CN109072472B

CN109072472B - Surface-treated copper foil, copper foil with carrier, and copper-clad laminate and printed wiring board manufacturing method using same

Info

Publication number: CN109072472B
Application number: CN201780023464.6A
Authority: CN
Inventors: 加藤翼; 松田光由; 饭田浩人; 吉川和广
Original assignee: Mitsui Mining and Smelting Co Ltd
Current assignee: Mitsui Mining and Smelting Co Ltd
Priority date: 2016-04-14
Filing date: 2017-03-28
Publication date: 2020-10-16
Anticipated expiration: 2037-03-28
Also published as: MY186859A; JP6945523B2; WO2017179416A1; KR102338103B1; CN109072472A; JPWO2017179416A1; KR20180133845A; TW201742212A; TWI711139B

Abstract

Provided is a surface-treated copper foil which, when used in an SAP process, can impart to a laminate a surface profile which is excellent not only in adhesion to a plated circuit but also in etching properties for electroless copper plating and dry film resolution. The surface-treated copper foil has a treated surface on at least one side. The arithmetic mean curvature Spc of the peak apex of the treated surface, determined in accordance with ISO25178, is 55mm^‑1When the resin film is thermally pressed against the treated surface to transfer the surface shape of the treated surface to the surface of the resin film and the surface-treated copper foil is removed by etching as described above, the arithmetic mean curvature Spc of the peak top of the surface of the remaining resin film measured in accordance with ISO25178 is 55mm^‑1The above.

Description

Surface-treated copper foil, copper foil with carrier, and copper-clad laminate and printed wiring board manufacturing method using same

Technical Field

The present invention relates to a surface-treated copper foil, a copper foil with a carrier, and a method for producing a copper-clad laminate and a printed wiring board using the same.

Background

In recent years, as a manufacturing process of a printed wiring board suitable for miniaturization of a circuit, a semi-additive process (SAP process) is widely used. The SAP method is a method extremely suitable for forming a fine circuit, and is performed using a copper foil with a roughened carrier as an example. For example, as shown in fig. 1 and 2, an extra thin copper foil 10 having a roughened surface is pressure-bonded and adhered to an insulating resin substrate 11 by using a prepreg 12 and a primer layer 13, the insulating resin substrate 11 being an insulating resin substrate having a lower circuit 11b on a base substrate 11a (step (a)); after the carrier (not shown) is peeled off, via holes 14 are formed by laser punching as necessary (step (b)). Next, the extra thin copper foil is removed by etching, thereby exposing the primer layer 13 having the roughened surface profile (step (c)). After electroless copper plating 15 is applied to the roughened surface (step (d)), masking is performed in a predetermined pattern by exposure and development using a dry film 16 (step (e)), and electrolytic copper plating 17 is applied (step (f)). After the dry film 16 is removed to form the wiring portions 17a (step (g)), unnecessary electroless copper plating 15 between the

adjacent wiring portions

17a, 17a is removed by etching (step (h)), thereby obtaining the wiring 18 formed in a predetermined pattern.

In the SAP method using the roughened copper foil, the roughened copper foil itself is removed by etching after laser piercing (step (c)). Further, since the uneven shape of the roughened surface of the roughened copper foil is transferred to the surface of the laminate from which the roughened copper foil has been removed, adhesion between the insulating layer (for example, the primer layer 13 or the prepreg 12 in the absence thereof) and the plated circuit (for example, the wiring 18) can be ensured in the subsequent steps. Also, a simulated semi-additive process (MSAP process) is widely used which does not perform a copper foil removal process corresponding to the process (c), but since 2 layers of the copper foil layer and the electroless copper plating layer must be removed by etching in an etching process (corresponding to the process (h)) after the dry film removal, it is necessary to perform deeper etching than the SAP process in which only the electroless copper plating layer 1 is etched and removed. Therefore, considering that the circuit interval needs to be reduced to some extent in consideration of a larger etching amount, the MSAP method can be said to be inferior to the SAP method in terms of fine circuit formability. That is, the SAP method is more advantageous for the purpose of finer circuit formation.

On the other hand, a roughened carrier-treated copper foil in which the shape of the roughened particles is controlled is known. For example, patent document 1 (jp 2013 a 199082) discloses a copper foil with carrier, which is characterized in that the surface of an extra thin copper layer has a roughened layer in which the average diameter D1 of the root of a particle at a position of 10% of the particle length is 0.2 to 1.0 μm and the ratio L1/D1 of the particle length L1 to the average diameter D1 of the root of the particle is 15 or less. In patent document 1, it is preferable that the ratio D2/D1 of the average diameter D2 of the center of the particle at a position 50% of the length of the particle to the average diameter D1 of the root of the particle on the surface of the extremely thin copper layer is 1 to 4, and the ratio D2/D3 of the average diameter D2 of the center of the particle to the particle front end D3 at a position 90% of the length of the particle is 0.8 to 1.0. In addition, in the examples of patent document 1, it is disclosed that the length of the grained particles is 2.68 μm or more.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2013-199082

Disclosure of Invention

As described above, in the SAP method using the roughened copper foil, the roughened copper foil itself is removed by etching after laser piercing (step (c)). Further, the roughened surface of the roughened copper foil is transferred to the surface of the laminate from which the roughened copper foil has been removed, thereby giving a double-type roughened surface. By doing so, adhesion between the insulating layer (for example, the primer layer 13 or the prepreg 12 in the absence thereof) and the plated circuit (for example, the wiring 18) can be ensured in the subsequent steps. However, in order to cope with further miniaturization of circuits, further improvement of adhesion is desired. Therefore, it is considered that the adhesion can be improved by utilizing the anchoring effect of the corresponding replica concave-convex shape by sinking into the concave portion with the intermediate thinning, by making the concave-convex shape of the roughened surface into a shape having a substantially spherical protrusion with the intermediate thinning. However, in this case, in the electroless copper plating in the step (d), the concave portion of the composite uneven shape may be buried by the copper plating layer, or the intermediate portion of the composite uneven shape may be closed by the copper plating layer and flattened. Such burying or flattening of the replica concave-convex shape leads to a decrease in dry film resolution and etching property. That is, the dry film is less likely to sink into the replica concave-convex shape, resulting in a decrease in adhesion to the dry film and a decrease in dry film resolution. Further, more etching is required to remove the thinned concave portion of the electroless copper plating-embedded complex type uneven shape and to remove the residual copper.

The inventors of the present invention have obtained the following findings: by providing a specific surface profile defined by the arithmetic mean curvature of peak top Spc measured in accordance with ISO25178 to the treated surface of the surface-treated copper foil, it is possible to provide a surface-treated copper foil which can provide a laminate with a surface profile excellent not only in the adhesion of a plated circuit but also in the etching property for electroless copper plating when used in the SAP method. In addition, the following findings were obtained: by using the surface-treated copper foil, an extremely fine dry film resolution can be achieved in the dry film developing step in the SAP method.

Accordingly, an object of the present invention is to provide a surface-treated copper foil which can impart a surface profile excellent not only in adhesion to a plated circuit but also in etching properties for electroless copper plating and dry film resolution to a laminate when used in an SAP method. Another object of the present invention is to provide a copper foil with carrier, which includes such a surface-treated copper foil.

According to one embodiment of the present invention, there is provided a surface-treated copper foil having a treated surface on at least one side,

the arithmetic mean curvature Spc of the peak apex of the aforementioned treated surface, determined in accordance with ISO25178, is 55mm^-1In the above-mentioned manner,

thermally pressing a resin film to the treated surface to transfer the surface shape of the treated surface to the surface of the resin filmAnd the arithmetic mean curvature Spc of the peak top of the surface of the resin film remaining when the surface-treated copper foil is removed by etching is 55mm as measured in accordance with ISO25178^-1The above.

According to another embodiment of the present invention, there is provided a copper foil with carrier, including: a carrier; a peeling layer provided on the carrier; and the surface-treated copper foil provided on the release layer with the treated surface as an outer side.

According to another embodiment of the present invention, there is provided a method for manufacturing a copper-clad laminate, wherein the surface-treated copper foil or the copper foil with a carrier is used to manufacture the copper-clad laminate.

According to another embodiment of the present invention, there is provided a method for manufacturing a printed wiring board, comprising manufacturing a printed wiring board using the surface-treated copper foil or the copper foil with a carrier.

Drawings

Fig. 1 is a process flow chart for explaining the SAP method, and is a diagram showing the first half steps (a) to (d)).

Fig. 2 is a process flow chart for explaining the SAP method, and is a diagram showing the latter half of the processes (e) to (h)).

Fig. 3 is a diagram for explaining a load curve and a load area ratio determined in accordance with ISO 25178.

Fig. 4 is a diagram for explaining a load area ratio Smr1 determined in accordance with ISO25178 for separating a projected peak from a central portion.

Detailed Description

Definition of

The following shows definitions of terms or parameters used to define the present invention.

In the present specification, the "arithmetic mean curvature Spc of the peak top" is a parameter indicating the arithmetic mean of the principal curvatures of the peak top of the surface measured in accordance with ISO 25178. A small value indicates a point of contact with another object. On the other hand, a large value indicates a sharp point of contact with another object. In short, the arithmetic mean curvature Spc of the peak apex can be said to be measurable with a laser microscopeA parameter indicating the roundness of the convex portion is determined. The arithmetic mean curvature Spc of the peak apex can be determined by measuring the predetermined measurement area (for example, 100 μm) of the treated surface by a commercially available laser microscope²Two-dimensional region of (d) is measured and calculated. Spc is defined by the following equation.

In the present specification, the "load curve of a surface" (hereinafter, simply referred to as "load curve") is a curve representing a height at which a load area ratio is changed from 0% to 100%, measured in accordance with ISO 25178. As shown in fig. 3, the load area ratio is a parameter indicating the area of a region having a certain height c or more. The load area ratio at height c is equivalent to smr (c) in fig. 3. As shown in fig. 4, a position where a secant line of the load curve drawn from the load area ratio of 0% along the load curve with the difference in load area ratio of 40% starts to move from the load area ratio of 0% and the slope of the tangent line becomes the most gentle is referred to as a central portion of the load curve. The straight line having the smallest square sum of the deviations in the longitudinal axis direction with respect to the central portion is referred to as an equivalent straight line. The portion included in the range of 0% to 100% of the height of the load area ratio of the straight equivalent line is referred to as the center portion. The portion higher than the central portion is referred to as a projecting peak, and the portion lower than the central portion is referred to as a projecting valley. The center part indicates the height of the region that comes into contact with another object after the initial wear is completed.

In the present specification, as shown in fig. 4, the "load area ratio Smr1 separating the projected ridge portions from the central portion" is a parameter indicating a load area ratio at the intersection of the upper height of the central portion and the load curve (i.e., a load area ratio separating the central portion and the projected ridge portions) measured in accordance with ISO 25178. The larger the value, the larger the proportion of the projecting peaks occupied. In fig. 4, Sk represents the height of the central portion, and Smr2 represents the load area ratio separating the central portion and the protruding valley portions. The ratio Smr1 of the load area separating the projected ridge portion from the central portion can be determined by measuring the predetermined measurement area of the treated surface with a commercially available laser microscope (for example, 100)μm²Area) of the surface of the object is measured.

In the present specification, the "peak top density Spd" is a parameter indicating the number of peak tops per unit area measured in accordance with ISO 25178. When the value is large, it indicates that the number of contact points with other objects is large. The peak density Spd can be determined by measuring the predetermined area (for example, 100 μm) of the treated surface by a commercially available laser microscope²Area (d) was measured and calculated.

In the present specification, the "electrode surface" of the electrolytic copper foil refers to a surface which is in contact with a cathode when the electrolytic copper foil is produced.

In the present specification, the "deposition surface" of the electrolytic copper foil means a surface on which electrolytic copper is deposited in the production of the electrolytic copper foil, that is, a surface not in contact with a cathode.

Surface treated copper foil

The copper foil of the present invention is a surface-treated copper foil. The surface-treated copper foil has a treated surface on at least one side. The arithmetic mean curvature Spc of the peak apex of the treated surface, determined in accordance with ISO25178, is 55mm^-1The above. In addition, in the surface-treated copper foil, when the resin film is thermally pressed against the treated surface to transfer the surface shape of the treated surface to the surface of the resin film and the surface-treated copper foil is removed by etching, the arithmetic mean curvature Spc of the peak top (hereinafter, also referred to as transfer surface) of the surface (hereinafter, also referred to as resin replica) of the remaining resin film (hereinafter, also referred to as transfer surface) is 55mm as measured in accordance with ISO25178^-1The above. As described above, by providing the treated surface of the surface-treated copper foil with a specific surface profile defined by the arithmetic mean curvature of peak top Spc measured in accordance with ISO25178, it is possible to provide a surface-treated copper foil which can provide a laminate with a surface profile excellent not only in the adhesion of a plated circuit but also in the etching property for electroless copper plating when used in the SAP method. Further, by using the surface-treated copper foil, an extremely fine dry film resolution can be achieved in the dry film developing step in the SAP method.

The adhesion of the plated circuit and the etching property for electroless copper plating are inherently difficult to be achieved, but according to the present invention, it is not surprisingBoth are expected to be possible. That is, as described above, the surface profile of the recess having the tapered shape, which is suitable for improving the adhesion to the plating circuit, tends to lower the etching property of the electroless copper plating in the step (h) of fig. 2. That is, more etching is required to remove the portion of the electroless copper plating where the intermediate tapered recess of the complex-type uneven shape is embedded and to remove the residual copper. However, the roughened copper foil of the present invention can achieve such a reduction in etching amount and ensure excellent adhesion of the plated circuit. This is considered to be because the treated surface Spc of the surface-treated copper foil and the Spc of the transfer surface of the resin molded product were set to 55mm, respectively^-1As described above, the uneven shape with no intermediate thinning is provided.

That is, since the peak of the convex portion is sharp when Spc is large, the peak of the convex portion is sharp, that is, Spc becomes large in the processed surface which is not thinned as compared with the processed surface which is thinned as the middle. When Spc is large, the apex of the projection is sharp on the transfer surface of the resin replica to which the uneven shape of the processed surface is transferred. This is because the transfer surface in the case of the concave-convex shape with the intermediate thinning has its apex flattened, whereas the transfer surface in the case of the concave-convex shape without the intermediate thinning has its apex not flattened and has a certain curvature (i.e., sharp). As a result, Spc becomes larger on the transfer surface with no thinning than on the transfer surface with thinning. That is, it is considered that the Spc of the treated surface of the surface-treated copper foil and the Spc of the transfer surface of the resin molded product were increased to 55mm, respectively^-1As described above, the above problem due to the tapered shape is smoothly solved by the uneven shape with no taper in the middle. That is, it is considered that the intermediate non-tapered shape allows electroless copper plating to faithfully follow the uneven shape of the treated surface and reproduce the same without impairing the shape thereof, and as a result, excellent adhesion to a plating circuit can be achieved without impairing the etching property for electroless copper plating. Thus, the adhesiveness of the plated circuit and the etching property against electroless copper plating can be both satisfied. Further, it is considered that by making such excellent adhesion and excellent etching property against electroless copper plating compatible, extremely fine dry film resolution can be achieved in the dry film developing step in the SAP method. Therefore, the temperature of the molten metal is controlled,the surface-treated copper foil of the present invention is preferably used for the production of a printed circuit board by the SAP method. In other words, the surface-treated copper foil of the present invention is preferably used for transferring a concave-convex shape to an insulating resin layer for a printed wiring board.

The surface-treated copper foil of the present invention has a treated surface on at least one side. The treated surface is a surface subjected to an arbitrary surface treatment, and is typically a roughened surface. In short, the surface-treated copper foil may have a treated surface (e.g., a roughened surface) on both sides or may have a treated surface on only one side. When both sides have treated surfaces, the surface on the laser irradiation side (the surface opposite to the surface in close contact with the insulating resin) is also surface-treated when used in the SAP method, and therefore the laser light absorption property is high, and as a result, the laser punching property is also improved.

The arithmetic mean curvature Spc of the peak top of the treated surface of the surface-treated copper foil of the present invention was 55mm^-1Above, preferably 60mm^-1Above and 200mm^-1Less, more preferably 60mm^-1Above and 150mm^-1The following. When the amount is within such a range, a concave-convex shape with no intermediate thickness can be easily obtained.

In the surface-treated copper foil of the present invention, when the resin film is thermally pressed against the treated surface to transfer the surface shape of the treated surface to the surface of the resin film and the surface-treated copper foil is removed by etching, the arithmetic mean curvature Spc of the peak top of the surface of the remaining resin film (i.e., the transfer surface of the resin replica) is 55mm^-1Above, preferably 60mm^-1Above and 200mm^-1Less, more preferably 60mm^-1Above and 150mm^-1Preferably 60mm or less^-1Above and 130mm^-1The following. When the amount is within such a range, a concave-convex shape with no intermediate thickness can be easily obtained. The resin film is preferably a thermosetting resin film, and may be in the form of a prepreg. Examples of the thermosetting resin include epoxy resin, cyanate resin, bismaleimide triazine resin (BT resin), polyphenylene ether resin, phenol resin, polyimide resin, and the like. Thermocompression bonding is sufficient if the uneven shape of the treated surface of the surface-treated copper foil can be transferred to the resin sheetThe film may be formed under any conditions, and is not particularly limited. For example, it is preferable to perform thermocompression bonding at a pressure of 3.0 to 5.0MPa and a temperature of 200 to 240 ℃ for 60 to 120 minutes.

The surface-treated copper foil of the present invention has a load area ratio Smr1 of preferably 9.0% or more, more preferably 10 to 20%, and still more preferably 10 to 15%, between the separated projected peaks and the central portion of the surface of the resin film remaining after etching (i.e., the transfer surface of the resin molded product). When the amount is within such a range, the shape without being tapered in the middle can be more desirably defined. As described above, the larger the value of Smr1, the larger the proportion of the projecting peaks. In this regard, since the thinned-out portion of the transfer surface of the resin replica is not detected by observation from above with a laser microscope, the equivalent of a rectangular virtual transfer surface having a rectangular recess with no thinned-out middle, which can be recognized by the laser microscope, is recognized by the laser microscope. As a result, the rate of increase in the cross-sectional area immediately after cutting into a circular piece from above became constant, i.e., the projected peak became small, and as a result, Smr1 became small. In contrast, the transfer surface that is not thinned in the middle has larger projecting crests than the transfer surface that is thinned in the middle (which is equivalent to the aforementioned rectangular virtual transfer surface), and therefore Smr1 becomes large. That is, the ratio of the projecting crests becomes larger in the non-tapered processed surface than in the tapered processed surface, that is, Smr1 becomes larger.

According to a preferred embodiment of the present invention, a plurality of roughening particles are adhered to the treatment surface. That is, the treated surface is preferably a roughened surface. The roughening particles are preferably formed of copper particles. The copper particles may be formed of metallic copper or a copper alloy. However, when the copper particles are a copper alloy, the solubility in the copper etching solution may be lowered, or the life of the etching solution may be reduced due to the mixing of an alloy component into the copper etching solution.

The peak density Spd of the treated surface, measured in accordance with ISO25178, is preferably 5000mm^-2Above and 20000mm^-2Hereinafter, more preferably 7000mm^-2Above 18000mm^-2Preferably 10000mm or less^-2The aboveAnd 15000mm^-2The following. When the amount is within the above range, the anchoring effect by the concave-convex shape can be sufficiently exhibited, and the adhesion of the plated circuit and the resolution of the dry film can be improved.

The thickness of the surface-treated 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, particularly preferably 0.5 to 5 μm, and most preferably 0.5 to 3 μm. The surface-treated copper foil of the present invention is not limited to the one obtained by subjecting the surface of a normal copper foil to a surface treatment such as roughening treatment, and may be one obtained by subjecting the surface of a copper foil with a carrier to a surface treatment such as roughening treatment.

Method for producing surface-treated copper foil

The surface-treated copper foil of the present invention can be produced by any method as long as the surface profile of the surface-treated copper foil of the present invention can be achieved.

(1) Preparation of copper foil

As the copper foil used for the production of the surface-treated copper foil, both an electrolytic copper foil and a rolled copper foil can be used. 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, further preferably 0.5 to 7 μm, particularly preferably 0.5 to 5 μm, and most preferably 0.5 to 3 μm. When the copper foil is prepared in the form of a copper foil with a carrier, the copper foil can be formed by a wet film forming method such as an electroless copper plating method or an electrolytic copper plating method, a dry film forming method such as sputtering or chemical vapor deposition, or a combination thereof.

(2) Surface treatment (roughening treatment)

At least one surface of the copper foil is roughened using copper particles. The roughening is carried out by electrolysis using a copper electrolytic solution for roughening treatment. The electrolysis is preferably carried out through a 2-stage plating process. In the plating step of stage 1, a copper sulfate solution containing copper at a concentration of 8 to 12g/L and sulfuric acid at a concentration of 200 to 280g/L is preferably used, and the plating temperature is 20 to 40 ℃ and the current density is 15 to 35A/dm²Plating conditions for 5 to 25 secondsElectrodeposition is performed. The plating step in stage 1 is preferably performed 2 times in total using 2 cells. In the plating step of stage 2, it is preferable to use a copper sulfate solution containing 65 to 80g/L copper and 200 to 280g/L sulfuric acid at a liquid temperature of 45 to 55 ℃ and a current density of 5 to 30A/dm²And carrying out electrodeposition under the plating condition for 5-25 seconds. The electric quantity in each stage is preferably the electric quantity Q in the plating step in stage 1₁Relative to the electric quantity Q in the plating process of the 2 nd stage₂Ratio of (Q)₁/Q₂) The content is less than 1.0, preferably 0.5 to 0.9, and more preferably 0.7 to 0.9. Thus by lowering Q₁/Q₂A roughened surface having a concavo-convex shape without intermediate thinning can be realized. The electric quantity Q at the time when the plating step at stage 1 was carried out a plurality of times₁Is the total electric quantity of a plurality of working procedures.

(3) Anti-rust treatment

If desired, the copper foil after the roughening treatment may be subjected to rust prevention treatment. The rust-preventive treatment preferably includes plating treatment using zinc. The plating treatment using zinc may be any of a zinc plating treatment and a zinc alloy plating treatment; among the zinc alloy plating treatments, a zinc-nickel alloy treatment is particularly preferable. The zinc-nickel alloy treatment may contain other elements such as Sn, Cr, and Co as long as it is a plating treatment containing at least Ni and Zn. The Ni/Zn adhesion ratio in the zinc-nickel alloy plating is preferably 1.2 to 10, more preferably 2 to 7, and further preferably 2.7 to 4 in terms of mass ratio. The rust-preventive treatment preferably further includes chromate treatment, and the chromate treatment is more preferably performed on the surface of the plating layer including zinc after the plating treatment using zinc. Thus, the rust prevention property can be further improved. A particularly preferred rust inhibiting 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. This improves moisture resistance, chemical resistance, adhesion to adhesives and the like. The silane coupling agent layer can be formed by appropriately diluting the silane coupling agent, applying the diluted silane coupling agent layer, and drying the silane coupling agent layer. Examples of the silane coupling agent include: epoxy-functional silane coupling agents such as 4-glycidylbutyltrimethoxysilane and 3-glycidoxypropyltrimethoxysilane; or amino-functional silane coupling agents such as 3-aminopropyltriethoxysilane, N-2 (aminoethyl) 3-aminopropyltrimethoxysilane, N-3- (4- (3-aminopropoxy) butoxy) propyl-3-aminopropyltrimethoxysilane and N-phenyl-3-aminopropyltrimethoxysilane; or mercapto-functional silane coupling agents such as 3-mercaptopropyltrimethoxysilane, or olefin-functional silane coupling agents such as vinyltrimethoxysilane and vinylphenyltrimethoxysilane; or an acrylic functional silane coupling agent such as 3-methacryloxypropyltrimethoxysilane; or imidazole-functional silane coupling agents such as imidazole silane; and triazine functional silane coupling agents such as triazine silane.

Copper foil with carrier

The surface-treated copper foil of the present invention may be provided in the form of a copper foil with a carrier. In this case, the copper foil with carrier includes: a carrier; a peeling layer provided on the carrier; and a surface-treated copper foil of the present invention provided on the release layer with a treated surface (typically, a roughened surface) as an outer side. Of course, the copper foil with a carrier may be formed of a known layer, other than the surface-treated copper foil of the present invention.

The carrier is a layer (typically a foil) for supporting the rough-surface-treated copper foil to improve its handling. Examples of the carrier include an aluminum foil, a copper foil, and a resin film having a surface coated with a metal, and the copper foil is preferable. The copper foil may be any of a rolled copper foil and an electrolytic copper foil. The thickness of the support is typically 200 μm or less, preferably 12 to 35 μm.

The surface of the carrier on the release layer side preferably has a ten-point surface roughness Rzjis of 0.5 to 1.5 μm, more preferably 0.6 to 1.0 μm. Rzjis may be measured according to JIS B0601: 2001, respectively. By providing such a ten-point surface roughness Rzjis in advance to the release layer side surface of the carrier, it is possible to easily impart an ideal surface profile to the surface-treated copper foil of the present invention produced via the release layer thereon.

The release layer has a function of weakening the peel strength of the carrier, ensuring the stability of the strength, and further suppressing interdiffusion that can occur between the carrier and the copper foil during press forming at high temperature. The release layer is usually formed on one surface of the carrier, but may be formed on both surfaces. The release layer may be any of an organic release layer and an inorganic release layer. Examples of the organic component used in the organic release layer include: nitrogen-containing organic compounds, sulfur-containing organic compounds, carboxylic acids, and the like. Examples of the nitrogen-containing organic compound include: a triazole compound, an imidazole compound, and the like, and among them, a triazole compound is preferable in that the releasability is easily stabilized. Examples of triazole compounds include: 1,2, 3-benzotriazole, carboxybenzotriazole, N' -bis (benzotriazolylmethyl) urea, 1H-1,2, 4-triazole and 3-amino-1H-1, 2, 4-triazole. Examples of sulfur-containing organic compounds include: mercaptobenzothiazole, thiocyanuric acid, 2-benzimidazole thiol, and the like. Examples of the carboxylic acid include monocarboxylic acid and dicarboxylic acid. On the other hand, examples of the inorganic component used in the inorganic release layer include: ni, Mo, Co, Cr, Fe, Ti, W, P, Zn, chromate film, etc. The release layer may be formed by contacting at least one surface of the carrier with a solution containing a release layer component to fix the release layer component to the surface of the carrier. The contact between the carrier and 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, or flowing down of the release layer component-containing solution. The fixation of the release layer component to the surface of the support may be performed by adsorption and drying of a solution containing the release layer component, electrodeposition of the release layer component in the solution containing the release layer component, or the like. The thickness of the release layer is typically 1nm to 1 μm, preferably 5nm to 500 nm.

The surface-treated copper foil of the present invention is used as a surface-treated copper foil. The surface-treated copper foil of the present invention is typically a surface-treated copper foil subjected to roughening treatment using copper particles, and as a step, a copper layer is first formed as a copper foil on the surface of the release layer, and then at least roughening is performed. Details regarding roughening are as previously described. The copper foil is preferably formed as an extra thin copper foil, taking advantage of the advantages of the copper foil with carrier. The thickness of the extra thin copper foil is preferably 0.1 to 7 μm, more preferably 0.5 to 5 μm, and still more preferably 0.5 to 3 μm.

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

Copper-clad laminated board

The surface-treated copper foil or copper foil with a carrier of the present invention is preferably used for producing a copper-clad laminate for a printed wiring board. That is, according to a preferred embodiment of the present invention, there is provided a method for producing a copper-clad laminate, characterized by producing a copper-clad laminate using the surface-treated copper foil or the copper foil with a carrier, or providing a copper-clad laminate obtained using the surface-treated copper foil or the copper foil with a carrier. By using the surface-treated copper foil or copper foil with carrier of the present invention, a copper-clad laminate particularly suitable for the SAP method can be provided. The copper-clad laminate comprises: the copper foil with a carrier of the present invention includes a resin layer provided in close contact with the treated surface. The copper foil with carrier may be provided on one side or both sides of the resin layer. The resin layer contains a resin, preferably an insulating resin. The resin layer is preferably a prepreg and/or a resin sheet. The prepreg is a generic name of a composite material obtained by impregnating a synthetic resin into a base material such as a synthetic resin plate, a glass woven fabric, a glass nonwoven fabric, or paper. Preferred examples of the insulating resin include: epoxy resins, cyanate ester resins, bismaleimide triazine resins (BT resins), polyphenylene ether resins, phenol resins, and the like. Examples of the insulating resin constituting the resin sheet include: and insulating resins such as epoxy resins, polyimide resins, and polyester resins. In addition, the resin layer may contain filler particles containing various inorganic particles such as silica and alumina, from the viewpoint of improving insulation properties. The thickness of the resin layer is not particularly limited, but is preferably 1 to 1000. mu.m, more preferably 2 to 400. mu.m, and still more preferably 3 to 200. mu.m. The resin layer may be composed of a plurality of layers. The resin layer such as a prepreg and/or a resin sheet may be provided on the copper foil with carrier via a primer resin layer applied in advance to the surface of the copper foil.

Printed circuit board

The surface-treated copper foil or copper foil with carrier of the present invention is preferably used for the production of printed wiring boards, and particularly preferably used for the production of printed wiring boards by the SAP method. That is, according to a preferred embodiment of the present invention, there is provided a method for manufacturing a printed wiring board, characterized by manufacturing a printed wiring board using the surface-treated copper foil or the copper foil with a carrier, or providing a printed wiring board obtained using the surface-treated copper foil or the copper foil with a carrier. By using the surface-treated copper foil or copper foil with a carrier of the present invention, it is possible to provide a surface-treated copper foil which can impart a surface profile excellent not only in adhesion to a plated circuit but also in etching properties for electroless copper plating to a laminate in the production of a printed wiring board. In addition, by using the surface-treated copper foil, an extremely fine dry film resolution can be achieved in the dry film developing step in the SAP method. Therefore, a printed wiring board in which extremely fine circuits are formed can be provided. The printed wiring board of the present embodiment includes a layer in which a resin layer and a copper layer are sequentially stacked. In the case of the SAP method, since the surface-treated copper foil of the present invention is removed in the step (c) of fig. 1, the printed circuit board manufactured by the SAP method does not include the surface-treated copper foil of the present invention, but only the surface profile transferred from the treated surface of the surface-treated copper foil remains. In addition, as for the resin layer, as described above with respect to the copper-clad laminate. In any case, the printed circuit board may be constructed using known layers. Specific examples of the printed wiring board include: a single-sided or double-sided printed wiring board obtained by bonding the surface-treated copper foil of the present invention to one side or both sides of a prepreg and curing the same to form a laminate, and then forming a circuit; multilayer printed wiring boards obtained by multilayering these components, and the like. Further, as other specific examples, a flexible printed wiring board, COF, TAB tape, and the like, in which a surface-treated copper foil of the present invention is formed on a resin film to form a circuit, may be cited. Further, as other specific examples, there may be mentioned: a laminated wiring board in which a resin-attached copper foil (RCC) is formed by applying the resin layer to the surface-treated copper foil of the present invention, the printed circuit board is laminated with the resin layer as an insulating adhesive layer, and then a circuit is formed by a method such as an MSAP method or a subtractive method using the surface-treated copper foil as all or a part of a wiring layer, or a laminated wiring board in which a circuit is formed by an SAP method by removing the surface-treated copper foil; a direct build-up wafer (direct build on wafer) or the like in which a copper foil with resin is laminated and a circuit is formed is alternately repeated on a semiconductor integrated circuit. Specific examples of further developments include: an antenna element obtained by laminating the resin-attached copper foil on a base material and forming a circuit; an electronic material for panel/display and an electronic material for window glass, which are laminated on glass or a resin film via an adhesive layer and have a pattern formed thereon; an electromagnetic wave shield/film formed by coating a conductive adhesive on the surface-treated copper foil of the present invention. The copper foil with carrier of the present invention is particularly suitable for the SAP method. For example, when the circuit is formed by the SAP method, the configuration shown in fig. 1 and 2 can be adopted.

[ examples ]

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

Examples 1 and 2

As the surface-treated copper foil with carrier, a roughened copper foil with carrier was produced and evaluated as follows.

(1) Production of the Carrier

As the copper electrolytic solution, a copper sulfate solution having the following composition was used; as the cathode, a titanium rotary electrode having an arithmetic average surface roughness Ra (according to JIS B0601: 2001) of 0.20 μm was used; the anode was DSA (dimensionally stable anode) at a solution temperature of 45 ℃ and a current density of 55A/dm²Then, electrolysis was carried out to obtain an electrolytic copper foil having a thickness of 12 μm as a carrierAnd (3) a body. According to JIS B0601: 2001 the ten-point average roughness Rzjis of the release layer side surface of the obtained carrier was measured, and found to be 0.9 μm.

< composition of copper sulfate solution >

-copper concentration: 80g/L

-sulfuric acid concentration: 260g/L

-bis (3-sulfopropyl) disulfide concentration: 30mg/L

-diallyl dimethyl ammonium chloride polymer concentration: 50mg/L

-chlorine concentration: 40mg/L

(2) Formation of a Release layer

The electrode surface side of the copper foil for carrier subjected to acid washing was immersed in a CBTA aqueous solution having a CBTA (carboxybenzotriazole) concentration of 1g/L, a sulfuric acid concentration of 150g/L and a copper concentration of 10g/L at a liquid temperature of 30 ℃ for 30 seconds to adsorb the CBTA component to the electrode surface of the carrier. 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 with the organic release layer formed thereon was immersed in a solution of nickel sulfate having a nickel concentration of 20g/L at a liquid temperature of 45 ℃, a pH of 3 and a current density of 5A/dm²Nickel was attached to the organic release layer in an amount corresponding to 0.001 μm thick. Thus, a nickel layer was formed on the organic peeling layer as an auxiliary metal layer.

(4) Formation of ultra-thin copper foil

Immersing a carrier copper foil having an auxiliary metal layer formed thereon in a copper sulfate solution having a composition shown below, at a solution temperature of 50 ℃ and a current density of 5 to 30A/dm²Next, electrolysis was performed to form an extra thin copper foil having a thickness of 3 μm (examples 1, 3 and 4) or 2.5 μm (example 2) on the auxiliary metal layer.

< composition of solution >

-copper concentration: 60g/L

-sulfuric acid concentration: 200g/L

(5) Roughening treatment

The deposited surface of the extra thin copper foil is subjected to roughening treatment. The roughened partThe plating was performed by the following 2-stage plating. The plating step in stage 1 was carried out 2 times in total using 2 baths, and in each plating step (i.e., each bath), a copper sulfate solution containing 10.8g/L copper and 230 to 250g/L sulfuric acid was used at a solution temperature of 25 ℃ and a current density of 25A/dm²The electrodeposition is performed under the plating conditions of (1). In the plating step of stage 2, a copper sulfate solution containing 70g/L copper and 230 to 250g/L sulfuric acid is used at a solution temperature of 50 ℃ and a current density of 58A/dm²The electrodeposition is performed under the plating conditions of (1). The electric quantity of each stage is equal to the electric quantity Q in the plating process of the 1 st stage₁Relative to the electric quantity Q in the plating process of the 2 nd stage₂Ratio of (Q)₁/Q₂) Less than 1 (specifically, 0.87). Specifically, electrodeposition was performed under each condition shown in table 1.

(6) Anti-rust treatment

The roughened copper foil with carrier is subjected to rust-preventive treatment including inorganic rust-preventive treatment and chromate treatment on both surfaces thereof. First, as an inorganic rust-preventive treatment, a pyrophosphate bath was used, and the concentration of potassium pyrophosphate was 80g/L, the concentration of zinc was 0.2g/L, the concentration of nickel was 2g/L, the liquid temperature was 40 ℃ and the current density was 0.5A/dm²Then, zinc-nickel alloy rust-proof treatment is carried out. Next, as chromate treatment, a chromate layer is further formed in addition to the rust prevention treatment of the zinc-nickel alloy. The chromate treatment is carried out at a chromic acid concentration of 1g/L, pH11, a solution temperature of 25 ℃ and a current density of 1A/dm²The process is carried out as follows.

(7) Silane coupling agent treatment

The copper foil subjected to the rust-preventive treatment is washed with water and immediately treated with a silane coupling agent so that the silane coupling agent is adsorbed on the rust-preventive treatment layer on the roughened surface. The silane coupling agent treatment was performed as follows: the adsorption treatment was performed by spraying a solution of 3 g/L3-aminopropyltrimethoxysilane using pure water as a solvent onto the surface to be roughened. After the adsorption of the silane coupling agent, water was evaporated by a final electric heater to obtain a copper foil with carrier having a roughened copper foil with a thickness of 3 μm (examples 1, 3 and 4) or 2.5 μm (example 2).

(8) Evaluation of roughened copper foil

The obtained roughened copper foil was evaluated for various properties of the surface profile including the roughened particles as follows.

< Spc and Spd of roughened copper foil >

The area of the roughened surface of the roughened copper foil was 100 μm by a laser method using a laser microscope (VK-X100, manufactured by KEYENCE CORPORATION)²The surface profile of the two-dimensional region (10 μm × 10 μm) of (4) was analyzed, and the arithmetic mean curvature Spc (mm) of the peak top of the roughened surface of the roughened copper foil was determined in accordance with ISO25178^-1) Peak density of sum peaks Spd (mm)^-2) And (4) carrying out measurement. The measurement was performed with the cutoff wavelength obtained by the S filter set to 0.8 μm and the cutoff wavelength obtained by the L filter set to 0.1 μm. The above measurements were performed 3 times in total on the same sample, and the average value of these measurements was used as the measurement value.

< Spc and Smr1 on the surface of resin molded article >

A replica shape of the surface contour of the roughened surface of the roughened copper foil is formed with a resin, and the surface contour of the surface of the obtained resin replica is analyzed. Specifically, first, a prepreg (manufactured by Mitsubishi gas chemical Co., Ltd., GHPL-830NS, thickness 0.1mm) was laminated in contact with the extra thin copper foil side of the copper foil with a carrier, and thermocompression bonded at a pressure of 4.0MPa and a temperature of 220 ℃ for 90 minutes. Thereafter, the carrier was peeled off, and the extra thin copper foil pressed and bonded was completely removed with a copper chloride-based etching solution to obtain a resin composite product to which the surface profile of the roughened surface was transferred. The transfer surface (surface to which the surface profile of the roughened surface was transferred) of the resin composite product was applied with a laser method using a laser microscope (VK-X100, manufactured by KEYENCECORPORATION) to an area of 100 μm²The surface profile of the two-dimensional region (10 μm × 10 μm) of (A) was analyzed, and the arithmetic mean curvature Spc (mm) of the peak top of the resin replica surface was determined in accordance with ISO25178^-1) And the load area ratio Smr1 (%) separating the projected ridge from the central portion. The measurement was performed with the cutoff wavelength obtained by the S filter set to 0.8 μm and the cutoff wavelength obtained by the L filter set to 0.1 μm.The above measurements were performed 3 times in total on the same sample, and the average value of these measurements was used as the measurement value.

(9) Production of copper-clad laminated board

A copper-clad laminate is produced using a copper foil with a carrier. First, an extra thin copper foil with a carrier copper foil was laminated on the surface of an inner layer substrate via a prepreg (manufactured by Mitsubishi gas chemical Co., Ltd., GHPL-830NSF, thickness 0.1mm), thermocompression bonded at a pressure of 4.0MPa and a temperature of 220 ℃ for 90 minutes, and then the carrier was peeled off to produce a copper-clad laminate.

(10) Preparation of laminate for SAP evaluation

Next, after removing the entire copper foil on the surface with a sulfuric acid/hydrogen peroxide etching solution, degreasing, applying a Pd-based catalyst, and activating treatment were performed. The surface thus activated was subjected to electroless copper plating (thickness: 1 μm) to obtain a laminate just before the dry film was attached in the SAP method (hereinafter referred to as a laminate for SAP evaluation). These steps are performed according to the known conditions of the SAP method.

(11) Evaluation of laminate for SAP evaluation

The obtained laminate for SAP evaluation was evaluated for various properties as follows.

< adhesion (peel strength) of plated Circuit >

The dry film was attached to the laminate for SAP evaluation, and exposure and development were performed. After depositing a copper layer having a thickness of 19 μm on the developed laminate masked with the dry film by pattern plating, the dry film was peeled off. The electroless copper plating exposed on the surface was removed with a sulfuric acid/hydrogen peroxide etching solution to prepare a peel strength measurement sample having a height of 20 μm and a width of 10 mm. The peel strength when the copper foil was peeled from the evaluation sample was measured according to JIS C6481 (1996).

< etching Property >

The laminate for SAP evaluation was etched 0.2 μm each time with a sulfuric acid/hydrogen peroxide etching solution, and the amount (depth) until copper on the surface completely disappeared was measured. For the measurement method, confirmation was performed with an optical microscope (500-fold). More specifically, the operation of confirming the presence or absence of copper by an optical microscope every time 0.2 μm etching was performed was repeated, and a value (μm) obtained by (the number of times of etching) × 0.2 μm was used as an index of the etching property. For example, an etching property of 1.2 μm means that when 6 times of etching of 0.2 μm is performed, residual copper is not detected by an optical microscope (that is, 0.2 μm × 6 times 1.2 μm). That is, the smaller the value, the more the copper on the surface can be removed by etching a smaller number of times. Namely, the method comprises the following steps: the smaller the value, the better the etching property.

< Dry film resolution (minimum L/S) >

A dry film having a thickness of 25 μm was attached to the surface of the laminate for SAP evaluation, and exposure and development were carried out using a mask having a pattern with a line/space (L/S) of 2 μm/2 μm to 15 μm/15 μm. The exposure amount at this time was 125 mJ. The surface of the developed sample was observed with an optical microscope (500 times), and the smallest (i.e., finest) L/S among L/S at which development could be performed without problems was used as an index of dry film resolution. For example, the minimum L/S of 10 μm/10 μm, which is an index for evaluating the resolution of the dry film, means that the dry film can be resolved without any problem from L/S of 15 μm/15 μm to 10 μm/10 μm. For example, when resolution is possible without any problem, a sharp contrast is observed between dry film patterns, whereas when resolution is not satisfactory, a sharp contrast is not observed in a portion where black is observed between dry film patterns.

Example 3(comparison)

In the roughening treatment, the electric quantity Q in the plating process of the 1 st stage₁Relative to the electric quantity Q in the plating process of the 2 nd stage₂Ratio of (Q)₁/Q₂) A roughened copper foil with a carrier was produced and evaluated in the same manner as in example 1 except that the method was set to 2.16 (specifically, electrodeposition was performed under the conditions shown in table 1).

Example 4(comparison)

In the roughening treatment, the electric quantity Q in the plating process of the 1 st stage₁Relative to the electric quantity Q in the plating process of the 2 nd stage₂Ratio of (Q)₁/Q₂) Tape loading was performed in the same manner as in example 1 except that the setting was made to 3.38 (specifically, electrodeposition was performed under the conditions shown in table 1), andproduction and evaluation of bulk-roughened copper foil.

Results

The evaluation results obtained in examples 1 to 4 are shown in Table 2.

[ Table 1]

[ Table 2]

Claims

1. A surface-treated copper foil having a treated surface on at least one side,

the arithmetic mean curvature Spc of the peak apex of the treated surface, determined in accordance with ISO25178, is 55mm^-1In the above-mentioned manner,

when a resin film is heat-pressure bonded to the treated surface to transfer the surface shape of the treated surface to the surface of the resin film and the surface-treated copper foil is removed by etching, the arithmetic mean curvature Spc of the peak top of the surface of the resin film remaining is 55mm as measured in accordance with ISO25178^-1In the above-mentioned manner,

the peak density Spd of the treated surface measured according to ISO25178 is 5000mm^-2Above and 20000mm^-2The following.

2. The surface-treated copper foil according to claim 1, wherein a load area ratio Smr1 of the surface of the resin film remaining after the etching, which is measured in accordance with ISO25178, for separating a projected peak from a central portion is 9.0% or more.

3. The surface-treated copper foil according to claim 1, wherein roughening particles are adhered to the treated surface.

4. The surface-treated copper foil according to claim 1, wherein the surface-treated copper foil has a thickness of 0.5 to 5 μm.

5. The surface-treated copper foil according to claim 1, which is used for transferring a concavo-convex shape to an insulating resin layer for a printed wiring board.

6. The surface-treated copper foil according to claim 1, which is used for the production of a printed circuit board based on a semi-additive method.

7. A copper foil with carrier, comprising:

a carrier;

a peeling layer provided on the carrier; and the number of the first and second groups,

the surface-treated copper foil according to any one of claims 1 to 6 provided on the release layer with the treated surface as an outer side.

8. A method for producing a copper-clad laminate, characterized in that the surface-treated copper foil according to any one of claims 1 to 6 is used to produce a copper-clad laminate.

9. A method for producing a copper-clad laminate, characterized in that the copper foil with a carrier according to claim 7 is used to produce a copper-clad laminate.

10. A method for manufacturing a printed wiring board, characterized in that the surface-treated copper foil according to any one of claims 1 to 6 is used to manufacture a printed wiring board.

11. A method for manufacturing a printed wiring board, characterized in that the copper foil with a carrier of claim 7 is used to manufacture a printed wiring board.