WO2010093009A1 - Metal foil, method for producing same, insulating substrate, and wiring board - Google Patents

Abstract

Disclosed is a surface-treated metal foil which can be produced at low cost and enables easy formation of an extremely thin electroless plated copper foil, which does not require a sputtering process for forming a fine circuit and is capable of maintaining high adhesion strength, on a substrate surface.  The surface-treated metal foil can provide a replica having a uniform roughening shape with an anchoring effect. Specifically disclosed is a surface-treated metal foil, wherein a roughening bump plating is formed on at least one surface of an untreated metal foil using a burnt plating, and the roughening bump plating is subjected to capsule plating.  The surface-treated metal foil has a surface roughness (Rz) of 1.0-2.5 μm.  The roughening bumps formed in the roughening bump plating have a columnar shape with an interval of not less than 0.1 μm but not more than 1.0 μm between adjacent roughening bumps.  The surface-treated metal foil is most suited for the use as a replica.  The surface-treated metal foil is preferably a copper foil.

Description

Metal foil and manufacturing method thereof, insulating substrate, wiring substrate

The present invention relates to a metal foil and a manufacturing method thereof. In particular, the present invention relates to a replica metal foil for forming a wiring with a thin film conductor layer on an insulating substrate, and a method for manufacturing the same.
The metal foil for replica is particularly suitable for manufacturing a wiring board for mounting a semiconductor element, an integrated circuit, an electronic component and the like.
The present invention also relates to an insulating substrate having a roughened surface formed using a metal foil, and a wiring substrate having a predetermined wiring pattern formed on the roughened surface of the insulating substrate.

Due to recent advances in electronic technology, wiring boards for mounting semiconductor elements, integrated circuits, electronic components, etc. are rapidly becoming more integrated, higher output, and faster in addition to being lighter, thinner and smaller. Therefore, for example, when forming a metal wiring such as copper on a semiconductor substrate, it is common to use sputtering film formation and electrolytic plating in combination. In particular, in semiconductor devices, process development for miniaturization of copper wiring is rapidly progressing with higher functions and higher speeds. Due to the high integration of wiring boards as described above, the reduction in wiring width and the increase in wiring length are inevitably required for lighter and thinner devices. For example, the electrical resistance of wiring materials causes signal delays, which hinders the increase in transmission speed. To do. For this reason, an ultrathin metal material having a small electric resistance is used as the wiring material.

As a conventional technology for forming an ultrathin metal film on a wiring board, a sputtering method and a CVD (chemical vapor deposition) method have been employed. Among them, a sputtering method that is advantageous from the viewpoint of mass productivity and stability of film formation is generally employed. However, the wiring formed by the sputtering method has a problem that a disconnection accident easily occurs due to stress migration generated by electromigration or expansion / contraction of the wiring, and there is a problem in that the manufacturing yield of the wiring substrate is lowered. Furthermore, it is necessary to use special processing equipment, and the manufacturing cost is high, so that improvement in cost performance has been an issue.

The present invention provides a metal foil suitable for use in a so-called replica method in which a surface shape of a metal foil surface is transferred to an insulating substrate and a thin metal layer is formed on the transferred surface in the production of a wiring board. .

Here, the usage method (replica method) in which the metal foil is used for a replica will be described first. In order to simplify the description, a process of forming a metal foil replica on one surface of the wiring board will be described.

A wiring board for mounting semiconductor elements, integrated circuits, electronic components, etc. is an insulating substrate such as an epoxy resin or semi-cured resin coated imide resin, liquid crystal polymer resin film, etc. . In addition, this wiring board is made by impregnating an insulating fiber such as an aramid resin or glass with an epoxy resin, and further, for example, an epoxy layer semi-cured state having a thickness of about 5 to 20 μm, that is, an insulating material such as a glass epoxy board formed by a B stage It is a substrate.

A metal foil is laminated on this insulating substrate. For example, a copper foil having a roughened surface is employed as the metal foil. The roughened surface side of the metal foil is laminated on the surface of the insulating substrate by vacuum hot pressing.
Next, the laminated metal foil is removed by etching. The surface of the insulating substrate is vacuum-heat-pressed metal foil and the metal on the roughened surface of the metal foil that has penetrated into the insulating substrate. For example, when the metal foil is a copper foil, it is generally used for the production of wiring boards. Etch away with an etchant such as iron chloride or copper chloride.

The metal on the roughened surface is removed from the surface of the insulating substrate by etching away the metal foil. For this reason, the uneven | corrugated shape of the roughening process surface of metal foil is transcribe | transferred to an insulating substrate, and the roughening process surface by an unevenness | corrugation (replica) is formed in the insulating substrate surface. If the roughened surface of the metal foil is granular, the uneven shape transferred to the surface of the insulating substrate is a concave portion having many granular shapes. The concave portion is formed not only with a large surface area but also with a shape in which there is a portion where the cross sectional area of the opening inside the concave portion is larger than the size of the cross sectional area of the opening on the concave surface. Therefore, the concave portion has an optimum shape for the anchor effect.

Next, palladium serving as the core of electroless plating is attached to the surface of the insulating substrate, and then a metal having a low electrical resistivity, for example, copper is thinly plated to a thickness of about 0.1 to 5 μm by electroless plating.
Next, a plating mask is provided in a region other than the desired wiring pattern on the surface of the thinly plated plating layer. The plating mask is formed, for example, by providing a photosensitive resin on the surface of the plating layer, and then exposing and developing with a light mask for forming a desired pattern.

Thereafter, by supplying power from the electroless plating layer formed as described above, a wiring is formed by electroplating a highly conductive metal, for example, copper, in a desired wiring pattern region where the photosensitive resin is not deposited.

Next, after removing the photosensitive resin, etching is performed with an etching solution such as a hydrogen peroxide sulfate, a persulfate, or an ammonia complex, and the electroless plating layer that is not covered with the electroplating layer is removed. Since the electroless plating layer is thinner than the wiring of the electroplating metal layer, the etching rate is high. And the wiring of the electroplating layer of a desired pattern is hardly etched. For this reason, the electroless plating layer under the desired pattern by the electroplating layer is not etched because the wiring of the electroplating layer is protected using the mask. Finally, it is immersed in a mixed solution of potassium permanganate and sodium hydroxide. This removes the palladium that was deposited on the exposed surface of the insulating substrate and could not be etched with the etchant. (This method is disclosed in, for example, Patent Document 1.)

JP 2006-196813 A

In Patent Document 1, the roughened surface of the copper foil is plated on the surface of the copper foil by multiplying the current of electroplating several times as usual, that is, by utilizing an abnormal plating phenomenon (discoloration plating), The fine particles are grown by plating. In this document, the overall rough shape, such as the size, roughness, and granularity of the particles, is an important factor in the adhesion strength with the insulating substrate, and has been optimized by the copper foil manufacturer and is easily available. Although it is described as being, details thereof are not disclosed.

The present invention has been intensively studied on a replica metal foil suitable for manufacturing a wiring board for mounting a semiconductor element, an integrated circuit, an electronic component, etc., and a metal having a roughened surface having a preferable shape as a metal foil for replica use. By providing a foil, the present invention has succeeded in providing a wiring substrate having a wiring pattern that has excellent adhesion between the insulating substrate and the wiring pattern, and that has excellent etching straightness and thickness uniformity.

Conventionally, electrolytic copper foils on the market generally have a roughened shape for improving adhesion to the substrate, and the copper grains are generally closely attached at the roots.
The surface-treated metal foil mainly used for replicas according to the present invention is characterized in that fine columnar irregularities having a gap of 0.1 μm or more and 1.0 μm or less are formed on the roughened surface side.

The metal foil of the present invention is a metal foil having a roughened plating surface, and the roughened plating surface is subjected to roughening galvanization by burnt plating on at least one surface of the untreated metal foil. The surface roughness of the surface is Rz value defined in JIS-B-0601 (hereinafter the same) is 1.0 μm to 2.5 μm, and the roughened bump formed by the roughened bump plating is The columnar shape has a gap of 0.1 μm or more and 1.0 μm or less between adjacent roughing bumps.

The metal foil of the present invention is a metal foil in which the roughened plating surface is subjected to rust prevention treatment.

In the metal foil of the present invention, the untreated metal foil is a rolled copper foil or an electrolytic copper foil, and the surface roughness of at least the plated roughened surface forming side of the untreated copper foil is from 1.0 μm to 2. It is a metal foil which is 2 μm.

The main use of the metal foil of the present invention is replica use.

The insulating substrate of the present invention is an insulating substrate having a roughened surface formed by transferring the uneven shape on the roughened plating surface of the metal foil.

The wiring board of the present invention is a wiring board in which a predetermined wiring pattern is formed on the roughened surface of the insulating substrate.

The metal foil manufacturing method of the present invention is added to an untreated metal foil having a surface roughness Rz value of 1.0 μm to 2.2 μm to a sulfuric acid-copper sulfate plating solution, a pyrophosphate copper plating solution or a copper carbonate plating solution. Burn plating is performed in a plating bath to which a metal is added to form a roughened galvanized surface. Capsule plating is applied to the roughened galvanized surface, and the surface roughness is 1.0 to 2.5 μm in terms of Rz value. A roughened plated surface having a columnar shape with a gap of 0.1 μm or more and 1.0 μm or less between the surface and the surface of the surface.

In the metal foil manufacturing method of the present invention, the additive metal added to the plating solution is iron, chromium, molybdenum, tungsten, and / or vanadium and antimony.

In the method for producing a metal foil of the present invention, a rust prevention treatment is applied to the roughened plated surface.

In the metal foil manufacturing method of the present invention, the untreated metal foil is a rolled copper foil or an electrolytic copper foil.

The main use of the metal foil roughened by the metal foil manufacturing method of the present invention is a replica application.

Since the metal foil of the present invention is mainly excellent in the anchoring effect (anchor effect using the replica) in the replica application, it is possible to reduce the plating amount cost in the electroless plating which is a subsequent process. Moreover, since the metal foil of this invention is excellent in the adhesiveness of an insulated substrate and a wiring pattern, it is excellent in the etching straightness in the fine wire circuit etching process at the time of circuit manufacture. Therefore, the present invention has an excellent effect in the production of a wiring board for mounting a semiconductor element, an integrated circuit, an electronic component, and the like.

(A) is a photograph showing a standard (level) for judging the straightness of the circuit after etching. (B) is a photograph showing a reference (level) for determining residual copper mapping by EPMA (X-ray microanalyzer; Electron Probe Micro-Analysis). (C) is a photograph explaining the roughened bump gap.

The metal foil of the present invention may be a stainless steel foil, an aluminum foil, a copper foil or the like, and any metal foil that can be etched as a foil for replica use.
Hereinafter, the present invention will be described in detail by taking, as an example, an electrolytic copper foil that is expected to be highly demanded as a metal foil. In addition, since the same result is obtained also about rolled copper foil, detailed description is abbreviate | omitted.
The electrolytic copper foil before forming the roughened plating surface used in the present invention (hereinafter sometimes referred to as an untreated copper foil) has a unit thickness of 60 g / m ² to 153 g / m ² (nominal thickness of 9 to 18 μm). The crystal structure in the thickness direction is fine grains (fine crystals). “Unit weight” indicates a theoretical thickness obtained by dividing “unit weight (weight per unit area)” by “copper specific gravity (8.9)” (that is, “unit thickness” = “ Single weight "/" copper specific gravity (8.9) "). “Nominal thickness” indicates the actually measured thickness.
Single heavy Mi of untreated copper foil, in the range from 60 g / m ² of 153 g / m ^2, the untreated foils or roughened, handling properties at the time of laminating the roughening treatment foil on the insulating substrate Furthermore, it is because the characteristics such as the ease of the etching process when removing the foil by etching are excellent.

This untreated copper foil is burnt-plated. A metal additive is added to a basic plating solution composition of any one of a sulfuric acid-copper sulfate plating solution, a pyrophosphate copper plating solution, and a copper carbonate plating solution in a plating bath for performing burnt plating. As a metal additive, Fe (iron), Mo (molybdenum), Cr (chromium), W (tungsten), and V (vanadium) or Sb (antimony) or both are added.
The surface of the untreated copper foil is subjected to burnt plating in the vicinity of the limiting current density of the plating bath, thereby forming a bumpy columnar shape of fine crystals. A predetermined amount of Fe (iron), Mo (molybdenum), Cr (chromium), and W (tungsten) is added to the burnt plating bath as shown below, so that a plurality of fine columnar shapes provide gaps. Formed. Further, by adding V (vanadium) or Sb (antimony), chemical resistance can be improved when a single-side treated foil is formed. Details of the plating method will be described later.

Next, smooth plating, so-called capsule plating, is applied to roughen the surface of the roughened copper foil or replica so that the copper grains of the bumpy fine columnar shape on the surface of the roughened bumped surface formed by roughened bumped plating by burnt plating are not easily dropped. Copper foil (hereinafter, sometimes simply referred to as replica copper foil). The capsule plating method will be described later.
In the above capsule plating, the roughened surface of the finished roughened plating surface has an Rz value specified by JIS-B-0601 (hereinafter the same) of 1.0 μm or more and 2.5 μm or less, and the copper particles are capsule plated. Even after being applied, the fine columnar shape (columnar shape) is maintained, and the columnar gaps between the columnar shapes are 0.1 μm or more and 1.0 μm or less.

As described above, the replica copper foil manufactured as described above is first laminated on an insulating substrate to be laminated, for example, an epoxy base material, a polyimide resin, or an organic film. Thereafter, the replica copper foil is completely dissolved and removed by etching to form a fine columnar replica having columnar gaps on the surface of the insulating substrate. That is, the uneven shape on the roughened plating surface of the replica copper foil (metal foil) is transferred to form a roughened surface on the insulating substrate. Then, after forming a metal film by plating on the roughened surface of the insulating substrate, wet etching is performed on the metal film, pattern processing is performed, and a predetermined wiring pattern is formed, thereby forming a wiring substrate. To do.

Conventionally, commercially available single-side roughened copper foil, which is frequently used for replica applications, generally has a mortar-shaped concave portion on the surface, and the copper grain bumps are closely attached at the root. For this reason, the anchoring effect (anchor effect using a replica) is inferior, and the amount of plating during electroless plating increases, resulting in an increase in cost. Furthermore, the etching straightness in the fine line circuit etching process during the subsequent circuit fabrication is also poor.

The copper foil of the present invention, which is mainly used for replicas, has a fine columnar shape having a gap of 0.1 μm or more and 1.0 μm or less on the roughened surface side. For this reason, by using the copper foil, it is possible to easily form unevenness (replica) excellent in anchoring effect (anchor effect using a replica) with a uniform and concave spacing and shape on the surface of the insulating substrate. Can do. Therefore, the amount of plating during electroless plating, which is a subsequent process, can be saved to a minimum, and the straightness of etching in the fine line circuit etching process during subsequent circuit fabrication is excellent. Therefore, it is possible to provide a surface-treated copper foil having a roughened surface that is preferable as a replica copper foil suitable for manufacturing a wiring board for mounting a semiconductor element, an integrated circuit, an electronic component, or the like.

The fine columnar shape (roughening shape) applied to the copper foil surface is formed such that the surface roughness is 1.0 μm or more and 2.5 μm or less in terms of Rz value.
By regulating in this way, a replica having a fine columnar shape and a columnar gap can be formed on the surface of the insulating substrate without leaving an unnecessary etching residue.
Here, if Rz (corresponding to the depth of the replica) is less than 1.0 μm, there is a concern of causing a problem in terms of heat resistance reliability. When Rz exceeds 2.5 μm, the size of the recess formed on the surface of the insulating substrate increases, which may hinder circuit formation. For this reason, the roughening shape of the replica copper foil is particularly preferably 1.0 μm or more and 2.5 μm or less in terms of Rz value.

In the present invention, a fine columnar shape having a gap of 0.1 μm or more and 1.0 μm or less is formed on the roughened surface side of the replica copper foil.
The copper foil before the plating roughening treatment has a fine grain crystal structure. The copper foil having a fine grain crystal structure is a glossy copper foil having a surface roughness Rz value of 1.0 μm or more and 2.2 μm or less before the roughening treatment. A roughened shape having the gap can be provided by roughening a copper foil having a fine grain crystal structure. In other words, it is difficult to obtain the replica shape of the present invention by the roughing bump process using a general electrolytic copper foil base having columnar crystals.
In the present invention, the surface roughness of the untreated copper foil is defined as an Rz value of 1.0 μm or more. The untreated copper foil having an Rz value of less than 1.0 μm has extremely low productivity in the foil-making process, and is industrial. It is because it is unsuitable as a material for use. If the Rz value exceeds 2.2 μm, the initial electrodeposited copper particles in the burnt plating process concentrate and adhere to the tip with high roughness (plating), resulting in dendritic extremely brittle roughening. In order to obtain a healthy state, it is necessary to excessively apply smooth plating in the next step. As a result, it is not only possible to obtain an appropriate uneven space as a replica, but there is a high concern that a dendritic tip becomes a residue in the substrate during etching and causes a migration failure. For this reason, the surface roughness of the untreated copper foil is defined as 2.2 μm or less in terms of Rz value.

The copper for replicas having the roughened bump plating of the present invention, Rz (corresponding to the depth of the replica) of 1.0 μm or more and 2.5 μm or less, and the gap between the roughened bumps of 0.1 μm or more and 1.0 μm or less The foil is laminated to the insulating substrate. Then, in the next step, a cleaning process is performed by a permanganate process for removing the copper foil or the like to finish the insulating substrate surface without damaging the replica shape. Then, an ultra-thin copper film is formed on the surface of the insulating substrate by electroless plating, and the surface of the ultra-thin copper film is subjected to electrolytic copper plating. By doing in this way, the ultra-thin copper foil layer which is excellent in adhesiveness, and is excellent also in etching straightness and thickness uniformity can be formed easily.

The copper foil for replicas of the present invention uses a glossy copper foil having a surface roughness Rz value of 1.0 μm or more and 2.2 μm or less, and is subjected to a roughening bump process.
The discoloration plating bath composition for roughening the copper foil is as follows.
・ Sulfuric acid concentration: 80-120 g / l
Copper concentration from copper sulfate: 20-30 g-Cu / l, preferably 23-25 g-Cu / l
・ Molybdenum compound concentration: 150-350mg-Mo / l
Iron concentration from iron compound: 150 to 300 mg-Fe / l, preferably 250 ± 50 mg-Fe / l
Trivalent chromium concentration from chromium compound: 150 to 300 mg-Cr / l, preferably 250 ± 50 mg-Cr / l
Tungsten concentration from tungsten compound: 0.1 to 20 mg-Cr / l, preferably 10 ± 2.5 mg-W / l
Vanadium concentration or antimony concentration from vanadium compound or antimony compound: 50 to 200 mg-V / l or 50 to 200 mg-Sb / l, preferably 150 ± 30 mg-V / l or 150 ± 30 mg-Sb / l
Chlorine concentration from chlorine compounds: 0.1 to 2.0 mg-Cl / l, preferably 0.1 to 0.5 mg-Cl / l

Using this plating bath, burnt plating is performed under the following plating conditions.
Bath temperature, 20-30 ° C., preferably 23.5-25.5 ° C.
Current density: 25 to 35 A / dm ² by DC rectification, preferably 28 ± 1.5 A / dm ²

The surface of the copper foil subjected to burnt plating has a surface roughness of either the surface peeled off from the surface of the cathode drum of the electrolytic plating foil (glossy surface) or the liquid surface (matte surface). If the Rz value is 1.0 μm or more and 2.2 μm or less, there is no problem.
In the case of an electrolytic copper foil manufactured with a general columnar crystal structure, it is preferable to use the glossy surface side. However, in the case of copper foils made of fine crystals and smooth on both sides (for example, WS foil which is an electrolytic copper foil made by Furukawa Electric Co., Ltd.), the matte side is smoother than the glossy side. Rich. For this reason, when the WS foil is used, the rough matting treatment is performed by subjecting the smooth mat surface side to burnt plating and then the capsule plating treatment, the Rz value is 2.5 μm or less, and the roughening is performed. A rough surface having a shape in which the gap between the bumps is 0.1 μm or more and 1.0 μm or less can be formed.

Next, smooth capsule plating is performed on the surface of the roughened bump-formed shape formed by the above-mentioned burn plating under the following conditions.
・ Sulfuric acid concentration: 80-120 g / l
Copper concentration from copper sulfate: 40-60 g-Cu / l, preferably 50 ± 2.5 g-Cu / l
Bath temperature: 45-60 ° C, preferably 55 ± 2.5 ° C
Current density: DC rectifier with 18 ~ 25A / dm ^2, preferably 20 ± 2.5A / dm ²
In this way, a smooth and healthy columnar shape that does not fall off powder is achieved by subjecting the roughened bump-treated surface to smooth capsule plating.

Thereafter, the copper foil is subjected to organic rust prevention treatment, chromate treatment, nickel treatment or zinc treatment as rust prevention treatment to obtain a roughened copper foil for replica.
The organic rust inhibitor is preferably benzotriazole (1.2.3-Benzotriazole [nominal: BTA]), but may be a commercially available derivative. The amount of treatment may be soaked to the extent that the surface does not discolor copper oxide for up to 24 hours under the salt spray test (salt water concentration: 5% -NaCl, temperature 35 ° C.) specified in JIS-Z-2371.

In the case of nickel-treated rust prevention, the amount quantitatively analyzed as adhering Ni metal may be 0.06 to 0.12 mg-Ni / dm ² (analyzed value per 10 cm). When the roughened surface side exceeds 0.12 mg / dm ² , the possibility of occurrence of a migration failure is increased, which is not preferable. Further, if it is less than 0.06 mg-Ni / dm ² , a sufficient rust prevention effect cannot be obtained.

In the case of zinc-treated rust prevention, the amount quantitatively analyzed as deposited Zn metal may be 0.15 to 0.35 mg-Zn / dm ² (analyzed value per 10 cm). Even if the roughened surface side exceeds 0.35 mg / dm ² , there is no particular problem if the surface is only brassed by the diffusion effect, but an appropriate upper limit is preferably 0.35 mg-Zn / dm ² . On the other hand, if it is less than 0.15 mg-Zn / dm ² , the occurrence of discoloration defects occurs empirically, which is not preferable.
In addition, it can select arbitrarily whether roughening processing is carried out on one side of copper foil, or roughening processing is carried out on both surfaces.

When using the obtained copper foil for replica (for example, copper foil for roughening with a nominal thickness of 9 μm) as a member for BGA (Ball-Grid-Array) (replica), for example, the roughening surface side Bond to the target substrate. And after lamination | stacking, all of this copper foil is etched away efficiently, and it cleans with a permanganate processing liquid. In addition, the permanganic acid treatment liquid has an effect of dissolving metal residues other than copper taken in at the time of burn plating. For this reason, the permanganic acid treatment liquid is an optimal chemical as a pretreatment agent that can achieve the means for wiping out migration concerns and the subsequent electroless copper plating process.

When an ultrathin copper foil having a thickness of 3 μm is required as a BGA application member, electroless copper plating may be applied to the replica surface of the base material in accordance with an electroless copper plating chemical process. Moreover, depending on the case, thickness can be added by electroplating on electroless copper plating, and it can also lead to cost reduction.
In addition, when electroless plating and electrolytic plating are combined and a fine wiring circuit of Line / Space (hereinafter abbreviated as L / S) = 20 μm / 20 μm or less is applied by etching, the electroless plating crystals and electrolysis are used. Care must be taken when processing fine wires because a circuit failure due to the penetration of the etchant may occur at the interface with the plating crystal.

As described above, the electrolytic copper foil is described as an example of the untreated metal foil. However, as an untreated metal foil, it can apply similarly to rolled copper foil, aluminum foil, stainless steel foil, etc. besides electrolytic copper foil.

Next, embodiments of the present invention will be described based on the following examples.

[Example 1]
On the surface side of the untreated electrolytic copper foil having fine crystal grains with a unit thickness of 107 g / m ² (corresponding to a nominal thickness of 12 μm), the surface roughness is 1.5 μm in terms of Rz value, Under the conditions, burnt plating was used to form a roughened bump.
Electrolytic treatment (discoloration plating) was performed with the following bath composition and plating conditions.
・ Sulfuric acid concentration: 100 g / l
Copper concentration from copper sulfate: 23.5 g-Cu / l
・ Molybdenum compound concentration: 250mg-Mo / l
・ Iron concentration from iron compounds: 200mg-Fe / l
・ Trivalent chromium concentration from chromium compound: 200mg-Cr / l
・ Tungsten concentration from tungsten compound: 8.5mg-W / l
・ Vanadium concentration from vanadium compounds: 150 mg-V / l
-Chlorine concentration from chlorine compounds: 0.5 mg-Cl / l
・ Bath temperature: 24.5 ℃
・ Current density: 28A / dm ^{2 by} DC rectification

Subsequently, capsule plating was performed with the following bath composition and plating conditions in order to obtain a strong and sound roughened bump-shaped shape that does not fall off by performing smooth plating on the rough surface of the burnt plating.
・ Sulfuric acid concentration: 100 g / l
Copper concentration from copper sulfate: 50g-Cu / l
・ Bath temperature: 55 ℃
・ Current density: 22 A / dm ^{2 by} DC rectification

Thereafter, the both surfaces of the copper foil were subjected to rust prevention treatment with a known chromate treatment solution (corresponding to 3.0 g / l in terms of CrO ₃ concentration).

The copper foil manufactured in Example 1 was laminated on a commercially available high-frequency insulating substrate (manufactured by Mitsubishi Gas Chemical Co., Ltd.) under the conditions of 220 ° C., 30 kgf / cm ² and 100 min. Thereafter, all the copper foils laminated on the surface were completely dissolved and removed with a cupric chloride etching solution (specific gravity: 1.265; bath temperature: 45 ° C.), and washed thoroughly with water. Next, so-called permanganic acid etching was performed on the replica portion using desmear process liquid (Mc. Dicer 9204, 9275, 9276, 9279) manufactured by McDermit Japan Co., Ltd., and sufficient washing with water was performed. Then, a copper film having a thickness of about 3.0 μm was formed on the surface according to a known electroless copper plating process for thickening (Hitachi, Ltd. AP2 process).

Next, a thin wire circuit for etching test of L / S = 50 μm / 50 μm was formed on the surface of the copper film of the substrate with the electroless copper film, and the straightness of the circuit after etching was observed with an optical microscope (FIG. 1A). reference). Then, mapping observation of metal residues that cause migration, particularly copper, was performed with EPMA (see FIG. 1B). The results are shown in Table 1.
Further, the adhesion strength between the copper film and the insulating substrate was measured, and the results are also shown in Table 1. The adhesion strength (kN / m) is measured by plating the surface of the copper film of the substrate with an electroless copper film to a thickness of 35 μm using a known sulfuric acid-copper sulfate bath, and 0.1 m / m width on the plated surface. The pattern was printed with a UV ink that was cured by UV irradiation and a screen, and the pattern obtained by etching was measured according to JIS-C-6481.
Furthermore, regarding the interval between roughing bumps on the treated surface and the presence or absence thereof, the interval between the outermost contours of the roughing bumps taken at a magnification of a stereomicroscope (see FIG. 1C) passed the JIS standard. Measured using a commercially available micro caliper and converted according to the magnification to obtain the interval. Here, as shown in FIG. 1C, a plurality of columnar shapes are formed at intervals by copper particles being dispersed and adhering to the treatment surface and electrodeposition-grown in a dendritic shape. The plurality of columnar shapes are formed so that the width decreases as the distance from the processing surface increases. For this reason, the interval between the bottoms of the columnar shape was measured as described above. The measurement results are also shown in Table 1.

Determination of the straightness of the circuit after etching shown in Table 1 is based on the observation result of an optical microscope. As shown in FIG. 1 (A), the judgment criteria are ◎ when the etched surface is almost straight in the micrograph, and △ when the linearity is slightly difficult but practically unquestionable. The case where it was judged that there was a problem in practicality was rated as x.
As shown in FIG. 1 (B), the observation of mapping by copper residue is ◎ when the copper residue cannot be completely confirmed by EPMA observation, ○ when the copper residue is almost unidentifiable, or slightly residual, but practically △ indicates that there is no problem.
As shown in Fig. 1 (C), the interval between the rough edges of the roughened bumps on the surface of the treated surface passed the JIS standard, as shown in Fig. 1 (C). The distance between the intervals was obtained by actual measurement using a commercially available micro caliper and converting according to the magnification.

[Example 2]
The single weight thickness of the untreated copper foil having fine crystal grains used in Example 1 is 63 g / m ² (the nominal thickness is equivalent to 7 μm). Except for this point, each treatment was carried out in exactly the same manner as in Example 1 with the discoloration plating conditions, capsule plating conditions, and rust prevention treatment conditions, and the evaluation measurement results are also shown in Table 1.

[Example 3]
It is a unit thickness of 153 g / m ² (corresponding to a nominal thickness of 18 μm) of the untreated copper foil having fine crystal grains used in Example 1. Except for this point, each treatment was carried out in exactly the same manner as in Example 1 with the discoloration plating conditions, capsule plating conditions, and rust prevention treatment conditions, and the evaluation measurement results are also shown in Table 1.

[Example 4]
On the surface where the surface roughness on the liquid surface side of the untreated electrolytic copper foil with fine crystal grains is Rz value of 1.5 μm with a thickness of 107 g / m ² (corresponding to a nominal thickness of 12 μm), the following bath composition And burnt plating was applied to form rough and rough bumps under the plating conditions.
Here, after dissolving each compound so that it might become the following density | concentration with respect to the following basic bath, pH was adjusted to 1.2 with industrial concentrated sulfuric acid, and the copper pyrophosphate electrolytic plating bath was formed.
Basic bath: 300 g / l of potassium pyrophosphate (pyrophosphate compound) is added to a solution of 23.5 g-Cu / l of copper pyrophosphate as a copper concentration. Molybdenum concentration from molybdenum compound: 250 mg-Mo / l
・ Iron concentration from iron compounds: 200mg-Fe / l
・ Trivalent chromium concentration from chromium compound: 200mg-Cr / l
・ Tungsten concentration from tungsten compound: 8.5mg-W / l
・ Vanadium concentration from vanadium compounds: 150 mg-V / l
-Chlorine concentration from chlorine compounds: 0.5 mg-Cl / l
And using the pyrophosphoric acid electroplating bath of said composition, the electrolysis process (burn plating) was implemented on the following conditions.
Liquid temperature: 28.5 ° C
・ DC rectification of current density: 32A / dm ²
Capsule plating after scorch plating is also possible with a copper pyrophosphate bath, but in this example, the treatment was carried out under the same capsule plating conditions and antirust treatment conditions as in Example 1. The evaluation measurement results are also shown in Table 1.

[Example 5]
The surface roughness on the liquid surface side of the untreated electrolytic copper foil having fine crystal grains with a unit thickness of 107 g / m ² (equivalent to a nominal thickness of 12 μm) is 1.5 μm in terms of Rz value under the following conditions. Burn plating to form a roughened bump was applied.
Here, with respect to the following basic bath, each compound was added so that it might become the following density | concentration, and the copper carbonate electroplating bath was formed.
-Basic bath: 23.5 g-Cu / l of copper carbonate as copper concentration is dissolved and adjusted to pH 1.2 with industrial concentrated sulfuric acid-Molybdenum concentration from molybdenum compound: 250 mg-Mo / l
・ Iron concentration from iron compounds: 200mg-Fe / l
・ Trivalent chromium concentration from chromium compound: 200mg-Cr / l
・ Tungsten concentration from tungsten compound: 8.5mg-W / l
・ Vanadium concentration from vanadium compounds: 150 mg-V / l
・ Concentration of chlorine from chlorine compounds as 0.5mg-Cl / l
Then, using this copper carbonate electrolytic plating bath, electrolytic plating treatment (discoloration plating) was performed under the following conditions.
・ Bath temperature: 28.5 ℃
・ Current density is DC rectified: 32A / dm ²
Capsule plating conditions and rust prevention treatment conditions after burn plating were performed in exactly the same manner as in Example 1, and the evaluation measurement results are also shown in Table 1.

[Example 6]
Instead of the untreated metal foil, an industrial general-purpose rolled aluminum foil having a single weight of 68 g / m ² (nominal thickness corresponding to 25 μm) was used. Further, before the burnt plating, the surface was degreased and washed with a 25 g / l sodium hydroxide solution (bath temperature: 85 ° C.). Then, the surface to be burnt plated with a solution obtained by dissolving 50 g / l of zinc oxide in an acetic acid acid bath was subjected to a zinc plating pretreatment of 0.35 mg-Zn / dm ^{2 so} that sound burnt plating could be performed. Except for these points, the burn treatment conditions, capsule plating conditions, and rust prevention treatment conditions were the same as in Example 1, and the evaluation measurement results are also shown in Table 1.

[Comparative Example 1]
When the burn plating treatment for forming the roughened bumps of Example 1 was performed, molybdenum, iron, chromium, tungsten, vanadium, and chlorine were not used as additive metals and additives in the bath. Except for these points, the same capsule plating and rust prevention treatment as in Example 1 were performed, the same evaluation measurement was performed, and the results are also shown in Table 1.

[Comparative Example 2]
Instead of the untreated copper foil having fine crystal grains used in Example 1, a commercially available single-side roughened electrolytic copper foil having a nominal columnar crystal with a nominal thickness of 12 μm (GTS-MP- manufactured by Furukawa Electric Co., Ltd.) 12 μm foil) was used. Except for this point, each treatment was carried out in the same manner as in Example 1 for the discoloration plating conditions, capsule plating conditions, and rust prevention treatment conditions, and the evaluation measurement results are also shown in Table 1.

[Comparative Example 3]
4. Using a known sulfuric acid-copper sulfate bath on the surface of the ultra-thin copper film made of a material in which an ultra-thin copper film having a thickness of about 0.5 μm is formed on one side of a high-frequency compatible core substrate by a general-purpose sputtering method. The membrane was electrolyzed to a thickness of 0 μm and 35 μm. Then, the same evaluation and measurement as in the examples were performed, and the results are also shown in Table 1.

As is apparent from the results shown in Table 1 above, according to the method of the present invention, the circuit etching straightness is superior to those of the comparative examples, there is no fear of migration between circuits, and the member also uses adhesion strength. Thus, a metal wiring film having sufficient strength required for the above-mentioned and improved in quality as compared with an ultrathin copper film obtained by a conventional method can be formed.

Also, by electroless copper plating, it is possible to form a good copper thin film that is dense as a copper crystal and excellent in thickness uniformity. For this reason, it is possible to improve the yield and quality of manufacturing processes for integrated circuits, etc., and to manufacture and provide ultra-thin copper foil that can eliminate defects caused by migration in fine wiring at low cost regardless of sputtering or half-etching. I can do it.

◎ Extremely good (optimal)
○ Good △ No practical problem × No problem

Claims (12)

1. A metal foil having a roughened plating surface, wherein the roughened plating surface is subjected to roughening galvanization by burnt plating on at least one surface of the untreated metal foil, and capsule plating is performed on the roughened galling plating, The surface roughness is 1.0 μm to 2.5 μm in Rz value, and the roughening bump formed by the roughening bump plating has a roughness between 0.1 μm and 1.0 μm between adjacent roughening bumps. A metal foil having a columnar shape having a gap.
2. The metal foil according to claim 1, wherein the roughened plating surface is subjected to a rust prevention treatment.
3. The untreated metal foil is a rolled copper foil or an electrolytic copper foil, and the surface roughness of at least the plated roughened surface forming side of the untreated copper foil is 1.0 μm to 2.2 μm in Rz value. Metal foil of description.
4. The single heavy Mi of untreated copper foil, a metal foil according to claim 3 from 60 g / ^{m 2} is 153 g / ^{m 2.}
5. A metal foil in which the metal foil according to any one of claims 1 to 4 is used for a replica.
6. 6. An insulating substrate having a roughened surface formed by transferring the uneven shape on the roughened plating surface of the metal foil according to claim 5.
7. A wiring board in which a predetermined wiring pattern is formed on the roughened surface of the insulating substrate according to claim 6.
8. An untreated metal foil having a surface roughness Rz value of 1.0 μm to 2.2 μm is subjected to burnt plating in a plating bath in which an additive metal is added to a sulfuric acid-copper sulfate plating solution, a pyrophosphate copper plating solution or a copper carbonate plating solution. The surface of the roughened galvanized surface is encapsulated and capsule-plated on the surface of the roughened galvanized surface. The surface roughness is 1.0 to 2.5 μm in terms of Rz, and 0.1 μm or more between adjacent roughened galvanized bumps. A method for producing a metal foil having a roughened plated surface with a columnar shape having a gap of 1.0 μm or less.
9. The method for producing a metal foil according to claim 8, wherein the additive metal added to the plating solution is iron, chromium, molybdenum, tungsten, and / or vanadium and antimony.
10. The method for producing a metal foil according to claim 8, wherein the roughened plating surface is subjected to a rust prevention treatment.
11. The method for producing a metal foil according to claim 8, wherein the untreated metal foil is a rolled copper foil or an electrolytic copper foil.
12. A method for producing a metal foil, wherein the metal foil treated by the production method according to any one of claims 8 to 11 is used for a replica.

Images