1 and the copper foil with a carrier foil used in Comparative Example 1 and Comparative Example 2 were used, and an attempt was made by MSAP (Modified). Semi Additive Process: A linear circuit with a circuit height of 12 μm, a circuit width of 8 μm, and a gap width between circuits of 8 μm. As a result, in the state of using the copper-clad laminate having the copper foil of the carrier foil obtained in the examples, The observation image of the scanning electron microscope shown in Fig. 8 (Fig. 8(a) is a stereoscopic observation image, and Fig. 8(b) is a cross-sectional observation image), and it was found that the above-described linear circuit was obtained. On the other hand, in the state of the copper-clad laminate obtained in Comparative Example 1 and Comparative Example 2, the above-described linear circuit could not be obtained when the etching time was lengthened in comparison with the examples. It takes time until the fine copper particles are completely removed or the blackening treatment layer is removed, during which etching of the circuit is performed, the height of the circuit is lowered, and the width of the circuit is also reduced. Therefore, it can be understood that a circuit having a circuit width of 8 μm/inter-slice gap width of 8 μm is not easily formed by roughening treatment by conventionally known fine copper particles or reduction blackening treatment.

[Industrial Availability]

It is possible to completely remove the spatter existing around the opening of the hole formed by the laser drilling by using the copper foil with the carrier foil of the present application, thereby providing a clean copper layer. Copper clad laminate. As a result, it is possible to eliminate the defects caused by the sputtering, and to provide a high-quality multilayer printed circuit board. In addition, the copper foil provided with the carrier foil of the present application can be formed by a fine concavo-convex structure formed by a convex portion having a needle shape or a plate shape of a copper composite compound and having a maximum length of 500 nm or less. Then, the roughened layer of the carrier foil and the entire copper layer is formed to form a fine pitch circuit which is more than the above. Then, if the copper foil with a carrier foil of the present application is used, there is no need to change the manufacturing process of the conventional manufacturing method, and a multilayer printed circuit board can be produced by the build-up method or the coreless build-up method. High quality printed circuit board.

Claims (13)

A copper foil provided with a carrier foil, which is a copper foil provided with a carrier foil having a layer structure of a carrier foil/release layer/whole copper layer, and is characterized in that on both sides of the copper foil provided with the carrier foil A roughened layer having a fine concavo-convex structure formed of a needle-like or plate-like convex portion composed of a copper composite compound and having a maximum length of 100 nm or more and 500 nm or less is provided on the surface of the carrier foil. The roughened layer has the fine concavo-convex structure composed of a copper composite compound containing copper oxide as a main component, and is used as a laser light absorbing layer, and the roughened layer provided on the surface of the entire copper layer has oxidation-containing layer The fine concavo-convex structure composed of a copper composite compound of copper and cuprous oxide is used as a bonding layer between the roughened layer and the insulating layer material. The copper foil with a carrier foil according to the first aspect of the invention, wherein the peak area of Cu(I) obtained when the constituent elements of the fine concavo-convex structure are analyzed by X-ray photoelectron spectroscopy The ratio of the total area between the peak areas of Cu(II) and the peak area of Cu(I) is less than 50% as the roughening layer of the laser light absorbing layer, and is roughened as the bonding layer. The layer is 50% or more. The copper foil with a carrier foil according to the first aspect of the invention, wherein the roughening layer as the bonding layer has the fine concavo-convex structure composed of a copper composite compound containing cuprous oxide as a main component. A copper foil with a carrier foil as in claim 1 of the patent application, wherein When the roughened layer is observed at a magnification of 45° or more at a tilt angle of 45° or more with a scanning electron microscope, the convex portions that are adjacent to each other can be separated from the other convex portions and observed at the front end. The length of the part is below 250 nm. The copper foil with a carrier foil according to the fourth aspect of the invention, wherein the length of the front end portion of the convex portion is 1/2 or less with respect to the maximum length of the convex portion. A copper foil provided with a carrier foil 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 copper foil with a carrier foil according to the first aspect of the invention is characterized in that the brightness L* is 30 or less when the surface of the roughened layer is represented by the L*a*b* color system. The copper foil with a carrier foil according to claim 1, wherein the surface area when the secondary region of 57770 μm ² is measured by a laser method becomes a cubic surface area (A μm ² ) and the cubic surface area is relative to the foregoing When the ratio of the area of the secondary element region is B, the B of the roughening layer is 1.1 or more. The copper foil with a carrier foil according to the first aspect of the invention, wherein the surface roughness (Rzjis) of the bonding layer side of the entire copper layer is 2.0 μm or less. A copper foil provided with a carrier foil according to the first aspect of the invention, wherein the surface of the integral copper layer on the side of the bonding layer is subjected to a decane coupling agent treatment. A copper clad laminate, which is characterized in that it will be as in the first item of the patent application scope The bonding layer side of the entire copper layer of the copper foil with a carrier foil described above is laminated on at least one side of the insulating layer structural material. A printed circuit board comprising a copper layer formed by using the entire copper layer of a copper foil having a carrier foil as described in claim 1 of the patent application. The printed circuit board of claim 12, wherein the copper layer is provided with a via hole formed by laser drilling.