WO2016158775A1

WO2016158775A1 - Roughened copper foil, copper foil provided with carrier, copper-clad laminated sheet, and printed wiring board

Info

Publication number: WO2016158775A1
Application number: PCT/JP2016/059671
Authority: WO
Inventors: 浩人飯田; 光由松田; 吉川　和広; 信之河合; 翼加藤
Original assignee: 三井金属鉱業株式会社
Priority date: 2015-03-31
Filing date: 2016-03-25
Publication date: 2016-10-06
Also published as: CN107429417A; TWI620662B; TW201707948A; JP6293365B2; CN107429417B; KR102273442B1; KR20170132128A; JPWO2016158775A1; MY186266A

Abstract

Provided is a roughened copper foil which, when used in the SAP method, can endow a laminate with a surface profile excellent not only in plated circuit adhesion but also in etching performance for electroless copper plating and dry film resolution. This roughened copper foil has a roughened surface on at least one side, wherein: the roughened surface is provided with a plurality of substantially spherical projections composed of copper particles; the mean height of the substantially spherical projections is 2.60 μm or less; and the ratio b_ave/a_ave of the mean maximum diameter b_ave of the substantially spherical projections to the mean neck diameter a_ave of the substantially spherical projections is 1.2 or higher.

Description

Roughened copper foil, copper foil with carrier, copper clad laminate and printed wiring board

The present invention relates to a roughened copper foil, a copper foil with a carrier, a copper-clad laminate, and a printed wiring board.

In recent years, the SAP (semi-additive process) method has been widely adopted as a method for manufacturing a printed wiring board suitable for circuit miniaturization. The SAP method is a method suitable for forming an extremely fine circuit, and as an example, it is performed using a roughened copper foil with a carrier. For example, as shown in FIGS. 1 and 2, an ultrathin copper foil 10 having a roughened surface is used, and a prepreg 12 and a primer layer 13 are used on an insulating resin substrate 11 having a base substrate 11a and a lower layer circuit 11b. Then, the carrier foil (not shown) is peeled off, and then a via hole 14 is formed by laser drilling as necessary (step (b)). Next, the ultrathin copper foil is removed by etching to expose the primer layer 13 provided with the roughened surface profile (step (c)). After the electroless copper plating 15 is applied to the roughened surface (step (d)), it is masked with a predetermined pattern by exposure and development using the dry film 16 (step (e)), and the electrolytic copper plating 17 is applied. (Step (f)). After removing the dry film 16 to form the wiring portion 17a (step (g)), unnecessary electroless copper plating 15 between the

adjacent wiring portions

17a and 17a is removed by etching (step (h)). A wiring 18 formed in a predetermined pattern is obtained.

Thus, in the SAP method using the roughened copper foil, the roughened copper foil itself is removed by etching after laser drilling (step (c)). And since the uneven | corrugated shape of the roughening process surface of roughening process copper foil is transcribe | transferred to the laminated body surface from which the roughening process copper foil was removed, an insulating layer (for example, primer layer 13 or it is the same) in the subsequent process. In the absence, adhesion between the prepreg 12) and the plating circuit (for example, the wiring 18) can be secured. Note that the MSAP (Modified Semi-Additive Process) method that does not perform the copper foil removal step corresponding to step (c) is also widely used, but copper is used in the etching step (corresponding to step (h)) after development. Since the two layers of the foil layer and the electroless copper plating layer must be removed by etching, it is necessary to perform the etching deeper than the SAP method which only requires etching removal of one electroless copper plating layer. Therefore, it is necessary to make the circuit space somewhat narrower in consideration of a larger amount of etching, so that the MSAP method can be said to be somewhat inferior to the SAP method in terms of fine circuit formation. That is, the SAP method is more advantageous for the purpose of forming a finer circuit.

Meanwhile, a roughened copper foil with a carrier in which the shape of the roughened particles is controlled is known. For example, in Patent Document 1 (Japanese Patent Laid-Open No. 2013-199082), the average diameter D1 of the particle root at a position of 10% of the particle length is 0.2 μm to 1.0 μm on the surface of the ultrathin copper layer, A copper foil with a carrier characterized by having a roughened layer having a ratio L1 / D1 of the particle length L1 and the average diameter D1 of the particle root of 15 or less is disclosed. In Patent Document 1, the ratio D2 / D1 of the average diameter D2 of the center of the particle at the position of 50% of the particle length to the average diameter D1 of the particle root is 1 to 4 on the surface of the ultrathin copper layer, and the particle The ratio D2 / D3 of the average diameter D2 at the center and the particle tip D3 at a position of 90% of the particle length is preferably 0.8 to 1.0. Moreover, it is disclosed by the Example of patent document 1 that the length of a roughening particle | grain is 2.68 micrometers or more.

JP 2013-199082 A

As described above, in the SAP method using the roughened copper foil, the roughened copper foil itself is removed by etching after laser drilling (step (c)). And since the uneven | corrugated shape of the roughening process surface of roughening process copper foil is transcribe | transferred to the laminated body surface from which the roughening process copper foil was removed, an insulating layer (for example, primer layer 13 or it is the same) in the subsequent process. In the absence, adhesion between the prepreg 12) and the plating circuit (for example, the wiring 18) can be secured. However, since the surface profile suitable for improving the adhesion to the plating circuit tends to be rough unevenness in general, the etching property for the electroless copper plating tends to be lowered in the step (h). That is, as the electroless copper plating bites into rough irregularities, more etching is required to eliminate residual copper.

In the roughened copper foil having a roughened surface provided with a plurality of substantially spherical protrusions made of copper particles, the present inventors recently set the average height of the substantially spherical protrusions to 2.60 μm or less, and substantially When the ratio b _ave / a _ave of the average maximum diameter b _ave of the substantially spherical protrusions to the average neck diameter a _ave of the spherical protrusions is 1.2 or more, only excellent plating circuit adhesion is obtained when used in the SAP method. In addition, they obtained knowledge that a roughened copper foil can be provided that can impart a surface profile excellent in etching property to electroless copper plating to the laminate. Moreover, the knowledge that extremely fine dry film resolution was realizable was also acquired in the dry film image development process in SAP method by using the said roughening process copper foil.

Therefore, the object of the present invention is to provide a laminate with a surface profile that is excellent not only in plating circuit adhesion but also in etching performance for electroless copper plating and dry film resolution when used in the SAP method. Another object is to provide a roughened copper foil. Moreover, the other object of this invention is to provide the copper foil with a carrier provided with such a roughening process copper foil.

According to one aspect of the present invention, a roughened copper foil having a roughened surface on at least one side, the roughened surface comprising a plurality of substantially spherical protrusions made of copper particles, The average height of the substantially spherical protrusions is 2.60 μm or less, and the ratio b _ave / a _ave of the average maximum diameter b _ave of the substantially spherical protrusions to the average neck diameter a _ave of the substantially spherical protrusions is 1.2 or more. A roughened copper foil is provided.

According to another aspect of the present invention, a carrier foil, a release layer provided on the carrier foil, and the roughening treatment of the above aspect provided on the release layer with the roughening treatment surface facing outward. Provided is a copper foil with a carrier comprising a copper foil.

According to another aspect of the present invention, there is provided a copper clad laminate obtained using the roughened copper foil of the above aspect or the copper foil with a carrier of the above aspect.

According to another aspect of the present invention, there is provided a printed wiring board obtained using the roughened copper foil of the above aspect or the copper foil with a carrier of the above aspect.

It is a process flow chart for explaining the SAP method, and is a diagram showing the first half steps (steps (a) to (d)). It is a process flow chart for explaining the SAP method, and shows the latter half of the process (processes (e) to (h)). It is a schematic cross section which shows the substantially spherical particle in the roughening copper foil of this invention. It is a schematic cross section of the roughening copper foil which has the surface with the wave | undulation containing a high inclination substantially spherical particle. FIG. 4B is an enlarged cross-sectional view of a portion surrounded by a frame in FIG. 4A, for explaining the definition of highly inclined substantially spherical particles. It is a photograph which shows an example of the dry film pattern in which resolution was performed favorably in the SAP method. It is a photograph which shows an example of the dry film pattern in which resolution was not performed favorably in SAP method.

Definitions The definitions of terms and parameters used to specify the present invention are shown below.

In the present specification, the “substantially spherical protrusion” is a protrusion having a substantially spherical round shape, and is distinguished from an anisotropic shape protrusion or particle such as a needle shape, a columnar shape, and an elongated shape. is there. As schematically shown in FIG. 32, the substantially spherical protrusion 32 is connected to the copper foil surface 30 by the constricted root portion 34 connected to the copper foil surface 30, and thus cannot be a perfect sphere. However, parts other than the root part 32 should just be substantially spherical. Therefore, as long as the substantially spherical protrusion has a substantially spherical round shape, the presence of some unevenness or deformation is allowed. In addition, although the said protrusion may only be called a spherical protrusion, since it cannot become a perfect sphere as mentioned above, it should be understood as meaning the substantially spherical protrusion mentioned above.

In the present specification, the “neck diameter a of the substantially spherical protrusion” is the diameter of the narrow base portion 34 connected to the copper foil surface 30 in the substantially spherical protrusion 32, as schematically shown in FIG. It means the shortest distance between the constrictions. In addition, the “average neck diameter a _ave of the substantially spherical protrusion” is a surface profile of a rough replica-processed copper foil having a substantially spherical protrusion made of resin, and the surface of the obtained resin replica (for example, 435 μm ^2). ), The average value of the neck diameters a ₁ , a ₂ ,..., A _N of _N substantially spherical protrusions (that is, the value of (a ₁ + a ₂ +... + A _N ) / N). ). The production of the resin replica may be performed in accordance with various conditions described in the examples of the present specification.

In this specification, the “maximum diameter b of the substantially spherical protrusion” is the maximum diameter of the substantially spherical protrusion 32 measured in a direction parallel to the copper foil surface 30 as schematically shown in FIG. Further, the “average maximum diameter b _ave of approximately spherical protrusions” is the maximum diameter b ₁ , b ₂ ,... Of N approximately spherical protrusions measured on the surface of the roughened copper foil (for example, a region of 435 μm ² ). .., an average value of b _N (that is, a value of (b ₁ + b ₂ +... + B _N ) / N).

In this specification, the “substantially spherical protrusion height c” is based on the root portion 34 of the substantially spherical protrusion 32 measured in the direction perpendicular to the copper foil surface 30 as schematically shown in FIG. Height. The “average height c _ave of substantially spherical protrusions” is the heights c ₁ and c _{2 of} N substantially spherical protrusions measured in the cross-sectional profile of the roughened copper foil (for example, a reference length of 25 μm). ,..., C _{N is} an average value (that is, a value of (c ₁ + c ₂ +... + C _N ) / N).

In this specification, the “separate root d of substantially spherical protrusions” means a separation distance at the level of the root of adjacent substantially granular particles 30, that is, the roots of substantially granular particles 30, as schematically shown in FIG. 3. This is the shortest distance between the constriction of the portion 34 and the constriction of the root portion 34 of the adjacent substantially spherical particle 32. Further, the “average root separation distance d _ave of approximately spherical protrusions” means that a replica shape of a surface profile provided with approximately spherical protrusions of a roughened copper foil is made of a resin, and a resin replica surface obtained (for example, 435 μm) ² ), the average value of root separation distances d ₁ , d ₂ ,..., D _N−1 between N substantially spherical projections (ie, (d ₁ + d ₂ +... + D _{N− 1} ) / (N-1)). The production of the resin replica may be performed in accordance with various conditions described in the examples of the present specification.

In the present specification, the “highly inclined substantially spherical protrusion” means a root boundary line of the substantially spherical protrusion 32 (boundary line of the root portion 34) among the substantially spherical protrusions 32 as schematically shown in FIGS. 4A and 4B. the line L _VC connecting the midpoint C and the vertex V of substantially spherical projections 32, acute θ is 85 ° forming roughened surface of the roughened copper foil and the opposite face parallel to the reference line L _B is Refers to the following: In addition, the "ratio of the high-tilt substantially spherical protrusions occupying the total number of substantially spherical projections" were measured in the cross-section profile of the roughened copper foil (e.g. 10μm standard length), to the total number N _A substantially spherical projection The ratio of the number of highly inclined substantially spherical protrusions N _H , that is, 100 × N _H / N _A (%).

The neck diameter “a”, the maximum diameter “b”, and the root separation distance “d” of the substantially spherical protrusion are measured by subjecting an image acquired by SEM observation to image processing such as binarization processing using a commercially available image analysis device and software. be able to. As an example of such an image analysis apparatus, there is LUZEX AP manufactured by Nireco Corporation. The image processing may be performed according to various conditions described in the examples of the present specification.

In this specification, the “average distance between surface peaks (Peak spacing)” refers to a peak after removing a high-frequency swell component from information on unevenness of a sample surface obtained using a three-dimensional surface structure analysis microscope. The average distance between peaks in data extracted by filtering waveform data.

In this specification, “maximum waviness difference (Wmax)” means that waveform data relating to waviness is extracted from information relating to unevenness of the sample surface obtained using a three-dimensional surface structure analysis microscope using a filter. The maximum value of the height difference of the waveform data (the sum of the maximum peak height of the waveform and the maximum valley depth).

The average distance between peak peaks (Peak spacing) and the maximum difference in waviness (Wmax) are both commercially available three-dimensional surface structure analysis microscopes (for example, zygo New View 5032 (manufactured by Zygo)) and commercially available analysis software. (For example, Metro Pro Ver. 8.0.2) can be used with a low frequency filter set to 11 μm for measurement. At this time, the surface to be measured of the foil is fixed in close contact with the sample stage, and 6 fields of 108 μm × 144 μm are selected and measured within the 1 cm square range of the sample piece, and obtained from the 6 measurement points. The average value of the measured values obtained is preferably adopted as the representative value.

In this specification, the “electrode surface” of the carrier foil refers to the surface on the side in contact with the cathode when the carrier foil was produced.

In this specification, the “deposition surface” of the carrier foil refers to the surface on the side where electrolytic copper is deposited when the carrier foil is produced, that is, the surface not in contact with the cathode.

Roughened copper foil The copper foil according to the present invention is a roughened copper foil. This roughened copper foil has a roughened surface on at least one side. The roughened surface is provided with a plurality of substantially spherical protrusions 32 made of copper particles, as schematically shown in FIG. The average height c _ave of these substantially spherical protrusions 32 is 2.60 μm or less. Further, the ratio b _ave / a _ave of the average maximum diameter b _ave of the substantially spherical protrusion to the average neck diameter a _ave of the substantially spherical protrusion is 1.2 or more. Thus, in the roughened copper foil having a roughened surface provided with a plurality of substantially spherical protrusions made of copper particles, the average height c _ave of the substantially spherical protrusions is 2.60 μm or less, and the substantially spherical protrusions When the ratio b _ave / a _ave of the average maximum diameter b _ave of the substantially spherical protrusion to the average neck diameter a _ave is 1.2 or more, not only excellent plating circuit adhesion but also when used in the SAP method It is possible to provide a roughened copper foil capable of imparting a surface profile excellent in etching property to electroless copper plating to a laminate. In addition, by using the roughened copper foil, extremely fine dry film resolution can be realized in the dry film development step in the SAP method.

Plating circuit adhesion and etchability for electroless copper plating are inherently difficult to achieve at the same time, but according to the present invention, they can both be achieved unexpectedly. That is, as described above, since the surface profile suitable for improving the adhesion to the plating circuit tends to be rough unevenness, the etching property of the electroless copper plating is lowered in the step (h) of FIG. It's easy to do. That is, as the electroless copper plating bites into rough irregularities, more etching is required to eliminate residual copper. However, according to the roughened copper foil of the present invention, excellent plating circuit adhesion can be secured while realizing such a reduction in the etching amount. This is because the average height c _ave of the substantially spherical protrusions is set to be as low as 2.60 μm or less, thereby avoiding the above-described decrease in etching property due to the rough unevenness, while the average height c _ave of the substantially spherical protrusions is reduced. This is considered to be because the adhesiveness with the plating circuit, which is concerned with the decrease, can be improved by setting the ratio b _ave / a _ave to 1.2 or more. As can be understood from FIG. 3, the larger the ratio b _ave / a _ave , the more the substantially spherical protrusion 32 is constricted at the root portion 34 connected to the copper foil surface 30. In an insulating layer to which such a shape is transferred (for example, the primer layer 13 or the prepreg 12 when there is no such layer), an anchor effect based on the constricted shape derived from the substantially spherical protrusion 32 can be exhibited, and an excellent plating circuit and It is considered that the adhesion of the material can be realized. And it is thought that very fine dry film resolution can be realized in the dry film development process in the SAP method by satisfying both such excellent adhesion and excellent etching property for electroless copper plating. . Therefore, it is preferable that the roughened copper foil of this invention is used for preparation of the printed wiring board by a semi-additive method (SAP). In other words, it can be said that the roughened copper foil of the present invention is preferably used for transferring the concavo-convex shape to the insulating resin layer for the printed wiring board.

The roughened copper foil of the present invention has a roughened surface on at least one side. That is, the roughened copper foil may have a roughened surface on both sides, or may have a roughened surface only on one side. When both sides have roughened surfaces, the surface on the laser irradiation side (the surface opposite to the surface to be in close contact with the insulating resin) is also roughened when used in the SAP method. As a result, the laser drillability can be improved.

The roughened surface is provided with a plurality of substantially spherical protrusions 32, and the plurality of substantially spherical protrusions 32 are made of copper particles. That is, each substantially spherical protrusion 32 is basically composed of a single copper particle. The copper particles may be made of metallic copper, or may be made of a copper alloy. However, when the copper particles are a copper alloy, the solubility in the copper etching solution may decrease, or the life of the etching solution may decrease due to the alloy components mixed in the copper etching solution. Preferably it consists of.

The average height c _ave of the substantially spherical protrusion 32 is 2.60 μm or less, preferably 1.5 μm or less, more preferably 1.0 μm or less, and even more preferably 0.6 μm or less. Within these ranges, the etching property for electroless copper plating is significantly improved. Although the lower limit of the average height _{c ave} is is not particularly limited, the average height _{c ave} is preferably 0.2μm or more, and more preferably 0.4μm or more.

The ratio b _ave / a _ave of the average maximum diameter b _ave of the substantially spherical protrusion 32 to the average neck diameter a _ave of the approximately spherical protrusion 32 is 1.2 or more, preferably 1.2 to 5.0, more preferably 1 .3 to 3.0, more preferably 1.3 to 2.0, particularly preferably 1.4 to 1.7. Within these ranges, the anchor effect based on the constricted shape derived from the substantially spherical protrusion 32 can be sufficiently exhibited, and the plating circuit adhesion and the dry film resolution are improved.

The average neck diameter a _ave of the substantially spherical protrusion 32 is preferably 0.1 to 2.0 μm, more preferably 0.2 to 1.0 μm, and still more preferably 0.3 to 0.6 μm. When the average neck diameter a _ave is 2.0 μm or less, two or more substantially spherical protrusions can exist in the line width even in a fine circuit pattern of line / space (L / S) = 5 μm / 5 μm. Therefore, plating circuit adhesion and dry film resolution are improved.

The average maximum diameter b _ave of the substantially spherical protrusion 32 is preferably 2.5 μm or less, more preferably 0.2 to 2.5 μm, still more preferably 0.3 to 1.5 μm, and particularly preferably 0.4 to 1.2 μm, most preferably 0.4 to 0.8 μm. Within these ranges, the anchor effect based on the constricted shape derived from the substantially spherical protrusion 32 can be sufficiently exhibited, and the plating circuit adhesion and the dry film resolution are improved.

The ratio of the substantially spherical protrusion 32 in which the ratio b / a of the maximum diameter b of the substantially spherical protrusion 32 to the neck diameter a of the approximately spherical protrusion 32 occupies in the substantially spherical protrusion 32 existing on the roughened surface is 1.2 or more. It is preferably 60% or more, more preferably 70% or more, still more preferably 80% or more, and particularly preferably 90% or more on the number basis. Within these ranges, the anchor effect based on the constricted shape derived from the substantially spherical protrusion 32 can be sufficiently exhibited, and the plating circuit adhesion and the dry film resolution are improved.

The average root separation distance d of the substantially spherical protrusions 32 is preferably 0.10 to 0.30 μm, more preferably 0.15 to 0.25 μm. Within these ranges, the anchor effect based on the constricted shape derived from the substantially spherical protrusion 32 can be sufficiently exhibited, and the plating circuit adhesion and the dry film resolution are improved. .

The approximately spherical protrusions 32 are preferably present at an area density of 1 to 10 / μm ² , more preferably 2 to 5 / μm ² , and further preferably 3 to 5 / μm ² . Within these ranges, the anchor effect based on the constricted shape derived from the substantially spherical protrusion 32 can be sufficiently exhibited, and the plating circuit adhesion and the dry film resolution are improved. .

The roughened surface generally has waviness, and the substantially spherical protrusion 32 can be inclined due to this waviness. In particular, when the roughened copper foil has a roughened surface only on one side, the ratio of the highly inclined substantially spherical protrusions to the total number of substantially spherical protrusions 32 is preferably 30 to 60%, more preferably. It is 35 to 57%, more preferably 40 to 57%. High gradient substantially spherical protrusions, as described above, the line L _VC connecting the vertex V of substantially spherical midpoint C of the root boundary projections 32 and substantially spherical projection 32, the roughened surface of the roughened copper foil acute θ formed by the other side of the plane parallel to the reference line L _B is substantially spherical protrusions is 85 ° or less. When the ratio of the highly inclined substantially spherical protrusions is 60% or less, the roughened copper foil is etched away by the SAP method, and the unevenness derived from the roughened surface is given to the unevenness at the time of exposure. The resulting diffused reflection of light can be reduced and the dry film can be cured more advantageously, and as a result, the resolution of the dry film resist is further improved. Moreover, the adhesiveness with respect to a base material further improves that the ratio of a high inclination substantially spherical protrusion is 30% or more. Therefore, by setting the ratio of the highly inclined substantially spherical protrusions to 30 to 60%, it is possible to provide a roughened copper foil that is superior in achieving both dry film resolution and adhesion to the substrate.

The thickness of the roughened copper foil of the present invention is not particularly limited, but is preferably 0.1 to 18 μm, more preferably 0.5 to 10 μm, still more preferably 0.5 to 7 μm, and particularly preferably 0.5 to 5 μm, most preferably 0.5 to 3 μm. Note that the roughened copper foil of the present invention is not limited to the one obtained by subjecting the surface of the normal copper foil to the roughening treatment, but may be one obtained by subjecting the copper foil surface of the copper foil with carrier to the roughening treatment. Good.

Method for Producing Roughened Copper Foil An example of a preferred method for producing a roughened copper foil according to the present invention will be described. However, the roughened copper foil according to the present invention is not limited to the method described below, and the roughened copper foil according to the present invention is used. It may be manufactured by any method as long as the surface profile of the treated copper foil can be realized.

(1) Preparation of copper foil As copper foil used for manufacture of roughening processing copper foil, use of both electrolytic copper foil and rolled copper foil is possible. The thickness of the copper foil is not particularly limited, but is preferably 0.1 to 18 μm, more preferably 0.5 to 10 μm, still more preferably 0.5 to 7 μm, particularly preferably 0.5 to 5 μm, and most preferably 0. .5-3 μm. When the copper foil is prepared in the form of a copper foil with a carrier, the copper foil is prepared by a wet film formation method such as an electroless copper plating method and an electrolytic copper plating method, a dry film formation method such as sputtering and chemical vapor deposition, or It may be formed by a combination thereof.

The surface to be subjected to the roughening treatment of the copper foil before the roughening treatment is not particularly limited, but the maximum height difference (Wmax) of the waviness is preferably 6.0 μm or less, more preferably 0.8 μm. It is preferably 1 to 2.0 μm, more preferably 0.2 to 1.3 μm, and the average distance (Peak spacing) between surface peaks is preferably 100 μm or less, more preferably 3 to 70 μm, still more preferably 5 to 30 μm. In the case of Wmax and Peak spacing within such a range, the ratio of highly inclined substantially spherical protrusions to the total number of substantially spherical protrusions after the subsequent roughening treatment is preferably 30 to 60%, more preferably 35 to 57. %, More preferably 40 to 57%, can be conveniently formed. For example, when the copper foil is prepared in the form of a copper foil with a carrier, the realization of low peak spacing and Wmax within the above range is that the surface of the rotating cathode used when electrolytically forming the carrier foil is a baffle of a predetermined count. The surface roughness can be adjusted by polishing. That is, the surface profile of the rotating cathode thus adjusted is transferred to the electrode surface of the carrier foil, and the copper foil is formed on the electrode surface of the carrier foil thus provided with the desired surface profile via the release layer. The surface profile described above can be applied to the surface on which the foil is roughened (that is, the side opposite to the release layer). A preferred buff count is greater than # 1000 and less than # 3000, more preferably # 1500 to # 2500, and particularly preferably # 2000. Thus, by appropriately selecting the buff count within the above range, the undulation of the surface of the copper foil can be controlled, and the ratio of the highly inclined substantially spherical particles can be controlled as intended.

(2) Roughening treatment At least one surface of the copper foil is roughened using copper particles. This roughening is performed by electrolysis using a copper electrolytic solution for roughening treatment. This electrolysis is preferably performed through a two-step plating process. In the first plating process, a copper sulfate solution containing a copper concentration of 8 to 12 g / L and a sulfuric acid concentration of 200 to 280 g / L is used, the liquid temperature is 20 to 40 ° C., the current density is 15 to 35 A / dm ² , and the time is 5 Electrodeposition is preferably performed under plating conditions of ˜25 seconds. In the second plating step, a copper sulfate solution containing a copper concentration of 65 to 80 g / L and a sulfuric acid concentration of 200 to 280 g / L is used, the liquid temperature is 45 to 55 ° C., the current density is 5 to 30 A / dm ² , and the time is 5 Electrodeposition is preferably performed under plating conditions of ˜25 seconds. The amount of electricity in each stage is such that the ratio (Q ₁ / Q ₂ ) of the amount of electricity Q _{1 in} the first stage plating process to the amount of electricity Q ₂ in the second stage plating process is 1.5 to 2.5. It is preferable to set to. When the ratio Q ₁ / Q ₂ is less than 1.5, the constriction of the substantially spherical protrusion becomes small (that is, the ratio b / a becomes small), and the plating circuit adhesion can be lowered. On the other hand, when the ratio Q ₁ / Q ₂ exceeds 2.5, the constriction of the substantially spherical protrusion is increased (that is, the ratio b / a is increased), and the roughened particles are likely to fall off.

(3) Rust prevention treatment If desired, the copper foil after the roughening treatment may be subjected to a rust prevention treatment. The rust prevention treatment preferably includes a plating treatment using zinc. The plating treatment using zinc may be either a zinc plating treatment or a zinc alloy plating treatment, and the zinc alloy plating treatment is particularly preferably a zinc-nickel alloy treatment. The zinc-nickel alloy treatment may be a plating treatment containing at least Ni and Zn, and may further contain other elements such as Sn, Cr, and Co. The Ni / Zn adhesion ratio in the zinc-nickel alloy plating is preferably 1.2 to 10, more preferably 2 to 7, and still more preferably 2.7 to 4 in terms of mass ratio. The rust prevention treatment preferably further includes a chromate treatment, and this chromate treatment is more preferably performed on the surface of the plating containing zinc after the plating treatment using zinc. By carrying out like this, rust prevention property can further be improved. A particularly preferable antirust treatment is a combination of a zinc-nickel alloy plating treatment and a subsequent chromate treatment.

(4) Silane coupling agent treatment If desired, the copper foil may be treated with a silane coupling agent to form a silane coupling agent layer. Thereby, moisture resistance, chemical resistance, adhesiveness with an adhesive agent, etc. can be improved. The silane coupling agent layer can be formed by appropriately diluting and applying a silane coupling agent and drying. Examples of silane coupling agents include epoxy-functional silane coupling agents such as 4-glycidylbutyltrimethoxysilane and γ-glycidoxypropyltrimethoxysilane, or γ-aminopropyltriethoxysilane, N-β (amino Amino functions such as ethyl) γ-aminopropyltrimethoxysilane, N-3- (4- (3-aminopropoxy) butoxy) propyl-3-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane Silane coupling agent, or mercapto functional silane coupling agent such as γ-mercaptopropyltrimethoxysilane, or olefin functional silane coupling agent such as vinyltrimethoxysilane, vinylphenyltrimethoxysilane, or γ-methacryloxypropyl Trimetoki Acrylic-functional silane coupling agent such as a silane, or imidazole functional silane coupling agent such as imidazole silane, or triazine functional silane coupling agents such as triazine silane.

Copper foil with carrier The roughened copper foil of the present invention can be provided in the form of a copper foil with carrier. In this case, the carrier-attached copper foil includes a carrier foil, a release layer provided on the carrier foil, and the roughened copper foil of the present invention provided on the release layer with the roughened surface facing outside. It is equipped with. However, a known layer structure can be adopted as the carrier-attached copper foil except that the roughened copper foil of the present invention is used.

The carrier foil is a foil for supporting the roughened copper foil and improving its handleability. Examples of the carrier foil include an aluminum foil, a copper foil, a resin film whose surface is metal-coated, and the like, and preferably a copper foil. The copper foil may be a rolled copper foil or an electrolytic copper foil. The thickness of the carrier foil is typically 200 μm or less, preferably 12 μm to 35 μm.

The surface on the release layer side of the carrier foil preferably has a 10-point surface roughness Rzjis of 0.5 to 1.5 μm, more preferably 0.6 to 1.0 μm. Rzjis can be determined according to JIS B 0601: 2001. By giving such a ten-point surface roughness Rzjis to the surface of the carrier foil on the release layer side, a surface profile desirable for the roughened copper foil of the present invention produced via the release layer on the carrier foil is obtained. It can be made easier to apply.

The release layer is a layer having a function of weakening the peeling strength of the carrier foil, ensuring the stability of the strength, and further suppressing interdiffusion that may occur between the carrier foil and the copper foil during press molding at a high temperature. It is. The release layer is generally formed on one side of the carrier foil, but may be formed on both sides. The release layer may be either an organic release layer or an inorganic release layer. Examples of organic components used in the organic release layer include nitrogen-containing organic compounds, sulfur-containing organic compounds, carboxylic acids and the like. Examples of nitrogen-containing organic compounds include triazole compounds, imidazole compounds, and the like. Among these, triazole compounds are preferred in terms of easy release stability. Examples of triazole compounds include 1,2,3-benzotriazole, carboxybenzotriazole, N ′, N′-bis (benzotriazolylmethyl) urea, 1H-1,2,4-triazole and 3-amino- And 1H-1,2,4-triazole. Examples of the sulfur-containing organic compound include mercaptobenzothiazole, thiocyanuric acid, 2-benzimidazolethiol and the like. Examples of the carboxylic acid include monocarboxylic acid and dicarboxylic acid. On the other hand, examples of inorganic components used in the inorganic release layer include Ni, Mo, Co, Cr, Fe, Ti, W, P, Zn, and a chromate-treated film. The release layer may be formed by bringing a release layer component-containing solution into contact with at least one surface of the carrier foil and fixing the release layer component to the surface of the carrier foil. The contact of the carrier foil with the release layer component-containing solution may be performed by immersion in the release layer component-containing solution, spraying of the release layer component-containing solution, flowing down of the release layer component-containing solution, or the like. The release layer component may be fixed to the surface of the carrier foil by adsorption or drying of the release layer component-containing solution, electrodeposition of the release layer component in the release layer component-containing solution, or the like. The thickness of the release layer is typically 1 nm to 1 μm, preferably 5 nm to 500 nm.

The roughened copper foil of the present invention described above is used as the roughened copper foil. The roughening treatment of the present invention is performed by roughening using copper particles. As a procedure, first, a copper layer is formed as a copper foil on the surface of the release layer, and then at least roughening is performed. . Details of the roughening are as described above. In addition, it is preferable that copper foil is comprised with the form of an ultra-thin copper foil in order to utilize the advantage as copper foil with a carrier. A preferable thickness of the ultrathin copper foil is 0.1 μm to 7 μm, more preferably 0.5 μm to 5 μm, and still more preferably 0.5 μm to 3 μm.

Other functional layers may be provided between the release layer and the copper foil. An example of such another functional layer is an auxiliary metal layer. The auxiliary metal layer is preferably made of nickel and / or cobalt. The thickness of the auxiliary metal layer is preferably 0.001 to 3 μm.

Copper- clad laminate The roughened copper foil or carrier-attached copper foil of the present invention is preferably used for the production of a copper-clad laminate for printed wiring boards. That is, according to the preferable aspect of this invention, the copper clad laminated board obtained using the said roughening copper foil or the said copper foil with a carrier is provided. By using the roughened copper foil or the copper foil with carrier of the present invention, a copper clad laminate particularly suitable for the SAP method can be provided. This copper-clad laminate comprises the carrier-attached copper foil of the present invention and a resin layer provided in close contact with the roughened surface. The copper foil with a carrier may be provided on one side of the resin layer or may be provided on both sides. The resin layer comprises a resin, preferably an insulating resin. The resin layer is preferably a prepreg and / or a resin sheet. The prepreg is a general term for composite materials in which a base material such as a synthetic resin plate, a glass plate, a glass woven fabric, a glass nonwoven fabric, and paper is impregnated with a synthetic resin. Preferable examples of the insulating resin include an epoxy resin, a cyanate resin, a bismaleimide triazine resin (BT resin), a polyphenylene ether resin, and a phenol resin. Examples of the insulating resin that constitutes the resin sheet include insulating resins such as epoxy resins, polyimide resins, and polyester resins. Moreover, the filler particle etc. which consist of various inorganic particles, such as a silica and an alumina, may contain in the resin layer from a viewpoint of improving insulation. The thickness of the resin layer is not particularly limited, but is preferably 1 to 1000 μm, more preferably 2 to 400 μm, and still more preferably 3 to 200 μm. The resin layer may be composed of a plurality of layers. A resin layer such as a prepreg and / or a resin sheet may be provided on the ultrathin copper foil with a carrier via a primer resin layer previously applied to the surface of the copper foil.

Printed wiring board The roughened copper foil or carrier-attached copper foil of the present invention is preferably used for the production of a printed wiring board, particularly preferably for the production of a printed wiring board by a semi-additive method (SAP). That is, according to the preferable aspect of this invention, the printed wiring board obtained using the roughening process copper foil mentioned above or the said copper foil with a carrier is provided. By using the roughened copper foil or the copper foil with carrier according to the present invention, in the production of printed wiring boards, not only excellent plating circuit adhesion but also surface profile excellent in etching property for electroless copper plating is laminated. A roughened copper foil that can be applied to a body can be provided. In addition, by using the roughened copper foil, extremely fine dry film resolution can be realized in the dry film development step in the SAP method. Therefore, it is possible to provide a printed wiring board on which an extremely fine circuit is formed. The printed wiring board according to this aspect includes a layer configuration in which a resin layer and a copper layer are laminated in this order. In the case of the SAP method, the roughened copper foil of the present invention is removed in the step (c) of FIG. 1, and therefore the printed wiring board produced by the SAP method no longer contains the roughened copper foil of the present invention. Only the surface profile transferred from the roughened surface of the roughened copper foil remains. The resin layer is as described above for the copper-clad laminate. In any case, a known layer structure can be adopted for the printed wiring board. Specific examples of the printed wiring board include a single-sided or double-sided printed wiring board formed with a circuit on the laminated body obtained by bonding the ultrathin copper foil of the present invention to one side or both sides of the prepreg, and a multilayer in which these are multilayered. A printed wiring board etc. are mentioned. Other specific examples include a flexible printed wiring board, a COF, a TAB tape, and the like that form a circuit by forming the ultrathin copper foil of the present invention on a resin film. As another specific example, after forming the resin-coated copper foil (RCC) obtained by applying the above resin layer to the ultrathin copper foil of the present invention, and laminating the resin layer as an insulating adhesive layer on the above printed board , Build-up wiring board with ultra-thin copper foil as a whole or part of the wiring layer, modified semi-additive (MSAP) method, subtractive method, etc. Examples thereof include a build-up wiring board in which a circuit is formed by the (SAP) method, a direct build-up-on-wafer that alternately repeats the lamination of a copper foil with resin on a semiconductor integrated circuit and the circuit formation. As a more specific example, antenna elements formed by laminating the above resin-coated copper foil on a substrate to form a circuit, panels and electronic materials for panels and displays formed on a glass or resin film via an adhesive layer, and windows Examples thereof include an electronic material for glass, and an electromagnetic wave shielding film obtained by applying a conductive adhesive to the ultrathin copper foil of the present invention. In particular, the ultrathin copper foil with a carrier of the present invention is suitable for the SAP method. For example, when a circuit is formed by the SAP method, a configuration as shown in FIGS. 1 and 2 can be employed.

The present invention will be described more specifically by the following examples.

Examples 1-6
Production and evaluation of the roughened copper foil with carrier foil were performed as follows.

(1) Production of carrier foil A copper sulfate solution having the composition shown below as a copper electrolyte, and a rotating electrode made of titanium having an arithmetic average surface roughness Ra (based on JIS B 0601: 2001) of 0.20 μm as a cathode. Was used, and a DSA (dimensional stability anode) was used as an anode, and electrolysis was performed at a solution temperature of 45 ° C. and a current density of 55 A / dm ² , thereby obtaining an electrolytic copper foil having a thickness of 12 μm as a carrier foil. At this time, an electrode whose surface roughness was adjusted by polishing with a # 1000 buff was used as the rotating cathode. When the ten-point average roughness Rzjis of the surface of the obtained carrier foil on the electrode side was measured in accordance with JIS B 0601: 2001, it was 0.9 μm. Further, the ten-point average roughness Rzjis of the surface on the deposition side of the obtained carrier foil was 0.6 μm.
<Composition of copper sulfate solution>
-Copper concentration: 80 g / L
-Sulfuric acid concentration: 260 g / L
-Bis (3-sulfopropyl) disulfide concentration: 30 mg / L
-Diallyldimethylammonium chloride polymer concentration: 50 mg / L
-Chlorine concentration: 40 mg / L

(2) Formation of release layer The electrode surface side of the pickled copper foil for carrier was liquidized in a CBTA aqueous solution having a CBTA (carboxybenzotriazole) concentration of 1 g / L, a sulfuric acid concentration of 150 g / L, and a copper concentration of 10 g / L. It was immersed for 30 seconds at a temperature of 30 ° C., and the CBTA component was adsorbed on the electrode surface of the carrier foil. Thus, a CBTA layer was formed as an organic release layer on the surface of the electrode surface of the carrier copper foil.

(3) Formation of auxiliary metal layer The carrier copper foil on which the organic release layer is formed is immersed in a solution having a nickel concentration of 20 g / L prepared using nickel sulfate, and the liquid temperature is 45 ° C., pH 3, and the current density. Under the condition of 5 A / dm ² , nickel with a deposition amount corresponding to a thickness of 0.001 μm was deposited on the organic release layer. Thus, a nickel layer was formed as an auxiliary metal layer on the organic release layer.

(4) Ultra-thin copper foil formation A copper foil for carriers on which an auxiliary metal layer is formed is immersed in a copper sulfate solution having the composition shown below, and electrolysis is performed at a solution temperature of 50 ° C. and a current density of 5 to 30 A / dm ² . Then, an ultrathin copper foil having a thickness of 3 μm was formed on the auxiliary metal layer.
<Composition of solution>
-Copper concentration: 60 g / L
-Sulfuric acid concentration: 200 g / L

In Example 1, zygo New View 5032 (manufactured by Zygo) was used as the measuring instrument, and Metro Pro Ver. 8.0.2, using a low frequency filter under the condition of 11 μm, the maximum height difference (Wmax) of the waviness on the deposition surface (surface opposite to the auxiliary metal layer and the release layer) of the ultrathin copper foil ) And the average distance (Peak spacing) between the surface peaks. At this time, the ultra-thin copper foil was fixed in close contact with the sample stage, and measured by selecting 6 fields of 108 μm × 144 μm within the 1 cm square range of the sample piece, and obtained from 6 measurement points. The average value of the measured values was adopted as the representative value. As a result, the deposition surface (surface opposite to the release layer) of the ultrathin copper foil had a Wmax of 1.38 μm and a peak spacing of 21.37 μm.

(5) Roughening process The roughening process was performed with respect to the precipitation surface of the above-mentioned ultra-thin copper foil. This roughening treatment was performed by the following two-stage plating. In the first plating process, a copper sulfate solution containing a copper concentration of 10.0 to 11.5 g / L and a sulfuric acid concentration of 230 to 250 g / L is used, the liquid temperature is 20 to 40 ° C., and the current density is 10 to 25 A / dm. Electrodeposition was performed under the plating conditions of ² . In the second plating step, a copper sulfate solution containing a copper concentration of 65 to 75 g / L and a sulfuric acid concentration of 230 to 250 g / L is used, and the plating temperature is 50 to 55 ° C. and the current density is 5 to 15 A / dm ² . I electrodeposited. The amount of electricity at each stage is 2.1 (Example 1) in which the ratio (Q ₁ / Q ₂ ) of the amount of electricity Q _{1 in} the first stage plating process to the amount of electricity Q ₂ in the second stage plating process is 2.1 (Example 1). 8 (Example 2), 2.4 (Example 3), 1.9 (Example 4), 1.7 (Example 5), 1.6 (Example 6) or 1.2 (Example 7) did. Six types of roughened copper foils of Examples 1 to 6 were prepared by appropriately varying the conditions within the above range.

(6) Rust prevention treatment Rust prevention treatment comprising inorganic rust prevention treatment and chromate treatment was performed on both surfaces of the ultrathin copper foil with carrier foil after the roughening treatment. First, as an inorganic rust prevention treatment, using a pyrophosphate bath, potassium pyrophosphate concentration 80 g / L, zinc concentration 0.2 g / L, nickel concentration 2 g / L, liquid temperature 40 ° C., current density 0.5 A / dm ² Zinc-nickel alloy rust prevention treatment was performed. Next, as a chromate treatment, a chromate layer was further formed on the zinc-nickel alloy rust preventive treatment. This chromate treatment was performed at a chromic acid concentration of 1 g / L, pH 11, a solution temperature of 25 ° C., and a current density of 1 A / dm ² .

(7) Silane coupling agent treatment The copper foil that has been subjected to the above rust prevention treatment is washed with water and then immediately treated with a silane coupling agent to adsorb the silane coupling agent on the rust prevention treatment layer of the roughened surface. It was. In this silane coupling agent treatment, pure water is used as a solvent, a solution having a 3-aminopropyltrimethoxysilane concentration of 3 g / L is used, and this solution is sprayed onto the roughened surface by showering to perform an adsorption treatment. went. After adsorption of the silane coupling agent, moisture was finally diffused by an electric heater to obtain a copper foil with a carrier having a roughened copper foil having a thickness of 3 μm.

(8) Evaluation of roughened copper foil About the obtained roughened copper foil, the various characteristics of the surface profile containing a substantially spherical protrusion were performed as follows.

<Measurement of neck diameter a and root separation distance d>
The surface profile of the roughened copper foil having a substantially spherical protrusion is made of a resin, and the surface profile of the obtained resin replica is observed with an SEM, and image analysis is performed. And the average root separation distance d were measured. The specific procedure is as follows. First, a copper foil with a carrier and a prepreg (manufactured by Mitsubishi Gas Chemical Company, Inc., GHPL-830NSF, thickness 0.1 mm) were thermocompression bonded to produce a copper-clad laminate. Then, after peeling off the carrier of the copper foil with a carrier, the roughened copper foil was removed by etching. The surface on which the surface profile of the cured prepreg (that is, resin replica) thus transferred was transferred was subjected to SEM observation (5000 times), and image analysis was performed using an image analyzer (LUZEX AP, manufactured by Nireco Corporation). For the region of 435 μm ^2, the neck diameter a and the root separation distance d were measured, and the average values thereof (that is, the average neck diameter a _ave and the average root separation distance d _ave ) were obtained.

The specific image analysis procedure was as follows. First, an image photographed by SEM was binarized (threshold value 0 to 110) by image processing software. In order to separate the bonded particles in the binarized image thus obtained, a circular cut-out process was performed using a logical filter. Next, after removing the noise of the outline by the smoothing process, the minute particles as noise were removed by the logic filter. Thereafter, the neck diameter a and the root separation distance d were calculated for each detected particle. The conditions adopted in each treatment were as follows.
-Binarization processing: Threshold value 0 to 110 (The binarization threshold value that can be set in the image processing software is 0 to 255. 0 corresponds to perfect black, and 255 corresponds to complete white.)
-Logical filter circular cutout: 6 (degree)
-Logical particle size cut: 0.03μm ² or less

<Measurement of maximum diameter b>
The surface profile of the roughened copper foil with substantially spherical protrusions was observed with an SEM (5000 magnifications) and image analysis was performed using an image analyzer (LUZEX_AP, manufactured by Nireco Corporation). For the region of 435 μm ² , the maximum diameter b of the substantially spherical protrusions was measured, and the average value thereof (that is, average maximum diameter b _ave ) was determined.

The specific image analysis procedure was as follows. First, an image photographed by SEM was subjected to spatial filter processing by image processing software. This spatial filter processing was performed by enhancing the contour line with a Laplacian filter after reducing the noise of the original image by averaging. Next, the image was binarized (threshold values 64 to 165). The contour line of the binarized image thus obtained was expanded so that one approximately spherical protrusion was recognized as one particle. And in order to isolate | separate particles, the circular cut-out process was implemented with the logic filter. Next, after removing the noise of the outline by the smoothing process, the minute particles as noise were removed by the logic filter. Thereafter, the average maximum diameter b was calculated for each detected particle. The conditions adopted in each treatment were as follows.
-Binarization processing: threshold value 64 to 145 (the binarization threshold value that can be set in the image processing software is 0 to 255. 0 corresponds to perfect black, and 255 corresponds to complete white.)
-Logic filter specified size particle removal: 0.05μm ²
-Logical filter circular segmentation: 10 (degree)
-Logic filter specified size particle removal: 0.05μm ²

<Measurement of height c>
A cross section is prepared from the surface of the roughened copper foil by FIB (Focused Ion Beam) processing, the cross section is observed with SEM (5000 times), and the reference length in the foil surface direction (direction perpendicular to the thickness direction) The height of each substantially spherical protrusion in the range of 25 μm was measured.

<Measurement of tilt angle of substantially spherical particles>
In Example 1, the roughened copper foil was pressed and bonded to a prepreg (manufactured by Mitsubishi Gas Chemical Company, Inc., GHPL-830NSF, thickness 0.1 mm) on the roughened surface side. A cross section is produced from the surface of the roughened copper foil by CP (cross section polisher) processing, the cross section is observed with an SEM, and the reference length is 10 μm in the foil surface direction (direction perpendicular to the thickness direction). The inclination angle of each of the substantially spherical protrusions was measured. Specifically, first, as shown in FIG. 4A, in the cross-sectional SEM image observed by SEM at a low magnification (for example, 5000 times) so that the entire copper foil enters the field of view, the side opposite to the roughened surface of the copper foil minus the reference line L _B parallel to the surface. Because the surface of the roughened surface opposite to a relatively flat surface roughening treatment is not performed, the reference line L _B in the low magnification can be drawn as a straight line. Next, as shown in FIG. 4B, enlarged magnification SEM 10,000 times, the reference length range of 10μm baseline _{L B} of enlarged cross-sectional SEM image, the root boundary substantially spherical projections draw a line L _VC connecting the midpoint C and the vertex V of the substantially spherical protrusions, substantially spherical projections acute angle and the line L _VC and the reference line L _B is 85 ° or less, a percentage of the total number of substantially spherical projections A was calculated. Similarly, the ratio A was calculated for the other two visual fields of the roughened surface, and the average value of the ratios A calculated for a total of three visual fields was adopted.

(9) Production of copper-clad laminate A copper-clad laminate was produced using an ultrathin copper foil with a carrier. First, an ultrathin copper foil with a carrier is laminated on the surface of the inner layer substrate via a prepreg (manufactured by Mitsubishi Gas Chemical Co., Ltd., GHPL-830NSF, thickness 0.1 mm), and a pressure of 4.0 MPa, After thermocompression bonding at a temperature of 220 ° C. for 90 minutes, the carrier foil was peeled off to produce a copper clad laminate.

(10) Production of Laminated Body for SAP Evaluation Next, all the copper foil on the surface of the copper-clad laminate was removed with a sulfuric acid / hydrogen peroxide-based etching solution, and then degreasing, Pd-based catalyst application, and activation treatment were performed. The surface thus activated was subjected to electroless copper plating (thickness: 1 μm) to obtain a laminate (hereinafter referred to as “SAP evaluation laminate”) immediately before the dry film was laminated by the SAP method. These steps were performed according to known conditions of the SAP method.

(11) Evaluation of Laminated Body for SAP Evaluation Various characteristics of the obtained laminated body for SAP evaluation were evaluated as follows.

<Plating circuit adhesion (peel strength)>
A dry film was laminated to the laminate for SAP evaluation, and exposure and development were performed. After depositing a copper layer having a thickness of 19 μm by pattern plating on the laminate masked with the developed dry film, the dry film was peeled off. The electroless copper plating exposed by the sulfuric acid / hydrogen peroxide etching solution was removed, and a sample for measuring peel strength having a height of 20 μm and a width of 10 mm was prepared. In accordance with JIS C 6481 (1996), the peel strength when the copper foil was peeled from the sample for evaluation was measured.

<Etching property>
The laminate for SAP evaluation was etched by 0.1 μm with a sulfuric acid / hydrogen peroxide etching solution, and the amount (depth) until copper on the surface was completely removed was measured. The measuring method was confirmed with an optical microscope (500 times). More specifically, each time 0.1 μm etching was performed, the operation of checking with or without copper was repeated with an optical microscope, and the value (μm) obtained by (number of etchings) × 0.1 μm was used as an index of etching property. For example, an etching property of 1.2 μm means that residual copper is no longer detected by an optical microscope after performing 0.1 μm etching 12 times (that is, 0.1 μm × 12 times = 1.2 μm). ). That is, as this value is smaller, it means that copper on the surface can be removed by a smaller number of etchings. That is, the smaller this value, the better the etching property.

<Dry film resolution (minimum L / S)>
A dry film having a thickness of 25 μm was laminated on the surface of the laminate for SAP evaluation, and exposure and development were performed using a mask in which a line / space (L / S) pattern of 2 μm / 2 μm to 15 μm / 15 μm was formed. . The exposure amount at this time was set to 125 mJ. The surface of the sample after development was observed with an optical microscope (500 times), and the smallest (that is, the finest) L / S in the L / S that could be developed without any problem was adopted as an index for the resolution of the dry film. For example, the minimum L / S = 10 μm / 10 μm, which is an index for evaluating the dry film resolution, means that the resolution could be achieved without any problem from L / S = 15 μm / 15 μm to 10 μm / 10 μm. For example, when the resolution can be performed without any problem, a clear contrast is observed between the dry film patterns as shown in FIG. 5, whereas when the resolution is not performed well, the resolution is shown in FIG. Thus, a darkened portion is observed between the dry film patterns, and no clear contrast is observed.

Example 7 (Comparison)
Other than the ratio (Q ₁ / Q ₂ ) of the amount of electricity Q _{1 in} the first step plating step to the amount of electricity Q ₂ in the second step plating step (Q ₁ / Q ₂ ) in the roughening treatment. Prepared and evaluated roughened copper foil with carrier in the same manner as described in Examples 1-6.

Example 8 (Comparison)
Roughened copper with carrier in the same manner as described with respect to Examples 1 to 6 except that the roughening treatment was performed according to the following procedure according to Example 2 of Patent Document 1 (Japanese Patent Laid-Open No. 2013-199082). Preparation and evaluation of foil were performed.

(Roughening treatment)
Roughening was performed by performing roughening plating using a plating solution having the following liquid composition. At this time, the ratio of the limiting current density during the formation of roughened particles was 3.10, and the electroplating temperature was 50 ° C. <Composition of plating solution for roughening treatment>
-Cu: 15 g / L
-H ₂ SO ₄ : 100 g / L
-W: 3mg / L
-Sodium dodecyl sulfate addition amount: 10ppm

Example 9
A roughened copper foil with a carrier was prepared and evaluated in the same manner as in Example 1 except that an electrode whose surface was polished by adjusting the surface with a # 2000 buff was used as the rotating cathode. In addition, as for the precipitation surface of the ultra-thin copper foil before a roughening process, Wmax was 1.00 micrometer and Peak spacing was 20.28 micrometers.

Example 10
Preparation and evaluation of the roughened copper foil with carrier were performed in the same manner as in Example 1 except that the organic release layer was formed on the deposition surface side of the carrier copper foil. The precipitation surface of the ultrathin copper foil before the roughening treatment had a Wmax of 0.71 μm and a peak spacing of 52.13 μm.

Results The evaluation results obtained in Examples 1 to 10 were as shown in Tables 1 and 2.

As shown in Table 1, all of Examples 1 to 6 were good in plating circuit adhesion, etching property, and dry film resolution. On the other hand, as shown in Table 2, in Example 7 (comparison), which is out of the scope of the present invention because the a _ave / b _ave ratio is low, the adhesion of the plating circuit is poor and the dry film resolution is also poor. there were. Moreover, in Example 8 (comparison) which is outside the scope of the present invention because of the high average height c _ave , the etching property was inferior. In addition, Example 9 in which the ratio of the highly inclined substantially spherical protrusions is in the range of 30 to 60% is superior to Examples 1 and 10 outside the above range in terms of both dry film resolution and plating circuit adhesion. It was a thing.

Claims

A roughened copper foil having a roughened surface on at least one side, wherein the roughened surface comprises a plurality of substantially spherical protrusions made of copper particles, and the average height of the substantially spherical protrusions is 2 A roughened copper foil having a ratio b ave / a ave of not more than 60 μm and a ratio of the average maximum diameter b ave of the substantially spherical protrusions to the average neck diameter a ave of the substantially spherical protrusions being 1.2 or more.
The roughened copper foil according to claim 1, wherein the ratio b ave / a ave is 5.0 or less.
The roughened copper foil according to claim 1 or 2, wherein the ratio b ave / a ave is 1.3 to 2.0.
The roughened copper foil according to any one of claims 1 to 3, wherein an average maximum diameter b ave of the substantially spherical protrusion is 2.5 µm or less.
The ratio of the substantially spherical protrusions in which the ratio b / a of the maximum diameter b of the substantially spherical protrusions to the neck diameter a of the substantially spherical protrusions occupies in the substantially spherical protrusions existing on the roughened surface is 60% or more. The roughened copper foil according to any one of claims 1 to 4, which is as described above.
The roughened copper foil according to any one of claims 1 to 5, wherein an average root separation distance of the substantially spherical protrusions is 0.1 to 0.3 µm.
The roughened copper foil according to any one of claims 1 to 6, wherein the substantially spherical protrusions are present at a surface density of 1 to 10 pieces / μm 2 .
The roughened copper foil has the roughened surface only on one side, and the ratio of the highly inclined substantially spherical protrusions to the total number of the approximately spherical protrusions is 30 to 60%, and the high inclined substantially The spherical protrusion is a line connecting the midpoint of the base boundary line of the substantially spherical protrusion and the apex of the substantially spherical protrusion, and a reference line parallel to the surface opposite to the roughened surface of the roughened copper foil. The roughened copper foil according to any one of claims 1 to 7, which is a substantially spherical protrusion having an acute angle of 85 ° or less.
The roughened copper foil according to any one of claims 1 to 8, wherein the roughened copper foil has a thickness of 0.5 to 5 µm.
The roughened copper foil according to any one of claims 1 to 9, which is used for transferring an uneven shape to an insulating resin layer for a printed wiring board.
The roughened copper foil according to any one of claims 1 to 10, which is used for production of a printed wiring board by a semi-additive method (SAP).
A roughened copper according to any one of claims 1 to 11, provided with a carrier foil, a release layer provided on the carrier foil, and the release surface with the roughened surface facing outside. A copper foil with a carrier provided with a foil.
A copper-clad laminate obtained using the roughened copper foil according to any one of claims 1 to 11 or the copper foil with a carrier according to claim 12.
A printed wiring board obtained using the roughened copper foil according to any one of claims 1 to 11 or the copper foil with carrier according to claim 12.